Saturday, 30 June 2018

Caterpillar crazy

Caterpillar breeding has reached unprecedented levels of care and volume here, and in the various foster-families who are kindly rearing infants from eggs laid by moths which visited my trap earlier in the year. After four seasons of Emperor Moth breeding, which I much enjoyed, I managed to find homes for all the brood hatched this Summer, and they are causing much interest and excitement. 

The plump ones in my first two pictures, shown with their foster-Mum's finger for a handy size comparison, are the subject of much youthful inquiry, both at home and in the local primary school. The family reported earlier this week: 

The caterpillars have been fine and are enormous! They are scoffing piles of hawthorn and seem equally happy with brambles. They had a trip out on Tuesday to see the class I am volunteering with. By a stroke of luck they were doing insect life cycles and they were really interested. Some good questions came up, such as: do the different thicknesses of stripe denote male and female? And: why don’t they get prickled on the thorns because they have soft bodies? Do they shed their skins as well? I thought I had killed them the day after you left when there was this shrivelled skin but there were still six alive and well so I imagine that’s what it was.

Excellent questions and ones to which I am not certain of the answer, apart from the skin-shedding which is another fascinating fact for children. Imagine if we burst out of our skins every so often, emerging in brand-new shiny and sometimes differently-coloured shape (as with the Emperor larvae which start off black and end up green). If anyone reading this can help, my friends and the school would be delighted. Meanwhile, a further bulletin arrived last night:

It’s all been happening today! First thing I thought one of them was poorly as it seemed to have a bit of an upset tummy. So I isolated it with just hawthorn, in case it had overdone it on the brambles. Now it looks perkier and seems to have sorted itself out digestive-wise. Plus! A different one seems to be pupating! I put some dry grass and leaves in and moved them all to a larger container and one has fine webby stuff round it as though it is the beginnings of a cocoon. I assume that I clean the rest out as normal but leave that corner alone. I am probably more excited than I ought to be and was quite upset this morning. I do hope this isn’t addictive...

I am afraid that it is. Meanwhile, the grandchildren's White Ermines have been astonishing their keepers by the enormous amounts of dandelion they are eating and by the results at the other end - if not having breakfast, see picture above. They have looked after them so successfully that over 50 are thriving and we have re-adopted two-thirds of them to help out. You probably thought like me that the dandelion was a common plant, too common indeed. But they are getting scarce in part of Walthamstow. See why, below:

Finally, the Bedford family in Oxford, who have another branch of the Emperor family, are kindly offering me eggs of an Eyed Hawk which was found mating with its partner by a colleague of Tom B. I'm hoping to sort out a pick-up this weekend; and so the saga will go on. It brings back memories of my own excitement when my brother and I bred Elephant Hawks successfully as children (and had the same heart-stopping moment when I first saw their shed, shrivelled skins). And if any of this year's keepers can be present when the moths eventually emerge from their pupae, that is an unforgettable sight. Partly for its strangeness and beauty and partly, as my granddaughter observes with great emphasis after seeing a hatch at the Natural History Museum in Kensington: "Grandpa, do you know? The FIRST thing it did was a huge WEE!"

Back in the garden, I have lit the trap for the first time since we got home from holiday. Showing signs of my age, I went outside an hour or so later when the grandchildren and their Mum and Dad arrived for the weekend, and was startled by the fact that our climbing roses seemed to be glowing. I actually got as far as getting the iPad and taking a photo before realising that the eerie and rather lovely effect was caused by my sighting of the trap right behind the wall. There it is, above.

There were some nice moths inside, including the Swallowtail above - in good condition for a large and fragile moth which often gets a battering and tattering early in its short life, judging by the condition of many of those which come to my light.  Below we have a Buff Ermine and a handsome example of the darkest version of that very variable moth, the Common Rustic.

Finally, another favourite: the small (observe my ubiquitous thumb comparator) but very attractive micro Anania coronata.


AlexW said...

Caterpillars typically don't show sexually dimorphic colors or structures. Stripes may possibly be influenced by health and environmental conditions; even though I am not familiar with your UK entofauna, it seems safe to assume that both sexes are externally indistinguishable

As for the thorns, I presume that the animals simply walk around them. From your pics, it appears that the plant has large and widely-spaced thorns designed mostly for vertebrate deterrence.

side note: I have also seen cats, aphids, an small heteropteran bugs happily bumbling about on plants w sticky gnatkilling trichomes (petunia?) or dense microthorns (tomato). Interestingly, the long stilty legs of the aphid and hetero seem to help them lift their bodies over the spiny parts.

You may wish to browse Google Scholar for detailed discussion of such herbivore-plant arms races


Martin Wainwright said...

Thanks very much Alex - that's all most helpful and I'll pass it straight on

all warm wishes


Vikki Rose said...

Hi Martin,

I wonder if what your granddaughter saw wasn't the butterfly having a wee but dispelling Meconium (red liquid substance used to inflate the wings & then dispelled before first flight)? Our Emperors have also pupated so the long wait begins :-)

Warmest wishes,