DOI: 10.5061/dryad.r471vs43
title: Data from: Eutrophication and predation risk interact to affect sexual trait expression and mating success

description: Sexual traits are especially sensitive to low food resources. Other
 environmental parameters (e.g., predation) should also affect sexual trait
 expression by favoring investment in viability traits rather than sexual
 traits. We know surprisingly little about how predators alter investment
 in sexual traits, or how predator and resource environments interact to
 affect sexual trait investment. We explored how increasing phosphorous (P)
 availability, at a level mimicking cultural eutrophication, affects the
 development of sexual, non-sexual, and viability traits of amphipods in
 the presence and absence of predators. Sexual traits and growth were
 hyper-sensitive to low P compared to non-sexual traits. However, a key
 sexual trait responded to low P only when predator cues were absent.
 Furthermore, investment tradeoffs between sexual traits and growth only
 occurred when P was low. The phenotypic changes caused by predator cues
 and increased P availability resulted in higher male mating success. Thus,
 eutrophication not only affects sexual trait expression but also masks the
 tradeoff between traits with similar P demand. Sensitivity of sexually
 selected traits to changes in P, combined with the important roles these
 traits play in determining fitness and driving speciation, suggests that
 human-induced environmental change can greatly alter the evolutionary
 trajectories of populations.
description: Morphology
 DataCollected from the
 experiment. Measurements were taken using an imaging system. The file was
 created using Numbers for Mac. LF=low phosphorus, HF=high phosphorus;
 P=predator cues, NP=no cues; head=head length, antenna= antenna length,
 a_gnath= anterior gnathopod width, p_gnath=posterior gnathopod width.
 Missing data are due to damaged traits.male-male comp
 datadata collected for the
 mate competition experiment. Family, cup (id #), P treatment (high P=HF,
 low P=LF), predator cue (P=predator cue, NP=no cue), head length of focal
 male, posterior gnathopod width of focal male, ln(head length),
 ln(posterior gnathopod), residual gnathopod size (regressed against head
 length), z-score within treatments for head length, z-score within
 treatments for residual gnathopod size.Family means
 tradeoffFamily means for
 tradeoff analysis. Family, P treatment (high P=HF, low P=LF), Predator cue
 (NP=no cue, P=predator cue), residual antenna size (regressed against head
 length), resid posterior gnathopod size (against head length), and growth
 rate (ln-transformed) are provided.Female fecundity
 dataFemale fecundity data.
 Family, Phosphorus treatment (high=high P, low=low P), predator cue
 (p=predator cue, np=no cue), cup (id#), head length, whether the female
 was cannibalized by males, fecundity trait (egg number, egg volume, or
 number of neonates[offsp_nu]), fecundity trait value, ln(head length),
 ln(fecund_value).growth
 dataGrowth rate data. ID
 (individual ID#), family, Phosphorus treatment (high P=HF, low P=LF),
 predator cue(np=no cue, p=predator cue), sex, age in days, growth (growth
 rate [head length/age]), head length (mm), ln(growth
 rate).