Factors affecting lifespan in bird-eating spiders (Arachnida: Mygalomorphae, Theraphosidae) – A multi-species approach

Lifespan is a life-history trait being of utmost importance, as it is frequently closely related to individual fitness. However, interspecific comparisons are relatively rare, being hampered by the high effort to collect longevity data across taxa. We here compiled lifespan data for 85 species of bird-eating spiders (Theraphosidae) held in captivity, based on 2183 individual records from the animal record books of both zoological gardens of Berlin, Germany. Using a data-mining approach we sought for broad patterns of correlations between lifespan and an array of other variables as derived from the literature. We found that the subfamily Eumenophoriinae lived on average longest, followed by the Theraphosinae, Ornithoctinae, Grammostolinae, Selenocosmiinae, Ischnocolinae and finally the Avicularinae. Species inhabiting tropical, more humid and/or low-altitude environments lived longer, suggesting that more predictable environments facilitate the evolution of longer lifespans. Furthermore, large range size, low abundance, sub-terrestrial life-style, and aggressive behavior were all associated with longer lifespans. Evidence for resource allocation trade-offs was revealed as larger spiderling and prosoma size was negatively related to longevity. Our rather rough approach revealed several patterns worth of future investigations, and illustrate the value of zoo records for interspecific comparisons.