Most distribution patterns in nature have been shaped by contemporaneous ecological processes as well as historical events. From a historical perspective, availability of dispersal routes and biotic interactions in evolutionary time as well as paleoclimate and geology have contributed to current distributions. In this regard, the Indian subcontinent provides us with an interesting setting to address questions in biogeography and phylogeography. This is because the Indian subcontinent has experienced diverse geological and climatic changes ever since it separated from Gondwanaland supercontinent. Given this background, one of the fundamental questions in Indian biogeography is, how, when and from where different groups colonized India.Furthermore how have these historical events contributed towards diversification within India.One of the approaches to understand the contribution of historical processes in shaping distributions is to study a system at multiple taxonomic levels.
I plan to address these question using freshwater snails as a model system. Freshwater snail families -Ampullariidae and Viviparidae have contrasting global distribution, suggesting different routes and time of colonization of India. This makes them an ideal system to test different hypothesis regarding their evolutionary origin. Additionally given their habitat preference and modes of dispersal, understanding genetic patterns within a species will be also an exciting area of enquiry. Bellamya bengalensis, a widespread species, is the ideal system to study such patterns in peninsular India. Hence, both biogeographic and phylogeographic studies will be implemented to understand diversity at various spatial and evolutionary scales.

Phoresy is an interspecific and temporary relationship in which the phoretic organism (traveller) actively seeks out its vehicle (carrier) for dispersal out of unsuitable areas for further development of itself or its progeny. In nature, this unsuitability of areas might arise due to over-crowding, habitat deterioration, sibling rivalry or unavailability of mates. These conditions generally lead to the development of a close association between the traveller and the host and the traveller might therefore also show synchrony with the host life cycle. The traveller not only needs to locate and latch on to its carrier but also should not have a greatly detrimental effect on the host which would prevent it from being transferred to a new favorable environment. Only few studies in phoresy have indicated that the carrier might bear the cost of such a relationship but this cost has not been adequately quantified. The addition of a third interactant leads to the development of a tritrophic interaction which increases the complexity of the system and might require an increase in the traveller’s specificity towards the carrier. One system in which nematodes show a highly species-specific tritrophic phoretic interaction is the well known mutualistic fig–fig wasp system.

In fig–fig wasp–nematode system, the fig nematode is the traveller, the female pollinator wasp serves as the vehicle and the fig is the substratum for their development. The pollinator wasp is the most reliable carrier as non-pollinator wasps that also occur within this system do not enter syconia in most fig species; the male fig wasps, being wingless, do not fly at all and die within their natal syconium. Such a phoretic system requires great specificity between nematodes and female pollinator wasps. Therefore, this system gives us an excellent opportunity to investigate the cost of phoresy on the mutualism between the fig and the fig wasp and the mechanism of dispersal of these phoretic organisms between figs.

Animal communication involves a transfer of information from signaller to receiver through different sensory channels. Effective communication between conspecifics can sometimes require the use of two or more sensory channels, making the communication multimodal. I am interested in understanding the phylogenetic patterns and ecological drivers of multimodal signalling. My study broadly revolves around three aspects of animal communication and signalling: morphology, behaviour, and environment. As a model system, I plan to use seven species of the day gecko, Cnemaspis, all of whom have male-specific throat-colour and femoral gland secretions that are likely used in social and sexual signalling.
My main objectives are to: Compare the signalling morphology of multiple species of Cnemaspis and determine whether there is a trade-off between visual and chemical signals; Quantify behavioural responses of male and female conspecifics to each visual and chemical signal separately and simultaneously and determine the relative importance of the two signals in multimodal communication; and Understand how current microhabitat conditions affect the morphology and behaviour associated with multimodal signalling in multiple species of Cnemaspis.

The communication system in the order Orthoptera (crickets, katydids, grasshoppers) consists of stationary males broadcasting species-specific acoustic signals which are used by females in conspecific recognition and localisation. Some species show deviation from this behaviour, engaging in duetting, with females also contributing to the signal repertoire and the males actively contributing to localisation. A unique duetting system was recently discovered in a katydid species Onomarchus uninotatus, where the females reply to a male’s call with vibratory signals and the male localises females using the vibrations. Laboratory experiments establish vibratory signals to be an immediate response to male calls even at the threshold of female hearing. This presents a paradox as the species is a canopy insect which limits the range of communication through vibratory signals. This is the first known case of female tremulation in response to the male acoustic call being used as a long-range signal. I plan to investigate the functioning of this multimodal duetting in the wild and the factors that could have led to the evolution of such a communication system.

The evolution of extreme form of altruism in the form of forsaking reproduction in order to help others to reproduce is arguably one of the most interesting paradoxes in biology. One of the theoretical frameworks that allows one to understand the evolution and maintenance of such behaviour is W D Hamilton's kin selection theory. *Ropalidia marginata*, a species of wasp in which generally only a single female lays all the eggs at a time, though most of the females are capable of developing their ovaries and laying eggs, is an excellent system to study the implications of this theory. One of the parameters in this framework is genetic relatedness. In my work I have estimated this parameter in the initial colony founding stage as well as in mature colonies. I have also constructed several models based on this framework in order to predict the next queen, and tested them. In addition I have studied the genetic structure of *R. marginata* populations. I found nestmate relatedness to be lower than the expected 0.75, with newly founded colonies having even lower average relatedness than mature ones. The queen's successor could not be predicted form any of the models. Regarding its population, *R. marginata* had quite high level of structuring and absence of any inbreeding. Moreover, structuring was higher at the level of the colonies.

A classic example of plant–animal interactions, galls are atypical structures that are formed on plants but provide nourishment and protection to the inducer organism and/or its progeny. Gall-inducing insects belong to a widely diverse group approximating about 13,000 species that can re-direct plant growth and physiology to their advantage, the exact mechanisms behind which are still unknown. The fig tree and its associated community of galling fig-wasps provide us a platform for studying the different potential stimuli contributing to gall induction. Additionally, the numerous wasp species with very different life history traits allow us to compare the different strategies that are employed by different gallers in a single syconium, all restricted by the same resource patch. We also hope to gain insights into nutrient flow in plants with special reference to how the fig tree controls the allocation of nutrients to different modules and how far does an associated fig-wasp override plant control in order to draw nutrients. The presence of both mutualist and cheater fig-wasps in the same fig elevates the conflict as the fig tree is expected to punish overexploitation without eliminating the mutualistic benefits.

Colobines are known to colonise habitats over a wide range from lower to
high altitudes, which makes them highly adaptive to different
environmental conditions. Higher altitudes being less productive with
decreased animal and plant density provide greater challenges for the
resident primate populations. Primates living in high altitudes are known
to cope up with challenges by adapting risky foraging strategies.
Most of the information about primate ecology and behaviour and diet in
particular comes from lowland habitats. Very few studies on Himalayan
langurs have coupled the primate diet with phenological data. In this
study I aim to understand the ecology and behaviour of Himalayan langurs
(Semnopithecus ajax). I will look into foraging strategies and diet
selection by them in different habitats across various seasons. Moreover,
I will try to understand the effects of human disturbance on feeding in
light of optimal foraging theory

Acoustic communication in orthopterans and anurans is a suitable model system to study sexual selection because the acoustic signals are generally produced by males to attract females over long distances for mating. Such systems provide an opportunity to explore the two operative mechanisms of sexual selection, male competition and female mate choice. In studies of sexual selection in these systems, the common approach has been to quantify male acoustic signal variation and to measure female preferences for different features of the acoustic signal using playback experiments, generally under laboratory conditions. A lack of ecologically relevant information on signal variation and female mate sampling strategies in wild populations, however, makes it difficult to assess the strength of selection and distinguish between the two mechanisms of sexual selection. Thus, for my thesis, I first quantified variation in male acoustic signals in a wild population of the field cricket species Plebeiogryllus guttiventris, in terms of amount of calling activity across multiple nights and the acoustic features of the advertisement signal within and across nights. I then went on to study female preferences for individual call features and the possible trade-offs when features co-varied. Finally, I explored female sampling strategies using experimental and computational approaches.

One of the central questions in ecology deals with understanding the processes underlying patterns in population abundance and the distribution of species at small and large spatial scales. The distribution of individuals of a species across a landscape may be influenced by local processes acting on births and deaths and propensity to dispersal; and by landscape-level processes influencing the colonisation and extinction of local populations and the movement of individuals between populations. Relatively few studies examine both sets of processes. Furthermore, the response of species to these ecological conditions may depend on species-specific traits, such as body size, behavior and other functional traits, but the roles of such functional traits is not fully understood. I propose to investigate the ecological processes at local and landscape levels influencing population densities by taking a behavioral ecological approach and using butterflies as a model system. Studying the behavior of individuals allows us to link population patterns with underlying ecological and evolutionary processes. While population ecological studies allow us to estimate the relationship between ecological variables (such as resource dispersion) and population densities, taking a behavioral ecological approach can help understand, from first principles, how resource dispersion influences populations by influencing different behavioral traits, e.g., individual movement, foraging rates, oviposition rates. These individual-level traits influence demographic parameters (e.g., fecundity, mortality, immigration, emigration rates) and thereby can influence population densities. I propose to focus on the influence of two key ecological factors, namely resource distribution and landscape composition. I propose to examine the influence of resource dispersion at local patch-level and landscape-level scales on butterfly behavior. I plan to examine how these relationships vary with functional traits of species and use this understanding to predict and test relationships between landscape composition and population density patterns of butterflies.

Vertebrate vision is one of the best studied and characterised of all biological transduction systems, but most of what is known comes from studies of birds, mammals
and fish. The relative neglect of snakes in modern studies of vision is surprising given that background information from historical studies indicates that snake
retinas are unusual and extremely diverse. Vision biology has also played an important role in debates about the evolutionary origins of snakes. Thus, studies of
snake vision could provide useful new information on vertebrate vision biology and vice versa. I will give an introduction to the topic and present insights from new
research.