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What Noseleaves Do for FM Bats Depends on Their Degree of Sensorial Specialization

Smithsonian Libraries
Background: Many bats vocalizing through their nose carry a prominent noseleaf that is involved in shaping the emission beam of these animals. To our knowledge, the exact role of these appendages has not been thoroughly investigated as for no single species both the hearing and the emission spatial sensitivities have been obtained. In this paper, we set out to evaluate the complete spatial sensitivity of two species of New World leaf-nosed bats: Micronycteris microtis and Phyllostomus discolor. From an ecological point of view, these species are interesting as they belong to the same family (Phyllostomidae) and their noseleaves are morphologically similar. They differ vastly in the niche they occupy. Comparing these species allows us to relate differences in function of the noseleaf to the ecological background of bat species. Methodology/Principal Findings: We simulate the spatial sensitivity of both the hearing and the emission subsystems of two species, M. microtis and P. discolor. This technique allows us to evaluate the respective roles played by the noseleaf in the echolocation system of these species. We find that the noseleaf of M. microtis focuses the radiated energy better and yields better control over the emission beam. Conclusions: From the evidence presented we conclude that the noseleaves serve quantitatively different functions for different bats. The main function of the noseleaf is to serve as an energy focusing mechanism that increases the difference between the reflected energy from objects in the focal area and objects in the periphery. However, despite the gross morphological similarities between the noseleaves of the two Phyllostomid species they focus the energy to a different extent, a capability that can be linked to the different ecological niches occupied by the two species.

The history of dinosaur collecting in central India, 1828-1947

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The history of dinosaur collecting in central India (former Central Provinces and Central India Agency) began in 1828 when W. H. Sleeman discovered isolated sauropod caudal vertebrae in the Lameta Formation near Jabalpur. Subsequently, the area became a focal point for fossil collection, leading to a series of further discoveries that continues today. The earliest discoveries were made by numerous collectors for whom palaeontology was a secondary pursuit, and who were employed in the armed forces (W. H. Sleeman and W. T. Nicolls), medicine (G. G. Spilsbury) or as geologists (T. Oldham, H. B. Medlicott, T. W. H. Hughes and C. A. Matley). Most of their finds were concentrated around Jabalpur or farther south near Pisdura and often consisted of isolated, surface-collected bones. Charles Matley undertook the two most extensive collecting efforts, in 1917-1919 and 1932-1933 (Percy Sladen Trust Expedition). As a result he discovered significant deposits of dinosaurs on Bara Simla and Chhota Simla, revisited Pisdura, and mapped the Lameta Formation. Many new dinosaur taxa resulted from Matley's studies, which still represent most of the known Lameta Formation dinosaur fauna. Current scientific understanding places these fossils among the Sauropoda (as titanosaurians) and Theropoda (as abelisaurids and noasaurids). Early reports of armoured ornithischians were erroneous; these materials also pertain to sauropods and theropods. Supplementary materialA list of the archival documents in the Natural History Museum, London that were used for this study is available at http://www.geolsoc.org.uk/SUP18418.

Higher parasite richness, abundance and impact in native versus introduced cichlid fishes

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Empirical studies suggest that most exotic species have fewer parasite species in their introduced range relative to their native range. However, it is less clear how, ecologically, the loss of parasite species translates into a measurable advantage for invaders relative to native species in the new community. We compared parasitism at three levels (species richness, abundance and impact) for a pair of native and introduced cichlid fishes which compete for resources in the Panama Canal watershed. The introduced Nile tilapia, Oreochromis niloticus, was infected by a single parasite species from its native range, but shared eight native parasite species with the native Vieja maculicauda. Despite acquiring new parasites in its introduced range, O. niloticus had both lower parasite species richness and lower parasite abundance compared with its native competitor. There was also a significant negative association between parasite load (abundance per individual fish) and host condition for the native fish, but no such association for the invader. The effects of parasites on the native fish varied across sites and types of parasites, suggesting that release from parasites may benefit the invader, but that the magnitude of release may depend upon interactions between the host, parasites, and the environment.

Guild-specific patterns of species richness and host specialization in plant–herbivore food webs from a tropical forest

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1. The extent to which plant2013herbivore feeding interactions are specialized is key to understand the processes maintaining the diversity of both tropical forest plants and their insect herbivores. However, studies documenting the full complexity of tropical plant2013herbivore food webs are lacking. 2. We describe a complex, species-rich plant2013herbivore food web for lowland rain forest in Papua New Guinea, resolving 6818 feeding links between 224 plant species and 1490 herbivore species drawn from 11 distinct feeding guilds. By standardizing sampling intensity and the phylogenetic diversity of focal plants, we are able to make the first rigorous and unbiased comparisons of specificity patterns across feeding guilds. 3. Specificity was highly variable among guilds, spanning almost the full range of theoretically possible values from extreme trophic generalization to monophagy. 4. We identify guilds of herbivores that are most likely to influence the composition of tropical forest vegetation through density-dependent herbivory or apparent competition. 5. We calculate that 251 herbivore species (48 of them unique) are associated with each rain forest tree species in our study site so that the 223C200 tree species coexisting in the lowland rain forest community are involved in 223C50 000 trophic interactions with 223C9600 herbivore species of insects. This is the first estimate of total herbivore and interaction number in a rain forest plant2013herbivore food web. 6. A comprehensive classification of insect herbivores into 24 guilds is proposed, providing a framework for comparative analyses across ecosystems and geographical regions.
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