Prey capture behavior in three Neotropical armored harvestmen (Arachnida, Opiliones)

Acquiring food requires success in all the distinct phases of foraging, among which are detecting, capturing and handling prey. We have looked at prey detection, capturing and handling in three species of armored harvestmen differing in leg length and pedipalp morphology: Discocyrtus pectinifemur, Heteromitobates discolor and Gryne perlata. We recorded males and females in captivity capturing 0.5- to 0.7-mm-long immature crickets without legs III and provide the first detailed description of prey capture in harvestmen of the suborder Laniatores. We have shown that these three species can detect live prey without touching it but only at close range (< 1 cm). The success at the strike phase was: 27.2 % for D. pectinifemur, 50 % for G. perlata and 72.7 % for H. discolor. Combining the probability of detection without contact with that of successful capturing of the two-legged cricket, the success rate of G. perlata, D. pectinifemur and H. discolor were, respectively, 2, 21 and 32 %. Only one cricket escaped from within the pedipalps of the harvestmen (G. perlata, smooth pedipalps). The long-legged H. discolor, which forage in open areas, had a higher success and, after detection, took less time to attack crickets in open areas. Compared to other arachnids, prey detection happens at close range and capture success in Laniatores is low. However, omnivory probably minimizes these limitations in capturing live prey.