Again, while photographing plants for a personal identification guide, I noticed there is much more going on in the photograph than plant identification.
I wonder what these flies are doing on this Echinodorus paniculatus flower. There is a pair for each petal; are they a breeding pair? If so, will they lay eggs and form a gull or otherwise use the Echinodorus has habitat/food? Are they simply attracted to the white?
Looks to me like a lek. It is either that or a resource defense system. If they are Drosophilidae, they are unlikely to lay on a live flower. They are likely to feed on nectar, if it is there and also may like a little pollen now and then.
Awesome. Do you think the lek (if it is one) would generally be performed on this plant specifically, or other surfaces? How would I test whether it’s a lek or not?