The search for the European Stalk-eyed Fly

Stalk-eyed Fly, Achias sp., male (Australia)

Stalk-eyed flies (Diopsidae) are fascinating insects. Males have their eyes on long stalks and the longer the stalks, the more attractive they are for females. It is quite unpractical to have such 'long eyes' and it is thought that when you can deal with such unpractical eyes, you must be quite healthy and therefore you are attractive when you have longer eyes (handicap principle).
When I heard that an European member of this fly family, Sphyracephala europaea, lives in Hungary and we had plans to visit Hungary on a future holiday anyway, I decided to go and search for it.

There is not much know about this species, because only few people had the luck to find one in the 20 years after it's discovery in 1996. The original article (Papp 1997) and the key to the European fly families by Oosterbroek, as well as several blogs reporting about a lucky find (here and here), do give some basic information.


Sphyracephala europaea lives along waters at shadow-rich places often occurring in large numbers together. These small flies (4 mm) seem to prefer the direct shore of the river. Flies were found from September to November, but also in June. The pictures in the blogs give an additional feel of the habitat of the fly.

We stayed a few days in Mako, south east of Szeged, so that I could search along the river Mures, which s known as one of the places where this fly can be found.

The fluvial forest that I could see from the campsite looks very promising for finding S. europaea or some other rare species. The challenge is to find some open spots, where I can reach the river bank and optimally find some flat shore to search.

The first day after arrival, we decided to rent a bike and get us a decent map of the environment. It is generally the best option to get a local map with detailed bike and hike tracks; the most recent maps are normally sold locally. The alternative with google maps, was not an option anymore, since the internet connection at the campsite was dead. The bike rental worked out well, at a hotel nearby. Arriving at the tourist office, people were very happy with us. Mako has been made more accessible for tourists the past years, with an official tourist office, but apparently hardly tourists. They tried to sell us postcards of Mako. Unfortunately they did not have a detailed map, only road maps just as detailed we already had, not sufficient to identify good places to look for S. europae ... The local bookstore had more maps but not more detailed, and a large pile of the, apparently single type, postcard of Mako.

We set of for a bike trip along the north side of the river. It was an interesting trip over the river dike and enjoying the countryside. Only occasionally there were places where I could reach the shore. Mostly it was without a sandy shore, with the land abruptly ending with a meter downward into the water. It was hard to look for insects here. And as it may not surprise, I was not successful.

The second day, I decided to try the other (south) side of the river. I found a place with a small path only a few meters from the shore, probably for people going fishing.

A place being ecologically very interesting, with many old trees, occasionally flooded and with dense vegetation.


This fluvial forest 'looks like a jungle'.

Soon, I started to see flies. Flies of all sorts...

This is a Black scavenger fly (Sepsidae)


A Stiletto fly (Therevidae)





This could be a Sapromyza sp. (Lauxaniidae) or a Marsh fly (Sciomyzidae)



Probably a Snipe fly (Rhagionidae)



Very hard to tell, a Lance fly (Lonchaeidae)?, a Scuttle fly (Citrago sp., Phoridae)? or Cacoxenus indagator (Drosophildae)?


A Long-legged fly (Dolichopodidae) or a Stretched-foot fly (Tanypezidae)?



These thick long antenna are often indicating that these are Thick-headed flies (Conopidae), but probably these are 'Parasite flies' such as Cylindromyia bicolor (Tachinidae), indicated by the stiff hairs on the body and the red coloring.



A Robber fly (Asilidae), easily recognizable by the deep valley between the eyes.










With >5 cm too large to be a fly. It is an adult of another rarely seen insect group, Antlions (Myrmeleontidae), belonging to the insect order of net-winged insects (Neuroptera); adults are occasionally seen close to river shores, while funnels made by larvae are more commonly seen.



A Scorpion fly (Panorpidae). Not a fly (Diptera) at all, but belonging to the insect order Mecoptera.
Long antenna, long snout and a scorpion tail!

Unfortunately still no sign of a stalk-eyed fly ...


Near the campsite there was a small patch of sandy shore which may be the better habitat.


























The first insect I found was a Pygmy mole cricket (Tridactylidae).




This is Xya variegata, known from the Mures river banks. Quite nice!



 

And what is this?


This may be a shore bug, Saldula sp.




Finally, a small fly!



closer... This patterning is typical for the Genus Anthomyia in the family Root-maggot flies (Anthomyiidae).


Another small fly!

Is this the rare Leiomyza dudai the family Asteiidae, as Walter reports in his blog? Or maybe it is ....


Unfortunately, this day I still found no sign of a stalk eyed fly.


On the third day, we had to leave for our home trip. On the way back, we decided to stop near the river bank of the Mures river, but it was difficult to see on our road map where to stop the car. Our attempt to get close, resulted in a forest hike, that ended 50-100 metres from the river bank, with too dense shrubs to get trough. It was the end of the search.

Alleviating the disappointment, I found this beautiful butterfly:

The common glider - Neptis sappho




And finally, I also could make an acceptable photo of a dragonfly in flight!


I left for home, not with empty hands, but with a sight of the stalk-eyed fly neither. It was a pity, but I did my best. Home again, I finally could do a decent google map investigation with a lot of zooming. I found many additional places that would have been suitable to search! That was a bit depressing conclusion, but I never would have prepared on forehand a map so detailed as would haven been required for this... And to be honest, with probably the main flight period in September to November, I may had been unsuccessful anyway in finding this fly. It was an interesting quest for a fly with many interesting discoveries on the way!
(The fly at the startz