The number of competitor species is unlinked to sexual dimorphism.

Sexual size dimorphism (SSD) can allow males and females of the same species to specialize on different sized food items and therefore minimize intraspecific competition. Interspecific competition, however, is thought to limit sexual dimorphism, as larger competitors in the community will prevent the larger sex from evolving larger size, and smaller species may prevent the smaller sex from becoming even smaller. We tested this prediction using data on the sexual size dimorphism of lizards, and mammalian carnivores, on islands world-wide. Because insular communities are depauperate, and guilds are species-poor, it is often assumed that enhanced sexual size dimorphism is common on islands. The intensity of interspecific competition, hindering enhanced dimorphism, is thought to increase with competitor richness. We tested whether intraspecific sexual size dimorphism of mammalian carnivores and lizards decreases with increasing island species richness. We further computed the average sexual dimorphism of species on islands and tested whether species-rich islands are inhabited by relatively monomorphic species. Within families and guilds across carnivores and lizards, and with both intraspecific and interspecific approaches, we consistently failed to find support for the notion that species-poor islands harbour more sexually dimorphic individuals or species. We conclude that either interspecific competition does not affect the sexual size dimorphism of insular lizards and carnivores (i.e. character displacement and species sorting are rare in these taxa), or that the number of species in an assemblage or guild is a poor proxy for the intensity of interspecific competition in insular assemblages.

Wineries Evaluation of Costs and Benefits of Sustainability Certification Program: The Case of Terra Vitis in France.

BACKGROUND: The current paper analyses the evaluation of the costs and benefits of French wineries (N=69) participating in the sustainability program Terra Vitis, a widespread environmental certification scheme within the French wine industry. METHOD: An online questionnaire was sent to all Terra Vitis participants, in order to analyse the evaluation of economic costs and benefits (together with environmental benefits) as perceived by wineries. RESULTS: Our findings reveal that older participants in the scheme (over 5 years), firms with higher export share (>40% of annual turnover) and cooperative wineries tend to be keener to assign a positive evaluation to the benefits/costs ratio in both the vineyard and the winery. CONCLUSION: In the context of increasing concerns regarding the economic and environmental performance of the French agricultural sector, such findings and also the patent research could be useful for policy makers and entrepreneurs in defining mainstream normative and corporate strategies.