Thermal Stress as a Critical Factor in the Viability and Duration of Spittlebug Eggs

The spittlebug Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) is an important pest that causes significant losses in the production of forage crops for cattle feed. Information on the thermal requirements of this insect during the egg stage is crucial in assessing the interaction between insects and forage. The aim of this research was to evaluate the effects of constant and oscillating (diurnal/nocturnal) temperatures on the viability of M. spectabilis eggs and the duration of the egg stage. Temperatures of 20 °C to 30 °C were ideal for the development of this insect pest, resulting in greater viability and faster development of the embryos. In addition, it should be noted that a variation of up to 8 days is feasible for synchronizing the phenological stages of the forage plants and the eggs to be laid on these plants when subjected to 30 °C (16.6 days) or 20 °C (25.7 days) without significantly altering the viability of the eggs. Notably, a temperature oscillation of 25 °C during the day and 15 °C at night increased the viability of the eggs after exiting diapause. These results are essential for the rearing of M. spectabilis in the laboratory, allowing for the supply of eggs for experiments and contributing to advances in studies aimed at developing effective integrated management strategies for this pest.