DOI: 10.3897/bull.insectology.158738

Authors: Wioleta Koźbiał, Elżbieta Wójcik-Gront, Mariusz Lewandowski

Abstract: The spotted wing drosophila (Drosophila suzukii) is an invasive pest causing significant damage to soft fruit crops in Europe. Native parasitoids may contribute to its biological control, yet information on their distribution and seasonal activity in Central Europe remains limited. This study aimed to investigate the species composition and seasonal dynamics of Drosophila parasitoids in agricultural and adjacent semi-natural habitats in Poland. Fieldwork was conducted during the early, middle, and late vegetation seasons in 2021–2022 using self-constructed traps baited with Drosophila melanogaster and D. hydei as hosts. Parasitoids emerging from collected traps were identified and quantified. Three hymenopteran parasitoid species were recorded: the larval parasitoid Asobara tabida and the pupal parasitoids Trichopria drosophilae and Pachycrepoideus vindemmiae. P. vindemmiae was the most abundant species, particularly in mid-season and in semi-natural areas. T. drosophilae dominated in the early season, while A. tabida was consistently less numerous. The overall parasitoid abundance was significantly higher in semi-natural habitats compared to agricultural sites. The structure of parasitoid assemblages changed with the season, with the highest species evenness in early and mid-season samples. These results highlight the influence of habitat type and seasonality on parasitoid occurrence and suggest that certain native species, especially P. vindemmiae and T. drosophilae, could contribute to the conservation biological control of D. suzukii. Promoting semi-natural refuges may enhance the presence and persistence of beneficial parasitoids in agricultural landscapes.

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DOI: 10.3897/bull.insectology.164055

Authors: Reinhard Lakes-Harlan, Marie-Sa Do, Joscha A. Alt

Abstract: Here we introduce a mobile trackball system for measuring phonotactic behaviour of insects in the field. The trackball system allows generating quantitative behavioural data in the field. Experiments for determination of the phonotactic threshold of two insect species of a parasitoid-host system proofed the utility and usability of this method. The threshold of the parasitoid fly Emblemasoma auditrix (Shewell, 1976) in response to the calling song of the host cicada Okanagana rimosa (Say, 1830) could be confirmed with 61 dB SPL. The behavioural threshold of female cicadas O. rimosa could be determined for the first time to 62 dB SPL. Thus, the mobile system allowed testing of the cicada in the field, which was not possible in laboratory environment. Generally, it was possible to test animals that exhibit certain behaviours only outdoors and to test intact animals and to release them immediately after completion of the experiment. With this method, it will also be possible to test animals under real environmental conditions, for example, in respect to noise.

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DOI: 10.3897/bull.insectology.154143

Authors: Csaba Nagy, Emre Şen, Balázs Kiss

Abstract: Our study reports the first occurrence of Zaprionus indianus Gupta, 1970 (Diptera: Drosophilidae) in Hungary, representing the northernmost European record of this thermophilic species. Specimens were captured in October 2023 during a large-scale Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) monitoring program conducted in sweet cherry orchards in north-central Hungary. A total of five individuals (one female and four males) were caught at two different orchards 1 km apart, using modified pan and bottle traps baited with apple cider vinegar-based lures. No specimens were detected in the previous year (2022) or the following year (2024), which may indicate a transient population, though further monitoring would be required to confirm the lack of establishment. Although the overwintering of the species appears unlikely in Hungary, climate change may facilitate its future range expansion. Our findings highlight the importance of continuous monitoring of invasive drosophilids in Central Europe for better understanding their establishment potential and agricultural risks.

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DOI: 10.3897/bull.insectology.152894

Authors: Mehran Rezaei, Mohammad Mehrabadi, Ali Asghar Talebi, Maryam Atapour

Abstract: To better understand the biology of Compsilura concinnata (Meigen) as a potential biological control agent, it is necessary to determine suitability for potential hosts. In this study, laboratory tests were performed to investigate the acceptance and suitability of two key insect pests, e.g. Pieris rapae (L.) and Spodoptera litura (Fabricius) as host species for C. concinnata. In the first experiment, no significant difference was found for larval and pupal development duration, male and female puparium weight, female longevity period, sex ratio, adult yield, and fecundity of C. concinnata between P. rapae and S. litura. However, the parasitism rate and the host larval mortality were significantly higher for S. litura (58.37% and 65.82%, respectively) than for P. rapae (54.21% and 62.26%, respectively), but the values were very close between the two pests. In the second experiment, it was found that the ability of the parasitoid to locate between the hosts was insignificant. Nevertheless, the mean time to deposit two C. concinnata larvae was significantly longer for S. litura than P. rapae (third experiment). Overall, this finding indicates that C. concinnata could effectively contribute to lowering the population size of P. rapae and S. litura. Further studies must be done to apply C. concinnata successfully against these two host species in field and semi-field conditions.

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