Alexander Karnish: Moving Past the Net Effect

OPEN TO THE PUBLIC | Mutualisms, like pollination and seed dispersal, are foundational drivers of population and community dynamics. While textbooks often portray these interactions as purely beneficial, the net outcomes for organisms are actually a complex balance between the costs and benefits of participating.

Historically, the costs of mutualism have been overlooked because they are often less visible and harder to quantify than the rewards. However, neglecting costs obscures the underlying mechanisms of interaction stability: both costs and benefits can change independently in response to biotic or abiotic contexts, producing similar net benefits through different selective pressures.

In this talk, I will use two drastically different mutualistic systems—ant seed dispersal and marine cleaning—to underline the importance of measuring both costs and benefits and illustrate how changes in both can shift the outcome of an interaction.