248 FLEAS, FLUKES AND CUCKOOS 



{Furnarius rufus) in South America, harbour related species of bugs. 

 The majority of other bugs (Hemiptera) are plant suckers, but they are to 

 a certain extent preadapted to an ecto-parasitic mode of life, as they are 

 flattened dorso-ventrally and have piercing mouth-parts. Many free 

 phytophagous bugs show a tendency to winglessness, and in some 

 species one sex has wings and the other has not (p. 52). Some 

 of the assassin bugs (Reduviidae) which normally prey on other 

 insects, have become voracious blood suckers and are often found in 

 birds' nests in America. Only one family, the species of which live 

 on bats, have evolved into true permanent obligate ecto-parasites. 



An Anthocorid bug, Lyctocoris campestris, is a cosmopolitan species 

 also found in house-martins' nests in Britain. It is a predator which 

 sucks mites and the pupae of fleas but since it has also been known to 

 feed on human blood its activities in the nest are not beyond suspicion. 

 It probably competes with the pseudoscorpions — arthropods looking 

 like miniature crayfish — which hunt and eat mites. One in particular, 

 Chelifer cancroides, is a constant species in the nests of swallows and 

 martins. It is a great hitch-hiker (see p. 18) and is carried to new 

 feeding grounds attached to various insects, especially flies, which it 

 clasps firmly with its huge pincer-like claws. 



Swallows, house-martins, and also house-sparrows and to a lesser 

 degree flycatchers, which in Britain nest so frequently on man-made 

 buildings, often harbour certain nidicoles for which they and their 

 human neighbours can blame one another. Thus five indigenous 

 species of dermestid beetles are found in their nests and except for 

 Dermestes murinus, which is common in the habitations of various birds 

 of prey, these are only rarely recorded from other wild birds' nests in 

 Britain. Both larva and adult of D. lardarius and D. murinus feed on 

 stored products such as dried and smoked fish and meat, cheese, dried 

 milk, bones, dried insects and so forth. To a certain extent D. lardarius 

 is predacious and if present in large numbers occasionally attacks and 

 kills nestling birds. It has been known to bore into the wing bones of 

 young pigeons and eat them alive. In nests these beetles also feed on 

 dried insect remains, which seem to be a favourite food, for in nature 

 dermestids are also found commonly in wasps' and bees' nests and 

 caterpillar webs. Attagenus pellio, another dermestid found in the same 

 birds' nests as the previous species, feeds on nectar as an adult, 

 but the larva favours a diet of feathers, dead insects, furs, skins, 

 woollen carpets, grain and cereal products. These beetles are scarcely 



