Admirals in Northland

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  • #57794

    nigelrc
    Participant

    I live in Whangarei and am interested in trying to discover what species of native butterfly other than the monarch might have populations in Northland.

    I have regularly attracted Yellow Admirals to my town garden by growing a small plot of the European nettle. However I’m very keen to be involved in any research on the Red Admiral and to hear from anyone who knows whether these species might have breeding populations in Northland. I have twice observed a Red Admiral in Northland, a few years ago now…

    Observations and comments welcome…

Viewing 9 replies - 1 through 9 (of 9 total)
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  • #57839

    Terry
    Participant

    I have tried to bring through larvae of Vanessa itea on pellitory, Parietaria officinalis and Parietaria judaica in the UK but although the Females lay eggs on it and the small larvae will eat it, after a few instars the larvae will either die or look for nettle to eat. Baby’s tears (Soleirolia) is also closely related but I have never tried to feed larvae on it. I would expect to have the same result as with pellitory. It is noted that in Australia Vanessa itea larvae have been found on pellitory, Parietaria judaica and Parietaria debilis so either they can get through in the higher temperatures in Australia on these plants or maybe there is a subspecies of vanessa itea in the hotter parts of Australia. The European Red Admiral vanessa atalanta larvae thrive on pellitory, Parietaria species, and in North Africa and southern Europe where nettles don’t grow or are rare it is its main foodplant.

    #57835

    nigelrc
    Participant

    Good to have the bigger picture & general advice from Norm Twigge. I see the odd Yellow Admiral butterfly in my garden between spring & autumn but have not consistently had them breeding on my Urtica dioica – & I’ve never seen a Red Admiral locally. Yellow Admirals did breed continuously on patches of nettles (U. dioica) in a relative’s garden near Russell & in one or two years the mid winter population of caterpillars was so numerous that they nearly stripped all the foodplants. The timing of the breeding cycle might be important – I guess a good population of caterpillars will have fewer parasites to contend with in winter…? I plan to try planting some Urtica ferox in suitable spots in a patch of covenanted native bush owned by relatives on the outskirts of Whangarei. I’m also encouraged to try & protect or cover at least some larvae if / when I next see them appear on my home-grown nettles.

    One further point of interest… Last autumn I observed what looked to be a freshly hatched Yellow Admiral settling on a patch of baby’s tears (Soleirolia) of which I have plenty in shady patches of the garden. The imago looked as though it was laying, but on close inspection I could find no sign of eggs. Although the plant is a member of the nettle family, I’m not aware that Admirals are able to breed successfully on it.

    Any update on the success of the Honshu White Admiral project in the Waikato?

    #57832

    NormTwigge
    Participant

    As with the majority of the worlds animal species which are in decline, and even extinction due to human habitation, New Zealand butterflies also are threatened with various problems. Given that a butterfly can find its preferred foodplant on which to oviposit, the egg then becomes food for ants and other insects. Upon emerging, the hatchling then becomes food for ants, spiders, praying mantids, etc. and when larger, the caterpillars (particularly admirals) also run the gauntlet of birds, wasps, parasitoids, and of course the praying mantis. Wasps, mantids, parasitoids and even hedgehogs will consume the pupae, so there is a large mortality rate even before the butterfly stage is reached. Disease in large communities of larvae can take a toll, and scientists estimate that with butterfly species generally, less than 5% of eggs reach the adult butterfly stage.

    Drought periods impact on nettle species in the wild, but with a little care various nettle species can be grown at home. Seeds of Urtica ferox, the tree nettle, are obtainable from NZ Seeds, and Urtica dioica, although classed as a weed and is banned in a few districts in New Zealand, is the one I use successfully. Although nettle was once found growing around the outskirts of parks and reserves, which resulted in urban appearances of the Red admiral, it is now rare to find it, but can occasionally be found on back country farms that have been neglected, particularly around water troughs or under shelter belts of trees where stock shelter, as the plants love nitrogen.

    Reproduction of the plant is from the rhizome, which can grow up to 1.5 m. in a season and send up new growth along the length, or from seed.

    The Red admiral is a forest butterfly, occasionally appearing in gardens seeking nectar plants and hostplants, whereas the Yellow admiral is more an urban or garden species, the numbers of which are thought to be boosted by Australian migrants windborne across the Tasman. Like Monarchs, some form of protection is needed both for the plants and the caterpillars. Nettles need a good feed of nitrogen occasionally, some shade, and moist soil to thrive. Covering the plants with curtaining or mosquito netting also protects the caterpillars, or even better containment such as a castle. Like pets, a little care is required for best results.

    Research has been carried out on the NZ Red admiral:

    https://researcharchive.lincoln.ac.nz/handle/10182/1763

    Further information on parasitic wasps in relation to the admirals can be sourced by googling – Echthromorpha intricatoria – and Pteromalus puparum.

    #57828

    nigelrc
    Participant

    Good to get this input. Seems as if availability of preferred foodplants as well as predation by parasitic flies might be the determining factors in the success or otherwise of the Admiral population in Northland, NZ. It’s true that nettles of almost any type seem almost non-existent in this part of the country.

    #57826

    Terry
    Participant

    Hi, Jacqui and all on this thread!
    My project will reach 23 years if I can get the Yellow Admirals through another cold English winter. I am not the best person to comment on nettles in New Zealand and where to find them. Norm Twigge who actually lives there like you is better qualified. I noticed many years ago on my trip to New Zealand how difficult it is to find quantities of any nettles unlike in the UK where they are abundant. I find that the Perennial Nettle urtica dioica works best for me but then that is the dominant species. The Small Nettle urtica urens can be found where I live but it is harder to grow and thus I use it less. I have bred the New Zealand Red Admiral in captivity in the past and they would lay eggs on urtica urens but mostly preferred urtica dioica. I know that in New Zealand for some strange reason the latter is declared a pest species and can be illegal to grow but in my humble opinion this is ridiculous as it is common here in the UK but is not a problem to our farmers and is easily sprayed off. If Red Admirals are scarcer in the north of New Zealand it would be due to lack of available nettles above all other factors.

    #57823

    Jacqui
    Moderator

    Great to get this discussion going! BTW, have you seen the excellent publication that Terry Smithers put together about raising yellow admirals? His project has been running for some years, and he’s in the UK!!! Hopefully he will contribute but you can see his booklet here – it might be helpful.

    https://www.monarch.org.nz/wp-content/uploads/2009/03/yellow-admiral-breeding-programme.pdf

    Also, Norm Twigge knows a lot about the parasitic wasps that affect admirals. Hopefully he may have time to contribute some useful information on the subject.

    Cheers

    Jacqui

    #57800

    fiona douglas
    Participant

    Thanks Nigel and Elizabeth. Last summer I collected some nettle plants from Elizabeth’s in Mt Tiger and brought them to Kensington (Whangarei). I used Elizabeth’s method of bringing them inside when the larvae had hatched and letting them pupate and emerge indoors. From memory, I had mostly yellows but a few red Admirals and released them back outside.

    #57799

    nigelrc
    Participant

    Thanks for your useful observations & information, Elizabeth. I suspect one of the reasons for the scarcity of Red Admirals in Northland is that the native bush nettle (Urtica ferox), does not generally thrive in our humid climate, & is in fact rather rare in this part of the country. The Red Admiral appears to require this species to successfully sustain its population. Like you, I have attempted to grow this nettle in one Northland garden but it was very prone to slug & snail damage & proved difficult to sustain, particularly through dry spells. Before it succumbed, it did, even as quite small plants, attract one or two Red Admirals.

    But I think there is another significant problem that also affects the Yellow Admiral, & that is predation by probably more than one variety of parasitic wasp or fly. I had a large crop of Yellow Admiral caterpillars on my European nettles in early summer 2018 but was disappointed to note that very few seemed to survive to butterfly stage. I even found one or two chrysalids which never hatched & on close inspection observed a tiny hole where a parasitic fly had presumably emerged. I doubt whether there is much if any research into parasitic predation of native lepidoptera species so we are reliant on the careful observation of interested amateurs. It seems likely that this sort of predation might also be affecting the Forest Ringlet. We can only hope that the Research Project will throw further light on the problem.

    Sadly,it is not a realistic possibility for someone with a small town garden to prevent predation by protecting foodplants, at least on any significant scale…and even covering plants with gauze or mesh will not necessarily exclude small varieties of parasitic wasps or flies. I hope that some ideas might emerge about how to combat what appears to be a destructive imbalance in the predation of our native lepidoptera.

    #57798

    Elizabeth
    Participant

    I live on Mt Tiger and for nearly 20years now have been on “butterfly duty” during the season, taking nettles/swan plants/ragwort indoors to rear caterpillars in safety, then releasing butterflies back outside. I did try native nettles, but they didn’t like it in the garden or were eaten by slugs, so have stuck with the European nettles that you too have in your garden. Several years ago we used to see quite a few Red Admirals around, as well as the Yellows. Also reared a small number and released them too. But for the last two or three years, hardly any Reds sighted at all, and none reared. I take nettles with tiny, just-hatched caterpillars indoors, so they can be Reds or Yellows – I have no way of knowing till they pupate. But always many, many more Yellows than Reds emerged as butterflies.

    So I don’t know the reason for the decline in Reds here at Mt Tiger, which is very disappointing. I had hoped I might help to boost the numbers, but sadly not. We have one acre of “garden” – mixed flowers, shrubs, veg, trees including both natives and orchard, and grassy areas including rough areas. We have neighbours’ paddock to one side of us and native bush on the other sides, so Red Admirals should be happy with bush being nearby, I’d have thought. I have read that Reds like the native tree nettle (urtica ferox), so you might like to try that to attract them – ours was eaten by slugs when quite small, and I didn’t feel brave enough to try again! Especially as at that point they seemed to be quite happy laying eggs on European nettles.

    I’d be interested to know if you know how many Yellow Admirals in your garden survive the wasps etc and make it through to pupae and beyond. I started bringing mine inside as I could see the survival rate outside wasn’t great. Maybe in the town there are less predators? We have a very insect-rich property, which is great in some ways of course.

    The Ragwort I bring indoors is to help along the Magpie moth caterpillars, which we see several of during the Summer. We also regularly see Common Coppers – saw one on flowers in the garden last week in fact, quite early for them. And for the last three Summers we’ve had one or two Painted Lady butterflies (vanessa kershawi)on Buddleia. But of course they come over from Australia and I don’t think breed here. And plenty of Common Blue – and Monarchs too.

    I think that’s about all I can think of about the butterflies etc at Mt Tiger. If you have any further questions I’d be happy to try to answer them, not that I’m in any way an expert. elizamber@hotmail.com

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