First record of the spider Isigonia limbata Simon, 1897 (Araneae, Anyphaenidae) for Northeast Brazil, with notes on natural history

Abstract

This study presents the first record of the spider Isigonia limbata Simon, 1897 (Araneae, Anyphaenidae) in the state of Ceará, extending the species distribution to the Northeast region of Brazil. The research was conducted in a semideciduous montane forest at Sítio São Luíz, in the municipality of Pacoti, located within the Serra de Baturité Environmental Protection Area (APA). The region is characterized by a high-altitude environment that supports the maintenance of isolated humid forests, forming vegetation enclaves surrounded by the semi-arid Caatinga and serving as important biodiversity refugia. During field expeditions conducted in August 2024 and February 2025, male and female specimens of the species were collected, and behavioral observations provided information on its natural history. The I. limbata female constructs three-dimensional silk retreats on the inferior surface of perforated leaves, using the opening as an ambush point to capture prey on the superior surface. During the reproductive period, the spider seeks out intact leaves and constructs a completely sealed retreat in which the female remains with the eggs until they hatch. The construction of these reinforced, isolated shelters suggests a protective strategy against predators, parasitoids, and microclimatic variations, evidencing parental care behavior. The presence of I. limbata in the Northeast, previously recorded only in dense forest areas such as the Amazon, may reflect climatic events that occurred during the Pleistocene, while also reinforcing the importance of these areas for understanding the distribution of the genus Isigonia Simon, 1897 and revealing new occurrences.