Pauline

[millerd]

Fascinating close-ups Pauline. While we're still admiring this year's butterflies, there are next year's already in waiting. Amazing. I also note the photo of the pernicious parasite - one annoyingly came home with me on my recent visit to Noar Hill, and waited 36 hours before creeping off my clothes and tucking in...

Dave

[Pauline]

Cheers Dave - I am finding these immature stages very interesting. Trouble is, what I am seeing raises a variety of questions that I just can't answer. Now I know there are a lot of really smart individuals on this site so I have been trying to pluck up the courage to ask, as the answers may well be obvious, leaving me embarrassed. The first question I have concerns the 2 BH eggs that were in the process of hatching late in the day. I wished I could have stayed to determine exactly when these eggs hatched but when I left it was cold and cloudy (as it had been for most of the afternoon). Whether they hatched during the evening or overnight I am still intrigued as to where they got the energy. They are such tiny little creatures and given that butterflies are inactive in cold periods how does that work? Whilst it may well be a good survival strategy (fewer birds around at night and other predatory insects inactive) I am still puzzling over this.

[Pauline]

Well, that question must have either been really daft or very difficult

I'm feeling quite confused and bewildered - which seems to be almost normal for me these days. I'm trying to remember when I last reared Whites. Some might remember better than me as all my rearing activities are documented in my diary - I believe it was when I bought the plants from the garden centre to 'save' the eggs!!! There were an awful lot of them (like about 100) and I remember releasing about 10 butterflies daily into the garden. Naturally, not all the butterflies emerged from the pupa. When this happens I usually just clean out the rearing cage but this time I didn't (sheer laziness!!). I just left it in a corner of the garden and the only thing that has been in it all Winter is the Puss Moth larva that I am hoping might emerge some time soon. It was for that reason I checked it today and found another 4 Whites had emerged . I am now about to plough through my diary to find out exactly how long ago that was but I certainly won't be in a hurry to dispose of any pupa that don't hatch in the future.

[MikeOxon]

I liked your close-up of the wing scales on one of your Whites. I wonder if the patterns are like fingerprints and could form unique identifiers for each butterfly?

I mentioned once before that the 'whiteness' of the upper wings, which causes problems for photographers, is remarkable and has been investigated as a mechanism for improving the efficiency of solar cells. Intuitively, one might think that the wings should be dark, to absorb heat, but, without a circulation system, it would be difficult to convey that heat to the flight muscles, where it is needed. By making the wings super-reflective, the butterfly can position its wings to reflect the heat onto its body, where it is needed.

Which brings us to the question in your earlier post. The primary source of energy for the hatchling lies in the foodstuffs contained in the egg. It would appear that a higher temperature might speed up the chemical reactions needed to exploit this energy source but everything is relative. After all, many fish thrive well in very cold waters. This isn't an expert option but a reminder that nature can operate successfully in an extraordinarily wide range of conditions, while many processes have an optimum temperature at which to operate.

[Wurzel]

Cracking close up of the Large White Pauline It's crazy to see that two coloured scales can have such an effect

Have a goodun

Wurzel

[bugboy]

Someone else on here reared some Large White where a small proportion decided to pass through the winter rather than emerge with the rest. I can't remember who it was but I think it was reported sometime last spring. It would seem a simple case of not putting all your eggs in one basket kind off scenario, keep a few back in case the main late summer brood fails for whatever reason. Off course I say a 'simple case' but if people like you don't rear them in captivity then we'd be very unlikely to know these details. Just goes to show that even with the most common species there are still things to learn.

[CallumMac]

It would seem a simple case of not putting all your eggs in one basket kind off scenario, keep a few back in case the main late summer brood fails for whatever reason.

Of course that doesn't quite work when you think about this behaviour in terms of natural selection acting at the level of the individual (i.e. the caterpillar) - each caterpillar has to 'decide' (except it's probably not a conscious decision) what to do, and the mother can't say 'a quarter of my eggs will pass the winter this year'. I imagine that each caterpillar can decide whether to emerge with the rest - a very safe strategy, but one that means it will be exposed to loads of competition for resources from the others in its cohort - or to pass the winter - a very risky strategy, but one that pays off (if successful) with much-reduced competition. When a caterpillar tries the overwintering strategy and it pays off, its offspring might be predisposed to also try that strategy. By this means the overwintering strategy will pay off just often enough for some individuals in the population to continue to try it.

The observant amongst you will notice that what I've described is exactly the same as the trade-off that maintains long-distance dispersive types in butterfly populations, when dispersing away from your natal patch of host-plant is extremely risky and carries no guarantee of ever finding another patch - but if you are the first individual of your species to find a new patch of host-plant you are laughing!

Whether they hatched during the evening or overnight I am still intrigued as to where they got the energy. They are such tiny little creatures and given that butterflies are inactive in cold periods how does that work?

I always thought that butterfly adults were inactive in cold periods, because they need a lot of warmth to get their flight muscles going. If you're ever emptied a moth-trap the following morning, you'll have noticed the moths sit and vibrate their wings hard for a few seconds (or even up to a minute) before flying off, which I believe is for the same purpose - generating metabolic heat to transfer to the flight muscles. That might mean that the thermal threshold needed by the immature stages to become active might be far lower. One of the metrics that we often use to estimate, effectively, 'available development time' for Lepidopteran larvae is 'growing degree days' which counts degrees celsius per day above a lower threshold - which we usually set as low as 5 degC. Setting it higher (even at 10 degC) means that some of the earliest spring moths appear to have emerged after zero development time (which is obviously incorrect!).

[Vince Massimo]

The first question I have concerns the 2 BH eggs that were in the process of hatching late in the day. I wished I could have stayed to determine exactly when these eggs hatched but when I left it was cold and cloudy (as it had been for most of the afternoon). Whether they hatched during the evening or overnight I am still intrigued as to where they got the energy. They are such tiny little creatures and given that butterflies are inactive in cold periods how does that work? Whilst it may well be a good survival strategy (fewer birds around at night and other predatory insects inactive) I am still puzzling over this.

Hi Pauline, a few general thoughts on the subject from me also.
Firstly, I have observed several species of larvae (and seen reports of many more) that are active at temperatures well below the threshold where adults are able to fly. When monitoring overwintering Red Admiral eggs and larvae in 2017/2018 I found that larvae emerged from eggs in November, December, January and February. I also noted that the smaller the larva, the better it seems to be able to cope with cool weather (just don't ask me why).

Brown Hairstreak egg shells are noted for being particularly tough and it is well documented that the larva can take a whole day to chew a hole large enough in the shell to be able to emerge. However, like everything else, they will have their limits and it is possible that they will stop such activity when the temperature gets too low. In March this year I observed a Red Admiral larva take approximately 8 days to emerge from its egg from the time that it started to eat through the eggshell. For most of this period the top of the egg was open, but the temperature was too low for any activity.

You may not yet have caught up with the Red Admiral observations topic after your winter break but you can find it here: viewtopic.php?f=8&t=9581#p126253 . It contains a lot of interesting data.

Vince

[Pauline]

Cheers Mike Now there's another good question - fingerprints eh?! Reckon it would take a dedicated photographer and a hell of a computer program to check that one out Mind you, for all I know it may already have been done!!!!........and your proposal makes perfect sense to me.

Isn't it just Wurzel! 2 more emerged today btw

I seem to recall that too Paul but can't remember who either. That seems like a reasonable survival strategy to me but I wonder if many other species do it.

Hi Callum - good to hear from you and thank you for taking the time to provide such a detailed explanation. I think that Bugboy was implying the same as you ie, it is not the butterfly's choice but the caterpillar, (although the phrase he used might have been misleading) but in any event it could well be in the interests of the species for the reasons you have outlined .Forgive me if I should already know this Callum - you may have explained earlier - but given the scientific nature of your response I am intrigued to know what your involvement is in this subject matter? The great thing about this site is that there is so much expertise and experience there is always someone who can answer your queries no matter how bizarre they may seem

Thank you too Vince. I know from experience of rearing BH that the eggs can easily take 3-4 hours to hatch but I didn't know whether they would continue once it got colder. When I returned the next morning I didn't know whether they would still be hatching and was a little surprised that it was all over and no larva to be seen. What you've stated is really interesting and I'll definitely make time soon to look at that topic.

[Pauline]

My visit this morning to Botany Bay was all I would have wishes. Perfect weather, great company and lots of butterflies. The Wood Whites were already active when we arrived but provided enough photo opportunities as they battled with a strong breeze. About a dozen seen in the usual spot:

another fingerprint

Perhaps the best sighting, one which I certainly haven't seen before, was Millerd!!!!! Great to meet you at last Dave. Dave and I had been chatting for some time about everything butterfly related when of course the subject came round to Holly Blues. We hadn't seen one at all during the day and I suggested to Dave that perhaps he should have brought a handful with him. I had no sooner got the words out of my mouth than a Holly Blue flew past and landed at Dave's feet??? Honestly, what's the chance of that happening?????

It was time to leave but on the way back we stopped to take a shot of this lovely moth that flew towards us:

[Goldie M]

Hi! Pauline, if you've got any Small Whites we could do with some in the North, I've seen only one this year and none in the Garden so far which is unusual. Goldie Just seen your Wood White Shots lovely Pauline

[CallumMac]

I think that Bugboy was implying the same as you ie, it is not the butterfly's choice but the caterpillar.

Yes - sorry, in hindsight it does sound like I was contradicting him, but I didn't mean to be! I agree that we were largely saying the same thing, but I just wanted to clarify that the 'decision', such as it is, is taken by individual caterpillars rather than as a collective.

No reason for you to know this as I'm still very new on here, but yes, I'm a postdoctoral researcher at York University, in the research group of Jane Hill and Chris Thomas. I'm currently studying how butterfly and moth phenologies have been changing over the last 40 or so years of climate change. However I count myself very lucky to have landed in this field as I've been a butterfly and moth recorder and photographer for much longer than I've been a scientist!

[Andrew555]

Nice Beetles Pauline, I like watching the Tigers too.

Love your Large Whites and Wood Whites, and brilliant crisp images that bring them to life.

[bugboy]

If many more pictures of Dave appear on here we might have to set up a species specific page for him too

I think that Bugboy was implying the same as you ie, it is not the butterfly's choice but the caterpillar.

Yes - sorry, in hindsight it does sound like I was contradicting him, but I didn't mean to be! I agree that we were largely saying the same thing, but I just wanted to clarify that the 'decision', such as it is, is taken by individual caterpillars rather than as a collective.

No offense taken , you just filled in some of the science details behind my very basic conclusion.

[Pauline]

Cheers Goldie - if I see any Small White's I'll definitely point them in your direction. My latest 2 captive Large Whites to emerge were much smaller than any I've seen so I wonder whether it was to do with their prolonged development period?

Wow! That must be a dream job Callum. Thank you again for responding to my question

Thank you for the compliment Andrew. It's fair to say that Buggy's diary had a significant influence on my interest in beetles - I only like the pretty ones mind

If many more pictures of Dave appear on here we might have to set up a species specific page for him too

If many more pictures of Dave appear on here we might have to set up a species specific page for him too

It's not often that I manage to get out twice in one day but early evening I decided to check on immatures on Noar Hill. The first butterfly I spotted was a Dingy Skipper. I took this shot simple because it was the first one I've seen this season and I certainly can't compete with Mark's lovely images.

and with Wurzel in mind, this was the best I could do without lying on the ground, which, given the number of ticks I've had so far already this year, is no longer an option:

I was disappointed not to be able to find the Green Hairstreak egg as I had guessed it may just have hatched. I then discovered 2 of the batches of Duke eggs I had previously found were also gone . Despite finding a fresh batch of Duke eggs I felt things weren't going too well.

However, things were beginning to look up when I saw 2 female Holly Blues egg-laying. Perhaps a bit of Dave's magic had rubbed off on me Pity I don't have his skills in photographing these lovely little butterflies but this was the best I could do on a near vertical slope!

I stood for some time watching a pair of Brimstones as I felt sure their activities would result in a coupling - but again no luck. At this point I decided to cut my losses and go home but before leaving I decided to have quick look for those BH larva. Bingo!!!! I immediately found one of them and not many leaves away from where I lost him I am hopeful the other is still there too but I wanted to keep disturbance to a minimum. So here we have a wild BH which I believe is now days old.

After this great success I renewed my efforts to look for eggs and found several more which I believe are Holly Blue given that she was laying in this area. However, I didn't actually see her lay these ones so I suppose they could be Green Hairstreak?

Just before I left the site another small butterfly literally flew into me - another first for the season, a Small Heath:

[Goldie M]

Hi! Pauline, your certainly making up for lost time at the beginning of the Season
I seem to be missing butterflies at present
I went to GB yesterday and inspite of lovely Sunshine nothing appeared, one of those days I think Goldie

[Neil Freeman]

Dave and I had been chatting for some time about everything butterfly related when of course the subject came round to Holly Blues. We hadn't seen one at all during the day and I suggested to Dave that perhaps he should have brought a handful with him. I had no sooner got the words out of my mouth than a Holly Blue flew past and landed at Dave's feet??? Honestly, what's the chance of that happening?????

It must have been in his pocket, either that or witchcraft...there is no other answer

I have just seen the moth on Dave's diary too...it is a female Muslin Moth.

Cheers,

Neil.

[Wurzel]

Lovely hairy Small Heath Pauline, like a little Teddy Bear I liked your stained glass shot, sterling effort but my favourite shots is of The Holly Blue Whisperer in full on whisper mode

Have a goodun

Wurzel

[David M]

I love your 'fingerprints', Pauline. It's so interesting to see the fine detail of a butterfly's wings in such a way. Of course, seeing Wood Whites at all in the UK is a joy in itself so I'm sure you had a satisfying time.

I think your moth may be diaphora mendica - muslin moth. I've seen a few of these on the Gower and they're rather striking, aren't they?

[millerd]

In answer to the egg question... Hmm, not sure, but they look more Holly Blueish to me. The trouble is eggs of both change colour a bit as time passes, so that guess is exactly that. I've been trying to find dogwood with both types of egg on the same bud cluster, but haven't succeeded despite seeing both species apparently laying in the same areas on dogwood at Denbies and over at Mill Hill.

That is a nice Small Heath close-up too - they really are furry little creatures.

Dave