Luring cannibal: dishonest sexual signalling in the springbok mantis

Sexual signals that attract the opposite sex are typically honest
indicators of quality. However, sexually antagonistic selection can favour
dishonest signals if poor quality members of the signalling sex can
improve their own fitness at a cost to the opposite sex by conveying
deceptive information in their signals. Here, using the sexually
cannibalistic mantis Miomantis caffra, we found evidence that
females in low body condition use sexual deception to exploit males as
prey. Females of high condition produced 97% heavier oothecae than
low-condition females, indicating that high-condition females were the
optimal choice for males. However, in a simultaneous mate choice
experiment using a T-maze olfactometer, males chose the pheromonal signals
of low-condition females twice as often as those of high-condition
females, indicating that female pheromonal attractiveness did not match
female quality. In subsequent mating experiments, low-condition
females attacked males 3 times more frequently and cannibalised them 4
times more often than high-condition females did. Cannibalism provided
significant material benefits for females of low condition, since oothecae
produced by these females were 52% heavier when they cannibalised a male
compared to when they did not. These results strongly suggest
that low-quality females attract males dishonestly with their pheromones
to boost fecundity through sexual cannibalism. Such deception could be
widespread in sexually cannibalistic systems, especially if pheromone
production is cheap, food limitation is common, and males represent a
substantial meal for hungry females.