Purple Hairstreak

[jenks]

Made a trip to Lydford old railway (Lydford Gorge ) on Saturday, 19 June. Saw at least 8 Heath Fritillaries, 6 Small Pearl-bordered Frits, 2 Small Tortoiseshell, 2 Peacock, 4 Small White, 1 Comma, 6+ Meadow Brown, Speckled Wood in numbers (at least 50) AND I disturbed a small purple butterfly in low vegetation which flew up into the nearby Oaks and rested on a leaf showing its silvery underwings. I spent some 10 minutes watching it through my bins. A male Purple Hairstreak. Yes I know its early but a 100% definite sighting. Maybe it was scouting for the main arrivals !

Returning back to Wales, stopped at Collard Hill and saw 6 Large Blue, 6 Marbled White, to add to the days list.

[padfield]

Purple hairstreaks pupate on the tree but soon fall to the ground and spend most of their pupation time in the leaf litter or other vegetation. Probably, your male had just recently emerged from his chrysalis.

I found one in a fuschia one year, underneath a spreading oak in my garden. It must have dropped off the tree and landed in a flower pot. It was absolutely pristine - unfortunately I only had a video camera with me to get a picture:



They don't look like that for long!

It soon zoomed up into the oak.

Guy

[Philzoid]

I would say that this year has been an excellent year for getting good sightings of purple hairstreak. On Sunday at Bookham common there were numerous examples of males and females, some well worn, nectaring on bramble. Perhaps the warm dry summer is bringing them down from the trees? Later on I found a one nectaring on thistle alongside common blues; small coppers and gatekeepers. Although warm the sky was overcast to start so the butterflies were not too active. Good weather for photography (although as you'll see from the images, my camera is not up to the job)

[Felix]

Purple hairstreaks pupate on the tree but soon fall to the ground

That's interesting Guy; in my experience with these butterflies the larvae have always left the tree and pupated in the litter below. In captivity also the larvae have made a very determined effort to leave their sleeves in order to vacate the tree.

There is I believe also evidence to suggest that attendant ants may also carry the final instar larvae from the tree with pupation following within the ant's nest.

In your observations have you seen the larvae pupating in the tree?

Felix.

[padfield]

No - I'm just repeating book knowledge, Felix - I've never bred butterflies (and the nature of oak trees is that it is far harder to find wild caterpillars than, say, white-letter hairstreaks in elms). The old orthodoxy was certainly what I described, but I note (having just checked up) that Jeremy Thomas doesn't accept it and I've got no evidence of my own beyond the occasional discovery of very fresh purple hairstreaks in anomalous places, like our fuschia pots, as mentioned above. In fact, most of my other ground sightings of very fresh individuals could equally be explained by ground level pupation, whether attended by ants or not.

The iPhone butterfly application (not Adrian Riley's - the other one) repeats the old orthodoxy.

My only other relevant observation is that female purple hairstreaks do typically come down low to lay. I had assumed this was so the pupae did not drop out of the canopy but it could also be so they can reach the ground or be reached by ants.

Guy

[Felix]

I remember, around two decades ago decade ago now, I first bred this species and had a massive home made sleeve that enveloped an entire large branch of an old oak tree. This was the first time that I noticed that something was 'up', and was the stimulus for further observation.

The larvae, upon reaching maturity began making their way from the terminal twigs, down the larger 'branchlets' and eventually along the main branch. In the end they congregated en masse where the huge sleeve was tied about the main branch because they were not able to proceed any further. Here they pupated, all massed in the folds of the netting. It was this observation that first got me thinking about the species pupation requirements.

The other observation that I made about this time was the predisposition of this species to cannibalism; the most vulnerable time being when the larvae entered the prepupal stage that lasts for 24 hours or so. Having noticed this I conducted a morbid experiment and discovered that when presented with a choice, younger larvae appeared to actively seek out and devour these prepupae, even when presented with abundant quantities of fresh food plant. I imagine that a prepupa is highly nutritious and represents an opportunity to ingest an equivalent of many hours leaf munching in just a minute or so. This is pure speculation of course...

Felix.

[padfield]

In the heat of the afternoon today I sat on a rock on a hillside, drinking beer and watching purple hairstreaks. Some were zooming around agitatedly, some were chasing up to the tops of trees, but quite a lot of females were coming down low to eye-level branches and just crawling around in the shade of the leaves, either laying or checking out where to lay. It is surely relevant to Felix's observations (above) that the females do tend to come low when they get broody.

I was mostly content to sit and watch from a distance, but couldn't resist the temptation to photograph a few. This female was particularly interested in sniffing around buds and probing them with her proboscis. She seemed to me not to be ready to lay yet (not fat enough yet!) but I think she had prams and nappies in mind:



I think this is the same female...



... but this is definitely a different one, also working her way from bud to bud:



This one was much fresher and perhaps not yet preggers:



I could easily have photographed a dozen females doing this sort of thing, if it hadn't been quite so comfy on my rock.

I had actually gone to see if I could find some July male brown hairstreaks but I don't think I saw any. At these sites, oak grows among sloe, or vice versa, and the purple hairstreaks get everywhere, so you need a good sighting to be sure a random hairstreak bursting out of the blackthorn isn't just a large purple one. Here is a purple hairstreak on sloe:



There were mating grasshoppers on my rock. Amazing camouflage!!





Guy