Saturday, September 10, 2016

Invasiveness of spotted wing Drosophila

The polyphagous Asian vinegar fly Drosophila suzukii (spotted wing Drosophila) is a native of Eastern and Southeastern Asia. It emerged as an important invasive insect pest of berries and stone fruits in the Americas and Europe beginning in 2008. Species distribution models are commonly used for analyzing the extant and potential range expansion of invasive species. Previous modeling efforts for D. suzukii include a degree-day model, a MaxEnt ecological niche model, a demographic model incorporating the effects of temperature, and a preliminary mechanistic physiologically-based demographic model (PBDM). In the present analysis, we refine the PBDM for D. suzukii based on biological data reported in the literature. The PBDM is used to assess the effects of temperature and relative humidity from a recently published global climate dataset (AgMERRA) on the prospective geographic distribution and relative abundance of the pest in the USA and Mexico, and in Europe and the Mediterranean Basin. Our focus is on areas of recent invasion and of predicted higher invasiveness in these areas. Although the species is native to Asia and is of putative temperate origins, it has established in subtropical to north temperate zones worldwide where it infests a wide range of wild and domesticated berries and stone fruits. The model captures the observed phenology of D. suzukii at specific locations, as well as the potential geographic distribution and relative favorability across larger regions. The main limiting factor is cold winter temperature in northern areas, though high temperatures and low relative humidity may be limiting in arid areas. The effect of greater cold tolerance in winter morph adults is explored.

Gutierrez A.P., Ponti L., Dalton D.T., 2016. Analysis of the invasiveness of spotted wing Drosophila (Drosophila suzukii) in North America, Europe, and the Mediterranean Basin. Biological Invasions, http://dx.doi.org/10.1007/s10530-016-1255-6 | Full text free to view

Geographic distribution of  Drosophila suzukii in Europe.

Traditional farming and the Mediterranean diet

The Mediterranean diet is described by the UNESCO Cultural Heritage of Humanity website (http://www.unesco.org/culture/ich/en/RL/00884) as encompassing more than just food of the various cultures. These diets are embedded in bio-cultural landscapes that are at risk from global markets, industrial agriculture, invasive species and climate change, and yet little research aimed at conserving this Mediterranean agricultural heritage is being conducted. A focus on preserving traditional Mediterranean agricultural systems provides unique opportunities to link UNESCO-SCBD’s Joint Programme on Biological and Cultural Diversity (http://www.cbd.int/lbcd/​) and FAO’s Globally Important Agricultural Heritage Systems initiative (GIAHS, http://www.fao.org/giahs/) with the goal of developing strategies and policy to preserve this heritage and the food production systems that are its basis for future generations. An important step in this direction is the development of holistic ecosystem-level assessments of the stability and resilience of traditional Mediterranean farming systems to evolving global change including climate change and shifting economic patterns and associated landscape transformations. A holistic approach is an important step to ensure ecologically sustainable development, conserve cultural identities, improve farming community livelihood, preserve agro-biodiversity and ensure the continued provision of vital ecosystem services for humanity.

Ponti L., Gutierrez A.P., Altieri M.A., 2016. Preserving the Mediterranean diet through holistic strategies for the conservation of traditional farming systems. In: Agnoletti M., Emanueli F. (eds.), Biocultural Diversity in Europe, Springer International Publishing, Switzerland: 453-469. http://dx.doi.org/10.1007/978-3-319-26315-1_24

Linking UNESCO-SCBD’s Joint Programme on Biological and Cultural Diversity and FAO’s GIAHS initiative may help preserve the traditional Mediterranean agricultural heritage.

Thursday, May 12, 2016

Invasion biology of Drosophila suzukii

The Asian vinegar fly Drosophila suzukii [spotted wing Drosophila (SWD)] has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, common themes in the invasion biology of SWD are explored by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. The review concludes that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions.

Asplen M.K., Anfora G., Biondi A., Choi D-S., Chu D., Daane K.M., Gibert P., Gutierrez A.P., Hoelmer K.A., Hutchison W.D., Isaacs R., Jiang Z-L., Kárpáti Z., Kimura M.T., Pascual M., Philips C.R., Plantamp C., Ponti L., Vétek G., Vogt H., Walton V.M., Yu Y., Zappalà L., Desneux N., 2015. Invasion biology of spotted wing drosophila (Drosophila suzukii): a global perspective and future priorities. Journal of Pest Science, 88: 469-494. http://dx.doi.org/10.1007/s10340-015-0681-z

Drosophila suzukii (http://www.terraevita.it/drosophila-suzukii-danni-e-contromisure/).

Thursday, November 26, 2015

PBDMs for evidence-based pest risk assessment

The distribution and abundance of species that cause economic loss (i.e., pests) in crops, forests or livestock depends on many biotic and abiotic factors that are thought difficult to separate and quantify on geographical and temporal scales. However, the weather-driven biology and dynamics of such species and of relevant interacting species in their food chain or web can be captured via mechanistic physiologically based demographic models (PBDMs) that can be implemented in the context of a geographic information system (GIS) to project their potential geographic distribution and relative abundance given observed or climate change scenarios of weather. PBDMs may include bottom-up effects of the host on pest dynamics and, if appropriate, the top-down action of natural enemies. When driven by weather, PBDMs predict the phenology, age structure and abundance dynamics at one or many locations enabling projecting the distribution of the interacting species across wide geographic areas. PBDMs are able to capture relevant ecosystem complexity within a modest number of measurable parameters because they use the same ecological models of analogous resource acquisition and allocation processes across all trophic levels. The use of these analogies makes parameter estimation easier as the underlying functions are known. This is a significant advantage in cases where the available biological data is sparse.

Ponti L., Gilioli G., Biondi A., Desneux N., Gutierrez A.P., 2015. Physiologically based demographic models streamline identification and collection of data in evidence-based pest risk assessment. EPPO Bulletin, 45: 317-322. http://dx.doi.org/10.1111/epp.12224

PBDM sub-models used for all species.