THE USE OF FRUITS BY THE NEOTROPICAL HARVESTMAN NEOSADOCUS VARIABILIS (OPILIONES, LANIATORES, GONYLEPTIDAE)

Abstract

Harvestmen are solitary, nocturnal foragers that have a variety of feeding habits, ranging from scavenging to predation (see review in Gnaspini 1996). Although harvestmen seem to be generalist omnivorous arthropods, accepting both plant and animal matter, several species show a tendency to carnivory (Bris? towe 1949; Capocasale & Bruno-Trezza 1964; Anuradha & Parthasarathy 1976; Gnaspini 1996; Machado et al. 2000). Reports of frugivory in harvestmen are scarce and in gen? eral are restricted to captive animals (Capo? casale & Bruno-Trezza 1964; see also Gnaspini 1996). In this paper we provide the first detailed account of frugivory by a har? vestman species, and investigate if fruit size and chemical content of the fleshy portion can influence fruit use by the harvestmen. The study was conducted from October 1995 to February 1997 in the lowland forest of the Parque Estadual Intervales (24?14,S, 48?04'W), a 490 km2 reserve located in the Ribeira Valley, Sao Paulo state, southeast Bra? zil. The study site (Saibadela Research Sta? tion, elevation 70 m) receives about 4200 mm of rainfall a year, with no month receiving less than 100 mm. Rainfall, however, is less intense and less frequent between April and Au? gust, when the temperature may drop to nearly 10 ?C (mean ? SD = 20.8 ?C ? 2.5 for the study period). This period contrasts with the wetter period (September-March) when tem? peratures may reach 42 ?C (25.7 ?C ? 2.8). The vegetation is predominantly composed of old-growth forest (sensu Clark 1996) with an open understory and trees reaching up to 30