From spiderling to senescence: ontogeny of color in the jumping spider,Habronattus pyrrithrix

Abstract

The diverse colors of animals serve a variety of purposes, from acquiring mates to avoiding predators. Often, color patterns are not static throughout life, but change drastically during development, maturity, and senescence. While recent work has focused on the signaling value of vibrant colors in jumping spiders (Salticidae), we know very little about how colors change as spiders age; such information can provide a context for understanding the functions of and constraints on colorful traits. Focusing on Habronattus pyrrithrix Chamberlin 1924, our goals were to examine (1) the microscopic morphology of the colored body regions that males display to females during courtship (i.e., males' red faces, green legs, and white pedipalps), (2) how the colors of these regions as well as dorsal color patterns change during development prior to sexual maturity, and (3) how male condition-dependent red facial and green leg coloration changes as males age beyond sexual maturity. Although the bright white pedipalps and green legs of males appeared only upon sexual maturity, the sexes began to differentiate in facial coloration and dorsal patterning, with males developing red faces and conspicuous black and white dorsal patterning as young juveniles (ca. 2.5 mm in body length, or ca. 45% of their total mature adult body size). Even after maturity, color was not static; a male's green legs (but not red face) faded with age. Results are discussed in the context of potential functions of and constraints on color in salticids, and how they may change throughout an individual's lifetime.