Behavioral Repertory of the Neotropical Harvestman Ilhaia Cuspidata (opiliones, Gonyleptidae)

In this study, we provide an ethogram for the harvestman Ilhaia cuspidata and describe the daily activity pattern of captive individuals. We also provide a comparison between the behavioral repertory of this species with that of the syntopic Discocyrtus oliverioi. Five females and four males of I. cuspidata were maintained in the same terrarium from November 1999–November 2000 for qualitative and quantitative observations. Twenty behavioral acts were recorded, classified in seven categories and the relative frequency of each was determined: exploration (69.8%), resting (16.7%), feeding (6.3%), grooming (4.4%), social interactions (2.6%), reproduction (0.1%) and others (0.3%). There was a marked difference in the frequency of the behavioral categories between sexes: females fed more frequently than males and males were involved in social interactions more frequently than females. During most of the daylight hours, individuals remained inside shelters and became active from 19:00–09:00 h. Although I. cuspidata and D. oliverioi showed almost the same behavioral acts, there were quantitative differences in their repertories: the relative frequency of behavioral categories ‘‘resting’’ and ‘‘social interactions’’ were higher for I. cuspidata whereas ‘‘reproduction’’ and ‘‘grooming’’ were higher for D. oliverioi. The main qualitative difference between these two species was related to the forms of parental care: females of D. oliverioi guard their eggs and first instar juveniles, whereas females of I. cuspidata scatter their eggs in time and space and do not actively protect their offspring. Since both species share the same habitats (sometimes in multi-species aggregations), the behavioral differences between them may be explained by particular morphological and physiological characteristics of the species, as well as by phylogenetic constraints.