Investigation of the effect of sexual cannibalism on sex ratio in a natural population of praying mantis

Sexual cannibalism is the behavior of one sex to consume the other for food, and this event can cause skewed sex ratios within the population. The effect of sexual cannibalism on the sex ratio in the population has not been adequately clarified, and related studies have only been studied on species with similar phenology and known to exhibit sexual cannibalism in nature. The possible effects of cannibalism within the population can be better clarified on species with different phenology and diet. There is no evidence that Empusa fasciata, which has a different phenology from the mantid species studied so far, exhibits cannibalistic behavior in nature. In this study, cannibalism was tested with two different diets and phenologies in Mantis religiosa, where cannibalism is common, and E. fasciata, where cannibalism is common, and sex ratios in natural populations were followed. In captive conditions, 30% cannibalism was observed in M. religiosa, while 7.14% sexual cannibalism was detected in E. fasciata, but in nature, inter-sexual and intra-sexual cannibalisms were observed in M. religiosa, while no evidence of cannibalism was found in E. fasciata. As a result of this study, a male-biased sexual ratio was observed in M. religiosa from the nymphal stage to the reproductive period in the adult stage; During the reproductive period, the male-biased sex ratio suddenly became female-biased. The sexual ratio of E. fasciata, which was close to 1:1 in the nymphal period, shifted to female bias towards the adult stage and continued with female bias in the adult stage. With this result, it can be interpreted that cannibalism in M. religiosa is effective in shaping the sex ratio of the adult population; Biased sex ratio is expected to occur in E. fasciata due to different factors.