We know praying mantises are carnivorous – they’ve been documented consuming frogs, lizards, and snakes. But they also kill and consume small birds like hummingbirds, according to new research from zoologists in Switzerland and the United States. We expect birds to eat insects, not the other way around, so the reversal is startling – and humans may have had a role to play in the deaths of these hummingbirds.
The zoologists gathered 147 cases of mantids capturing small birds. Praying mantises from 12 species and nine genera engaged in the behavior, which was found on every continent except Antarctica, in 13 countries. The insects weren’t too picky about the birds they ate either – 24 different species and 14 families of birds were among the prey.
But 70 percent of the cases in this research occurred in the United States. There, the insects have been employed as pest control – a practice which had unintended consequences. Several alien species of big praying mantises were released in North America decades ago for pest control, and now threaten small birds. They snare hummingbirds at hummingbird feeders, or in home gardens filled with plants the birds pollinate. These hummingbirds comprise the majority of the birds preyed upon by praying mantises.
78 percent of the birds captured were eaten, according to the researchers. 18 percent were liberated by humans. Only two percent escaped on their own.
Scientist Martin Nyffeler of the University of Basel said in a statement, “Our study shows the threat mantises pose to some bird populations. Thus, great caution is advised when releasing mantises for pest control.”