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The first half of the talk will essentially give an overview of game theory. Concepts of non cooperative and cooperative game theory will be illustrated using games and examples. The other part of the talk will present the use of game theory in understanding the competition of High Speed Rail (HSR) and other modes of transportation and their market strategies once HSR enters the market.
Given the economic and ecological values of coastal ecosystems in South East Asia, their preservation represent a tremendous environmental stake. Estuaries, mangroves and coral reefs, for example, provide resources and income for millions of inhabitants in these regions. However these ecosystems are severely threatened by anthropogenic and climatic pressure, which are often closely related. Recent findings have revealed that microbes and their viral parasites are highly abundant and dynamics in coastal waters. We also now know that they can quickly respond to environmental perturbations, and therefore represent excellent indicator of ecosystem health status. Here, we take the emblematic example of coral reefs in which the specific interactions between bacteria and viruses are now strongly suspected, according to the environmental conditions (water quality, temperature, salinity, contaminants, etc.), either to reinforce coral stability or conversely fasten their decline. Ongoing projects conducted in Vietnam aim at further investigating such poorly known mechanisms, which could promote the development of pioneer works for a better protection of marine resources.
Semi-arid ecosystems can exhibit striking vegetation patterns, which may have no characteristic size of patchiness. Elucidating local scale processes that generate these macroscopic patterns is of fundamental ecological importance. In addition, they may provide insights and tools to forecast the future dynamics of these highly vulnerable ecosystems that are prone to abrupt, irreversible shifts in vegetation cover, often resulting in desertification. I ask what information can be inferred from spatial vegetation patterns about an ecosystem and the processes driving it. I approach this question from two related angles. The first is from the context of scale and strength of underlying ecological interactions in a landscape. The second is from the context of regime shifts and spatial indicators of the same.
I begin by reviewing previous work done on bistability in ecosystems and spatial patterns indicative of approaching regime shifts. I briefly discuss the pros and deficiencies of existing spatial early warning signals of abrupt regime shifts (also called,discontinuous transition). I then propose and analyse a new metric, the power spectrum. I demonstrate that in combination with another widely used early warning signal - the probability distribution of vegetation patches in the system, it could provide a robust tool for detection of imminent discontinuous transitions.
The nature of regime-shifts (continuous/discontinuous) is determined by the underlying interactions in the system. Within this framework, I carry out further investigations of spatial patterns and the processes that they are signatures of. Most ecological interactions between species of the same trophic level (such as between different plants) can be simplified into two basic types – competition and facilitation. The relative scales over which interactions of each type are operational, could potentially determine the nature of the spatial patterns observed in vegetation over a landscape. I use cellular automaton models to simulate conditions with different scales of competitive and facilitative interactions in a system and analyse the resultant spatial patterns for signatures of these underlying rules.
The concept of sexual selection has been separated into two main components, male-male competition and female choice. Among these, female choice is probably the best studied and yet most controversial. Crickets are excellent model systems to study female choice due to their elaborate male advertisements, diverse female preferences and classic female-controlled mating. However, though crickets have been studied for a long time, most of these studies are entirely laboratory-based and do not examine female choice based on acoustic cues in the natural ecological context. Hence in my thesis I have tried to address female choice based on acoustic cues using a combination of laboratory and field studies with the tree cricket Oecanthus henryi as a model system. I started by examining male calling song variation and repeatability in the field, a prerequisite for understanding the available features for acoustically-based female choice. Following this I examined female preference for those call features which are reliable indicators of preferred male traits. I also examined the ecological context of female mate sampling to understand what a female actually faces in the field while choosing male traits. For this objective I examined male and female spatial organization, male sound field overlaps and female sampling opportunities. Using the information gathered from these two studies, I examined baffling behaviour in these crickets. Baffling is a unique behavior where males call from self-made holes in a leaf rather than calling from the leaf edge (their natural calling surface) thus increasing their loudness many-fold. I examined the context and advantages of baffling and the factors that may have led to its evolution.
The Elapidae (i.e. Coralsnakes, Cobras, Kraits, Mambas, Taipans and Sea-snakes) are a widely distributed, morphologically diverse, and highly venomous family of snakes whose evolutionary history and origin have been of enormous interest to biologists since the early 20th century. The traditional factor limiting a comprehensive, phylogenetic appraisal of the Elapidae has been the availability of samples of Old World Coralsnakes. Usually small, shy and fossorial, these animals are amongst the rarest venomous Asian snakes and their sampling, especially in molecular studies, has been sparse until now. Equipped with the most complete sampling of Old World Coralsnakes to-date, our research is for the first time investigating aspects of their radiation, including evolutionary relationships, temporal patterns of species diversification, and biogeographic history. Based on an integrative approach using molecular methods, morphology and geometric morphometrics, our results surprisingly suggest a basal phylogenetic position for Indian Coralsnakes and thus raise interesting implications that challenge the current scientific consensus on the early evolutionary history of elapids. The presentation will begin with a brief ‘ode’ to taxonomy and squamates before addressing the speaker’s primary research.
A century ago, our understanding of behavior was dominated by naturalists. Today, we can assess and manipulate nervous systems at genetic, molecular and physiological levels. Despite our tremendous focus on understanding the brain, we still know remarkably little about how even simple brains generate complex behaviors. By studying natural behavior and the processing of natural stimuli across animals, we can unite these modern scientific techniques with natural observations to truly understand how brains make decisions in our complex world.
Our research employs a comparative approach to understand how insect brains parse the complex natural chemical environment to generate decisions. By all accounts, insects are masters of our animal kingdom. In fact, estimates suggest there are 100 times more species of insects than any other animal taxa1. The insect “microbrain” is also capable of incredibly complex decisions using a tractable nervous system. Finally, insects are known for their exquisite olfactory capabilities and use chemicals to locate mates, food, egg-laying sites, and to avoid danger, among others.
Our current research focuses on two major questions: By what mechanisms can nervous systems evolve to generate novel decisions? And second, how do nervous systems adapt to make the same decisions in diverse environments? For the first question, we examine the chemosensory basis for sympatric speciation events in Rhagoletis flies. For the second, we study how similar transcontinental species of hoverflies pollinate in subartic Swedish meadows, the Himalayan mountains, and even South Indian rainforests. We endeavor that our comparisons will allow us to generate overarching principles for decision making constrained by fundamental concepts, rather than specific physiologies.
1. Mora, C., Tittensor, D. P., Adl, S., Simpson, A. G. B. & Worm, B. How many species are there on earth and in the ocean? Plos Biol 9, e1001127 (2011).
Avian malaria parasites (Plasmodium spp.) are prevalent worldwide, but information about their impact on birds, especially during primary infections is insufficient. In the first part of the talk I will overview the results of our recent experimental studies showing parasites development strategies and importance of the parasites to some bird
species; such data is underestimated in field studies. In the second part of the talk I will show the importance of the knowledge of classical biology and will illustrate how such information can be used together with new technologies. First, developing new methods to generate large amounts of purified DNA and working with single cells of pathogenic organisms, which can be separated using laser micro-dissection system. Both methods were developed using avian haemosporidian parasites and could be applied for molecular analysis of various microorganisms.
The third episode examines the spiders and others that produce silk. Attenborough visits New Zealand's Waitomo Caves, which are inhabited by fungus gnats whose illuminated larvae sit atop glistening, beaded filaments to lure their prey. The ability to spin silk developed early in the invertebrates' history, being first used as an adhesive. The female lacewing still applies it in this way, to suspend its eggs from plant stems. Spiders first employed it as a sensitive trip line to detect movement, and Attenborough illustrates this by encouraging a trapdoor spider. The speed with which it appears causes the presenter to jump in surprise. The webs spun by orb-weavers are complex and can comprise up to 60 metres of silk and 3,000 separate attachments. A time-lapse sequence reveals their intricate construction. The largest are made by Nephila and can be several metres across. The venomous redback spins three-dimensionally, and fixes vertical lines that suspend its unlucky meals in mid-air. Meanwhile, the bolas spider swings a length of silk with a sticky blob on the end, with which to snare passing moths. Argiope exemplifies the dangers of mating that are faced by some male spiders: unless they are careful, they can be consumed by the females. The courtship of the wolf spider, though less risky, is one of the more elaborate. Its nesting habits are discussed, along with the eventual birth of its young, which cling to their mother's back.
It is increasingly important from both a theoretical and a practical viewpoint to understand the patterns of biodiversity and ecosystem functioning in agricultural areas, especially in
areas that were cleared from rich tropical rainforest. The Western Ghats of India are one of the richest biodiversity hotspots in the world, yet only 6% of the Ghats remain under original vegetation. Much of the Ghats are planted with coffee – often grown under heavy shade provided by native trees – and tea, which is grown under scant shade provided by exotic trees. Bat species distributions are poorly known from the Western Ghats; no data exists on the response of bats to tea plantations anywhere in the world; and there is little data on how Old World bats respond to coffee plantations.
Bats play important roles in ecosystem functioning. They occupy many different trophic niches, so are likely to show a wide range of responses to habitat degradation and conversion. We
looked at changes in bat species composition from reserve forests to forest fragments, and again from coffee plantations to tea plantations. We assessed the functional diversity of bats retained in various habitats within the modified landscape - using a multiple trait space based approach to functional diversity for the first time in bats - by quantifying a range of traits from
diet to wingspan that affect a species’ ecological role. We also assessed the degree of trait filtering occurring in heavily modified plantation types. Further spatial analyses revealed how bats are using the mosaic landscape under study, and help assess the degree to which further habitat modification could impact different bat species.
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