Differences in mate acceptance and host plant recognition between wild and laboratory-reared Busseola fusca (Fuller) P.-A. Calatayud 1 , G. Juma 1 , P. G. N. Njagi 2 , N. Faure 3 , S. Calatayud 1 , S. Dupas 3 , B. Le Ru ¨ 1 , G. Magoma 4 , J.-F. Silvain 3 & B. Fre ´ rot 5 1 IRD, UR 072, c/o ICIPE, Nairobi, Kenya 2 ICIPE, Behavioural and Chemical Ecology Department, Nairobi, Kenya and Universite ´ Paris-Sudii, Orsay, France 3 IRD, UR 072, c/o CNRS, Laboratoire Evolution, Ge ´ nomes et Spe ´ ciation, Gif-sur-Yvette, France and Universite ´ Paris-Sudii, Orsay, France 4 Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya 5 INRA UMR 1272, PISC, Versailles, France Introduction Regular availability and adequate numbers of insects for experimental purposes can be easily obtained by mass rearing in the laboratory. However, rearing of insects under laboratory or artificial conditions for several generations can cause drastic changes both phenotypically and genotypically. Phenotypic changes generally occur in host plant acceptability/ recognition, pheromonal responses and in reproduc- tive parameters respectively (Tingey 1986; Masson et al. 1987). In addition, some insect species may lose their ability to successfully develop on their ori- ginal host (Guthrie and Carter 1972). In other cases, they develop a tendency to accept plants outside their known natural host range (Schoonhoven 1967). Genetic alterations can include loss of genes, decreases in heterozygosity, and shifts in allele fre- quencies (Masson et al. 1987; Norris et al. 2001). The latter may be caused by random genetic drift, founder effects, and non-random mating and mate selection. The stemborer, Busseola fusca (Fuller) (Lep.: Noc- tuidae), is an important pest of maize and sorghum in sub-Saharan Africa (Kfir et al. 2002). At the Inter- national Centre of Insect Physiology and Ecology (ICIPE, Nairobi, Kenya), B. fusca has been success- fully reared under laboratory conditions for several generations on a meridic diet developed by Onyango and Ochieng’-Odero (1994). Wax papers rolled helic- oidally to form cylindrical artificial stems were used as oviposition supports for the female moths. Keywords Africa, female calling, maize, male attraction, stem borer, surrogate stem Correspondence P.-A. Calatayud (corresponding author), IRD, UR 072, c/o ICIPE, PO Box 30772-00100, Nairobi, Kenya. E-mail:pcalatayud@icipe.org Received: June 28, 2007; accepted: November 14, 2007. doi: 10.1111/j.1439-0418.2007.01261.x Abstract The present study was aimed at characterizing differences in mate accep- tance and host plant recognition between Busseola fusca (Lep.: Noctui- dae) reared for several generations under laboratory conditions and wild conspecifics, directly collected from maize stems in the field. The mating success was significantly higher in laboratory reared when compared with the wild B. fusca population. Oviposition on artificial stems was sig- nificantly higher for laboratory-reared insects than for the wild ones. Moreover, unlike adults of the wild strain, laboratory-reared B. fusca showed no preference to oviposit on surrogate stems impregnated with maize extracts. Long-range attraction to the host plant was significantly lower for laboratory-reared insects. Furthermore, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of mitochondrial DNA showed that the wild type and laboratory popula- tions belonged to the same genetic strain, indicating that these differ- ences between the populations were mainly phenotypic. J. Appl. Entomol. J. Appl. Entomol. 132 (2008) 255–264 ª 2008 The Authors Journal compilation ª 2008 Blackwell Verlag, Berlin 255