Environmental diversity constrains learning in Drosophila melanogaster

1. Much is known about how enriched environmental diversity affects ability to learn across the months and years that are the developmental periods of large animals. 2. Less is known about how diversity impacts learning across the minutes and hours during which sensory environments of small foraging animals such as insects may vary dramatically. 3. This study shows that Drosophila melanogaster exposed to a diversity of odour–taste associations over a few minutes subsequently learn standard associative learning tasks poorly. 4. This effect is robust to variation in odours used in all parts of experiments. 5. Findings may have an impact on at least three major research areas in ecology: the relationship between biodiversity and ecosystem functioning; the evolution of floral constancy in pollinators; and the pest‐protective effects of mixed species crops.     

Conservation versus commercial exploitation of seals with special reference to the Harp seal

For the past 15 years at least, government officials, scientists, observers and representatives of the news media have massed each year in the Gulf of St Lawrence, Canada, to witness the killing of Harp seals, Pagophilus groenlandicus , by the commercial sealing industry. This species has become possibly the most studied, the most reported and the most photographed species of wildlife in living memory.
Much of this attention has been directed towards arousing public opinion against the annual seal hunts in the Gulf and in the 'Front' areas of the Northwest Atlantic off the coasts of Labrador and Newfoundland. However, considerable scientific research has been done into the behavioural habits and population dynamics of the Harp seal.
Our present knowledge of this species and the co-operation afforded by the governments of Canada and Norway, enable the Labrador herd of the Harp seal to be used as testing ground for rational herd management based on sound conservation principles. But have we achieved our objective?     

Contribution of subsurface peat to CO2 and CH4 fluxes in a neotropical peatland

Tropical peatlands play an important role in the global carbon cycling but little is known about factors regulating carbon dioxide (CO₂) and methane (CH₄) fluxes from these ecosystems. Here, we test the hypotheses that (i) CO₂ and CH₄ are produced mainly from surface peat and (ii) that the contribution of subsurface peat to net C emissions is governed by substrate availability. To achieve this, in situ and ex situ CO₂ and CH₄ fluxes were determined throughout the peat profiles under three vegetation types along a nutrient gradient in a tropical ombrotrophic peatland in Panama. The peat was also characterized with respect to its organic composition using ¹³C solid state cross‐polarization magic‐angle spinning nuclear magnetic resonance spectroscopy. Deep peat contributed substantially to CO₂ effluxes both with respect to actual in situ and potential ex situ fluxes. CH₄ was produced throughout the peat profile with distinct subsurface peaks, but net emission was limited by oxidation in the surface layers. CO₂ and CH₄ production were strongly substrate‐limited and a large proportion of the variance in their production (30% and 63%, respectively) was related to the quantity of carbohydrates in the peat. Furthermore, CO₂ and CH₄ production differed between vegetation types, suggesting that the quality of plant‐derived carbon inputs is an important driver of trace gas production throughout the peat profile. We conclude that the production of both CO₂ and CH₄ from subsurface peat is a substantial component of the net efflux of these gases, but that gas production through the peat profile is regulated in part by the degree of decomposition of the peat.