Early or late: Associations between adult emergence timing and fitness‐related traits in the grapevine moth <i>Lobesia botrana</i>

Abstract The timing of adult emergence is often closely associated with individual condition and reproductive success across a wide range of taxa. In insects, emergence timing can reflect both intrinsic developmental differences and environmental conditions experienced during earlier life stages and is often correlated with key fitness traits. Individuals also have to synchronise their emergence with fluctuating resource availability, and the population benefits when individuals emerge at different times, by reducing the chance that a single adverse event will affect all offspring in one season. This balance is particularly evident in insects, where synchronising life stages with optimal environmental conditions, such as the phenological stages of host plants, is essential. In this study, we described associations between adult emergence timing and multiple components of individual quality in a wild population of the grapevine moth Lobesia botrana (a major pest of grapevines) according to their host plant. Our findings revealed a reduction in pupal mass and adult longevity with later emergence. Later emergence also impacted mating (decreased mating success, increased mating latency and mating duration) and reproductive‐related traits (reduction in spermatophore volume, fecundity and fertility). Additionally, the impact of emergence timing is more pronounced in individuals originating from Mourvedre compared to Syrah, two distinct grape varieties. This suggested that the quality of larval host is closely tied to the timing of emergence, indicating a complex interplay between emergence timing and host plant quality.