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 ...

Out of North Africa: Evolution and biogeography of Afro-Arabian dwarf tarantulas (Theraphosidae, Ischnocolinae)

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Out of North Africa: Evolution and biogeography of Afro-Arabian dwarf tarantulas (Theraphosidae, Ischnocolinae)

Abstract

Large-scale vicariant events are expected to create congruent phylogeographic patterns among unrelated taxa. A continental-wide disjunction displayed by unrelated plant taxa across Afro-Arabia (the RAND flora pattern) has been traditionally explained as a consequence of late Miocene aridification of the region and the formation of the Sahara Desert. We implement genomic data (UCE), divergence time estimation and biogeographic analyses to uncover the origins of RAND pattern distribution in dwarf tarantula genus Ischnocolus Ausserer, 1871. The results suggest that the disjunct distribution of Ischnocolus resulted from ecological vicariance driven by the Middle Miocene climate cooling, predating the timing of the aridification of the region. Our results thus bring evidence of phylogeographic discordance of the RAND pattern origins among different taxa. Conserved lifestyle and the preference for humid environments among the early diverging Ischnocolus lineages also suggest that dispersal across Afro-Arabia was likely catalyzed by interspecific competitive exclusion. Subsequent lifestyle switches, that enabled the dwarf tarantulas to successfully colonize dry environments, evolved repeatedly in the group’s evolution. Additionally, we delimit the boundaries of the genus Ischnocolus and assess its position within the tarantula phylogeny. As a consequence, we revalidate the genus Luphocemus Denis, 1960, which is endemic to North Africa.
Korba, J., & Opatova, V. (2026). Out of North Africa: Evolution and biogeography of Afro-Arabian dwarf tarantulas (Theraphosidae, Ischnocolinae). Molecular Phylogenetics and Evolution, 108559. https://doi.org/10.1016/j.ympev.2026.108559