Ant Fauna of Assam: A Case Study at Gauhati University Campus, Guwahati, Kamrup, Assam

Ants are the most abundant and successful organisms in the world. They attract human attention for their fascinating teamwork, disciplined movement, division of labor, selfless service to colony members, painful stinging, and unwanted presence in household items. They are the intelligent invertebrates that had initiated the practice of farming of fungi millions of years before human arrival, could build well-protected nests and territoriality, developed collective skills of foraging and mutualistic relationships with hemipteran insects for nutritional rewards, etc. In terrestrial ecosystems, ants play many vital roles that determine the health of the ecosystem as many other fauna and flora are directly or indirectly dependent on the ant community. The rapid changes in forest cover, land patterns, climatic conditions, etc., and over-dependency on pesticides and fertilizers impact on the ant community and diversity. Therefore, it is imperative to study this most dominant fauna at current times at least to document their present status and also to understand the health of the ecosystem and generate baseline information. The state of Assam in India is a part of the Eastern Himalaya biodiversity hotspot of the world but only a few studies on ant fauna have been carried out till now from this part. The existing checklist of ant species in Assam shows the presence of 217 species of ants under 58 genera. However, a detailed study of these ant species is needed. Gauhati University campus, Guwahati, Assam, offers a meeting place of different habitats viz. dense and fringed forests, hilly areas, natural and man-made wetlands, open plain fields, and undulating hilly terrain, grassland, cultivated area, protected botanical garden, human settlement area with concrete and Assam type buildings where chances of occurrence of diverse ant species are more. Hence this area is selected for the case study of ant fauna and recorded the presence of 41 species of ants that account for 18.89% of the total species recorded from the state. In the first chapter along with the general introduction about ants, we describe these 41 species of ants mentioning their morphological characteristics, feeding and nesting habitats, pest/predator status, and distribution.

Ants are generally avoided by predators for their equipped defensive strategies. Ant-mimicking spiders mimic ants morphologically to get protection from predators in one way and deceive their prey in another way. They chemically mimic ants to get constant resources and protection in the stable microhabitat that is the ant’s nest. As of now, a total of 13 families of spiders are known to show myrmecomorphy of which the majority of the myrmecomorphic spiders belong to Salticidae and Clubionidae families. Many species of the genus Myrmarachne of the Salticidae family show ant-like appearance with elongated bodies and narrow anterior abdominal parts giving the apparent shape of the petiole of ants. Mostly the ant species belonging to the sub-families Formicinae, Myrmicinae, Ponerinae, Pseudomyrmecinae, and Dolichoderinae are used as model organisms by different spider species. Some of the mimicry is highly species-specific and some are general. In the second chapter of the book, we discuss the myrmecomorphic spiders and their model ants. Studies about ant-mimicking spiders and their association with the model ants in India are still scanty. On the campus of Gauhati University, we encountered 10 ant-mimicking spiders which show morphological resemblance with different model ants present on the campus. Of the recorded myrmecomorphs, six species are under the genus Myrmarachne, and one species each from the genera Myrmaplata, Toxeus, Cambalida, and Apochinoma.

Many ant species are often seen visiting flowers. But whether they perform a pollination role has long been a topic of debate. A school of scientists opined that ants are poor pollinators as their body morphology, behavior, and chemical profile are against successful pollen transfer and pollen viability. Rather ants’ presence deters other potential pollinators from flowers. Another group of researchers claims that the flower-visiting ants only ward off inefficient pollinators, not the efficient ones. At the same time, in arid and semi-arid zones where winged pollinating insects are minimal or absent, certain ant species solely perform the role of pollination. In the third chapter, we discuss the flower-visiting ants and their functional roles in pollination based on existing literature. A list of flower-visiting ants recorded on the campus of Gauhati University is also presented.

Overall, these three chapters give a comprehensive idea about the ants of Assam, ant-mimicking spiders and their model ants, and the functional role of ants in pollination particularly in the context of the selected study site.