Nature photographer Piotr Naskrecki, whom we’ve met before, is in Mozambique and, at his website The Smaller Majority, is documenting his adventures. Several days ago he wrote about the larva of the Monster Tiger Beetle (Manticora redux), which led me to his post last month on the adult of the same species. I don’t want to reprise most of what he said about this nasty but amazing piece of work, so go over and read about it yourself.
(Note to pedantic readers and creationists: by “piece of work” I am speaking metaphorically and not implying that there was a creator who designed this beetle! And do I really have to say stuff like this?)
Anyway, here’s the adult nomming a grasshopper: Piotr notes (his words are indented):
It is the world’s largest tiger beetle (Cicindelinae), with a robust, heavily sclerotized body that easily reaches 65 mm in length. Its head, especially that of the male, is equipped with a pair of mandibles that would not look out of place on a stag beetle but, unlike the mostly ritualistic function of large mandibles in stag beetles, those of Maticora are very much functional.
Despite its size Manticorabehaves in a way quite similar to smaller tiger beetle species. Its movements are agile, and it can run like hell and change direction in a split of a second; they cannot fly, however. These beetles hunt anything that moves, although prefer orthopterans, but unlike other tiger beetles it appears that the sense of smell rather than vision is their main tool for locating their victims. Once prey is located the beetle clasps it with its enormous mandibles and literally chops it to pieces. I watched it find and kill a large wolf spider – at first I thought that the spider would put up a fight, but about two seconds later what was left of the spider was a nicely masticated ball of tissue and a small pile of legs. After the main body was consumed the beetle picked the legs, one by one, off the ground and ate them, too.
Apparently the mandibles do double duty (see Piotr’s caption):The larvae are just as nasty:
The larvae of Manticora are similarly carnivorous, but rather than actively pursuing their prey the way their parents do, they are sit-and-wait predators. At that time I had not been able to see or collect Manticora larvae, but tonight I finally managed to snag one.
Like other tiger beetles, the larvae of Manticora hunt from the safety of their narrow, nearly vertical burrows in the sand. Their soft body is safely tucked inside the tunnel, and the only thing that is visible on the surface is a large, heavily sclerotized head and pronotum, both of which form a shield that blocks the access to the burrow. The mandibles of a Manticora larva are pointing upwards so that any insect unlucky enough to step on the head is instantly grabbed by its leg and pulled underground. Imagine walking down the street and stepping on one of those round metal plates that cover sewer manholes, only the plate turns out to be the head of monster, and you are instantly sucked underground – this is what it must feel to a cricket or an antlion as it is being dragged by Manticora.
When Piotr tried to extract one of these from its burrow, he had a tough time, and thereby discovered a cool adaptation:
Eventually, I used the insect’s own voracity to catch it – I gently touched the head with the forceps, and when the mandibles snapped around it I grabbed the head and pulled the larva out. It was not easy as the 5th abdominal tergite of the larva is modified into a large, spiny structure that effectively anchors the animal in its burrow. The larva’s morphology reminded me of marine polychaete worms that use a similar tactic for catching prey from the confines of their burrows.
An unlucky cricket is seized by its leg and dragged underground to its doom:
h/t: Matthew Cobb