Abstract
Cross recognition of host marking pheromones (HMP) has been reported among different groups/species of insects but is still a poorly understood phenomenon. Here, using electrophysiological and behavioral bioassays we compared the cross-recognition response of eight Anastrepha species (belonging to different groups in the phylogenetic tree of the genus) to each other's feces extracts (putatively including host marking pheromones) and to feces extracts of Ceratitis capitata and two Rhagoletis species (pomonella and cerasi). We also tested the response of C. capitata to Anastrepha spp. feces extracts. For electrophysiology, solutions of sucrose or KCl were used as positive and negative stimuli respectively. Behavioral bioassays (including natural marks) indicated complete HMP cross recognition (i.e., "Discrimination Coefficient" of more than 50%) among the four Anastrepha species tested. Furthermore, lower but still positive responses were observed in C. capitata females when exposed to the HMP of A. ludens, A. serpentina and A. obliqua. However, only A. serpentina females responded to C. capitata feces extracts in the behavioral bioassays. Electrophysiology tests demonstrated that A. ludens females recognized the HMP of seven congeners including the non-marking ones A. curvicauda and A. bezzii. Additionally, A. ludens, A. obliqua and A. serpentina females responded to male A. ludens feces extracts. Finally, A. serpentina male feces extracts elicited electrophysiological response in females of A. serpentina or A. striata. These results indicate that, in Anastrepha, HMP is produced by females and males, including females of species which do not exhibit the typical marking behavior of dragging their aculeus. We discuss the possibility that the HMP in Anastrepha is an exaptation.