Populations’ growth of cigarette beetle, Lasioderma serricorne, on stored tobacco under temperate and tropical conditions

Abstract: The cigarette beetle, Lasioderma serricorne (F.) (Coleoptera: Anobiidae), is a well-known insect that infests a wide range of foodstuffs and it is the most serious pest of stored tobacco and cocoa. Cigarette beetle (CB) is a well adapted species in tropical and temperate environmental conditions, although the variability of temperature is a very important ecological factor, which insects can answer in a differently way under the presence/absence of temperature fluctuation. The rhythms of temperature, together with light, moisture and food, control the seasonal and daily insects’ activity. Experiments were carried out to study the activity of adults under temperate and tropical conditions, in tobacco and cigarette factories and warehouses in Portugal and in a cigarette factory and warehouses in Cape Verde. The records of adults’ activity were obtained monthly using traps with sex pheromone and the environmental conditions of temperature and relative humidity were achieved from thermohygrographs and data loggers. The population growth was calculated based on index of “relative” growth = ΔΝ/Δt (“relative” because was supported on records obtained from trap catches) where ΔΝ is the variation of the adults caught in a given period (month) of time and Δt is the period of time (month). From the results, larvae hibernation was not observed in Cape Verde and the adults remain active all over the year while in the premises in Portugal there was a period where their activity was lower or absente. The index of relative growth of the CB populations in Portugal was greater when compared with populations in Cape Verde. This different behavior indicated that temperature fluctuations may have a stimulant effect on the population growth.