Wild populations of Hyalophora cecropia in Europe

    Hello fellow entomologists!


    I have this question, and by searching on the English web I couldn't find any information about this, so I thought I'll have to ask about it on these forums.


    Do you know of any stable local wild populations of Hyalophora cecropia, or other American saturnids (say, Actias luna), to occur in wild habitats in Europe, be it in Germany or UK, or elsewhere.


    I think, as there are so many breeders of these moths in Europe, the moths could have, voluntarily or not, been introduced to wild habitats somewhere -- for example, by releasing a female full of eggs, or by releasing the excess larvae on trees growing outside.


    As the climate here is very similar to that of places of North America where these moths occur naturally, the climate shouldn't be an issue.
    There's plenty of hostplants for the larvae everywhere, too.


    So why I couldn't find any information about wild populations of these moths in Europe?


    Maybe most of breeders are aware of the dangers of invasive species, so they are very cautious to not let the moth escape outside?
    Though these moths don't seem to be very agressively spreading ones, so they shouldn't cause significant change to native ecosystems.


    Maybe here in Europe the predators of these moths are much more severe, so any established populations get eliminated very quickly, by, say, specific birds and bats who attack the large moths and larvae much more than in the America, or maybe the parasitoids in Europe are the main problem.


    Or maybe some healthy, stable populations do actually exist in some very localized areas, and those populations are still young, and haven't spread more, due to moths not being far-travellers.


    So what are your knowledge on this topic?

    • Your partner for good dried lepidoptera at fair prices" alt="LEPIDOPEXCHANGE
    ANZEIGE

    Hi,


    I don't think that the Saturnian species mentioned can escape breeding unnoticed. The caterpillars in the final stage are too large for this and the Imagos too slow in their flight behavior. At least most Saturniidae are not known to get started quickly to escape easily.
    And even if individual animals can escape, either a couple or a fertilized female, the right season, etc. is still necessary to take the first steps towards a new population.


    Fortunately, the fact that an entomologist overestimates one's own possibilities and common sense to such an extent that a deliberate exposure of such non-arial species has occurred has not yet happened, if one refrains from, for example, Samia cynthia, Graellsia isabellae, Antheraea yammamai.


    I think that a responsible entomologist can only expressly distance himself from such ambitions. Even if it were apparently "harmless" species such as Actias luna.
    The "wild" Asian silkworm species are enough.


    Leave the species where they occur naturally.
    None of us can estimate how foreign species can affect a well-established ecosystem.


    greeting
    Rudi

    I think it would take a deliberate release of a large number of animals to have even a chance of
    establishing a population out of their native range.
    Here in the states, where polyphemus is native, I tried releasing 50 adults at one time in an
    area where they're not normally found, I never found any evidence of a second brood the following year.
    Weather is a big factor that effects diapause and the moth's normal cycle. If they don't get the right
    climatic conditions, they're just not going to make it.

    The weather is a huge factor of course, but I still think that the weather in central-eastern Europe should be suitable for Cecropia or Polyphemus moths, because the region belongs to the same Köppen climate type as the regions of USA/Canada where these moths occur natively.
    More about this: en.wikipedia.org/wiki/Humid_continental_climate


    The Asian Saturniidae species (Samia cynthia, etc.) which were introduced to Europe and successfully established themselves here, all seem to be introduced because large numbers of animals were imported and bred here, with an intent to be used in silk industry.
    Of course, some of these moths escaped accidentally, or were deliberately released from breeding facilities.


    However, things like these haven't yet seem to have happened in Europe with non-native moths, which are only bred by hobbyist entomologists -- such as Cecropia or Polyphemus.


    This seems to indicate that hobbyist breeders haven't yet deliberately released sufficiently large numbers of animals specifically in order to establish a new local population.


    But nevertheless, it's still only a speculation of mine, and I don't know for sure that these moths would be able to actually handle the weather conditions and predatory environment of likely suitable locations in Europe.


    Maybe some of you have conducted some experiments on these N.American Saturnids, to test how they handle your local weather conditions and maybe even predators (if kept completely unprotected), throughout the year?


    For example, maybe somebody has placed some caterpillars on hostplants growing completely outside, and have regularly checked on them throughout the year, observing how they grew, made coccoons, and how the coccoons survived through the winter -- until the moth emerged the following year?

    Two Saturniidae species have been introduced to Europe. Samia cynthia (mentioned here) and Antheraea yamamai.
    Interesting is that both species have been introduced here deliberately, by people who were looking to exploit their populations for silk (sericulture). I think generally, the introduction of such a species requires a constant flow of introductions - the chance it happens from only a few escaped individuals is extremely low, as Rudi pointed out. The biggest threat would be people deliberately releasing animals. Even the famous Lymantria dispar in America was initially introduced by an entomologist who was free-breeding them in his garden - with no net to contain them - as an alternative for silk, until they began to spread.


    The good news is that, while a lot of harmful and invasive Lepidoptera exist, generally, Saturniidae are almost never considered 'harmful'; because of their large size and biomass they live in lower densities and have slower generations compared to some other harmful invasive species. This is however an overgeneralisation. Some types of Saturniidae (like Hylesia) can be an agricultural pest; but generally, being able to call a Saturniidae a 'pest' is rare.


    Though these moths don't seem to be very agressively spreading ones, so they shouldn't cause significant change to native ecosystem
    The problem is; how do you measure this?
    Every species you release into a new environment, alters it. Some alter it a lot, but damaging native trees and defoliating them. But on an immeasurable scale, species interactions also change. Maybe it's a new host for a parasitic fly that is otherwise rare, but boosts their numbers? Maybe they become the favorite prey of an insectivorous bird or bat which boosts their populations? They may even bring new micro organisms (diseases) with them and more.
    All of this is very hard to measure.
    Maybe, some of these changes are insignificant, but they are still there. And they can quickly add up.
    What if people introduce an invasive species together with an invasive host plant, and then an invasive parasite is introduced? This is what happened when Compsilura concinnata (Tachinidae) was introduced to destroy invasive Lymantria dispar; they also begun to attach many native populations of endangered American butterflies and moths. Oops.


    In that regard, I do consider myself to be a 'purist', and releasing exotic animals should strongly be discouraged. At worst, it will harm the environment, and at best, even species seems harmless - they still change it in some way, since every species has interactions with other species.


    In my breeding career I sell a lot of cocoons, but only three times (3) in 10 years did I have to decline an order to a customer, because they revealed their intentions of releasing the moths outdoors. In that case I refuse to sell to that customer in the future. The species were Danaus plexippus, Samia cynthia, and once Hyalophora cecropia.


    Note that it can also damage the reputation of our hobby, and get species outlawed.
    Much of the outlawed snakes, reptiles and fish in Europe, have been banned because they were proven to breed in the wild once escaped, or are considered to be too dangerous after an escaped animal injures a human. So I also consider other people who release exotic moths outdoors to be a threat to my hobby - and work.



    That being said, are there Saturniidae that would survive in Europe? Difficult question. I think the temperature is fine for most species, some come from much colder climates. But more complicated factors are precipation (humidity), light intensity, availability of host plant, et cetera.
    I think Antheraea polyphemus would definitely survive in the warmer parts of Europe. Maybe some of the northern Anisota species too. I'd also potentially nominate Caligula japonica in places with a mild winter (Balkans?) and maybe Opodipthera eucalypti in hot, dry places with Eucalyptus (Spain?) since they can also overwinter in New Zealand as introduced species. But who knows, I hope my speculation remains pointless here :smiling_face:

Jetzt mitmachen!

Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!

Benutzerkonto erstellen Anmelden