Research

Disturbance and environmental change can remove flowers or pollinators from a community, and the consequences for the remaining species and their interactions are difficult to predict. In a subalpine meadow in the Colorado Rocky Mountains, we experimentally removed the flowers of Helianthella quinquenervis, an abundant generalist plant, and found that pollinator visitation declined, visitor composition shifted, and the remaining networks became more specialized, less nested, and less robust to further species loss. This experiment mirrors the floral loss caused by late-spring frost, which damaged flowers more readily than leaves in most of the subalpine plant species we tested.

I am also examining how plant–pollinator interactions reorganize under habitat fragmentation in a scrub ecosystem, even when overall network structure remains similar, and I contribute to collaborative syntheses on the temporal scale-dependence of plant–pollinator networks and global patterns of specialisation.

SELECTED PUBLICATIONS

Bain, J.A. et al. 2022. Removing flowers of a generalist plant changes pollinator visitation, composition, and interaction network structure. Ecosphere.

CaraDonna, P.J. & Bain, J.A. 2016. Frost sensitivity of leaves and flowers of subalpine plants is related to tissue type and phenology. Journal of Ecology.

Sakhalkar, S.P. et al. 2026. Global patterns in plant–pollinator specialisation. Nature Ecology & Evolution.

Schwarz, B. et al. 2020. Temporal scale-dependence of plant–pollinator networks. Oikos.

Bain, J.A. et al. In prep. Plant–pollinator interactions reorganize under habitat fragmentation despite similar network structure.

Wild bees rely entirely on floral pollen and nectar for food, yet plant species differ widely in the protein, lipid, and carbohydrate they provide. I combine long-term plant–pollinator interaction data with macronutrient analyses of field-collected pollen and nectar to quantify the nutritional landscape available to wild bees and the nutrient niches they occupy within it. In the Colorado Rocky Mountains, we found that pollen macronutrient composition shifts over the season and that co-occurring bumble bee species partition two distinct macronutrient niches, associated with differences in feeding morphology and colony life stage.

Building on this work, I am examining how nutrient landscapes structure entire plant–pollinator networks, how bumble bee nutrient niches vary across space in Oklahoma, and, at Penn State, how pollen nutrition shapes bumble bee foraging, diversity, and health.

SELECTED PUBLICATIONS

Bain, J.A. et al. 2025. Nutrient niche dynamics among wild pollinators. Proceedings of the Royal Society B.

Kirschke, G.E.* et al. 2025. A practical roadmap for sampling floral nectar from communities of many plant species. bioRxiv (in revision, Journal of Pollination Ecology).

Heiling, J.M. et al. 2026. The pollen-reward strategy: the paradoxical realities of trading gametes for sex. Annual Review of Ecology, Evolution, and Systematics (in press).

Bain, J.A. et al. In prep. The effects of macronutrients on the emergent properties and species roles within plant–pollinator interaction networks.