1 Tahrcountry Musings: September 2008

Monday, September 29, 2008

Suicidal defense by Ants

The mysterious ways in which nature operates leaves me spellbound at times. New researches makes me realize that we have only touched the tip of the ice-berg. Here is another piece of news that makes you wonder. Ants are well-known for their willingness to die for their colonies. This usually occurs when enemies are present. New research by Adam Tofilski of the Agricultural University of Krakow, Poland, et al shows that the Brazilian ant Forelius pusillus goes for self-sacrifice to defend the colony. This is the first known example of a suicidal defense that is preemptive rather than a response to danger posed. At sunset the ants seal off entrances with sand, and a few ants remain outside to complete the job. These ants that remain outside are unable to reenter the colony. They die by the next morning. A short report appears in the latest issue of science magazine and the full paper appears in the in the November issue of the journal American Naturalist.

Tuesday, September 16, 2008

Prehistoric ant discovered in Amazon rainforest

An ancient ancestor of ants has been discovered living in the Amazon rainforest. The discovery was made by evolutionary biologist Christian Rabeling of the University of Texas at Austin, USA. The new ant is named Martialis heureka, which translates in to "ant from Mars," .This is to highlight the ant’s characteristics never before recorded. Ants evolved 120m years ago from wasp-like ancestors and quickly adapted to living in soil, trees and leaf litter. This is the first time that a new subfamily of ants with living species has been discovered since 1923. The discovery will help biologists better understand the biodiversity and evolution of ants. Tabeling says "This discovery hints at a wealth of species, possibly of great evolutionary importance, still hidden in the soils of the remaining rainforests,” The study appears in this week’s Proceedings of the National Academy of Sciences.

Wednesday, September 10, 2008

Live and let live - Predator species help each other while competing for a single prey

All of us are familiar with apportionment and rationing when there is a resource crunch. Nature resorting to this ploy might sound a wee bit farfetched. But this is exactly what scientists from Sweden and Netherlands have found out in their pursuit of intricacies of predator prey relationships. I was fascinated to read the paper “Stage-specific predator species help each other to persist while competing for a single prey” by A. M. De Roos et al. It gave me insights in to the myriad and mysterious ways in which nature works. In the wild state prey are usually shared by many predator species. One of the fundamental questions in ecology is how predators coexist while competing for the same prey. De Roos and associates with their research show that competing predator species may not only coexist on a single prey but even help each other to persist if they specialize on different life history stages of the prey. The research comes up with the finding that a predator may not be able to persist at all unless its competitor is also present. Net result is asymmetric increases in the rate of prey maturation and reproduction when predation relaxes competition among prey. This interdependence suggests that the network of feeding interactions in a community is, in fact, an emergent property of the system, which to a large extent arises through self-organization. Part and parcel of this self-organized character of the food web is an inherent fragility whereby the loss of a facilitating predator species may lead to subsequent extinction of some of its guild members, making the community collapse like a house of cards.

Stage-specific predator species help each other to persist while competing for a single prey
A. M. De Roos,T. Schellekens, T. Van Kooten and L. Persson
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94084, 1090 GB Amsterdam, The Netherlands; and Department of Ecology and Environmental Science, Umeå University, SE-90187 Umeå, Sweden

Tuesday, September 02, 2008

DNA bar-coding hitches

The ambitious project to DNA barcode all species (International Barcode of Life) has run in to a bit of rough weather. Scientists use a portion of the gene found in an organism's mitochondria for bar-coding. A new study by Brigham Young University has shown that the current techniques can mistakenly record the "broken" copy of the gene found in the nucleus of the organism's cells. This lapse will make present bar-coding technique to call it another unique species by mistake. This could lead to overestimating the number of species. To overcome this hitch, Brigham Young University has recommended specific quality control procedures to ensure that correct genes are captured. The day is not far off when a handheld device like a supermarket scanner is used to identify species. All that needs to be done is to compare the DNA marker from an organism with the known encyclopedia of life and immediately come out the species' name. 400,000 species have already been bar-coded to date. Exciting times are ahead for field biology scientists.