Santa Clara University

Janice Edgerly-Rooks

Professor

Educational Background
B.A., State University of New York, Cortland
M.S., State University of New York, Syracuse
Ph.D., Cornell University

Teaching
I teach courses in entomology, ecology, behavior, and biodiversity at SCU. I also take students to Trinidad and Tobago (T&T) during the summer as part of a course on environmental biology and environmental policy (which I teach with Prof. Dennis Gordon of Political Science). Students have also participated in independent research projects in T&T (see The Santa Clara Magazine cover story in the March 1999 issue) working on environmental issues ranging from ethnobotany, environmental awareness, bird and insect censuses to community organization and history. Peg Graham of Anthropology at SCU assisted me in advising the research students.

Research
I investigate questions about the behavior and ecology of insects. I have studied treehole mosquitoes, embiids (webspinning insects)and tent caterpillars. Presently, my students and I are concentrating our attention on the little known group of insects, the embiids (Order Embiidina or Embioptera). I'm working with colleagues at the University of New Mexico and the University of California Riverside on the evolution of silk spinning in embiids. See our embiid research at www.oligotoma.com

 

Behavior of Webspinners
I studied webspinners for my Ph.D. work at Cornell University and continued to study them off and on over the years. Mostly my work focuses on basic behavior and ecology of these insects. They remain one of the least known of all the insect orders, perhaps because they are mostly tropical and quite secretive. They live under silken covers and within tunnels that they spin with silk produced by glands in their front feet. My research seeks to determine the level of social organization in these colonial insects, and to discover which factors influence their behavior including their use of silk. I also wish to describe their basic behavior in a detailed manner,because until now most reports are anecdotal. Below I list some of the research problems I am investigating with colleagues and my students.

 

Does the silk protein show diversity in embiids?
Silk is spun by insects in three orders: Hymenoptera, Lepidoptera and Emdiidina.

 

Does the silk protein differ between or within these insect ordersand if so are the differences related to function?
My preliminary analysis of protein composition of embiid silk suggests that their silk varies in the proportions of different amino acids, such as phenylalanine. The silk ranges in color as well from bright white to lavender. These observations suggest that embiid silk has diversified. Our task now is to determine how and why.

 

How can embiids live in such diverse locations given undefinedthat their body form is so uniform, one species to the next?
Embiid habitats range from humid tropical rain forests to arid, hot climes. Yet their body form is the same in each place; that is, they are elongate, flexible, and fairly soft-bodied for an insect. Females are always wingless and nymph-like. One might expect morphological diversity given the range of climates, but perhaps dwelling within tight silk tubes has selected for their streamlined form. We have discovered recently that embiids may vary physiologically rather than morphologically. I, with Dr. Elizabeth Dahlhoff of SCU, have begun to investigate heat shock proteins in embiids. Our lab data suggest that embiids from mild climes cannot cope with high temperatures whereas embiids from hot areas are resistant to very high temperatures.

 

Do embiid species vary in their habitat requirements? If so, do their habitats correlate with silk use and structure?
I recently have documented ecological correlates of embiid habitats. I started in Australia where two species co-occur on Magnetic Island, but where they seem to use different microhabitats. A detailed survey suggests that each is a specialist to some degree: a lichen-eater and a leaf litter-dweller that have overlapping ranges with slight differences. One striking difference seems to be heat; one of the species lives in astonishingly hot locales.

 

How do embiids spin silk, how costly is it to spin, and how does its use vary across the order?
Embiids vary in their tendency to spin silk although the motions of spinning are probably very similar. Some spin copious amounts whereas others are reluctant to spin at all when removed from their silken domiciles. The latter seems to rely on substrate materials to construct their homes and use silk as an adhesive. The former creates elaborate silk domiciles using the substrate as foundation only. Questions arise: does their variable reliance on silk relate to their tendency to share silk? Are colonial embiids more likely to need and use more silk, and hence can they benefit from sharing? Is it costly to spin? Recent work in my lab suggests that silk spinning is about half as metabolically costly as locomotion. As yet we have not been able to demonstrate a reproductive consequence of silk spinning for three species tested thus far. Embiid silk is constructed of the simplest of all amino acids, those that are readily available to an animal producing such a protein. Perhaps silk is not costly to produce because the amino acids are so ubiquitous in their food. We are still investigating this question. Because silk dominates the lifestyle of webspinners the question deserves to be asked and hopefully answered.

 

Janice with colleagues Pisit & Praset, collecting embiids in Thailand 2009

 

 

 

 

Publications

Fitzgerald, T. D. and J. S. Edgerly. 1979. Exploration and recruitment in field colonies of eastern tent caterpillars. Journal of the Georgia Entomological Society. 14: 312-314.

Fitzgerald, T. D. and J. S. Edgerly. 1979. Specificity of trail markers of forest and eastern tent caterpillars. Journal of Chemical Ecology. 5: 565-574.

To see more of Edward Rooks paintings please go to www.rooksart.com

Edgerly, J. S. and T. D. Fitzgerald. 1982. An investigation of behavioral variability in colonies of the eastern tent caterpillar, Malacosoma americanum (Lepidoptera: Lasiocampidae). Journal of the Kansas Entomological Society. 55: 145-155.

Fitzgerald, T. D. and J. S. Edgerly. 1982. Site of secretion of the trail marker of the eastern tent caterpillar. Journal of Chemical Ecology. 8: 31-39.

Shaw, S. R. and J. S. Edgerly. 1986. A new braconid genus (Hymenoptera) parasitizing webspinners (Embiidina) in Trinidad. Psyche. 92: 505-511. Edgerly, J.S. 1987. Maternal behavior of a webspinner (Order Embiidina). Ecological Entomology. 12: 1-11.

Edgerly, J. S. 1987. Colony composition and some costs and benefits of facultatively communal behavior in a Trinidadian webspinner (Embiidina: Clothodidae). Annals of the Entomological Society of America. 80: 29-34.

Livdahl, T. P. and J. S. Edgerly. 1987. Hatching inhibition: population regulation in a treehole mosquito. Ecological Entomology. 12: 395-399.

 Edgerly, J. S. 1988. Maternal behaviour of a webspinner (Order Embiidina): mother-nymph associations. Ecological Entomology. 13: 263-272.

Edgerly, J. S. and T. P. Livdahl. 1992. Density-dependent interactions within a complex life cycle: the roles of cohort structure and mode of recruitment. Journal of Animal Ecology. 61: 139-150.

Edgerly, J. S. and Michelle A. Marvier. 1992. To hatch or not to hatch? Egg hatch response to larval density and to larval contact in a treehole mosquito. Ecological Entomology. 17: 28-32.

Edgerly, J. S, M. S. Willey, and T. P. Livdahl. 1993. The community ecology of Aedes egg hatching: implications for a mosquito invasion. Ecological Entomology. 18: 123-128.

Edgerly, J. S. 1994. Is group living an antipredator defense in a facultatively communal webspinner? Journal of Insect Behavior. 7: 135-147.

Edgerly, J. S. 1997. Life Beneath Silk Walls: A Review of the Primitively Social Embiidina. Chapter in The Evolution of Social Behavior in Insects and Arachnids, (Eds. J. Choe and B. Crespi). Cambridge University Press.

Edgerly, J. S., M. McFarland, P. Morgan, T. Livdahl. 1998. A seasonal shift in egg-laying behaviour in response to cues of future competition in a treehole mosquito. Journal of Animal Ecology. 67: 805-818.

Edgerly, J.S., A. Shachter, and W. Calder. 1999. Course-based campus environmental research projects. The Declaration. (a newsletter published by the Association of University Leaders for a Sustainable Future). 3: 10-12.

Edgerly, J.S., M. S. Willey, and T. Lidvahl. 1999. Intraguild predation among larval treehole mosquitoes, Aedes albopictus, Ae. aegypti, and Ae. triseriatus (Diptera: Culicidae), in laboratory microcosms. Journal of Medical Entomology. 36: 394-399.

Shachter, A. M. and J. S. Edgerly. 1999. Campus environmental resource assessment projects for non-science majors. Journal of Chemical Education. 76: 1667-1670

Edgerly, J. S., J. A. Davilla, and N. Schoenfeld. 2002. Silk spinning behavior and domicile construction in webspinners. Journal of Insect Behavior. 15: 219-242.

Edgerly, J.S., E. C. Rooks. 2004 Lichens, Sun, and Fire: A Search for an Embiid-Environment Connection in Australia (Order Embiidina: Australembiidae and Botoligototmidae). Environmental Entomology. vol. 33(4): 907-920.

Edgerly, J.S., Archana Tadimalla, and Elizabeth P. Dahlhoff. 2005. Adaptation to thermal stress in the lichen-eating webspinners (Embioptera): habitat choice, domicile construction and the potential role of heat shock proteins. Functional Ecology. 19:255-262.

Edgerly, J.S., S.M. Shenoy, and V.G. Werner. 2006. Relating the cost of spinning silk to the tendency to share it for three embiids with different lifestyles (Order Embiidina: Clothodidae, Notoligotomidea, and Australembiidae). Environmental Entomology. 35:448-457.

Edgerly, J.S., Claudia Szumik, Chanel N. McCreedy. 2007. On new characters of the eggs of Embioptera with the description of anew species of Saussurembia (Anisembiidae). Systematic Entomology. 32 (2), 387-395.

Kelly B. Miller and J.S. Edgerly. 2008. Systematics and natural history of the Australian genus Metoligotoma Davis (Embioptera: Australembiidae). Invertebrate Systematics. 2:329-344.

Szumik, C., J.S. Edgerly, and C. Hayashi. 2008. Phylogeny of Embiopterans (Insecta). Cladistics. 24: 993-1005.

Collin, M. A., Jessica E. Garb, J S. Edgerly, and Cheryl Y. Hayashi. 2009. Characterization of silk spun by the embiopteran, Antipaluria urichi. Insect Biochemistry and Molecular Biology. 39: 75-82.