Entomology Update - January 2026

After a freezing start, January was mostly ... wet, limiting entomology opportunities. 

Phone-based retirement

The weather hasn't helped but are we all spending too much time on our phones? 

An odd spot

The ladybirds appear to be plotting something, I'm not sure what they are up to. 

The Mysteries of the Metapleuron

It would be quite handy to have a metapleuron. 

Oligometry

The twisted tale of a wonky antenna. 

Two videos: 

Macrophotography Methods

and: 

Getting the most from your Olympus TG camera

 

Events 

• Leafhoppers & Allies: identification, ecology and recording - Alan Stewart
• VC55 County Recorder Conference

News from Elsewhere

Tiny forests ... are an (expensive) con

But don't take my word for it: Tiny forests, huge claims: The evidence gap behind the Miyawaki method for forest restoration. Journal of Applied Ecology, e70242. https://doi.org/10.1111/1365-2664.70242

It's the pits

A new paper shows that the sensory pits on the cuticle of planthopper nymphs (Fulgoromorpha) sense electric fields.

Read previous updates

Latest photos

Oligometry

In Peritrechus, the structure of the antennae is an important diagnostic character. In Peritrechus geniculatus, ant3 is as thick or thicker than ant1, whereas in the other very similar species it is thinner. This recent specimen was missing the left ant4 but still identifiable as P. geniculatus. Then Jim Flanagan pointed out something odd to me. Maybe the left ant4 never got lost - it just didn't grow? The key is that the left ant2 is longer than the right - this is called oligometry and is frequent in Lygaeidae. Oligometry usually results in one of the antennae having three segments (it can also affect both antennae and then it is known as bilateral oligometry). It is thought to be caused during late development phase but precise reasons behind this deformation are not well known.

 

 

The Mysteries of the Metapleuron

I've always found Nysius to be a difficult genus to identify, apart from the obviously hairy N. huttoni. I turned up a few at the weekend but this time I used the key published by by Dolling, Het News, Issue 2, Autumn 2003. This turned out to be much easier than the other keys, and in the blink of an eye I had this one down to a species pair - N. graminicola vs. N. senecionis. The hind tarsi indicated which of these two it was, but to confirm I had to check the metapleuron, which confirmed that this was Nysius senecionis. 

Which raises the question - what the heck is a metapleuron? In Nysius the metapleuron is the lateral sclerite of the third thoracic segment and is the primary platform for the metathoracic scent gland (MTG) system. It consists of:

• The ostiole: an opening on the metapleuron through which the MTG reservoir empties its contents.
• The peritreme: a specialized cuticular structure (often shaped like an auricle or spout) that surrounds the ostiole. This directs the liquid secretion away from the body and onto the evaporatorium.
• The evaporatorium (or matt area): a distinct, non-glossy region of the metapleuron characterized by a highly micro-sculptured, "mushroom-like" or reticulated cuticle which increases the surface area significantly, allowing the defensive fluid to spread rapidly and evaporate (volatilize) almost instantly. This creates a "scent cloud" that deters predators before they can make physical contact.

The most important physiological role of the metapleuron is the dispersal of repellent defence chemicals. An additional role is in pheromone communication, acting as a broadcast structure for alarm, aggregation and sex pheromones. The specialized cuticle of the metapleuron evaporative area also prevents defensive secretions from being absorbed back into the insect's own underlying tissues.

I don't know about you, but it seems like a metapleuron might come in quite useful.

 

An odd spot

I made my first ladybird records of the year yesterday. Since December, through all the rain, frost and snow of January, through Storm Gorblimey, these two 7 Spot Ladybirds, Coccinella septempunctata, (which had a good year), had been huddled up on a Yew planted a few years ago precisely to give overwintering shelter for invertebrates. But rather than seeking shelter they were clamped to the tip of a branch in the most exposed spot possible. I was starting to wonder if they were alive, or semi-alive (parasitised), but when I took their photo (without touching or disturbing them as far as possible), they wandered off in a huff and settled down again a few inches away. 

In the afternoon, clearing out the garden nestboxes, I found a 2 Spot Ladybird safe and warm in a cozy woodcrete winter home. Sadly, I did have to evict this one in order to clean out the box, but yesterday was warmer so it will be fine. 

Phone-based retirement

The Atlantic

I don't write about sociology but I am interested in the collapse of social capital, especially as it relates to engagement with natural history. In the US there has been a lot of discussion recently about "phone-based retirement" - retired people are spending more time on (mobile) screens, with less engagement in traditional activities (such as stitting in chilly church halls listening to natural history talks). In his book Bowling Alone, sociologist Robert Putnam used the collapse of US 10 pin bowling leagues to illustrate the decline of social capital. While Putnam was describing a pre-Internet society, the same trends have continued and probably accelerated (Covid or no Covid). Putnam says he doesn't know the "answer" to this. Which is good, because neither do I. Currently it's hard to see how this trend could be reversed. For a mere £9 a year I can "participate" in all of Cambridge Natural History Society's talks online via Zoom. That, together with the super output of the Biological Recording Company, is in some ways an amazing prospect; and in others, thoroughly depressing. 

It's the pits

A new paper shows that the sensory pits on the cuticle of planthopper nymphs (Fulgoromorpha) do not respond to sound, ultrasound, mechanical stimulation, temperature changes, or magnetic fields. They do, however, respond to stimulation with very low intensity electric fields. This, together with the arrangement of these special sensory structures on the body surface of planthoppers, imply that these sensory organs perceive electric fields in the environment. The authors suggest that this sense may help the bugs to avoid predators or parasitoids. This finding also corresponds with recently published observations for treehoppers (Membracidae), where the horn-like extensions of the pronotum contain similar sensory pits. 

Electrosensitivity in planthoppers (Insecta: Hemiptera: Auchenorrhyncha: Fulgoromorpha). (2026) Journal of Comparative Physiology A, 1-13. https://doi.org/10.1007/s00359-025-01790-1