Project title

How do climatic conditions and floral resource availability impact bee social behavior and chemical communication?

Mentor's name(s)

Mentor: William Wcislo, STRI staff scientist, WcisloW@si.edu
Co-mentor: Callum Kingwell, STRI postdoctoral fellow, ck0938@princeton.edu
Please cc Paola Galgani galganip@si.edu on any emails regarding this internship.

Location of internship. Will mentor be at this location?

Barro Colorado Island. The mentor(s) will be at this location.

Time of internship

The internship would take place during the dry season of 2025, starting in January or February; the exact starting date for the internship is flexible.

Project summary

The term ‘phenotypic plasticity’ refers to the ability of living things to develop and express a range of possible phenotypes depending on environmental conditions. This flexibility helps to maximize the fitness that an organism’s particular suite of morphological, physiological, and behavioral characteristics (i.e., its phenotype) is likely to yield in a specific environmental context.

This project will focus on species of crepuscular bees in the genus Megalopta that exhibit plastic expression of social behavior. While the most famous bee species live in social groups, most bee species (~90%) are in fact solitary. Megalopta bees can do both: some individuals establish solitary nests, while others establish social colonies with defined queen and worker castes. Foundresses that adopt the social nesting strategy exhibit characteristics that help them in their eventual role as queens; these include the heightened emission of ‘queen pheromone’ compounds, which require valuable nutrients – essential amino acids – for their biosynthesis.

What factors influence whether a bee adopts a solitary or social nesting strategy? While the answer is still unclear, it is likely that individual characteristics, such as body size and genetic background, interact with environmental factors to determine phenotypic expression. Long-term monitoring of Megalopta on BCI indicates that the frequency of social nesting behavior fluctuates with climatic cycles (e.g., El Niño) that are linked to floral availability. Additionally, individuals’ foraging success early in nest establishment is predictive of the social strategy they adopt. Taken together and put simply, these observations suggest that bees may be more likely to be solitary when resources are limited, and more likely to be social when they are abundant. Understanding how bees respond to fluctuating environmental conditions, for example through changes in social behavior, is relevant for predicting how tropical pollinator populations may be impacted by broad environmental changes.

Interns working on this project will work closely with mentors to carry out a field experiment designed to test the hypotheses that floral nutrient intake (a) influences phenotypic plasticity in social behavior and (b) constrains queens’ ability to emit queen pheromone. This will require the establishment and close monitoring of Megalopta observation colonies on BCI, and careful manipulation of nutrient intake of bees using a predefined protocol. Interns will collect data on bee foraging behavior using in-nest cameras, monitor nest development by marking and tracking individual bees, and measure hormone levels, tissue nutrient content, and pheromone production at standardized developmental timepoints.

Mentorship goals

The intern will be expected to work closely with mentors, who will be physically present at the research site, to gain experience with all aspects inherent to the completion of a successful scientific research project. This will include some planning and method development (especially with regard to artificial diet composition and delivery method), hands on experience with wild bees (including nest maintenance and marking techniques), and technical aspects related to data collection. To this last point, the intern can expect to learn how to build and work with a custom-made filming setup employing ‘Raspberry Pi’ cameras and computers, and to learn key methods in chemical ecology including solvent extraction of pheromones, solid-phase microextraction (SPME), and gas-chromatography with flame ionization detection (GC-FID) and/or mass spectrometry (GC-MS).

Intern’s role and expected product

The intern would be expected to be present on Barro Colorado Island for the duration of the study, working closely with other researchers from the Evolution, Behavior, and Neurobiology lab who will be studying Megalopta bees at the site. Megalopta bees are crepuscular, so their biology does not make them amenable to study only during regular working hours (9am-5pm). The actual time commitment will vary in accordance with project demands and seasonal variation in bee activity levels, but hours are generally flexible and interns will also be encouraged to pursue opportunities for professional development at other STRI facilities outside of BCI (see below). The intern is expected to be involved in all aspects of the research project, including field work in the tropical dry forest of BCI, lab work in the BCI facilities, and eventual data analysis and manuscript preparation.

What are the regularly held occasions for group discussions, attendance at lectures, career counseling, and other educational and experiential opportunities for your interns?

The intern will be encouraged to participate in regularly scheduled academic events such as the ‘Behavior Discussion Group’ meetings and ‘BAMBI Seminar’ events to broaden their perspective of ongoing research at STRI and to develop their scientific professional network.

Desired background

We welcome applicants with an academic background and intellectual interest in animal behavior, entomology, and/or chemical ecology. English language proficiency is not required; we can work in English or Spanish as-needed.

Suggested background readings

• Kapheim, K. M., Smith, A. R., Nonacs, P., Wcislo, W. T., & Wayne, R. K. (2013). Foundress polyphenism and the origins of eusociality in a facultatively eusocial sweat bee, Megalopta genalis (Halictidae). Behavioral Ecology and Sociobiology, 67, 331-340.
• Kapheim, K. M. (2017). Nutritional, endocrine, and social influences on reproductive physiology at the origins of social behavior. Current Opinion in Insect Science, 22, 62-70.
• Kingwell, C., Böröczky, K., Steitz, I., Ayasse, M., & Wcislo, W. (2021). Cuticular and dufour’s gland chemistry reflect reproductive and social state in the facultatively eusocial sweat bee Megalopta genalis (Hymenoptera: Halictidae). Journal of Chemical Ecology, 47(4), 420-432.
• Smith, A. (2021). Megalopta. Encyclopedia of Social Insects, 584-587.