This study sought to shed light on the evolutionary mechanisms behind occurrences of intraspecific variation in visual aposematic signaling, which contradict well-recognized evolutionary theories predicting signal conformity. Using the striped skunk (Mephitis mephitis), which exhibits vast intraspecific variation in its stripe signal, as model aposematic prey, we endeavored to tease apart sources of selection driving and maintaining warning signal variation. To do this, we analyzed striping patterns of museum M. mephitis skins together with estimated specimen habitat characteristics to investigate whether different striped skunk coloration patterns (1) are no longer under intense selection due to fewer contemporary predators, (2) are shaped by different predatory threats, (3) are a compromise between conspicuousness up close and crypsis at a distance, (4) are impacted by predator desperation at times of palatable prey scarcity, such as harsh winters, (5) vary with humidity (Gloger’s law predicts darker pelage with increasing humidity), or (6) vary with urbanization, which is frequently shown to have effects on nearby wildlife. Analyses revealed that M. mephitis stripes show increased variation in dorsal whiteness as predation pressure decreases, suggesting relaxed selection on signal consistency with decreases in predatory pressure. Stripes were also shown to decrease in amount of overall dorsal whiteness with increasing relative humidity, thus following Gloger’s rule.
|Commitee:||Caro, Tim, Carter, Ashley|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 58/05M(E), Masters Abstracts International|
|Keywords:||Antipredator, Aposematism, Defense, Pelage, Signal, Striped skunk|
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