Table 1.

Ethogram of male flies during agonistic encounters

Behavior	Abbr.	Description
Approach	A	One fly advances towards the other; usually offensive
Chasing	Ch	One fly chases after the other; offensive
Courtship associated behaviour	CAB	Courtship elements exhibited towards a male (like licking or copulation attempts)
Doing nothing	DN	No (re)action visible
High-level aggression	HLA	A combination of several aggressive and offensive interactions between flies, including fencing, lunging, head butts, holding, tussling and boxing
Retreat	R	An animal tries to escape from the opponent either by walking, running or flying away; defensive
Tapping	T	A fly extends one leg and touches the body (legs, thorax, abdomen) of the opponent
Wing movements	WM	Includes every silent distinct movements of the wings like wing flick, wing waving, etc., excluding wing threats
Wing movements with sound	WMS	Includes the same movements like WM but they are accompanied by sound (usually structured sound pulses)
Wing threats	WT	Both wings raised to an angle of approx. 45° from the horizontal body axis; offensive when flies are facing each other, defensive if otherwise