Fatal Attraction: Spiders Lure Male Moth Prey with the Promise of Sex.

Predator-prey coevolution, particularly chemo-ecological arms races, is challenging to study as it requires the integration of behavioral, chemical ecology, and phylogenetic studies in an amenable system. Moths of the genus (Saturniidae) are colorful, diurnal, and fast and often fly well above the vegetation canopy layer. However, several species have been reported as being captured in spider webs, specifically species (Araneidae). Female are known to produce mating pheromones and spiders of the Araneidae family are known to use pheromone lures to attract lepidopteran prey. We presented primarily female , which are attractive to male (Saturniidae), to different populations of species across the southern and western United States to categorize the homing response strength of different species of male . When we mapped these lure attraction strength categories onto the most recently published phylogeny, the behavioral patterns suggested a potential co-evolutionary arms race between predators and prey. Males of , , and (all in the same clade) appeared to have no attraction to , while and (within a different, separate clade) appeared to be strongly attracted to , but (also within the and clade) displayed no attraction. Furthermore, (yet a different clade) displayed strong, weak, and no attraction to , depending on the population. These apparent clade partitioning patterns of lure effectiveness and within-species variation in lure responses suggest a predator-prey coevolutionary history of measures and countermeasures.