ETD at Indian Institute of Science
(529 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.
Mostrando recursos 1 - 7 de 7
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Social Organisation And Cooperation In Genetically Mixed Colonies Of The Primitively Eusocial Wasp, Ropalidia Marginata - Arathi, H S
Altruism in its extreme form is seen in social insects where most individuals give up their own reproduction and work to rear the offspring of their queen. The origin and evolution of such sterile worker castes remains a major unsolved problem in evolutionary biology. Primitively eusocial polistine wasps are an attractive model system for investigating this phenomenon. Ropalidia marginata (Lep.) (Hymenoptera: Vespidae) is one such tropical primitively eusocial wasp, in which new nests are initiated either by a single foundress or by a group of female wasps. Worker behaviour in Ropalidia marginata cannot be satisfactorily explained by the haplodiploidy hypothesis...
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Colony Founding And The Evolution Of Eusociality In Primitively Eusocial Wasp, Ropalidia Marginata - Shakarad, Mallikarjaun
Many animals live in societies of varying degrees of organization. Some individuals in these societies seem to sacrifice their own fitness to increase the fitness of some others. Understanding the forces that mould the evolution of such altruistic behaviour has become a dominant theme in modern evolutionary biology.
Primitively eusocial polistine wasps provide excellent model systems to study the evolution of altruism as they show high degrees of plasticity in their behaviour. Different individuals in the same population pursue different social strategies such as nesting alpne or nesting in groups. When wasps nest in groups, usually only one individual becomes the...
3.
Resource, Use, Culture And Ecological Change: A Case Study Of The Nilgiri Hills Of Southern India - Prabhakar, R
Over the last two decades, there have been increasing concerns about environmental degradation and its consequences on the long-term sustainability of socio-economic systems around the world. The publication of the report of the Club of Rome in 1972, (Meadows et al. 1972) focused on the issue of limits to growth. Since then, there has been a profusion of literature and general models have been developed to address the causes of environmental degradation and the unsustainability of current patterns of growth (Ehrlich and Ehrlich 1970; 1990). Essentially these models used parameters that included population growth, consumption levels and aspects of technology,...
4.
Queens And Their Succerssors : The Story Of Power In The Primitively Eusocial Wasp Ropalidia Marginata - Bhadra, Anindita
Ropalidia marginata is characterized as a primitively eusocial wasp due to the absence of morphological differentiation between the queen and worker castes. Unlike other primitively eusocial wasps, however, the queen in this species is a docile individual, who does not use aggression to regulate worker reproduction, and does not act as the central pacemaker of her colony. However, if the queen dies or is experimentally removed, one of the workers steps up her aggression immensely within minutes, and if the queen is not replaced, she develops her ovaries, reduces aggression and takes over as the new queen of the colony....
5.
The Biology Of Two Sexes : A Study Of The Primitively Eusocial Wasp Ropalidia Marginata - Sen, Ruchira
A striking feature of hymenopterans societies is the absence of male workers. Foraging, nest building, brood care and all other activities required for the functioning of the colony are carried out by the females. These behaviours of the females and the implied cooperation and altruism have led social insect researchers to focus almost exclusively on the female members of hymenopterans societies. As a consequence, males have remained relatively neglected. The imbalance in the attention paid by researchers to females and males has been even more striking in the case of the extensively studied primitively eusocial wasp Rosalinda marginata. I have...
6.
Sensory Ecology Of Acoustic Communication In The Tropical Bushcricket Genus Mecopoda : Mechanisms And Evolution Of Synchrony - Nityananda, Vivek
In this thesis, I characterise five species of the bushcricket genus Mecopoda with respect to their acoustic signals and morphology and investigate the phenomenon of acoustic synchrony in one of these five species: Mecopoda ‘Chirper’. In several bushcricket species, individual males synchronise their chirps during acoustic interactions. Synchrony is imperfect and the chirps of the males lead or follow each other by a short duration of time. Imperfect synchrony is believed to have evolved in response to female preferences for leading chirps. This model of the evolution of acoustic synchrony, however, depends on assumptions about the physiological mechanism of acoustic...
7.
Tree Diameter Growth : Variations And Demographic Niches In A Tropical Dry Forest Of Southern India - Nath, Cheryl D
Tree growth influences forest community dynamics and responses to environmental variations, but currently is not well understood. Tree growth in highly diverse wet tropical forests have been well studied and characterised compared to the species-poor dry tropical forests. Thus, it is not clear if growth rates and community dynamics of dry forests are similar to those of wet forests, given the longer dry season, greater rainfall variability, more open canopy and lower number of species in dry forests. This thesis focuses on identifying important factors that influence tree diameter growth rates in the dry tropical forest at Mudumalai, southern India,...
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