Research Article: Predicting the current potential and future world wide distribution of the onion maggot, Delia antiqua using maximum entropy ecological niche modeling

Date Published: February 3, 2017

Publisher: Public Library of Science

Author(s): Shuoying Ning, Jiufeng Wei, Jinian Feng, Hugo Rebelo.


Climate change will markedly impact biology, population ecology, and spatial distribution patterns of insect pests because of the influence of future greenhouse effects on insect development and population dynamics. Onion maggot, Delia antiqua, larvae are subterranean pests with limited mobility, that directly feed on bulbs of Allium sp. and render them completely unmarketable. Modeling the spatial distribution of such a widespread and damaging pest is crucial not only to identify current potentially suitable climactic areas but also to predict where the pest is likely to spread in the future so that appropriate monitoring and management programs can be developed. In this study, Maximum Entropy Niche Modeling was used to estimate the current potential distribution of D. antiqua and to predict the future distribution of this species in 2030, 2050, 2070 and 2080 by using emission scenario (A2) with 7 climate variables. The results of this study show that currently highly suitable habitats for D.antiqua occur throughout most of East Asia, some regions of North America, Western Europe, and Western Asian countries near the Caspian sea and Black Sea. In the future, we predict an even broader distribution of this pest spread more extensively throughout Asia, North America and Europe, particularly in most of European countries, Central regions of United States and much of East Asia. Our present day and future predictions can enhance strategic planning of agricultural organizations by identifying regions that will need to develop Integrated Pest Management programs to manage the onion maggot. The distribution forecasts will also help governments to optimize economic investments in management programs for this pest by identifying regions that are or will become less suitable for current and future infestations.

Partial Text

Climate is one of the principal factors defining the potential range of insects and climate change directly affects the distribution of species [1–2]. Considerable evidence suggests that the average global temperatures will increase by 2–4°C between the present and 2100 under several different greenhouse gas emission scenarios [3–4].Global warming will likely affect almost all aspects of insect life history and population dynamics such as development rate, voltinism, and distribution range [5–8]. Rising temperatures can significantly influence the key physiological characteristics that affect the distribution and seasonal activity of insect pests [9–10] and change the likelihood of severe pest damage by turning climatically unsuitable habitats into suitable ones or vice versa [11–12]. Because of the sensitivity of insects to weather conditions, global climate change will potentially drastically alter pest outbreaks [13–15].

In this study, the MaxEnt model’s current predictions of the most suitable habitats for the development of the onion maggot generally agreed with available host occurrence records. Analyses showed that MaxEnt produced highly accurate predictions of AUC value that was greater than 0.9. Future model predictions from 2030–2080 derived from a IPCC climate change scenario showed that climatic changes would greatly affect the world-wide distribution of this pest, but the specific effects will vary among different locations. In general, the model predicted that there would be an expansion of highly and moderately suitable habitats in most areas in response to global warming, but these more suitable habitats will actually decrease in a few specific locations. Furthermore, the general locations of the most favorable habitats would shift substantially in most countries in response to the predicted climactic changes.