The focus of my laboratory is investigating the ecological, evolutionary, and behavioral effects of bacterial endosymbionts in insects. In particular, we are interested in exploring the consequences of endosymbiont infection within the context of introduced species and biological control.
Maternally-inherited bacterial endosymbionts are common among arthropods. Some symbionts are obligate and mutualistic, providing their hosts with nutrients or performing other essential functions in their hosts. Other symbionts are “facultative”, without which hosts can survive and potentially thrive. In recent years, it has become increasingly evident that these facultative symbionts can have major effects on their host’s biology, including: manipulation of host reproduction, influencing dispersal, affecting host plant choice, changing host temperature tolerances, altering fecundity, and providing defense against parasitoids, fungi, and viruses. These effects, in turn, have the potential to influence the ecological interactions between infected hosts and other members of the community. For example, an aphid that is infected by a symbiont that protects against parasitism may be harder to control biologically, and more likely to reach pest outbreak status, than an uninfected aphid. Yet studies that address these ecological effects of bacterial symbionts in the field are practically nonexistent. The ultimate goal of my research program is to test the importance of bacterial symbionts in driving pest/enemy interactions in the field.
Current lab members are undertaking a number of projects that relate to this topic.
- Paul Lenhart, post-doctoral scholar, is a community ecologist with expertise in taxonomy, nutritional physiology, and community analysis. In the endosymbiont ecology lab, Paul is elucidating the real-world effects of aphid defensive phenotypes. Different biotypes of the cowpea aphid (Aphis craccivora) have been shown to be toxic to particular natural enemies in laboratory experiments. In some cases defense is mediated by facultative symbionts. Paul's piece of the puzzle is to determine whether these effects extend to the field. Factors that vary within a species, such as symbiont infection status and host plant origin, could be leading to insect outbreaks, which have important economic and ecological consequences. Paul also has an exploratory project investigating orthopteran microbiomes.
- Kelly Jackson, MS student, is investigating the behavior and fitness of ladybird beetles fed toxic versus nontoxic aphid food sources.
- Thor Hansen, MS student, is studying the mechanistic interactions between aphids, their obligate symbiont, and their facultative symbiont, particularly in the context of nutrition and host plant use.
- Alex Styer, scientific technician, is characterizing the dynamics of symbiont infection in natural spider populations.
I also have ongoing interests in host/parasitoid behavior, spatial interactions, and population dynamics (even when symbionts are not involved!)
Aphis craccivora (photo by Cristina Brady)
Information for Prospective Students
Although funding is tight, I am always seeking motivated graduate students. Please contact me at firstname.lastname@example.org if you are interested in learning more about research opportunities in my laboratory.
Right: Encarsia inaron, a biological control agent of the ash whitefly (Siphoninus phillyreae) and the sweet potato whitefly (Bemisia tabaci). Photo: Mike Rose.
- Allison Dehnel, former technician, is seeking employment in Missoula MT. If you are in the area, you should hire her. She's fantastic.
- Yong-Ming Ruan, visiting scholar, is back at his home institution, Zhejiang Normal University, Jinhua, China.
- Jason Wulff, PhD 2014, is a postdoctoral associate at Texas A&M University.
- Josh McCord, BS 2014, is a current MS student in UK Entomology.
- Abi Saeed, MS 2014, is an extension agent at Michigan State University.
- Meghan Curry, MS 2014, has her very own entomophagy start-up, Bugvivant.com.
- Steve Wagner, defended his MS in 2014, and works for Syngenta.
- Cristina Brady, MS 2012, is a Research Specialist in the Department of Cell & Developmental Biology at the University of Pennsylvania.
- Ali Maldonado, former technician, relocated to Trimble Co., KY, where she teaches junior high.
- Cheryl Lindsay Bowker, former technician, is a PhD candidate in Entomology at Colorado State University.
- Susan Romero, former technician, works for the USDA in Arizona, identifying insects intercepted at the border.
- Wagner, S.M., A. J. Martinez, Y. Ruan, K. L. Kim, P. A. Lenhart, A. C. Dehnel, K. M. Oliver, and J. A. White. 2015. Facultative endosymbionts mediate dietary breadth in a polyphagous herbivore. Online early, Functional Ecology 29: 1402-1410. DOI: 10.1111/1365-2435.12459
- Saeed, A., J. A. White. 2015. Surveys for maternally-inherited endosymbionts reveal novel and variable infections within solitary bee species. Journal of Invertebrate Pathology 132: 111-114. DOI: 10.1016/j.jip.2015.09.011
- Curry, M.M., L. V. Paliulis, K. D. Welch, J. D. Harwood, J. A. White. 2015. Multiple endosymbiont infections and interacting reproductive manipulations in a linyphiid spider population. Heredity 115: 146-152. DOI: 10.1038/hdy.2015.2
- Wulff, J. A., and J. A. White. 2015. The endosymbiont Arsenophonus provides a general benefit to soybean aphid (Hemiptera: Aphididae) regardless of host plant resistance (Rag). Environmental Entomology 44: 574-581. DOI: 10.1093/ee/nvv03
- Gebiola, M., J. A. White, B. N. Cass, A. Kozuch, L. R. Harris, S. E. Kelly, J. Karimi, M. Giorgini, S. J. Perlman, M. S. Hunter. 2015. Revisiting a classic biological control success story reveals cryptic host and symbiont diversity. In press, Biological Journal of the Linnean Society. DOI: 10.1111/bij.126
- White, J.A., N. K. Richards, A. Laugraud, A. Saeed, M. M. Curry, and M. R. McNeill. 2015. Endosymbiotic candidates for parasitoid defense in exotic and native New Zealand weevils. Microbial Ecology 70:274-286. DOI: 10.1007/s00248-014-0561-8
- Brady, C.M., M. Asplen, G.E. Heimpel, K.R. Hopper, C. Linnen, K.M. Oliver, J.A. Wulff, and J.A. White. 2014. Worldwide populations of Aphis craccivora have diverse facultative bacterial symbionts. Microbial Ecology 67: 195-204. DOI: 10.1007/s00248-013-0314-0
- White, J.A. 2013. Evolution: a bacterially-mediated swap meet for adaptive traits. Current Biology 23: R723-R725. DOI: 10.1016/j.cub.2013.07.069
- Brady, C.M., and J.A. White. 2013. Cowpea aphid (Aphis craccivora) associated with different host plants has different facultative endosymbionts. Ecological Entomology 38:433-437DOI: 10.1111/een.12020
- Wulff, J.A., K.A. Buckman, K. Wu, G.E. Heimpel, and J.A. White. 2013. The endosymbiont Arsenophonus is widespread in soybean aphid, Aphis glycines, but doesn't provide protection from parasitoids or a fungal pathogen PLOS ONE 8:e62145.
- White, J.A., M. Giorgini, M. Strand, F. Pennacchio 2013. Arthropod endosymbiosis and evolution. Pp. 441-477 in Arthropod Biology and Evolution – Molecules, Development, Morphology. A. Minelli, G. Boxshall and G. Fusco, eds. DOI: 10.1007/978-3-642-36160
- Brady, C.M., and J.A. White. 2012. Late instar parasitism of whitefly hosts by Encarsia inaron has negative consequences for both parasitoid and host. Annals of the Entomological Society of America 105:840-845.
- White, J.A. 2011. Caught in the act: rapid, symbiont-driven evolution. BioEssays 33: 823-829.
- White, J. A., C. Hurak, J. A. Wulff, M. S. Hunter, and S. Kelly. 2011. Parasitoid bacterial symbionts as markers of within-host competitive outcomes: superparasitoid advantage and sex ratio bias. Ecological Entomology 36: 786-789.
- White, J.A., S. E. Kelly, S. N. Cockburn, S. J. Perlman, M. S. Hunter. 2011. Costs and benefits of endosymbiont infection in a doubly-infected parasitoid. Heredity 106: 585-591.
- White, J.A., S. Kelly, S. Perlman, M. S. Hunter. 2009. Cytoplasmic incompatibility in the parasitic wasp Encarsia inaron: disentangling the roles of Cardinium and Wolbachia symbionts. Heredity 102: 483-489.
- White, J. A., and D. A. Andow. 2008. Benefits of self-superparasitism in a polyembryonic parasitoid. Biological Control 46: 133-139.
- White, J. A., and D. A. Andow. 2007. Foraging for intermittently refuged prey: theory and field observations of a parasitoid. Journal of Animal Ecology 76: 1244-1254.
- White, J. A., and D. A. Andow. 2006. Habitat modification contributes to associational resistance between herbivores. Oecologia 148: 482-490.
- White, J. A., and D. A. Andow. 2005. Host-parasitoid interactions in a transgenic landscape: spatial proximity effects of host density. Environmental Entomology 34: 1493-1500.
- White, J. A. and T. G. Whitham. 2000. Associational susceptibility of cottonwood to a box elder herbivore. Ecology 81: 1795-1803.
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