Intersexual and intrasexual patterns of horn size and shape variation in the European rhinoceros beetle: quantifying the shape of weapons
Jakub Goczał , Robert Rossa , Adam Tofilski
AbstractThe weapons of beetles are well-known examples of sexually selected traits that have been studied intensively since the time of Darwin. Although the patterns of variation in weapon size are well known in many species, weapon shape remains very much understudied. This might be a result of technical problems related to quantification of the shape of some types of weapons. Given that description of the patterns of variation in weapon shape is a key step to the proper understanding of the function and evolution of these structures, the main aim of this study was to quantify, for the first time, the inter- and intrasexual patterns of horn shape variation in the European rhinoceros beetle, Orcytes nasicornis L. We documented significant differences in horn shape allometry patterns between male morphotypes. We found that in males of the studied species, the horn becomes more elongated, more curved and more slender with increasing body size, which might potentially support its effectiveness as a weapon used in a specific form of combat of rhinoceros beetles. Nevertheless, when the body reached a critical size (big ‘alpha’ males), no further effect of body size on horn shape was observed. In order to describe horn shape quantitatively, we have developed and tested a simple tool that can be used to quantify various morphological structures, including different types of beetle weapons.
|Journal series||Biological Journal of the Linnean Society, ISSN 0024-4066, e-ISSN 1095-8312, (N/A 70 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||geometric morphometrics, horns, rhinoceros beetle, sexual selection, shape, weapons|
|Publication indicators||= 0; : 2018 = 0.989; : 2018 = 2.203 (2) - 2018=2.243 (5)|
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