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Effect of temperature on the phenology of Chilo partellus (Swinhoe) (Lepidoptera, Crambidae); simulation and visualization of the potential future distribution of C. partellus in Africa under warmer temperatures through the development of life-table parameters

Published online by Cambridge University Press:  17 September 2014

N. Khadioli
Affiliation:
Icipe – African Insect Science for Food and Health, P.O. Box 30772-00100, Nairobi, Kenya
Z.E.H. Tonnang
Affiliation:
Icipe – African Insect Science for Food and Health, P.O. Box 30772-00100, Nairobi, Kenya
E. Muchugu
Affiliation:
Icipe – African Insect Science for Food and Health, P.O. Box 30772-00100, Nairobi, Kenya
G. Ong'amo
Affiliation:
Icipe – African Insect Science for Food and Health, P.O. Box 30772-00100, Nairobi, Kenya
T. Achia
Affiliation:
School of Mathematics, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya School of Public Health, University of the Western Cape, Bellville, Cape Town 7535, South Africa
I. Kipchirchir
Affiliation:
School of Mathematics, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
J. Kroschel
Affiliation:
International Potato Center, Apartado 1558, Lima 12, Peru
B. Le Ru*
Affiliation:
Unité de Recherche IRD 072, Icipe – African Insect Science for Food and Health, P.O. Box 30772, Nairobi, Kenya or Université Paris-Sud 11, 91405 Orsay cedex, France
*
*Author for correspondence Phone: 254 (0) 20 8632055: Fax: 254 (0) 20 8632001 or 8632002 E-mail: bleru@icipe.org

Abstract

Maize (Zea mays) is a major staple food in Africa. However, maize production is severely reduced by damage caused by feeding lepidopteran pests. In East and Southern Africa, Chilo partellus is one of the most damaging cereal stem borers mainly found in the warmer lowland areas. In this study, it was hypothesized that the future distribution and abundance of C. partellus may be affected greatly by the current global warming. The temperature-dependent population growth potential of C. partellus was studied on artificial diet under laboratory conditions at six constant temperatures (15, 18, 20, 25, 28, 30, 32 and 35 °C), relative humidity of 75±5% and a photoperiod of L12:L12 h. Several non-linear models were fitted to the data to model development time, mortality and reproduction of the insect species. Cohort updating algorithm and rate summation approach were stochastically used for simulating age and stage structure populations and generate life-table parameters. For spatial analysis of the pest risk, three generic risk indices (index of establishment, generation number and activity index) were visualized in the geographical information system component of the advanced Insect Life Cycle modeling (ILCYM) software. To predict the future distribution of C. partellus we used the climate change scenario A1B obtained from WorldClim and CCAFS databases. The maps were compared with available data on the current distribution of C. partellus in Kenya. The results show that the development times of the different stages decreased with increasing temperatures ranging from 18 to 35 °C; at the extreme temperatures, 15 and 38 °C, no egg could hatch and no larvae completed development. The study concludes that C. partellus may potentially expands its range into higher altitude areas, highland tropics and moist transitional regions, with the highest maize potential where the species has not been recorded yet. This has serious implication in terms of food security since these areas produce approximately 80% of the total maize in East Africa.

Type
Research Papers
Copyright
Copyright © Cambridge University Press 2014 

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