DISSERTATION RESEARCH: Molecular characterization of photoperiod effects on social ontogeny in a bumble bee

University Of Missouri-Saint Louis, Saint Louis MO

Investigators

Abstract

Photoperiod, defined as the cyclical change of sunlight, is one of the most reliable external signals that individuals can perceive to predict environmental changes. Bumble bees maintain a tight association of their life cycle (e.g., colony growth and development; behavior) with seasonal changes in light. The main hypothesis of this project is that photoperiod is a cue that a bumble bee colony uses to shift through consecutive steps during its life cycle. This hypothesis will be evaluated from three different perspectives using the North American native bumble bee Bombus impatiens. First, this study will determine the effects of photoperiod on colony development through manipulations of the Light/Dark cycle. Second, the effect of photoperiod on individual behavior will be quantified using video recording analysis. Third, the study will characterize differences in the molecular components of the circadian clock using gene expression and clock protein localization in the bumble bee brain. It is expected that treatments with increasing day length will produce larger colonies and a synchronized production of new males and queens. At the molecular level is it predicted that changes in photoperiod will correlate with changes in clock gene expression profiles and will affect the localization of clock proteins in the brain. This project will integrate behavioral research and molecular analysis to yield a basic but complete overview of the effects of photoperiod on the social organization and life cycle of B. impatiens. Bumblebees are important pollinators of crops and other plants. In recent decades there has been a worldwide reduction in the populations of bumble bees, and of pollinators in general. Few studies have addressed how photoperiod can affect pollinators and their movements into new environments due to climate change. The investigator is actively involved in outreach activities and this project will involve training of a graduate student, mentorship of undergraduates and public seminars.