The Effects Of Field Environmental Factors On The Three-dimensional Flight Trajectory Of Pieris Rapae

The small white butterfly,Pieris rapae(L.),is one of the most widespread and most harmful pests in China,with its commonly utilized host plants belonging to the Brassicaceae family.Small whites feed,mate and lay eggs in farmland ecosystems.Understanding the impact of complex and diverse environmental factors on the flight of small white butterfly can provide a theoretical basis for the prevention and more efficient control of this pest.In recent years,with the rapid development of high technology,analyzing insect flight behavior real-time in field conditions became realistic.With two or more digital cameras working parallel we can retrieve information from two different views of the same object and reconstruct it into three-dimensional information.Our experiment used a stereo camera system to record the flight path of the small white butterfly for the first time in its natural environment.This method based on the binocular stereo vision theory enabled us to record3 D trajectories,to calculate flight properties,and to correlate those with measured environmental variables,such as air temperature,relative air humidity,wind direction,wind speed and cauliflower occupancy.Our aim was to investigate how environmental factors or the combination of those will affect the flight path of P.rapae.In order to understand this we recorded flight parameters that can characterize flight paths,such as flightlength,flight speed,flight straightness,average,maximum,and minimum flight height in a field environment.The flight length of the small white butterfly was 5.03±3.18 m,the flight speed was 1.12±0.59 m/s,0.9 ~ 1.3m/s;the flight straightness was 0.84±0.22,there will not be too many diversions during the flight;the average flight height is 0.44±0.34 m.Within the measured temperature range,the flight speed of the small white butterfly decreased with increasing temperature.With the humidity increasing,the flight speed of the small white butterfly increased.With increasing wind speed,the flight speed of the small white butterfly gradually decreased.The wind direction also had an effect on the flight speed of the small white butterfly;when the butterfly flew downwind,the flight distance increased.There was an indication that the average flight height and maximum flight height of the small white butterfly increased with increasing proportion of Brassicaceae in the sampling area,and the effect was statistically significant.This experiment clarified the influence of environmental factors on the 3D flight trajectory of the small white butterfly,and provided a theoretical basis for the prevention and control of the small white butterfly.