Leaf Diet Affects Growth of a Shredder, Limnephilus indivisus, from a Seasonal New England Pond
Scott D. Smyers, Brett A. Trowbridge, and Brian O. Butler
Northeastern Naturalist, Volume 18, Issue 1 (2011): 27–36
Full-text pdf (Accessible only to subscribers.To subscribe click here.)
Access Journal Content
Open access browsing of table of contents and abstract pages. Full text pdfs available for download for subscribers.
Current Issue: Vol. 30 (3)
Check out NENA's latest Monograph:
Monograph 22
2011 NORTHEASTERN NATURALIST 18(1):27–36
Leaf Diet Affects Growth of a Shredder, Limnephilus
indivisus, from a Seasonal New England Pond
Scott D. Smyers1,*, Brett A. Trowbridge1, and Brian O. Butler1
Abstract - Deciduous leaf litter is often a primary source of energy at the base of the food
web in seasonal woodland ponds (e.g., vernal or autumnal pools), which are common in
the northeastern United States. It is therefore important to understand how leaf diet affects
growth of detritivores, such as the caddisfly Limnephilus indivisus Walker, that feed
almost exclusively on submerged plant matter in seasonal pond systems. Growth may
relate to how rapidly a caddisfly is able to complete its larval development and pupate,
and hence its ability to survive in small ponds with short hydroperiods. Growth is also
related to the maximum size the larva achieves. In many organisms, attaining a larger
size conveys several distinct advantages: larger individuals typically have higher survival
rates and increased fecundity, and hence greater fitness compared to smaller conspecifics
or competing sympatric species. To assess how leaf diet influences the growth of larvae
of L. indivisus, we conducted a controlled experiment to test how different leaf diets influenced larval growth. The leaf diet experiment was set up as follows: Treatment 1: Acer
rubrum (Red Maple), Treatment 2: Quercus spp. (oak), and Treatment 3: Red Maple and
oak. L. indivisus that were fed oak leaves or a mix of oak and Red Maple leaves grew
significantly larger than larvae fed Red Maple leaves only. In Treatment 3, the caddisfly
was observed more frequently on the oak leaf compared to the Red Maple leaf. Although
L. indivisus selected oak leaves more often during the experiment, oak leaves were less
abundant than maple leaves at our study site. We hypothesize that the oak leaves provide
more nutrients to L. indivisus due to a combination of physical, biological, and chemical
properties which results in more larval growth.
Introduction
Dead leaves from trees and shrubs can provide considerable energetic input to
seasonal ponds (Bonner et al. 1997, Rubbo and Kiesecker 2004, Rubbo et al. 2006).
At the base of the aquatic food web, deciduous leaves decaying on the bottom of
a pond provide substrate and a direct nutrient source for zooplankton, fungi, and
bacteria. The physical characteristics of decomposing leaves influence the bacterial
and fungal communities that colonize the leaves (Gulis and Suberkropp 2003a,
Mille-Lindblom and Tranvik 2003), and these fungi and bacteria provide most of
the nutrients to detritivores, specifically shredders, such as caddisflies (Gulis and
Suberkropp 2003b, Wiggins 2002). Shredders play an important role in nutrient
cycling of seasonal pond ecosystems, both directly by transferring energy from decomposing
leaf litter to animal biomass and indirectly by breaking down leaves to
small particles that are more readily available to micro-organisms and filter feeders.
In Massachusetts, larval Limnephilus indivisus Walker caddisflies are particularly
common and often abundant within seasonal ponds (Colburn 2004). They are
most conspicuous in early spring because they construct portable cases using parts
1Oxbow Associates, Inc., PO Box 971, Acton, MA 01720. *Corresponding author -
smyers@oxbowassociates.com.
28 Northeastern Naturalist Vol. 18, No. 1
of leaves, stems, needles, and twigs. Limnephilus indivisus have a complex life
history. Eggs deposited by adults in the autumn hatch after the pond fills in the late
fall or early spring, then larvae feed principally on leaf litter and submerged vegetation
and are most active from ice melt (typically early April in Massachusetts)
until May–June (Colburn 2004, Wiggins 1973). Larvae pass through several instars
before they seal themselves in their cases and then undergo pupation and metamorphosis.
Adults emerge and breed during mid-late summer. Females deposit eggs
near or in a pond late in the fall (Wiggins 1973, 1996).
Changes in larval diet have been demonstrated to influence the life history
and fecundity of caddisflies that inhabit seasonal ponds in the mountains of the
western US (Jannot 2009, Jannot et al. 2007, Wissinger et al. 2004). The nutritive
quality and availability of food influence growth rate and fitness of caddisflies
(Anderson and Cummins 1979; Bärlocher et al. 1978; Hutchens et al. 1997; Otto
1974, 1983; Wiggins 2002). It is important to understand how different leaf litter
diets affect growth of larval caddisflies.
Hutchens et al. (1997) demonstrated that both the species of leaf and the time
that the leaf is “conditioned” by microbes after being submerged influences larval
growth rate of some caddisflies inhabiting headwater streams. If insect pests or
disease defoliates the trees, aquatic shredders that rely on submerged leaves can be
directly influenced (Hutchens and Benfield 2000). Further, caddisfly larvae can detect
nutritive differences of leaves and preferentially select leaves that are heavily
colonized by microbes and therefore have higher nutritional values (Inkley et al.
2008). The amount of leaf litter consumed and the subsequent decomposition of leaf
litter is dependent upon food quality (Anderson and Cummins 1979).
Considering results from the aforementioned experiments and Rubbo and
Kiesecker’s (2004) hypothesis that a substantial shift in the tree species composition
around a seasonal pond, particularly at the landscape level, can impact
the entire food web of seasonal pond systems, we tested how leaf diet influenced
caddisfly growth. We hypothesized that the assemblage of tree species within the
forest canopy and their relative proportions of litter deposited within a pond are
important to the productivity of the biota within a pond. We predicted that there is
a direct relationship between the type of litter input by the surrounding forest and
the food quality of leaf litter in a pond. To test our hypothesis, we investigated
the growth of L. indivisus in response to three different leaf diets using the two
most prevalent leaf species within our study pond.
Methods
To assess the influence of forest canopy composition on L. indivisus, we quantified distribution of leaves, by species, submerged in a seasonal pond. We also
conducted a laboratory experiment to test how restricting the larval diet to certain
leaf types influenced larval caddisfly growth. Our leaf-diet experiment used the
species of leaves that were most commonly found within the pond, including Acer
rubrum L. (Red Maple) and either Quercus rubra L. (Red Oak) or Q. velutina
L. (Black Oak), which are known to hybridize in the northeastern United States
(Voss 1996). For the purposes of this study, we refer to oaks from this group as
Quercus spp. (oak). We hypothesized that a diet that includes slow-decaying
2011 S.D. Smyers, B.A. Trowbridge, and B.O. Butler 29
oak leaves would result in a faster growth rate of caddisflies compared to a diet
restricted to Red Maple.
Field data collection
The study pond has no inlet or outlet and is located in a forested hillside east of
East Wachusett Brook in Princeton, Worcester County, MA. There is a periphery
of deciduous and coniferous trees, but the majority of the pond is without a high
canopy. The southern end of the pond is >1 m deep in the center and has an open
canopy, while the northern end extends into a forested swamp that is less than 1 m deep and
has a full canopy. The southern end of the pond contains a mix of emergent grasses,
sedges, shrubs, and saplings, while the northern end contains a swamp with a mix
of Red Maple and Tsuga canadensis L. (Eastern Hemlock). The pond typically fills
in late summer to early fall and does not dry out completely except during neardrought
conditions (based on 9 years of observations by S.D. Smyers).
On 21 April 2003, when the water level was near the average seasonal high,
we collected live L. indivisus (n = 120) opportunistically throughout the pond.
Limnephilus indivisus was identified based on case structure and larval characteristics
of specimens preserved prior to and at the end of the experiment, using
illustrations and descriptions by Wiggins (1996). On the same day, we also collected
pond-conditioned leaf litter (e.g., saturated and colonized with bacteria
and fungi) and determined the relative abundance of deciduous leaf species by
identifying 100 whole deciduous leaves and recording counts for each species at
five randomly selected locations within the pond. Caddisflies and leaf litter were
transported in plastic buckets containing pond water to our laboratory.
Leaf-diet experiment
At the laboratory, some of the transported pond water, all of the caddisflies,
and some whole leaves were kept in 3 aerated buckets (19 L) containing a mixture
of leaf species, maintained at 20 °C with a simulated photoperiod typical for this
latitude during this time of year (14:10 L:D), until we began the experiment on
23 April 2003. The experiment was conducted under the same photoperiod and
temperature conditions until 14 May 2003 (21 days). The remaining leaves were
stored in buckets containing pond water.
Prior to introducing the caddisflies to the experimental container, we used
calipers to measure the case to the nearest millimeter. The case construction of this
species allows for accurate measurements of case length because the structural
material is predominantly fastened perpendicular to the long axis of the body. The
central cylinder surrounding the larva normally has flat openings at the anterior and
posterior ends. The primary response variable was the growth of the caddisfly, as
determined by measuring the length of each individual’s case at the beginning and
at the completion of the experiment. Furthermore, at the end of the experiment, we
measured the body length of each larva, outside of its case. Using a general linear
model analysis of variance with Tukey multiple comparisons (MINITAB 12.1,
1998), we compared the difference between case length and total body length by
treatment. Because body length and case length are related, we set α = 0.025 for
growth comparisons.
Caddisflies were randomly assigned to one of three treatments, each of which
consisted of an opaque plastic cup (90 mm diameter x 112 mm tall) filled with
30 Northeastern Naturalist Vol. 18, No. 1
500 ml of previously aerated pond water. Each cup contained a single L. indivisus
and 1 leaf of Red Maple (Treatment 1, n = 30), 1 leaf of oak (Treatment 2, n =
30), or 1 leaf of Red Maple and 1 leaf of oak (Treatment 3, n = 30). Leaves were
selected randomly from our leaf storage bucket and all were inspected to ensure
they were positively Red Maple or oak, approximately the same size by species,
and in similar condition as approximated by appearance (e.g., stained black). The
use of two leaves in the mixed treatment versus one leaf in the single leaf species
treatment is not likely to have affected the growth because we replaced the
leaves ad libitum before leaves were entirely consumed/skeletonized (approximately
75% eaten). All experimental cups were inspected once per day between
0900 and 1800 h, during simulated daylight conditions when activity is expected
to be the highest (Bailey 1982). Water was replaced in each cup every 4 days
with pond water that had been aerated for at least 12 hours. We took qualitative,
observational count data on each replicate once per day for 21 days: specifically,
survival, active feeding on a leaf versus non-active, and, if feeding, on which
leaf. We also noted whenever a leaf needed to be replaced,
This experiment depended on the presumption that the case length was directly
related to body length. Therefore, at the conclusion of the experiment we
measured the case length of the remaining L. indivisus and carefully extracted
each individual from their case to compare the lengths of each individual’s body
to its case. Because caddisflies typically curl when extracted from their cases,
even when kept alive, we placed each individual on a dry Petri dish and used
forceps to gently nudge the larva until it crawled into a straight line so that an
accurate measurement of their body length could be obtained to the nearest mm.
Using a t-test, we found no significant difference in length of the case compared
to length of the body for L. indivisus (n = 62): x̅ body (± 1 SE) = 14.50 mm (± 0.30),
x̅ case = 14.37 mm (± 0.28), t = 0.65, P = 0.521. Therefore, we determined that
body size of L. indivisus was accurately estimated by measuring cases, thus providing
a non-destructive measure of size.
Results
Field data collection
The deciduous leaf count data indicated that Red Maple was the most common
species represented in the pond (x̅ = 55.8%), followed by oak (x̅ = 17.8%),
Betula allegheniensis Britton (Yellow Birch; x̅ = 16.4%), Populus tremuloides
Michaux (Quaking Aspen; mean = 3.4%), Ulmus americana L. (American Elm;
x̅ = 3.4%), Fagus grandifolia Ehrhart (American Beech; x̅ =1.6%), Hamamelis
virginianus L. (Witch Hazel; x̅ = 1.2%), and A. saccharum Marshall (Sugar
Maple; x̅ = 0.6%).
Leaf-diet experiment
Survival of caddisflies appears to have been influenced by leaf diet, as survivorship
was least for Red Maple (60%), intermediate for oak (67%), and highest for
oak and Red Maple (80%). The frequency of size classes, by length, of caddisfly
cases at the beginning of the experiment was not maintained at the end of the experiment,
indicating individual change in case length varies between individual
2011 S.D. Smyers, B.A. Trowbridge, and B.O. Butler 31
caddisflies, thereby inferring variability of leaf nutrition (Fig. 1). Caddisflies fed
a diet of oak leaves (n = 20, x̅ case length ± 1 SE = 3.75 mm ± 0.51) or a mix of oak and
Red Maple (n = 24, x̅ case length ± 1 SE = 3.33 mm ± 0.38) had significantly longer
cases (Figs. 2–3) than those fed a diet restricted to Red Maple (n = 18, x̅ case length ± 1
SE = 1.39 mm ± 0.40; df = 2, F = 8.0, P = 0.001). The total body length of surviving
caddisflies fed oak leaves (n = 20, x̅ body length ± 1 SE = 14.8 mm ± 0.42) or a mix of
oak and Red Maple (n = 24, x̅ body length ± 1 SE = 15.5 mm ± 0.51) was significantly
Figure 1. Frequency
of caddisfly larvae
in each of three leafdiet
treatments as a
function of total case
length (mm): A. Red
Maple, B. oak, and
C. oak and Red Maple.
Black bars represented
case length
at time 0, and white
bars are final case
length at the conclusion
of the experiment.
32 Northeastern Naturalist Vol. 18, No. 1
longer (Fig. 4) than those fed a diet restricted to Red Maple (n = 18, x̅ body length ± 1 SE
= 12.9 mm ± 0.44; df = 2, F = 8.0, P = 0.001).
The average percent observed feeding was almost exactly the same between
treatments: oak = 72.1%, oak and Red Maple = 71.4%, and Red Maple = 72.5%. In
Treatment 3, where the caddisflies were provided both Red Maple and oak leaves,
they were observed more frequently on the oak leaves (64%) compared to Red Maple
leaves (36%). Within the oak leaf treatment, a total of 7 leaves were replaced,
2 after 16 d, 4 after 18 d, and 1 after 21 d. In the oak and Red Maple leaf treatment,
we replaced 14 leaves in total, 8 after 18–20 d, including 6 oak and 2 maple leaves.
Subsequently, within 3 replicates where leaves were already replaced, we replaced
both oak and maple leaves (6 leaves total) on days 20–21, 5–6 d after the first leaf
replacement (double replacement). In the treatment containing Red Maple leaves
only, we replaced 7 leaves total, including 4 after 16 d, 1 after 18 d, 1 after 19 d, and
1 double replacement on day 20, 4 d after the first replacement
We documented 5 occasions (oak = 3, oak and Red Maple = 1, Red Maple
= 1) where caddisflies were observed outside of their case, but were later found
to be back in their case and feeding normally. In other instances, when caddisflies
were observed live outside their case, they were later found dead outside their
case (oak = 10, oak and Red Maple = 6, Red Maple = 12). These were the only
instances of mortality documented in our study. There were no observations of
pupation during the experiment.
Discussion
Limnephilus indivisus were significantly larger after being provided Oak
leaves or a mix of Oak and Red Maple leaves. The effects of these different
leaf diets will likely carry through to subsequent life phases given that growth
of larvae directly influences time to pupation, size at metamorphosis, and adult
Figure 2. Mean (± 1 SE) case length (mm) at the beginning and end of the leaf-diet experiment.
Black bars are case length at time 0, and white bars are final case length at the conclusion
of the experiment. Asterisks indicate significant differences between beginning and
end case length for oak and mixed oak and Red Maple leaves (*P = 0.001). NS indicates a
non-significant difference within the Red Maple treatment.
2011 S.D. Smyers, B.A. Trowbridge, and B.O. Butler 33
reproductive success (Jannot et al. 2007, Stearns 1992). We believe the qualitative
data collected during the experiment provides additional insight and basis for
further experiments on feeding behavior. Our data indicate a trend for preferred
selection of oak leaves by feeding caddisflies. When exposed to both oak and
Red Maple leaves, L. indivisus more often selected oak leaves, even though oak
leaves were less abundant than Red Maple leaves at our study site. This result is
in agreement with Inkley et al.’s (2008) observations that larvae displayed a preference
for leaves with higher nutritional values. Furthermore, the combination
Figure 3. Mean (± 1 SE) case growth (mm) at the beginning and end of the leaf-diet
experiment. Different letters above the bars indicate significant differences between experimental
treatments (P = 0.001).
Figure 4. Mean (± 1 SE) total body length (mm) of live larvae extracted from cases at the
end of the leaf-diet experiment. Different letters above the bars indicate significant differences
between body length (P = 0.001).
34 Northeastern Naturalist Vol. 18, No. 1
of oak and Red Maple resulted in the highest survival and total leaves consumed
through the duration of the experiment, suggesting that a mixed diet is likely the
most beneficial for survival and increases the rate of feeding, but not necessarily
growth. Caddisfly growth is influenced by nutritional composition of each leaf
type; both Red Maple and oak leaves may provide important, but different nutrients,
with larvae benefiting from the ability to select from both types to obtain
the most nutritious diet when both leaf types are available.
In addition to the different nutritional quality of oak or Red Maple leaves, the
structural integrity of the case constructed from different leaf species may affect
the growth of the case and larval caddisfly. However, because we measured the
actual body of the larvae at the conclusion of the experiment, we do not believe
this was an ecologically important variable in our experiment, but we cannot rule
out the possibility that the integrity of various leaf materials alone may indirectly
influence growth of larvae under certain environmental conditions.
Our study demonstrates that L. indivisus are capable of selectively feeding
on the leaves that ultimately result in greater growth, but will continue to
feed on less productive leaves when they are readily available. Any significant
changes in the relative species richness of leaf litter could directly impact the
feeding behavior, growth, and survivorship of larval L. indivisus. Furthermore,
the environment experienced by a larval caddisfly, including nutrition, has been
demonstrated to influence adult fecundity (Jannot 2009).
Although our study did not include any analyses to quantify fungi or bacteria
available or consumed by L. indivisus, we hypothesize that the oak leaves provide
higher quality or more abundant nutrients for shredders due to a combination
of physical and chemical properties, resulting in more growth. Other species of
deciduous leaves should be considered for future experiments to compare how
caddisflies are influenced by different species assemblages in representative
populations within North America. We did not know the exact conditioning time
of the leaves used in the experiment, but because we selected leaves at random
from the five locations within the study pond and then mixed them, we know the
leaves were equivalent to those available in situ; in this regard, our experiment
represents realistic, natural conditions.
We considered cutting the leaves to control for leaf area in each treatment.
However, the use of entire leaves provides what may be an important physical
property in the shape of the leaf. The use of two leaves in the mixed treatment
versus one leaf in the single leaf species treatment is not likely to have affected
the growth because we replaced the leaves ad libitum, and our results indicate
that the two-leaf treatments did not result in significantly greater growth compared
to the single-leaf oak treatment.
Future studies on caddisflies of seasonal ponds with different canopy composition
(e.g., Ulmus, Fagus, and Betula), including factors affecting decomposition
rates of leaves, will be particularly useful to determine mechanisms that influence
growth, food selection, and life history of caddisflies. Our results should encourage
other researchers to conduct additional laboratory experiments and study
caddisfly populations on a larger scale, within an entire pond, to determine how
their growth and life history are affected by shifts in environmental conditions
(e.g., temperature and hydroperiod) and leaf-litter composition. Other research has
2011 S.D. Smyers, B.A. Trowbridge, and B.O. Butler 35
addressed some of these questions, providing an excellent baseline of information
from which to build upon. For example, leaves that are inundated in a permanent or
semi-permanent pond are more nutritious for L. indivisus compared to leaves submerged
for a shorter duration (Inkley et al. 2008). Moreover, nutrition, pond depth,
and water temperature during larval development have been demonstrated to interact
to influence female fecundity and longevity of L. indivisus (Jannot 2009).
Limnephilid caddisflies are likely to be responsive to major changes in the
composition of the leaf-litter input because they depend on leaf litter for nutrients.
Any change in available nutrient quality, specifically leaf species, may affect the
growth of caddisflies, and thereby increase or decrease the rate of leaf degredation
into fine particles, which are a source of primary production within a pond. Thus,
caddisflies are likely to have a major influence on how energy is cycled within
seasonal ponds. Any changes to leaf availability that affect how fast caddisflies
grow will also affect how rapidly leaves are broken down into smaller particles.
The amount of leaf litter consumed, the growth rate of the larvae, and subsequent
decomposition of leaf litter is partially dependent on temperature (Cummins
1973). Our results suggest that a seasonal pond containing a large proportion of
oak leaves will produce larger caddisflies and will break down more leaves compared
to an equivalent pond with a small proportion of oak leaves. However, other
leaf species need to be examined to determine how they affect larval growth and
time to pupation. As the dominant trees within a forest community surrounding an
aquatic habitat change over time due to catastrophic weather events, forest clearing,
species-specific disease, insect pests, or changes in climate, the surrounding
vegetative input will affect seasonal pond ecosystems. Caddisflies are abundant
and important components of the food web, and our future research will aim to determine
how forests and their communities of dead leaves influence aquatic lentic
ecosystems through complex pathways with potentially profound consequences.
Acknowledgments
We thank three anonymous reviewers for suggestions and recommendations that
greatly improved this manuscript. We thank D. Chandler for discussions on caddisfly
biology and assistance with specimen identification.
Literature Cited
Anderson, N.H., and K.W. Cummins. 1979. Influences of diet on the life histories of
aquatic insects. Journal of Fisheries Research Board of Canada 36:335–342.
Bailey, P.C.E. 1982. Diel activity pattern in larvae of the Australian caddisfly
Helicopsyche murrumba Mosley (Trichoptera: Helicopsychidae). Journal of Entomology
21:247–250.
Bärlocher, F., R.J. MacKay, and G.B. Wiggins. 1978. Detritus processing in a temporary
vernal pool in southern Ontario. Archiv für Hydrobiologie 81:269–295.
Bonner, L.A., W.J. Diehl, and R. Altig. 1997. Physical, chemical, and biological dynamics
of five temporary dystrophic forest pools in central Mississippi. Hydrobiologia
353:77–89.
Colburn, E. 2004. Vernal Pools: Natural History and Conservation. McDonald and Woodward
Publishing Company, Blacksburg, VA. 426 pp.
36 Northeastern Naturalist Vol. 18, No. 1
Cummins, K.W. 1973. Trophic relationships of aquatic insects. Annual Review of Entomology
18:183–206.
Gulis, V., and K. Suberkropp. 2003a. Interactions between stream fungi and bacteria
associated with decomposing leaf litter at different levels of nutrient availability.
Aquatic Microbial Ecology 30:149–157.
Gulis, V., and K. Suberkropp. 2003b. Leaf litter decomposition and microbial activity in
nutrient-enriched and unaltered reaches of a headwater stream. Freshwater Biology
48:123–134.
Hutchens, J.J., Jr., and E.F. Benfield. 2000. Effects of defoliation by the Gypsy Moth on
detritus processing in southern Appalachian streams. American Midland Naturalist
143:397–404.
Hutchens, J.J., Jr., E.F. Benfield, and J.R. Jackson. 1997. Diet and growth of a leafshredding
caddisfly in southern Appalachian streams of contrasting disturbance history.
Hydrobiologia 346:193–201.
Inkley, M.D., S.A. Wissinger, and B.L. Baros. 2008. Effects of drying regime on microbial
colonization and shredder preference in seasonal woodland wetlands. Freshwater
Biology 53:435–445.
Jannot, J.E. 2009. Life-history plasticity and fitness in a caddisfly in response to proximate
pond-drying. Oecologia 161:267–277.
Jannot, J.E., E.B. Runeau, and S.A. Wissinger. 2007. Effects of larval energetic resources
on life history and adult allocation patterns in a caddisfly (Trichoptera: Phryganeidae).
Ecological Entomology 32:376–383.
Mille-Lindblom, C., and L.J. Tranvik. 2003. Antagonism between bacteria and fungi on
decomposing aquatic plant litter. Microbial Ecology 45:173–182.
Otto, C. 1974. Growth and energetics in a larval population of Potoamorphylax cingulatus
(Steph.) (Trichoptera) in a south Swedish stream. Journal of Animal Ecology
43:339–361.
Otto, C. 1983. Behavioural and physiological adaptations to a variable habitat in two species
of case-making caddis larvae using different food. Oikos 41:188–194.
Rubbo, M.J., and Kiesecker, J.M. 2004. Leaf-litter composition and community structure
translating regional species changes into local dynamics. Ecology 85(9):2519–2525.
Rubbo, M.J., J.J. Cole, and J.M. Kiesecker. 2006. Terrestrial subsidies of organic carbon
support net ecosystem production in temporary forest ponds: Evidence from an ecosystem
experiment. Ecosystems 9:1170–1176.
Stearns, S. 1992. The Evolution of Life Histories. Oxford University Press, New York,
NY. 249 pp.
Voss, E.G. 1996. Michigan Flora. Part III. Cranbrook Institute of Science Bulletin 61.
Regeants of the University of Michigan, Ann Arbor, MI. 622 pp.
Wiggins, G.B. 1973. A contribution to the biology of caddisflies (Trichoptera) in temporary
pools. Life Sciences Contribution Royal Ontario Museum 88:1–28.
Wiggins, G.B. 1996. Larvae of the North American Caddisfly Genera (Tricoptera), 2nd
Edition. University of Toronto Press, Toronto, ON, Canada. xiii + 457 pp.
Wiggins, G.B. 2002. Caddisflies: The Underwater Architects. University of Toronto
Press, Toronto, ON, Canada. 292 pp.
Wissinger, S.A., J. Steinmetz, J.S. Alexander, and W.S. Brown. 2004. Larval cannibalism,
time constraints, and adult fitness in caddisflies that inhabit temporary wetlands.
Oecologia 138:39–47.