An ethological approach to a SEM survey on sensory structures and tegumental gland openings of two neotropical harvestmen (Arachnida, Opiliones, Gonyleptidae)

Abstract

We studied the sensory structures and tegumental glands of two harvestmen species, Neosadocus sp. and Iporangaia pustulosa. We also provide field data of dietary items and data on the foraging behavior of Neosadocus sp. in captivity. Food include mostly immobile items such as dead insects, fruits and feces; the mobility of foraging animals in starvation was greater than in satiation conditions; no trichobothria was found; metatarsal paired slit sensilla and three other sensilla are described for the first time in harvestmen. We discuss the possible relationship between sensory structures, diet and foraging mobility, comparing with other groups of Arachnida. We also describe five new tegumental glands, one sexually dimorphic in the metatarsus IV of I. pustulosa males and two that are rubbed against the substrate while walking, present in both species. This is the first morphological evidence that harvestmen might leave chemical marks on the substrate.