Platycis minutus Net-winged Beetle at Woodbank, Astley Burf
Jane Scott
During 2012 individuals of Platycis minutus a Nationally Notable beetle were seen in Worcestershire and reported in Worcestershire Record in 2012 & 2013. These were all singletons and seen in the north west of the county, three in Wyre Forest area and one at Astley Burf. Rotting beech is frequently mentioned as a favoured wood but birch is also used and we certainly have plenty of this at Woodbank, including quite a lot of fallen timber which we leave in situ to rot down wherever possible.
On 28th August 2014, two beetles, both about 5 mm long were seen at Woodbank, one on nettles and the other showed great interest in the corner of one of our raised beds in the vegetable garden. I had read that this species is known to cluster, so the following day I checked around the nettles and found none but on searching around the raised bed I found seven individuals, one or two noticeably larger at about 8 mms. Some were tucked well down the inner side of the raised bed but others were sitting on top of the edge whilst a couple were found at the top end of longer grass just outside the bed. This corner of the raised bed is by far the most shaded and gets the sun for only a short while at this time of the year. Taking a closer look I found that the wooden boards were showing distinct signs of rot on the inner side at and below soil level and I assume it was this that had attracted them to the spot, although I have no idea what timber was used in the manufacture of the boards. (01, 02).
I continued to check them most days from 25th August until 7th September and they remained in the same spot, either just walking slowly around or resting and showing no sign of aggression if, as occasionally happened, their paths crossed. During this time, on 1st September there was a mated pair confirming my view that the larger ones were female (03). By the 10th there were only two in evidence, both males but we did see what appeared to be a female sitting on the back porch 50 metres away. The following day a male and female were seen at the raised bed, whilst on 12th, only one at the raised bed but another was found by David sitting near the top of our large conifer hedge some 100m away. None were around the original spot on the 13th but we did find a female inside the back porch.
On the 14th September the magnificent seven were all back at the raised bed and this time there was a lot of activity with a female walking around with three or four males on top, (04) one of which appeared to have sustained damage to both the wing and wing case during this encounter. I checked later in the day and the female, still with her entourage attached, had moved to the inside of the boards and appeared to be trying to tuck herself well into the area of the rotting wood. I watched for some time but did not see any evidence of egg laying.
After all the excitement on the 14th no beetles were seen the following day and between the 15th to 27th September the occasional male appeared at the raised bed. This was not always the same individual, as I saw the beetle with the damaged wing case once or twice but at other times there was no evidence of any damage on the individual seen.
Over the five week observation period it was interesting to note they could be seen at anytime from early morning to dusk and, on days when I was able to check, they were in evidence throughout the day rather than just appearing occasionally. The Net-winged Beetles have a reputation for being difficult to find as they have a relatively short season as adults but they are known form clusters and I think I was fortunate to have had the opportunity to view them with relative ease.
References
Bingham, J. 2012. Invertebrate Records from Worcestershire 2012 – Worcestershire Record 33:7-9.
Brown, A. 2013. Coleoptera of note found in the Kidderminster area 2010-2013. – Worcestershire Record 35:25-27.
Brock, P. D. A comprehensive Guide to Insects of Britain & Ireland. Pisces Publications
Watford Coleoptera Group: www.wcg.org.uk.
Images
01. Platycis minutus 11.09.14. Jane Scott.
02. Platycis minutus 31.08.14. Jane Scott.
03. Platycis minutus mating cluster 01.09.14. Jane Scott.
04. Platycis minutus mating cluster 14.09.14. Jane Scott
