Artificial Light at Night Does Not Elicit Transgenerational Effects in the Pacific Field Cricket, Teleogryllus oceanicus

ABSTRACT

Artificial light at night (ALAN) is a pervasive anthropogenetic pollutant and a powerful chronodisruptor, as it can mask environmental light cues and negatively influence circadian and seasonal biological processes. Within‐generation negative effects of ALAN have been recorded across a broad range of species. However, few studies have explored the transgenerational impacts of ALAN exposure, and thus, the effect of parental exposure on offspring fitness is poorly understood. Here, we investigated the effect of within‐generation and transgenerational ALAN exposure on key life history traits in the Pacific field cricket, Teleogryllus oceanicus . We exposed parental crickets to either ALAN (10 lx) or dark‐at‐night (0 lx) conditions and then mated them to a partner previously exposed to either the same or opposite lighting treatment, resulting in four parental treatments. Offspring were then reared under either ALAN or dark‐at‐night conditions. We found no evidence of ALAN‐related transgenerational fitness effects in the offspring: Body weight, reproductive effort and immune function were comparable regardless of parental treatment. However, consistent with previous work, we found within‐generation effects of ALAN exposure: ALAN‐exposed male and female offspring had lower body mass compared with those reared in darkness. Why ALAN failed to elicit a transgenerational effect is unclear but may reflect the mechanistic basis of ALAN as a chronodisruptor that does not induce heritable changes, the moderate oxidative stress it induces, the limited duration of parental exposure we applied, or the benign rearing conditions under which offspring faced no physiological constraints. Future research into these areas is critical, as ALAN continues to increase globally.