An acoustic communication system consists of a sender, a receiver and a signal. In my thesis I have focused on the receiver. The model system I chose was the tree cricket species, Oecanthus henryi. In a cricket mating system, usually the male calls and the female recognizes and responds to the call. A female in a cricket mating system is thus faced with three kinds of issues: recognizing the conspecific call, localizing the call and discriminating among conspecific males based on individual differences in the calls. My thesis objectives are focused upon these three broad themes. I have examined the role of call carrier frequency in maintaining sender-receiver match thus aiding conspecific recognition. I have also explored the role of carrier frequency in discrimination among conspecific males. O. henryi is found in sympatry with a congeneric calling tree cricket species, O. indicus. I studied reproductive isolation between the two based on calls. Finally since O. henryi is found on bushes, the males and females are separated in azimuth as well as in elevation; hence I studied the mechanism of 3D sound localization in these insects.

Biological growth is coordinated over many time and length scales - right from the inner workings of the cell at the molecular level all the way to population level responses in the face of environmental changes. In this context, I will discuss biophysical mechanisms of size and growth control at the organelle, organism and population level. Using the multicellular nematode C. elegans I will address how an organism organises its cellular contents and regulates the size of its internal structures with functional consequences on growth. Interestingly, organism size itself governs developmental progression under changing food availability. Finally, I will present data showing worm populations modulate their investment in growth and reproduction when their food source is dynamically redistributed. Altogether, these table-top experiments provide an exciting opportunity to explore adaptive life history strategies with broad and important consequences in both developmental biology and ecology.

Open Data Kit (ODK) is a free and open-source set of tools which help organizations author, field, and manage mobile data collection solutions. ODK tools are versatile and designed to work in completely
offline environments. In this workshop, you will learn about different ODK tools and how to set them up for your field data collection project. You will learn how to use *ODK Build* to create forms, use *ODK Collect* android app to collect data and setup *ODK aggregate* server to collect and process field data. At the end of the workshop, you will take ODK out for a spin and carry out a field data collection exercise within the IISc campus.

Understanding species distribution and richness can contribute significantly to our knowledge of community assembly and macroecological patterns, as well as to the effective conservation of threatened species and habitats. Although there have been a plethora of studies on birds in India over the years, there is a critical need to accurately delineate species distributions and understand patterns of richness. The focus of this study was to understand the factors that influence the distribution of bird species in the Western Ghats, as well as to explore patterns in their geographic range sizes. These questions were addressed at the scale of the entire Western Ghats using a combination of primary field data comprising 78 one km transects across habitat types and a published secondary dataset comprising 57 transects. Multivariate analyses and species distribution modeling were used to examine the influence of environmental factors, and the relationship of floristics and vegetation structure on bird species distribution were explored using Mantel’s tests. Species distribution models also produced fine scale maps which were used to investigate patterns in range sizes in terms of species-specific traits and compared with currently available information on range. The specific approaches used to address these questions and the findings will be presented at the defense.

Understanding the processes that influence spatial patterns in species
richness and composition is central to ecology. A wide range of mechanisms
have been proposed but the struggle to find a universal explanation for
these patterns continues. The wet evergreen forests of the Western Ghats
provide an ideal setting to test the drivers of large scale variation in
species richness. We collected primary data comprising 20,400 occurrences
of 450 species of woody plants, and built a biome-wide species database,
to examine patterns of richness and composition along the entire
latitudinal extent of the Western Ghats. This study uses a macroecological
approach with a focus on species geographic range to uncover the
mechanisms that shape the diversity and distribution of woody plants in
the Western Ghats. We then use spatial, edaphic, topographic and climatic
variables to test the relative importance of niche based and dispersal
based processes in structuring spatial variation in species composition.
Finally, using the primary data collected on species occurrence and range
size, we establish for the first time, baseline data on the status and
distribution of woody plants and, following the IUCN criteria, carry out
species assessments for 250 species of endemic woody plants of the Western
Ghats.

The first half of the talk will essentially give an overview of game theory. Concepts of non cooperative and cooperative game theory will be illustrated using games and examples. The other part of the talk will present the use of game theory in understanding the competition of High Speed Rail (HSR) and other modes of transportation and their market strategies once HSR enters the market.

Given the economic and ecological values of coastal ecosystems in South East Asia, their preservation represent a tremendous environmental stake. Estuaries, mangroves and coral reefs, for example, provide resources and income for millions of inhabitants in these regions. However these ecosystems are severely threatened by anthropogenic and climatic pressure, which are often closely related. Recent findings have revealed that microbes and their viral parasites are highly abundant and dynamics in coastal waters. We also now know that they can quickly respond to environmental perturbations, and therefore represent excellent indicator of ecosystem health status. Here, we take the emblematic example of coral reefs in which the specific interactions between bacteria and viruses are now strongly suspected, according to the environmental conditions (water quality, temperature, salinity, contaminants, etc.), either to reinforce coral stability or conversely fasten their decline. Ongoing projects conducted in Vietnam aim at further investigating such poorly known mechanisms, which could promote the development of pioneer works for a better protection of marine resources.

Semi-arid ecosystems can exhibit striking vegetation patterns, which may have no characteristic size of patchiness. Elucidating local scale processes that generate these macroscopic patterns is of fundamental ecological importance. In addition, they may provide insights and tools to forecast the future dynamics of these highly vulnerable ecosystems that are prone to abrupt, irreversible shifts in vegetation cover, often resulting in desertification. I ask what information can be inferred from spatial vegetation patterns about an ecosystem and the processes driving it. I approach this question from two related angles. The first is from the context of scale and strength of underlying ecological interactions in a landscape. The second is from the context of regime shifts and spatial indicators of the same.

I begin by reviewing previous work done on bistability in ecosystems and spatial patterns indicative of approaching regime shifts. I briefly discuss the pros and deficiencies of existing spatial early warning signals of abrupt regime shifts (also called,discontinuous transition). I then propose and analyse a new metric, the power spectrum. I demonstrate that in combination with another widely used early warning signal - the probability distribution of vegetation patches in the system, it could provide a robust tool for detection of imminent discontinuous transitions.

The nature of regime-shifts (continuous/discontinuous) is determined by the underlying interactions in the system. Within this framework, I carry out further investigations of spatial patterns and the processes that they are signatures of. Most ecological interactions between species of the same trophic level (such as between different plants) can be simplified into two basic types – competition and facilitation. The relative scales over which interactions of each type are operational, could potentially determine the nature of the spatial patterns observed in vegetation over a landscape. I use cellular automaton models to simulate conditions with different scales of competitive and facilitative interactions in a system and analyse the resultant spatial patterns for signatures of these underlying rules.

The concept of sexual selection has been separated into two main components, male-male competition and female choice. Among these, female choice is probably the best studied and yet most controversial. Crickets are excellent model systems to study female choice due to their elaborate male advertisements, diverse female preferences and classic female-controlled mating. However, though crickets have been studied for a long time, most of these studies are entirely laboratory-based and do not examine female choice based on acoustic cues in the natural ecological context. Hence in my thesis I have tried to address female choice based on acoustic cues using a combination of laboratory and field studies with the tree cricket Oecanthus henryi as a model system. I started by examining male calling song variation and repeatability in the field, a prerequisite for understanding the available features for acoustically-based female choice. Following this I examined female preference for those call features which are reliable indicators of preferred male traits. I also examined the ecological context of female mate sampling to understand what a female actually faces in the field while choosing male traits. For this objective I examined male and female spatial organization, male sound field overlaps and female sampling opportunities. Using the information gathered from these two studies, I examined baffling behaviour in these crickets. Baffling is a unique behavior where males call from self-made holes in a leaf rather than calling from the leaf edge (their natural calling surface) thus increasing their loudness many-fold. I examined the context and advantages of baffling and the factors that may have led to its evolution.

The Elapidae (i.e. Coralsnakes, Cobras, Kraits, Mambas, Taipans and Sea-snakes) are a widely distributed, morphologically diverse, and highly venomous family of snakes whose evolutionary history and origin have been of enormous interest to biologists since the early 20th century. The traditional factor limiting a comprehensive, phylogenetic appraisal of the Elapidae has been the availability of samples of Old World Coralsnakes. Usually small, shy and fossorial, these animals are amongst the rarest venomous Asian snakes and their sampling, especially in molecular studies, has been sparse until now. Equipped with the most complete sampling of Old World Coralsnakes to-date, our research is for the first time investigating aspects of their radiation, including evolutionary relationships, temporal patterns of species diversification, and biogeographic history. Based on an integrative approach using molecular methods, morphology and geometric morphometrics, our results surprisingly suggest a basal phylogenetic position for Indian Coralsnakes and thus raise interesting implications that challenge the current scientific consensus on the early evolutionary history of elapids. The presentation will begin with a brief ‘ode’ to taxonomy and squamates before addressing the speaker’s primary research.