Specialized predator-prey interactions are key to understanding ecological and evolutionary dynamics. We document the predatory behaviour of Vigdisia praesidens, a theridiid spider recently discovered to feed on Nasutitermes canaliculatus termites during nest repair in Marojejy National Park, Madagascar. We induced damage to N. canaliculatus mounds in Analamazaotra National Park, >500 km south of Marojejy, promptly followed by mass arrival of V. praesidens to the nest. Based on direct observations and 800+ photographs and videos, we detail the predatory strategies of Vigdisia. Spiders arrive soon after termite nest disturbance, construct a silken scaffold, then hunt by flicking sticky silk towards termites at cavity edge or by fishing: casting silk into the nest interior. Spiders capture both workers and soldiers, the latter without eliciting defensive response, then haul them to nearby vegetation via the scaffold. Spiders aggressively competed for captured prey, with captors successfully defending their catch. Pheidole spinosa ants successfully stole dead termites temporarily abandoned by Vigdisia, in a three-way species interaction similar to the one documented in Marojejy. Male Vigdisia arrived in abundance to nearby vegetation, presumably seeking mating opportunities, but did not hunt. Our findings extend the known range of V. praesidens, support its specialized predation, and underscore that inducing termite-nest damage may reveal additional spider stenophagy worldwide.
The locomotor system of the group of wandering spiders is well adapted to terrestrial locomotion, namely, to be prepared for both complex manoeuvres and rapid movements. To reveal the secrets of the outstanding manoeuvrability of wandering spiders when compared to other arthropods, their locomotion needs to be studied and analysed. To that end, the walking kinematics of the troglophile huntsman spider of the genus Spariolenus Simon, 1880 (Sparassidae) were analysed from markerless motion capture outputs for the first time. In addition to kinematic data, spatio-temporal measures of walking spiders were analysed. Our study, based on a novel graphical gait-classification approach and a new numerical walking-mode-similarity method, suggests that the manoeuvrability of Spariolenus spiders is ensured by adapting to a metachronal wave mode during slow walking and by altering the swing sequence at higher speeds. The adaptation of wandering spiders to terrestrial locomotion provides a crucial functional blueprint for biomimetic designs. This paper intends to enhance our understanding of the ways spiders and other multi-legged animals walk, as well as to contribute to the design of legged robots that can navigate unstructured terrain. This study provides some lines of evidence for the successful adaptation of Spariolenus species to caves and other subterranean environments, which require special manoeuvring on rocks and in crevices to reach prey and avoid threats.
It is well known that spiders exhibit a broad variety of agonistic behaviours towards their conspecifics during interference competition. However, it remains unclear how much these behaviours shift/alter as a coping mechanism in response to changing abiotic factors such as temperature. Therefore, the present study examined the effects of temperature (20°C, 25°C, 30°C, and 35°C) on different agonistic behaviours between individuals of male jumping spiders (Phidippus regius) during interference competition. It was hypothesized that the frequency of competitive behaviours of P. regius would increase as the temperature increased. The results revealed that the presence of a conspecific had a statistically significant impact on the frequency of all behaviours recorded except resting. The most frequently observed behaviours in the presence of a conspecific comprised leg extensions and palpal drumming. The effects of temperature change were less well defined. All behaviours, except leg extensions, increased in frequency with temperature but the increases were not statistically significant. Statistically significant negative relationships were found between the extension of one or two front legs and temperature. With respect to variability among the spiders tested, coefficients of variation ranged from approximately 30% to 350% across all recorded behaviours. While the results of this study indicate that certain competitive behaviours in male P. regius are influenced by temperature, that the substantial behavioural plasticity observed among individuals suggests that jumping spiders may be well equipped to cope with varying thermal conditions.
Spiders are among the most frequently encountered arthropods in human-built environments, yet fine-scale variation in assemblage structure within and around dwellings remains poorly documented, particularly in tropical regions. Here, we characterise spider assemblages across human-built indoor and outdoor microhabitats in Darién Province, eastern Panama, based on repeated sampling of occupied houses in two rural localities during the dry and rainy seasons. We sampled five predefined microhabitats along an indoor–outdoor gradient and analysed patterns of species richness, abundance and assemblage composition. Our results suggest that spider assemblages are primarily structured by microhabitat type rather than by season. Outdoor and peridomestic microhabitats, particularly gardens, supported higher richness and greater compositional heterogeneity, whereas indoor microhabitats were dominated by a smaller number of taxa. Seasonal effects on assemblage structure were weak, with substantial overlap between dry and rainy season samples. These patterns are consistent with the view that human-built environments function as microhabitat mosaics, where local structural features and microclimatic conditions impose strong ecological filters while partially buffering seasonal variability. Fine-scale sampling in and around dwellings also revealed noteworthy faunistic records, including new country records for Panama. Overall, this study highlights the ecological and faunistic value of indoor–outdoor microhabitat approaches for understanding spider assemblages in tropical human-modified landscapes.
