Holly blue caterpillar feeding behaviour

[Padfield]

Yesterday, I found three holly blue caterpillars on ivy in the garden, one during the day and two after dark. The one I found during the day (early 4th instar I think) spent the day moving round his ivy crown, nibbling a hole in one bud after another, and by this morning he had moved to a nearby ivy crown and continued doing the same thing (if some pictures on this page don't load, reload the whole page):



The 2nd instar caterpillar found last night had remained in the same place:



The last one, a late 4th instar I think, was on the move when I found him this morning (all pictures by flash, as he is in a shady part of the garden):






(he changed his mind about going that way)









He didn't like that flowerhead, however, so went back and moved onto another, smaller but with fresh, young buds, where he then stayed:



His complete journey, over about half an hour:



His final resting place was very close to the 2nd instar caterpillar:



The characteristic, nibbled buds are a good indicator of holly blue caterpillar presence, but as the caterpillars move so readily, and evidently some distance, it's not quite the same thing as following purple emperor caterpillars!

Guy

[Pete Eeles]

Great work, Guy! The only individuals that I've tracked have simply moved to the underside of a nearby leaf to moult.

Cheers,

- Pete

[Padfield]

Thanks Pete. My lot move all the time, seeking out the unopened buds.

The one I thought was 2nd instar now looks like third instar - it's very difficult to get good photos deep in the shade. If so he moulted last night, and very quickly, whether or not he moved off to a leaf in the meantime. He was on a different ivy crown this morning:



The white line seems better defined and he seems less of a hippy.

Yesterday, for comparison:



And a shot of the first one I found, perfectly camouflaged on an ivy crown some distance from where I originally spotted him:



Guy

[Padfield]

The larger 4th instar larva had disappeared by today. Last night, under UVA, he was a dull, matt violet colour, unlike all the other cats, which show up rather bright white-green. I suspect he was undergoing pigment changes inside and preparing for pupation (according to Pete's book, there is a colour change before pupation). Today I searched all nearby ivy crowns and there was no hint of him - so I guess he has gone wandering in preparation for pupation.

After dark I found another freshly moulted 4th instar cat - very small but velvety green and without a white stripe:



I'm a complete beginner on holly blue instars, and Pete might correct me. If I've got them right, it's because his book is a good teacher!

Of the four caterpillars I've found in the last three days, three have been low down on this ivy bush, covered in flowers and in a shady part of the garden:



There are probably many more higher up, where I can't examine the flowers. I haven't found any cats or signs of feeding on ivy flowers in direct sun.

Guy