杏吧原创

I found this insect (Photo, top right), and others like it, in my friend鈥檚 home near Stamford, Lincolnshire, in eastern England. It looks as if it is covered in sand but this is clearly a form of camouflage. Interestingly, there were no obvious sand deposits nearby. What is it? And why does it look like this?

The photograph is of a larva of the true bug Reduvius personatus. Although many insects are referred to as bugs, only the insects in the order are true bugs. This particular species is noted for its habit, while in its larval form, of coating itself with dust and any other debris that it can find as a means of camouflage. This activity begins as soon as the larva emerges from its egg and repeats every time the larval skin is shed as the insect grows 鈥� five time in total. The adult does not cover itself with dust, but is dark brown and fully winged.

The insect is associated with mammal habitats, especially those of humans, where it is active mainly by night and so generally escapes notice. It is a predator that feeds on other invertebrates, such as silverfish, by grabbing them with its legs and inserting its mouthparts into their bodies to relieve them of their nutritious innards. The mouthparts of true bugs consist of a tube-like instrument, the rostrum, which is one of the features that distinguish them from beetles, with which they are sometimes confused.

R. personatus is found across Europe and also in North America, where its camouflage technique has earned it the common name, 鈥渕asked bug鈥� or 鈥渕asked bedbug hunter鈥�. In the UK it is sometimes known as the 鈥渇lybug鈥�. The flybug is not as common as it once was and perhaps this reflects the decline in abundance of a favourite prey species 鈥� the bedbug Cimex lectularius. Recently, however, populations of C. lectularius seem to be increasing so it is possible that the flybug may yet make a comeback in the UK.

Ray Barnett Bristol, UK

Thanks to S酶ren Tolsgaard, a curator at the for this photo (bottom right) of a camouflage-free adult R. personatus 鈥� Ed