Medical Research Council - London Institute of Medical Sciences

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More species of South American Lonomia caterpillars identified as venomous and potentially deadly

30 March 2023


From flashing eyespots to irritating hairs, the defences butterflies, moths and their caterpillars use to protect themselves from predators don’t typically cause us serious harm. Among the few exceptions are caterpillars in the South American genus Lonomia. Usually encountered when resting in groups, these caterpillars’ spines release a potent haemotoxic venom, like that of vipers and rattlesnakes, which can cause internal bleeding and disrupt blood coagulation, sometimes fatally. So far, envenomations have been linked to only two species, Lonomia obliqua and L. achelous, but identifying them can be tricky, and two others (L. orientoandensis, pictured left, and L. casanarensis, right) are known to cause similar reactions in rats. A recent field and taxonomic study identified 60 Lonomia species, seven of which are likely to cause severe symptoms. The only currently available antivenom, directed against L. obliqua, is broadly effective, yet recognising this greater diversity could help further improve treatments.

Written by Emmanuelle Briolat

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