RT Journal Article SR Electronic T1 Integration between swim speed and mouth size evolves repeatedly in Trinidadian guppies and aligns with suction-feeding fishes JF The Journal of Experimental Biology JO J. Exp. Biol. FD The Company of Biologists Ltd SP jeb190165 DO 10.1242/jeb.190165 VO 222 IS 2 A1 Kane, Emily A. A1 Roeder, Megan M. A1 DeRue, McKenna L. A1 Ghalambor, Cameron K. YR 2019 UL http://jeb.biologists.org/content/222/2/jeb190165.abstract AB Well-supported correlations between swim speed and mouth size during prey capture suggest the broad existence of an integrated relationship between locomotion and feeding in suction-feeding fishes. However, the influence of specialization on this relationship is unclear. We used divergent populations of Trinidadian guppies (Poecilia reticulata) to test whether integration during suction is generalizable to a non-suction specialist and whether intraspecific specialization of component systems affects their integration. Guppies from replicate high- and low-predation streams were recorded capturing wild-type zooplankton using suction. Alternative general linear models supported a positive correlation between swim speed and mouth size in derived low-predation populations, suggesting that the relationship can be extended in some cases. High-predation populations lack this integration, which may be the result of direct selection or constraints imposed by selection on locomotion. As guppies invade new habitats they may be evolving a new, integrated performance phenotype from a non-integrated ancestor.