Tawny Coster (Acraea terpsicore)

A very easy for ID butterfly. As name suggests, wings are 'tawny' colored with black spots on it. Another characteristics is lazy flight, bit of like sailing - fluttering combination. Lot many specimens can be seen around its host plant passiflora sp. Host plant is a climber, flowers throughout the year. Tawny coster lays eggs in large batches, typically between 20 to 100. Caterpillar is tawny-reddish color, and has spines allover the body. Appearance is similar to pansy caterpillars. I brought one batch for observation consisted of 50+ eggs. Here are some observations:

1. Eggs hatched in 6-7 days, caterpillar ate for about 10 days and then pupated. Although food was sufficient, growth rate of the individual was different.This was well reflected in pupation and eclosion. Whole batch pupated over a period of 5-6 days.

2. Caterpillars were seen eating anything. Egg shells were eaten as soon as eggs hatched. Further they ate leaves, fruits, flowers and another pupa as well. Deliberately last few caterpillars were fed less to simulate scarcity of food. After finishing everything edible, except the twigs and other caterpillars, caterpillars started eating pupa. 

3. As pupa's were made on different days, eclosion by the individuals was seen over a period of 5-6 days. Interestingly eclosion was seen just 4-5 days after the pupation.

Top view of Tawny coster eggs

Tawny coster eggs

"God, please make me a beautiful butterfly", cat posing for pupa, pupation just started.

Coster lays eggs in large batches. Soon after this batch, I observed similar 4 more batches on the same plant. According to 'Butterflies of Peninsular India', this specie do not have any predator, even they have discovered a technique to escape from birds. Now the question is which factor limits the outburst of the species? Is it the caterpillar eating other pupa? but then what about the cases when reach and plenty of food is available? My guess is caterpillars are eaten by the predators in pupa stage, but its just a guess. Another answer to earlier question may be the sex ratio. I was unable to note the sex ratio. This could be a good exercise and may develop some insight on population control. 

Few numbers might be worth noting while life cycle observation:

1. Sex ratio

2. No of hatching (yield)

3. survival rate till pupation

4. Pupa formation and eclosion (day-wise)

Quick Facts:
Common Name: Tawny Coster
Scientific Name: Acraea terpsicore
Wingspan: approx 50-65 mm
Status: Common.

(Note: click to enlarge the pics and see them in full screen mode)

 

Scales of the Tawney Coster butterfly revealing the texture