Impact of freezing on the emergence of Culicoides chiopterus and Culicoides dewulfi from bovine dung

•Cowpats containing Culicoides larvae were frozen at different temperatures.•Emergence of Culicoides from frozen and non-frozen subsamples was compared.•No individuals of C. dewulfi survived freezing.•Some individuals of C. chiopterus survived freezing at −18 °C, but not at −21 °C. The emergence of Culicoides chiopterus (Meigen), 1830 and C. dewulfi Goetghebuer, 1936 (Diptera: Ceratopogonidae) from cowpats in northwestern Germany was investigated. In order to investigate the survival of both species at low temperatures, cowpat subsamples were frozen for 48h at −18 and −21°C. Emergence from frozen and non-frozen samples was compared. The number of emerging adults of C. chiopterus from samples frozen at −18°C was greatly reduced and no emergence was observed from samples frozen at −21°C. No adult C. dewulfi emerged from frozen samples, suggesting this species is less resistant to these temperatures, compared to C. chiopterus.