Saturday, October 10, 2015

The mantis guide to keeping geckos away

Many insects show resemblances to organisms that are well-protected. Some are examples of mimicry while a few others may be cases of convergent evolution. The evolution of behaviours that aid resemblance is often much harder to notice. For one, there is too much dependance on specimens and too little attention given to observation of living organisms. I have heard of a wonderful field botanist who would be unable to walk more than a kilometer an hour simply because the plants he saw on the way kept him so busy and occupied. It seems that the more trained one is as an observer, the more there is to see. Those with roving and restless eyes on the other hand quickly get bored and have a burning desire to seek novelty in far away places.

Here is something that you might spot right around your home. This nymph of a mantis in the genus Amorphoscelis waggles its abdomen in the style of a reptile. The most likely model, that is the species it has evolved to mimic, is a gecko in the genus Cnemaspis. These diurnal geckos are the most common ones found on tree trunks and they are most likely potential predators of these mantises. This aggressive stance presumably keeps geckos away.

The video below, rather poorly taken with low end equipment, shows this behaviour. I have seen the species in my strip of garden in Bangalore but this one was in the Eastern Ghats of Tamil Nadu. Notice how the mantis leaps and continues to run at the end of the video. Even this is extremely geckoesque.


And here is a very different and large gecko (genus Eublepharis) showing very similar tail waving behaviour. I have not found any videos of Cnemaspis as yet.

Illustrating the fact that behavioural observations have much to offer is a 2012 study of cryptically coloured moths and how they choose to sit on tree trunks. See the movie links at the end of the study.
Also see my older posts on lycaenid tails, spider mimicry and ant mimicry. And for some truly amazing caudal luring (the opposite of what is happening here) see this video of the spider-tailed horned viper. The tale of tails is long and complex.