Monday, April 02, 2012

D. Balasubramanian on Democratic Societies in Animal Species

In the latest column in his fortnightly Speaking of Science series in The Hindu, Prof. Balasubramanian does a great job of presenting in a popular format a bunch of studies of social lives of animal species -- wasps and cockroaches, red deer and chimpanzees. Fascinating stuff!

Here's the section where he talks about the work of Prof. Raghavendra Gadagkar, a colleague in the Centre for Ecological Sciences at IISc:

Professor Raghavendra Gadagkar of the Indian Institute of Science at Bangalore is a well known “eusociologist” who specializes in insect group behaviour of wasps and bees. He recently described to us how a colony of wasps or bees organizes itself and optimises resources. He points out that while the colony has a queen, workers and drones, this is no monarchy. The queen does not proclaim what the colony should do. (We call her the queen, rather anthropomorphically, since all she does is sit around and lay eggs, and is pampered by a retinue of ‘assistants').

She too is just a worker, a special type of worker whose job is just to keep on laying eggs. There are no palace intrigues, and she too can be, and is, overthrown or displaced by another ‘egg laying machine'. When the colony is divided into two, the second queen-less part makes its own queen.

The “queen” is of course more important than the average worker, but she is not a dictator whose order the colony must obey. It is a group activity, with each member playing its role by common agreement.

How do scientists design experiments to answer questions such as "Do members of species X "practice a ... form of democracy"? Balasubramanian gives an example from the work on cockroaches:

How does one devise an experiment to arrive at such an important conclusion? Halloy's experiment was simple and decisive. He placed the group of cockroaches in a large dish that had three shelters.

The cockroaches did much “consultation” among themselves by touching and probing each other through their antennae, and after such consultation, divided themselves into groups and ran towards the shelters, away from the light (recall they like dark and no light).

The surprise was in the result. Each shelter could hold 50 insects. Yet when 50 cockroaches were used in the experiment, they divided themselves into two groups — 25 went off to shelter 1 and 25 to shelter 2, leaving shelter 3 vacant. When the researchers brought far larger shelters, each housing far more than 50, the cockroaches formed a single group and all went into a single shelter.