Diptera for the Desperate

Recently I wrote about buying a new camera which required some practice, but after a few days of household items such as pencils and peppercorns, I was desperate for some insects to photograph. My first outing immediately after the snow drew a complete blank, so I had to wait a couple of days for it to warm up before bothering the Ivy in the garden. 

As luck would have it, the very first thing I found turned out to be Dioxyna bidentis, the Bur-marigold Fly. This turned out to be the first record of this species for VC55. Even odder, there's no Bur-marigold around here, but some research told me that the larvae of this species develop in the flower heads of a range of Asteraceae. Here, I suspect that's my carefully cultivated Ragwort (at least, what survives annual decimation by the Cinnabar Moth larvae). 

This odd coincidence makes me wonder what would happen if Jennifer Owen were to repeat her 30 year study - how different would the results be?

 

What *another* camera? Part 2: All out on OM

This is a long and detailed post about photography (macrophotography specifically), you can skip this if you're not interested. 

A year ago I bought an Olympus TG-6 camera for macro photography (What *another* camera? Olympus TG-6 review). This pocket camera has turned out to be a very good buy and I've used it more and more, often in preference to my full Sony macrophotography setup due to convenience. It's the first "Olympus" camera I've ever owned, although Olympus cameras ceased to exist a few years ago and the rights were bought by an entirely new company, OM Systems (but if you say OM to non-photographers you get blank looks, so people still call them Olympus - don't tell the lawyers). Over the last year OM kit has gone from strength to strength, particularly in macrophotography, while Sony has dropped the ball to some extent and is now about the only camera company not to introduce in-camera focus stacking. This is a shame as I've got a big investment in Sony cameras but I've finally given up waiting. 

The Technical Bit: Digital cameras with 35mm sensors are referred to as full frame (the same size as photographic film). As sensors improved, a new smaller sensor format emerged, APS-C. The advantage of these smaller sensors is that the cameras, and in particular the lenses, can be smaller and lighter. An even smaller format, micro four thirds, was released by Olympus and Panasonic nearly 20 years ago, allowing even smaller and lighter systems. There is a price to pay. Smaller sensors are less efficient at light gathering than big sensors and so micro four thirds cameras are light hungry.

As I get older (don't tell anyone) equipment weight becomes a more important consideration for me, although this is secondary to the value of in-camera focus stacking, which a year with the TG-6 has convinced me about. The OM flagship system is the OM-1 with the M.Zuiko Digital ED 90mm f3.5 Macro IS PRO lens, and macro photographers are achieving stunning results with this, but for me it has two problems. My equipment-buying philosophy is to buy good condition used kit from reliable resellers, generally one or two models down from the lastest top of the line models. This generally costs a third to half the price of the latest shiny kit and has served me well over the years. The 90mm macro lens isn't generally available second hand yet and a new OM-1/90mm setup is three thousand quid. No. There's an even bigger (literally) problem. The OM-1/90mm setup is almost the same size and weight as my Sony system, so the only advantage is the focus stacking. 

So I bought a used OM-5 and M.Zuiko Digital ED 60mm F2.8 Macro lens. The price was much more reasonable and the weight (610g) is half the weight of my Sony kit (1077g). Coming from the Sony FE 90mm F2.8 Macro lens the OM 60mm feels like a toy, but certainly doesn't behave like one. Inevitably, having changed manufacturers, there were all sorts of extra bits I had to buy - batteries, filters, etc. This was expected, but then I hit a problem. My Godox flash (Sony version) didn't work with the OM-5. I wasn't sure about this but sadly these things all have proprietary fittings. As I said, micro four thirds sensors are light hungry, macrophotography even more so, thus a new OM-compatible flash was an unavoidable extra expense. 

All photographers moan about camera menu systems but after a year with the TG-6 I thought I'd be OK with the switch to the OM-5. In fact, it proved to be a pretty steep learning curve and I'm still dialling in on the best settings for me. The 60mm macro lens is pretty good, although for my needs it lacks a little bit of magnification so I'm pushing it further with some add-ons. The micro four thirds sensor imaging area is 17.3x13mm and the maximum magnification of the 60mm lens is 1:1. Adding a Raynox DCR150 lens gives 1:1.3 magnification (13mm long subject area) and a Raynox DCR250 gives 1:1.5 (11mm subject area). I can increase this more with extension tubes. I've still got a way to go practicing with this new setup but I'm getting there. It seems to work (click for larger image):

 One very important caveat:

If you went to a Michelin-starred restaurant and ate the most delicious meal of your life, would you ask the chef ,"What oven do you use"?

 

Ants - Naturalists Handbook

I'll be honest, Hymenoptera give me the heebie jeebies, but ants surely have to be the most fascinating group of insects which have yet evolved. I'm naturally drawn to under-recorded groups and ants are very much neglected in VC55. With only 61 species occurring in Britain they are also a manageable size (compared to say, Ichneumons). But I must resist, I've made a deal with myself that I'll get to ants after I've sorted out aphids (but don't hold your breath!). When the day comes I won't be able to do better than Gary Skinner and Andrew Jarman's updated Ants book. In fact, I could splurge a lot of money on the Naturalists Handbooks Series ... but I must resist! 

Skinner, G.J. & Jarman, A.P. (2025) Ants (Naturalists Handbooks Vol. 24). Pelagic Publishing Ltd. ISBN 9781784273040 https://pelagicpublishing.com/collections/naturalists-handbooks/products/ants-second-edition

 

Entomology Journal - December 2024

Not a lot of entomology for me this month, I've been mostly thinking back on this year as well forward to 2025.

I've never kept a regular journal for a whole year before so this has been an interesting exercise. While it's nice to be able to recap the year easily, it hasn't been an easy process for me. I'm not a natural diarist and this journal has been rather selective. To be able to keep this up I need to make some changes, and from January I won't be writing a full journal each month, but I do want to continue on a more advanced ad hoc basis, so in future months it will be more of a digest than a diary. 

FIT Count Summary 2024 

Low carbon biological recording - and remembering sunny afternoons in the garden. 

Spider Surprise

First VC55 record for the Ray Spider, Theridiosoma gemmosum. 

My Journal, December 2024

03.xii.2024
A local trip to the Attenborough Arboretum. Not much to be found but lots of Giant Willow Aphids. After some effort I did manage to confirm a record of Mycena calvularis on a Willow trunk, a good result for my rusty mycology.

 
09.xii.2024
Weather pretty bad, so a week of microscope work catching up on the summer backlog.

 
13.xii.2024
LRES first ever online meeting on Aquatic Bugs seemed to be well received by guests. The members were possibly less keen on this format.

 
17.xii.2024
Went on a secret mission to a secret location to collect a secret species for a secret project! Sorry, but I hope to have an exciting update in 2025!

 
29.xii.2024
After two weeks of the gloomy weather I can remember, finally a pink dawn and some sunshine. With the days getting longer, a prospect of hope on the horizon for entomology in the year to come.

Read previous Journal entries

  

FIT Count Summary 2024

The UK Pollinator Monitoring Scheme (UK PoMS) launched FIT Counts (Flower-Insect Timed Counts) in the UK several years ago. At the time, I decided not to bother. This year, with the moth trap in my suburban garden not justifying the electricity to run it (other than to document the disastrous local decline in flying insect numbers this year), FIT Counts seemed much more attractive. For one thing, FIT COUNTS are a very low carbon way of recording - in good weather, spend ten minutes watching flowers and insects in your garden or local park, then upload the results via a mobile phone app or the website. I'm usually disappointed by big citizen science projects, which tend towards engagement rather than useful data, but the FIT Count methodology is geared towards long term monitoring which is desperately needed. 

UK POMS has just sent all the recorders an end of year summary - short version: another record year for FIT Counts. My own effort is a sad four sessions, but I'm looking forward to the start of the FIT Count season (1st April - 30th September) and making a better effort next year. With 2024 virtually certain to be the warmest year ever and the first year to exceed 1.5°C above pre-industrial levels, this sort of data becomes ever more important, as does gathering it without getting in your car and driving off to get it. The two most important groups of pollinators, bees and flies are both vulnerable to climate change between these two major groups of pollinators, with flies seemingly being more at risk. Even 10 minutes standing watching your local insects can help. How hard can that be? 

Critical thermal maxima differ between groups of insect pollinators and their foraging times: Implications for their responses to climate change. Journal of Melittology, (122), 2024.

https://journals.ku.edu/melittology/article/view/22505

 

Spider Surprise

A cold December day, half the countryside under water - what else to do but huddle over a nice warm microscope catching up with samples from the summer bulge when it is just impossible to keep up. In this case, a streamside vacuum sample from September. It started off in a humdrum way, knee deep in Bathyphantes gracilis and Tenuiphantes tenuis, but then ... a tiny speck of a spider turned out to be the Ray Spider, Theridiosoma gemmosum. I've never seen this species before and it's the first record for VC55 as well as a considerable range expansion. Fortunately it's a pretty unmistakable species (once you look close enough), which is lucky as this was an immature male - not surprising since September is past the peak for this species. A nice surprise on a winter's afternoon.

Entomology Journal - November 2024

Winter has arrived, entomology slows down. 

Bluesky

There are social media people and non-social media people. If you're one of the latter you might want to read on - old dogs and news tricks, etc. I had a long history on the Twitter social network, including academic publications. At first I couldn't get my head around Twitter - how could something so trivial be of value? The value of course is in the conversations which happen in the network. I fell out of love with Twitter some time ago, but couldn't face leaving. In the end, I didn't leave Twitter, it left me - sometime before it became "X". I haven't missed it, solely because I now have a new and much better network. Naturalists (and other communities) have flocked to BlueSky - https://bsky.app/ - and it's already helped me with identifications, as well as simply giving a sense of belonging. I hope you will join me there and become part of my network - https://bsky.app/profile/ajcann.bsky.social  If you need any help getting started, just ask. If you would like to know more about BlueSky, there's a good article in Nature here. 

Pygmy Backswimmer, Giant Headache?

Although small, the Pygmy Backswimmer, Plea minutissima, was always an easy tick - there's nothing else like it. Well now there is. A new paper describes another species (Plea cryptica sp. nov.) found across Europe, but not so far in the UK. It's highly improbable that it's not here, so now we've got to check them all - not an easy task. Raupach, M.J., Charzinski, N., Villastrigo, A. et al. The discovery of an overseen pygmy backswimmer in Europe (Heteroptera, Nepomorpha, Pleidae). Sci Rep 14, 28139 (2024)

Also:

• Parasitic Mites on Corixids
• Olympus TG-6 Update

My Journal, November 2024

01.xi.2024

Gave the moth trap a run but only three Light Brown Apple Moths, zero bycatch. Doesn't justify the electricity so I think that's it for me now until the spring.

02.11.2024

A trip to Loddington to sieve the leaf litter. Nothing amazing found but nice to be out in spite of the drizzle.

05.xi.2024

Visited Loughborough Cemetery to check the Mistletoe. Little found sadly.

12.xi.2024

Took a trip to Bardon Hill to sift some leaf little. Arthropods were hard to find, but nice to be out.

16.xi.2024

A lovely visit to Launde Park Wood. Although bugs were in short supply I was happy to sit in the sun and drink coffee. The highlight of the trip turned out to be tiny yellow fungus cups on a dead log. I assumed these were Lemon Disco, Bisporella citrina, but one of my Bluesky friends pointed out to me that the adjacent black fruiting bodies are pyrenomycete fungi, probably Rosellinia species.  This means the yellow one is  actually Sulphur Disco (Calycina claroflava, formerly Bisporella sulfurina), which parasitises the mycelium of pyrenomycetes.  

19.xi.2024

Winter arrives, bringing snow. Bugs are huddled up.

22.xi.2024

I ventured out to Billesdon to try to find some aquatic bugs.  Plenty of snow on the ground and I had to break the 1cm thick ice on the pool. Underneath, I found lots of Notonecta viridis and also abundant Corixids happily overwintering and unbothered by the cold. Among the species I found was a specimen of Callicorixa praeusta parasitised by  the larva of a Hydrachna water mite (link above). 

26.xi.2024

A rare sunny day. The Winter Gnats are dancing. I've tried to net these in the past to check the species but they always elude my clumsy efforts. Took a trip to Brocks Hill to take advantage of the sunshine but very few invertebrates around. A single Drymus reyei under a log was a nice find.

Read previous Journal entries

  

More Olympus TG-6 Tomfoolery

Recently I wrote about using the in-camera focus stacking on the Olympus TG-6 for macro photography, today I thought I'd push it as hard as I can to test the limits of this camera. The first idea was to create multiple inage stacks (by pressing the shutter repeatedly) and then stack them all together using Helicon Focus. This was ... partly successful. My first test subject was ... a pencil. I made 9 image stacks then fed them into Helicon. 

The problem is that no matter how hard I tried I couldn't keep the camera from moving between stacks - any movement at all degrades the final Helicon stack. The best I managed was three aligned stacks (3x15=45 images), which is the pencil you see above. 

I then moved on to wildlife. With a small spider (Diplostyla concolor), about the same size as the pencil tip in the above image, I couldn't manage to get multiple stacks without camera movement - this was the best, a single set of 15 images. 

When I tried with the bug Drymus ryei, the same thing happened, but the result still wasn't bad. So it was time for the big head to head: Olympus TG-6 versus Sony a6500 with Sony 90mm macro lens - a camera with a 12MP sensor versus a setup with a 24MP sensor costing four times as much. 

Olympus TG-6

Sony a6500

And the result was ... well the Sony is better (duuh) (click on the photos for larger images), but the TG-6 gives it a run for its money, costs a fraction of the price and fits in a shirt pocket. Good job TG-6! 

I could of course carry on with this nonsense by putting the TG-6 on a tripod and using the Olympus OI.Share app to remote trigger the camera. But that, I'm sure you agree, would just be silly...

 

Parasitic Mites on Corixids

I ventured out recently, broke the centimetre-thick ice on a local pool and underneath, found abundant Corixids happily over wintering and unbothered by the cold. Among the species I found was this specimen of Callicorixa praeusta: 

You may notice the small red object protruding from the rear end. Looking closely, this was a mite attached to the bug rather than part of the Corixid: 

Phoretic (hitchhiker) mites are not uncommon on Arachnids but a little research told me that this was in fact the larva of a Hydrachna water mite.

These larvae are actually parasitic rather than phoretic, feeding on the haemolymph of the Corixid. There is some interesting information here: http://coo.fieldofscience.com/2014/12/hunter-balls-hydracha-water-mites.html  They are not as common on Corixids as on some other Arachnids and I have no idea how much harm they inflict on the host. 

Great fleas have little fleas upon their backs to bite 'em,

And little fleas have lesser fleas, and so ad infinitum.

Augustus De Morgan