Vespa

A couple of weeks ago I posted a few photos of a Hornet Hoverfly and talked a little about the European Hornet she was attempting to impersonate. Today I'm able to bring you the subject of that impersonation, because when I went out on an invert hunt late this afternoon there were several Hornets nectaring on the abundant ivy overhanging a nearby garden wall.

Because of the time of year, and the fact that they didn't look especially big to my naked eye, my first thought was that these were newly emerged males. But all the individuals I photographed had twelve antennal segments and six abdominal, which makes them female: males have one extra segment in both the antenna and the abdomen. I don't know the reason for the difference in abdominal structure, but the antennae are essentially organs of smell, so perhaps having longer ones helps the males to perform their one and only task, which is finding a newly emerged queen and impregnating her, before she seeks out a shelter in which she can hibernate through the winter.

Having established that this is a female Hornet, I started to try to puzzle out whether she might be a queen or a worker. Not that it matters, obviously, but this is the kind of thing I like to waste spend my time on, when I'd be more usefully employed doing housework or gardening (or - to be honest - pretty much anything else). Hornets are primarily carnivorous, catching and killing other insects, but Steven Falk states that the new season's males and queens are especially fond of ivy, while Wikipedia states that workers foraging for the colony change the food they collect seasonally. So, no real clue there. 

In the end I was reduced to walking along our ivy hedge measuring the size of the flower heads - yes, really - and I established that the central head in each cluster tends to be between 3.5 and 4cm in diameter, while the outer ones are usually 2.5 to 3cm across. Then I went back to the uncropped version of this image, which shows that this was a central head, and therefore most probably over 3.5cm across. You'll be disappointed, I know, that I didn't go back to my neighbour's wall to track down the exact head and measure it accurately with a caliper, but you have to draw the line somewhere, and what I got from my highly unscientific research was that this individual, stretched out rather than curved around the top of the flower head, was in all probability more than 3cm long. So, more likely a new queen than a worker. Maybe.

Instead of wittering on about measurements and likelihoods, I could just have left the commentary to a young chap said who stopped to see what I was photographing. "Wow!" he said. "That's massive! I wouldn't like to be stung by that!" No indeed. Luckily though, European Hornets are notably placid unless you threaten them or their nests, and this one and her sisters were all far too busy gorging on ivy nectar to have any interest in humans.