Cannibalistic mating in mantids Mantodea

The sex life of mantids is the subject of some controversy, partly as a consequence of behavioral observations made under unnatural conditions in the laboratory. For example, there are many reports of the male being eaten by the generally larger female before, during, or after mating. Males decapitated by females are even known to copulate more vigorously because of the loss of the sub-oesophageal ganglion that normally inhibits copulatory movements. Sexual cannibalism has been attributed to food deprivation in confinement but female mantids of at least some species may indeed eat their partners in the wild.

Courtship displays may be complex or absent, depending on species, but generally the female attracts the male via sex pheromones and visual cues. Typically, the male approaches the female cautiously, arresting movement if she turns her head towards him, and then he leaps onto her back from beyond her strike reach. Once mounted, he crouches to elude his partner's grasp. Copulation usually lasts at least half an hour and may continue for several hours, during which sperm are transferred from the male to the female in a spermatophore. After mating, the male retreats hastily. If the male were in no danger of becoming the female's meal, his distinctive behavior in the presence of the female would be inexplicable. Furthermore, suggestions of gains in reproductive fitness of the male via indirect nutritional benefits to his offspring are negated by the obvious unwillingness of the male to participate in the ultimate nuptial sacrifice: his own life!

Whereas there is no evidence yet for an increase in male reproductive success as a result of sexual cannibalism, females that obtain an extra meal by eating their mate may gain a selective advantage, especially if food is limiting. This hypothesis is supported by experiments with captive females of the Asian mantid Hierodula membranacea that were fed different quantities of food. The frequency of sexual cannibalism was higher for females of poorer nutritional condition and, among the females on the poorest diet, those that ate their mates produced significantly larger oothecae (egg packages) and hence more offspring. The cannibalized males would be making a parental investment only if their sperm fertilize the eggs that they have nourished. The crucial data on sperm competition in mantids are not available and so currently the advantages of this form of nuptial feeding are attributed entirely to the female.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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