Data from: Eutrophication and predation risk interact to affect sexual trait expression and mating success

Cothran, Rickey Duane, University of Pittsburgh

Stiff, Andy R, University of Pittsburgh

Jeyasingh, Punidan D, Oklahoma State University

Relyea, Rick A, University of Pittsburgh

Published Sep 22, 2011 on Dryad. https://doi.org/10.5061/dryad.r471vs43

Cite this dataset

Cothran, Rickey Duane; Stiff, Andy R; Jeyasingh, Punidan D; Relyea, Rick A (2011). Data from: Eutrophication and predation risk interact to affect sexual trait expression and mating success [Dataset]. Dryad. https://doi.org/10.5061/dryad.r471vs43

Abstract

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.

Usage notes

Morphology Data

Collected 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 data

data 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 tradeoff

Family 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 data

Female 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 data

Growth 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).