Multiparasitism of Piezodorus guildinii eggs by Telenomus podisi and Trissolcus urichi

Multiparasitism involves competition between larvae inside the host. Telenomus podisi (Ashmead) and Trissolcus urichi (Crawford) (Hymenoptera: Platygastridae) are solitary egg parasitoids of Piezodorus guildinii Westwood (Hemiptera: Pentatomidae), an important soybean pest. Egg masses partially parasitized by one species were offered to females of the other species. Both species attacked randomly unparasitized and parasitized hosts. Emergence from multiparasitized eggs was greater for T. urichi than for T. podisi, although it was lower than emergence from eggs parasitized by T. urichi alone. Emergence of each species was independent of the order in which they parasitized and of time elapsed between ovipositions. Progeny sex ratio obtained from multiparasitized and from parasitized eggs were similar for both parasitoids. Our results suggest that T. urichi is a better intrinsic competitor than T. podisi for P. guildinii eggs. In the field, however, T. podisi was the dominant species, and T. urichi could be using other pentatomid eggs as resource.Fil: Cingolani, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Greco, Nancy Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Liljesthrom, Gerardo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; Argentin

Optimal allocations of agricultural intensity reveal win-no loss solutions for food production and biodiversity

publication en ligne 23 avril 2016Reconciling biodiversity conservation and food production may require the fine-tuning of both agricultural intensity and its spatial allocation. Here, we explored whether the optimization of allocation of intensity could improve food production and biodiversity outcomes. We developed a spatially explicit, multi-criteria optimization model for agricultural intensity allocation at the scale of France and at the resolution of small agricultural regions (SARs) with a mean area of 669.6 km2. Three thousand allocations were randomly simulated and then optimized under three scenarios: intensification, extensification, and reallocation. Optimization was based on food production and biodiversity outcomes using several metrics, such as habitat specialization and trophic level, that reflect the composition of farmland bird communities. The optimization was based on derived statistical relationships between intensity and the production and biodiversity metrics at the SAR scale using national agricultural statistics and bird census data. Simulations showed that optimal allocations modulated the trade-off among criteria and led to increased efficiency, with optimal extensification increasing biodiversity and minimizing production losses. Furthermore, we revealed “win-no loss” solutions. For example, optimal intensification increased production with almost no biodiversity loss and optimal reallocation benefited biodiversity with almost no cost to production. A variety of agricultural intensity levels were necessary to maintain a diversity of farmland bird communities at the national scale. Although we demonstrate that optimal allocation of intensity can be a powerful means of reconciling diverse criteria at the national scale, its implementation will require new mechanisms for spatially targeted and coordinated policies

The Lorax complex: deep ecology, ecocentrism and exclusion

Biodiversity preservation is often viewed in utilitarian terms that render non-human species as ecosystem services or natural resources. The economic capture approach may be inadequate in addressing biodiversity loss because extinction of some species could conceivably come to pass without jeopardizing the survival of the humans. People might be materially sustained by a technological biora made to yield services and products required for human life. The failure to address biodiversity loss calls for an exploration of alternative paradigms. It is proposed that the failure to address biodiversity loss stems from the fact that ecocentric value holders are politically marginalized and underrepresented in the most powerful strata of society. While anthropocentric concerns with environment and private expressions of biophilia are acceptable in the wider society, the more pronounced publicly expressed deep ecology position is discouraged. “Radical environmentalists” are among the least understood of all contemporary opposition movements, not only in tactical terms, but also ethically. The article argues in favor of the inclusion of deep ecology perspective as an alternative to the current anthropocentric paradigm. https://doi.org/10.1080/1943815X.2012.742914 https://www.linkedin.com/in/helenkopnina