Τετάρτη, 23 Μαρτίου 2011

The juvenile locusts are brightly coloured, but it's the adults that should carry a colour warning as they can secrete poisonous foam from their joints.

 We are still in Ponta Malongane, trying to get footage of turtles. We do, however, have time in the day to explore the surrounding area. In the forested dunes close to the camp, we have seen many interesting little creatures.

The ones we found the most compelling in their behaviour were these green milkweed locust nymphs. They are often seen at this time of year travelling together in groups of up to fifty nymphs. Moving in a curious stop-start fashion, always keeping within feeler distance of one another. Their bright colours warn predators of the danger of toxins. Although it is believed that at this stage of their development, their bright colours remain a bluff as they have not yet developed toxins. Therefore, they resort to safety in numbers.
As they grow older and larger (up to about five centimetres in length) they will lose these colours and become more camouflaged. They will also have had the time to ingest the poisons from the milkweed tree or similar species and prepare it as a defense mechanism. When threatened, they secrete a poisonous foam from their thoracic joints. There are recorded cases of animal and human fatalities from ingesting these locusts -  another remarkable case of evolution at work.
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