Posted tagged ‘butterfly’

Climate change and butterflies

23 March 2010

This report appeared in the Statesman on 19 Mar 2010. For the first time, cause-effect relationship between climate change and a living organism has been shown with regards to a butterfly, the Common Brown, Heteronympha merope in Melbourne.

Common Brown (Heteronympha merope)

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Butterfly antennas act like GPS!

17 November 2009

Its very easy for army officers to assume that journeying cross-country is simple. They forget that they are specially trained (in map-reading), specially equipped (with compass, GPS and maps) and there is a huge infrastructure ( of cartographers, satellites, high-quality printing presses, logistics, people to update) behind them!

Butterflies dont have maps or compasses....

Butterflies dont need compasses or maps...

Compare this with a butterfly? What could be the limits of its vision? How can it find its way across continents which are proportionally about a few hundred to thousand times larger? Without consciousness how do they do what they do?

And the only instrument they have for navigation is the sun in the sky!

...or GPS to help them migrate over areas they have never travelled before!

Lepidoptera migration is a great mystery!

Take the Monarch, for instance! This Danaid or Milkweed-family butterfly is universally known for its migration which has been well-documented and researched for over a hundred years. The state butterfly or state insect for eight American states, it is the most popular butterfly in North America.

Here’s a very nice look at the place the Monarch butterfly holds in the hearts of the American people!

Monarch Watch Spring 2009 Open House (on Catherine Sherman’s blog)

 

The Monarch (Danaus plexippus), a relative of India's Common and Plain Tigers, is a well-known migrant.

Wikipedia tells us about the Monarch’s migration that… :-

In North America, Monarch butterflies make massive southward migrations starting in August until the first frost. The northward return migration takes place in the spring. The monarch is the only butterfly that migrates both north and south as the birds do on a regular basis. But no single individual makes the entire round trip. Female monarchs deposit eggs for the next generation during these migrations.

Take the case of the population east of the Rocky Mountains. By the end of October, this population migrates to the sanctuaries of the Mariposa Monarca Biosphere Reserve in the Mexican states of Michoacán and México (the western population overwinters elsewhere).

The length of these journeys exceeds the normal lifespan of most monarchs, which is less than two months for butterflies born in early summer. The last generation of the summer enters into a non-reproductive phase known as diapause and may live seven months or more which enables it to migrate from the United States and over-winter in Mexico.

The generation that overwinters generally does not reproduce until it leaves the overwintering site sometime in February and March. It is thought that the overwinter population of those east of the Rockies may reach as far north as Texas and Oklahoma during the spring migration. It is the second, third and fourth generations that return to their northern locations in the United States and Canada in the spring.

Now,  how can a Monarch keep heading South throughout the day when the sun shifts its position from low on the horizon to its highest point at mid-day and again low in the evening?

As the Sun moves across the sky during the day, the Monarch must continuously adjust its calculations so that it does not waver from its chosen direction – South!.

Scientists have now found the key to the Monarch’s genius. It’s in the antennae!

The antennae of the Monarch play a vital role in navigtion during migration.

Researchers at the University of Massachusetts Medical School held the butterfly wings gently and dipped their antennas in enamel paint. They painted the antennas of one set of Monarch butterflies with black paint (which blocked both light and smell) and the antennas of another set were painted with clear paint (which blocked smell but permitted light).

The Monarchs with clear-painted antennas found their way around while those whose antennas were painted black-painted got lost!

That not only showed the antennas were sensing light for navigating, it also showed that the sense of smell isn’t involved in finding the way, since both paints blocked that ability.

And, since the animals with black paint got lost even though their eyes were able to see light, the researchers concluded the antennas were vital to finding the way.

Butterflies whose antennas were surgically removed also became disoriented.

Now how does this work?

In 2008, scientists of of the University of Massachusetts Medical School discovered that Monarchs have ancestral circadian clock mechanisms in their brain which tell them the relative time of the day. This circadian rhythm is formed by the production of and complex biochemical interaction of cryptochrome proteins, which act as critical components in the circadian clock mechanism. Two cryptochrome proteins, named Cry1 and Cry2 were also thought to connect the clock to the sun compass somehow for successful navigation.

This year, the new ‘antenna-painting’ study by this team proved that this sun compass was located in the antenna. Apparently, the antenna sun-compass gives Monarchs the ability to detect the position of the sun and the direction of polarized light.

Gif showing the great wanderings of the Monarch generations! (click to see the gif in action)

When this information is combined with time information from the circadian clock, monarchs are able to steer a course to the South each day and eventually to find their way from all over North America to the Mexican highlands, where they spend the winter.

Read more about it here and here!

Beautiful but deadly!

26 August 2009

It had just stopped raining in the  forests southwest of Binnaguri. The sky was overcast. Slowly, the ground absorbed the water which had not flowed away. Under the protective branches of a bush trying to reach high in the shady alcove of the forest, a flash of blue caught my attention.

The butterfly(?) resting on the underside of a leaf!
The butterfly(?) resting on the underside of a leaf!

Ah, a lovely butterfly, I thought as it  flashed its way to another such bunch of leaves. When I reached near, the wings opened and a gorgeous pattern of blue wings spotted with white emerged. I rejoiced for I had finally come across the most gaudy and colourful members of the Danaids or Crow family – the Blue Crows.

What I thought it was - Spotted Blue Crow (Euploea midamus)
Which butterfly I thought it was – Spotted Blue Crow (Euploea midamus)

Amazing buttterflies, the Blue Crows, like other Danaines, are inedible, fly slowly and leisurely flaunt their prominent markings which shout to all creatures of their poison and in-edibility. Once I had the butterfly cupped in my arms, I looked at it very carefully.

I realised that something was wrong but I couldn’t quite put my finger on it.

Suddenly realisation dawned.

The antennas looked strange because they were straight and had no clubbed endings. What I had in my hands was a moth!

The brilliant markings of the deadly moth!
The brilliant markings of the strange mimic moth!

Gingerly so as not to harm it, I held it one hand and photographed it with another.

It was really, really beautiful. It mimicked the Blue Crows to perfection; it looked like one. It flew like one. It behaved like one – slow dodging flight, not too difficult to catch, when caught it made body movements just like that made by a Crow, right down to the yellow tendrils waving from the tip of the abdomen. It was quite uncanny.

After a while, I released it and after a full day’s outing went back to my room.

Indian moths are hard to identify. There is a tremendous amount of work yet to be one. The only really comprehensive work, the Fauna of British India, (Moths) volumes, appeared in the last decade of the nineteenth century and was authored by G. F. Hampson.

Fauna of British India (Moths) Vol 1 - G.F. Hampson (1892)
Fauna of British India (Moths) Vol 1 – G.F. Hampson (1892)

But I did not have it at that time. Today it is freely downloadable at www.archive.org.

So I did the next best thing! I  requested identification on Indian Moths yahoogroup. It turned out to be a most interesting query and the moth turned out to be deadly!   Beautiful, but deadly.

Arif Siddiqui in Southeast Arunachal Pradesh responded first. He said that he had spotted the moth just about then and was thinking of  posting online for it’s id when he saw my post.  From Binnaguri to Jairampur, that’s 694 kilometers apart! A very goodly range indeed!

The two places, Binnaguri & Jairampur, where the butterflies were spotted at the same time. 695 kms apart.
The two places, Binnaguri & Jairampur, where the butterflies were spotted at the same time. 695 kms apart. (Image copyright & courtesy Google Earth)

We soon got it identified from Roger Kendrick, the guy in charge of all the Moths of Hong Kong (seriously ;-)). He told us that  –

<quote>

“This looks like the nominate subspecies of a burnet moth (family Zygaenidae, subfamily Chalcosiinae) that goes by the name of Cyclosia midamia, if Endo & Kishida (1999; Day-flying Moths: Chalcosiinae, Epicopeia; Endless Science Information, Tokyo) is anything to go by.

I wonder why people consider burnets as mimics. They are a more primitive group than most larger moths and butterflies – so it would seem logical that they are the original distasteful models that more recently eveloved taxa (especially Danainae) have evolved to mimic (in Müllerian mimicry rings).”

</unquote>

Okay, folks, once more for your comprehension, the moth was identified as :-

Cyclosia midama,  Herrich-Schäffer, 1853
Family Zygaenidae or the BURNET MOTHS (Subfamily Chalcosinae)

Disappointed that I had not discovered a species new to science, I decided to read up about “Cyclosia midama”. There wasn’t much. So I decided to read up the Burnet moth family, the Zygaenidae, instead. To my horror I discovered that not only are Burnet moths poisonous but they actually manufacture cyanide in their bodies..

quoting Wikipedia..

Zygaenid moths are typically day-flying with a slow fluttering flight, and with rather clubbed antennae. They generally have a metallic sheen and often prominent spots of red or yellow. The bright colours are a warning to predators that the moths are distasteful – they contain hydrogen cyanide throughout all stages of their life-cycle. Unlike most insects with such toxins, they manufacture these themselves rather than obtaining them from host plants. They are known to have mimicry complexes based on these toxins.”

and even worse….

“Larvae in two subfamilies, Chalcosiinae and Zygaeninae, have cavities in which they store the cyanide, and can excrete it as defensive droplets.”

I had been so cavalier in handling what was potentially a lethal animal. Tough I passed safely through that encounter, I shudder to think that I could have just as easily handled it more carelessly or even brushed a caterpillar….

The undersides, spotted white on black and blue.
The undersides, spotted white on black and blue.

This is a very important point that most naturalists who attain a certain degree of confidence (or is it overconfidence) forget. There are dangerous things out there in the jungle – and many times we don’t even recognise them. Zygaenids or burnet moths are very common in the tropics.  If you are a predator, its a good idea to avoid bright, prominent insects – as this is nature’s way of saying..

Stand off! Approach at your own peril!

Beautiful indeed but deadly!

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