The honeybee, Apis mellifera, is not only crucial in maintaining biodiversity by pollinating 85% plant species but also is the most economically valuable pollinator of agricultural crops worldwide with value between $15 and $20 billion annually as commercial pollinators in the U.S. Unfortunately, the recent sharp declines in honeybee population have been considered a global crisis. The primary cause of colony losses is the parasitic Varroa mite. Varroa parasitize immature and adult bees.  Stress from parasitism shortens the life of adult workers. The mites also transmit deadly viruses that can reduce brood survival and cause adults that were parasitized during development to have developmental deformities and compromised cognitive function particularly learning and memory. Consequently, infected foragers might be more likely to drift to other colonies which facilitates parasitism and virus infection across a larger spatial scale, especially under nutritional stress. Mathematical models have begun to provide insights on ecological processes and important factors that contribute to the mortality of honeybees. However, the previous models, without validation and parameterization with data, are either detailed simulation models that are mathematically untrackable or over simplified models lacking essential biological components. Mathematically tractable/novel models that have a better alignment with data were needed to unfold the mystery of the dramatic decline in honeybee populations and for developing control strategies for Varroa that reduce colony losses.

Our collaborative research between PIs Kang from Arizona State University and DeGrandi-Hoffman from Carl Hayden Bee Research Center fosters a culture of theory-experiment collaboration that allows us to develop realistic and mathematically tractable models that have been validated and parameterized using field data.  Our collaboration enables us to study the integrated effects of disease, parasitism, nutrition and behavior in changing environments and the effects on honeybee colony mortality across multiscale in time and space using actual field data for model development and validation. We have been using individual-based models, ODEs, DDEs, and SDEs models to address important questions such as 1. How parasite migration into colonies via foragers from other hives located at different landscape structures could affect the honeybee-parasite population dynamics with stage structures. 2. How the honeybee-parasite-virus interactions with the honeybee foraging behavior in seasonal environments cause colony losses. 3. How the crucial feedback mechanisms linking disease, parasitism, nutrient, and honeybee foraging behavior might be responsible for the colony growth dynamics and survival in a dynamical environment with multilevel spatial components. Our collaboration results in more than 32 publications in the high-profile journals of mathematical biology that have been presented in more than 40 research presentations in varied national and international conferences.

Our research lives at the intersection of epidemiology, life sciences and applied mathematics, which enables us to develop a template integrating interdisciplinary learning for students through shared research projects at the undergraduate and/or graduate level. Our framework provides not only a powerful system for examining multifactorial impacts on the honeybee colony system but also a great opportunity to explore how behavior, epidemiology and nutritional ecology coevolve within complex systems in general. Our research provides a basis for new strategies for controlling Varroa and reducing colony losses for beekeepers, and benefit land managers. Our excellent work has been featured in the article titled “ How to hatch, brew and Craft the perfect maths partnership” that was published in Jun 26, 2023 at the prestige  journal of Nature Career Section (https://www.nature.com/articles/d41586-023-02038-1). These achievements demonstrate the reach and impact of our work and highlight the value of cross-cultural partnerships in advancing scientific knowledge. 

Our research projects supported both graduate and undergraduate students from both math and biology programs. The fund partially supported 8 graduate students and 12 undergraduate students. Most of those students are minority. Among those students, we graduated two female PhD in Applied Mathematics, and one PhD in Animal Behavior. We also graduated one master in Applied Mathematics and two honor undergraduates whose theses are in line with this research topic. All students involved in this research had opportunities to present their research findings in the varied national and international meetings (either in person or virtually).  Suitable research projects have been integrated into undergraduate mathematical biology courses that contributes to recent launched Applied Mathematics B.S. Program at ASU. Our methods and results have been disseminated through online video lectures and in-person workshops that can be made available to the scientific community. The funds partially supported minority graduate students. Our team effort has the following impacts on the development of human resources provided opportunities for research and teaching in the field of mathematical biology through involving both undergraduate and graduate students from diverse background; improved the performance, skills, or attitudes of members of underrepresented groups that would improve their access to or retention in research, teaching in the field of mathematical biology; developed and disseminated new educational materials.

Last Modified: 12/02/2023
Modified by: Yun Kang