Relating the unique sensory system of amblypygids to the ecology and behavior of Phrynus parvulus from Costa Rica (Arachnida, Amblypygi)

While the unique sensory system and neuroanatomy of amblypygids suggest that olfaction is important in their lives, to date no behavioral data exist to support this suggestion. To gain insight into amblypygid ecology and behavior, an individual mark-recapture study was conducted on the Costa Rican amblypygid Phrynus parvulus. Within two 50 by 25 m plots, the distribution and movement patterns of individual amblypygids were recorded for over 2 months. A total of 88 adult individuals (60 males and 28 females) were marked, with an average 51% resighted. Females were resighted more frequently than males (75% females, 40% males). The sexes did not differ in their frequency or movement distance, but females were more likely to be seen on the same tree over time. While both sexes potentially wander in search of mates, females may also be searching for a good crevice, or diurnal hideout. Once a female has mated and laid eggs, she likely remains stationary. Movement patterns and tree choice seem to be dictated by both the presence of conspecifics and environmental factors such as tree surface area, moss cover, and the presence of buttressing. Cumulative observational data collected over 3 years suggest that the main breeding season for this species is October-January. Both mate attraction and navigation may be facilitated by the olfactory capabilities of amblypygids, while their giant interneurons may be involved in their foraging behavior.