Saturday, 22 February 2014

Trioza urticae

In yesterday's catch in the water trap was a female of Trioza urticae, which means that two of the four common members of family Triozidae have turned up in my garden in February.  There are 19 species on the British list in this family in four genera.  Of these six are rare or based on very few records and six are uncommon.  Of the remaining seven, four are locally common and three are common to very common.  One of the remaining common species is associated with oaks and the other with willows, so the latter could turn up with the ornamental willows in the garden.  There are no oaks particularly nearby. 

Today's image shows Lauritrioza alacris and Trioza urticae next to one another.  They differ in particular in the length of the front vein which goes past the Y-fork in the second vein in Trioza and ends well short of the fork in Lauritrioza.  Below the eyes there are two triangular projections known as the genal cones.  These are pale in Lauritrioza and black in Trioza.  Seen side by side a number of other differences are apparent.  Lauritrioza alacris is associated with bay trees (scientific name Laurus nobilis - hence the insect's name).  Trioza urticae is found on nettles (Urtica dioica -again giving the insect its name)

Omitted to mention that the frogs were in the pond well over a week earlier this year although they have not begun spawning yet.  This year it there were sixteen in the pond on the 19th February; last year it was the first week of March before any turned up.


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