DOI: 10.5061/dryad.pc866t1nt
title: Data for Predation and resource availability interact to drive life-history evolution in an adaptive radiation of livebearing fish

description: Predation risk and resource availability are two primary factors predicted
 by theory to drive the evolution of life histories. Yet, disentangling
 their roles in life-history evolution in the wild is challenging because
 (1) the two factors often co-vary across environments and (2)
 environmental effects on phenotypes can mask patterns of genotypic
 evolution. Here, we use the model system of the Post-Pleistocene radiation
 of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes to provide
 a strong test of the roles of predation and resources in life-history
 evolution, as the two factors do not co-vary in this system and we
 attempted to minimize environmental effects by raising eight populations
 under common laboratory conditions. We tested a priori predictions of
 predation- and resource-driven evolution in five life-history traits. We
 found that life-history evolution in Bahamas mosquitofish largely
 reflected complex interactions in the effects of predation and resource
 availability. High predation risk has driven the evolution of higher
 fecundity, smaller offspring size, more frequent reproduction, and slower
 growth rate—but this predation-driven divergence primarily occurred in
 environments with relatively high resource availability, and the effects
 of resources on life-history evolution was generally greater within
 environments having high predation risk. This implies that resource-driven
 selection on life histories overrides selection from predators when
 resources are particularly scarce. While several results matched a priori
 predictions, with the added nuance of interdependence among selective
 agents, some did not. For instance, only resource levels, not predation
 risk, explained evolutionary change in male age at maturity, with more
 rapid sexual maturation in higher-resource environments. We also found
 faster (not slower) juvenile growth rates within low-resource and
 low-predation environments, probably caused by selection in these
 high-competition scenarios favoring greater growth efficiency. Our
 approach, using common-garden experiments with a natural system of low-
 and high-predation populations that span a continuum of resource
 availability, provides a powerful way to deepen our understanding of
 life-history evolution. Overall, it appears that life-history evolution in
 this adaptive radiation has resulted from a complex interplay between
 predation and resources, underscoring the need for increased attention on
 more sophisticated interactions among selective agents in driving
 phenotypic diversification.
description: Methodological details are provided in the paper. Briefly, the
 data comprise life-history variables measured for lab-raised fish derived
 from 8 wild populations (Bahamian blue holes) of Bahamas mosquitofish
 (<em>Gambusia hubbsi</em>). The data come from common-garden
 experiments conducted with multiple generations of fish.
description: The data file has 5 separate sheets, each containing data for
 separate analyses performed in the study. Missing data are indicated with
 blank cells. Sheet 1: Fecundity-Lab&Wild:
 Fecundity (number of offspring per brood) and body size (standard length,
 mm) data for females either collected in the wild or raised in the lab for
 each of 8 populations of Bahamas mosquitofish. Sheet 2:
 Lab Fecundity, Offspring Size, and Interbrood Interval: The number of
 offspring per brood, average standard length of offspring at birth (mm),
 and the number of days between parturitions of offspring for two
 generations of lab-raised fish from 8 populations. Also included are the
 Female IDs, body size of female, brood number (sequential order of broods
 per female), and information for the predation regime and resource
 availability of each population. Sheet 3: Male Age at
 Maturity: The age at maturity of males (number of days of age when
 gonopodium tip fully formed), Brood IDs, average water temperature, and
 information for the predation regime and resource availability of each
 population. Sheet 4: Juvenile Growth Rate: The 2-month
 growth rate (mm/day), average water temperature, Brood IDs, tank density
 (# fish per 10L tank), experimental temporal block, and information for
 the predation regime and resource availability of each
 population. Sheet 5: Lab Population Means: Adjusted
 average trait values for each population for the 5 life-history traits, as
 well as PC scores from the first 2 PC axes derived from a PCA conducted on
 the correlation matrix of the 5 traits.