Oogenesis-flight syndrome in crickets: age-dependent egg production, flight performance, and biochemical composition of the flight muscles in adult female Gryllus bimaculatus

Age-dependent changes in flight performance, biochemical composition of flight muscles, and fresh mass of the flight muscles and ovaries were analysed in adult female two-spotted crickets, Gryllus bimaculatus. After the final moult the flight muscle mass increased significantly to a maximum at days 2 and 3. On day 2 the highest flight activity was also observed. Between days 2 and 3 the ovary weight started to rapidly increase due to vitellogenic egg growth, which continued at a high rate until day 10. With the onset of ovarial growth, flight performance decreased and the flight muscles started to histolyse. A high correlation between flight muscle mass and the content of protein, lipid, glycogen, and free carbohydrate in the flight muscle indicated that energy-rich substrates from the degrading flight muscles were used to fuel oogenesis, although flight muscle histolysis can provide only a small fraction of the substrates needed for egg production. In general, there was a clear trade-off between egg production and flight ability. Surprisingly, however, some females possessed well-developed ovaries but displayed no signs of flight muscle histolysis. This observation was corroborated by flight experiments which revealed that, although most flying females had small ovaries, some of them carried an appreciable amount of mature eggs, and thus, somehow managed to evade the oogenesis-flight syndrome.