Nocturnal windborne migration of ground beetles, particularly Pseudoophonus griseus (Coleoptera: Carabidae), in China
1 A network of light-traps, an aerial net carried by kytoon (balloon) and two entomological radars were used to investigate whether ground beetles migrate nocturnally through China. The network-wide, simultaneous sudden increase in light trap catches, and after subsequent decrease, indicated a seasonal long-distance night migration of ground beetles, with Pseudoophonus griseus (Panzer) predominant, in August.
2 Aerial net trapping indicated that carabids were able to ascend to altitudes of at least 200 m and become windborne. Radar observations indicated that the migratory beetles formed high-density layer concentrations at approximately 200–300 m.
3 These concentrations were coincident with the top of the temperature inversion and a wind speed maximum, which suggested that the carabids tended to select warm, fast moving air for their long-distance migration.
4 The ground beetles orientated and displaced towards the downwind direction in southerly winds. Their air speed decreased as the tailwind increased and, thus, migrating beetles appeared to be conserving energy.
5 The mean ± SD displacement speed (ground speed) and air speed were 6.85 ± 1.73 m/s (n= 172) and 4.45 ± 1.54 m/s (n= 172), respectively. The duration of flight, estimated from the variation in area density derived from radar data, was approximately 9–10 h, indicating that the beetles might migrate hundreds of kilometres in a single flight.
Document Type: Research Article
Affiliations: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100094, P. R. China
Publication date: 2007-05-01