TBD

Natural history is the cornerstone of ecology from time immemorial. Anyone who been intrigued by some naturally occurring phenomena would agree that observing ecological systems or organisms in their natural settings is both incredibly challenging and, equally rewarding. Surely, there is also a subtle something about being out in the wilderness which drives a naturalist. Is it the satisfaction of seeing momentary truths? Is it the thrill in acquiring an intimate knowledge of the mysterious ways in which nature works? Is it the tranquility of the wild, away from the chaos and madness of our city life? Is it a quest for adventure? Or, an overzealous enthusiasm bordering crazy? I will take this opportunity with you all to look at a part of my life when I got on to the roof of the planet—the forest canopy. We shall briefly examine some of the aforementioned aspects and by doing so, I hope to shed light on how natural history has continued to shape my career as a biologist; assuage any feelings of “having taken the wrong turn” and, punch above my weight to draw out the field biologist in you.

Colobines are group of primates known to inhabit different habitats. These habitats pose diverse challenges which they have coped up physiologically and behaviourally. Primates in such environments are subjected to prolonged scarcity of food due to phenological variations and low temperature in winters. They are expected to allocate their time to various activities optimally in order to balance their energy requirements. One such primate inhabiting the harsh weather condition of Himalaya is Himalayan gray langur. Himalayan gray langur, Semnopithecus ajax, is little-known endangered primate, initially reported to be present in few parts of north-western Himalaya. To understand their survival strategies in these habitats one must know about the whereabouts of this species.

Therefore, I first accessed the spatial distribution and occurrence of Himalayan gray langur in Kashmir region. This was achieved by using well-structured questionnaire and on-ground surveys in the region. It was followed by identifying sites which face human-langur conflict. My results suggest a wider range of Himalayan gray langur in Kashmir which was previously thought to be restricted in a small range. Langurs were found distributed in the protected mountainous forest areas of Kashmir by showing a preference for broad-leaved deciduous and coniferous habitat types within 1600-3000 m. Conflict in the form of crop raiding was found in the villages around protected areas.

Based on the knowledge of the distribution of these primates in forests, I tried to address how this primate survives the seasonality and cold temperatures of Himalaya in the next chapters of my thesis. I have addressed this by investigating the behaviour patterns and the strategies they have adopted to balance the energy requirements. I used observational methods of instantaneous scans for different behaviour categories. My results suggest Himalayan langurs spend more time feeding during lean winter when high-quality food is less available and rest more during hotter months. Moreover, they have greater home range sizes in winter than in summer. These results suggest an energy maximizing strategy by these primates when resources are scarce by feeding more on less profitable food sources and expanding their home range size.

I further investigated the diet and feeding behaviour of langurs. They were found to shift their diet with seasonality. They feed on a variety of plant items ranging from bark, buds, young leaves, mature leaves, ripe fruits and seeds. I used resource selection functions to test for plant species preference. A seasonal preference for certain plant species and plant parts suggest that availability of plant parts influences their choices. From these results one can conclude that Himalayan gray langur has adapted to explore a variety of food sources other than leaves. This study helps us in understanding the ability of colobines to explore such versatile diets which has helped them colonize many habitats, one of them being the Himalaya.

Overall, this study provides a baseline information for conserving Himalayan gray langur through comprehensive understanding of its distribution, activity budget, home range, diet and feeding preference in Kashmir Himalaya. The current distribution serves as a base-map for various management policies towards the conservation of this high-altitude primate. Moreover, insights about the conflict will help managers in developing ideas to reduce and prevent conflict. Due to the presence of this species in the broad-leaved deciduous and coniferous forests of Kashmir, it becomes important to preserve and protect these habitats for its survival. The key findings of this study are expected to benefit directly towards the conservation of this species and in understanding the survival strategies of these high-altitude primates.

CES IHS 2020
Talks, Posters, Short documentaries, Panel discussion, Science and Creativity stalls

Territoriality associated with lek-mating systems is unique in that males defend small, heavily clustered territories that lack resources usually thought to attract females, such as food and water. Females visit these male aggregations (leks) solely for the purpose of mating. Males compete intensively to defend mating territories and male mating success is typically highly skewed. Males in this system face the complex problem of making decisions on how much effort to allocate towards territory defence and mate attraction efforts versus maintenance activities and how to time this effort, as the duration of territory tenure in relation to the peak in number of females visiting the lek has important fitness consequences. Associated with the high variance in mating success, there is extensive variation in the behaviour of males holding territories on leks. In my thesis, I attempt to understand this variation in male lekking behaviour, by examining patterns of territorial investment in relation to patterns of expected payoffs, estimating underlying hormone correlates and analysing the social context of male territorial decisions. Using a lekking population of blackbuck (Antilope cervicapra) as a model system, I took an integrative approach to study the variation in male territorial and mating behaviour on lek.

In the first chapter, I investigated a principal blackbuck lek to understand the fine scale patterns of variation in male territorial investment and test whether they may arise from associated variation in mating benefits. I found that patterns of male investment in lek attendance, signalling and interactions closely track patterns in payoffs, supporting the hypothesis, that due to the large costs of lekking-related behaviour males should tailor their investment in this behaviour to predictable cues of mating benefits. Apart from responding to indirect spatial and temporal cues of potential mating benefits, males also appeared to modulate their lekking behaviour directly in response to a female visiting their territory.

In the second chapter, I examined relationships between lekking behaviour and testosterone and glucocorticoids on a blackbuck lek. I used a non-invasive technique of monitoring endocrine status by measuring concentration of hormone metabolite in blackbuck faeces using enzyme immunoassays. I found that time during the mating season predicted variation in faecal testosterone and cortisol metabolite concentration, but there was no clear relationship between testosterone/cortisol metabolite concentrations with distance from lek-centre.

In the third chapter, I examined the influence of local interactions on male behaviour by quantifying correlation of behaviours at the male neighbourhood level in the short-term (immediate) and long-term (over the mating season). I found that, in the short-term, neighbourhoods show correlated behaviour suggesting that males respond to the behaviour of neighbouring males when making decisions related to displays and how much time to spend on their territory. I found that, over the long-term, lekking male blackbuck appear to locally influence each other’s investment in intensive displays.

Overall my thesis findings indicate that male investment in high-cost signalling is sensitive to diverse factors, including fine-scale spatial and temporal patterns in potential mating benefits, immediate cues of mating benefits, and to social environment. My findings also suggest that taking an integrative approach and examining hormonal mechanisms may provide insights into trade-offs generating variation in costly male behaviour.

Intense competition among individuals of the same sex and species can result in striking, elaborate and costly traits. Such intrasexual competition has been widely studied among males; but it is only in the last few years that intrasexual competition among females has received attention. Recent reviews suggest that competition between females may be widespread; females may compete over a variety of resources including mates, food, nesting sites and safety; and such competition can have important behavioural and evolutionary consequences. However, systematic studies of intrasexual competition among females are scarce. Consequently, our understanding of the form that competition takes in females and the traits that evolve under such competition is limited. Owing to differences in life histories, the patterns and processes acting in female-female competition are expected to be different from those in males. In my thesis, I have focused on studying traits and strategies in intrasexual competition in females in a polygynous species, the tropical rock agama (Psammophilus dorsalis), through observations and experiments in the wild.
The social system plays an important role in establishing the contexts in which various behaviours are played out. Establishing the social system of a population is essential for investigating the ecology and evolution of behavioural and life history traits. Thus, first, I studied the nature of between- and within- sex interactions across the lifetime of individuals in Peninsular rock agama using space use patterns. Individually tagged wild males and females were closely monitored and their home ranges estimated. Male home ranges overlapped multiple female home ranges, but females defended exclusive home ranges, suggesting strong competition.
I then examined signalling traits, which, observations on males suggest, play a key role in conveying information both in direct contest competition and in indirect competition to attract mates. I observed wild individuals every month across their lifetime to study the extent of female signalling and to understand the contexts in which the different signals are used. I also examined whether signalling rates are correlated with proxies of female fitness. I report that females, too, have a complex signalling repertoire. My findings suggest that females may signal both in direct competition in sexual and non-sexual context and to attract mates.
Finally, I examined strategies of female-female competition. Because of their investment in young, the costs of overt competition, such as conspicuous signalling and physical aggression, are expected to be comparatively high for females. Therefore, females should normally signal using relatively inconspicuous traits. They should be sensitive to the perceived threat, more so than males, and escalate to costly signalling and aggression only when the threat is high. I tested this hypothesis using field experiments and by simulating intruder threat on territories of wild female P. dorsalis. I report that in the normal signalling context, females signal using less conspicuous signals, less conspicuous than in males. I also show that females strikingly increase response in the form of signalling and aggression with increasing level of intruder threat. To summarize, I find substantial intrasexual competition in females of a polygynous species. Traits and strategies can be complex and different from that of males. Finally, owing to the cryptic nature of competition, an experimental approach might be key in studying competition between females.

Terrestrial bioacoustics, like many other domains, has recently
witnessed some transformative results from the application of deep
learning and big data (Stowell 2017, Mac Aodha et al. 2018, Fairbrass et
al. 2018, Mercado III and Sturdy 2017). Generalising over specific
projects, which bioacoustic tasks can we consider "solved"? What can we
expect in the near future, and what remains hard to do? What does a
bioacoustician need to understand about deep learning? I will address
these questions, giving a concise summary of recent developments and
ways forward. We build on recent projects and evaluation campaigns led
by the author (Stowell et al. 2015, Stowell et al. 2018), as well as
broader developments in signal processing, machine learning and
bioacoustic applications of these. We will discuss which type of deep
learning networks are appropriate for audio data, how to address
zoological/ecological applications which often have few available data,
and issues in integrating deep learning predictions with existing
workflows in statistical ecology.

Colors in Nature can be produced either chemically, by the selective light absorption by pigments, or physically, by light interference from biophotonic nanostructures. Intriguingly, there are almost no known violet, blue or green pigments in animals. And yet these structurally produced colors are ubiquitous in nature and constitute an important aspect of the overall appearance of organisms, as they are frequently used in camouflage, and in social and sexual communication. As the underlying biophotonic nanostructures are overwhelmingly diverse in form and function, their structural and optical characterization has hitherto remained challenging despite centuries of research, which is where I have made rapid and significant contributions. Although there is a burgeoning interest on structural colors from biologists, physicists and engineers, we currently lack an explicit comparative framework, which is essential to understand how these biological signals function, and evolve in organisms. Moreover, the mechanisms controlling the morphogenesis of these complex, biologically patterned nanostructures are much too large to be described by conventional cell or molecular biology, and much too small to be captured by traditional developmental biology. As a consequence, we know very little about the development of photonic nanostructures within cells, beyond the realisation that they are self-assembled intra-cellularly by mechanobiological, phase separation and micro-phase separation like processes. Biophotonic nanostructures are also of broader interest to materials science and engineering, since the facile synthetic fabrication of three-dimensional photonic nanostructures at these rather large optical length scales (200-500 nm) is challenging. Organismal structural colors that have evolved over millions of years to function in a variety of signalling contexts are an ideal source to look for naturally optimized solutions to technological problems in sensing, photonics, etc. In this talk, I will summarise our current knowledge about the structure, function and morphogenesis of biophotonic nanostructures and how this can be leveraged for the biomimetic or bio-inspired synthesis of next generation photonic meta-materials and devices.

In this talk, I will give an introduction to Topological Data Analysis (TDA), which uses techniques in Topology to uncover hidden patterns in data cloud. At the heart of TDA lies the philosophy that data has a shape, and shape carries meaning. In other words, data cloud can be thought of as points distributed over a smooth manifold. TDA focuses on understanding the shape of the manifold by suitably projecting the data to two dimensions.

I will focus on certain case studies and talk about the merits of TDA in gaining a qualitative understanding of data.

These workshops are intended to serve as an introduction/refresher to commonly used advanced statistical models. The workshops will consist of lectures on how the different statistical models work, accompanied by hands-on sessions in R, where we apply these models to ecological data-sets and become familiar with fitting and interpreting them.
The detailed schedule for the workshops is available here:
https://docs.google.com/document/d/1h6dCLtXBxTRhVi4_MV-3VOLTREP9AcRa81of...

Topic 1: Generalised Linear Models (GLM)

10th January (Friday) 10am - 1pm: Discrete data problems - Prof Nagaraja

13th January (Monday) 10am - 1pm: GLMs with examples of binary and proportion data - Prof. Nagaraja

14th January (Tuesday) 10am - 1pm: R Session: Applying GLMs to ecological data sets - Kavita

(15th Jan 2020 is a HOLIDAY)

16th January (Thursday) 10am - 1 pm: GLMs with examples of count data - Prof. Nagaraja

17th Jan (Friday) 10am - 1pm: R Session: Applying GLMs to ecological data sets - Kavita

Topic 2: Mixed-effects Models

27th Jan (Monday): 10am - 1pm: GLM With examples of zero inflation + R session (by Prof Nagaraja)

28th Jan (Tuesday): 10am - 1pm: Linear mixed-effects models - Prof. Nagaraja

29th Jan (Wednesday): 10am - 1pm: R Session: Applying LMMs to ecological data sets - Kavita

30th Jan (Thursday): 10am - 1pm: 11th Jan 10am - 1pm: Generalised Linear Mixed-effects Models GLMMs - Prof. Nagaraja

31st Jan (Friday): 10 am - 1pm: R Session: Applying GLMMs to ecological data sets - Kavita

*Attendance only with Registration.
**Pre-requisites: Since these workshops focus on advanced statistical models, familiarity with basic statistics (statistical hypothesis testing, one and two-sample problems, simple linear regression, one-way ANOVA) and basic math and probability (functions, distributions) is expected. Since we will be working in R/RStudio, some familiarity with R & R-studio is also expected.