41. Bee fungus.
As in the higher animals, bees are afflicted with parasitic worms which induce disease and sometimes death. The well-known hair worm, Gordius, is an insect parasite. The adult form is about the size of a slender knitting needle, and is seen in moist soil and in pools. It lays, according to Dr. Leidy, "millions of eggs connected together in long cords." The microscopical, tadpole-shaped young penetrate into the bodies of insects frequenting damp localities. Fairly ensconced within the body of their unsuspecting host, they luxuriate on its fatty tissues, and pass through their metamorphoses into the adult form, when they desert their living house and take to the water to lay their eggs. In Europe, Siebold has described Gordius subbifurcus, which infests the drones of the Honey bee, and also other insects. Professor Siebold has also described Mermis albicans, which is a similar kind of hair worm, from two to five inches long, and whitish in color. This worm is also found, strangely enough, only in the drones, though it is the workers which frequent watery places to appease their thirst.
Thousands of insects are carried off yearly by parasitic fungi. The ravages of the Muscardine, caused by a minute fungus (Botrytris Bassiana), have threatened the extinction of silk culture in Europe, and the still more formidable disease called pebrine is thought to be of vegetable origin. Dr. Leidy mentions a fungus which must annually carry off myriads of the Seventeen Year Locust. A somewhat similar fungus, Mucor mellitophorus (Fig. 41), infests bees, filling the stomach with microscopical colorless spores, so as greatly to weaken the insect.
As there is a probability that many insects, parasites on the wild bees, may sooner or later afflict the Honey bee, and also to illustrate farther the complex nature of insect parasitism, we will for a moment look at some other bee parasites.
Pl. 1
PARASITES OF BEES.
Among the numerous insects preying in some way upon the Humble bee are to be found other species of bees and moths, flies and beetles. Insect parasites often imitate their host: Apathus (Plate I, Fig. 1, A. Ashtoni) can scarcely be distinguished from its host, and yet it lives cuckoo-like in the cells of the Humble bee, though we know not yet how injurious it really is. Then there are Conops and Volucella, the former of which lives like Tachina and Phora within the bee's body, while the latter devours the brood. The young (Plate I, Figs. 5, 5a) of another fly allied to Anthomyia, of which the Onion fly (Fig. 42) is an example, is also not unfrequently met with. A small beetle (Plate 1. Fig. 4, Antherophagus ochraceus) is a common inmate of Humble bees' nests, and probably feeds upon the wax and pollen. We have also found several larvæ (Fig. 43) of a beetle of which we do not know the adult form. Of similar habits is probably a small moth (Nephopteryx Edmandsii, Plate I, Figs. 2; 2a, larva; Fig. 2b, chrysalis, or pupa) which undoubtedly feeds upon the waxen walls of the bee cells, and thus, like the attacks of the common bee moth (Galleria cereana, whose habits are so well known as not to detain us, must prove very prejudicial to the well being of the colony. This moth is in turn infested by an Ichneumon fly (Microgaster nephoptericis, Plate I, Figs. 3, 3a) which must prove quite destructive.
42. Onion Fly and Maggot. 43. Larva of Beetle.