Orius niger

Most of the Orius bugs I've found have been females which can be very tricky to identify. This one is apparently a common species but is particularly difficult to tell from Orius laevigatus which is also supposed to be common.

This male was found by suction. When in liquid, the paramere is quite difficult to view at the orientation shown in the key as it doesn't lie flat that way up. It's probably not entirely necessary to view it that way up as you can see the single flagellum from the other way up, but this being my first I wanted to check it carefully. The first four photos of the paramere below show various orientations. While processing my photos I noticed that the one that was closest to the correct way round seemed to show a slight knob at the base of where the double flagellum would be on laevigatus and I wondered if it was possible that in fact it was a laevigatus but that one part of the double flagellum had broken off.

To resolve this I decided I needed a better look at it at the correct orientation so set it in euparal on a slide. At high magnification I could see that this small projection was smooth and rounded, so it did not look like it was the site of a breakage. Moreover although the key doesn't refer to any other differences in the paramere, there are three other differences illustrated: 1) the flagellum is longer on niger, clearly exceeding the paramere; 2) the tip of the flagellum is bent up on niger and 3) there is a thorn on the side of the paramere on niger just beyond the base of the flagellum. None of these differences were visible on my earlier photo of laevigatus paramere but all three were present on this individual (and on a photo of niger paramere I found on the internet), so on that basis I am satisfied that this is indeed niger.

male Orius niger showing pronotum and paramere (4 orientations before setting and then 3 focuses/zooms set in euparal), Wendling Beck Environment Project (Norfolk, UK), 30th July 2025

This female was found with the male. I don't know for sure whether laevigatus can sometimes occur alongside niger, but I'm guessing that it's more likely (much more likely?) to be another niger. Supporting this ID the mid tibia are dark.

For other Orius species the females' copulatory tube can be helpful but the Kirby key doesn't mention this for leavigatus/niger. I examined it on this one and another found by suction at a different site the same day (see below), but it differed signficantly between the two specimens. I suppose it's plausible that one or other was in fact a laevigatus despite both specimens looking extremely similar to one another in leg and wing colour but different from a laevigatus examined recently, but I suspect that the copulatory tube simply isn't a reliable way of separating these two and that's why it isn't mentioned in the key. It will be interesting to examine more though.

female Orius laevigatus showing pronotum and copulatory tube, Wendling Beck Environment Project (Norfolk, UK), 30th July 2025

This was the other one found by suction the same day but at a different site (within the same project area). It had long hairs in three of the four corners of the pronotum. I initially suspected that as the copulatory tube was so different it might be laevigatus (assuming the last one was indeed niger), but after comparing the specimens with a laevigatus, and confirming the darkness of the legs (including the mid tibia) I think this one was another niger. On this one the copulatory tube had a large round dark blob close to one end of the sclerotised tube, but on the previous one the dark blob was not so large and positioned nearer the middle of the sclerotised section of tube, and also seemed to have a narrow tube emerging from it.

female Orius niger showing pronotum and copulatory tube, Wendling Beck Environment Project (Norfolk, UK), 30th July 2025