Structural Organization and Statistical Analysis of Pedipalps in Two Salticid Spider Species: Salticus scenicus and Plexippus petersi

Abstract

This study focuses on jumping spiders of the family Salticidae, specifically Salticus scenicus and  Plexippus petersi, known for their exceptional visual acuity and distinct sexual dimorphism. Males of both species possess modified pedipalps used for sperm transfer, with variations in palpal structure that influence mating. The palpal organ includes the genital bulb, haematodochae, subtegulum, tegulum, and embolus, which differ in complexity between species. The embolus varies in length with longer emboli linked to more intricate palpal structures. Morphometric analysis explored the relationship between pedipalp length and body dimensions (prosoma and opisthosoma). Spiders were collected, fixed, and examined under a microscope. Statistical analysis revealed significant correlations, with notable variation between species. In the Salticus scenicus, the prosomal length was less significant, whereas in the Plexippus petersi, the prosomal length had a highly significant correlation with the pedipalp length.  These findings suggest that larger pedipalps are generally associated with longer body parts, with species-specific constraints at greater pedipalp lengths. The diversity in palpal morphology supports sexual selection and species diversity, contributing to our understanding of taxonomy and phylogeny in salticid spiders.