Why do xylocopts dig holes?

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ИНО, 03.08.2015 4:47

On two occasions (23.08.2011 and 09.10.2013), Xylocopa sp.was observed in earthen burrows. (it was not possible to determine up to the species, or X. valga, or X. violacea). What is this, such an unusual nesting option or a winter burrow, like a bumblebee? But all the literary sources I've come across agree that they spend the winter in their nests. I met the explanation of xylocop finds in the ground by the fact that there were supposedly tree roots there, and already nests in them. In my case, this explanation is not appropriate. The first hole, although it was dug in an oak forest, but at a decent distance from the nearest tree and was quite shallow (it was at the beginning of the digging process) - it did not reach the roots:

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The second one is located in a clay slope away from woody vegetation:

picture: ___2_533.jpg

And here is a similar photo from the Macroid: http://macroclub.ru/macroid/show_image.php?imageid=60965

And from another resource (the author is clearly far from entomology, so it makes sense to look only at photos, they do not lie): http://www.putnik.nkorol.ru/franc/page_9.html

Comments

Likes: 1

04.08.2015 18:11, ИНО

Burrows that are very similar to those dug by xylenes, I meet regularly in the same places in autumn and early spring, but I have reliably recorded their builders-only twice. In summer, these burrows are not present, and bees do not wander in those places, but only around dry trunks, buildings and flowers. So the version with wintering looks very convincing (the literature is only against it, but, therefore, it is necessary to edit).

I do not see any fundamental difficulties in checking the fact of xylocop wintering in nests: find a living nest in the summer (making sure that the female provides it), come to it in the winter, cut it down. If there are bees there, then they spend the winter in the nests (at least sometimes), if it is empty, they spend the winter somewhere else (at least sometimes), or the sad option is that someone ate them all during the" fattening up", but this is less likely. But I personally pass here: not only do I not know how to cut (and there is nothing), I have never found a nest. True, I didn't look for it (like the swallowtail caterpillars). But for Hierophis, the task is just right. Correct the authors of the article in the CC with your discovery, isn't it tempting, Roma?

This post was edited by ENO-04.08.2015 18: 13

04.08.2015 18:23, Hierophis

The simplest method is
"It's better to just put tags and dig up when she finishes her business, and then take a picture and catch it."
but the caveat is that such a hole still needs to be found in the fall

This will already 100% prove the fact of xylocop wintering in burrows, it is generally unrealistic to exclude wintering in nests - how many nests need to be gutted so that the data is reliable ))

By the way, there is one more nuance here: it turns out that according to our laws, and even the RF laws, even official scientists are forbidden to conduct research on Red Book animals, you need to take a lot of permits from all sorts of ministries, and for a publication where the facts of killing or destroying nests are mentioned in one way or another, they can then be fined take it off. These are the cases