E.W. (Ted) Evans

Lab:                   BNR 234
Lab Phone:        797-0055


RESEARCH

Insect population and community ecology

Ecological basis of biological control

Ecology of invasions

My research is focused at the interface of population and community ecology of insects; I study both insect-insect and insect-plant interactions. The guiding theme of my present efforts is to explore the ecological bases and opportunities for enhancement of biological control of insect pests and weeds.

One major line of my research has been to study the community ecology of biological control of insect pests in Utah’s agricultural fields. In collaboration with students and visiting colleagues, I investigate both direct and indirect interactions among the pests and their natural enemies. The overarching goal has been to evaluate the degree to which the population dynamics of insect pests are interlinked through the foraging activities of natural enemies. Major topics have included the effects of predator diversity on prey suppression; the effects of alternative prey and other naturally occurring foods on target prey suppression; intraguild predation and other effects of invasive species on resident natural enemies and their prey; and efforts to enhance predator effectiveness (conservation biological control). Much of the work on predators has focused on lady beetles (Coccinellidae).

Current and recent graduate student projects associated with this research have included studies of foraging and diet, dispersal and aggregation, and reproduction of parasitoids as well as predators. Other graduate student projects have included population studies of invasive weeds and associated insects introduced as biological control agents, and field studies of pollination biology of grassland and alpine plants. Representative publications from the lab’s research efforts are listed below.

REPRESENTATIVE PUBLICATIONS

Rieder, J.P., T.A.S. Newbold, S. Sato, H. Yasuda, and E.W. Evans. 2008. Intra-guild predation and variation in egg defence between sympatric and allopatric populations of two species of ladybird beetles.Ecological Entomology 33: 53-58.

Evans, E.W. and T.R. Toler. 2007. Aggregation of polyphagous predators in response to multiple prey: ladybirds (Coleoptera: Coccinellidae) foraging in alfalfa.Population Ecology 49: 29-36.

Snyder, W.E., and E.W. Evans. 2006. Ecological effects of invasive arthropod generalist predators.Annual Review of Ecology, Evolution, and Systematics 37: 95-122.

Evans, E.W., J.B. Karren, and C.E. Israelsen . 2006. Interactions over time between cereal leaf beetle (Coleoptera: Chrysomelidae) and larval parasitoid Tetrastichus julis (Hymenoptera: Eulophidae) in Utah.Journal of Economic Entomology 99: 1967-1973.

Kajita, Y., F. Takano, H. Yasuda, and E.W. Evans. 2006. Interactions between introduced and native predatory ladybirds (Coleoptera, Coccinellidae): factors influencing the success of species introductions.Ecological Entomology 31: 58-67.

Evans, E.W. and D.I. Gunther. 2005. The link between food and reproduction in aphidophagous predators: a case study with Harmonia axyridis (Coleoptera: Coccinellidae). European Journal of Entomology 102: 423-430.

Sato, S., H. Yasuda, and E.W. Evans. 2005. Dropping behaviour of larvae of aphidophagous ladybirds and its effects on incidence of intraguild predation. Ecological Entomology 30: 220-224.

Evans, E.W.2004. Habitat displacement of native North American ladybirds by an introduced species. Ecology 85: 637-647.

Jacob, H.S. and E.W. Evans. 2004. The influence of different sugars on the longevity of Bathyplectes curculionis (Hymenoptera: Ichneumonidae). Journal of Applied Entomology 128: 316-320.

Evans, E.W., D.R. Richards, and A. Kalaskar.2004. Using foods for different purposes: female responses to prey in the predator Coccinella septempunctata L. (Coleoptera: Coccinellidae) . Ecological Entomology 29: 27-34.

Yasuda, H., E.W. Evans, Y. Kajita, K. Urakawa, and T. Takizawa. 2004. Asymmetric larval interactions between introduced and indigenous ladybirds in North America. Oecologia 141: 722-731.

Evans, E.W.2003. Searching and reproductive behaviour of female aphidophagous ladybirds (Coleoptera: Coccinellidae): a review. . European Journal of Entomology 100: 1-10.

Jacob, H.S. and E.W. Evans. 2001. The influence of food deprivation on foraging decisions of the parasitoid Bathyplectes curculionis (Hymenoptera: Ichneumonidae). Annals of the Entomological Society of America 94: 605-611.

Rieder, J.P., E.W. Evans, and S.L. Durham. 2001. Distribution of insect attacks in the biological control of weeds: infestation of Centaurea virgata flowerheads by a gall fly. Biological Control 20: 254-260.

Evans, E.W.2000. Morphology of invasion: body size patterns asscoicated with establishment of Coccinella septempunctata in western North America. European Journal of Entomology 97: 469-474.

van der Werf, W., E.W. Evans, and J. Powell. 2000. Measuring and modeling dispersal of Coccinella septempunctata in alfalfa fields. European Journal of Entomology 97: 487-493.

Evans, E.W., A.T. Stevenson, and D.R. Richards. 1999. Essential versus alternative foods of insect predators: benefits of a mixed diet. Oecologia 121: 107-112.

Jacob, H.S. and E.W. Evans . 1998. Effects of sugar spray and aphid honeydew on field populations of the parasitoid Bathyplectes curculionis. Environmental Entomology 27:1563-1568.

Evans, E.W. and D.R. Richards.1997. Managing the dispersal of ladybird beetles (Coleoptera: Coccinellidae): use of artificial honeydew to manipulate spatial distributions. Entomophaga 42:93-102.

Evans, E.W. and S. England.1996. Indirect interactions in biological control of insects: pests and natural enemies of alfalfa. Ecological Applications 6: 920-930.

Evans, E.W.1995. Interactions among grasshoppers (Orthoptera: Acrididae) in intermountain grassland of western North America. Oikos 73:73-78.