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

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.

Exposure of insects and host plants to different concentrations of CO2 affects the performance of Mahanarva spectabilis (Hemiptera: Cercopidae) in successive insect generations / A exposição de insetos e plantas hospedeiras às diferentes concentrações de CO2 afeta o desempenho de Mahanarva spectabilis (Hemiptera: Cercopidae) em sucessivas gerações do inseto

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.

Resumo Avaliou-se o desempenho de três gerações sucessivas de Mahanarva spectabilis (Distant) (Hemiptera: Cercopidae) alimentadas com quatro forrageiras expostas à ambientes com diferentes concentrações de CO2. No primeiro bioensaio, utilizamos os seguintes cenários: A) plantas e insetos foram mantidos em fitotron com CO2 alto e constante (média de 700 ppm) e, B) os insetos foram mantidos em nível de 700 ppm de CO2 e alimentados com plantas advindas da casa de vegetação (média de 390 ppm). No segundo bioensaio, utilizamos os seguintes cenários: C) plantas e insetos foram mantidos em casa de vegetação e, D) os insetos foram mantidos em casa de vegetação e alimentados com plantas mantidas em fitotron. A sobrevivência e duração das fases ninfal e adulta e o número de ovos/fêmea de M. spectabilis foram avaliados. Só foi possível avaliar os efeitos cumulativos do aumento do CO2 em três gerações sucessivas de M. spectabilis mantidas em casa de vegetação, devido à reduzida sobrevivência dos insetos na primeira geração quando mantidos em fitotron. Observou-se maior efeito direto do que indireto do nível de CO2 sobre o desempenho de M. spectabilis. Além disso, deve-se considerar que o efeito da elevação de CO2 sobre a sobrevivência, períodos de desenvolvimento e fecundidade, quando tomados em conjunto, podem impactar significativamente a dinâmica populacional de M. spectabilis em cenários climáticos futuros.