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Ophraella communaLeSage is native to North America and a biological control agent of the invasive weedAmbrosia artemisiifoliaL. SinceA. artemisiifoliaplants grow old and die after September annually,O. communasuffers from food shortage. To understand the effect of food shortage or deprivation on population fitness ofO. communa, the development and fecundity and hatchability of its progeny eggs were observed when larvae were offeredA. artemisiifoliaplants for either 3, 6, 12 or 24 hours daily. The results showed that larval food deprivation significantly influenced survival and developmental durations of larvae and pupae. Survival rates and developmental durations of larvae and pupae decreased and were prolonged significantly with decreasing time of larval daily food intake. Longevity and fecundity of adults shortened and decreased significantly with decreasing time of larval daily food intake. In addition, the hatch rates of progeny eggs decreased significantly with decreasing time of larval daily food intake. The present study suggests that food shortage is one of the most critical factors that suppressesO. communapopulations. This can explain why field populations of the beetle decrease significantly with ageing and death ofA. artemisiifoliaplants after late September. [ABSTRACT FROM AUTHOR]

Life-history strategies of animals are governed by fitness-related trait trade-offs. In particular, the age at which either one of the two sexes copulate has been shown to affect insect reproductive output and longevity. This suggests that trade-offs between longevity and reproduction might drive the choice of a mating partner based on their age and ultimately such choices might select for different life-histories. Although several studies indicate that female age at mating dictates subsequent insect longevity, fecundity, and egg hatch rate, it is unclear how male age at copulation affects these life-history traits. In this study, we simultaneously investigated the effects of female and male age on female fecundity, eggs hatch rate, and adult longevity inOphraella communaLeSage (Coleoptera: Chrysomellidae), the primary biological control agent of the invasive common ragweed,Ambrosia artemisiifoliaL. We found that young mature females lived significantly longer when they were mated with older males. Maximum female fecundity and subsequent egg hatch rate occurred when young females mated with 3-day-old males. On the other hand, females lived longer when mating with an older male. These findings are in accordance with the cost-of-reproduction concept. [ABSTRACT FROM PUBLISHER]