Statistical estimators, distributions and simple tests.

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From millions of wildebeest herd crossing political borders in Serengeti to minuscule bacterial colony moving across agar gel in a petri-plate, migratory behavior can be seen at all scales. Migration has evolved multiple times independently in many animal groups, such as birds, fish, mammals (including marine mammals and bats), and reptiles (e.g. sea turtles) and insects. The tradeoffs between the costs and benefits for the evolution and sustenance of migration have been studied in detail. Although evolution of migration in most cases is a response to seasonal variation in resources, its occurrence and extent depend on many factors such as physical, geographical, historical and ecological which may facilitate and/or constrain the evolution of long-distance migration. Because migration includes a suite of traits, selection of the migratory character will ultimately cause indirect selection on correlated traits and vice versa, and potentially also on traits that have consequences beyond just migration. Testing such interactions require comparison across taxa at large scales. Lack of sufficient data as well as suitable comparative tools have been a major limiting factor to carry out such studies.
For my PhD thesis I plan to investigate the interplay of different selection pressures in defining the course of evolution of migration for passerine birds with more than 5000 species. For this, I have considered two scenarios. In first scenario, I will investigate the evolution of two traits (migration and group foraging) that are likely to facilitate the evolution of each other. In second scenario both the traits (migration and ornamentation) are under different selection pressures and expected to constrain the evolution of each other. To test both these scenarios I am using phylogenetic comparative approaches. In my first chapter, I will test the robustness of three approaches to phylogenetic comparative methods and ancestral state reconstruction to features of our large data sets. I will use simulations where we know the exact evolutionary trajectory and test inferences based on three methods, APE package in R, Mesquite and BayesTraits. In the second chapter I will examine the evolution of group migration in passerine birds and check if group foraging facilitates the evolution of group migration. In the third chapter, I will focus on the interaction of sexual ornamentation with migration and test if the ornamentations which directly impede migration.

Dynamic evolution of olfactory receptor genes in mammals: Possible link to anatomy and ecology
Yoshihito Niimura

Olfaction, the sense of smell, is essential for the survival of most animals. It is used for foraging, communicating with conspecifics, and recognizing predators. Diverse odor molecules in the environment are detected by olfactory receptors (ORs) expressed in the olfactory epithelium of the nasal cavity. There are ~400 and ~1,100 OR genes in the human and mouse genomes, respectively, constituting the largest multigene family in mammals. Bioinformatic analyses using various genome sequences revealed that the numbers of OR genes vary greatly among species: African elephants have the largest number of functional OR genes ever examined, with ~2,000, while bottlenose dolphins, which have completely lost the olfactory apparatus, retain only ~10.
In my talk, I would like to introduce our recent study on the degeneration of OR genes in primate evolution, since it provides an excellent example of how anatomical/ecological factors affect the OR gene repertoire in each species. I will also briefly mention preliminary results on the OR genes in Asian elephants.

Population history of whales (and elephants) based on individual whole-genome sequences
Takushi Kishida

Speciation in the open ocean has long been studied, but it remains largely elusive how populations of highly mobile animals, such as whales, in such an open environment become reproductively isolated. Baleen whales of the genus Balaenoptera undertake extensive migrations, and there are few obvious barriers that potentially isolate their populations in the open ocean. In this talk, population history of common minke whales B. acutorostrata and Antarctic minke whales B. bonaerensis was inferred based on the whole genome sequence data of an individual, and discuss about speciation of these two species using such recently-developed genomics tools. I will also talk about very preliminary data on the demographic history of Indian elephants and presence of a bottleneck during the last glacial period.

TBA

Venomous and poisonous animals are found distributed throughout the tree of life. While poisonous animals are toxic when their toxins are ingested, venomous animals use specialised apparatuses to inject their toxins in to afflicted animals. In this talk I will provide an overview of venoms and poisons found in the animal kingdom, with a specific focus on three “stories” that showcase how the theme of convergent evolution underpins the fascinating biology related to such animals. Specifically, I will talk about: (i) the convergent evolution of molecular resistance to cardiac glycoside-harbouring poisonous toads, (ii) the evolution of the fangblenny venom system and its relationship with mimicry, and (iii) the coagulopathic activity of snake venoms and how this relates to the medically important, global issue of snakebite.

Leaf beetles occur worldwide; some of them are even economically important pests of agriculture. They raise broad ecological interest because of their host plant preferences and varying modes of life. Their larvae have developed an impressive repertoire of toxins and repellents to defend themselves against predators. Upon attack, the larvae discharge small droplets from specialized glandular reservoirs on their back (e.g. Chrysomelapopuli). The reservoirs represent “bioreactors” performing all late reactions of the toxin-production, starting from plant-derived or de novo synthesized glucosides. The import of the plant-derived glucosides relies on a sophisticated transport system. Physiological studies revealed a functional network of transporters guiding the plant derived glucosides through the larval body into the defensive system. As transporters usually represent trans-membrane proteins, we developed a protocol for the isolation and identification of these proteins from membranes of the defensive system. After cell lysis and differential centrifugation proteins were separated by SDS-page followed by in-gel digestion and nanoLC-HDMSE analysis. From more than 2000 proteins of glandular tissue, bioinformatic criteria revealed several ABC-transporters and candidates from the solute carriers (SLC) that mediate facilitative diffusion of their sub­strates. Expression analysis of these candidate sequences revealed for some of them high expression in the defensive glands compared to other larval tissues. A subsequent lack-of-function screening by using RNAi revealed in particular one ABC-transporter and an SLC2-candidate being involved in the uptake of salicin from hemolymph into the secretory cell. Heterologous expression of these transporters in frog oocytes confirmed salicin as a substrate. A functional model of the transport network in the leaf beetle C. populi has be developed and will be presented.

Strauss, W. Boland, A. Burse. ABC transporter functions as a pacemaker for the sequestration of plant glucosides in leaf beetles. (2013) eLife http://dx.doi.org/ 10.7554/eLife.01096 .

The 90 My-old obligate and mutualistic fig–pollinator wasp system is exploited by parasitic non-pollinating fig wasps that are fig-species specific and oviposit into their hosts from the exterior of the fig which serves as a wasp nursery. Using Ficus racemosa as the study system, we investigated the underlying mechanisms employed by parasitic wasps to locate hidden hosts, where only cues from the exterior surface or from the interior of the fig could guide this search. We also determined the preference of different parasitic wasps for oviposition sites and hosts within the fig. We show, for the first time, that the fig wasp ovipositor is an olfactory sensor that responds to host volatiles and gaseous CO2.
This sensor could be used by the parasitic wasps to evaluate ecologically relevant cues for oviposition. Chemical footprints left by previously ovipositing wasps also influenced oviposition choice. We found that physiological factors such as ageing and egg load greatly influenced oviposition behavior. These findings reveal the different ways in which parasitic wasps exploit their hosts but also have bearing on the survival of a plant–pollinator mutualism in such a complex and multiply-parasitized system.

Space observation is acknowledged as quintessential for providing reliable monitoring strategies for vegetation at multiple scales over extensive territories with a low population and limited accessibility. Optical satellite imagery represents the major source of data and covers an ample continuum of image resolution and swath. Yet vegetation monitoring in both the dry and wet tropics has long been hampered by insufficient pixel resolution that renders the well-mastered, pixel-wise classification techniques inefficient. The increasing availability of images with high spatial resolution (HSR, pixels of 10 m or less) to very high spatial resolution (VHSR, pixels of less than 2 m) has opened up new prospects by allowing the inference of vegetation properties from image texture features (i.e., inter-pixel variability with respect to distance). In the present talk, we aim to illustrate this potential through published case studies dealing with semiarid vegetation monitoring and baseline above ground biomass assessment in moist tropical forests. In both cases, we applied variants of a method called FOTO (Fourier-based textural ordination) to obtain textural features from the images and relate them to meaningful vegetation properties, such as patterns of vegetation vs. bare ground in drylands, or crown and gap size distribution in forest canopy images. Textural ordination based on Fourier spectra provides a powerful and consistent framework for identifying prominent scales of landscape patterns and comparing scaling properties across landscapes. In the case of forest landscapes, texture features relate to crown size distribution and sometimes to inter-crown gaps and therefore are often good predictors of stand structure and biomass. We also use the radiative transfer model DART as to generate canopy images from three-dimensional forest stand mockups parametrized from pantropical field plots. Simulated canopy images allowed us testing the relevance of texture approaches to retrieve stand characteristics and to explore the complementary with FOTO of features provided by Gabor and continuous wavelet transforms.

Keywords: above ground biomass, canopy grain, FOTO method, patterned semiarid vegetation, tropical moist and wet forest, continuous wavelet transform