Common Mime – mimics the Blue tiger for protection from predators
I have been watching butterflies for the past one and a half years. Believe me it is an addictive hobby. Being not-so-lean I have tried dieting, zumba, gym and various other methods to shed extra pounds. Nature trails is the only form of exercise I enjoy and really push myself beyond my limits. It is a challenge for the mind too especially when it comes to identifying the species of butterflies. To confuse predators some butterflies like the Common Mime mimic the poisonous Blue tiger butterfly. It confuses butterfly watchers too.
Blue Tiger – a poisonous butterfly avoided by birds
By comparing images in detail at http://www.ifoundbutterflies.org and checking with experts in the field one can confidently identify the butterfly.
In my earlier post on Mimicking the tiger , the Daniad eggfly female mimicking the Plain tiger was discussed in detail.It is really fascinating as to how the butterflies have evolved to protect themselves from predators.
Here is an interesting account of Rana and Sugandhi’s blog post on the Common Mime pupa camouflaging itself into a twig for protection .
On one of our butterfly trails in Camp Gee Dee we found a group of Dark blue tiger – Tirumala septentrionis and the Double branded crow – Euploea sylvester butterflies feeding on roots of plants . These butterflies belong to the danaid family also known as the milkweed family , thrive on the juices of poisonous plants .
They feed on the toxic alkaloids found in certain plants.This action is supposedly to extract the chemical pyrrolizidine alkaloids from these plants to aid in their defense mechanisms and also to produce pheromones. When a hungry bird pecks on them, it triggers a fearful physiological reaction in the predator’s body. This result in predators learning this memorable aspect at first hand. Predators soon associate the patterns and habits of such butterfly species with unpalatability to avoid hunting them in future. A great deal of sexual selection happens based on this. Females select the most distasteful males to ensure a safety of the progeny.
Danaid eggfly Female mimicking the Plain tiger
Plain tiger – poisonous
The potential predators remember that the Danaids are unpalatable and avoid them . An interesting study by Dr Tom Eisner and his colleagues at Cornell University, U.S.A., working with the tiger moth . He observed that tiger moths are rejected by certain orb weaving spiders, which cut them from their webs rather than eat them. The Cornell researchers have shown that the moths are unpalatable to spiders and to birds because of the pyrrolizidine alkaloids the caterpillars gather from their food plants. The spiders will eat moths from caterpillars reared on an alkaloid-free diet, but find even their palatable items, such as mealworms, unacceptable as food when alkaloids have been added. Amazing to know how the predators have adapted .
The click of the Danaid eggfly female has bee downloaded from Wikimedia Commons
Few Interesting links on how a Single Gene Controls Mimicry Across Different Species
A link on how one butterfly species can gain its protective color pattern genes ready-made from a different species by interbreeding with it — a much faster process than having to evolve one’s color patterns from scratch