Things have been busy here in Chitengo, and I am struggling to find time to update the blog amidst the preparations to our upcoming biodiversity survey of the Cheringoma Plateau. But I simply cannot resist mentioning one of the most remarkable creatures that I have had the pleasure to meet in Gorongosa. Every biologist has a list of organisms that he or she is particularly keen on seeing at least once in the wild. My list is long, but a few days ago I managed to check off it Manticora, or the Monster Tiger Beetle.

With a name like this one would expect a rather extraordinary beetle, and one would not be disappointed. Named after a mythical beast with the body of a lion, head of a man, and the tail of a scorpion, the real-life Manticora may not be as monstrous, but it is nonetheless a stunning animal. 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 Manticora behaves 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. Interestingly, the beetle, which was a male and thus his mandibles ware particularly large, used its maxillae rather than the mandibles to pick up the leftover bits of prey, a behavior I have not seen before in a beetle.

Manticoras have a bimodal pattern of activity, hunting mostly early in the morning, and then again around sunset and, contrary to a frequently repeated misconception, they are not nocturnal. This is likely because of the competition from other, mostly nocturnal ground beetles (Anthia and Termophilum), which are also common here.

The discovery of Manticora in Gorongosa has also solved a small mystery for me. About a week ago I witnessed a strange sight – a very large antlion of the genus Palpares, an insect the size of a small bird, was slowly disappearing, head first, into a perfectly round hole in the ground. That just did not compute, and I had to see what was causing this behavior. I tried to pull the antlion out and something pulled back. But the mystery animal’s strength was no match for my mighty human strength, and I freed the antlion, but not before catching a glimpse of a large, flat head about the size and shape of a penny, disappearing deep into the perfectly vertical tunnel in the ground. Tiger beetles have larvae that behave in exactly this way, and now I am convinced that I stole the prey from a Manticora larva. Next time I see a similar tunnel I will try to find the larva and photograph it.

 

For an entomologist few pleasures in life are greater than arriving in a new geographic area and being stumped by unfamiliar and mysterious insects, often ones that he/she had never suspected existed. I had a moment like this last night, when I ran across a strange, metallic blue insect, about 25 mm long, walking on the sand in Chitengo. My first thought was that it must be a blattodean, some of which are wingless and have a dark, metallic sheen. But when I picked it up I realized that it was a beetle larva. I knew it because the insect lacked well-developed tarsi or any traces of wings or wing pads, and its antennae consisted of only two articles (although one was exceptionally long). But what family? Ground beetles (Carabidae) often have strange, active larvae that hunt insects in sandy areas, and this was my guess.

Then I happened to look up at the trunk of a nearby tree and saw several dozens of these larvae huddled in a small cavity about 2 m above the ground; the one I found must have fallen off the tree and was trying to find its way back home. I concluded that it couldn’t be a carabid as their larvae are ground-dwelling predators and thus unlikely to (a) live high in the trees and (b) form large aggregations.

A few meters away another tree had a second colony of these insects, but this one was a little older. Although it still had a few larvae moving around, most had already metamorphosed into pupae, which were hanging in grape-like clusters, eerily reminiscent of a scene from the movie “Alien”. There were about 50 of them hanging together, but the tree cavity was very deep and narrow, and I couldn’t get a good photo of the group. I had never seen beetle pupae hanging in a similar formation. The mystery deepened.

I shone a light into the cavity and squeezed my hand in to scoop one of the pupae. At that moment I noticed two adult beetles, which seemed to be guarding the cluster. They were clearly a male and a female since one individual was slightly larger and had distinctly thickened front legs with a pair of large spines; I assumed that it was the male. Both beetles ran away when I put my hand in, but quickly returned and assumed the same position near the clutch of pupae.

And they were darkling beetles, or Tenebrionidae! One of the first things you learn in an entomology class is that tenebrionids have elongate, vermiform larvae that burrow in the ground, and for this reason it never crossed my mind that the blue, free-running larvae in the tree might belong to this family. A cursory search of coleopterological literature revealed that my beetles may be members of a large, nearly cosmopolitan genus Strongylium, of which some species are arboreal. If any any entomologist reading this has another idea, I would love to know it – being stumped by an unknown insect is a pleasure, but never learning its identity is torture.

Update: The identity of this beetle has been revealed to be Pycnocerus sp. (Tenebrionidae: Lagriinae). Thanks to Kip Will and Rolf Albu for this information.