Lepidoptera in the Change of Times

(W-G.)

(Tagging this text with 'endangered species' too, even though this is lengthier article and in its whole discusses slightly different things. But, among worldly beautiful butterflies several are threatened. Also, pics from various butterfly-species mentioned would of course add this a more enchantment. Not included, because they are being such popular beauties and one with ease finds photographs in the net from these.)

Spring-time around the corner, we devote a few words to those lovely flying creatures repeatedly presented in our pic series – the butterflies. Numerous species exist in the scientific class of Lepidoptera, divided for three 'superfamilies': True (day-time) butterflies -Papilionoidea, skippers (Hesperioidea) and moths (Hedyloidea). Some older literature uses in taxonomy term Rhopalocera for them, but this actually was based on slightly different reasoning. Anyway, most from appeared in our series have been from the colorful day-time butterflies, but as calculated in Global Butterfly Names Project, there is about 180 000 different species in the world including all the superfamilies in count. They are found regular inhabitants in all the continents, expect (of course) Antarctica.

From some of their uses as human cultural artefacts, we can mention them as popular decoration motives (see pic right) also common fx in jewelery. Perhaps more excitingly, they also have often been a source of inspiration in human imagination and art especially because Lepidoptera species in birth go through 4 stages process called complete metamorphosis. A typical butterfly life-cycle consists from egg, larvae/caterpillar, Pupa/Chrysalis and finally imago/adult. This life-cycle may also include an inactive period in some of the pre-adult stages permitting them to pass over unsuitable environmental conditions (like winters fx).

The Wiki-articles inform us that all 'groups' in the main order (superfamilies) belong to most recent branch in evolution of the Lepidopterian species. These include currently some 60 per percentage from the whole, the rest consisting from more archaic forms of moths. Also since Lepidoptera tend to be less common habitants in areas favorable to preserve fossils (like lakes and ponds), there's generally less remains found from their early stages of evolution than from some other insects. Yet fossils exist, fx several found in Baltic amber(mostly from Eocene ca 50 Million year past) or in finer sediment levels which may have sometimes preserved their fragile formations. Earliest dated fossil from the order Archaeolepis mane (Dorset, UK) has been estimated to around 190 Ma years of age. So, oldest of them may have co-habitated the Earth around the age of Dinosaurs¹, in Jurassic period and therefore exceeding man's age to some 20 times further to prehistoric past – though it mentions only few fossils to exist from that far. Main feature in group is found in the formation of their scales(wings), also present in those prehistoric remains.

Butterflies are as diversified and variable group as their number of unique features would suggest. Most multitude of individual species is probably nowadays found in the Amazon rain forests, which also hosts some of the smallest and also largest butterflies (however, worlds largest day-time butterfly - not surprisingly its also endangered - is ^{Queen Alexandra's Birdwing} (Omithoptera alexandrae), wingspan reaching 30 cm and inhabiting the Papua New Guinea forests – nice pics and few lines about that here. Rainforest's species are rather exotic examples, at least from our urbanized view-point and the colorfulness of (many from) those large butterflies is renown. However, the more 'everyday'-species may also contain their own interesting particularities; fx. Let's take for example ^{Small Tortoiseshell}(Aglais urticae), a regular butterfly species that in nature habitats quite wide range from British Isles and continental Europe to the eastwards across Russia and Asia. According to Guinness Book of Records same species is mentioned to hold insects highest flying record, small group of these having been noticed flying over Eastern-Himalaya glaciers at altitude of 5791 meters.

In addition to being such large and peculiar group, the Lepidoptera of the world are also known to have their important roles in the natural life-cycle, especially in pollination. They also serve fx as food source for many birds. It then crosses our mind whether these lovely creatures have chances (better or worse) to survive that next man-made Harmageddon in our times; the Global warming, also often proclaimed with such horrific sounding terminologies and adjectives like irrevocable and irreversible? Remembering Lepidoptera species long evolutionary pasts and their wide diversity - around the Globe various kinds of species exist - one would at least suppose them having rather good chances.

So, basing on pure guessing it feels like/makes sense to suppose that Lepidoptera would likely come out as survivors. Arguments supporting this could be formed fx from the following qualities they do hold: I) Having wings, one would suppose this permitting (them) to move for more environmentally suitable areas if needed (and also many like 'longest traveling butterfly' Monarch ^{Danaus Plexippus} regularly migrate long distances) II) Also, like earlier mentioned, some butterflies lay eggs in late summer and these then go through a diapause stage and are not born until spring, mostly though in temperate regions(but overally this feature is common for many Lepidoptera). Further, some species common as regular habitats of cooler regions, like earlier mentioned Tortoiseshell and ^{Peacock butterfly} (Inachis io) are found to spend over-winter periods in hibernation stage, often in human built constructions and cabins fx. So feels like they could have potential to adapt for changes in seasonal cycles. III) In addition seems likely that their short life-cycles would also be benefit increasing that adaptavity (these actually vary a lot in between the singular species, some shortest living may fly only hours as adult while some others have been noticed to have a life span of nearly year).

So it seems we found at least few characteristics that would support our presupposition. But is all this relevant? Is it also so in real circumstances? More precisely; Do these suppositions actually have meaningfulness considering the effects of global warming, which perhaps affects in other harmful ways than just changes in seasonal periods? And does there exist any supporting/disputing scientific basis to our presumptions?

We then recollect this briefing from a study, which reminds us of dependence of the species from each other in nature; often other species may appear crucial for some other, and also as well some are expected to benefit from the warming while some others may possibly lose (as result). A potential for rapid revolutionary adaptation could (maybe) have a critical role in populations success. It then says also that capability to evolve, fx heat tolerance could become important in adaption to changing conditions. A study mentioned uses as test examples a couple Lady beetle species, but leaving these singular foundings then aside makes some overall conclusions too: As evolution in itself is rather complicated matter one cannot just look at certain species in Eco-systems, but have to “...think about the other species around it, and you have to think about the species' potential to change along with the environment.” Also, some species may often play a more important role in overall scenario. From this article (at Suite 101) we then find logical conclusions that if species has been harmed (severely) by other factors like habitat loss and degradation, pollution, disease, it probably has less chances for adaptation. Also, similarly reasonable seems to suppose mobility of populations as factor affecting to its chances. Whether an animal is generalist or specialist in food may affect. However, most interesting is the role of keystone species in nature: animals or plants that play a critical ecological role in certain ecosystem. The increased stress on these particular species and weakened populations of 'em then quickly affects many co-existing species. Which are the keystone species in (certain) Eco-systems varies likely in between different regions, but of course this is also a factor on which human actions can have big effect. Seems likely, especially concerning the seas, that among many keystone species overall pressure could often easily be reduced by limiting human uses (of ecosystem), I would suppose, fx by not over-hunting/fishing the particular species.

As for an evolutionary view-point to all this, we also throw in the(melting pot) this summary from studies. It informs us that noticeably some evolutionary changes in many species observed(squirrels, birds, mosquitoes) have already been found happening some 40 years. There is not yet any examples from genetic changes for increased heat tolerance, but the changes fx in their reproductions seasons timing and migratory habits may also be part of heritable genetic changes. As general rule, northern climates are becoming more like in south and species range are likely to adapt in situation. Then it also says that genetic shifts of seasonal behavior may be preceding the changes for increased heat tolerance. How soon such might take place is unknown but also it mentions that small animals with large populations and short life cycles are likely more able to persist in the changing climatic conditions than larger with longer reproduction times(like mammals). So, as expected, this also makes an argument in favor of insects like butterflies with such diversified variety. But then we have to still take in account that if certain important keystone species suffer that probably makes things more complicated for the others as well. As for examples in butterflies ecologic field of life, one would perhaps think certain important plants/flowers in related to this.

And as for better known typical animal relationships for many Lepidoptera (especially in sub-order Gossamer-winged butterflies, Lycaenidae) there's fx those whose caterpillars form symbiotic relation to ants. An example of that, rather wide-spread ^{Silver-studded Blue} (Plejebus argus); its caterpillar feeds some particular ants with sweet liquid, and those in return offer protection to it until the metamorphosis takes place. Ants not necessary play as crucial role for every other species, but that's an archetypical example from ecological companionships.

Finally, we can conclude all these speculations in few summaries: Basically most details found seem to support our optimism; Lepidoptera likely have several benefits permitting them in adapting to Climate Change. These include (in addition to our first three arguments) their small size, similar to most insects warming won't probably increase their physical stress that much. Also their brief life-cycles and large populations likely permit possibly needed quicker genetic mutations. What is more difficult to estimate is their particular place in ecosystems and how this may affect. Having not examined that, it is to a certain level a varying factor in between different species and their populations in differing regions, and so we would just make the supposition that changes in their particular habits and behavior being dependable on the rate of change. More rapid the warming, more rapid effects is of course easy to assume. Likely, as often in ecological imbalance, conditions increasing number of certain predators might effectively harvest them and lead to further consequences. From the mentioned butterflies in the begin of text the Tortoiseshell is known to have often had lots change in range and populations in different years, sometimes found numerous number at certain areas, and the following year not. This has sometimes been traced to the varying amount of certain wasps, feeding on butterflies larvae. Things like constant increase of such predators can probably harm particular species more severely, as these have less permanent effect in normal climatic conditions too. But, in case like that, one still feels that the large variety in Lepidoptera species and their capabilities to further their ranges would balance things to some level.

The time for serious warming expected to take is such brief period, some 100 years – a nanosecond in geological time-scale - after which temperatures are supposed to stabilize globally. So forth, one cannot quite make very trustful conclusions if the effects of that would be adequate to cause the significant genetic changes. Even if quickly reproductive species (like ones discussed here) would begin adapt genetically in during that period it is still feels a bit uncertain since such fast changes aren't probably reasonable in evolutionary basis. And likely we can suppose to find the most direct effects in changes of (fx) their migratory range and population behavior, and things of similar kind.

If one then remembers that butterfly species in the worlds are inhabiting such various temperature zones with ranges, it also feels like our optimism would have some ratified basis. Even so, and even remembering having it read somewhere that their main class (insects) actually is said to consist 98 per cent from the total number in animal species, it's still probable that also they will be harvested by increasing pollution and uses of pesticides. Also, as some scenarios of Climate Change expect it to wipe-out 25 to 50 percentage from animals populations in 100 years, seems probable that this would mean large number of Lepidoptera species as well. In addition to effects of warming some more direct human caused factors damaging the ecosystems will have effect (human land use, agriculture which will necessary increase in the future also pushes fx fertilizers in nature, a factor of some importance too). Another thing is that one could also point out that the mostly threatened in the future will be the ones most dependent on unique needs. That could mean fx. those that feed on only certain rare plants; also (most butterflies )usually lay their eggs on plant and each species have their own range of host plants, some being restricted limited to just certain plant species. Finally to mention, in future areas (the rain forests) inhabiting lots of the most appreciated and spectacular of the Lepidoptera-species are predicted to became more vulnerable to certain mass-scale environmental damages like forest fire, in addition to human (profit-making) destruction, which presents yet another threatening factor.

And going further, we're not in complete knowledge from the overall effects of changes in atmosphere which are to be seen and can consequently cause form some new threats. Say, that these are so called x-factors. Nevertheless, it would seem that we've reached quite expectable results(as our positive supposition was perhaps a starting point, more negative preconceptions would probably have given different views...). All this then also makes us as our conclusive judgements finally also give some remarks from yet another barbarous habit, that of (butterfly)-collecting (especially the endangered species) which obviously should be 'Strictly verboten!' Naturlich.

(Text) mostly collected from Wikipedian-information and few brief sources referenced in the text, there may be simplifications, or perhaps even minor errors, because these are just some contemplative thoughts.

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1. Also seems interesting to notice it being mentioned from the process of their evolution that during the mid-Cretaceous(ca. 100 Million years ago) the diversity of early forms of Lepidoptera developed along with the increase of flowering plants. This happened at the time when the latter mentioned also underwent an expansive adaptive radiation. As result in many of these (archaic) forms there was simultaneously general increase in size and better flying ability, fx. - So when the dinosaurs vanished, the various butterflies started to flourish (similarly to various other life-forms). Also, quite simultaneously took place the appearance of first species whose larvae feed on herbaceous plants, earlier forms having favored the woody plants.