Lygus Identification for Dummies (like me)

For some time I have been unhappy about my ability to determine the species of certain Lygus specimens. A typical Lygus pratensis is easy - based on "shinyness" (pubescence) of the elytra and markings on the scutellum. (Having said which, the extent of seasonal colour variation in L. pratensis has only just dawned on me - not quite as extreme as Palomena prasina but not far off.) Likewise, a typical Lygus rugulipennis is easy - dull (pubescent) appearance. However, not all specimens are typical. A short time ago I found an atypical Lygus - quite shiny with Lygus wagneri-like markings on the scutellum: 

Such specimens are a problem. I find Nau's illustrations of the pubescence of the corium unhelpful (and he acknowledges the difficulty in distinguishing between certain specimens of L. pratensis and L. wagneri - Nau, B. (2004) Identification of plantbugs of the genus Lygus in Britain. Het News Issue 3, p11). 

Namyatova et al (2022) published a study of Lygus species including both habitus characters and male reproductive anatomy (Namyatova, A.A. Tyts, V.D. & Bolshakova, D.S. (2022) Identification and delimitation of the trans-Palearctic Lygus species (Insecta: Heteroptera: Miridae) using integrative approach. Insect Systematics & Evolution, 54(2), 146-192). According to Namyatova et al the overlap between L. pratensis and L. wagneri is explained by the fact that they are synonymous based on DNA homology, something which fits with observations of habitus. Leaving taxonomy issues to one side, the drawings of the spicule and the presence or absence of teeth on the right side of the small lobe of the vesica make distinguishing Lygus species (backed up by habitus) relatively straightforward. Although only males can be determined and dissection is required, this is at least a definite way of identifying atypical specimens with certainty. 

The issue now is that I have yet to encounter L. wagneri! Although we do have one record of this species in VC55 I am not convinced that it occurs here. However I am confident that if I do ever find a male L. wagneri I will be able to identify it with certainty! 

 

 

 

Entomology Journal - September 2024

Limited opportunities for entomology this month, and further truncated by bad weather later. 

 

My Journal, September 2024

10.ix.2024 

Finally managed to run the moth trap after missing the whole of August. 13/7 not too bad considering the trap blew over! The highlight was a nice Small Ranunculus, Hecatera dysodea. Followed on with more seasonal garden wrangling before the rain. 

12.ix.2024 

A very enjoyable evening at the first LRES meeting of the new season. I was able to pick up specimens from several people to check. 

13.ix.2024 

Another very cold night, the coldest September night for five years according to the Met Office. Spent some time checking the contents of a flight interceptor trap I was asked to look at. 

16.ix.2024 

A lovely autumn day, sat in the garden and watched a successful mating of Garden Spiders. Identified some of the bugs I had been given at LRES. 

17.ix.2024 

18/9 in the moth trap, not bad for a full moon, and while it was warm when the trap went on it got down to 6C in the early hours. Spent the rest of the day tackling the wildwood in the garden. The evening was the AGM for the local wildlife group, with a talk on urban botany in Leicester from Russell Parry - whose thought-provoking talk made me dream of electric sheep: https://ajcarthropoda.blogspot.com/2024/09/dreaming-of-electric-sheep.html

18.ix.2024 

A short local walk on what turned into a nice afternoon. Lots of Common Darters ovipositing in the Washbrook, and plenty of Ivy Bees - the numbers are going up steadily year by year. 

21.ix.2024 

A lovely morning which I used to play dodge the cows along the Soar at Croft Pasture. Using the vacuum sampler turned up a good range of invertebrates. Fortunately home again before the apocalyptic thunderstorms in the afternoon. 

22.ix.2024 

A biblical deluge to greet the Autumn Equinox brought the local frogs out, and with them the first "star jelly" of the season. 

23.ix.2024 

Spent a very wet day indoors working on Lygus specimens. Some progress made but I need more specimens! 

25.ix.2024 

Only 10/5 moths in the trap after a chilly night, so the highlight was a rather lovely Caddisfly, the Cinnamon Sedge, Limnephilus marmoratus, a new species for me. Attempted to hack back the vegetation in the garden ponds to restore some order. 

28.ix.2024 

Took advantage of a sunny afternoon to spend half an hour in Knighton Park beating trees for insects. My finds were down no doubt because of the recent heavy rain but it was good to get back out again in the sunshine for an hour. In the garden a Hawker dragonfly was interested in the newly cleared pond.

29.ix.2024 

A rather chilly outing to Billesdon with the dipnet and the beating tray. The pool produced a range of Corixids and I found more insects on the trees. Home before the rain started again. Looking at a few days on the microscope now until the rain stops. 

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