Praying mantises are among the most frightening insects on the planet, equipped with powerful front legs which they use to snatch unwary insects, spiders, and even the odd amphibian or reptile. But as new research reveals, praying mantises are also proficient at capturing birds — which they do more often than we thought.
A praying mantis making a meal of an unfortunate Ruby-throated Hummingbird (Image: "What's That Bug?", Randy Anderson/University of Basel).
New research published in The Wilson Journal of Ornithology shows that small birds often fall victim to praying mantises, and that this behaviour exists among many different mantis species around the world. Most cases of this insect-on-bird violence were documented in North America, where small birds — particularly hummingbirds — are snatched by the predatory insects when visiting feeders or house gardens.
Praying mantises have those iconic raptorial front legs which allow them to capture animals and grasp them during a meal. Their primary prey consists of bugs and spiders, but they have also been observed to eat small vertebrates such as frogs, lizards, salamanders and snakes. More infrequently, praying mantises have also been seen munching on the odd bird, but it wasn't known if these were isolated incidents, or a hunting behaviour specific to a select group of praying mantises. The new study, co-authored by James Van Remsen from Louisiana State University and Martin Nyffeler from the University of Basel, now shows that this bird-eating behaviour exists worldwide among praying mantises and that it's definitely a thing that praying mantises do.
The zoologists collected and documented nearly 150 cases of bird-eating mantises from around the world. Praying mantises from 12 different species and nine families were observed to eat small birds in the wild. The researchers documented this behaviour in 13 different countries, and on all continents except Antarctica. Mantises consume a wide variety of birds, including 24 different species and 14 families.
"The fact that eating of birds is so widespread in praying mantises, both taxonomically as well as geographically speaking, is a spectacular discovery," noted Nyffeler in a press release.
Of the birds captured, around 78 per cent were killed and eaten by the mantises, and two per cent managed to escape on their own. The remaining 18 per cent were rescued by humans who couldn't stand to see a bird being torn to shreds by the ravenous insect.
Of the observed cases, 70 per cent were reported in the United States, where praying mantises lie in wait around hummingbird feeders or plants pollinated by hummingbirds in house gardens. And indeed, hummingbirds are a frequent victim of mantises — the Ruby-throated hummingbird in particular.
This finding is troubling given that several alien species of praying mantises were deliberately released in North America a few years back as a pest control measure. These imported insects represent a new threat to hummingbirds and other small birds. This is compounded by the fact that large native mantises also prey on birds. "Therefore, we suggest caution in use of large-sized mantids, particularly non-native mantids, in gardens for insect pest control," conclude the authors in their study.