Bombylius_egg_ejection 290310_1504

Animation (from a film) 5X retarded

Females of the bee fly Bombylius major are shooting eggs into nest entrances of solitary bees or other holes. The female is hovering near a hole and at some moment the distance will be decreased in an oscillatory way. At last, after two or three periods of oscillation, the egg will be disposed with a swing of the abdomen.

Bombylius_egg_290310_1504_anim_detail

Animation of the swing 20X retarded

Click here for more information on the egg shot.

On one occasion a female bee fly was shooting eggs in the gap between a shoe and sandy soil. The hovering behaviour has been filmed with 300 frames/s and with low resolution. A small part of the film is given here. The film is 10 times retarded in comparison with reality.  The bee fly and its shadow are visible. The shadow is the rightmost dark patch.

 

The distance between the head of the female and the rim of the shoe has been measured. The distance (in cm) as a function of time is given here.

Bombylius_shoe_distance_new

Probably the female is shooting an egg when the distance is a minimum. In the figure this does occur five times at regular intervals of 2.6 s. The last minimum is an exception in several aspects. The minimum is smaller and occurs a little later. The regularity of this behaviour is suggesting the possibility of modelling. Click here for more information on modelling.

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