Project title
Host-Symbiont Interactions across a Sociality Continuum: Insights from Bees & Nematodes
Mentor's name
William Wcislo, STRI staff scientist
WcisloW@si.edu
Please copy Paola Galgani (galganip@si.edu) on any emails regarding this internship.
Co-mentor’s name
Charlotte Knopp, STRI short-term fellow
ck8037@princeton.edu
Location of internship
Barro Colorado Island
Project summary
Halictid bees (‘sweat bees’) are a species-rich family of bees whose lifestyles range from solitary to eusocial colonies of ~400 workers, providing a powerful system for comparative studies of central concepts in disease ecology such as commensalism, tolerance, virulence, and transmission across different scales of social organization. We aim to understand how social structure impacts where symbionts lie on the mutualist-commensal-parasite continuum by using several halictid species, which can house >4000 non-feeding Acrostichus nematodes in an abdominal exocrine gland. Megalopta genalis and Megalopta amoena are facultatively eusocial bees found on Barro Colorado Island in Panama. Females of these species can initiate either eusocial or solitary nests, allowing us to directly compare how nematodes impact bees with different social phenotypes.
Where Acrostichus nematodes fall across the mutualism-commensalism-parasitism spectrum is unknown. We hypothesize that the nematodes perform mutualistic cell-cleaning behaviors which increase survival of the brood, but that at high burdens they may have a negative (parasitic) impact on adult bees due to the physiological cost of life with nematodes.
To test these hypotheses, we use a combination of observational and molecular techniques. We collect bees in the field, assess their nematode burden, and then take metrics of reproductive capacity, body condition, and immune activation. We also perform behavioral assays with the nematodes to determine if their host-seeking behaviors are influenced by bee social organization (i.e. solitary vs. eusocial) or caste (i.e. queen vs. worker).
Mentorship goals
Interns on this project will learn the essentials of field research and gain knowledge of disease ecology and behavioral ecology while living and working in the diverse research community at STRI. Mentors will discuss the interns’ career goals to ensure they receive training that helps them progress in their scientific careers. Depending on their areas of interest, interns will also gain skills in experimental design, behavioral assays, insect husbandry, and statistical analysis (spreadsheet use, programming in R, etc.). Interns will be co-authors on any scientific publications that result from this study.
This is a relatively new project with many components, so there is room to tailor work to interns’ interests. Students are welcome to bring their own ideas and may conduct a side-project that is complementary to the main aims of this project.
Desired background
Students with interest or experience in any area of evolutionary biology, ecology, or environmental science would be welcome. Particular interest in host-parasite interactions, animal behavior, or immunology is desirable. Interns must be comfortable working under harsh conditions in the field (heat, humidity). This is a full-time internship and will take place on BCI over a 3-month period. Time allocation is approximately 60% fieldwork and 40% lab work.
¡Solicitudes en español son bienvenidas!
Suggested background readings
- Giblin-Davis, R. M., Norden, B. B., Batra, S. W. T., & Eickwort, G. C. (1990). Commensal Nematodes in the Glands, Genitalia, and Brood Cells of Bees (Apoidea). Journal of Nematology, 22(2), 150–161.
- McFrederick, Q., Roulston, T. H., & Taylor, D. (2013). Evolution of conflict and cooperation of nematodes associated with solitary and social sweat bees. Insectes Sociaux, 60(3), 309–317. https://doi.org/10.1007/s00040-013-0295-5
- McFrederick, Q. S., & Taylor, D. R. (2013). Evolutionary history of nematodes associated with sweat bees. Molecular Phylogenetics and Evolution, 66(3), 847–856. https://doi.org/10.1016/j.ympev.2012.11.007
- Wcislo, W. T., Arneson, L., Roesch, K., Gonzalez, V., Smith, A., & Fernández, H. (2004). The evolution of nocturnal behaviour in sweat bees, Megalopta genalis and M. ecuadoria (Hymenoptera: Halictidae): an escape from competitors and enemies? Biological Journal of the Linnean Society, 83(3), 377–387. https://doi.org/10.1111/j.1095-8312.2004.00399.x
