Some more local Andrena Mining Bees

21st April 2014

I blogged recently about seeing one of the first mining bees to appear in spring; Andrena clarkella. It's lovely; as the season progresses, to now see other species emerging locally and attempting to get some decent photographs.

I've also been enjoying reading a facsimile copy of W. E. Shukard's book, British Bees, published on 1866. I just love the style of writing and thought I'd use some extracts. These are from his "General Observations" of the Andrena bees and gives some very useful descriptions of the genus. Firstly, on nest building and provisioning:

"Varying in the species, some prefer vertical banks, others sloping undulations, and again others horizontal flat ground or hard down-trodden pathways. Some burrow singly, and others are gregarious, collected in great numbers upon one spot. They are, perhaps, the most inartificial burrowers of all the bees. Their tunnels vary from five to nine or ten inches in depth, and in some species they are formed with other small tunnels slanting off from the main cylinder. The sides and bottom are merely smoothed, without either drapery or polish. The little cells thus formed are then supplied with the usual mixture of pollen and honey kneaded together, which in the larger species forms a mass of about the size of a moderate red current, its instinct teaching it the quantity needed for the nurture of the young which shall proceed from the egg that it then deposits upon this collected mass of food. The apertures of each little tunnel is closed with particles of the earth or sand wherein the insect burrows, and it proceeds to the elaboration of another receptacle for a fresh brood until its stock of eggs becomes exhausted.

Some species have two broods hatched in the year, especially the earlier ones, - for several present themselves with the earliest flowers, - but others are restricted to but one. The quantity of pollen they collect is considerable, and in fact they are supplied with an apparatus additional to what is furnished to any of the other genera in a curled rather long lock of hair that emanated from the posterior trochanters. This, with the fringes that edge the lower portion and sides of the metathorax, as well as the usual apparatus upon the posterior legs, enables the insect to carry in each flight home a comparatively large quantity of pollen, but perhaps scarcely enough at once for the nurture of one young one, and it therefore repeats the same operation until sufficient is accumulated."

This next section describes rather elegantly, the variation of appearance amongst members of the Andrena:

"The insects in their perfect state vary very considerable in size , both individually and specifically, the former depending upon both the quantity and quality of the food stored up, for the pollen of different plants varies possibly in its amount of nutriment, else why should we observe so marked a difference in the sizes of individuals whose parent instinct would prompt to furnish them with an uniform and equal supply. The differences of specific appearance is often very considerable in long genera, and perhaps in no genus is it more conspicuously so than in Andrena, for here we have some wholly covered with dense hair, and others almost glabrous; others again with the thorax only pubescent; some are black, some white, some fulvous, or golden tinted, and some red; some we find banded with decumbent down, and others with merely lateral spots of this close hair, but the most prevalent colour is brown, which will sometimes by immaturity take a fulvous or reddish hue."

If you haven't been able to identify the bees (all females) in this post, here's a list of them as illustrated (top to bottom):

- Andrena flavipes;
- Andrena nigroaenea;
- Andrena nitida;
- Andrena cineraria;
- Andrena haemorrhoa.

[Click on any image for a larger version]

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