Annals of Applied Biology ISSN 0003-4746 RESEARCH ARTICLE Effect of temperature on the life history parameters of noctuid lepidopteran stem borers, Busseola fusca and Sesamia calamistis N. Khadioli 1,2 , Z.E.H. Tonnang 1 , G. Ong’amo 1,3 , T. Achia 3,4 , I. Kipchirchir 3 , J. Kroschel 5 & B. Le Ru 6,7 1 ICIPE – African Insect Science for Food and Health, Nairobi, Kenya 2 School of Mathematics, University of Nairobi, Nairobi, Kenya 3 School of Biological Science, University of Nairobi, Nairobi, Kenya 4 School of Public Health, University of the Western Cape, Belville, Republic of South Africa 5 International Potato Center, Lima, Peru 6 Unité de Recherche IRD 072, icipe, African Insect Science for Food and Health, Nairobi, Kenya 7 Université Paris-Sud 11, Orsay, France Keywords Life table parameters; maize stem borer; phenological model. Correspondence B. Le Ru, IRD/ICIPE – African Insect Science for Food and Health, Duduville Campus, Kasarani, P.O. Box 30772–00100, Nairobi, Kenya. Email: bleru@icipe.org Received: 15 November 2013; revised version accepted: 1 May 2014. doi:10.1111/aab.12157 Abstract The influence of temperature on the development, mortality, fecundity and life table parameters of two important noctuid African cereal pests, Busseola fusca and Sesamia calamistis was investigated under laboratory conditions. Experi- ments were carried out with larvae reared on artificial diet under eight con- stant temperatures (12 ∘ C, 15 ∘ C, 18 ∘ C, 20 ∘ C, 25 ∘ C, 28 ∘ C, 30 ∘ C and 35 ∘ C) and a 12L:12D photoperiod. Life table parameters were calculated using Insect Life Cycle Modelling (ILCYM) software. At 12 ∘ C and 35 ∘ C insects failed to develop. Mean development time for both species decreased with increasing tempera- ture for all stages. Between 15 ∘ C and 30 ∘ C, mean larvae development time is divided by four for both species and adult mean longevity is divided by 1.5 and 2.5, for both sexes of S. calamistis and B. fusca, respectively. Fecundity varied according to temperature; the highest was estimated at 22 ∘ C and 24 ∘ C for B. fusca and S. calamistis, respectively. The lower thermal threshold for B. fusca and S. calamistis was, respectively, 6 ∘ C and 9 ∘ C, while the upper thermal threshold was 31 ∘ C and 32 ∘ C, respectively. The highest intrinsic rate of natural increase for B. fusca was obtained at 25 ∘ C while for S. calamistis it was obtained at 28 ∘ C. The highest net reproduction was obtained at 25 ∘ C for both species, but it was higher for S. calamistis than for B. fusca. The shortest population doubling time was observed at 25 ∘ C for B. fusca and at 28 ∘ C for S. calamistis. The optimum temperature range for development of both species was 25–28 ∘ C. The lower lower thermal threshold found for B. fusca than for S. calamistis and the higher upper thermal threshold found for S. calamistis than for B. fusca explain in part the observed distribution of both species in sub-Saharan Africa with S. calamistis occurring in all the agro-ecological zones but being usually more common than B. fusca in savannah lowland and B. fusca reported mainly from mid and high altitude areas. Introduction Lepidopterous stem borers are among the most important insect pests of maize and other gramineous cereal crops in Africa (Kfir et al., 2002). Maize stalk borer, Busseola fusca (Fuller), and the pink stalk borer, Sesamia calamistis Hamp- son, are the two most damaging noctuid species that cause significant maize yield loss in sub-Saharan Africa. These species are indigenous to Africa, and are reported from many countries (Kfir et al., 2002; Chabi-Olaye et al., 2005; Sezonlin et al., 2006). In East and South Africa (Kfir et al., 2002), B. fusca is abundant in the highland areas, how- ever in Central Africa (Cameroon) it has been reported Ann Appl Biol (2014) 1 © 2014 Association of Applied Biologists