The current 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 intracellular endosymbionts are common among arthropods, with the most widespread bacterial endosymbiont, Wolbachia, recently estimated to infect 66% of arthropod species, albeit often at low prevalence within a species. Host arthropods can survive and potentially thrive without such “facultative” symbionts, and because they usually cannot be cultivated in vitro, their roles within the host remained obscure for many years. With the advent of molecular techniques, however, interest in these bacteria has escalated and it has become increasingly evident that facultative symbionts can have major effects on their host’s biology, ecological relationships, and evolutionary dynamics. For example, various facultative symbionts have been shown to: manipulate host reproduction, influence dispersal, affect host plant choice, change host temperature tolerances, alter fecundity, and provide defense against parasitoids, fungi, and viruses. There is little generality to our current understanding of symbiont effects, however. The same symbiont can cause different phenotypic effects in different host species, we know little of the mechanisms that result in an observed phenotype, and the broader ecological consequences of symbiont infection upon a host species are largely unexplored. Because many described symbiont effects would likely influence the establishment and spread of introduced species, it is clear that the presence or absence of symbionts could have important ramifications for introduced species, including biological control agents.
Current lab members are undertaking a number of projects that relate to this topic.
- Cristina Brady is investigating geographic diversity in worldwide populations of the cowpea aphid, Aphis craccivora, an introduced legume pest
- Meghan Curry is studying the function of bacterial symbionts in Linyphiid spiders, important natural predators in agroecosystems
- Ali Maldonado is spearheading our effort to identify bacterial symbionts in introduced aphids
- Josh McCord is our undergraduate jack of all trades, who's looked at symbiont diversity in weevil biological control agents, and host plant usage by Aphis craccivora
- Abi Saeed is exploring symbiont diversity and function in native pollinators
- Steve Wagner is examining whether different symbionts in Aphis craccivora influence the aphid's interactions with ants
- 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
I am always seeking motivated graduate students, and have funding available for student support. 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.
- 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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