Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application

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  Spider venom peptides Ht1a and Gg1a are toxic to honeybee parasite Varroa destructor by topical application Abstract Global food supply strongly depends on honeybee pollination services, which are threatened by insecticides and pests such as parasitic Varroa destructor mites. Chemical varroacides/acaricides are hampered by resistance development, necessitating the development of sustainable and environmentally friendly alternatives, with arthropod venom peptides being considered promising sources of acaricidal toxins. With only a few acaricidal venom peptides being reported, we performed a systematic topical screening of 50 arthropod venoms against V. destructor , with 78% of the venoms causing 100% mortality after 24 h. Deconvolution of the venoms from the Tasmanian cave spider Hickmania troglodytes and the Giant Japanese funnel-web spider Gigathele gigas led to identification of the varroacidal peptides Ht1a and Gg1a. Topical application of Ht1a and Gg1a reduced varroa mite ...

Riparian spiders make pyriform silk attachment discs that stick better when wet

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Riparian spiders make pyriform silk attachment discs that stick better when wet

Adhesion in wet conditions presents significant challenges due to the disruptive effects of water on interfacial bonding, spreading, and curing. Many organisms have evolved adhesives that adhere strongly in damp or submerged environments. However, the pyriform silk attachment discs of the western black widow spider lose ∼8x of their adhesive strength when wet. Here, we test the hypothesis that riparian species of spiders have evolved attachment discs that are resistant to water's adverse effects on adhesion. We compare adhesion of attachment discs from three terrestrial, relatively dry habitats to three riparian spider species when discs are loaded under both dry and wet conditions. Failure modes shifted from dragline breakage in dry conditions to adhesive failure in wet conditions across all species, highlighting water's impact on interfacial bonding. However, riparian species attachment discs maintained adhesive force when wet while terrestrial species experienced ∼50% reductions in peak force and work of adhesion in wet conditions. These findings suggest that riparian spider silks have evolved specializations that maintain adhesive performance of pyriform attachment disks in wet environments, offering insights into bioinspired design for water-resistant adhesives.

Bernd F. Steklis, Todd A. Blackledge; Riparian spiders make pyriform silk attachment discs that stick better when wet. J Exp Biol 2025; jeb.250902. doi: https://doi.org/10.1242/jeb.250902