New insights into maternal care and juvenile dispersal in Pterinopelma roseum (Araneae: Theraphosidae)

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  New insights into maternal care and juvenile dispersal in Pterinopelma roseum (Araneae: Theraphosidae) Abstract Tarantulas (Theraphosidae) exhibit a wide diversity of reproductive behaviors, yet many aspects of their natural history, particularly those related to maternal care and juvenile dispersal, remain poorly known. Pterinopelma roseum is a species distributed in southern Brazil and northeastern Argentina for which information on reproductive biology is limited. The aim of this study was to document maternal care, egg sac composition, and juvenile dispersal through the monitoring of a female collected together with its egg sac in Misiones Province, Argentina. The female was maintained under controlled laboratory conditions and observed daily until juvenile dispersal. During the incubation period, the female actively protected the egg sac, remaining in contact with it most of the time and displaying defensive behaviors when disturbed, while continuing to feed regularly. The e...

Offspring Defensive Investment Covaries With Brood Value in a Female Cobweb Spider

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Offspring Defensive Investment Covaries With Brood Value in a Female Cobweb Spider


ABSTRACT

Maternal investment in offspring defense is expected to enhance offspring survival and parental reproductive success. In cobweb spiders that construct detritus-based, bell-shaped retreats, these structures serve to protect the spiderling. The brood value hypothesis predicts that such defensive investment should be proportional to brood value (e.g., egg sac mass and number). We tested this hypothesis in the cobweb spider Campanicola campanulata by conducting field measurements of retreat architecture and maternal defensive investment in relation to egg sac presence, weight, and total grains. As predicted, females with egg sacs constructed larger retreats, and investment increased with both egg sac mass and egg count. These results support the brood value hypothesis and highlight retreat architecture as a crucial yet understudied component of parental care in spider.

Zhang, H., J. Liu, C. Li, et al. 2026. “ Offspring Defensive Investment Covaries With Brood Value in a Female Cobweb Spider.” Integrative Zoology. https://doi.org/10.1111/1749-4877.70160