Sex Role–Dependent Behavioral and Architectural Divergence in a Jumping Spider

Posted by
  Sex Role–Dependent Behavioral and Architectural Divergence in a Jumping Spider ABSTRACT Sex differences in behavior and functional traits are often attributed to differences in mating effort intensity, but the role of sex-specific parental demands remains poorly understood. Using the jumping spider Toxeus maxillosus —where males engage in mate searching and courtship without providing parental care, while females provide extended maternal care from egg attendance to offspring maturity (around 3 months)—we conducted an exploratory investigation into whether these distinct selective pressures led to divergence in spatial behaviors and nest architecture. Results revealed that males and females showed equivalent accuracy, latency, and learning-related performance in both a route-planning test under water stress and a color-pattern associative memory task. In contrast, during nest-construction assays, females built complex, multi-entrance structures that closely matched the container'...

Reproductive phenology of an opilionid species maturing in early summer, Himalphalangium spinulatum, showing evidence of protogyny (Opiliones: Eupnoi: Phalangiidae)

Posted by

 


Reproductive phenology of an opilionid species maturing in early summer, Himalphalangium spinulatum, showing evidence of protogyny (Opiliones: Eupnoi: Phalangiidae)

Abstract

The reproductive phenology of Himalphalangium spinulatum (Roewer, 1911) (Eupnoi: Phalangiidae), which overwinter as juveniles and mature in early summer, was surveyed at a riparian forest on the Sendai River, Tottori City, Honshu, Japan. Females became adults about 3–4 days earlier than males. The body weight of females and males and the number of mature eggs retained in females were highest at the age about a week after the final molting, suggesting a shorter time is needed to commence mating and oviposition in this species. This might be the reason for the shorter time lag in maturation between females and males in this species compared to other species of protogynous harvestmen.

Nobuo Tsurusaki, Minako Kawaguchi, Yamato Funakura, Toru Matsumoto "Reproductive phenology of an opilionid species maturing in early summer, Himalphalangium spinulatum, showing evidence of protogyny (Opiliones: Eupnoi: Phalangiidae)," The Journal of Arachnology, 53(1), 13-19, (19 May 2025)