Research Interest
I have been trained extensively in ecological modelling during my M.Sc. study period under the supervision of Prof. Santanu Ray (now retired), Systems Ecology and Ecological Modelling Lab, Department of Zoology, Visva-Bharati University. Since then I work on modelling the dynamics of various population, communities, and systems. After joining Prof. Sabyasachi Bhattacharya's Lab at Agricultural and Ecological Research Unit, Indian Statistical institute, I started working on behavioral ecology and its effect on population growth and spatial distribution pattern. In these research works, I have used a range of test bed populations from blue-tailed bee-eater (in my doctoral thesis), African wild-dogs (collaborative research with Mr. Selim Reja) to cell population (collaborative research with Ms. Trina Roy). The three key research interests
Behavioral ecology
How an individual responds to a stimuli by their internal and external environment defines the behavior of the individual. The collective behaviors of individuals of a population may behave differently to the environment than it would as an individual. My main research interest lies within this collective behaviors. My research output concerns how these collective behaviors can alter the population dynamics and sustainability. Among all the collective behaviors that may occur within a population, I have worked on the following behaviors during my doctoral study.
Cooperation
Sometimes individuals of a population cooperate among themselves by sharing resources and other conditions for growth. These conditions and resources may be food, parental care, and anti-predatory behaviors in the case of ecological populations. Or they may be growth-inducing signals, metabolic regulators, and nutrients in the case of cell populations. In both cases, they are known to facilitate the growth rate. In both cases, there can be different types of cooperators. How different cooperator groups attribute to the different aspects of the population structure, equilibrium densities, and other dynamical properties are my prime research questions. I investigate these questions in both ecological and evolutionary light.
For example, cooperatively breeding birds have two groups of cooperators: sibling birds who are reproductively immature, and reproductively mature subordinates. We found through theoretical modelling that cooperation from the siblings namely primary helpers can alter the social structure of the population but cooperation from the mature subordinates cannot.
Similarly, cell-cell cooperation can determine the proliferation rate of cells under external stresses such as antibiotic treatments. The sharing of negative feedback or suppressor signals due to antibiotics also regulates the maximum cell density that may sustain over time under disturbances. The cells can only overcome their shared suppression in growth by acquiring a minimum threshold size for sustainability.
Migration
Migration is the fundamental way to introduce a population to a habitat. It is the only way to sustain the population in the habitat apart from reproduction. Therefore the migratory paths and behaviors are also important to study for the prediction of dynamics, stability, and spatial distribution of a population. The causes of migration are changes in niches of the migratory species. I investigate the shifts and expansions of these niches following a changing pattern of seasonal migration. My research involves both static and dynamic modelling approaches to investigate migratory pattern. Static modelling framework predicts the qualitative comparisons of migration routes of birds and their prey communities and their changing pattern due to climate change and anthropogenic effects. The dynamic modelling framework predicts the occurrence probability over time for given sites under the same climatic changes and anthropogenic disturbances.
For example, Merops philippinus a long-distance migratory bird has four habitat zones. The zonations inform us about the birds' seasonal occurrences and behavior-based habitat choices. The IUCN provided habitat ranges do not account for the migratory direction-based habitat ranges. Therefore, their map has only one passageway for both immigration and emigration. In my doctoral thesis, I reconstructed their migratory passageways through environmental niche modeling. The new reconstructed niches shows birds immigrates and emigrates via two different passageways.
Merops philippinus and many other migratory birds are asynchronous migrants. These birds reproduces throughout the breeding season in different sites. The departure of some colony then may vary over a long duration. I have found a pattern of the monthly occurrence of these migrants over the different months in my doctoral thesis. The numbers corresponding to the colors
Competition
Limiting resources force individuals of the same or different species to compete against each other. I predict the tolerance level of competition for the sustainability and dynamics of population and community. The competition between prey populations to avoid predation makes the community dynamics more interesting. Often a predator has a favorite prey regardless of prey abundance. I identify the preferred prey species through field study and index them statistically. Then, with these preference indices, I proceed to a dynamic modelling framework for the prediction of predator population and prey community dynamics. So far I have used Merops philippinus and its preys as the test beds for this study at the community level. Otherwise, I have used cells in vitro as test bed at the population level to study the competition as a regulator of population dynamics.
But what happens if the limiting resource itself varies over time? This question leads me to study competition under variable resources. Also, another interesting aspect of this study is that the competition may be observed between even two cooperative groups/ populations. This is an ongoing investigation right now using the avian society of Merops philippinus and its prey species.
Reproduction
Reproduction involves three stages in a eusocial population: nesting, mating, and raising the offspring. There is a chance of failure in each of these stages. I identify the environmental conditions required for each stage of reproductive success of birds, predict the spatio-temporal distribution of the identified environmental condition, and finally provide successful nesting sites for conservation purposes.
The following map shows the estimated spatial distribution of successful nesting sites of Merops philippinus built during my doctoral study. These sites experience at least a 0.5 probability of success at each stage.
Click here to find read my recent publication on Reproductive success.
Eco-physiological response
Physiological response to the environment is similar to animal behavior. The environment signals and the body responds by altering homeostatic conditions and growth rates. If we focus on the responses of the brain, the study concerns behavioral aspects. If we focus on the responses of other organs, metabolism, or body growth, the study concerns physiological responses. Therefore modelling animal behavior and physiological response follow the same growth properties from a holistic point of view. I work on developing growth models that can represent both behavioral dynamics and physiological responses through various parameters of the model.
Please check out the following article from my collaborative work with Mrs. Trina Roy under Prof. Bhattacharyas' supervision on this topic.
Epidemiology and Conservation management
Wild animals often face diseases fatal to their populations. These diseases spread from animal to animal upon migration between habitat patches. Mass vaccination of these wild animals is not always feasible. So designing a control strategy for the epidemics in the wild animals should be through natural paths of the disease, like migration barriers, group augmentations, and interspecific interactions.
Reintroduction of wild populations, captive breeding, and vaccinations can add up to these control strategies to aid further conservation.
Please check out the following article resulting from my collaboration with Mr. Selim Reja and others on the canine distemper epidemic and management strategy in the wild dog population.