Freshwater mussels (Unionidae) are some of the most highly threatened animals in the United States and around the world. Understanding why these organisms are so sensitive is critical to preventing further species declines. Therefore, I am interested in the factors that regulate the timing of freshwater mussel reproduction, the most sensitive period of most animals' lives. Specifically, I am examining how temperature, photoperiod and food availability interact to influence mussel physiology (energy reserves) and reproductive output. (Photo: collecting gonad samples using a non-lethal syringe biopsy technique)

Because mussels are broadcast spawners and have high rates of dispersal and gene flow, speciation in these organisms has been assumed to be rare. However, freshwater mussel beds often contain numerous closely related species, indicating that speciation might not be as rare as once thought. Understanding the process of speciation in freshwater mussels requires a more thorough knowledge of the mechanisms of reproductive isolation. Therefore, I am interested in the barriers to interspecific fertilization in three closely related species of mussels (Quadrula cylindrica, Q. pustulosa, Q. quadrula). My research focuses on habitat use, timing of reproduction, sperm chemotaxis, and gamete incompatability as mechanisms for "ensuring" conspecific fertilization. (Photo: collecting mussels with Tulah in the Little River)