DOI: 10.1101/476374Nov 27, 2018Paper

Temporal shifts in intraspecific and interspecific diet variation: effects of predator body size and identity across seasons in a stream community

BioRxiv : the Preprint Server for Biology
Landon P FalkeDaniel L Preston

Abstract

Intraspecific variation is increasingly recognized as an important factor in ecological interactions, sometimes exceeding the role of interspecific variation. Few studies, however, have examined how intra- versus interspecific variation affect trophic interactions over time within a seasonally dynamic food web. We collected stomach contents from 2,028 reticulate sculpin ( Cottus perplexus ), 479 cutthroat trout ( Oncorhynchus clarkii clarkii ), and 107 Pacific giant salamanders ( Dicamptodon tenebrosus ) in western Oregon streams and compared diets among predator species and size classes over three seasons. Predator body size and species identity both showed strong effects on dietary niche breadth, proportional prey composition, and prey size, with seasonal variation in the relative magnitudes of intraspecific and interspecific diet variation. Size-associated diet variation was high in summer and fall but was heavily outweighed by species-associated diet variation in spring. This pattern was driven primarily by a 50-fold increase in the consumption of terrestrial thrips (Order: Thysanoptera) by cutthroat trout in spring compared to summer and fall. Mean dietary niche breadth generally increased with body size and was roughly ha...Continue Reading

Related Concepts

Cell Differentiation Process
Diet
Food
Reptiles
Salamanders
Pacific Islander Americans
Thysanoptera
Salmo clarki
Cottus perplexus
Size

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