Structural complexity and prey availability shape spider communities under retention forestry

Posted by
 Abstract Retention forestry is promoted as a conservation-oriented management strategy to sustain forest biodiversity by preserving key structural elements, such as single old trees and deadwood. However, the effectiveness of this approach in conserving the diversity of spiders as generalist predators remains unclear, particularly because the effect of structural elements under retention forestry on spiders may be mediated by its effect on prey availability. We sampled spiders (Araneae) and potential prey (Diptera, Hemiptera, Collembola) in 55 1-hectare plots across mixed temperate forests of the Black Forest, Germany. We used pitfall traps targeting species active on the forest floor. We studied spider abundance, taxonomic diversity, ecological diversity (combined measure of functional and phylogenetic distance) and community composition along gradients of forest structure (canopy cover, proportion of conifers, stand structural complexity, volume of lying deadwood, herb cover and...

Insights Into Spatial Orientation and Cognition in Tarantulas (Araneae: Theraphosidae) Under Natural Conditions, With Notes on Possible Ontogenetic Niche Shifts

Posted by

 


Insights Into Spatial Orientation and Cognition in Tarantulas (Araneae: Theraphosidae) Under Natural Conditions, With Notes on Possible Ontogenetic Niche Shifts

ABSTRACT

Research on cognition in spiders, particularly in relation to navigation, has primarily focused on araneomorphs studied under controlled conditions. Mygalomorphs, such as tarantulas (Theraphosidae), have been largely neglected and almost nothing is known about their cognitive foraging behaviour in natural environments. Here, we present nine observations of arboreal and fossorial New World tarantulas, including a blind cave-dwelling species, which together provide rare field-based evidence that tarantulas may be capable of flexible, experience-based navigation. All observed arboreal species, as well as two fossorial species, exhibited behaviour that may reflect spatial learning, by foraging in prey-rich locations situated relatively far from their retreats. This behaviour differs from ontogenetic shifts in habitat use, which are noted here in several species for comparison; possible ontogenetic shifts in foraging behaviour in troglobitic tarantulas are also briefly discussed. The remaining observations involve tarantulas responding to disturbance with fast, direct returns to their burrows without disorientation. We discuss the likely allothetic and idiothetic cues underlying these behaviours, while also considering alternative or complementary explanations for retreat recognition and foraging movements based on chemical and chemo-tactile cues. Finally, we briefly review existing experimental research on tarantula cognition, as well as studies on physiological and behavioural changes associated with stress or altered internal states that may interact with cognitive processes.

Zamani, A., & West, R. C. (2026). Insights Into Spatial Orientation and Cognition in Tarantulas (Araneae: Theraphosidae) Under Natural Conditions, With Notes on Possible Ontogenetic Niche Shifts. Ecology and Evolution, 16(4), e73329. https://doi.org/10.1002/ece3.73329