Prey identity affects fitness of a generalist consumer in a brown food web

Abstract

The use of ever‐advancing sequencing technologies has revealed incredible biodiversity at the microbial scale, and yet we know little about the ecological interactions in these communities. For example, in the phytotelmic community found in the purple pitcher plant, Sarracenia purpurea, ecologists typically consider the bacteria as a functionally homogenous group. In this food web, bacteria decompose detritus and are consumed by protozoa that are considered generalist consumers. Here, we tested whether a generalist consumer benefits from all bacteria equally. We isolated and identified 22 strains of bacteria, belonging to six genera, from S. purpurea plants. We grew the protozoa, Tetrahymena sp. with single isolates and strain mixtures of bacteria and measured Tetrahymena fitness. We found that different bacterial strains had different effects on protozoan fitness, both in isolation and in mixture. Our results demonstrate that not accounting for the composition of prey communities may affect the predicted outcome of predator–prey interactions.

Predator dispersal influences predator distribution but not prey diversity in pitcher plant microbial metacommunities

“…TA may be dispersal limited because it lacks a life history stage that facilitates dispersal, or its larger size may make it more difficult to take advantage of dispersal vectors, such as wind, water, or insects. In addition, TA may be excluded from newly opened leaves because of either (1) high abundance of mosquito larvae that preferentially prey on larger protozoa (Kneitel, 2012), (2) strong competitive interactions within a leaf (Cochran‐Stafira & Von Ende, 1998; Kneitel & Miller, 2002), or (3) reduced growth rates due to the bacterial species present in the community (Khadempour et al, 2022). Hence, the distribution of a predator in space results from a combination of regional processes of dispersal and local processes that influence successful establishment (Mouquet & Loreau, 2003).…”