Diurnal temperature amplitude affects diamondback moth adult and next‐generation traits

Temperature fluctuation is one of the most important factors in climate change, and research into its effects on organisms is increasing. Nonetheless, few studies have addressed its effects on insects and particularly on the parental generation. We therefore simulated temperature amplitudes (+/- 0, 4, 6, 8, 10 degrees C) for a mean environmental temperature of 25 degrees C and studied their immediate and maternal effects on a global pest, the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae), focusing on adult longevity and fecundity and egg development and survivorship in the next generation. Relative to constant temperature, moderate amplitudes (4 and 6 degrees C) did not affect the adults, whereas 8 and 10 degrees C amplitudes hindered adult longevity and fecundity, but significantly increased the proportional of early fecundity after each treatment. Temperature amplitude 10 degrees C inhibited development of Day 2 and Day 3 laid eggs. These findings show that temperature amplitude affects both the maternal and offspring phenotype and indicate that the influence of temperature amplitude on diamondback moth population models requires further research.