Usually when we consider insects that play a role in the food chain, we think of herbivorous insects, which eat plants and pass the nutrients along to insect-hunting birds, amphibians, reptiles, bats, and other vertebrates. But mantids and other insect-hunting insects are generally larger than the insects they hunt and provide a bigger meal for an insect-hunting vertebrate. Many birds, especially, hunt insects during breeding season because of their high protein content.
As with many other species, the young are particularly vulnerable to predation. Mortality is high among immature mantids, as their bodies become food for a wide variety of predators. Jumping spiders, for example, patrol the same plant stems that young mantids walk around on, and they won’t hesitate to pounce on young mantids small enough to subdue.
Mantids can hear the high-frequency sounds emitted by bats, and if a mantid is flying, it will alter its flight in response. This is a sign that bats may be a primary predator of night-flying mantids.
Mantids aren’t the only species where the male is sometimes eaten by the female. In many spiders, the female may eat her much smaller mate. And in a more general way, in many animals, males that share in the rearing of offspring — establishing and defending a territory that supplies sufficient food, constructing nests, protecting or incubating eggs, gathering food, feeding the young, caring for the mother — are spending a significant amount of their lives in order to ensure their reproductive success.
What’s up with their eyes? There’s usually a dark spot on the eyes of mantids (and several other insects with compound eyes), and that dark spot always seems to be facing you, no matter what angle you view them from. How does this work? It’s caused by the structure of their compound eyes — essentially, a result of tubes, shadows, and mirrors. To understand this, imagine a model: Think of their globe-shaped compound eyes as a cluster of narrow tubes, all pointing outward from a center point, and imagine these tubes are coated with silver on the inside surfaces. Closest to you, the tubes are pointed directly at you, and you can see into the whole long (dark) tunnel, while the tubes increasingly angled away from you appear light-colored, reflecting the light.
Taxonomically, mantids (order Mantodea) are most closely related to roaches and termites (order Blattodea); they are in the same superorder (Dictyoptera). In the past, mantids, roaches, termites, and stick insects (such as walkingsticks) were all grouped together with the grasshoppers, crickets, and katydids in the order Orthoptera.