The wheat stem sawfly, Cephus cinctus, is a major pest of wheat crops in the Northern Plains of North America; it is responsible for significant loss of crop yield. We are building ecological models to explore ways to control this pest, including biocontrol (augmenting parasitism of the wheat stem sawfly) and the use of resistant wheat cultivars. This project is in collaboration with Dr. Tatyana A. Rand, of the USDA Agricultural Research Laboratory in Sidney, MT

Mnemiopsis leidyi is a ctenophore (comb jelly) with significant summer abundances in coastal waters. They compete with jellyfish and other predators for zooplankton prey, and can have sizable impacts on marine food webs as a result of these interactions. We have studied the timing of gamete release in these simultaneous hermaphrodites, to explore the hypothesis that asynchronous release of sperm and eggs reduces rates of self-fertilization.

Photo credit: Robert Aguilar, SERC (www.marylandbiodiversity.com/viewSpecies. php?species=8601)

Polymictic lakes and reservoirs are bodies of water in which the entire water column is well-mixed multiple times a year. Any stratification that forms is broken up by these mixing events. We are studying the environmental conditions, phytoplankton and zooplankton abundances and community structures in four reservoirs, to explore how these variables change with time (day, season, year) and location (within a reservoir, and among interconnected reservoirs linked in series). This project is a collaboration with Drs. Nathan Ruhl and Michael Grove.

Phytoplankton and zooplankton play critical roles in marine food webs. They mediate bottom-up effects such as nutrient inputs, and top-down effects from a variety of predators. Changes in their abundances, distributions, and species diversity induced by both biotic and abiotic conditions can impact ecosystem dynamics, alter productivity, and affect the resistance and resilience of ecosystems in response to environmental change.  We have studied several questions along these lines using both empirical and theoretical approaches.

Photo credit: Scripps Institute of Oceanography  

(https://scripps.ucsd.edu/zooplanktonguide/species/ acartia-acanthacartia-tonsa)