The nest of social insects is considered the locus of their social lives. Although several ants and honeybees show site specific task performance; paper wasps usually are devoid of well-defined sites for task performance on their nest. It would be exciting to investigate thus, how and why wasps would organize themselves spatially on their nests in order to fulfill their reproductive and/ or non-reproductive motivations. Each female on the nest of Ropalidia marginata has several options at her disposal including 1. abandoning the parent nest and founding another, 2. joining another foundress, 3. waiting patiently to overthrow an existing queen to take over a fully functional colony or 4. gauging the meek chances of salvaging direct fitness throughout her life and retaining a sterile worker status to rely entirely on indirect fitness. In the light of the variety of strategies employed, we expect great variation in the space use patterns of these females. While this expectation was met, several more engaging questions arose.

Foraging strategies of a predator are shaped by numerous ecological variables. One aspect of foraging strategy focuses on an individual’s space use, which could be driven either by resources or group living. However, not many studies have examined how both resources and group living could together contribute to the space use decisions made by a predator. Moreover, in the group-living context, influence of group sizes on an individual’s space use decisions has rarely been studied. The first objective would be to address these research gaps using the group-living bat species, Megaderma spasma as a model organism.
On a smaller spatial and temporal scale, foraging strategy of a predator could be determined by the distribution and detectability of its prey resources. Previous studies have shown that predators are attracted towards prey aggregates due to increased detectability but their capture success in aggregates might reduce due to the confusion effect. Most studies have examined such predator behaviour in the visual and not in the auditory context. My second objective would be to address this research gap using the bat species, Megaderma spasma as a model organism since they can use both echolocation and prey-generated sounds to capture their prey.

Both intraspecific and heterospecific animal groups are common in nature. Heterospecific animal groups allow individuals to be similar to group members so as to avail the benefits of group living but be dissimilar enough to avoid competition. Mixed-species flocks of birds are one of the most common heterospecific associations in different regions of the world. My aim is to determine how mixed-species flocks assemble and how interactions within these affect participation of flock members. Although similar species tend to associate more with each other in flocks in general, large flocks are often composed of species that are very different from each other. Moreover, some species in mixed-species flocks are important for benefit provision and maintenance of the flock – known as nuclear species. Intraspecifically gregarious species are very often nuclear species in flocks and are also known to be the main benefit providers in flocks. Some other species, although attractive to flock participants, may impose costs on flock participatnts by stealing food found by them (eg. the greater racket-tailed drongo *Dicrurus paradiseus*). We aim to study each of these functional types to understand what traits make them attractive to other species and what factors influence their presence in flocks.
My specific objectives are: 1) To understand the process of formation of mixed-species flocks by examining the changes in flock composition at different stages in flock formation. 2) To understand what traits of intraspecifically gregarious species predict their importance in mixed-species bird flocks. 3) By using the greater racket-tailed drongo as a model for species that impose costs on flock participants, I aim to understand what flock features influence the drongo’s behaviour (whether to steal or forage independently) and what influences the participation of species which are common targets of the drongo in mixed-species flocks.
My study site is Anshi National Park situated in the Uttara Kannada district of Karnataka. I will use a combination of primary and secondary data to address the different objectives in this study.

Ecosystem resilience is defined as the ability of the system to remain
unchanged or regain its prior state after subjected to perturbations. In
this study, we have considered two kinds of perturbations namely; climate
factors and above-ground trophic interactions. As plants form a bridge
between above-ground and below-ground trophic interactions, plants are
considered as an assay to evaluate the status of an ecosystem. In the
current scenario of global warming, the temperature and precipitation
patterns have shown increasing variation, with a shift in mean global
temperature and precipitation patterns. Researchers have documented
increase in temperature and changes in precipitation patterns in
Trans-Himalayan region. Thus Trans-Himalaya is a model ecosystem to
examine vegetation-climate relationships. We hypothesize changes in
phenology considering plant-soil interactions, with the background of
on-going climatic changes in the Trans-Himalayan landscape. In this study,
phenology is used to understand the vegetation state. Phenological changes
can be detected by examining time series data on vegetation. Hence remote
sensing data is used to understand large scale vegetation changes due to
climatic conditions in Trans-Himalayan landscape. Our preliminary analysis
shows that the majority of the area of Trans-Himalayas has not changed
from 2002-2015. We address this resilience of the Trans-Himalayan
vegetation to climatic variations through resource co-limitation
hypothesis.
Above-ground trophic interactions like herbivory and carnivory can have
direct (consumption) and indirect (non-consumption) effects on vegetation.
These above-ground trophic interactions determine the chemical composition
and quantity of detritus. The nutrient in the detritus is recycled back to
plants by soil microbes, and this ecosystem process depends on the abiotic
conditions like soil temperature and moisture. Hence it is important to
understand the interaction between climate factors and above-ground
interactions in determining vegetation structure and composition. The
interactions between above-ground organisms and plants are highly complex.
Trophic cascade provides a framework to understand these complex
interactions. We apply the concept of trophic cascade by conducting
herbivore, carnivore exclusion experiments in grassland ecosystem. These
field experimental plots are set-up across a gradient of rainfall to
capture the interactions between above ground interactions and water
availability. Here I present preliminary results of grass biomass
subjected to different scenarios of above ground trophic interactions.

Tropical habitats face a diverse range of threats. Two common and important threats are invasive species and roads. Invasive plants are proposed to be a major threat to biodiversity worldwide, yet not much is known about their impacts on higher trophic levels, such as insects. Roads and other linear intrusions such as power lines and railway tracks are another common aspect of human disturbance in natural landscapes, including tropical forests, and are often linked to the spread of invasive plants. I studied impacts of these two important proximate drivers of habitat disturbance, namely invasive plant species and roads, on habitat use of butterflies in a tropical moist deciduous forest in Western Ghats. Invasive plants and roads are expected to modify micro-habitat structure, resources and other aspects of the local ecology of butterflies and thereby influence how they use space (micro-habitats within the larger habitat). Because systematic ecological information on tropical butterflies is comparatively limited, I adopted a multi-species approach. I examined space use responses of butterflies to a gradient in lantana cover in the forest, and to the presence of road. The abundance of different species of butterflies in different micro-habitats was taken as a measure of habitat use. Data was collected over two seasons and at two spatial scales. The two habitat disturbances were found to influence local habitat use by butterflies. But, interestingly, species appeared to respond differently, with some showing positive, others negative and some no strong association with road edge or lantana gradient. I then examined whether this variation in response could be understood in terms of species-specific functional traits. Correlating the responses of species to a habitat disturbance with functional traits may provide a way of arriving at general patterns and increasing the ability of studies to predict responses. Species with similar trait values are expected to respond similarly to a habitat change driver. I measured morphological traits in 254 butterfly species from India and classified them according to their micro-habitat preferences (based on expert opinion). I first examined relationships between morphological traits, ecology and evolutionary relatedness. I then examined patterns of correlation between these traits and responses to the two habitat disturbances and found that certain traits can help predict responses. Overall, my study suggests that butterfly space use is influenced by roads and lantana but the response varies across species. These changes in habitat use might have further population or community level consequences that need to be examined.

Bees and wasps are central-place foragers which return to their nest after extended
foraging or hunting trips. When they leave the nest for the first time, they perform
structurally elaborate learning flights to memorise the visual features of the
surrounding environment for guidance on their return. They are also known to perform
learning flights at newly discovered feeding sites. We study these learning flights
in experiments with the buff-tailed bumblebee, Bombus terrestris L., to understand
what and how insects learn. Because B. terrestris nests in the ground and will
collect nectar from ground vegetation, it is possible to compare the learning
flights acquiring information about the nest and a feeding site in circumstances in
which the visual surroundings of each site are very similar. Differences between
nest and feeder departure flights and learning may be related to the greater need of
bees to remember the precise position of their nest hole than the location of
conspicuous flowers.

Taste and smell have a similar function: detecting chemicals from the external world. Despite this
common functionality, the two systems are designed very differently both at the level of the sensory
receptors and in the way information is mapped into the brain. While olfaction is tuned towards
detecting volatile chemicals from air, the taste system is specialized for detecting non-volatile
molecules through contact. Usually the two systems have been studied separately, under the
assumption that both systems are tuned to detect divergent and non-overlapping ensemble of
molecules. We show through electrophysiology that taste sensilla on the proboscis of Drosophila
detect airborne molecules associated with food like acetic acid, acetone and isoamyl propionate,
as well as compounds known to be aversive to the olfactory system like 1-octen-3-ol (associated
with pathogenic microbes). Behavioral tests like Y-maze assay, 4-arm olfactometer assay and
proboscis extension response show that flies deprived of their olfactory organs are capable of
showing response to acetic acid vapors. However mutant flies lacking taste sensilla (and with
olfactory organs ablated) do not respond to such vapors. This shows that the taste system has the
ability to detect some volatile compounds at close range, raising questions about whether there is
a clear separation between the olfactory and gustatory sensory space, at least in insects.

Climate change could influence many aspects of an organism’s energy budget.
For animals that rely on torpor (short-term hypothermia) to save energy
overnight, increasing night time temperatures could be problematic since
they would limit the degree to which metabolic rate could be lowered. Most
studies on the use of torpor explore how it is affected by decreased
environmental temperatures, and have associated its use with decreased
ambient temperature. Climate change presents a challenge where organisms
face increased, rather than decreased, ambient temperatures. Because torpid
organisms reduce their body temperature and metabolic rates as ambient
temperatures get colder, warming temperatures could reduce the efficiency,
and potentially the use of hypothermia. Here, we first defined new ways of
comparing torpor use across species. We then compared measurements of
torpor in hummingbirds across different natural temperature regimes to
evaluate the possible effects of rising temperatures on energy management.
We found that hummingbirds save an average of 82% of their energy per
hour they used torpor. We also found that temperate birds used torpor
more often at a colder than at a warmer site, supporting our hypothesis
that warming could reduce torpor use. In contrast, tropical hummingbirds at
a slightly warmer site used torpor more often than hummingbirds at a
slightly colder site, suggesting that climate change could affect tropical
and temperate birds differently.

Man-made environmental change is the predominant threat to global biodiversity. Amphibians seem to be particularly sensitive to these changes. In the first part of the talk the author examines, based on examples from the Afrotropics, how anthropogenic activities, such as selective logging, forest fragmentation, agriculture, and hunting, influence amphibian communities (i.e. species and functional diversity) in different forest types and savanna. The second part of the talk focuses on the potential adaptability of particular amphibian species to environmental change, thereby illustrating how limited our knowledge, even concerning European species, still is.

Biodiversity is a multidimensional construct, but it is rarely treated as
such. Most often, we use the single metric of species richness to
quantify biodiversity loss though it is well known that functional,
phylogenetic, and other dimensions of biodiversity can be equally
important. We use structural equation modeling to explore how the loss of
diversity in multiple dimensions provides novel insights into the way
ecosystems function. We provide three examples; (1) the consequences of
herbivory on understory vegetation in a hardwood forest, (2) the
consequences of nitrogen enrichment on arctic tundra vegetation, and (3)
the consequences of biogeography on the fragility of bird communities in
the Solomon Islands. These studies support the argument that the well
documented, often adverse consequences of biodiversity loss on ecosystem
functions and services are likely to be more complex than prevailing
unidimensional studies have proven.