Chasing behaviour of male housefly (Musca)

Chasing behavior experiments and analyses of male housefly (Musca) under a condition of free flight were reported. The preliminary results are as follows: 1. The horizontal turning angular velocity dF₁ (t_º) of male chasing fly linearly depands on the horizontal error angle T₁ (t_º - ∠t) of female leading fly. If the female leading fly is located in front visual field the slope of regression line is about 37, otherwise the slope of regression line is about 6. 7. 2. The pitch angular velocitv dF₂ (t_º) depends on the pitch error angle T₂ (t_º - ∠t), too. There is a linear relation between the two variables in a wide range. 3. In chasing behavior of male fly, the histogram of frequency number N₁ of horizontal error angle T₁ presents almost symmetric distribution in which a peak locates at zero degree, but at the peak of histogram of frequency number N₂ of pitch error angle T₂ locates about 20 degrees. 4. Male chasing fly controls its velocity of flight according to the distance change dD between the two flies and stereo-error angle. If the female leading fly is located in front of visual field the values of dD are usually negative, it means that the two flies get closer and the acceleration of male chasing fly linearly depends on the distance change dD. If the female leading fly is located in the back of the visual field the values of dD are usually positive, it means that the distance between the two flies increases. 5. The delay between input variables and response variables attributes to the processing time of neural circuit, the response time of servo-actuator and movement inertia of the fly.