Effects of post-eclosion light-dark regimes on mating performance of mass-reared tephritid fly Anastrepha ludens

Many insect species show daily rhythms in their reproductive behaviour, with male and female cycles often being synchronized by photoperiod. In mass-rearing facilities, many environmental factors, including photoperiod, are standardized to favour insect production. However, these standardizations could affect sexual performance. Herein we studied, under semi-natural conditions, the effect of different photoperiods on the copulation behaviour of mass-reared Anastrepha ludens Loew (Diptera: Tephritidae) flies. Adult flies were exposed to six combinations of light conditions during the first 12 days after eclosion: (1) 12 days under a L12:D12 h regime (12-LD), (2) 8 days under L12: D12 followed by 4 days in complete darkness (8-L:4-D), (3) 4 days under L12: D12, then 8 days in darkness (4-L:8-D), (4) 12 days in darkness (12-D), (5) 8 days in darkness, then 4 days under L12: D12 (8-D: 4-L), and (6) 4 days in darkness followed by 8 days under L12: D12 (4-D: 8-L). On day 13, field-cage tests were carried out to determine fly mating performance. There was a sex-specific effect of light regime on fly copulation behaviour. Females exposed to absolute darkness during periods longer than 4 days had fewer copulations compared with females subjected to other light regimes. In contrast, periods of darkness of 8 or 12 days immediately before the field test affected male mating performance. There was no significant difference in the latency to copulation or in copula duration among males or females of the six treatments. We conclude that a period of 4 days under dark conditions does not affect male mating performance. We discuss our results in terms of the light conditions encountered by mass-reared tephritids when emerging in packing devices, which may negatively affect their sexual performance once released in the field.