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Trichoptera: Phryganeidae of Gunnison County, Colorado

Agrypnia deflata
Giant Case Maker Caddisflies

(Milne 1931)
Updated 20 Apr 2020
TSN 188492
This is an Agrypnia deflata larvae or pupae partially buried in the bottom sediment.
The aquatic plants nearby are a quillwort, Isoetes bolanderi that larvae use to build their spiral cases.
A. deflata larvae easily use other materials to construct their cases,
but prefer Isoetes when it is available.

Good Links

Other Websites:
Photos, Map, Museum specimens, DNA - Barcodinglife.org

University of Alberta Entomology Collection Species page
     Has illustration of male genitalia, description, habitat information, range and more.

Caddisfly Agrypnia deflata pupal_case, usually buried in the sediment

Agrypnia pupal case from a permanent subalpine pond in the Elk Mountains of Colorado August, 2011.
After a year of development in the pond,
A. deflata larvae burrow into the sediment barely enough to cover their case while they pupate :-)
The empty pupal case was netted out of the muck in the bottom of a permanent pond.


Curtis,J 1835 British Entomology being Illustrations and Descriptions of the Genera of Insects found in Great Britain and Ireland Containing Coloured Figure from Nature of the Most Rare and Beautiful Species, and in Many Instances of the Plants Upon Which They are Found. Richard Taylor, London. vol. XII, 530-577.
     Curtis describes the genus Agrypnia in this paper.

Ferry,EE; Hopkins,GR; Stokes,AN; Mohammadi,S; Brodie Jr,ED and Gall,BG 2013 Do all portable cases constructed by caddisfly larvae function in defense?. Journal of Insect Science, 13(1), p.5. html
     Abstract: " The portable cases constructed by caddisfly larvae have been assumed to act as a mechanical defense against predatory attacks. However, previous studies have compared the survival of caddisflies with different cases, thereby precluding an analysis of the survival benefits of "weaker" case materials. The level of protection offered by caddisfly cases constructed with rock, stick, or leaf material, as well as a no-case control, was investigated against predatory dragonfly nymphs (Anax junius Drury (Anisoptera: Aeshnidae)). A valid supposition is that the cases made of stronger material are more effective at deterring predators. Yet, observations revealed that there was no difference in survival between the case types. All caddisflies with a case experienced high survival in comparison to caddisflies removed from their case. In addition, larvae with stick-cases experienced fewer attacks and captures by dragonflies. These results showed that the presence of a case, regardless of the material used in its construction, offers survival benefits when faced with predatory dragonfly nymphs."

Herrmann,SJ 1990 New record and range extension for Rhyacophila wallowa (Trichoptera: Rhyacophilidae) from Rocky Mountain National Park, Colorado. Entomological news (USA).
     While studying R. wallowa, the author found A deflata adults near the cold streams Fall River and Chiquita Creek at 2640m or 8660ft amsl in Rocky Mountain National Park in Colorado.

Jannot,JE; Bruneau,E and Wissinger,SA 2007 Effects of larval energetic resources on life history and adult allocation patterns in a caddisfly (Trichoptera: Phryganeidae). Ecological Entomology, 32(4), 376-383.
     Abstract: " 1. How populations respond to environmental change depends, in part, on the connection between environmental variance during early life stages and its effect on subsequent life-history traits. For example, environmental variation during the larval stage can influence the life histories of organisms with complex life cycles by altering the amount of time spent in each stage of the life cycle as well as by altering allocation to life-history traits during metamorphosis.
2. The effects of larval energetic resources on developmental timing, adult mass, fecundity, mating success, and allocation to adult body structures (thorax, abdomen, wings) were examined in an aquatic caddisfly (Agrypnia deflata Milne, Trichoptera: Phryganeidae). Larval energetic reserves were manipulated by removing larval cases just prior to pupation. In the first experiment, cases of all individuals were removed just prior to pupation; experimental individuals were required to build a new case whereas control individuals were allowed to re-enter their case without building. In the second experiment, energy differences were maximised between the two treatments by supplementing the larval diet of the control group and removing cases and not supplementing the diet of the experimental group.
3. Male and female development time, adult mass, and female fecundity were not influenced by case removal or diet supplementation. In contrast, allocation to adult body parts indicated a trade-off between abdominal and thoracic mass among case-removal females, suggesting that, under larval resource stress, females adjust resource allocation during metamorphosis to alleviate potential negative impacts on clutch size. In addition, latency to copulation increased when cases were removed, indicating larval resource stress could influence male mating success.
4. This study suggests that, under larval energetic stress, the negative impacts on female reproduction might be mitigated by re-allocating resources during metamorphosis, whereas male allocation strategies might not be as flexible as female strategies."

McCullagh,BS; Wissinger,SA and Marcus,JM 2015 Identifying PCR primers to facilitate molecular phylogenetics in Caddisflies (Trichoptera). Zoological Systematics, 40(4) 459 PDF

Milne, L. J. 1931. Three new Canadian Prophryganea (Phryganeidae, Trichoptera). Canadian Entomologist 63
     Original description as Prophryganea deflata

Wiggins,GB 1998 The Caddisfly family Phryganeidae (Trichoptera). University of Toronto Press, Toronto Buffalo London.

Wissinger, SA 2004 Population fluctuations in caddisflies inhabiting high-elevation wetlands in central Colorado . Presented at the NABS Annual meeting, Vancouver, British Columbia, in Population Ecology 2 Abstract

First or second instar of an Agrypnia deflata larvae

This is a first or second instar larval case built from Isoetes fragments, pine needles and a spruce bud scale.
The spiral shape of the case is in preliminary stages.
The larvae is hidden from view.
Note the adult Dipteran built into its case.

Wissinger,SA; Brown,WS and Jannot,JE 2003 Caddisfly life histories along permanence gradients in high altitude wetlands in Colorado (U.S.A.). Freshwater Biology 48(2). PDF
     "SUMMARY 1. Larvae of cased caddisflies (Limnephilidae and Phryganeidae) are among the most abundant and conspicuous invertebrates in northern wetlands. Although species replacements are often observed along permanence gradients, the underlying causal mechanisms are poorly understood. In this paper, we report on the distributional patterns of caddisflies in permanent and temporary high-altitude ponds, and how those patterns reflect differences in life history characteristics that affect desiccation tolerance (fundamental niches) versus constraints related to biotic interactions (realised niches).
2. Species (Hesperophylax occidentalis and Agrypnia deflata) that were encountered only in permanent ponds are restricted in distribution by life history (no ovarian diapause, aquatic oviposition, and/or inability to tolerate desiccation). Although the egg masses of H. occidentalis tolerate desiccation, the larvae leave the protective gelatinous matrix of the egg mass because adults oviposit in water.
3. Three species (Asynarchus nigriculus, Limnephilus externus and L. picturatus) have life history characteristics (rapid larval growth, ovarian diapause and terrestrial oviposition of desiccation-tolerant eggs) that should facilitate the use of both permanent and temporary habitats. However, A. nigriculus is rare or absent in most permanent ponds, and L. externus and L. picturatus are rare or absent in most temporary ponds. Experimental data from a previous study on the combined effects of salamander predation and interspecific interactions among caddisflies (e.g. intraguild predation) suggest that biotic interactions limit each species to a subset of potentially exploitable habitats.
4. Many wetland invertebrates exhibit species replacements along permanence gradients, but few studies have separated the relative importance of the effects of drying per se from the effects of biotic interactions. Our results emphasise the complementary roles of comparative data on life histories and experimental data on competition and predation for understanding invertebrate distributions along permanence gradients."

Wissinger,SA; Eldermire,C and Whissel,JC 2005 The role of larval cases in reducing aggression and cannibalism among caddisflies in temporary wetlands. Wetlands 24(4) 777-783. PDF
     Abstract: " Larvae of wetland caddisflies supplement their detrital diets with animal material. In some species this supplement is obtained by preying on other caddisflies. In this study, we conducted a series of laboratory experiments to a) compare intraspecific aggression and the propensity for cannibalism among six caddisfly species that occur along a gradient from vernal to autumnal to permanent high-elevation wetlands, and b) determine the importance of cases in preventing or reducing cannibalism and intraguild predation. We predicted that cannibalism and overall levels of aggression should be highest in species that occur in temporary habitats. We found that all of the species that use temporary habitats (Asynarchus nigriculus ,Hesperophylax occidentalis, Limnephilus externus, Limnephilus picturatus, Limnephilus secludens) were extremely aggressive towards and cannibalized conspecifics without cases. Species that typically occur in short-duration temporary wetlands were more aggressive than those in long-duration temporary wetlands. Cases prevented cannibalism in four of these temporary-habitat species, and reduced cannibalism among Asynarchus larvae. The latter species occurs in extremely ephemeral habitats where cannibalism provides a dietary supplement that probably facilitates emergence before drying. Asynarchus also preys on Limnephilus spp., and we found that cases dramatically reduced vulnerability to intraguild predation. Larvae of Agrypnia deflata, a species that occurs only in permanent wetlands, were least aggressive and rarely cannibalized conspecifics. Our results are consistent with the hypothesis that intraspecific aggression and the potential for cannibalism are highest in species that live in habitats with developmental time constraints. Many wetland invertebrates face developmental time constraints and selection for aggression in temporary habitats should be especially strong for taxa that rely on animal material to supplement a mainly detrital diet."

Wissinger,SA; Whissel,J; Eldermire,C and Brown,W 2006 Predator defense along a permanence gradient: roles of case structure, behavior, and developmental phenology in caddisflies, Oecologia, Pages 1 - 12. Pdf Icon (311 KB)
     Abstract: "Species replacements along freshwater permanence gradients are well documented, but underlying mechanisms are poorly understood for most taxa. In subalpine wetlands in Colorado, the relative abundance of caddisfly larvae shifts from temporary to permanent basins. Predators on caddisflies also shift along this gradient; salamanders (Ambystoma tigrinum nebulosum) in permanent ponds are replaced by predaceous diving beetles (Dytiscus dauricus) in temporary habitats. We conducted laboratory and field experiments to determine the effectiveness of caddisfly cases in reducing vulnerability to these predators. We found that larvae of a temporary-habitat caddisfly (Asynarchus nigriculus) were the most vulnerable to salamanders. Two relatively invulnerable species (Limnephilus externus, L. picturatus) exhibited behaviors that reduced the likelihood of detection and attack, whereas the least vulnerable species (Agrypnia deflata) was frequently detected and attacked, but rarely captured because cases provided an effective refuge. Vulnerability to beetle predation was also affected by cases. The stout cases of L. externus larvae frequently deterred beetle larvae, whereas the tubular cases of the other species were relatively ineffective. Two of these vulnerable species (A. nigriculus and L. picturatus) often co-occur with beetles; thus, case construction alone is insufficient to explain patterns of caddisfly coexistence along the permanence gradient. One explanation for the coexistence of these two species with beetles is that they develop rapidly during early summer and pupate before beetle larvae become abundant. One species (L. picturatus) pupates by burying into soft substrates that serve as a refuge. The other (A. nigriculus) builds stone pupal cases, which in field experiments, more than doubles survival compared to organic pupal cases. The combined results of these experiments suggest that caddisfly distributions along permanence gradients depend on a suite of primary and secondary predator defenses that include larval and pupal case structure, predator-specific escape behaviors, and the phenology of larval development."

Brown,WS 2005 Trichoptera of Gunnison County, Colorado, USA