Invasive species aren’t usually friendly: they outcompete native animals for food, or introduce new diseases into the areas they colonize. It would be challenging, however, to think of a more horrific impact than that of the invasive praying mantis species Miomantis caffra on the local mantises in New Zealand. The invasive mantis, M. caffra, is wiping out the locals via sexual cannibalism.
M. caffra arrived in New Zealand from its native South Africa in 1978. About a decade later, however, things began to really get kinky, in a bad way. Researchers noticed that M. caffra was dominating New Zealand’s sole local species, the appropriately named Orthodera novaezealandiae. Wherever M. caffra turned up, the New Zealand mantis soon disappeared.
“Perhaps the most insidious influence that the invasive M. caffra might have on native O. novaezealandiae populations is through the predation of males mistakenly attracted to the aggressive female M. caffra,” researchers write in the journal Biology Letters.
To figure out whether this was indeed the case, the researchers reared insects of both species in the lab. They exposed males and females of both species to one another, and observed what happened. As it turned out, native males were more attracted to the chemical cues given off by the invasive females than to those of their own species’ females. Nearly 70 percent of love-blinded males that were lured towards the invasive females were then eaten by the object of their desire.
This is not to say that New Zealand females are all that nicer, however. Almost 40 percent of the males who pursued females of their own species were eaten, though at least those sorry wooers may have successfully passed on their genes before becoming dinner.
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