Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens

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  Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens Abstract The venom of the slender black scorpion Centruroides nigrescens , from the State of Guerrero México, was fractionated by Sephadex G–50 gel filtration, followed by carboxymethyl cellulose ion separation and high–performance liquid chromatography, permitting to obtain two new peptides toxic to arthropods. The estimate LD 50 of the soluble venom for the insect Acheta domesticus was 11.1 μg/g body weight, and for the arthropod Armadillidium vulgare was 61.1 μg body weight . The amino acid sequence of toxin Cnige1 (toxic to A. domesticus and A. vulgare ) contains 65 amino acids, with a molecular mass of 7273.37 mass units, whereas toxin Cnige2, toxic to A. domesticus , contains 68 amino acids, with a molecular mass of 7548.81 units. Both peptides are well packed, containing 8 cysteines, which in the native venoms are forming 4 disulfide bridges each. The amino acid sequences f...

Male and female crab spiders “cooperate” to mimic a flower

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Male and female crab spiders “cooperate” to mimic a flower

Female crab spiders (Thomisus spp) are able to camouflage themselves as flowers not only to successfully avoid being preyed upon by birds but also to ambush flower-visiting insect prey (Nature 2002; doi.org/10.1038/415133a). This mimicry manipulates flower signals and may vary from species to species. However, do male crab spiders, which are usually much smaller in size and darker in coloration than females, also camouflage themselves in this way?

In a tropical rainforest in Xishuangbanna (Yunnan, China), we observed one male and one female crab spider (Thomisus guangxicus; Thomisidae) in an apparent partnership, to jointly mimic a single Hoya pandurata (Asclepiadaceae) flower. In this image, where the male crab spider lies on the back of the conspecific female, the male appears to mimic a flower's pistils and stamens while the female appears to mimic that same flower's fused corolla. The flower's complex color is matched as a whole only when individual spiders of both sexes are present. This could be an example of “cooperation” that expands the niche of both females and males in mimicry systems, and cooperating individuals may have improved survivorship and predation efficiency. It would also be interesting to investigate the co-evolution between male and female crab spiders.

Wu, M., & Gao, Y. (2024). Male and female crab spiders “cooperate” to mimic a flower. Frontiers in Ecology and the Environment, 22(2), e2721. https://doi.org/10.1002/fee.2721