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.
- Meghan Curry is studying the function of bacterial symbionts in Linyphiid spiders, important natural predators in agroecosystems
- Allison Dehnel, our new laboratory technician, has been helping with everyone’s projects, and is becoming a molecular guru!
- Josh McCord is investigating the interactions between ladybeetles and toxic aphids
- Abi Saeed is exploring symbiont diversity and function in native pollinators
- Steve Wagner is examining whether different symbionts influence host plant use in Aphis craccivora
- Jason Wulff is investigating the defensive properties of Arsenophonus, a bacterial symbiont of the soybean aphid, against Hymenopteran parasitoids
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 email@example.com 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.
- Cristina Brady completed her MS in Dec 2012, and is now 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
- Brady, C.M., and J.A. White. 2013. Cowpea aphid (Aphis craccivora) associated with different host plants has different facultative endosymbionts. Ecological Entomology. Online early DOI: 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., E.C. Burkness, W. D. Hutchison. 2012. Biased sex ratios, mating frequency and Nosema prevalence in European corn borer, at low densities. Journal of Applied Entomology. Online early: DOI: 10.1111/j.1439-0418.2012.01738.x
- 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.
- Chiel E., M. Inbar, N. Mozes-Daube, J. A. White, M. S. Hunter and E. Zchori-Fein. 2009. Assessments of fitness effects by the facultative symbiont, Rickettsia, in the sweetpotato whitefly (Hemiptera: Aleyrodidae). Annals of the Entomological Society of America 102: 413-418.
- 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., J. P. Harmon, and D. A. Andow. 2004. Ecological context for examining the effects of transgenic crops in production systems. Journal of Crop Production 12: 457-489. Special volume: New Dimensions in Agroecology.
- Harmon, J. P., J. A. White, and D. A. Andow. 2003. Oviposition behavior of Ostrinia nubilalis (Lepidoptera: Crambidae) in response to potential intra- and interspecific interactions. Environmental Entomology 32: 334-339.
- 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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