Asymmetric oviposition behaviour between Drosophila suzukii and D. subpulchrella suggests competition for the shared niche in their native range

Release from competitors is one of the mechanisms ascribed to the ecological success of invasive species outside their native range (competitive release hypothesis). However, studies describing the natural competitors of invasive species in their homeland are limited.
Drosophila suzukii, the spotted-wing drosophila, is an invasive pest of small fruits expanding its range worldwide, whereas D. subpulchrella, the most closely related species to D. suzukii, remains endemic to the native range of D. suzukii. D. subpulchrella is inferior to D. suzukii in terms of the host usage capability, and it has not been considered as a major competitor of D. suzukii.
This study examined the interaction between the two species in egg-laying behaviour. A field survey revealed that 11% of wild berries were co-infected by both species. In the laboratory experiments, D. suzukii avoided oviposition substrates that had already been oviposited by either conspecific or D. subpulchrella females, whereas D. subpu..., , , # Asymmetric oviposition behaviour between *Drosophila suzukii* and *D. subpulchrella* suggests competition for the shared niche in their native range

[https://doi.org/10.5061/dryad.1ns1rn946](https://doi.org/10.5061/dryad.1ns1rn946)

## Description of the data and file structure

Field survey

Wild berries (*Rubus hirsutus, R. palmatus, R. crataegifolius, R. microphyllus, Cerasus jamasakura, Morus australis*) were collected in a mountainous area (450 ~ 650 m of elevation) in Hachioji, Tokyo once in a week from May to June in 2023. The field consists of two sites, separated from each other by 600 m in the horizontal distance and 200 m in the altitude. At each site, berries were collected from several patches, each selected to be at least 20 m distant from the other patches. At each patch, 10 fruits were collected. The fruits were individually transferred into glass vials within the day and maintained at 20°C until adults emerged. The species and sex of the emerged Drosophila flies were...