Cactoblastis Cactorum - Reproduction and Lifespan

Reproduction and Lifespan

Cactoblastis cactorum mating occurs before sunrise. Mates are found by scent rather than sight. Once a female finds a mate, she begins to release sex pheromones that signal to males her readiness. When the male responds, the mating process is initiated.

The initial process of mating begins when the female and male attach themselves at their abdomens. The male passes a sac, known as the "spermatophore", and the female stores the sac in her abdomen’s reproductive center. After an incubation period, the female deposits an "egg stick" that contains 30–50 eggs. The eggs are laid on either the tip of the cactus spine, the cactus leaf, the cladode, or the cactus fruit.

Egg sticks that resemble cactus spines develop and hatch in 25–30 days. The gregarious larvae bore into the cactus pad through a single entry hole by chewing through the tough outer cuticle of the cladode. The external damage that results is characterized by yellowed plant tissue with plant fluid ooze and insect frass. The larvae feed inside the cactus and eventually hollow out the cactus pad, eventually consuming everything but the vascular tissues.

Larvae will typically spend two months within the host cactus during the summer, and approximately four months during the winter. Mature larvae exit the cactus pad to form cocoons. They pupate under debris on the ground at the base of the plant. As soon as the moths emerge, they search a mate, and usually reproduce three to four times within their lifetime. The average longevity is nine days for females and eleven days for males. During this time, the female moth does not eat; she uses all of her energy to travel up to 10 kilometres (6 mi) in search of dense cactus patches for reproduction. The male moth devotes his energy to maximizing his mating opportunities. Males mate between two to five times, and wait two to three days on average between mating events.