Saturday, March 6, 2010

Glasswing Butterfly - Maree

The butterfly counts not months but moments, and has time enough.
~Rabindranath Tagore

Greta oto is a brush-footed butterfly, and is a member of the clearwing clade. Its wingspan is 2.2 to 2.4in (5.6 to 6.1cm) and you can see just about right through them.

If you want to see these ‘little mirrors’ in the wild, however, you will have to take a trip - anywhere from Mexico to Panama in Central America will do the trick. You will also have to locate the nearest rainforest as the understory of this environment is where the glasswing prospers. They feed off the nectar of a variety of rainforest flowers but when it comes to laying their eggs and ensuring the survival of the next generation, the glasswing has a fine trick up its (metaphorical) sleeve.

The glasswing, where possible, will lay its eggs on a plant of the genus ‘Cestrum’. Its common name, to you and I, is the Nightshade and it is highly poisonous. The caterpillars, which are striped in bright purple and red to warn possible predators, are thus a snack that birds and other animals will not enjoy at all. The alkaloids, a chemical in the plants that occurs naturally and is full of nitrogen, stay in the bodies of the glasswing in to adulthood meaning that even then they will not be an attractive meal.

Adults range from Mexico through Panama. G. oto visits common flowers like lantana, but prefers to lay its eggs on plants of the tropical nightshade genus Cestrum. The red and purple striped caterpillars feed on these toxic plants and store the alkaloids in their tissues, making them distasteful to predators such as birds. They retain their toxicity in adulthood. The same alkaloids that make them poisonous also are converted into pheromones by the males, which use them to attract females.

G. oto adults also exhibit a number of interesting behaviours, such as long migrations and lekking (gathering) among males.

Needless to say, as I have not been to any of the Central American rain forests! I did this sketch from a photograph in my Butterfly book. I would, however, LOVE to see them in real life!

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