Parasites are often considered 'bad' but actually they are a natural part of ecosystems and biological diversity. Parasites control host populations, which prevents hosts from becoming excessively abundant. Parasitism is the most common lifestyle on Earth and it may even promote species coexistence and stabilize ecosystems.

The idea is that tropical regions and their native biodiversity are better at resisting invasive species than temperate regions due to high biodiversity and strong biotic interactions like predation, parasitism and competition. We are testing this hypothesis by using the same experiments across a latitudinal framework that has not been applied in marine systems. The fundamental goal is to learn how biotic interactions shape invasions and shape the biodiversity of marine communities in general.

Most people think of parasites and diseases as being detrimental to the overall health of an ecosystem. But researchers are now realizing that parasites and pathogens are consumers that have important roles in ecosystems. When we discuss disease ecology, people tend to focus on emerging diseases or outbreaks in a particular place, not necessarily the underlying infectious processes that connect communities and that might be keeping ecosystems healthy. Parasites and pathogens are normal components of ecosystems and contribute to biodiversity. We are now beginning to ask if it is possible to use parasites to understand fundamental principles in patterns of biodiversity.

Do native predators and parasites control marine invaders? How do consumer interactions, shape the diversity you see on the rocks in the intertidal zone or on tropical or temperate reefs? Are predators and parasites more important in limiting invasions in the tropics compared to higher latitudes? In other words, are you more likely to get eaten in the tropics than in the temperate zone — whether it’s a by parasite, a predator or something that is taking a little bite like a mosquito or a browser like a deer?