Geometric morphometric analysis of the male and female body shape of Amblyomma gemma, A. variegatum and A. hebraeum

Abstract

A geometric morphometric analysis of the male and female body shape of three species belonging to the Ixodidae, Amblyomma gemma Dönitz, A. variegatum (Fab.) and A. hebraeum Koch, was performed. These three species are very similar in adult appearance and their distributions overlaps, covering virtually all of sub-Saharan Africa. This analysis compares the body shape of the ticks with each other by collecting 17 landmarks from the ventral area of males and females and analyzing these with geometric morphometrics. Relative warp analyses were performed on the male and female data sets and the results of the first two relative warps (for each of the male and female data sets) were plotted against one another. The first two relative warps are indicative of most variation between structures that were studied. Thin-plate spline analyses were also performed on the consensus shape of the males and females. Results from thin-plate spline analysis indicate which landmarks are responsible for shape variations. Results from the analysis indicate that the body shapes of A. gemma and A. variegatum females cannot be distinguished from each other. The male body shape of the two species is also very similar, as indicated by the consensus thin-plate splines.