How do predators mate?
The female mantis is known for occasionally biting the head off a male and making a meal from the remainder of his body. Even though the male can successfully mate without his head, it will be his last act. Communication is critical for the male mantis. Males need to know in advance if the female mantis is looking for a mate or looking for a meal. Since there is no Facebook for a Mantis, other means of communication are necessary.
For quite some time, it has been suspected that females of some species of mantis produce a sex attractant pheromone. In 2004, scientists identified the first pheromone from a female mantis, Sphodromantis lineola. The pheromone consists of two aldehydes, n-tetradecanal and n-pentadecanal. These 2 chemicals will attract male mantids. More recently, Beatriz Perez described a calling behavior in the female mantis, Hierodula patellifera.
Females who are ready to mate will bend the tip of their abdomen downward, exposing areas of the exoskeleton between plates on top of the abdomen. It is suspected that the area between the plates contains glandular tissue. Bending the abdomen exposes the gland and releases the pheromone.
A female mantis has cryptic coloration, blends into its environment, and may be relatively rare. Pheromone release would help males locate a suitable mate in a complex environment with low densities of females. If the female mantis only releases pheromone when she is in the mood for mating and not when she is interested in eating, then males can approach for mating in relative safety.