Uncertainty about flying conspecifics causes territorial contests of the Old World swallowtail, Papilio machaon.

BACKGROUND: Male-male aerial contests of territorial butterflies are difficult to explain by major contest models based on game theory because of butterflies' apparent inability to inflict substantial costs on their opponent. As an alternative, the "erroneous courtship hypothesis" was presented. This hypothesis is based on the assumption that territorial butterflies cannot discriminate the sex of flying conspecifics. The hypothesis regards the aerial contest of male butterflies as an inevitable same-sex entanglement in the butterflies' behavioral sequence. To test the robustness of the hypothesis, we investigated the sex recognition abilities of the Old World swallowtail, Papilio machaon. RESULTS: We presented four types of flapping butterfly specimens (fresh male and female, chemicals-removed male and female) to territorial males. The males touched fresh female specimens and showed typical courtship flight. For the other types of specimens, they rarely showed courtship flight although they approached or touched them. In addition, territorial males reacted longer to fresh males than to fresh females. CONCLUSIONS: The results indicated that although territorial males recognize flying females as sexual partners by sensing their semiochemicals, they cannot identify flying conspecific males, and continue to gather information on them. P. machaon is one of the species whose behavior is most incompatible with the erroneous courtship hypothesis, as its males perform a typical courtship flight to flying females, suggesting the ability of sexing flying conspecifics. Nevertheless, the erroneous courtship hypothesis was not disproved by our results.

Effect of Canine Oxytocin Receptor Gene Polymorphism on the Successful Training of Drug Detection Dogs.

Drug detection dogs can be trained to locate various prohibited drugs with targeted odors, and they play an important role in the interdiction of drug smuggling in human society. Recent studies provide the interesting hypothesis that the oxytocin system serves as a biological basis for co-evolution between dogs and humans. Here, we offer the new possibility that genetic variation of the canine oxytocin receptor (OXTR) gene may regulate the success of a dog's training to become a drug detection dog. A total of 340 Labrador Retriever dogs that were trained to be drug detection dogs in Japan were analyzed. We genotyped an exonic SNP (rs8679682) in the OXTR gene and compared the training success rate of dogs with different genotypes. We also asked dog trainers in the training facility to evaluate subjective personality assessment scores for each dog and examined how each dog's training success was related to those scores. A significant effect of the OXTR genotype on the success of the dogs' training was found, with a higher proportion of dogs carrying the C allele (T/C and C/C genotypes) being successful candidates than dogs carrying the T/T genotype. Dog personality scores of Training Focus (Factor 1) were positively correlated with an increased likelihood that a dog would successfully complete training. Although the molecular mechanism of the OXTR gene and its functional pathway related to dog behavior remains unknown, our findings suggest that canine OXTR gene variants may regulate individual differences between dogs in their responsiveness to training for drug detection.