Hawk moth

[Marek Michalski]

Hello !!!

Yesterday I was observing a male of hawk-moth Sphinx ligustri (I don't
know english name, it's large moth (wingspan about 10 cm ),feeding on
Fraxinus sp. and other plants. It was flying (rather hovering) in
plastic box and I noticed, that it was opening it's genitalia, quite
large plates (5-6 mm long), covered with hair. I have a question:
- what is the aim of this behaviour ?
I have three hypotheses:
1)spreading of some scent (male feromones ?) 
2)steering
3)feeling of delicate air turbulations

regards,
Marek
Uniwersity of Lodz, Poland.