Recursos de colección

ETD at Indian Institute of Science (3.241 recursos)

Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.

Centre for Ecological Sciences (ces)

Mostrando recursos 1 - 20 de 31

  1. Causes and Consequences of Hetrospecific Foraging Associations in Terrestrial Bird Communities

    Sridhar, Hari
    The question of group-living in animals has attracted a lot of research attention. Today, we have a nuanced understanding of ultimate explanations and proximate mechanisms for group-living, as well as the genetic basis for seemingly puzzling aspects of sociality such as altruism. However, our current view of sociality has been obtained almost entirely in an intraspecific context, i.e. based on groups consisting of individuals of a single species. On the other hand, heterospecific sociality, i.e. groups formed by individuals of multiple species, has been largely ignored in group-living theory and empirical research. This is despite the fact that heterospecific sociality...

  2. Systematics, Phylogeny And Acoustic Evolution In Field Crickets (Orthoptera, Grylloidea, Gryllinae)

    Jaiswara, Ranjana
    Since several decades, field crickets of the subfamily Gryllinae under order Orthoptera have been used as a model group by researchers working in the field of neuroethology, behavioural ecology and bioacoustics. Subfamily Gryllinae is a much diversified group and members are diverse in their biological traits however the most commonly used model systems in the research fields belong to only three genera: Gryllus, Teleogryllus and Acheta. All the three genera are related to each other therefore, they fail to represent the wide diversity of ecological and behavioral traits that are encompassed by other members of Gryllinae. To understand the diversity...

  3. Queen Succession in the Primitively Eusocial Wasp Ropalidia Marginata

    Saha, Paromita
    Social insects are the most dominant terrestrial fauna for the last 50 million years. This tremendous ecological success is accompanied by the fact that sociality has evolved multiple times independently and achieved highest degree of complexity in insect lineages. The remarkable social organization found in insect societies is the result of finely balanced cooperation and conflict among the colony members. A typical hymenopteran colony is characterised by one or a few queens monopolizing reproduction and several sterile workers co-operatively raising brood and performing colony activities. The colonies are often conceptualized as superorganisms where groups of cooperative workers are compared with...

  4. Queen Succession in the Primitively Eusocial Wasp Ropalidia Marginata

    Saha, Paromita
    Social insects are the most dominant terrestrial fauna for the last 50 million years. This tremendous ecological success is accompanied by the fact that sociality has evolved multiple times independently and achieved highest degree of complexity in insect lineages. The remarkable social organization found in insect societies is the result of finely balanced cooperation and conflict among the colony members. A typical hymenopteran colony is characterised by one or a few queens monopolizing reproduction and several sterile workers co-operatively raising brood and performing colony activities. The colonies are often conceptualized as superorganisms where groups of cooperative workers are compared with...

  5. Eco-Hydrology of a Seasonally Dry Tropical Forest : Tree Growth, Belowground Water Dynamics and Drought-Vulnerability

    Tarak, Rutuja Chitra
    Tropical forests are storehouses of more thanhalf of the world‘s biodiversity and play a key role in global carbon, water and energy cycles. However, as a consequence of rapid anthropogenic climate change, biodiversity and climate functions of these forests are under a threat. Climate is changing not only in mean state but its variability is increasing, with extreme events such as droughts, heat waves and storms also rising. Water is fundamental to plants‘ existence, and in the tropics, is a key determinant of plant species‘richness, composition, growth and survival. There is thus an increasing interest in understanding how changing rainfall...

  6. A Farewell to Arms : Dynamics of Interactions between the Unique Semi-myrmecophyte Humboldtia Brunonis (Fabaceae) and its Domatia-inhabitants in the Absence of Universal Protection Mutualism

    Chanam, Joyshree
    Mutualistic interactions between species are balanced on a delicate scale of net benefits to both interacting partners. The dynamics of such interactions could change depending on the context in which these interactions occur. One of the most well-studied models for interspecies mutualisms are myrmecophytic systems, also known as ant-plant systems, where the host plant (myrmecophyte) provides shelter (domatia), solely or along with food resources, for ant partners, while the domatia-resident ants intensively patrol and protect the host plant from herbivory. In some cases, nutrient flux has also been reported from the ant-derived debris in the domatia to the host plant....

  7. A Farewell to Arms : Dynamics of Interactions between the Unique Semi-myrmecophyte Humboldtia Brunonis (Fabaceae) and its Domatia-inhabitants in the Absence of Universal Protection Mutualism

    Chanam, Joyshree
    Mutualistic interactions between species are balanced on a delicate scale of net benefits to both interacting partners. The dynamics of such interactions could change depending on the context in which these interactions occur. One of the most well-studied models for interspecies mutualisms are myrmecophytic systems, also known as ant-plant systems, where the host plant (myrmecophyte) provides shelter (domatia), solely or along with food resources, for ant partners, while the domatia-resident ants intensively patrol and protect the host plant from herbivory. In some cases, nutrient flux has also been reported from the ant-derived debris in the domatia to the host plant....

  8. Modelling Spatial Patterns of Landsacape Dynamics

    Aithal, Bharath H
    Landscape is a heterogeneous collection of visibly distinct features of various elements of land and its various forms on the earth surface. Its pattern is subjected to disturbances and undergo rapid alterations in its grain sizes. The evolving patterns of landscape define and decide various parameters for the planning and management of resources. These dynamic systems possess both spatial and temporal complexity. Exploitation of natural resources and drastic land cover changes have given rise to significant impacts on ecosystem structure and dynamics. The functional abilities (bio-geo chemical cycling, hydrological cycling, etc.) of the landscape are basically dependent on the structure...

  9. Fire Ecology of a Seasonally Dry Tropical Forest in Southern India

    Mondal, Nandita
    Fire ecology encompasses the study of the factors, biotic and abiotic, that influence the occurrence of fire in an area, as well as the effects fire has on the flora and fauna native and non-native to the region (Whelan 1995). Fire has had a major influence on shaping biomes as we see them today. Fire has had an effect on vegetation much before the evolution of Homo on Earth (Keeley and Rundel 2005, Pausas and Keeley 2009, Midgley and Bond 2011). With the evolution and expansion of Homo across Earth, fire has been tamed, and then generated and used over...

  10. Fire Ecology of a Seasonally Dry Tropical Forest in Southern India

    Mondal, Nandita
    Fire ecology encompasses the study of the factors, biotic and abiotic, that influence the occurrence of fire in an area, as well as the effects fire has on the flora and fauna native and non-native to the region (Whelan 1995). Fire has had a major influence on shaping biomes as we see them today. Fire has had an effect on vegetation much before the evolution of Homo on Earth (Keeley and Rundel 2005, Pausas and Keeley 2009, Midgley and Bond 2011). With the evolution and expansion of Homo across Earth, fire has been tamed, and then generated and used over...

  11. Insights into an Evolutionary Radiation : Causes And Consequences of Diversification in the Western Ghats Bush Frogs

    Vijayakumar, S P
    One of the biggest attractions of the tropics is its stunning diversity; the origin and determinants of this diversity are amongst the most important questions in evolution and biogeography. There are two ways of looking at diversity: diversity as observed in clades on the tree of life and diversity as distributed in space. Various processes drive patterns in clades leading to a gradient of evolutionary radiations. These radiations are amongst the major contributors to Earth's biological diversity and act as good model systems to test the relative significance of processes governing macroevolutionary patterns of diversification. My research presented here revolves...

  12. Acoustic Signals, Mate Choice And Mate Sampling Strategies in a Field Cricket

    Nandi, Diptarup
    Acoustic communication in orthopterans and anurans provides a suitable model system for studying the evolutionary mechanisms of sexual selection mainly because males use acoustic signals to attract females over long distances for pair formation. Females use these signals not only to localize conspecific males but also to discriminate between potential mates. Investigations on the effect of sexual selection on acoustic signals requires an understanding of how female preferences for different features of the acoustic signal affect male mating success under ecological constraints in wild populations. The effect of female preferences on male mating success depends on the mate sampling strategy...

  13. Investigating Pattern Recognition And Bi-coordinate Sound Localization in the Tree Cricket Species Oecanthus Henryi

    Bhattacharya, Monisha
    Acoustic communication, used by a wide variety of animals, consists of the signaler, the signal and the receiver. A change in the behaviour of the receiver after reception of the signal is a prerequisite for communication. A response to the signal by the receiver depends on signal recognition and localization of the signal source. These two aspects, namely recognition and localization by the receiver, form the main body of my work. In the mating system of crickets, the males produce advertisement calls to attract silent females to mate. Females need to recognize the conspecific call and localize the male. The...

  14. The Structure And Function Of The Vocal Repertoire Of The Greater Racket-Tailed Drongo (Dicrurus paradiseus) : Insights Into Avian Vocal Mimicry

    Agnihotri, Samira
    Sound is used as a medium for communication by taxa as varied as insects, fish, amphibians, birds and mammals. In some birds like the suboscines, song is genetically encoded, whereas in parrots, hummingbirds and oscines, it is learnt. The diversity and plasticity of birdsong continues to generate interest amongst ornithologists, and many questions remain unresolved. For instance, why do some species sing hundreds of different songs while others use simple, stereotyped ones for the same purposes? Why do some birds learn not only their own species’ song, but also the songs of heterospecifics? There are several anecdotal reports of such...

  15. Mate Choice, Mate Sampling And Baffling Behaviour In The Tree Cricket Oecanthus henryi

    Deb, Rittik
    Among the different sensory modalities that play a role in sexual selection, acoustic communication plays an important one. Acoustic communication has been known to be used for male-male competition (territory maintenance, male aggression during mating),for advertisement to the opposite sex (mating status, body condition, genetic quality, nutritional status) and used by females to sample and choose conspecific preferred males. The use of acoustic communication for sexual display and information exchange has been extensively studied in multiple taxa, including insects, anurans, birds and mammals. Among insects, crickets have proven to be good model systems to study sexual selection based on acoustic communication as most species have...

  16. Mate Choice, Mate Sampling And Baffling Behaviour In The Tree Cricket Oecanthus henryi

    Deb, Rittik
    Among the different sensory modalities that play a role in sexual selection, acoustic communication plays an important one. Acoustic communication has been known to be used for male-male competition (territory maintenance, male aggression during mating),for advertisement to the opposite sex (mating status, body condition, genetic quality, nutritional status) and used by females to sample and choose conspecific preferred males. The use of acoustic communication for sexual display and information exchange has been extensively studied in multiple taxa, including insects, anurans, birds and mammals. Among insects, crickets have proven to be good model systems to study sexual selection based on acoustic communication as most species have...

  17. Sexual Selection On Elephant Tusks

    Chelliah, Karpagam
    Darwin was troubled by elaborate male traits observed in many species that are seemingly maladaptive for survival, the peacock’s tail being the most iconic of all. He wrote "The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick" because it challenged his theory of evolution by natural selection for adaptive traits. The extreme length of the tail may render a peacock more vulnerable to predation and therefore maladaptive for survival. To account for the evolution of apparently maladaptive traits he proposed the theory of sexual selection, wherein, traits that directly enhance mating success...

  18. Sexual Selection On Elephant Tusks

    Chelliah, Karpagam
    Darwin was troubled by elaborate male traits observed in many species that are seemingly maladaptive for survival, the peacock’s tail being the most iconic of all. He wrote "The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick" because it challenged his theory of evolution by natural selection for adaptive traits. The extreme length of the tail may render a peacock more vulnerable to predation and therefore maladaptive for survival. To account for the evolution of apparently maladaptive traits he proposed the theory of sexual selection, wherein, traits that directly enhance mating success...

  19. Climate Change Mitigation And Adaptation In Indian Forests

    Chaturvedi, Rajiv Kumar
    Research leading to this thesis aims to assess the policy relevant mitigation potential of Indian forests as well as aims to assess the impact of climate change on carbon stocks, vegetation boundary shifts, Net Primary Productivity (NPP) and the mitigation potential of Indian forests. To project the impact of climate change we chose a dynamic global vegetation model ‘Integrated Biosphere Simulator’ (IBIS V.2.6b4). We selected A2 and B2 scenarios for projecting the impacts. Mitigation potential was assessed using the ‘Generalized Comprehensive Mitigation Assessment Process’ (GCOMAP) model. We assess the mitigation potential of Indian forests in the light of India’s long-term...

  20. Trade-offs And Social Behaviour In The Cellular Slime Moulds

    Sathe, Santosh
    By combining laboratory experiments with field work, I have looked at the following aspects of cellular slime mould (CSM) biology: (a) the genetic structure of social groups (fruiting bodies) in the wild and its relation to the role of large mammals as dispersal agents; (b) social behaviour in clonal, intra-species polyclonal and interspecies social groups and (c) fitness-related trade-offs with respect to life history traits as a possible mechanism for coexistence and cooperative behaviour in CSMs. The major findings of this study are as follows: (a) individuals belonging to different strains of a species, different species and genera occur in...

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