Exploring Pigeon Valley: The False Dotted Border

This is the 99th article in an ongoing series that highlights the riches of Pigeon Valley, the urban nature reserve in the heart of Glenwood. The focus of this article is on the False Dotted Border.

As an antidote to the unhappiness around us, I thought I would present one of Pigeon Valley’s most colourful residents, with colours that are both soft and strong. What makes this butterfly ‘false’?

Before you become indignant over the dishonesty involved, a word of explanation. While this butterfly is very similar to the Common Dotted Border, they are not actually in the same family. A key point of difference (as of course you already know!) is that this butterfly has a row of black spots below the border of the wing, not just on the border.

ALSO READ: Exploring Pigeon Valley: The Male Spotted Eagle-Owl

This is about mimicry: some butterfly species evolve to appear like another, possibly quite unrelated species. One rationale is this: some species invest energy into developing protection against predators, such as poisons. Birds, for example, learn that butterflies with that appearance are poisonous, so they avoid them. So, if another species, just because of some chance mutation, starts to resemble that butterfly, it can get the advantages of protection without having to develop the poison.

The dishonesty thus works! This is a fairly complex topic, and there is constant research into exactly how mimicry works and the extent to which is successful. Crispin Hemson chairs the Friends of Pigeon Valley, a group that undertakes clearing of alien plants, keeps records of bird and mammal sightings and alerts management to any problems.

The Friends have a monthly walk at 7.30am on the second Saturday of each month. Email: friendsofpigeonvalley1@gmail.com.

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