Sexual selection can favour the evolution and maintenance of highly elaborate traits in males. In many species, males show multiple morphological and behavioural-display traits. Though many studies have examined the role of sexual selection in shaping male display traits, they are typically done over a short part of the animal’s lifespan, and often in captive or semi-natural conditions. Patterns of variation in multiple display traits over the lifetime of individuals under natural ecological and social contexts are still not well understood. Apart from traits related to mate-acquisition, sexual selection can also influence behavioural traits involved in other aspects of an animal's ecology. Traits related to animal personality form one such set of traits. Research on consistent between-individual differences (called repeatability) in various behavioural traits related to personality is rapidly expanding. However, we know relatively little about patterns in repeatability in traits over a lifespan, especially in the wild, and the role of sexual selection processes in maintaining repeatability. With the motivation of studying sexual selection in the wild, I focus on examining the influence of sexual selection on male mating behaviour and personality in male Peninsular Rock Agama (*Psammophilus dorsalis*).

I first describe the natural history of the breeding system of this species. By following uniquely tagged individual lizards over their lifetime, I describe the breeding phenology and mating system of P. dorsalis. I then examine variation in multiple behavioural traits of breeding males and the influence of social context on these traits. My findings show that certain behavioural traits of displaying males show a strong pattern of covariation, are mostly directed towards females, and appear to carry predation costs. I also examine the relationship between these traits and indices of male mating success. To study the role of sexual selection in maintaining animal personality, I first quantified repeatability in risk-aversion behaviour. There is significant repeatability both in the short-term and over the lifespan of males. Finally, I examined the role of sexual selection by testing whether risk-responsiveness occurred in a behavioural syndrome with male display traits. However, I did not find evidence for the existence of a behavioural syndrome (i.e correlation) in personality traits measured across the contexts of mating and risk-aversion. Through such long-term behavioural monitoring of individual lizards, this thesis contributes towards a better understanding of the influence of sexual selection on multiple display traits, and on patterns in repeatability in display traits and risk-aversion, over the lifetime of an individual in the natural context.

The 19–49 My-old obligate mutualism between Macrotermitinae termites and the Termitomyces fungus is an example of an ancient agriculture system in which Termitomyces is cultivated by termites for nutrition. Termites, in
turn, keep other parasitic fungi like the parasitic weed Pseudoxylaria at bay. Unraveling the proximate mechanisms used in fungal cultivar protection is central to understanding the evolutionary stability of these farming mutualisms. We investigated the role of abiotic factors, antifungal chemicals and hygienic behaviours used by termites to keep their fungal gardens free from such parasitic fungi. Our results show the important role of abiotic factors such as termite mound temperature and CO2 in decreasing parasitic fungus growth. Using novel assays we also found that termites can display a differential behavioural response towards mutualistic and parasitic fungi and
that this behaviour is coupled with antifungal activity. These results not only shed new light on how the ecology of these fungi is affected by their host but also reveal the mechanistic basis that may contribute fundamentally to the evolutionary stability of this ancient mutualism.

Herbivore dung can be an important source of nutrients for soil. As most of the studies looking at the nutrient contribution from herbivore dung are based on agriculture with a focus on cattle dung, not much can be said about natural systems like tropical forests. In my thesis, I have looked at two aspects of herbivore dung decay: dung insect communities and dung-soil nutrient cycle. In order to understand the dynamics of the dung-soil nutrient cycle, we explored changes in dung nutrient composition above the soil and input of nutrients to the soil.

For my upcoming presentation, I will talk about second objective of my thesis, where I will be discussing transformation of dung above soil during the process of decay. Existing literature on biogeochemical changes during decay is limited to total carbon and total nitrogen. In this work, we have expanded existing knowledge with various important analyses: changes in carbon specific compounds such as lignin (recalcitrant component of dung) and sugar (easily decomposable), along with analytical pyrolysis to understand the overall changes. We explored the importance of initial nutrient composition in driving the rate of decomposition along with other factors such as seasonal changes and habitat type.

Observable patterns in nature, whether they concern morphological and molecular traits or range distributions, are caused by different processes. Through phylogenetics and post-tree analyses we can recover evolutionary trends and historical pathways along the history of organisms. In this talk, a few case studies from the evolution of flowering plants will be presented as means to understand character evolution and historical biogeography at broad and small scale.

Abstract: The relationship between regional climate and tree growth is not well understood in case of Himalayan conifers. In order to understand the response of trees to regional climate along an elevational gradient, tree ring chronologies of Abies pindrow are built at four elevational sites. The trees from different elevational sites respond differently to the local climatic variables. The positive correlation between growing season temperature and tree growth at low elevation site weakens with increasing elevation. The response to monthly precipitation also varies with increasing elevation. The response has changed in time as well in response to recent climate change. Also, different features of site chronologies like mean sensitivity, mean ring width, inter-series correlation etc. vary significantly with increasing elevation. This differential response of Abies pindrow to local climatic variables helps to understand the sensitivity of tree growth to climate at different elevations in a mountain system.

With the start of 21st century, climate change has caught attention of the world due to an increase in natural calamities, all of which have been attributed to climate change either directly or indirectly. There lies too much uncertainty in the possible role of soil in climate feedback, which on finer scale is regulated by microbes. With large body of literature available for the effect of climate change on soil carbon and microbes, there is still uncertainty on how soil microbial community is going to behave under projected climate change and change in land-use patterns. This has been further complicated by the heterogeneity of microbial community among ecosystems and different land-use. The proposed study would try to address various pathways and mechanism through which microbes function under different land use scenario and a glance into the possibility of microbes shaping the ecosystem in the wake of future
climate projections.

Over the years, multiple studies have tried to explain the patterns of species richness and distribution along different gradients through various hypotheses, all of which have equal support and criticism from different quarters. A consistent trend however observed across all these studies shows that most of these questions/hypotheses were studied at a narrow taxonomic level ie: for trees, ants or butterflies etc. but not for multi-taxa communities which coexist and share resources in the ecosystem. While many studies show patterns of different single-taxa communities varying or not varying across different gradients, very few explore this at a multi-taxa community level.
In this proposed study, we try to understand patterns of community structure using a multi-taxa approach along different anthropogenic and natural gradients, trying to understand whether a multi-taxa approach can provide better support to either of the many hypotheses trying to explain patterns along gradients and whether predictors of these patterns change from single-taxa to multi-taxa.

How biodiversity is generated and maintained is a fundamental question in
ecology and evolutionary biology, and studying diversification can give us
key insights into this process. In my thesis, I investigate diversification
patterns of lineage, morphology, and climatic niche, to understand the
underlying processes that have shaped these patterns in the historical
context of the Indian subcontinent. *Hemidactylus *geckos - commonly called
‘house geckos’ - are found in a wide range of habitats and climatic zones,
and are an excellent model system to address this question. My findings
indicate that climate has been a key factor shaping the morphological
diversification in this group. Understanding the broad ancestral climatic
niche of *Hemidactylus *also provides an insight into the climatic history
of Peninsular India.

Reproduction is the avenue for gaining direct fitness. But in certain
species some individuals do not reproduce to gain direct fitness, instead
gain indirect fitness by helping relatives to reproduce; the prime
examples for this come from the worker caste of social insects like ants,
bees and wasps. Indirect fitness has been in focus for explaining the
evolution of workers while overlooking the fact that workers can also gain
direct fitness. One of the avenues for gaining direct fitness by workers
is nest foundation and I have studied this phenomenon in a social wasp. I
found that workers prepare in several ways for nest foundation, like
enhancing nutrient reserve and engaging in dominant interactions, even
before leaving their natal nests. While investigating the emergence of
cooperation and division of labour in newly founded nests, I observed how
these affect the productivities of the new nests. Finally I found that it
is ageing and nutrition and not work done towards gaining indirect fitness
that affect workers’ potential of gaining future direct fitness by
independent reproduction.

The Indian subcontinent’s association at different time periods with different landmasses, and the intense climatic changes it has undergone have been evident in the presence of taxa with various biogeographic affiliations on the subcontinent. Studying the diversity and distribution patterns of the Indian biota will also help understand the role of these climatic and ecological processes in speciation. Due to their fossorial nature, blindsnakes have been a largely unexplored group. They are an excellent system to study, to further understand the role of India’s geological history in the present faunal distributions, given the evidence that they have various modes of dispersal, including oceanic dispersal. Some species are also quite widespread, spanning various biomes. This study aims to decipher the various biogeographical affiliations of the four genera of blindsnakes- Indotyphlops, Grypotyphlops, Argyrophis and Gerrhopilus - found in India, using an integrative approach. We also attempt to study the role of the establishment of monsoons and the subsequent aridification in the northern and central regions of India in the speciation processes that have resulted in the current blindsnake diversity. This will also help in understanding the actual diversity of this highly understudied group and resolve their taxonomy in the process.