Giant Forest Ants (Camponotus gigas) and their ‘bloody fight’

One would never thought of ants getting into “bloody fights”. However, that’s exactly what the giant forest ants (Camponotus gigas) do in order to protect their territory. Found in Bukit Timah and the Central Catchment Nature Reserves (lekowala 2005), giant forest ants are distinctive black and reddish brown ants which can reach lengths of 30mm. They are primarily nocturnal (Pfeiffer & Linsenmair 1999), coming out of their nest to forage through the night. There are two forms of this species, namely the smaller minor workers and the larger major workers.

These larger major workers exhibit territorial behavior (interference competition mechanism) and are involve in both inter-specific competition as well as intra-specific competition. Their territorial behavior was evident in their nesting patterns, which are connected by trails through the forest canopy (Pfeiffer & Linsenmair 1999).

Giant Forest Ants (courtesy of Ria Tan, retrieved from http://www.wildsingapore.com/riablog/photos/040818cnr/photos/photo_12.html)

Giant Forest Ants (courtesy of Ria Tan, retrieved from http://www.wildsingapore.com/riablog/photos/040818cnr/photos/photo_12.html)

Inter-specific conflicts with sympatric Camponotus species always led to violent, “bloody” fights of all castes. It began with mass recruitment of workers, followed by violent fights, causing mass deaths. Besides using their mandible, they also sprayed acid and used their poison gland (Pfeiffer & Linsenmair 2001).

In contrast, intra-specific competition takes on a gentler approach known as ritual fights (Pfeiffer & Linsenmair 2001)(Fig. 1.), with a few specialist major meeting at fixed tournament places. They generally use their mandible for fighting. Usually, the fights would last the whole night (Pfeiffer & Linsenmair 1999). Surprisingly, ritual fights were a means that had evolved to minimize loss of “combats” as territorial competition can result in massive loss of workers on both sides. Interestingly, these fights can last for several months (Pfeiffer & Linsenmair 2001)!

References:

Camponotus gigas and the “art of war,” by lekowala. The Biology Refugia, 8 June 2005. URL: http://staff.science.nus.edu.sg/~sivasothi/biorefugia/archive/2005_06_01_archive.html (assessed on 7 April 2010).

Pfeiffer M. & Linsenmair K.E. (2001). Territoriality in the Malaysian giant ant Camponotus gigas (Hymenoptera/Formicidae). Japan Ethological Society and Springer, 19:75–85

Pfeiffer M. & Linsenmair K.E. (1999). Contributions to the life history of the Malaysian giant ant Camponotus gigas (Hymenoptera, Formicidae). Insectes soc, 47 (2000) 123–132