Wild Bees, Wasps and Ants and Other Stinging Insects

by Edward Saunders

OSMIA AND ITS HABITS

I have tried as much as possible to avoid scientific names, but the misfortune is that there are hardly any popular names in use which can be attached for certain to any particular species, and unless this can be done it is of no use using vague names like the "Carpenter Bee", the "Mason Bee", etc. There are many carpenter bees and many mason bees, and though their habits may be alike in this one particular they differ among themselves in the way they use their tools, and it is necessary to know which one we are talking about. It is a common thing to hear people inveighing against Latin names, etc., but they forget that there are no English ones in use, and what is more important, that Greek and Latin names are common property to all nations, so that we can all know what we are talking about, whereas if we call an insect by an English name and the Russians

call it by a Russian name, the difficulty of coming to a mutual understanding is very great. This is only an aside to justify the use of classical names. I quite feel that for popular use in this country a good series of English names might be useful, but we have not got one, and it would require a great deal of care and thought to frame a nomenclature which would really be useable by the persons who require it.

I have made these remarks here because Osmia is a genus whose members vary very much in their habits, and some species of which, like sensible beings, adapt their habits to their surroundings, so that no name such as carpenter bee, etc., would apply to all the species, or, as a rule, even to one. Osmia rufa especially adopts several methods of nesting. This little bee is clothed more or less all over with yellowish hairs; it is compact in shape like all the other species of Osmia, and like them collects its pollen on the underside of the body. It may sometimes be seen flying up and down the walls of a house looking for a crevice to build in, but it is not the least particular as to where to form its cells. In one memorable case the female selected a flute

which had been left in a garden-arbour. The bee constructed fourteen cells in the tube of the instrument, commencing its first cell a quarter of an inch below the mouthhole. The flute is preserved in the Natural History Museum at South Kensington. At other times this species burrows in the ground, at others it makes its cells in crevices of old walls; it has been known to build in a lock, and is said sometimes to inhabit snail shells. Other species of Osmia almost always burrow in banks, but in no case does a habit seem to be uniformly adopted by a species. One well known and rare species, Osmia leucomelana, is a regular bramble-stick species, tunnelling down the pith in the centre of the stalks, but I once found it to my surprise in fair numbers nesting in a sandy bank. Other species again, as a rule, select snail shells to build in; they find an old disused shell lying about in some sheltered place and adapt it to their purposes, commencing their cells singly in the narrow whorls of the shell and side by side as they approach its mouth, i.e. if the shell be a wide-mouthed one like the common garden snail (Helix aspersa). F. Smith, who gives a very interesting account of these

creatures in his Catalogue of British Hymenoptera in the British Museum, mentions a case where the bee finding the larger whorls of the shell too wide constructed two cells across the whorl. Another very interesting case given by Smith is of a nest of many cells of the rare Osmia inermis (which in his days was known as Osmia parietina). A slab of stone, 10 inches by 6, was brought to him with 230 cocoons of this Osmia attached to its under side; when found in the month of November, 1849, about a third of them were empty; in March of the following year a few males made their appearance and shortly afterwards a few females, and they continued to come out at intervals till the end of June, at which time he had 35 cocoons still unopened; in 1851 some more emerged, and he opened one or two of the closed ones and found that they still contained living larvæ; he closed them up again, and in April, 1852, examined them and found the larvæ still alive; at the end of May they changed to pupæ and appeared as perfect insects, the result being that some of the specimens were at least three years before reaching maturity.

There is a nest of yet another style adopted by one of our species (Osmia xanthomelana). This is formed of a series of pitcher-shaped cells made of mud, constructed at the roots of grass. The species which makes it is rare and seems to have its headquarters on the coasts of Wales, although it has occurred in the Isle of Wight and elsewhere. This species also is not constant in its habits, as it has been known to make its cells underground. A very curious habit was noticed some years ago by Mr. Vincent R. Perkins in another species of this genus (Osmia bicolor; [pl. D], 28); the species nests in the ground or in snail shells, but, in the case under his observation, Mr. Perkins found that the little bees covered up all the snail shells in which they had built their cells with short pieces of "bents" so as to make a little hillock over each about two or three inches in height, somewhat resembling a miniature nest of Formica rufa, the large horse ant, each mound containing hundreds of pieces. This is the only record I know of this habit, which must entail a large amount of labour for the bee.

These varying habits in the same species

show pretty clearly that these little creatures are not driven by any blind instinct in the adoption of their methods of nest building: they appear to have a distinct power of choice and adaptation according to their environment, unless of course it can be shown that the offspring of, say, a snail shell inhabitant follows its parents' habits, and that that of a ground borer does the same—but even that would not explain the case given by F. Smith, and quoted above, where an Osmia had filled up the whorls of a shell and then, finding the final whorl too large, placed two cells horizontally to fill it: that seems to indicate distinct design on the part of the bee and would be hard to explain as due to instinct. Unfortunately, with the exception of a very few, the species of Osmia are rare in this country, so that few opportunities are available for studying their habits, which are certainly amongst the most interesting of any genus.

24. Anthophora pilipes, male. 25. Anthophora pilipes, female. 26. Melecta armata, female. 27. Anthidium manicatum, female. 28. Osmia bicolor, female. 29. Bombus terrestris, female. 30. Bombus lapidarius. female. 31. Psithyrus rupestris, female.

[face p. 61.