Here we want to stress that these two studies agree on a number of points that move detective work on the mystery of zebra stripes forward considerably. That said, these two studies, conducted independently of each other, have now tested a number of hypotheses for the function of striping in zebras, with both studies using a multifactorial approach that pits the hypotheses against each other allowing for direct tests of multiple hypotheses within the same model. Our comparative study pertains to the factors that maintain striping across species of equids, whereas Larison and co-workers' conclusions are specific to the ecocorrelates of variation in striping within plains zebras, and cannot necessarily be extrapolated directly to infer the selective pressures that favoured the original evolution of zebra stripes, which only occurred once in the genus. Our study provided strong evidence that our proxy for tabanid fly parasitism was essentially perfectly correlated with the presence of stripes across species across almost every area of the body, and especially for leg stripes, the level at which biting flies prefer to land on hosts. Further, our study was corrected for phylogenetic relatedness between the species and subspecies, allowing us to draw conclusions about correlated evolution between body striping and environmental selective pressures. First we ran univariate tests on individual factors to identify the hypotheses with the strongest predictive ability, then subsequently used AICc model selection procedures to pit the most promising predictors against each other-a powerful statistical protocol for testing multiple hypotheses. These were camouflage in woodlands, antipredator defence against both lions and spotted hyaenas ( Crocuta crocuta), social interactions, tsetse fly distribution, tabanid distribution using both temperature and humidity ranges as a proxy for abundance, and temperature isoclines to assess the cooling hypothesis. ferus przewalski), and 20 of their subspecies, and compared several aspects of the four hypotheses. Last year we published a similar but phylogenetically controlled analysis using all seven species of equids, namely the three striped zebra species, the African wild ass ( Equus africanus) which has leg stripes but no body stripes, and the unstriped species of equids ( E. They found that greater intensities of intraspecific striping were associated with warmer temperatures and high precipitation. They matched variation in striping patterns at 16 sites across its geographical range to a suite of environmental variables as well as tsetse fly (glossinid) distribution and lion ( Panthera leo) presence. investigated the environmental factors that explain geographical variation in striping within a single species, the plains zebra ( Equus quagga or Equus burchellii). Now, in the second multifactorial analysis of striping in zebras to date, Larison et al. Four major hypotheses have been put forward: stripes are an antipredator defence operating through crypsis or confusion of predators, are a means of reinforcing social bonds, are defence against ectoparasites or are a means of cooling zebras. The functional significance of the extraordinary black and white stripes of zebras is still mysterious but now an active field of research.
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