A strong colonizer rules the trematode guild in an intertidal snail host

Inside a snail, trematodes interact with each other with outcomes that depend on facilitation, competition, and preemption, suggesting that dominant species should be common. However, inside the snail host Heleobia australis (Bahía Blanca estuary, Argentina), the weak competitor Microphallus simillimus was the most abundant trematode species. This parasite shows life‐history traits associated with higher colonization ability that could increase its probability of invading the host first. We found that M. simillimus ruled the species‐rich trematode guild through strong recruitment and (potentially) preemption. Extremely skewed species abundance distributions, like this one, can derive from extremely skewed colonization abilities. These photographs illustrate the article “A strong colonizer rules the trematode guild in an intertidal snail host” by Pilar Alda, Nicolás Bonel, Néstor J. Cazzaniga, Sergio R. Martorelli, and Kevin D. Lafferty published in Ecology. https://doi.org//10.1002/ecy.269