Phenotypic plasticity is advantageous for organisms that live in variable environments. The digestive system is particularly plastic, responding to changes in diet. Gut length is the result of a trade-off between maximum nutrient absorption and minimum cost for its maintenance and it can be influenced by diet and by evolutionary history. We assessed variation in gut length of Trinidadian guppies (Poecilia reticulata) as a function of diet, season, ontogeny, and local adaptation. Populations of guppies adapted to different predation levels have evolved different life history traits and have different diets. We sampled guppies from sites with low (LP) and high predation (HP) pressure in the Aripo and Guanapo Rivers in Trinidad. We collected fish during both the dry and wet season and assessed their diet and gut length. During the dry season, guppies from HP sites fed mostly on invertebrates, while guppies in the LP sites fed mainly on detritus. During the wet season, the diet of LP and HP populations became very similar. We did not find strong evidence of an ontogenetic diet shift. Gut length was negatively correlated with the proportion of invertebrates in diet across fish from all sites, supporting the hypothesis that guppy digestive systems adapt in length to changes in diet. Population of origin also had an effect on gut length, as HP and LP fish maintained different gut lengths even in the wet season, when their diets were very similar and individuals in both types of populations fed mostly on detritus. Thus, both environment and population of origin influenced guppies gut length, but population of origin seemed to have a stronger effect. Our study also showed that, even in omnivorous fish, gut length adapted to different diets, being more evident when the magnitude of difference between animal and plant material in the diet was very large.
Contrasting Population and Diet Influences on Gut Length of an Omnivorous Tropical Fish, the Trinidadian Guppy (Poecilia reticulata)
Creators
Eugenia Zandona - Drexel University
Sonya K. Auer - University of California, Riverside
Susan S. Kilham - Drexel University
David N. Reznick - University of California, Riverside
Publication Details
PloS one, v 10(9), pp e0136079-e0136079
Publisher
Public Library Science
Number of pages
18
Grant note
EF-0623632 / National Science Foundations Frontiers in Integrative Biological Research program
Betz Chair of Environmental Science at Drexel University
Joseph Mozino scholarship
Resource Type
Journal article
Language
English
Academic Unit
[Retired Faculty]
Web of Science ID
WOS:000361043100008
Scopus ID
2-s2.0-84959432092
Other Identifier
991019167562504721
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