Admiral question

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  • #58566

    LeslieD
    Participant

    I have a caterpillar castle full of nettles and admiral caterpillars. So far I’ve released 5 and they have all been red admirals. What puzzles me is some of the caterpillars are brown and some are black. I thought until now maybe the black ones were the juvenile caterpillars, this based on seeing some brown ones pupating. But right now I’ve got about 4 little black ones pupating. Are they a different critter? AND anyone know how to tell male and female admirals?

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  • #58581

    Terry
    Participant

    Wellington, Very windy due to it’s position at the south of the north island! I had heard it was still a good source of U Ferox compared to other areas where it gets cleared due to its nasty sting! As I was saying in my previous reply the conditions in NZ are very different to the UK. In Wellington your longest day 21 December is 15.09 hrs and the shortest 21 June 9.11 hrs. Where I am in South East England the Longest day 21 June is 16.35 hrs and shortest 21 December is only 7.52 hrs hence the extra struggle to keep Yellow Admirals through the winter period. Our weather can get hotter in the summer than where you are, but the winters are much colder. I visited New Zealand back in the early 1990s in January and was surprised that it was dark so early in mid summer as I was used to it still being light an hour later midsummer in the UK.

    #58580

    LeslieD
    Participant

    I’m in Karori which is a high suburb of Wellington. Very rare to get a frost here and equally rare to get very hot weather, although where I got the nettles does get light frosts sometimes. There is a lot of ferox there on the farm in Makara which is on the south coast but I’ve found the common nettle from there to be a great source of eggs/caterpillars and a whole lot easier to live with as well.
    We get a lot of yellows where I am but not many reds so I’m hoping they will establish.

    thanks for your reply, they are fascinating little creatures.

    #58579

    Terry
    Participant

    The eggs and larvae just take longer to develop if laid on nettles followed by cooler weather conditions. Obviously those laid on nettles in a spot where the sun gets at them for longer periods of the day will speed development. Digging up the plants and placing them anywhere warmer will have the same effect.

    In NZ conditions are different from the UK and our winter period is longer and much colder than yours with shorter winter days due to latitude, hemisphere, etc (see comparisons on the time and date website for precise details), so there will be variations in development for many differing reasons.

    If we compare your Red Admiral with ours there are some major differences. Our Red Admiral, V atalanta has habits more akin to the Yellow Admiral in that it is a butterfly of more open sunny habitats (and it migrates) whereas your Red Admiral V gonerilla is more often found in forested areas and its favorite food plant U ferox is often found (but not always) with some tree cover. I do realize both Yellow and Red Admirals can often be seen together but there are nonetheless differences. As for egg survival in the shade, well in summer no problem, but in the winter frost penetration can kill the eggs but very small larvae will make a tent and because they are (in a manner) undercover they can survive harder frosts. Low temperatures for long periods can also be a factor in losses. One sharp frost may see the small larvae survive but a long period of frosts with no daytime thaw could see a higher rate of losses.

    In the UK Yellow Admirals would never make it through the winter in the wild, the days are too short and the temperatures much lower for long periods of time. The odd v atalanta larvae and butterfly make it through a mild UK winter in warmer spots and along coastlines where frost does not penetrate but we rely on migrations from southern Europe and North Africa each year for the main crop!

    Out of interest which part of New Zealand do you live in?

    #58569

    LeslieD
    Participant

    Thanks Terry … fascinating. Some of the nettles I’ve lifted from the original spot on the farm have been kept in the shade as spares. Do the eggs ‘hibernate’ in the shade? the caterpillars keep coming when put in the sunny enclosure .. i thought I would have run out of caterpillars by now but not so. Maybe the caterpillars were already there as very tiny when I shifted the plant into the sun. Whatever the case I have five tiny new pupas 🙂

    #58568

    Terry
    Participant

    They do naturally differ in colour however you may have some Yellow Admiral larvae mixed in with your Reds. That said, with both species in NZ and including our Red Admiral vanessa atalanta in the UK, the colours can develop depending on light levels at the location of the foodplant. Looking for v atalanta tents on nettles in the summer in the UK will show greenish light versions in nettle patches in bright sunlight and darker colours in nettle patches in more semi shaded areas. (v atalanta doesn’t oviposit on nettles in shade unless they receive long periods of sunshine during daylight hours). Hence no butterfly breeder worth his salt would bother looking for v atalanta larvae in dark woodland nettle patches. As for my captive Yellow Admirals the larvae I produce indoors from collected eggs are all dark shades and those (in high summer only) left in the butterfly house can be of the grey to green variety but the darker colours tend to dominate!

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