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Post by nomad on Apr 9, 2017 18:28:33 GMT
I went out today to look for the Black oil beetle Meloe proscarabaeus. A colony occurs in the grassland of the defensive ditch of an Iron Age Hill fort. Although they are quite a large Beetle they are not easy to find in the sward and when disturbed they can move at quite a speed. In Britain this species is usually found in suitable habitats around the coast, so its good to find them at at inland site. The life cycle of these beetles is fascinating. The larvae are parasites of ground-nesting solitary bees. At the end of spring, female oil beetles dig burrows in the ground close to colonies of host bees, into which they lay around 1000 eggs. These eggs usually hatch the following year in order to coincide with the emergence of the bees. The oil beetle larvae 'tringulins' climb up onto flowers where they wait for a host bee. They attach themselves to the bee and they will be flown to the host's burrow, where the tringulin oil beetle turns into a grub-like larva, and develops, feeding upon the pollen stores and eggs of the host. The larva pupates and the resulting adult beetle spends the winter inside the host's burrow before emerging the following spring . All images April 2017.
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Post by nomad on Apr 10, 2017 7:32:00 GMT
* Warning* In spite of the image here showing me holding an Oil beetle on no account should any person pick up a Meloe species or other Blister beetles because when threatened they release oily droplets of hemolymph from their joints ; this contains cantharidin, a poisonous chemical causing blistering of the skin and painful swelling. Although I have handled them before with impunity this time although I did not get any blisters, one of my hands feels like it had been placed in a stinging nettle bush several times and turned Red. So a word of warning watch them from a distance.
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Post by wollastoni on Apr 10, 2017 7:53:15 GMT
Thank you Peter for this article. I ignored everything about the strange lifecycle of this species... and about it being harmful ! Hope your hand will recover soon, that's the joy of field entomology !
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Post by Adam Cotton on Apr 10, 2017 11:23:44 GMT
* Warning* In spite of the image here showing me holding an Oil beetle on no account should any person pick up a Meloe species or other Blister beetles because when threatened they release oily droplets of hemolymph from their joints ; this contains cantharidin, a poisonous chemical causing blistering of the skin and painful swelling. Although I have handled them before with impunity this time although I did not get any blisters, one of my hands feels like it had been placed in a stinging nettle bush several times and turned Red. So a word of warning watch them from a distance. I was wondering whether you had any problems after letting it crawl on your finger. The toxins produced by these beetles are indeed rather dangerous, and the common local species here has bright warning colours as well. Adam.
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Post by nomad on Apr 10, 2017 12:54:08 GMT
I knew previously they had dangerous toxins but did not know how to obtain a better photograph showing the features of this species, having handled them before to no ill effect, however my hand is still red but fine with no blisters, I got off rather lightly but was not so lucky in Corsica,while photographing this species collector-secret.proboards.com/thread/594/blister-beetle-mylabris-variabilis there was several on the same plant, they must have been spraying a chemical because my hands the next day were a mass of blisters, I did not connect it at first to the beetles, I thought it was an allergic reaction to a plant species but without doubt it was the beetles, although I did not handle them, I was very close to them using a macro lens. I went to Corte to a chemist who gave me some cream which did the trick. These beetles can even cause skin-tissue, eye damage. Chemical warfare beetle style.
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