2008 NORTHEASTERN NATURALIST 15(Monograph 2):33–66 II. Nesting Behavior of Tachysphex pechumani (Hymenoptera: Crabronidae) Frank E. Kurczewski* Abstract - A re-examination of the nesting behavior of T. pechumani from 1991 to 1999 at 43 sites in the central Great Lakes Region and southern New Jersey revealed little difference between the two groups. More than 200 females were observed nesting solitarily in June–July in sandy soils of mostly oak/pine-dominant barrens, savanna, and open woodland. Tachysphex pechumani was univoltine, with a flight period encompassing mainly late spring–early summer. Emergence and senescence of wasps occurred earlier in the southern and later in the northern parts of the species’ range. Males were not territorial and dug resting burrows for the night and to avoid the hot sand and inclement weather. Nesting aggregations ranged from a few to 48 females at a site. Distinct bimodality in nesting occurred on hot days, with peak activity in late morning and a secondary rise in activity in mid- to late afternoon. Wasps demonstrated genus-atypical burrow excavation and tumulus formation. Rather slow and jerky movements characterized female behavior. There was little variation among females in burrow excavation, orientation, hunting, prey capture, prey transport, and final closure. Geographic variation included longer burrows and deeper cells at many southerly locations. Females preyed mostly on nymphal Melanoplinae and Gomphocerinae (Acrididae), primarily Melanoplus species. Some Melanoplus species were captured earlier in the season than Gomphocerinae in synchrony with their earlier emergence and growth schedules. Wasps faced and circled prey while waving antenna before pouncing on and stinging the grasshopper. The relatively large prey was often transported to the nest slowly and haltingly. Random positioning of paralyzed grasshoppers near entrances constituted genus-atypical behavior. A single paralyzed prey was placed commonly head inward and ventral side upward in the one-celled nest. The wasp’s egg was laid transversely across the grasshopper’s pro- and mesosternum. Some females completed two nests per day under favorable weather conditions. Sarcophagid flies of the tribe Miltogrammini (Sphixapata rubriventris, S. vigilans, S. trilineata, Sphenometopa tergata, Taxigramma heteroneura) were major enemies of this wasp. Introduction Species of Tachysphex are mostly small, largely cursorial, fastmoving digger wasps as the genus name implies (tachy = swift, sphex = wasp) (Williams 1914). Eighty-three species inhabit North America and the Caribbean Region (Pulawski 1988). Species that occur in the Austral Faunal Zone are mainly bi- or multivoltine, whereas species that inhabit the Boreal Faunal Zone are univoltine (Pulawski 1988). The North American species excavate mostly short burrows and shallow cells in sandy, gravelly or, rarely, loamy soils. They store their cells with paralyzed orthopteroid insects, primarily nymphal grasshoppers (Acrididae). *PO Box 15251, Syracuse, NY13215; Fkurczewski@twcny.rr.com. 34 Northeastern Naturalist Vol. 15, Monograph 2 Information on the nesting behavior of the nearctic species has been summarized by Krombein (1979) and Pulawski (1988). Tachysphex pechumani Krombein, the antenna-waving wasp, is one of the most distinctive acridid-hunting congeners based on adult morphology, nesting behavior, ecology, and geographic and seasonal distribution (Kurczewski 1987a). This highly psammophilous species exhibits marked sexual dimorphism in size and coloration (Kurczewski et al. 1970, Pulawski 1988). The smaller male is entirely black. The larger female has 5–9 long orange apical antennal segments, brassy-golden frontal vestiture, a wide distance between the compound eyes, and 2–3 orange-red basal abdominal segments on a predominantly black body. Olive-green eyes are a reliable distinguishing field characteristic in both sexes. Unlike many Tachysphex, T. pechumani has only one adult flight period annually bracketing the summer solstice (Kurczewski and Elliott 1978, Kurczewski et al. 1970). Such an abbreviated flight season coincides with maximal photoperiod, full leaf canopy, high relative humidity and nonflammable (green) understory resulting in fewer wildfires, and peak abundance of potential prey grasshoppers (Kurczewski 1998). Unlike some other Tachysphex, T. pechumani exhibits a bimodal pattern of provisioning, with morning and mid- to late afternoon foraging sessions on hot sunny days. High sand temperatures from noon until mid-afternoon induce a noticeable decrease or cessation in nesting activity (Kurczewski 1998). The nesting behavior of T. pechumani contains numerous components not seen in other nearctic Tachysphex (Kurczewski and Elliott 1978). The movements of the female are rather slow and jerky. Wasps display an almost incessant waving of the genus-atypical long antennae. A flattened, fan-shaped, dark-colored tumulus results from the subterranean manner of burrow excavation in soil with a fire history (Fig. 1). A loose, often incomplete, temporary closure of the entrance is made prior to searching for prey. Wasps sometimes hunt for prospective grasshoppers in a series of winding and hovering flights and capture prey after circling it one or more times on the ground. They position the paralyzed grasshopper randomly near the entrance before pulling it into the nest. Females store one relatively large, usually nymphal melanopline or slant-faced phytophilous acridid in a singlecelled nest. Because of its size, this grasshopper is transported head forward on the ground to the nest, often slowly and haltingly. The primary goals of this study were: (1) define seasonal distribution; (2) determine wasp abundance in nesting aggregations; (3) describe male behavior; (4) categorize, analyze, and quantify nesting behavior components; and (5) compare nesting behavior for the central Great Lakes Region and southern New Jersey groups. Species of Tachysphex are a rewarding group for study because of their varied nesting behavior (Bohart and Menke 1976). Tachysphex pechumani is a featured player in such a scenario because of its unique adult morphology, nesting behavior, ecology, and geographic and seasonal distribution (Kurczewski 1987a). 2008 F.E. Kurczewski 35 Methods State/province soil association maps, United States Department of Agriculture soil surveys, pre-settlement vegetation maps and aerial photographs were used to locate excessively/well-drained sandy soils. Preference was given to areas that comprised ancestral oak savanna and pine barrens or had a history of periodic fires or prior T. pechumani collections. Ninety-eight days and 582 h were spent in 1991–1999 observing T. pechumani in northwestern Indiana (1 day), Lower Peninsula of Michigan (40), northwestern Ohio (9), southwestern Ontario (34), and southern New Jersey (14). Two hundred seventy-five nests were excavated and examined at 43 sites. Specific locations, date(s) of observation, and number of nests are given in Table 1. Observations made by Mark O’Brien in the early 1980s at the Allegan State Game Area (SGA) and Pinckney State Recreation Area (SRA), MI are included. At least one male or female was collected from each site to serve as a voucher specimen. Live females were hand-netted, marked on their mesoscutum with non-toxic paint, released at the site, and followed. Minimal abundance Figure 1. Tachysphex pechumani open nest entrance, dark-colored tumulus, and surrounding sand and vegetation. 36 Northeastern Naturalist Vol. 15, Monograph 2 was estimated by counting the number of wasps at a site and associating them with specific nests. Nests were marked with colored toothpicks that were dated and numbered chronologically. Nest density was estimated Table 1. Location, date(s) of observation, and number of Tachysphex pechumani nests. Abbreviations: CFB = Canadian Forces Base, CF = Crown Forest, MT = Manestar Tract, NF = National Forest, SF = State Forest, SGA = State Game Area, SRA = State Recreation Area, TPT = Turkey Point Tract, UMBS = University of Michigan Biological Station, and WMA = Wildlife Management Area. State/County Location Date No. Indiana Porter Pine Township 21 Jun 1999 5 Lower Michigan Allegan Allegan SGA. 24 Jun 1984 6 15-18 Jun 1991 26 11,12,28 Jun 1992 14 10-16 Jun, 12 Jul 1993 8 12 Jun 1994 2 Arenac Alger Cemetery 8 Jul 1993 4 22 Jun 1994 5 Barry Barry SGA 12 Jun 1994 1 Cheboygan UMBS 29 Jun 1992 6 21 Jun 1994 1 Hardwood SF 10 Jul 1993 1 Crawford Au Sable SF 30 Jun, 5,6 Jul 1992 10 8,9 Jul 1993 7 Emmet Hardwood SF 21 Jun 1994 1 Gladwin Tittabawassee River SF 22 Jun 1994 1 Iosco Huron NF (B) 22 Jun 1994 6 Kalkaska Kalkaska SF 9 Jul 1993 1 Lake Luther Valley Cemetery 11 Jul 1993 3 Livingston Island Lake SRA 23 Jun 1994 1 Manistee Manistee NF (D) 12 Jul 1993 1 Mason Manistee NF (C) 12 Jul 1993 1 Montmorency Thunder Bay River SF 10 Jul 1993 3 Muskegon Manistee NF (E) 20 Jun 1994 4 Newaygo Manistee NF (A, B) 19,20 Jun 1991 6 12, 29 Jun 1992 6 11 Jul 1993 1 Oceana Pines Point SRA 12 Jul 1993 1 Ogemaw Ogemaw SF 8 Jul 1993 1 Oscoda Huron NF (A) 9 Jul 1993 4 Otsego Otsego SF 10 Jul 1993 1 Presque Isle Black Lake SF 10 Jul 1993 1 Roscommon Houghton Lake SF 5 Jul 1992 6 Washtenaw Pinckney SRA 21,27 Jun 1981 7 14 Jun 1982 2 Wexford Fife Lake SF 11 Jul 1993 1 Ohio Lucas Melke Road Savanna 15 Jun 1999 1 Mescher Road 16, 20-22 Jun 1999 9 Sager Road Ponds 23 Jun 1993 1 Oak Openings Preserve 14-19 Jun 1999 13 Metropark 2008 F.E. Kurczewski 37 by measuring the distance between adjacent nest entrances. Soil samples were collected from a depth of 0–40 mm at eight sites in Lower Michigan and two sites in New Jersey. The sand grains were separated by particle size at the State University of New York College of Environmental Science and Forestry, Syracuse, NY. Nesting aggregations were observed daily from 0800 to 1900 hours (Eastern Daylight Time), weather permitting. Aggregation is defined herein as a group of conspecific individuals occurring together at a site. Type of wasp activity was noted, described, and quantified. Emphasis was placed on burrow excavation, tumulus formation, temporary closure, orientation flight, hunting, prey capture, prey transport, nest entry, and final closure. Wasp activity was plotted against time of day, air temperature arbitrarily positioned at 1.5 m above ground level in the shade, and sand surface temperature. Narrow-range mercury thermometers with the sensors unshielded were used to measure air and sand surface temperatures. Burrows and cells were excavated, examined, measured, and drawn. Tumulus configuration and dimensions, burrow design and length, cell depth, cell shape, cell size, position of prey in cell, and placement of wasp’s egg on prey were recorded in the field. Prey were removed from the cells, put in individual vials according to nest number, placed on ice in a cooler, transported to a laboratory, and weighed (wet) on a Mettler balance. The grasshoppers were then transferred to vials with glycerol, code-labeled, and identified. The wasp voucher specimens were placed in individual vials, put on ice in a cooler, transported to a laboratory, weighed, frozen, pinned, and code-labeled. Table 1, continued. State/County Location Date No. Ontario Lambton Karner Blue Sanctuary 27 Jun 1996 4 Pinery Provincial Park 27 Jun 1996 1 Watson Property 27 Jun 1996 2 Norfolk St. Williams CF,MT 26 Jun 1996 1 St. Williams CF,TPT 21,26 Jun 1996 21 Simcoe CFB Borden 27,28 Jul 1996 9 13 Jul 1997 4 5,6,18 Jul 1998 18 29 Jun-2 Jul 1999 4 New Jersey Atlantic Galloway Township 16 Jun 1996 2 Hammonton Creek WMA 21 Jun 1997 5 25 Jun 1998 3 Wharton SF 15,16 Jun 1995 2 14-16 Jun 1996 8 Burlington Bass River SF 20 Jun 1995 1 Chatsworth Woods 22 Jun 1997 2 Lebanon SF 20,21 Jun 1995 8 Ocean Barnegat Township 24 Jun 1998 1 38 Northeastern Naturalist Vol. 15, Monograph 2 Maggots found in wasp cells were placed in pre-moistened, plastic, sand-filled film canisters after they had finished feeding. Following pupariation, the fly puparia were collected and placed individually in moistened, sand-filled glass vials with perforated plastic tops. The vials were left in the laboratory at room temperature and watered periodically. Adult flies that emerged from the puparia were frozen, pinned with their respective puparia, code-labeled, and identified to serve as voucher specimens. Male behavior was studied at the Allegan SGA (48 males, 15–17 June 1991, 11–12 June 1992, 11–16 June 1993); Houghton Lake State Forest (SF) (8 males, 29 June 1992); Au Sable SF, MI (18 males, 30 June, 5–6 July 1992); and St. Williams Crown Forest Turkey Point Tract, ON (24 males, 20–21 June 1996). Emphasis was placed on emergence, maintenance, copulation, and resting burrows. Two live males and two live females from the Allegan SGA, MI were put in individual vials 12 June 1994 at 1600 h, placed atop ice filling a 2 gallon cooler at 1 °C for 24-, 48-, 72-, and 96-hour-long periods. The longevity of the wasps under such cold temperature conditions was determined to assess the usefulness of this procedure for manipulating them in future studies. A two-sample t-test was used to test for differences in tumulus dimensions, mean burrow length, and mean cell depth between the New Jersey and central Great Lakes Region samples and for differences in entrance diameter, burrow length, and cell depth between loose and compact sand samples. Burrow length and cell depth plotted against site latitude, annual precipitation, and mean annual temperature were tested using analysis of variance. Comparison of annual variation in burrow length and cell depth at some Michigan and Ontario sites was made with one-way analysis of variance. The relationship between sand surface temperature and burrow excavation, opening temporary closure, and final closure was tested using simple linear regression and Pearson’s correlation. Simple linear regression and Pearson’s correlation were also applied to burrow length and tumulus surface area, duration of nest closure and burrow length, cell length and prey weight, and prey weight and wasp weight. Statistical significance was assumed when P < 0.05. Results Seasonal distribution The earliest and latest collection dates on specimens in insect museums are 21 May (1912, Atco, Camden County, NJ) and 17 July (1972, Pontiac SRA, Oakland County, MI) (Fig. 2). Four females from Luzerne, Oscoda County, MI collected in windowpane traps bear labels dated 19 August 1966, but it is not known how long these specimens laid in the traps before being retrieved. Other windowpane-trapped specimens from this locality and Montmorency County, MI are dated 18–27 July 1966. Mating and nesting occurred in June and July. Individual marked females were observed for an average of 21.7 days (range = 14–27, N = 27). An 2008 F.E. Kurczewski 39 aggregation at the Allegan SGA, MI was active for 34 days (11 June–15 July 1993). An aggregation at the St. Williams Crown Forest Turkey Point Tract, ON was active for at least 36 days (from before 20 June until 26 July 1996). An aggregation at the Karner Blue Sanctuary, ON was observed from 25 June until 25 July 1996, but the wasps probably emerged before 25 June as two males collected on 27 June had frayed wings (Jeff Skevington, Canadian National Collection of Insects, Arachnids, and Nematodes, Ottawa, ON, Canada, 1996 pers. comm.). An aggregation at the Oak Openings Preserve Metropark, Lucas County, OH was observed 6 June–11 July 2007 for a total of 36 days (Robert Jacksy, Oak Openings Preserve Metropark, Toledo, OH, 2007 pers. comm.). Emergence and senescence occurred earlier in the south than in the north with wasps appearing from late May in New Jersey to August in northern Lower Michigan (Fig. 2). Males and females emerged and disappeared sooner in New Jersey than in the central Great Lakes Region. Tachysphex pechumani appeared earlier in Indiana, Ohio, and southern Lower Michigan than in central and northern Lower Michigan, often by two or three weeks. In 1992 in Michigan, 20 days elapsed between emergence at the Allegan SGA (9 June) and the University of Michigan Biological Field Station (29 June). In 1994 in Michigan, 12 days separated emergence at the Allegan SGA (9 June) and the Hardwood SF, Emmet County (21 June). Adults in Indiana, Ohio, and southern Lower Michigan usually disappeared two to three weeks before those in central and northern Lower Michigan. In 1996 in Ontario, emergence at the St. Williams Crown Forest Turkey Point Tract (before 20 June) preceded that at Canadian Forces Base (CFB) Figure 2. Number of Tachysphex pechumani collected and observed in New Jersey (white) and central Great Lakes Region (black) in 1902–2006. 40 Northeastern Naturalist Vol. 15, Monograph 2 Borden (5 July) by at least 15 days. At the former locality, adults often disappeared two to three weeks before those at CFB Borden. Late season females with perfect wings, complete foretarsal digging rakes, and clean integument were observed on 5 and 9–10 August 1992 and 1 and 10 August 1993 at Au Sable SF and on 1 and 11 August 1993 at Hardwood SF, Cheboygan County (Fig. 2). Without males, these wasps remained unfertilized, walked and rested on the sand, hovered when the surface became hot, made low flights, and sporadically excavated unfinished burrows. They did not hunt for prey. Cold temperature and longevity Two males and two females from the Allegan SGA all revived after 24-, 48-, and 72-hour-long periods in vials on ice in a cooler at 1 °C. After 96 h, all four wasps moved their appendages when exposed to field temperature (30 °C), but none recovered. Activity conditions Males and females were seen mainly on warm, sunny days. Mating and nesting ceased upon full cloud cover and overcast skies, although no rain had fallen. Males and females were seen excavating and then closing themselves within burrows in sand at the periphery of the nesting area from 1820 Figure 3. Number of Tachysphex pechumani observed in burrow excavation (white) and final closure (black) plotted against time of day. 2008 F.E. Kurczewski 41 Figure 4. Number of Tachysphex pechumani observed in burrow excavation (white) and final closure (black) plotted against sand surface temperature. to 1843 h. Temperature rather than photoperiod seemed to govern when females first appeared at nests in the morning as there was a difference of 1.25 h between earliest arrivals on successive days. Earliest female appearances at nests (EDT) were 0823 at Wharton SF, NJ; 0847 at University of Michigan Biological Station; 0851 at Oak Openings Preserve Metropark, OH; and 0908 at Allegan SGA. Earliest male appearances at the Allegan SGA were 0854 and 0856. Earliest copulation seen at that site was at 1023. Latest sightings of males and females were 1847 at the Allegan SGA and 1858 at the Au Sable SF. Burrow excavation by females was seen from 0908 to 1843, with maximal activity at 1100–1159 (Fig. 3). Final closure was observed between 0918 and 1858, with maximal activity from 1000 to 1159 and 1400 to 1659 (Fig. 3). Some females dug burrows in mid- to late afternoon (1500–1759). They captured prey, oviposited, and closed the nests the following morning (1000–1059). These wasps excavated new burrows in late morning (1100– 1159) before disappearing at midday when sand temperatures became high. Males and females were active in the morning and late afternoon at air and sand surface temperatures as low as 16.5 and 21.5 °C, respectively. Wasps made brief flights up to 30 cm long at these temperatures. Copulation was observed at air and sand surface temperatures as low as 19 and 29 °C, respectively. Females dug burrows, temporarily closed them, and oriented, but did not hunt for prey at air and sand surface temperatures as low as 18 and 42 Northeastern Naturalist Vol. 15, Monograph 2 24 °C, respectively. One wasp oviposited and closed her nest at air and sand surface temperatures as low as 19 and 29 °C, respectively. Females nested in mid-afternoon at air and sand surface temperatures as high as 34 and 56 °C, respectively (Fig. 4). Males were observed in mid-afternoon at air and sand surface temperatures as high as 28 and 54 °C. Most burrow excavations by females were made at sand surface temperatures ranging from 36 to 50 °C (mean = 42.3 ± 7.33, N = 85; Fig. 4). The majority of final closures occurred at sand surface temperatures varying from 36 to 45 °C (mean = 41.8 ± 5.83, N = 154; Fig. 4). There was distinct bimodality in nesting on hot days with peak activity from 1000 to 1159 and a second rise from 1400 to 1659 (Fig. 3). All males and most females left the bare sand before the sand surface temperature attained 55 °C. At high sand surface temperatures, males entered resting burrows, while many females flew to and rested on vegetation in the shade. On cool days (air temperature = 24–26 °C), females nested without break, furthering the notion that wasp activity or inactivity is governed by temperature. Male behavior Males emerged a day or two before the females and lived one to two weeks. Males may live longer than this under adverse weather conditions as they can remain inactive in burrows below ground for extended periods. Males were more numerous than the females for a few days following their emergence. Males outnumbered females 40:14 on 11 June 1992 at the Allegan SGA. On 5 July 1992, males outnumbered the females 15:10 at the Au Sable SF. Recently emerged males rested, walked on the surface for short distances, and made brief low flights back and forth above the sand. Such flights were 1–4 m long, 1–3 cm above the surface, and contained no vertical or hovering components. Upon landing, a male lowered his wings on the dorsum, waved his antennae for a second or two, sometimes turned 180°, and remained still. Males perched motionless on sandy knolls and ridges, twigs, stems, and dried leaves with the head raised above the thorax and abdomen. They avoided landing on stones in the afternoon on hot days. Males held the antennae upward, outward, close together, and motionless. Before taking flight, males lowered the antennae and moved them alternately or in unison. Males frequently cleaned the antennae with the forelegs and, less often, cleaned the wings and abdomen with the hindlegs. The duration of perching on warm sunny days was brief, usually 10–20 sec. Males rested for considerably longer periods on cool, partly overcast days. Male territoriality was not apparent. Three or four males sometimes rested and walked for short distances (1–6 cm) on the same sandy knoll without exhibiting aggressive behavior. However, males often pursued one another in flight if one wasp flew too closely or landed nearby and then flew off. Such pursuits sometimes added a third male, the trio flying in tandem just above 2008 F.E. Kurczewski 43 the sand surface. The pursuer often returned to the same place, landed, and remained motionless. Males attempted to copulate with recently emerged and nesting females and other small insects, apparently being attracted by their size and movement. If a male pounced on an unreceptive female, he usually took flight after a second or two. Such a female moved to one side to avoid an oncoming male or turned the end of her abdomen downward to avoid genitalic contact. When a male flew onto the dorsum of a receptive female, he immediately lowered his wings and held her wings with his forelegs to prevent her from flying. Because the female was larger than the male, she had to raise her abdomen to achieve coupling. Three males observed in copula weighed 11, 12, and 17 mg, and the females weighed 27, 26, and 42 mg, respectively. During copulation, both male and female remained motionless for 38–55 sec, except the male abdominal segments moved rhythmically. Three males tried unsuccessfully to disengage one copulating pair by landing in quick succession atop them. After the copulating male dismounted, the female raised and held her wings in an elevated position, then lowered her wings, cleaned herself, and rested on the surface. The male cleaned himself with his forelegs and flew away. Males dug short, straight, simple burrows in the sand in which they spent the night or retired during inclement weather and high sand temperatures. They occupied these burrows for two successive days or excavated a new burrow each day. Males excavated the burrows using the mandibles and forelegs in unison. One excavation, 28 mm long, took 22 min to complete. Many male burrows were dug in late afternoon (1755–1847). A male entered such a burrow, filled the entrance with sand from below, and remained inside in a head outward position. Male burrows were located on the periphery of the nesting area. They were dug in low sand ridges or level sand and faced north, east, and south. Sixteen of 20 male burrows at the Allegan SGA in 1991 were dug in a 5–20° slope near the top of a low sand ridge in an area 110 x 20 cm. Four other burrows were dug in flat sand at the bottom of the ridge. Some entrances were separated by only 3–7 cm. Six entrances were 3.5–5.0 mm in diameter. Tumuli in front of the burrows were 14–25 mm long and 13–29 mm wide. The burrows were 17–28 mm (mean = 23.1 ± 4.35, N = 20) long. Eight male burrows at this site in 1993 occupied a 35 cm-long portion of the sand ridge, with a ninth burrow 40 cm away. Eight male burrows at the Au Sable SF were in level sand at the edge of a tire impression on an off-road vehicle trail. The burrows were in single file and separated by 4–7 cm. Four other burrows at this site, 3–6 cm apart, were in a low ridge in the center of the trail. Nest location and density Nesting aggregations usually occupied compact, sometimes hard-packed, level sandy soil. Females nested mainly in very coarse and coarse sand, the 44 Northeastern Naturalist Vol. 15, Monograph 2 grains measuring 0.5 to >2.0 mm in diameter. The wasps selected very coarse and coarse sand even where fine sand (0.10–0.25 mm in diameter) was available for nesting. Nests in close proximity usually denoted the activity of a single female. Wasps tended to excavate and complete successive burrows in one area before moving a short distance to make additional nests. Such localization probably reduced the incidence of fighting and prey stealing, but may have increased the incidence of cleptoparasitism by satellite-flies. Wasps at seven sites moved 4–52 cm (mean = 15.1 ± 9.13, N = 92) between successive excavations. Nests belonging to different wasps in one aggregation in Lucas County, OH were as close together as 150–185 cm (N = 9) and as far apart as 12–52 m (N = 5). From 0.7 to 2.1 m separated nests of four females nesting simultaneously at CFB Borden. Aggregation size Aggregation size and wasp abundance varied annually depending on fecundity, mortality from cleptoparasites (especially satellite-flies), weather conditions, and site disturbance. Many T. pechumani aggregations had only a few wasps. However, one aggregation at the St. Williams Crown Forest Turkey Point Tract had 48 females in 1996 (Table 2). Aggregations at CFB Borden contained nine females in 1996 (Table 2), none in 1997, four in 1998, and five in 1999. Burrow excavation Unmated females dug consecutive unfinished burrows for up to two days following emergence. They abandoned such excavations by turning 180° Table 2. Number of females and nests in some larger Tachysphex pechumani nesting aggregations. CFB = Canadian Forces Base, SF = State Forest, and SGA = State Game Area. F = number of females, N = number of nests. Locality F N Dates Source1 Allegan SGA, MI 10 26 15-18 Jun 1991 FEK2 Allegan SGA, MI 6 14 11,12,28 Jun 1992 FEK Au Sable SF, MI 10 9 30 Jun, 5,6 Jul 1992 FEK Pine Township, IN 7 183 21 Jun 1999 Kurczewski 2000b Oak Openings Preserve 29 683 14-23 Jun 1999 FEK Metropark, OH St. Williams Crown Forest, ON 48 21 21, 26 Jun 1996 Kurczewski 2000a St. Williams Crown Forest, ON 36 1043 25–29 Jun 1997 Kurczewski 2000a CFB Borden, ON 9 153 26–28 Jul 1996 Kurczewski 2000a Weymouth, NJ 13 27 Jun–1 Jul 1926 Kurczewski et al 1970 Weymouth, NJ 15 20 11-14 Jun 1968 Kurczewski et al 1970, Kurczewski and Elliott 1978 Elwood, NJ 12 14 Jun 1968 Kurczewski et al 1970 Lebanon SF, NJ 8 123 20–21 Jun 1995 FEK Wharton SF, NJ 7 113 14–16 Jun 1996 FEK 1Reference source for data. 2F.E. Kurczewski, unpublished data. 3Includes unexcavated nests. 2008 F.E. Kurczewski 45 and flinging sand into the opening with the forelegs. One wasp began nine excavations in 11 min. Senescent females with frayed wings also spent much time excavating burrows that were never used for nesting. They, too, abandoned such an excavation by turning and throwing sand into the opening with the forelegs. Some old wasps entered burrows they had dug previously and closed themselves inside during midday at sand surface temperatures of 34–38 °C. Unused burrows remained open even though females turned and flung sand into them when leaving. Twenty-four burrow excavations were observed from start to finish. A female searching for a place to dig walked zigzag on the sand in a jerky manner. She moved faster and wobblier as sand temperature increased. At high sand surface temperatures (>50 °C), wasps made short, quick “hopping” flights to avoid the hot sand or they flew to and rested on vegetation between bouts of digging. Females tapped their antennae alternately on the sand in certain spots, pausing occasionally to clean them with the forelegs. Some wasps stopped and slowly waved their antennae, raised their wings above the dorsum, and/or walked in half-circles or sideways on the sand before beginning an excavation. A female began excavating with her mandibles and removed the loosened sand backward using the well-developed foretarsal digging rakes in unison (Fig. 5). She raised her abdomen synchronously to allow the soil to be thrown beneath and behind her. She held her wings flat on the dorsum. Females made 3–9 (mean = 5.7 ± 1.83, N = 20) hovering and turning flights above the opening at sand surface temperatures of 38–55 °C during the first 2–3 min of excavation. Wasps flew upward to 10–12 cm, hovered facing the entrance, and then turned a complete circle to the left or right before landing. Four wasps digging at sand surface temperatures of 26–42 °C made no such flights when beginning an excavation. The female that made nine hovering flights (54 °C) turned a complete circle during her first seven ascents, landed, and walked into the burrow flinging sand backward. She turned a complete circle to the left and one to the right on her eighth hovering flight, landed, entered the burrow, and flung sand backward. On her ninth flight she turned two complete circles to the right and one to the left before landing, entering, and flinging sand backward. No such flights were seen during excavation once a female disappeared below ground level. Wasps excavating burrows at the Allegan SGA rarely backed onto the surface when removing the loosened sand. Instead, they periodically threw sand backward in an arc, 2–5 cm high and up to 12 cm long, from inside the burrow. Some females backed out of their entrances 2–3 times per excavation, flinging sand, with only the end of the abdomen exposed. In contrast, wasps excavating burrows at other localities backed from entrances nearly the entire length of their body 6–15 (mean = 10.8 ± 3.55, N = 12) times when removing loosened sand. However, even these females did not back beyond their body length onto the tumulus. 46 Northeastern Naturalist Vol. 15, Monograph 2 After excavating a burrow and cell, the female appeared headfirst in her entrance, flung sand backward from the tumulus into the opening using the forelegs in unison, and, backing in, tamped the fill with the shiny, trowel-shaped pygidium (last abdominal tergite). This routine comprised the temporary closure of the nest entrance. Most wasps removed sand from directly in front of the opening, but one female walked completely around her entrance to obtain sand. Females exited entrances 1–8 times to get sand and turned 180° toward the closure 0–8 times. During the latter stages of filling, wasps turned 0–4 circles in front of an entrance and made 0–5 hovering flights above the area, each time turning completely around in mid-air. Some females stopped hovering, flew to vegetation nearby, and rested. Such wasps returned to their burrows and resumed hovering interspersed with filling the opening. Females left the area by walking in enlarging circles or figure eights at sand surface temperatures of 35–54 °C (N = 22) or making low circular flights of increasingly larger radii at sand surface temperatures of 54 and 55 °C (N = 2). Wasps spent 17–38 s (mean = 27.1 ± 6.80, N = 24) throwing sand into entrances at surface temperatures of 35–55 °C. However, entrances were never filled flush. Most entrances remained partly to entirely open and depressed 5–8 mm. The most complete fills were depressed 1–3 mm. Wasps that alternated making hovering flights with filling, left the entrances from half to entirely open. Females took 15–49 min (mean = 26.4 ± 10.32, N = 24) to excavate a burrow and cell and partly fill the entrance upon leaving, the longest times Figure 5. Tachysphex pechumani female removing loosened sand from burrow with forelegs. Mid- and hindlegs are used for walking. 2008 F.E. Kurczewski 47 being associated with hard-packed sand. Burrows dug at higher sand surface temperatures took significantly less time to excavate than burrows dug at lower sand surface temperatures (Fig. 6). Some wasps spent 7–9 min near the end of an excavation apparently for shaping an enlarged terminal cell. Although slightly larger tumuli accompanied longer and deeper burrows, there was no correlation between burrow length and tumulus surface area, possibly because of the genus-atypical manner of sand removal (R2 = 0.02, P = 0.32). Tumuli were longer (mean = 98.8 ± 9.9 mm, range = 80– 110, N = 8) in southern New Jersey than in the central Great Lakes Region (mean = 87.5 ± 19.1 mm, range = 27–130, N = 52) (P = 0.02, df = 16). Hunting and prey capture Females hunted for prey in vegetation bordering the nesting area. Many wasps searched no farther than 7–10 m from their nests. They walked or ran zigzag on the ground, tapped the substrate with their antennae, and held their wings on the dorsum. Wasps did not react to Dissosteira carolina (Linnaeus) (Oedipodinae) (Carolina grasshopper) when individuals leapt in front of them. Some wasps, while searching for prey, made hovering flights 20–30 cm above low grasses interspersed with slow winding flights between upright plants. Periodically, females paused and Figure 6. Tachysphex pechumani burrow excavation duration plotted against sand surface temperature. 48 Northeastern Naturalist Vol. 15, Monograph 2 cleaned their antennae with their forelegs and their abdomens with their hindlegs. Wasps occasionally landed on upright vegetation and remained perfectly still, assuming a parallel or nearly perpendicular posture relative to the plant. Wasps grasped the plant with their mid- and hindlegs, dangled their front legs and waved their antennae alternately or held them motionless, nearly touching and straight. If unsuccessful in capturing prey, a female made a short, low, quick flight to a new area or returned periodically on the ground to her nest. One wasp returned to her nest 16 times in 2.5 h at sand surface temperatures of 38–40 °C. At the nest, a female examined the entrance and then walked or flew away or she removed the sand fill, entered the burrow, exited headfirst, refilled the opening, and walked or flew back to the hunting locale. Some wasps made hovering and turning flights when removing the fill or refilling the entrance. As sand temperatures rose, the number of hovering flights increased to several in succession and entrance closures became looser and more open. Five females were observed capturing prey. One wasp, after detecting a grasshopper, flew quickly back, landed facing the prey, and began waving her antennae. Other hunting females approached a grasshopper on the ground face to face, alternately waving their antennae, and circled the prey clockwise or counter-clockwise. Wasps circled the grasshopper up to two times in one direction and once in the opposite direction before pouncing on it from the side. Maintaining her body at about a 90° angle to the longitudinal axis of the prey and, clinging to its dorsum, she bent her abdomen underneath and inserted her sting in the underside of its thorax. One wasp stung the grasshopper successively in the hind- and midcoxal coria. Another female stung her prey in the right mouthparts for 1–2 s, then the right foreleg for 10 s, before stinging it in the mid- or hindcoxal corium. The wasp released her grasp of the grasshopper, walked a few centimeters away, and cleaned her antennae, hindlegs, and end of abdomen. Four females returned to their paralyzed prey, straddled it ventral side upward or on its side, and applied the mandibles to the base of a forecoxa for 25–40 s. Such wasps then grasped the grasshopper’s antennae with their mandibles and began transport to the nest on the ground. A fifth female paused three times during transport to apply her mandibles to the base of the prey’s forecoxa for 25–50 s. Wasps took from 5.5 min to 2.5 h to hunt for and subdue prey and return to their burrow. Prey transport More than 150 females were observed transporting prey forward on the ground. Even wasps carrying small grasshoppers (wasp weight = 24 mg, prey weight = 38 mg) made no attempt to fly. All but four females held the paralyzed grasshopper ventral side upward all the way to the nest. Four wasps carried the prey dorsal side upward for 10–30 cm, then switched it 2008 F.E. Kurczewski 49 to a ventral side up position before proceeding farther. Females grasped the grasshopper’s antennae with their mandibles and held the sides of its body Figure 7. Tachysphex pechumani female transporting nymphal Chloealtis conspersa forward on sand. Wasp’s mandibles and hindlegs are grasping grasshopper’s right antenna and sides of thorax, respectively. Grasshopper’s left antenna is laid back under wasp’s mid- and hindlegs beside her abdomen. Figure 8. Tachysphex pechumani female kneading soft intersegmental membrane around base of nymphal Chloealtis conspersa foreleg with mandibles. 50 Northeastern Naturalist Vol. 15, Monograph 2 with their hindlegs (Fig. 7). Larger and heavier prey were straddled more anteriorly and grasped with the mandibles farther out on the antennae. The female’s first and second pairs of legs were used for walking or running. Her wings beat continually to assist the forward thrust and her antennae were constantly waved. A wasp astride prey proceeded to her nest in a series of rushes, 2–8 cm long, interspersed with frequent pauses. During pauses, the female infrequently cleaned her antennae with her forelegs and, sometimes, appressed her mouthparts to the soft intersegmental membrane surrounding the base of the grasshopper’s foreleg (Fig. 8). One wasp, circling constantly, took 32 min to transport her prey a distance of only 4 m. She continually paused, cleaned herself, and appressed her mouthparts to the base of the grasshopper’s foreleg. Other females spent 1–13 min (mean = 7.2 ± 4.0, N = 12) to transport prey 1–16 m (mean = 3.8 ± 2.2, N = 12). While most wasps proceeded forward in a straight line, some transport involved circling, pausing, releasing the prey, antennal cleaning, flights to nearby vegetation, and appressing the mouthparts to the base of the grasshopper’s foreleg. One female with prey escaped the pursuit of three satellite-flies (Sarcophagidae: Miltogrammini) by climbing a plant, clinging to the stem with the mid- and hindlegs, and remaining motionless except for slowly waving the antennae. This wasp periodically cleaned her antennae and mouthparts, but otherwise remained still. When startled, some females in transport raised their wings above the dorsum and held them in an elevated position for a few to several seconds. Other wasps flew off the prey and landed on the sand facing the intruder. After the disturbance subsided several seconds or minutes later, they remounted the grasshopper and resumed transport to the nest. Nest entry A female released her paralyzed grasshopper with its head near the entrance. However, the longitudinal axis of the prey’s body was oriented variously with respect to the direction of the burrow. More prey (72) were placed below the entrance than above it (46) or beside it (7). Prey placed at an extreme angle to the direction of the burrow somersaulted when pulled inside by the wasp through the mechanics of dragging the grasshopper inside. Females, using their forelegs in unison, spent 17–60 s (mean = 37.3 ± 18.0, N = 11) to remove the loose sand fill from an entrance. They took less time to open an entrance at higher sand surface temperatures and more time to remove the fill at lower sand surface temperatures (Fig. 9). A wasp kept her wings flat on the dorsum and raised her abdomen synchronously with the digging forelegs as she removed the sand fill. Some females backed onto the tumulus with loads of sand three or four times when removing the fill. After opening an entrance a female entered the burrow headfirst, turned around inside, reappeared headfirst in the opening 5–25 s later, and walked to the grasshopper. She grasped the prey’s antenna with the mandibles and 2008 F.E. Kurczewski 51 dragged the grasshopper backward into the burrow or repositioned it, entered the burrow, reappeared headfirst, and pulled in the grasshopper. One large prey (weight = 226 mg) became wedged in the entrance, forcing the female to abandon the grasshopper and the nest. Prey stealing was observed seven times during nest entry. The nests of the females involved were less than 1 m apart. If a resident female detected an intruding wasp, she attacked it, biting it with her mandibles and seizing it with her legs. In two cases, a larger intruding female defeated the smaller resident wasp and stole the prey. Three times the paralyzed grasshopper was circled once or twice by an intruding wasp, pounced on, and stung in the underside of its thorax. In all three cases, the resident wasp was inside her burrow and out of sight. One resident emerged from her burrow, grasped the grasshopper by its antenna with the intruder still atop it, and began pulling it backward into her nest. The second wasp flew off the grasshopper onto the tumulus, and the two females fought for 3 s before the intruder flew away. The resident then pulled the prey into the burrow, presumably oviposited, and completed her nest. Final closure Females appeared headfirst in their entrances from 10 s to 3.5 min after dragging in prey and presumably ovipositing. Some wasps then turned 180° Figure 9. Tachysphex pechumani opening temporary closure duration plotted against sand surface temperature. 52 Northeastern Naturalist Vol. 15, Monograph 2 on the tumulus and entered the opening before reappearing in the entrance to fill the burrow. Other females walked onto the tumulus (Fig. 10), flung sand backward into the burrow with the forelegs while backing in, and tamped the fill with the end of the abdomen. As a wasp progressively filled her burrow, she came outside more frequently to get loose sand from the tumulus. The distances to which she went to obtain sand remained about the same during the early stages of closing, but, later, wasps went slightly farther to get soil. As a burrow was filled, females remained on the surface for increasingly longer periods of time throwing sand backward with the forelegs before backing into the opening. Wasps made 9–18 (mean = 12.4 ± 2.9, N = 21) trips onto the surface to get sand for closure. Some females made 1–5 hovering and turning flights interspersed with filling burrows at sand surface temperatures of 40–56 °C. Only the proximal portion of the tumulus was used for fill. A female obtained additional soil by digging shallow pits, 8–20 mm deep, in front of her entrance. The distal part of the fan-shaped tumulus remained intact on the surface as darker colored, charcoal-laced sand. The shallow pits were later filled with sand as the wasp smoothed over the area of the entrance. Prior to finishing, some wasps turned around, faced toward their burrows, and made several hovering and turning flights above the area. After filling the burrow, wasps attempted to cover all traces of the entrance by walking in various directions while flinging sand backward with the forelegs. They spent from 14 s to 3.5 min for this behavior, antennal cleaning, and hovering and turning flights. Some females then placed tiny Figure 10. Tachysphex pechumani female walking forward to rake back sand into burrow with forelegs during final nest closure. Mid- and hindlegs are used for walking. 2008 F.E. Kurczewski 53 twigs, leaves, mosses, dried florets, and pebbles up to 2–4 mm in diameter on the fill with their mandibles and forelegs. Antennal cleaning, inspection of the area, and 1–4 s hovering and turning flights followed this behavior. Wasps then made several second-long circular or ovoid flights above the area before flying away. They averaged 11.8 ± 6.6 min (range = 6–33, N = 21) to fill their burrows and smooth over the area before leaving. There was a slight correlation between duration of final closure and burrow length (Fig. 11). There was no correlation between duration of final closure and sand surface temperature (R2 = .006, P = 0.77). Most wasps returned to the vicinity of their recently finished nest many minutes or hours later and started a new burrow. Eight females excavated, provisioned, and closed two nests in a single day. Nest structure and dimensions Nests were relatively short, shallow and single-celled. Nearly all burrows entered the soil obliquely in a straight direction at ca. 22.5–50° angles with the surface. A few burrows exhibited lateral curvature to by-pass underground stones or rootlets. Burrows were rather uniform in diameter regardless of soil compactness (mean = 6.4 ± 0.5 mm, range = 5–6, N = 18). The circular or ovoid entrances were generally larger in diameter (mean = 7.4 ± 1.2 mm, range = 5–10, N = 58) than the burrows, Figure 11. Tachysphex pechumani final closure duration plotted against burrow length. 54 Northeastern Naturalist Vol. 15, Monograph 2 although some were the same size. Entrances in looser sand were larger in diameter (mean = 8.2 ± 0.9 mm, range = 7–10, N = 35) than entrances in more compact sand (mean = 6.3 ± 0.6 mm, range = 5–7, N = 23) (P = 0.001, df = 55). Burrows were significantly longer in southern New Jersey (mean = 55.4 ± 5.8 mm, range = 44–69, N = 26) than in the central Great Lakes Region (mean = 46.6 ± 8.6 mm, range = 28–88, N = 201) (t = 6.81, P = 0.001, df = 40; Table 3). Burrows were significantly longer at southerly than northerly locations in the central Great Lakes Region (R2 = 0.65, P = 0.001, N = 201). Burrows were significantly longer with more precipitation (R2 = 0.45, P = 0.006) and warmer temperatures (R2 = 0.66, P = 0.001). There was variation in mean burrow length between some sites in the central Great Lakes Region (Table 3). There was annual variation in mean burrow length at certain sites: Allegan SGA (1991 vs. 1992, 1993, P = 0.001); Alger Cemetery, MI (1993 vs. 1994, P = 0.001); CFB Borden (1997 vs. 1996, 1998, 1999, P = 0.001) (Table 3). Burrows in looser sand (mean = 52.0 ± 7.6 mm, range = 35–88, N = 139) were longer than burrows in more compact sand (mean = 40.8 ± 5.6 mm, range = 28–56, N = 85) (P = 0.001, df = 214; Table 3). Cells were not significantly deeper in southern New Jersey (mean = 26.4 ± 3.2 mm, range = 21–34, N = 26) than in the central Great Lakes Region: (Mean = 25.5 ± 5.8 mm, range = 15–43, N = 201) (t = 1.32, P = 0.195, df = 49; Table 4). Cells were significantly deeper at southerly vs. northerly sites in the central Great Lakes Region (R2 = 0.48, P = 0.004, N = 201). Cells were not deeper with more precipitation (R2 = 0.21, P = 0.086), but were deeper with warmer temperature (R2 = 0.48, P = 0.004). There was variation in mean cell depth between some localities in the central Great Lakes Region (Table 4). There was annual variation in mean cell depth at certain sites: Allegan SGA (1991 vs. 1992, 1993, P = 0.001); Alger Cemetery (1993 vs. 1994, P = 0.001); CFB Borden (1997 vs. 1996, 1998, 1999, P = 0.002) (Table 4). Cells in looser sand (mean = 27.9 ± 5.1 mm, range = 20–43, N = 139) were deeper than cells in more compact sand (Mean = 21.9 ± 4.0 mm, range = 15–42, N = 85) (P = 0.001, df = 208; Table 4). Cells were elongate-ovoid in shape with some variation in height (mean = 6.6 ± 1.0 mm, range = 5–8, N = 141) and considerable variation in length (mean = 16.0 ± 4.0 mm, range = 10–20, N = 144). Cell length was barely correlated with prey size (wet weight) (Fig. 12). Prey Prey Acrididae consisted of 211 nymphal Melanoplus species, five adult male M. sanguinipes (Fabricius) (Melanoplinae), and 25 nymphal Chloealtis conspersa Harris (Gomphocerinae). There was regional and locality variation in the species and genera captured and stored in the cells. Prey Melanoplus from New Jersey included M. eurycerus Hebard, M. fasciatus (F. Walker), and M. impucidus Scudder. June cells from Indiana, Ohio, southern Lower Michigan, and Norfolk County, ON contained Chloealtis conspersa, 2008 F.E. Kurczewski 55 Melanoplus bivittatus, M. sanguinipes, M. viridipes Scudder, and M. spp. (undetermined). Early June cells from this region held mainly Melanoplus Table 3. Burrow length (mm), including cell length, of Tachysphex pechumani nests. Abbreviations: CFB = Canadian Forces Base, MT = Manestar Tract, NF = National Forest, SF = State Forest, SGA = State Game Area, SRA = State Recreation Area, TPT = Turkey Point Tract, UMBS = University of Michigan Biological Station, and WMA = Wildlife Management Area. Locality No. Range Mean ± S.D. Pine Township, IN 5 44–62 53.4 ± 7.54 Allegan SGA, MI (1991) 26 38–88 59.2 ± 7.70 Allegan SGA, MI (1992) 14 43–57 49.7 ± 4.68 Allegan SGA, MI (1993) 8 42–51 46.0 ± 3.51 Allegan SGA, MI (1994) 1 35 35.0 Manistee NF, MI (A, 1991) 2 45–55 50.0 ± 7.07 Manistee NF, MI (B, 1991) 4 28–37 33.0 ± 3.92 Manistee NF, MI (B, 1992) 6 32–44 39.0 ± 4.10 Manistee NF, MI (C, 1993) 1 41 41.0 Manistee NF, MI (D, 1993) 1 43 43.0 Manistee NF, MI (E, 1994) 4 45–65 53.5 ± 8.35 Au Sable SF, MI (1992) 10 33–49 41.1 ± 6.08 Au Sable SF, MI (1993) 5 38–42 40.0 ± 1.58 Houghton Lake SF, MI 6 41–51 46.0 ± 3.90 UMBS, MI 6 37–47 41.5 ± 3.56 Alger Cemetery, MI (1993) 4 29–40 35.5 ± 5.07 Alger Cemetery, MI (1994) 5 45–56 49.2 ± 4.66 Huron NF, MI (A, 1993) 4 37–42 39.0 ± 2.16 Huron NF, MI (B, 1994) 6 45–55 48.8 ± 4.22 Kalkaska SF, MI 1 37 37.0 Thunder Bay River SF, MI 2 39–41 40.0 ± 1.41 Luther Valley Cemetery, MI 3 34–43 37.7 ± 4.73 Pines Point SRA, MI 1 45 45.0 Barry SGA, MI 1 39 39.0 Hardwood SF, MI 1 46 46.0 Tittabawassee River SF, MI 1 51 51.0 Island Lake SRA, MI 1 42 42.0 Oak Openings Preserve, OH 4 37–61 51.0 ± 10.20 Mescher Road, OH 8 47–56 50.9 ± 2.90 St. Williams Forest TPT, ON 21 37–59 47.1 ± 6.57 St. Williams Forest MT, ON 1 49 49.0 Pinery Provincial Park, ON 1 40 40.0 Watson Property, ON 2 46–48 47.0 ± 1.41 Karner Blue Sanctuary, ON 4 43–50 46.5 ± 3.11 CFB Borden, ON (A, 1996) 9 32–48 37.6 ± 5.15 CFB Borden, ON (B, 1997) 4 51–57 53.8 ± 2.77 CFB Borden, ON (C, 1998) 15 36–53 42.7 ± 5.65 CFB Borden, ON (D, 1999) 3 35–39 37.3 ± 2.12 Wharton SF, NJ (1995) 2 54–56 55.0 ± 1.41 Wharton SF, NJ (1996) 6 54–69 58.5 ± 5.89 Bass River SF, NJ 1 44 44.0 Lebanon SF, NJ 8 48–68 57.9 ± 6.13 Galloway Township, NJ 2 52–58 55.0 ± 4.24 Chatsworth Woods, NJ 2 54–57 55.5 ± 2.12 Hammonton Creek WMA, NJ (1997) 4 48–54 50.3 ± 2.63 Hammonton Creek WMA, NJ (1998) 1 51 51.0 56 Northeastern Naturalist Vol. 15, Monograph 2 sanguinipes. Chloealtis conspersa and other species of Melanoplinae were added later in the month. Late June and July cells from central and northern Table 4. Cell depth (mm), including cell height, of Tachysphex pechumani nests. Abbreviations: CFB = Canadian Forces Base, MT = Manestar Tract, NF = National Forest, SF = State Forest, SGA = State Game Area, SRA = State Recreation Area, TPT = Turkey Point Tract, UMBS = University of Michigan Biological Station, and WMA = Wildlife Management Area. Locality No. Range Mean ± S.D. Pine Township, IN 5 26–38 31.6 ± 4.77 Allegan SGA, MI (1991) 26 21–43 33.5 ± 6.59 Allegan SGA, MI (1992) 14 23–33 26.6 ± 3.13 Allegan SGA, MI (1993) 8 22–32 25.3 ± 3.37 Allegan SGA, MI (1994) 1 22 22.0 Manistee NF, MI (A, 1991) 2 30–35 32.5 ± 1.73 Manistee NF, MI (B, 1991) 4 17–21 19.3 ± 2.04 Manistee NF, MI (B, 1992) 6 16–24 20.3 ± 3.14 Manistee NF, MI (C, 1993) 1 24 24.0 Manistee NF, MI (D, 1993) 1 25 25.0 Manistee NF, MI (E, 1994) 4 28–30 28.8 ± 0.91 Au Sable SF, MI (1992) 10 15–25 20.0 ± 3.68 Au Sable SF, MI (1993) 5 23–27 24.5 ± 1.52 Houghton Lake SF, MI 6 19–24 24.0 ± 2.28 UMBS, MI 6 18–25 20.3 ± 2.50 Alger Cemetery, MI (1993) 4 15–19 18.0 ± 2.00 Alger Cemetery, MI (1994) 5 26–42 31.8 ± 6.34 Huron NF, MI (A, 1993) 4 21–25 23.3 ± 1.70 Huron NF, MI (B, 1994) 6 24–29 26.7 ± 1.95 Kalkaska SF, MI 1 18 18.0 Thunder Bay River SF, MI 2 23–24 23.5 ± 0.71 Luther Valley Cemetery, MI 3 17–22 19.7 ± 2.52 Pines Point SRA, MI 1 25 25.0 Barry SGA, MI 1 25 25.0 Hardwood SF, MI 1 21 21.0 Tittabawassee River SF, MI 1 24 24.0 Island Lake SRA, MI 1 24 24.0 Oak Openings Preserve, OH 4 24–32 28.3 ± 3.30 Mescher Road, OH 8 23–33 28.8 ± 3.69 St Williams Forest TPT, ON 21 20–35 24.6 ± 3.29 St Williams Forest MT, ON 1 27 27.0 Pinery Provincial Park, ON 1 23 23.0 Watson Property, ON 2 25–26 25.5 ± 0.71 Karner Blue Sanctuary, ON 4 20–25 22.8 ± 2.22 CFB Borden, ON (A, 1996) 9 18–25 20.3 ± 2.45 CFB Borden, ON (B, 1997) 4 29–33 31.3 ± 1.68 CFB Borden, ON (C, 1998) 15 18–28 22.9 ± 2.85 CFB Borden, ON (D, 1999) 3 20–21 20.3 ± 0.58 Wharton SF, NJ (1995) 2 24–25 24.5 ± 0.71 Wharton SF, NJ (1996) 6 23–30 27.7 ± 2.49 Bass River SF, NJ 1 24 24.0 Lebanon SF, NJ 8 21–34 25.6 ± 4.21 Galloway Township, NJ 2 28–29 28.5 ± 0.71 Chatsworth Woods, NJ 2 26–33 29.5 ± 4.95 Hammonton Creek WMA, NJ (1997) 4 24–25 24.8 ± 0.50 Hammonton Creek WMA, NJ (1998) 1 28 28.0 2008 F.E. Kurczewski 57 Lower Michigan and Lambton and Simcoe counties, ON contained mainly Melanoplus species, including M. bivittatus and M. sanguinipes, except for Chloealtis conspersa in three cells at CFB Borden. The number of prey placed in a cell for larval food was invariably one. The mean weight of the grasshopper, which was often much larger and heavier than the wasp, was 140.1 ± 39.6 mg (range = 38–195, N = 21) in New Jersey, and 132.7 ± 46.1 mg (range = 41–262, N = 163) in the central Great Lakes Region. The mean wasp weight was 29.5 ± 8.4 mg (range = 24–42, N = 4) in New Jersey, and 30.7 ± 6.4 mg (range = 17–48, N = 60) in the central Great Lakes Region. The mean ratio of prey to wasp wet weight was 4.75:1 (range = 1.58–7.08:1, N = 4) in New Jersey, and 4.39:1 (range = 2.28–7.71:1, N = 60) in the central Great Lakes Region. Larger wasps tended to capture larger prey (Fig. 13). The majority of prey (232/247 or 93.9%) was positioned in the cell head inward and ventral side upward (Fig.14); 15 (6.1%) grasshoppers were placed in cells head inward and on the left or right side. Twelve (4.9%) prey had a hindleg missing. Larger acridids had their hindlegs extending 4–8 mm into the burrow in front of the cell. Egg Wasp eggs were cream-colored, sausage-shaped, slightly curved, and elastic. Live eggs were 2.0–2.5 mm long and 0.5–0.6 mm wide. An egg was Figure 12. Tachysphex pechumani cell length plotted against prey (wet) weight. 58 Northeastern Naturalist Vol. 15, Monograph 2 Figure 13. Tachysphex pechumani prey (wet) weight plotted against wasp (wet) weight. Figure 14. Exposed nest of Tachysphex pechumani (side view) showing paralyzed immature Melanoplus sp. positioned head inward and ventral side upward in the cell. 2008 F.E. Kurczewski 59 affixed by its less-tapered distal end to the soft intersegmental membrane surrounding the base of a procoxa and placed transversely across the prey’s pro- and mesosterna. Some wasps tended to affix an egg consistently to one side or the other of successive prey. However, there was no preference toward left- or right-sided affixation in a region or at a locality. In New Jersey, 12 eggs were equally affixed to the left or right basal forecoxal intersegmental membrane. In the central Great Lakes Region, 103 (52.0%) eggs were attached to the intersegmental membrane of the left forecoxal base, and 95 (48.0%) eggs were fixed to that of the right forecoxal base. In larger aggregations, eggs were affixed about equally to the prey’s left or right forecoxal base; in 1991 at Allegan SGA, 12 were affixed to the left, and 13 to the right, and in 1996 at St. Williams Crown Forest Turkey Point Tract 10 were affixed to the left and 11 to the right. Enemies Twenty-eight of 247 (11.3%) fully provisioned cells contained scavenging ants (Formicidae) or cleptoparasitic Chrysididae (Hymenoptera) or Miltogrammini (Diptera). The highest mortality rates were at Pine Township, IN (2/5 cells or 40.0%), Allegan SGA in 1992 (5/14 cells or 35.7%), and St. Williams Crown Forest Turkey Point Tract in 1996 (5/21 cells or 23.8%). Six cells at five localities were infested with foraging ants of the Tribe Lasiini (Formicidae). Three and eight Acanthomyops claviger (Roger), respectively, were recovered from two finished T. pechumani nests at the Allegan SGA in 1991. When the cells were unearthed, the ants were amputating and carrying away pieces of the paralyzed grasshopper. There was no evidence of the wasp’s egg in either cell. Female Hedychridium fletcheri Bodenstein (Chrysididae) were observed at the Allegan SGA in 1991 making short flights just above the sand surface, landing, and running rapidly in small circles near temporarily filled T. pechumani entrances. They lurked nearby on the sand or entered partly open nests, exiting seconds or minutes later. This cuckoo-wasp waited for a female T. pechumani to remove the sand fill and pull the grasshopper inside. She then followed the host wasp down the burrow, remained below ground for a minute or longer, and exited headfirst before the T. pechumani began to fill the burrow with soil. Two finished T. pechumani nests each contained a small (<1 mm long), ovoid, presumably H. fletcheri egg lying loosely on the grasshopper’s abdominal sternite. Each nest also had a 2.0–2.5 mm long T. pechumani egg affixed securely across the prey’s pro- and mesosterna. Twenty cells at 10 localities held from two to four maggots of the tribe Miltogrammini (Sarcophagidae). Provisioning wasps were trailed to their nests by one or more satellite-flies: Sphixapata rubriventris (Macquart), S. vigilans (Allen), or S. trilineata (Wulp). One S. rubriventris perched near a wasp nest, periodically flying to and landing on the tumulus, but she did 60 Northeastern Naturalist Vol. 15, Monograph 2 not larviposit in the entrance (Fig. 15). Another S. rubriventris followed a provisioning wasp into her entrance and larviposited. Females of S. vigilans larviposited on the abdominal sternites of grasshoppers as they were taken into nests. Larviposition on the prey’s abdominal sternites by S. trilineata and S. vigilans occurred during transport. The miltogrammines Sphenometopa tergata (Coquillett) and Taxigramma heteroneura Meigen were also attracted to wasps transporting prey. One S. tergata female pursued a provisioning wasp for 1.3 m, flying from grass blade to grass blade. She followed the wasp to the nest, waited until the prey was dragged in, and larviposited in the burrow. Three such flies pursued another provisioning wasp to her nest, but only one fly larviposited in the burrow. Three other S. tergata followed a provisioning wasp for 17 min, after which the female abandoned her prey on the sand. The flies showed no interest in the abandoned grasshopper. Three S. tergata attended an excavating wasp, remaining near her entrance until she returned with prey. Two of the flies then larviposited in the entrance as the grasshopper was pulled down the burrow. One provisioning wasp was pursued by two T. heteroneura. She repeatedly released her prey and flew at the flies, momentarily chasing Figure 15. Sphixapata rubriventris or S. vigilans female perched on plant stem overlooking Tachysphex pechumani nest entrance. 2008 F.E. Kurczewski 61 them away. The wasp eventually eluded the flies by stopping in the shade beneath a plant and remaining motionless atop the grasshopper for several minutes. A third T. heteroneura pursued a wasp transporting prey across the sand. The fly flew onto the grasshopper’s abdominal sternites and remained there during transport. At the entrance, the fly flew off the prey, stood motionless next to the opening, and larviposited in the entrance as the grasshopper was pulled inside. Discussion Tachysphex pechumani is a unique species in the genus from the standpoint of external morphology, nesting behavior, ecology, and geographic and seasonal distribution (Kurczewski 1987a, 1998, 2008; Kurczewski and Elliott 1978; Kurczewski et al. 1970; Moan and Tramer 2008; Pulawski 1988). It can be readily separated from other nearctic Tachysphex on the basis of its long, mainly orange antennae that the females constantly wave when nesting. Antenna waving is unknown in other Tachysphex that have dark, shorter antennal segments. Females of T. pechumani begin burrows at air and sand surface temperatures as low as 18 and 24 °C, respectively, and usually leave the nesting area when surface temperature approaches 55 °C. Tachysphex pompiliformis (Panzer), a holarctic species in the pompiliformis species group, nests in Idaho at air temperature as low as 7.8 °C (46 °F) (Newton 1956). Females of the nearctic T. tarsatus (Say), also in the pompiliformis group, withstand night temperatures as low as 1 °C inside their burrows (Kurczewski 1991). Tachysphex tarsatus provisions at an air temperature as low as 19 °C. At the other extreme, some females of T. similis Rohwer and T. terminatus (Smith), both in the terminatus species group, often nest through the hottest hours of the day at surface temperatures as high as 63 and 65 °C, respectively (F.E. Kurczewski, pers. observ.). Bimodality in T. pechumani nesting occurs on hot days with maximal activity in late morning and a secondary peak in mid- to late afternoon. This pattern implies that the species is ill suited to withstand the prolonged high temperatures under which many of its congeners nest in the west-central and southwestern US (Kurczewski 1998). Karsai (1989) found in Hungary that diurnal activity in the crabronid Bembecinus tridens (Fabricius) and the pompilid Pompilus cinereus (Fabricius) is unimodal on cooler days and bimodal on hotter days, with maximal activity in mid- to late morning. Hager and Kurczewski (1986) noted peak nesting activity of the nearctic sphecid Ammophila harti (Fernald) in late morning, with a hint of bimodality in second generation wasps. Tachysphex similis and T. terminatus, like A. harti, nest in bare sand, but rarely demonstrate distinct bimodality in nesting on hot days. Many females provision continually from mid-morning to late afternoon, bringing into their nests as many as 33 and 23 consecutive prey 62 Northeastern Naturalist Vol. 15, Monograph 2 items in 4 and 5 h, respectively, at sand surface temperatures of 55–61 °C (F.E. Kurczewski, pers. observ.). Unlike T. pechumani that practices ground transport of large prey, both T. similis and T. terminatus nearly always transport small prey in flight. Tachysphex pechumani has a single adult emergence annually in late spring–early summer (Kurczewski and Elliott 1978, Kurczewski et al. 1970). One generation per year and only four to five weeks’ flight season may seem restrictive, particularly in southern New Jersey where at least four months of suitable weather are available for additional generations of wasps. Such a narrow time window may reflect a past period when optimal climatic conditions were more abbreviated or climate was hot, droughty, and unfavorable for nesting in mid- to late summer. The univoltine life cycle of T. pechumani is coincident with maximal amount of daylight surrounding summer solstice, reduced natural fire frequency in late spring–early summer, and an abundance of suitable-sized grasshopper prey (Kurczewski 1998). Tachysphex acutus (Patton), T. tarsatus, T. similis, and T. terminatus are common species in the same geographic region as T. pechumani and emerge at the same time of year, but have two generations in late spring and mid- to late summer. The last three species demonstrate wider variability in nesting sites and capture a much broader range of prey species than T. pechumani (Kurczewski 1991; F.E. Kurczewski, pers. observ.). Recently emerged females of T. pechumani are observed in early August in northern Lower Michigan. They excavate burrows, but do not capture prey or nest, are not accompanied by males, and are probably accidental emergents. Such emergents are seen occasionally in univoltine, ground-nesting solitary bees where a portion of the mature first-generation larvae does not spin a cocoon, but immediately pupates and emerges. Most late emergents are unsuccessful as they do not nest or overwinter, but simply die without leaving any progeny (Neff and Simpson 1992). Females often raise their wings above their dorsum for a second or two before beginning a burrow. Wing elevation may be a precursor to the hovering and turning flights made during the initial stages of excavation. Such flights into cooler strata of air enable the wasps to avoid high sand temperatures and may familiarize them with their surroundings to facilitate subsequent prey transport. Females of T. terminatus make similar hovering flights to avoid the hot sand when surface temperature exceeds 54 °C (F.E. Kurczewski, pers. observ.). An unusual behavior exhibited by females of T. pechumani is climbing vegetation and assuming a stationary position with the axis of the body parallel or nearly perpendicular to that of the plant stem. The wasp grasps the stem with her mid- and hindlegs, dangles her forelegs, and waves her antennae or holds them motionless, nearly touching, and straight outward (Kurczewski and Elliott 1978). The significance of this behavior is unknown aside from enabling the wasp to avoid the hot sand surface and escape the constant harassment of satellite-flies. 2008 F.E. Kurczewski 63 Females of T. pechumani are rarely exposed on the surface when removing sand from the burrow during excavation, backing from the entrance the length of the body or less, or remaining below ground and flinging sand from the opening. This genus-atypical method of sand removal results in a flattened, fan-shaped, charcoal-laced dark tumulus on a lighter surface background. No nearctic Tachysphex has been reported to demonstrate this manner of burrow excavation or tumulus configuration. Most species in the Tachysphex terminatus group spend several minutes per burrow excavation on the sand surface leveling the tumulus prior to making a temporary closure of the nest entrance (F.E. Kurczewski, pers. observ.). Tachysphex pechumani is the only nearctic species in the large pompiliformis group known to temporarily close the entrance, albeit loosely, before hunting for prey (Kurczewski 1987a). A temporary closure, even loose and incomplete, deters certain enemies from entering the nest. There may be a cryptic relationship between nesting in bare sand, temporary closure of the entrance, and the telltale dark-colored tumulus in T. pechumani. Other nearctic species in the pompiliformis group do not temporarily close the entrance and nest among or near vegetation or beneath stones (Kurczewski 1987a; Kurczewski and Kurczewski 1987; F.E. Kurczewski pers. observ.). These species may use the open entrance and prominent mound of soil from burrow excavation or certain stones as landmarks when they return to the nest with prey. In T. pechumani, the temporary closure becomes increasingly loose or non-existent with rising sand surface temperature, especially above 50 °C. Tachysphex similis and T. terminatus also make temporary closures and they leave the entrance partly or nearly fully open at very high sand surface temperature (>60 °C)(F.E. Kurczewski pers. observ.). Even at lower sand surface temperatures (30–40 °C), T. pechumani temporary closures are depressed and often incomplete, whereas those of T. similis and T. terminatus are, more or less, filled flush with the surface and often indistinguishable from the surrounding sand. Females of T. pechumani hunt for prey not far from their nests, thereby facilitating the often slow and tedious transport of large grasshoppers. Prey capture involves the wasp waving her antennae while facing and circling the grasshopper. After making a nearly complete or full circle, she pounces on the grasshopper and stings it in the underside of its thorax near a leg base. Females may circle the prey one or more times in clockwise and/or counterclockwise directions. In T. coquilletti Rohwer, a nymphal mantid hunter in the julliani species group, females fly in circles in front of the prey until it stops following the wasp’s flight movements at which time the wasp attacks (Alcock and Gamboa 1975). Circling behavior has not been described for other nearctic Tachysphex that prey upon grasshoppers; capture in these species is much more direct and rapid. Searching for prey among vegetation not far from the entrance and stocking only one relatively large grasshopper in a single-celled nest reduces the distance, duration, and repetition of prey transport. Such a method of 64 Northeastern Naturalist Vol. 15, Monograph 2 provisioning is commonly seen among species in the pompiliformis group (Kurczewski 1987a). In T. pechumani, staying below ground for most of final nest closure and using only the proximal portion of the tumulus for fill limits the female’s exposure on the bare sand surface. Other species in the pompiliformis group are often shielded among or beneath vegetation or stones during final nest closure (Kurczewski 1987a, Kurczewski and Kurczewski 1987). Unlike other nearctic Tachysphex, T. pechumani females demonstrate considerable variation in placement of prey near the entrance. They position the grasshopper’s body seemingly randomly at all angles on either side of the entrance above or below it with the head near the opening. Other Tachysphex place the prey below the entrance nearly always in a straight line with the direction of the burrow, the head being near the opening (F.E. Kurczewski pers. observ.). Because the distinctive fanshaped, dark-colored tumulus and depressed, often incomplete temporary closure possibly serve as beacons for nest finding, one might expect T. pechumani to display more, not less, rigidity in prey placement than some other species in which the tumulus and temporary closure are indistinguishable from the surrounding sand. Tachysphex pechumani preys on late instar nymphal or, rarely, adult gomphocerine and melanopline phytophilous grasshoppers, two groups that possess adhesive tarsal pads and frequent vegetation. Such limited prey capture correlates with hunting females running on plants and making winding, hovering, and turning flights among forbs and grasses. Tachysphex pechumani does not capture species of Oedipodinae, an acridid group that lacks adhesive tarsal pads and occurs on bare ground. Several species in the pompiliformis group capture a preponderance of Oedipodinae, sometimes on a seasonal basis, and they hunt this type of prey by running rapidly on the ground (Kurczewski 1987a, 1987b, 1991). Tachysphex pechumani preys on larger grasshoppers relative to its own size than most nearctic Tachysphex. Prey of the New Jersey females averages about five times as heavy as the wasp (Kurczewski and Elliott 1978), while that of the central Great Lakes Region females averages nearly that much . Tachysphex tarsatus, a similar-sized species in the northeastern US that also practices ground transport, uses prey that averages less than four times its weight in August–September, but much less than that in June–July (Kurczewski 1991). Tachysphex tarsatus has two generations per year in the Northeast. Tachysphex acutus, another eastern species, weighs only about half as much as T. pechumani or T. tarsatus, captures prey five to six times its weight, and nests in fields where it is inconspicuous during its slow and cumbersome ground transport (Kurczewski 1989). The nesting behavior of T. pechumani includes several components totally unlike those of nearctic congeners. In addition, other Tachysphex species are much more rapid in their movements and demonstrate fewer interruptions in nesting sequence related to high sand surface temperature. 2008 F.E. Kurczewski 65 Most other species of Tachysphex have more than one generation per year and, unlike T. pechumani, may nest through the hottest hours of the day. These life-history patterns have resulted in broader seasonal and geographic distribution and commoner occurrence throughout their ranges. For example, in Pulawski’s (1988) revision of the nearctic species of Tachysphex, he recorded the following number of museum specimens for some common eastern species: 2965 T. tarsatus, 1717 T. terminatus, and 1624 T. similis. In contrast, he reported only 131 specimens of T. pechumani. The continued existence of T. pechumani in the central Great Lakes Region and southern New Jersey, therefore, may hinge on its stringent climatic, edaphic, and ecological requirements as enumerated in the companion papers of this monograph (Kurczewski 2008, Moan and Tramer 2008). Acknowledgments Elliot Tramer, who kindly agreed to serve as manuscript editor, and two anonymous reviewers suggested changes that improved the manuscipt. Terry Crabe, Denise Gehring, Michelle Grigore, Bill Huff, John Lerg, and Mary Rabe assisted with facilities or funding. Matthias Buck, Bob Jacksy, Mark O’Brien, and Jeff Skevington added nesting behavior information. Irving Cantrall (deceased) and Dan Otte identified prey Acrididae samples. Hugh Boyle, Dana Bruington, Bob Jacksy, Keith Kurczewski, Mary Morlando, and Ed Stanton assisted with field studies. Dan Dindal and Don Bickelhaupt separated and analyzed New Jersey and Michigan soil samples, respectively. Erin Moan and Elliot Tramer agreed to publish their paper concurrently with mine in monograph format. Bob Jacksy provided the cover and other photographs except for Figure 14, which was supplied by Art Weber. Esther Clark formatted Figure 2. Don Artz formatted Figures 3 and 4. Steve Stehman and Liz Hassett furnished statistical analyses. Funds for this study were partly provided by the Michigan Chapter of The Nature Conservancy, Michigan Department of Natural Resources, Toledo Area Metroparks, and New York State United University Professions. Literature Cited Alcock, J., and G.J. Gamboa. 1975. 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