IntroductionBostrichids are generally wood and twig borers, but species in three genera, Prostephanus truncatus (Horn), Dinoderus bifoveolatus (Wollaston) and Rhyzopertha dominica (F.), became facultatively associated with stored cereals. , dried starchy tubers and ground products. In West Africa, Dinoderus bifoveolatus can be found infesting dried cassava chips (Borgemeister et al, 2000). P. truncatus is widely distributed in Mexico and Central America, while Rhyzopertha dominica is a pest of stored wheat and other small grains worldwide (reviewed in Edde and Phillips, 2006). Large aggregations of both sexes can form in the stored products of bostricid pests in response to pheromones released by signaling individuals, usually males (Borgemeister et al, 2000, Hodges 2002, Khorramshahi and Burkholder, 1981).R. Dominica's aggregation pheromones have been identified as (S)-(+)-1-methylbutyl (E)-2-methyl-2-pentenoate and (S)-(+)-1-methylbutyl ( E)-2,4-dimethyl-2-pentenoate, commonly known as Dominicalure-1 (DL-1) and Dominicalure-2 (DL-2), respectively (Williams et al., 1981; Khorramshahi and Burkholder, 1981). These pheromones produced by males are only released during feeding and the volatile emissions of other insect or plant species do not contain DL-1 or DL-2. Field tests with synthetic dominicalure conducted in or near grain warehouses (Cogburn et. al. 1984, Leo-Martinez et al 1987) and in experiments with olfactometers (Khorramshahi and Burkholder, 1981, Dowdy 1993) showed that there was no difference in the responses of individuals. beetles to both compounds, individually and in combination. Captured R. dominica were biased towards females in olfactometric studies or in aerial traps baited with mixtures of the two compounds (e.g. Bashir et al 2001, Edde et...... middle of article.. .... similar behavioral responses on both sexes of the beetle, but attraction increases with dosage (ref), indicating that these pheromones are behaviorally redundant, i.e. each functions as an assurance of safety for each other. Therefore, males of this species produce two aggregation pheromones with the assumption of a single, multicomponent pheromone, and thus referring to each distinct chemical as a "component." of pheromone", as entomologists believed, there are several examples in which a volatile host plant is a synergist with pheromones produced by insects. Compounds produced by insects, pheromones, are only active against members of the insect. he insect species, but the required plant volatile cannot be called a pheromone since it is an interspecific semiochemical, and therefore a kairomone. These definitions were discussed by Nordlund and Lewis. (1981).