Aposematism increases acoustic diversification and speciation in poison frogs

Multimodal signals facilitate communication with conspecifics during courtship, but they can also alert eavesdropper predators. Hence, signallers face two pressures: enticing partners to mate and avoiding detection by enemies. Undefended organisms with limited escape abilities are expected to minimize predator recognition over mate attraction by limiting or modifying their signalling. Alternatively, organisms with anti-predator mechanisms such as aposematism (i.e. unprofitability signalled by warning cues) might elaborate mating signals as a consequence of reduced predation. We hypothesize that calls diversified in association with aposematism. To test this, we assembled a large acoustic signal database for a diurnal lineage of aposematic and cryptic/non-defended taxa, the poison frogs. First, we showed that aposematic and non-aposematic species share similar extinction rates, and aposematic lineages diversify more and rarely revert to the nonaposematic phenotype. We then characterized mating calls based on morphological (spectral), behavioural/physiological (temporal) and environmental traits. Of these, only spectral and temporal features were associated with aposematism. We propose that with the evolution of antipredator defences, reduced predation facilitated the diversification of vocal signals, which then became elaborated or showy via sexual selection. © 2014 The Author(s) Published by the Royal Society. All rights reserved

Passing the Panda Standard: A TAD Off the Mark?

Tilapia, a tropical freshwater fish native to Africa, is an increasingly important global food commodity. The World Wide Fund for Nature (WWF), a major environmental nongovernmental organization, has established stakeholder dialogues to formulate farm certification standards that promote ‘‘responsible’’ culture practices. As a preface to its ‘‘tilapia aquaculture dialogue,’’ the WWF for Nature commissioned a review of potential certification issues, later published as a peer-reviewed article. This article contends that both the review and the draft certification standards subsequently developed fail to adequately integrate critical factors governing the relative sustainability of tilapia production and thereby miss more significant issues related to resource-use efficiency and the appropriation of ecosystem space and services. This raises a distinct possibility that subsequent certification will promote intensive systems of tilapia production that are far less ecologically benign than existing widely practiced semiintensive alternatives. Given the likely future significance of this emergent standard, it is contended that a more holistic approach to certification is essential

ENVIRONMENTAL AND ECONOMIC COSTS OF VERTEBRATE SPECIES INVASIONS INTO THE UNITED STATES

The more than 50,000 species of plants, animals, and microbes introduced into the United States (US) cause more extinction of native species than most any other threat and cause more than $120 billion in damages and control costs each year. In particular, invasive mammals and birds cause major environmental and economic losses totaling about$46 billion per year in damage and control costs per year. Feral cats, rats, and hogs are especially serious pests. Pigeons and starlings are a major concern in cities and US agriculture. Prevention and management strategies will be discussed

Differences in diet among frogs and lizards coexisting in subtropical forests of Australia

This study investigates predator size and prey type as potential proximal causes of differences among diets of three lizard species (family Scincidae) and three frog species (subfamily Limnodynastinae) that coexist in wet subtropical forest in eastern Australia. Frogs eat smaller prey than lizards having the same gape size and there were significant differences in the types of arthropods eaten by frogs and lizards. Differences among species within frogs and lizards were small and not statistically significant. Frogs ate more amphipods, mites, and ants than the lizards, and lizards ate more termites, millipedes, isopods, and orthopterans than the frogs. Other categories were eaten in similar quantities by both frogs and lizards

La Produccion de Alimentos y la Crisis Energetica

By the year 1975, the world population is expected to reach 4 billion human beings. As the population continues to grow, there will be growing concern about how to prevent or avoid large-scale famine. Concurrently, an energy crisis (caused by fuel shortages and high fuel prices) is expected as the world's population continues  as reserves of the non-renewable resource of fuels are rapidly depleting. The energy crisis is also expected to have a significant impact on production technology,on food production technology in the United States and on the "green revolution"  because both crop production systems depend on large inputs of energySe espera que para el año 1975 la poblacion mundial alcance la cifra de 4 billones de seres humanos. Segun continue creciendo la poblacion crecera la preocupacion sobre como prevenir o evitar una hambruna en gran escala. Concurrentemente se espera una crisis energetica (causada por escasez de combustibles y precios altos de los mismos) al paso que se vayan agotando rapidamente las reservas del recurso no renovable que son los combustibles de origen fosil. Se espera tambien que la crisis energetica tenga un impacto significativo en la tecnologfa de la produccion de alimentos en los Estados Unidos y en la "revolucion verde" porque ambos sistemas de produccion de cosechas dependen de grandes insumos de energia

A framework for reviewing the trade-offs between, renewable energy, food, feed and wood production at a local level

High fuel prices and concerns about energy security and anthropogenic climate change are encouraging a transition towards a low carbon economy. Although energy policy is typically set at a national level, tools are needed for people to engage with energy policy at regional and local levels, and to guide decisions regarding land use, distributed generation and energy supply and demand. The aim of this paper is to develop a per-capita approach to renewable energy demand and supply within a landscape and to illustrate the key trade-offs between renewable energy, food, (animal) feed and wood production. The chosen case study area (16,000 ha) of Marston Vale, England is anticipated to have a population density midway between that for England and the UK. The daily per capita demand for energy for heat (31 kWh), transport (34 kWh) and electricity (15 kWh) when combined (80 kWh) was seven-fold higher than the combined demand for food (2 kWh), animal feed (6 kWh), and wood (4 kWh). Using described algorithms, the combined potential energy supply from domestic wind and photovoltaic panels, solar heating, ground-source heat, and municipal waste was limited (<10 kWh p−1d−1). Additional electricity could be generated from landfill gas and commercial wind turbines, but these have temporal implications. Using a geographical information system and the Yield-SAFE tree and crop yield model, the capacity to supply bioethanol, biodiesel, and biomass, food, feed and wood was calculated and illustrated for three land-use scenarios. These scenarios highlight the limits on meeting energy demands for transport (33%) and heat (53%), even if all of the arable and grassland area was planted to a high yielding crop like wheat. The described framework therefore highlights the major constraints faced in meeting current UK energy demands from land-based renewable energy and the stark choices faced by decision ma