We examined the bee diversity in Washington County, Ohio and the pollination services contributed by each species as denoted by the pollen found on the scopa. Lack of information about bee populations makes it difficult to notice change in populations. Furthermore, not many studies have examined the pollen collected by each individual bee. We collected bees at three sites in Washington County to get a representation of the diversity present. Bees were collected every two weeks from April 2013 to October 2013 using pan traps as well as occasional supplemental vane traps and sweepnetting. A total of 2,756 bees were pinned and identified to genus, and if possible, species. Over 33 genera of bees were collected representing over 80 species in five families. The most common genera were Andrena, Osmia, Lasioglossum, and Ceratina. Over 80 bees, predominately Andrena spp., had visible pollen loads; the pollen was identified to family. Floral constancy was determined by evaluating the different types of pollen collected on each individual. Andrena spp. were found to be more constant at the first sample date of April 21st when Claytonia virginica is present. On later dates Andrena was much less constant, with several different types of pollen found on the individuals. We provide a baseline understanding of our current bee populations in SE Ohio as well as insight into the pollination services of each bee species. This data contributes to nationwide research about the current status of bee populations and pollination systems.
Dept of Biology and Environmental Science, Marietta College, Marietta, OH
70 • Angela K. Burrow, Mehul Desai, James E. Russell
Reproduction and Optimal Foraging in the Parasitoid Wasp Trichogramma kaykai
For some animals optimal foraging and reproduction are linked. A classic example of this linkage is found in parasitic wasps that complete development inside host organisms. We studied one such wasp Trichogramma kaykai, an egg parasitoid of the Mormon Metalmark butterfly, Apodemia mormo. For T. kaykai the foraging and reproductive environment primarily consists of patches of individual host eggs. Female foundress wasps measure host eggs, choose how many eggs to oviposit, and then continue foraging for additional hosts. Optimal foraging predicts that a foundress will maximize host utilization per unit time. The resulting F1 generation per host may have variable fitness contingent on brood size thus influencing ovipositing behavior. Field-collected parasitized A. mormo eggs showed variation for T. kaykai brood size, suggesting alternative reproductive/foraging strategies. Two brood size (n=4,5) groups of thirty broods each were collected from the Mojave Desert. A. mormo host eggs were measured for size variation. Broods were supplied with nourishment and host eggs (Ephestia kuehniella) for two days. The F2 generation was assessed for total wasps emerged, females emerged, pupal stage wasps, and proportional fitness. We found no fitness differences between alternative reproductive strategies and no indication of host egg size-proportional fitness covariance. This suggests that individual offspring/brood fecundity for the two brood size groups examined is not influencing foundress oviposition behavior, however, in the highly variable natural environment other selective pressures may impact actual brood fitness. Further research is needed to determine additional factors influencing T. kaykai reproductive optimal foraging decisions.
71 • Brittany D. Harry1, Flor Acevedo2, Michelle Peiffer2, Shan Jin2, Ketia Shumaker, Dr.1, Dawn S. Luthe, Dr.2, Gary Felton, Dr.2
Corn Earworm Saliva Induces Herbivore Defense Gene Expression in Corn
Corn is one of the most important crops worldwide. Corn earworm (Helicoverpa zea) herbivory on corn is costly in terms of the lack of crop yield that occurs and the damage it does. Caterpillar saliva is known to elicit plant defense response in several plants, but surprisingly the effect of H. zea saliva on corn defenses has not been reported. A series of experiments were conducted to determine the expression of several defense-related genes in Z. mays corn plant hybrid MC 4050 after herbivory by H. zea. We tested the saliva of the H. zea to determine if this factor is an elicitor of Z. mays defense gene expression in corn. Corn plants in the V3 stage were challenged with ablated (cauterized spinnerets) and non-ablated (intact spinnerets) H. zea caterpillars for 24 hours. Control plants were not exposed to H. zea caterpillars. The expression of plant defense genes (MPI, LOX3, RIP2) were analyzed by quantitative real-time PCR (qRT-PCR), using Actin as the endogenous control. We found significant differences (α=0.05) among treatments. The greatest gene expression was observed with non-ablated (intact) caterpillars. These results suggest that H. zea saliva is triggering defenses in corn. This information is important because corn is an important food crop worldwide and understanding the components of H. zea saliva that triggers corn defenses against this herbivore will help scientists develop novel insect control strategies. Future experiments will be aimed at identifying the components of H. zea saliva that induces defense gene expression in corn.
