Areas of Expertise: Crop pollination, African honey bee behavior and population dynamics, and mathematical modeling.
Dr. DeGrandi-Hoffman is a recognized expert in mathematical modeling of honey bee populations. She has constructed the first fruit set prediction models for apples and almonds. She also has uncovered cross-pollination mechanisms for crops such as sunflowers, apples and almond. Dr. DeGrandi-Hoffman also has spent the last 6 years studying the behavior of Africanized honey bees to identify traits that have enabled African bees to displace resident European populations in almost every habitat they have invaded. These include studies uncovering interactions between workers and queens during queen replacement in Africanized honey bee colonies, sperm utilization by queens mated with African and European drones, and fluctuating asymmetries in workers that are hybrids from crosses between African and European bees. Dr. DeGrandi-Hoffman also has conducted experiments to determine the inheritance of defensive behavior in crosses between Africanized and European honey bees. She co-authored the chapter on Africanized honey bees in the upcoming Entomological Society of America Annual Review of Entomology.
Current Research Program: Maintaining European colonies in Africanized habitats is difficult. European colonies become Africanized if the queen open mates. Africanized colonies often reject introduced European queens. European colonies also can be usurped by small swarms of African bees. The emphasis of my research program is to identify factors leading to the rejection of European queens by Africanized colonies and develop methods for requeening Africanized colonies with European queens. I also am determining the factors leading to the usurpation of European honey bee colonies by African bees including the effects of nest usurpation on worker-queen interactionsand characterization of pheromone profiles of invading bees.