A venomous beetle — Onychocerus albitarsis

Many beetles have toxins or poisons that they use to defend themselves.  For example, I have posted about blister beetles before.  However, despite the fact that some beetles can spray these toxins on potential predators, they are not considered venomous because they lack a means of injecting their toxin.  Venomous animals, such as some snakes, scorpions, and spiders, have a mechanism that allows them to inject the venom, be it fangs or a stinger.  In wasps, the stinger is a modified ovipositor (which means only female wasps can sting you).

For this reason, I am very excited to share this news with you…scientists have just discovered a venomous beetle!  Isn’t that exciting!?

This particular beetle is a member of the family Cerambycidae (more info: Shiny Cerambycid, Asian Long-horned beetle).  The members of this family are plant-eaters, so the venom this beetle can inject is purely for defensive purposes.

Figure 1 from Berkov et al 2007

Figure 1 from Berkov et al 2007

Perhaps the most interesting part of this story is that the beetle injects its venom using its antenna.  The cerambycids are known for their exceptionally long antenna; indeed the antenna are longer than the body in this family, it is one of their diagnostic characters.  This exciting paper reports: “No cerambycid has previously been reported to use any specialized structure to inject chemicals.” (Berkov et al 2007)

Figure 2 from Berkov et al 2007, the authors are comparing the antennae of the beetle to the stinger of a scorpion.  They are remarkably similar!

Figure 2 from Berkov et al 2007, the authors are comparing the antennae of the venomous beetle (b, e, h) to the stinger of a scorpion (a, d, g).  They are remarkably similar!  Pictures c, f, and i show the antennae of a congeneric beetle to our venomous friend, which lacks both the venom and the adaptations for delivering it.

Happily for curious and touchy humans, the sting of this beetle results in mild inflammation!

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11 thoughts on “A venomous beetle — Onychocerus albitarsis

  1. Pingback: Two cool Kenyan long horned beetles | standingoutinmyfield

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