Thursday, May 19, 2011

Ants in Kerala

I never cease to wonder at the amazing diversity of life in the tropics. Even the smallest patches of land seem to be home to so many different types of plants, insects, reptiles and birds!

The question for the day is this: How many different species of ants can there be in a 11 "cent"* plot in Trivandrum, Kerala?

A few years ago, I would have been content to divide ants into two broad categories - the ones that bite and those that didn't. That was, of course, before the age of WWW and online databases. But even now, the material available in these databases seem to have a limited coverage of the Indian subcontinent - let alone separate eco-zones and sub-zones within countries.

This dilemma was solved recently when a biologist friend handed me just the sort of book I was looking for - "On a Trail With Ants - A Handbook of the Ants of Peninsular India", a self-published book by Ajay Narendra and Sunil Kumar M.

Here is a list of local ant species that have been identified so far -
NOTE: Three broad parts to an ant – head, mesoma, and gaster. The head portion contains the antennae (funiculus), eyes and teeth (mandibles); the legs are attached to mesoma ( middle) segments and the gaster is bulbous portion at the rear and sometimes bears a sting.

1. Weaver Ant (Oecophylla smaragdina)

Weaver-ant soldiers keep a sharp eye on the males (black, winged), preventing them from flying away until the time is just right. Featured in National Geographic of May 2011.

2. Miniscule House Ant (Tetramorium smithi): Subfamily Myrmicinae.: Tiny (2mm) red-ants with a sharp bite

3. Golden Backed Ant (Camponotus sericeus): Lone foragers with workers in different sizes (polymorphic), ranging from 10mm to 4mm

4. Odor Ant (Tapimoma melanocephalum): Sub-family: Dolichoderinae: The most commonly seen ants indoors - its everywhere – clothes, curtains and even laptops! Seems to have supplanted the MHA a few years ago. 1.5 -2mm length; distinct pale yellowish gaster; long antennae

5. Pharaoh Ant (Monomorium pharaonis) : Subfamily Myrmicinae [Note: Id. to be confirmed]. Workers in sizes ranging from deep maroon head and gaster with reddish. Location: Outdoors – around the potted plants.
Pharaoh Ant - assorted sizes on a garden wall

6. Giant Honey Ant (Camponotus irritans)[Note: Id. to be confirmed] <>  Fast moving solitary hunter. Location: Indoors – mainly in the ground-floor bathrooms.

7. White-footed Ghost Ant (Technomyrmex albipes) Subfamily: Dolichoderinae: Shiny black ant 2.5-3mm long, with an oval,  pointy gaster. Recently hopped across from the banana fronds touching my  window to look for food in my dust bin. Location: Outdoors on banana fronds; indoors in the window sill. This ant figures in the PCI list of common Indian pests.
White-footed Ghost Ant

8. Yellow Crazy Ant (Anoplolepis gracilipes) Sub-family: Formicinae: Red transluscent ants, 6.5-7mm long with large gasters. Invasive species, indicates human disturbance in habitat.  <> Location: Indoors and outdoors.

9. Common Godzilla Ant (Camponotus compressus) Subfamily Formicinae: Black, opaque ant having workers in at least three different sizes ranging from 16mm to 8mm. Forage in small groups. Location: Exclusively outdoors.

10. Black Crazy Ant (Paratrechina longicornis) Subfamily Formicinae: About 3.5mm in length this ant’s main characteristic is its long, slender antenna. Location: Mainly indoors.

11. Greater Trap-Jaw Ant (Ondontomachus haematodus): About 15mm long this ant forages solitarily with its mandibles wide open. Location: only in the front-yard.

12. Finned Dolly Ant (Dolichodorus affinis) - Always a loner, this ant was spotted atop a banana tree. About 4mm in size, it is distinctly different with its deep, shiny maroon body - the gaster glints like a jewel in sunlight!

13. Common Red Fire Ant (Solenopsis geminata: Large nests on the steps leading to Parai Kovil, marked by heaps of powdery red soil particles.

14. Arched Two-spined Ant (Polyarchis halidayi)   [Note: Id. to be confirmed]: Atop a sapota-tree, hangs a nest made out of a single folded leaf walled with mud and larval silk. Home to about 20 ants. When disturbed the ants rush out and arch themselves into a defensive position, exposing the underside of their gasters which have a distinct black, metallic silver color.

14. Unidentified...which one is this??

*Note: 1 "Cent" =  40.5 sq m

Excerpt from NatGeo  article of May 2011:
Scientists have likened weaver ant communication to a type of language with primitive syntax,. Mathematicians draw upon analysis of ant behavior to devise parallel computing formulas (where multiple problems are solved simultaneously). Ants serve as models of all kinds of studies aimed at figuring out how big, complex jobs get done with small parts and minimum instructions.



Mumbai Bikers said...

Thank you for the post with images.
Good explanation.

I guess below mentioned post will interest you.

Charles Davison said...

Good reading.ants are pest controllers though themselves become pests.recently we cut diwn a mango tree becoz of weaver ants problem.huge colonies do create irritation.since we dont know how to restrict their colonies

Dinakarr said...

Thanks, Charles. Yes, the ant nests do indeed turn out to be a problem sometimes, especially for children who love mangoes and tree-climbing. On the other hand they also help you in keeping your fruit orchards free from a wide range of insects. So in Kerala, we actually encourage them by linking trees with strings so that they can cross the 'bridge' and keep guard on the other trees as well!