#3
Thank you for your reply Jan. The fact that all specimens collected around face are males really lead to "cherchez la femme" explanation. For example, if one collects flies from horse eyes, the vast majority of Musca, Fannia or Hydrotaea are females which feed on tears.
#4
Dear Jan,
today I read your paper with a great interest. Thank you for your kind help.
I also discussed this matter with my friend Dr. Oleg Kosterin (Novosibirsk).
What we have?
1. Male licking presumably salt soil and drinking from presumably brackish pools, while females do not that, are very typical in Lepidoptera (you shortly mentioned it too).
2. Both Drosophylid and Lepidoptera are nectar/sap feeders.
3. You and Domenico Otranto supposed that Amiota & Phortica males produce a large amount of sperm. That is also typical for Lepidoptera.
Oleg offered a new explanation:
A very compact packing a lot of DNA in a lot of sperm nuclei requires a lot of cations like Mg++
Possibly that is why males of
Amiota & Phortica specially need animal secretions, while females do not.