Female bee with triungulin larvae on her back. These larvae are the result of venereal transmission from a male bee. An adult male Meloe franciscanus . Images provided by J. Hafernik. The beetle larvae aggregate together on the vegetation and mimic the appearance of a female bee.
Male bees confuse the larvae aggregate for a female and attempt to mate.
This results in the larval aggregation attaching to the underside of the male. When the male finally finds a female and mates, the beetle larvae transfer themselves to the female and get transported back to the nest where they feed on the pollen collected by the female for her offspring. Not only does the aggregation of beetle larvae look like the female bee but it was deduced that pheromones were also emitted by the larvae as male bees were observed to land and hover next to groups of larvae before they aggregated. Painted models of the aggregations were also placed nearby and these were ignored by the male bees. The study site was situated in a desert region so it would seem that the mimicry system developed by M. franciscanus enhances its survival in a harsh environment where bee numbers, flowers and flowering frequency are highly variable.