Thread subject: Diptera.info :: Stomorhina

Posted by Tony Irwin on 04-08-2006 23:29
#1

This is a rather poor picture of a male Stomorhina lunata which my friend Stuart Paston caught in Norfolk, England a few days ago. I have enlarged the head to show the characteristic produced mouth margin and the arista which only has dorsal hairs.
In Britain this is a very scarce vagrant. There has recently been a large influx of dragonflies and moths from mainland Europe, and this Stomorhina capture is probably part of the same invasion.
We want to find out what the status of this species is at present. Has anyone in Europe caught it away from its usual localities this year?

Posted by Kahis on 05-08-2006 00:12
#2

A great find indeed!

Stomorhina lunata has been found in Finland only once, nearly 100 years ago. The record is from the University botanical gardens in Helsinki. Given the location they may well be imports, brought to our country with some exotic plants, but migration this far north is by no means impossible.

The Baltic sea forms a effective migration pathway for various insects. In the fall, when the sea is warm but air above the land much colder, the vagrants and migrants land 'en masse' on the south coast and in the archipelago - a process well documented for macrolepidoptera. Only the strongest regular migrants (such as Vanessa atalanta and Eristanis tenax) can regularly break through the border defenses :D

Posted by Tony Irwin on 05-08-2006 01:46
#3

Thanks for the information, Kahis.
Perhaps you will be lucky and be able to report a second specimen from Finland! :D

Posted by Tony Irwin on 05-08-2006 16:01
#4

I have just heard from Peter Chandler that a Stomorhina was caught by Chris Spilling on the Isle of Wight (Hampshire, England) last autumn.

Posted by Zeegers on 05-08-2006 17:56
#5

Hi Tony


The ID is correct.
IN the Netherlands Stomorhina lunata is now present for at least five years. So I'm not too surprised you have it as well.
Best time of the year is autumn, till late in october !


Theo Zeegers

Posted by Tony Irwin on 05-08-2006 19:08
#6

Hi Theo
Thanks for the information. I assume that these Netherlands records are all migrants, or is there a possibility that it has found a suitable host there?

Posted by Zeegers on 06-08-2006 12:55
#7

It is my strong believe that the species has settled in Netherlands.
A similar situation occurred in England in the 1940ies or 50ies, well documented (if you are not familiar with the reference, I can look it up for you).
There is no direct proof for my believe.
However, it is highly unlikely that a species does not reach one country in 70 years, and then reaches it 5 times on a row independently.
Simply a matter of statistics.

A few years ago, Stomorhina was not even rare in september in The Netherlands. However, the number (of records) are currently decreasing.

Theo