Ants are ubiquitous, hyper-diverse, and one of the oldest venomous arthropods on earth. They belong to the order Hymenoptera, which also includes sawflies, bees, and wasps. Ants, wasps, and bees share a common ancestor – a stinging wasp-like organism – and constitute the aculeata lineage. In Hymenoptera, females have modified their ovipositor into a stinger, which is connected to the venom gland, Dufour’s gland, and, in queens, to the ovaries. Venom, a cocktail of proteins, peptides, salts and amino acids, is an adaptive trait in certain organisms to fulfil their function like predation, defence from predators and microbes, and competition.  

While several venomous arthropods, such as wasps, scorpions and spiders, have been studied due to their medical relevance, ant venom cocktails are relatively untapped. Most studies on hymenoptera venoms are restricted to honeybees and wasps, while very few have focused on a handful of ant species, such as fire ants and giant red bull ants. My thesis aims to investigate Indian ants and shed light on their enigmatic and unexplored venoms.

My first chapter employs a proteo-transcriptomic approach to explore the venom of Indian ants: Tetraponera rufonigra (Bi-coloured arboreal ant), Myrmecaria brunnea (Brown Hunchback ant), Leptogenys processionalis (Razorjaw ant), and Diacamma indicum (Indian Queenless ant). These ant species were selected considering their habitat, ecological function, and evolutionary position. This chapter will unveil the composition of venom and how it is shaped by its deployment in distinct ecological contexts.

Seasonality is a major driver for several traits in arthropods, mainly due to their inability to maintain homeostasis, unlike vertebrates. The second chapter focuses on the plasticity of ant venom. By integrating proteo-transcriptomics and free amino acids profiling, this chapter will examine how seasonal changes influence venom composition and amounts. These findings will reveal how ants modify their venom cocktail to survive and thrive in fluctuating environmental conditions.

Eusociality, the division of labour within a colony, has evolved multiple times in the animal kingdom and has underpinned the evolutionary success of several lineages. An ant colony is divided into different casts like queen, worker (in some cases, major and minor workers) and drone. My third chapter will attempt to investigate the intra-colony venom variation across different working classes (casts). The results of this chapter will elucidate the influence of task specialisation on ant venoms.

Together, my thesis provides the first comprehensive analysis of Indian ant venom composition, highlighting its ecological, seasonal, and evolutionary dynamics. This study will open new avenues for future exploration in ecology, evolution, and biodiscovery research.