Research

Species interactions and biodiversity in a changing world

Sun lab is interested in the interface of ecology and evolution in a human-modified world. Our research focuses on the evolutionary processes driving adaptation to new environments, and the ecological drivers of variations in biotic interactions, which in turn shape the responses to changing environments.

Impacts of multiple environmental stressors on biotic interactions and ecosystem functions

Sun (2022)

In a rapidly changing world, human population growth and economic activities have caused environmental stressors that animals have never before encountered. How do these climate change variables, such as warming, habitat loss, and invasive species, affect natural populations? More commonly, these stressors do not simply act in isolation but can interact to affect individuals, populations, and communities. We aim to understand how animal respond to multiple environmental stressors, particulalry through interactions within and between species, cascading to determine community structure and ecosystem functions. 

The mutualism-parasitism continuum

The outcomes of species interactions are not stable and can vary from space and time. Mutualisms and parasitisms, in particular, can change in their effects on host species, even within the same pair of interacting species. We aim to explore the underlying mechanisms driving these transitions, both ecological and evolutionary, and the environmental contexts they depend upon. Moreover, our goal is to investigate the knock-on effects of mutualism-parasitism continuum on structuing communities and ecosystem functions. 

Sun (2019)

Study systems

Burying beetles as ecosystem engineers

We focus on burying beetles as model systems because they are not only fascinating in their behaviour, ecology, and evolution, but also because they are sensitive to environmental changes and play critical roles in supporting ecosystem functions, such as waste removal, nutrient cycling, and pest control.  

Burying beetles

A female is feeding its young inside an edible carcass nest prepared by itself after removing fur, folding as a ball, and burying it underground. Photo by S.-J. Sun.

Phoresy: a new model for studying species interactions



Burying beetles and phoretic mites

While beetles fly to search for breeding resources, which many species also depend upon for a living, mites can't. They are termed 'phoretic' as they hitch a ride on the host, being transported across resource patches. 

However, these phoretic species are under-studied, and are commonly believed to be commensal, causing no direct fitness effects to the hosts. Strikingly, we showed that the interactions between beetles and mites are on a spectrum of mutualism and parasitism, depending on various ecological and social environments (Sun and Kilner 2020 eLife; Sun et al. 2019 Evolution Letters).

By combining large-scale field experiments and laboratory experimental coevolution, we are interested to know: