Exposure of insects and host plants to different concentrations of CO2 affects the performance of Mahanarva spectabilis (Hemiptera: Cercopidae) in successive insect generations

Abstract

The performance of three successive generations of Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) fed on four forages exposed to environments with different CO2 concentrations was evaluated. In the first bioassay, we utilized the following scenarios: A) plants and insects were kept at high and constant CO2 (700 ppm) and B) the insects were kept at CO2 700 ppm and fed on plants from the greenhouse (average of 390 ppm). In the second bioassay, we utilized the following scenarios: C) plants and insects were kept in a greenhouse and D) the insects were kept in the greenhouse and fed on plants kept at CO2 700 ppm. The survival and duration of the nymphal and adult stages and the number of eggs/female of M. spectabilis were evaluated. It was only possible to evaluate the cumulative effects of the increase of CO2 on three successive generations of M. spectabilis kept in a greenhouse, due to the reduced survival of the insects in the first generation in the laboratory. A greater direct than indirect effect of the CO2 level on the performance of M. spectabilis was observed. Furthermore, it should be considered that the effect of CO2 elevation on the survival, periods of development, and fecundity, when taken together, can significantly impact the population dynamics of M. spectabilis in future climate scenarios.