Archive for the ‘Medfly’ Category

Analysis of invasive insects: links to climate change

September 12, 2014 Leave a comment

Climate change is expected to alter the geographic distribution and abundance of many species, to increase the invasion of new areas by exotic species and, in some cases, to lead to extinction of species. This chapter reviews some of the links between invasive insects and climate change. The effects of climate change on insect pest populations can be direct, through impacts on their physiology and behaviour, or indirect, through biotic interactions (i.e. bottom-up and top-down eff ects). Anthropogenic climate and global change is expected to be a major driver in the introduction, establishment, distribution, impact and changes in the efficacy of mitigation strategies for invasive species. To address these problems, we must be able to predict climate change impacts on species distribution and abundance. Commonly used ecological niche modelling approaches have implicit assumptions about the biology of the target species and attempt to characterize the ecological niche using aggregate weather and other factors in the area of recorded distribution. More holistic physiologically based demographic modelling approaches explicitly describe the biological and physiological responses of species to weather and the species they interact with on fine temporal and spatial scales. The geographic distribution and relative abundance of four invasive insect pests are reviewed under observed and +2°C weather scenarios across the USA and Mexico: the tropical New World screwworm, the pink bollworm, the Mediterranean fruit fly (i.e. medfly) and the olive fly. The distribution of the olive fly is examined across the Mediterranean basin to illustrate the transferability of the model to analyses of new regions and climate change scenarios.

Gutierrez A.P., Ponti L., 2014. Analysis of invasive insects: links to climate change. In: Ziska L.H., Dukes J.S., (eds.), Invasive Species and Global Climate Change. CABI Publishing, Wallingford, UK. ISBN: 978-1780641645.

Dry matter partitioning in a ladybeetle PBDM.

Ultra-low, cryptic tropical fruit fly populations

March 12, 2014 Leave a comment

A comment appeared in Proceedings B reviews a study by Papadopoulos, Plant, and Carey (2013; “From trickle to flood: the large-scale, cryptic invasion of California by tropical fruit flies.” Proc. R. Soc. B: Biol. Sci. 280: and suggests an alternative approach that addresses the biology of invasive species. In summary, inference of establishment of fruit flies based on recurrence data as performed by Papadopoulos et al. (2013) is neither explanatory nor provides confirmation of establishment in California. By contrast, physiologically based demographic models for medfly and olive fly accurately predict the potential distribution of the two fruit flies in California and elsewhere, and provide explanation for species phenology and dynamics that is critical for risk assessment and policy development for these and other invasive species under current climate and climate change scenarios.

Gutierrez A.P., Ponti L., Gilioli G., 2014. Comments on the concept of ultra-low, cryptic tropical fruit fly populations. Proceedings of the Royal Society B: Biological Sciences, 281,

Invasive potential of medfly in California and Italy

February 25, 2011 Leave a comment

Since being detected in California in 1975, the polyphagous tropical Mediterranean fruit fly (Ceratitis capitata Weid. (medfly)) has been the subject of a large-scale eradication campaign in the absence of sound knowledge of its invasive potential. We use a weather-driven physiologically-based demographic system model (CASAS) embedded in a GIS based on GRASS to examine medfly’s potential distribution across Arizona-California (AZ-CA), and Italy where its establishment is documented. AZ is unfavorable for medfly because of high summer temperatures, while much of CA, including many frost-free areas, is too cold during winter. Only the south near coastal region of CA is predicted to be potentially favorable for medfly, but in the absence of consistent measurable populations, we cannot say if medfly is established there. Medfly has been established in Italy for decades, and our model predicts a wide distribution in the southern and western regions of the country.

Gutierrez A.P., Ponti L., 2011. Assessing the invasive potential of the Mediterranean fruit fly in California and Italy. Biological Invasions, DOI 10.1007/s10530-011-9937-6.