Abstract:

In order to clarify the influence of different temperatures on the spawning mechanism of M. dilatata, and lay a theoretical foundation for the large-scale breeding and application of M. dilatata, three temperature treatments were set, including constant temperature at 25℃, variable temperature at 25/30℃ and constant temperature at 30℃. The pre-spawning period, egg production amount, hatchability rate and adult weight of M. dilatata in each treatment were recorded during the experimental process. The results showed that there was no significant difference in egg production between 25℃ constant temperature, 25/30℃ variable temperature, and 30℃ constant temperature, and there was no significant difference in pre-spawning and male and female body weight. On days 10th and 25th after the start of spawning, the hatchability of 25℃ constant temperature was significantly higher than that of 30℃ constant temperature and 25/30℃ variable temperature (P<0.05), and there was no significant difference in the hatchability of the eggs during the 30-day observation cycle, there was no significant difference in hatchability of the next generation eggs between treatment groups. This study showed that 25/30℃ variable temperature and 30℃ constant temperature reduced the hatchability of eggs of M. dilatata to some extent and had no effect on pre-spawning, egg production and adult weight. This study could provide the data basis for the spawning mechanism and application of M. dilatata.

Key words: Aphis craccivora Koch, Megalocaria dilatata, temperature, biological control