Wikipedia:Reference desk/Archives/Science/2019 February 23

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

February 23

European Stag Beetle Comment

What species of stag beetle is this? I always thought this was a lesser stag beetle. What I call a greater stag beetle is bigger, blacker and has much larger antlers but having looked at images on the internet, it appears some people think this is a greater stag beetle. Is this a juvenile then perhaps? Our articles on stag beetles and Lucanus cervus aren't very helpful. They also say stag beetles emerge May to August and only live a few months; I photographed this one this afternoon, so that's bollocks then, isn't it? Thanks for any help.--Ykraps (talk) 21:42, 23 February 2019 (UTC)

This suggests that it is a greater stag beetle (the wing case colour is apparently diagnostic). Matt Deres (talk) 21:52, 23 February 2019 (UTC) (Nice pic, BTW)

(EC)Thanks and thanks for the link. I always thought that those with very short mandibles were females, so thanks for clearing that up. However this beetle was perhaps 2" long and the greater stag beetles I remember were perhaps twice that big with the antlers making up around 50% of the overall length. So if this is a greater stag beetle, it's quite a small one. Of course, I am assuming there are only two native species; there may well be more.--Ykraps (talk) 22:27, 23 February 2019 (UTC)

Yes. I'm not an entomologist but this confirms your specimen as a male stag beetle (Lucanus cervus), not lesser stag beetle, of which even the male has much smaller jaws. I'm not aware of stag beetles moulting once in their adult form - "juveniles" would be in larval form. As regards the time of emergence, I can only guess that the unseasonally mild weather has confused this individual. PaleCloudedWhite (talk) 22:19, 23 February 2019 (UTC)

Thanks PCW, that certainly does look the same but see my reply above. I think my digging and hacking (not really gardening) disturbed it, or them I should say, as I uncovered three of them.--Ykraps (talk) 22:33, 23 February 2019 (UTC)

I think there are only 2 native UK species referred to as 'stag beetle' - Lucanus cervus (stag beetle - what I assume you mean by 'greater stag beetle'?) and Dorcus parallelipipedus (lesser stag beetle). According to this, the lesser stag beetle reaches about 3cm length and "can be distinguished from the male Stag Beetle by its smaller jaws and distinctively knobbed antennae, and from the small-jawed female Stag Beetle by its all-black wing cases". As regards the size of your specimen, it falls within the 50 - 75mm length given in the link I gave above. PaleCloudedWhite (talk) 23:02, 23 February 2019 (UTC)

I guess the ones I am remembering were 3" (75mm). This picture is more what I imagine when I think of the greater variety.[[1]] Interestingly, the article talks about young beetles.--Ykraps (talk) 23:16, 23 February 2019 (UTC)

I would read "young" beetles in that context to just mean newly emerged adults. I haven't seen any source referring to adults moulting and getting bigger - they do all their growing in the larval stage, which lasts for years. On the timing of sightings, this survey report states that in the UK "adults were seen in all months except November". It also states that the earliest sighting in the year is January, albeit that one was dead. Males also emerge slightly earlier than females. Might be worth reporting your sighting/picture to the survey? PaleCloudedWhite (talk) 08:15, 24 February 2019 (UTC)

Thanks for the latest info. I didn't realise there was a survey. I have reported my findings and uploaded some pictures.--Ykraps (talk) 12:36, 24 February 2019 (UTC)