Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

Posted by
  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

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

Posted by

 


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