Altered interactions under poleward expansions

Human activity is causing poleward shifts in species, but not all species move in concert, and range-expanding species may arrive in less diverse communities at the poles. Our team studies these altered interactions using a community of oak gall wasps and their parasitoid enemies on Quercus garryana across a latitudinal gradient in western North American oak savannas, leveraging a poleward range expansion of one gall wasp species as a natural experiment. Surveying 500 trees from California to British Columbia, we found that latitudinal diversity gradients create "niche opportunities" for the range-expanding species: weaker local competition, since northern populations lack galls with similar traits (Jones et al. 2022, J. Anim. Ecol.), and altered enemy communities, where loss of interactions with generalist (rather than specialist) enemies likely drives this ecological release (Prior et al. 2023, Diversity & Distributions). We combine large-scale field surveys and experiments, molecular work, and network analyses to trace how these interactions reshape communities as species move. Current work examines whether generalist parasitoids fail to shift from co-occurring gall wasps to the range-expanding species in the expanded range, and whether that failure stems from a mismatch in traits and phenology. We're also examining how reduced host-plant population diversity plays into this story, uncovering the role of altered tritrophic interactions in the range-expanding species' increased success.

This project is funded by the National Geographic Society, the National Science Foundation (DEB 1934387), and a Beagle Award to Charlie Fridrich.

oak gall wasp-parasitoid interactions on Q. garryana

Influence of traits on ecology & evolution of species interactions

More broadly, we use oak gall wasps and their natural enemies to ask what traits shape insect-enemy interactions in general. North American oak gall wasps produce galls with a striking diversity of morphology, including sizes, shapes, and features, such as hairs, internal space, spines, and nectaries, and as part of a collaborative effort, we're working to uncover how these traits shape the ecology and evolution of interactions with natural enemies, including parasitoids and inquilines (Zhang et al. 2022, Molecular Ecology; Ward et al. 2024, Evolution). Building on this, an ongoing NSF-funded project uses citizen science and other data to score traits, including gall morphology and phenology, across hundreds of species continent-wide, asking how traits and evolutionary history shape parasitoid evolution and community assembly. This extends our range-expansion questions about how traits moderate novel interactions into a general framework for trait-mediated species interactions. We are collaborating with the Forbes, Hood, and Nastasi labs on this project.

This project is funded by the National Science Foundation (DEB 2418252).

Land-use change, seed dispersal, and restoration

About a third of understory plants in eastern North American forests depend on ants for seed dispersal, a mutualism called myrmecochory. Ants in the genus Aphaenogaster are the primary dispersers, and our work shows that disrupting their role, including through invasion, reduces seed dispersal and shifts plant communities (Prior et al. 2015, Proc. B; Prior et al. 2020, J. Anim. Ecol.). Land-use change is another major disruption: over 90% of eastern forests were cleared for agriculture at some point, and while the overstory recovered, the understory, especially myrmecochorous wildflowers, did not. Buono et al. (2023, Ecology) found that seed dispersal in regenerated secondary forests is inconsistent, though always intact in primary forests, suggesting restoration should target sites with high dispersal potential. Parker et al. (2021, Ecosphere) and Farrell et al. (2026, Biodiversity and Conservation) further found that forest edges, especially agricultural edges, reduce dispersal. Together, these findings show that dispersal is variable in contemporary forests and should inform restoration planning.

This has led us to actively restore wildflower populations in secondary forests, including in NY State Parks, where we're testing how mutualist ants, and antagonists like deer, rodents, and an invasive slug (Meadley Dunphy et al. 2016, Oecologia; Tan et al. 2023, Acta Oecologia), affect restoration success.

Learn more about our restoration project and collaboration with NY State Parks here.

This project is funded by a Provost Award for Research: Sustainable Communities from Binghamton University and a Phipps Botany in Action Award to Rosebelle Ines

forest wildflowers with seeds with elaiosomes that ants disperse

wildflower restoration

non-native slug damages seeds

Intra- to interspecific variation in traits and function

population variation in the Aphaenogaster species complex

mesocosms to uncover ants' effects on plant communities

Aphaenogaster seed dispersers form a taxonomically unresolved species complex. With Tom Powell's lab, we've found that key behaviors don't sort neatly by species but vary along a gradient from intra- to interspecific, with morphologically intermediate colonies showing intermediate behavior (Buono et al. 2022, Insectes Sociaux). We're now asking how additional traits, including those related to species' relationships with climate, such as thermal tolerance, cuticular hydrocarbons, color, and colony structure, are structured across this gradient. Species within the complex differ in thermal sensitivity, and understanding how these traits vary helps us predict how climate change may shift their activity phenology and, in turn, how those shifts could affect the plant communities that depend on them for seed dispersal. We've set up a mesocosm experiment with ant populations to test these effects directly.

This project is funded by a Binghamton University Presidential Diversity Grant and a NATCHANGE award to Chris DeAngelis.

---

Community ecology and invasive species management

We use systematic reviews and meta-analyses to synthesize the invasion ecology literature and inform community management. Our work has tested whether enemy release generalizes as an explanation for invasion success (Prior et al. 2015, Biological Invasions), and whether removing invasive species reliably restores communities, an assumption that doesn't always hold (Prior et al. 2018, Biological Invasions). We're extending this with a new meta-analysis on when and why communities are resilient to invasion.

Specialized mutualisms in a community context

My earlier work examined an obligate ant-plant mutualism in East Africa, where multiple ant symbionts compete for host trees alongside herbivores and other mutualists. We found that a third partner, a scale insect supplementing the ants' carbohydrate rewards, matters as much to the mutualism as the primary nectar reward (Prior & Palmer 2018, Ecology), and that different ant partners impose different costs on their host trees (Milligan et al. 2023, Ecology). This work continues to shape how I think about mutualisms as embedded in, and shaped by, their broader community context.