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Lab Story: Tracking evolution in animals and insects: The Evolutionary Ecology Group

When evolutionary biologist Theodosius Dobzansky said, “nothing in biology makes sense except in the light of evolution,” he couldn’t have been more right. Evolution, the study of how traits are conserved or emerge over time, answers a lot of “whys” in biology: Why does an animal use a particular strategy to woo a mate? Why does a female decide to lay her eggs at a particular place and time? Why does competition arise within species? The Evolutionary Ecology Research Group at the Center for Ecological Sciences, Indian Institute of Science, works on answering many such questions.

Headed by Dr. Kavita Isvaran, the lab's research interests lie in studying the ecology and evolution of plant and animal behaviour. Her lab members work on understanding mating systems and sexual selection, the ecology of invasive species and foraging by the blackbuck, an antelope species native to the Indian subcontinent – niche areas under the umbrella of evolutionary ecology.

For instance, previous research in Dr. Isvaran's lab has highlighted the influence of foreign invasive species such as Lantana on native biodiversity, and subsequently on butterfly populations. An exotic invasive shrub, Lantana fiercely competes with local plants for water, nutrients and other resources. The team's research showed that butterflies evolve to inhabit areas with more plant diversity rather than those that had only Lantana growing in them.

Another area of research in the lab involves understanding the effects of habitat fragmentation, or splitting up of pristine animal habitats into small parts due to development of infrastructure and human activities. The lab members are interested in finding out how this will affect insects and their behavior. As pollinators, insects play a vital role in plant reproduction; changes in their behaviour and habitats will critically affect plant biodiversity.

Another question that intrigues the lab members is how female insects, such as mosquitoes, decide where to lay eggs in order to provide their offspring the best chance at survival. Called Oviposition Site Selection (OSS), this is an important decision that influences reproductive success, because the larvae of insects such as mosquitoes and butterflies cannot move from the deposited site until they reach maturity.

The lab is also interested in figuring out how males of certain bird, lizard and frog species try to attract females. For instance, male rock agamas (a type of lizard) sport a bright orange-red and black colour in contrast to the more drab females. The males also maintain and guard their territories fiercely, making it easy to identify and study them.

Understanding mating strategies in blackbucks is another area that the lab works on. The team proposed and tested one hypothesis: many male mammals have shorter life span than the females of their species because they invest much more energy into making sure their genes reach the next generation.

The lab also uses these threatened antelopes as model animals to analyze crop damage by large herbivores. These animals often move out of protected areas in search of easy food in agricultural fields. Understanding how they move between different landscapes and why they prefer certain types of food might help researchers find solutions to mitigate the damage that farmers incur.

Contact information:

Dr. Kavitha Isvaran

Centre for Ecological Sciences, Indian Institute of Science, Bangalore

Website: http://ces.iisc.ernet.in/kavita/index.html

Email: kavita@ces.iisc.ernet.in

Phone: 080-23600985/22932506