Most animals have a body plan that is bilaterally symmetric, at least externally. In some species, however, directional asymmetry (DA) occurs, where there is a preferential ‐ 32 ‐ direction of asymmetries, with one side that differs systematically from the other. Although it was first thought tat DA is relatively rare, subtle DA has been found in all studies that examined asymmetries with geometric morphometric techniques. Until now all the studies have looked at only one structure or at the comparison between modules. Here we analysed directional asymmetries of several different parts showing matching and object symmetries in Paussus favieri (Coleoptera, Carabidae, Paussini). Because beetles of the tribe Paussini are parasites of ants they are of great interest because of the striking myrmecophilous adaptations. Most of the species are extremely rare and localized, and their biology and systematics are still poorly known. We used geometric morphometric techniques to analyze the variation of antennae (both left and right), head, pronotum and abdomen in P. favieri (a relatively common species) from different European and Maghrebian localities. A clear and high evidence of a pattern of directional asymmetry emerged from the analyses in all parts examined. In particular principal component analysis revealed a pattern of variation associated with DA, higher in the antennae, but still present in all other body parts except of the abdomen. In all analyses differences between populations emerged as well. Finally, Procrustes ANOVA provides similar results. For size DA was statistically significant in all body parts except the abdomen. For shape DA was significant only in the antennae. From our analyses antennae have emerged as the part most under the DA, with a high shape and size variability. Moreover differences between populations emerged, with Moroccan population showing the highest differences. We conclude that multiple body parts have directional asymmetry, and the differences find between populations show that directional asymmetry is evolving.
Bravi, R., Scalici, M., Klingenberg, C.p., DI GIULIO, A. (2012). Directional asymmetry in Paussus favieri (Coleoptera: Carabidae: Paussini). In 7ème Symposium Morphométrie et Evolution des Formes (pp.31-32). Pascale CHEVRET, LBBE.
Directional asymmetry in Paussus favieri (Coleoptera: Carabidae: Paussini)
SCALICI, MASSIMILIANO;DI GIULIO, ANDREA
2012-01-01
Abstract
Most animals have a body plan that is bilaterally symmetric, at least externally. In some species, however, directional asymmetry (DA) occurs, where there is a preferential ‐ 32 ‐ direction of asymmetries, with one side that differs systematically from the other. Although it was first thought tat DA is relatively rare, subtle DA has been found in all studies that examined asymmetries with geometric morphometric techniques. Until now all the studies have looked at only one structure or at the comparison between modules. Here we analysed directional asymmetries of several different parts showing matching and object symmetries in Paussus favieri (Coleoptera, Carabidae, Paussini). Because beetles of the tribe Paussini are parasites of ants they are of great interest because of the striking myrmecophilous adaptations. Most of the species are extremely rare and localized, and their biology and systematics are still poorly known. We used geometric morphometric techniques to analyze the variation of antennae (both left and right), head, pronotum and abdomen in P. favieri (a relatively common species) from different European and Maghrebian localities. A clear and high evidence of a pattern of directional asymmetry emerged from the analyses in all parts examined. In particular principal component analysis revealed a pattern of variation associated with DA, higher in the antennae, but still present in all other body parts except of the abdomen. In all analyses differences between populations emerged as well. Finally, Procrustes ANOVA provides similar results. For size DA was statistically significant in all body parts except the abdomen. For shape DA was significant only in the antennae. From our analyses antennae have emerged as the part most under the DA, with a high shape and size variability. Moreover differences between populations emerged, with Moroccan population showing the highest differences. We conclude that multiple body parts have directional asymmetry, and the differences find between populations show that directional asymmetry is evolving.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
