Urokodia sheds light on the origin of chelicerae and book gills of Chelicerata

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  Urokodia sheds light on the origin of chelicerae and book gills of Chelicerata Abstract Chelicerates are a diverse group of terrestrial and aquatic arthropods, yet their origin and early evolution remain debated 1 , 2 , 3 , 4 , 5 , 6 . Among different hypotheses 7 , 8 , 9 , 10 , 11 , one proposes that the front appendages, known as chelicerae, of chelicerates evolved from the short great appendages (SGAs) of Cambrian megacheirans 12 , 13 , 14 , 15 , 16 and that book gills originated from their trunk limbs 7 . Although taxa such as Mollisonia plenovenatrix 7 and Megachelicerax cousteaui 16 provide important clues to the early evolution of chelicerates, the morphological transition from megacheiran-like appendages to true chelicerae and book gills remains unresolved. Here we use X-ray microtomography to reveal the three-dimensional anatomy of Urokodia aequalis , an early Cambrian euarthropod from the Chengjiang biota of China. Urokodia has a seven-segmented head with a scleroti...

Efficacy of neem oil (Azadirachta indica) as an antiparasitic treatment for scorpions (Androctonus bicolor) and its impact on venom production

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By Guy Haimovitch - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=630184

Efficacy of neem oil (Azadirachta indica) as an antiparasitic treatment for scorpions (Androctonus bicolor) and its impact on venom production

Abstract

Mite infestations are a recurrent welfare issue that significantly affect the health, venom production, and survival of scorpions, particularly under human care. Chemical acaricides such as permethrins and fipronil, widely used in veterinary medicine for mite and tick control, are contraindicated in scorpions. Since mites and scorpions both belong to the class Arachnida, even minimal exposure can result in severe toxicity or death. Neem oil (Azadirachta indica) has been widely recognized for its acaricidal, antibacterial, and antifungal properties. Its main compound, azadirachtin, interferes with mite development and reproduction, leading to reduced infestations and egg viability. This study evaluated the efficacy and safety of a 1% neem oil spray for controlling Pimeliaphilus spp. mites in forty adult Androctonus bicolor (A. bicolor) maintained for venom production. Neem oil was applied every 72 h for five sessions. Mite counts, egg viability, clinical tolerance, and venom productivity were assessed. Mite loads decreased progressively, reaching complete elimination by the fifth treatment, with no new mites detected during the subsequent 60 days. No mortality, irritation, or cuticular lesions were observed. Post-treatment venom extraction at six weeks, based on pooled venom, showed increases of 10% in liquid volume, 50% in dry mass, and 36.5% in protein concentration compared with pre-treatment values. These results demonstrate that 1% neem oil provides an effective, safe, sustainable and low-cost acaricidal option for scorpions under human care, with benefits for venom yield and animal welfare.
Planas, J., Moraleda-Berral, P., Checa, R., Mundanatt, V., Zahra, F., Salah, M., Bande, B., Sonavane, M., & Siyam, M. (2026). Efficacy of neem oil (Azadirachta indica) as an antiparasitic treatment for scorpions (Androctonus bicolor) and its impact on venom production. Veterinary Parasitology, 344, 110748. https://doi.org/10.1016/j.vetpar.2026.110748