The demise(?) of the local natural history society

I was sad to hear of the demise of Hinckley Natural History Society. In my opinion, it is unlikely to be the last. From reports I am hearing, most if not all local societies are struggling with static or falling membership and an ageing demographic. It would be easy - and wrong - to blame lots of things for this. As on the high street, Covid-19 may have provoked an immediate crisis, but in reality it has only accelerated trends which have been in place for some time. It would be even easier to blame "the Internet", but equally wrong, as anyone who has read Robert D. Putnam's 20 year old book Bowling Alone: The Collapse and Revival of American Community can testify. The colonisation of natural history by mass media has not helped. Millions are happy to sit on their sofas and watch the antics of cuddly wildlife on Springwatch, but few are prepared to get off them and drive to a chilly church hall on a February evening, or put their hands in their pockets to pay the annual subscriptions needed to fend off the costs of insurance and venue rental. If you're one of the stalwart band of officer holders of a Natural History Society, the tide of history was against you. The decline of social capital has been linked to the rise of political populism - an interesting theory, if impossible to prove. 

At this point, I should pull the rabbit-shaped solution out of a top hat. Except that I don't have one. Amalgamation into ever larger umbrella bodies (South Leicestershire Natural History Society ... Leicestershire and Rutland Natural History Society ... East Midlands Natural History Society ...) cannot replace the involvement and engagement of local community. Virtualisation via websites, Facebook groups and Twitter accounts is a partial reprieve but not a substitute for what is being lost - we are told we are in an epidemic of loneliness. I wish I had an answer. The thing I am certain of is that the solution has to be innovative and engage a different demographic than "the way we've always done it" was able to, the Victorian/Edwardian model of monthly meetings in public halls. The solution will be divisive  but to succeed, more people have to like it than were engaged with the previous model. 

If they are not close enough to a major population centre to support their dwindling demographic, societies have two options - either abandon the concept of locality and go global (push the envelope, conduct original research, engage with national and international experts), or try to change their demographic appeal to stay local. Before there were scientific journals, business was conducted via learned correspondence between scientists. What about starting an email list or a WhatsApp group (and sticking with it over the long haul until it gains traction)? Before there were natural history societies conversations happened in coffee houses. How about about a regular date in a local Costa or Cafe Nero? Drop in Wednesdays? If people don't want to come to evening talks after a long day at work, what is it that they like about Springwatch? Organize a wildlife quiz in the local pub or nature-oriented walks? None of these may work and they all take effort, but the alternative is not palatable. 

Miskell, L. (2016) Meeting places: scientific congresses and urban identity in Victorian Britain. Routledge:
"The promotion of knowledge was a major preoccupation of the Victorian era and, beginning in 1831 with the establishment of the British Association for the Advancement of Science, a number of national bodies were founded which used annual, week-long meetings held each year in a different town or city as their main tool of knowledge dissemination. Historians have long recognised the power of 'cultural capital' in the competitive climate of the mid-Victorian years, as towns raced to equip themselves with libraries, newspapers, 'Lit. and Phil.' societies and reading rooms, but the staging of the great annual knowledge festivals of the period have not previously been considered in this context. The four national associations studied are the British Association for the Advancement of Science (BAAS), the National Association for the Promotion of Social Science (NAPSS), the Royal Archaeological Institute (RAI) and the Royal Agricultural Society of England (RASE), who held annual meetings in 62 different provincial towns and cities from 1831 to 1884. In this book it is contended that these meetings were as important as royal visits and major civic ceremonies in providing towns with an opportunity to promote their own status and identity. By deploying a wealth of primary source material, much of which has not been previously utilised by urban historians, this book offers a new and genuinely Britain-wide perspective on a period when comparison and competition with neighbouring places was a constant preoccupation of town leaders."

 

Mocydiopsis attenuata - persistence pays off

I've come across Mocydiopsis attenuata several times before. At least, I think I have, but all the previous specimens have been female.  Although there are only three UK species of Mocydiopsis they are not easy to identify, and the females really can't be safely identified to species level. And there's the problem. In amongst more than a dozen females in a recent sample I finally found a male. From then on it was easy due to the characteristic aedeagus: 

There is one previous VC55 record for Mocydiopsis attenuata in the ORCA database, but it's a bit tenuous  with a range of dates and only a four figure grid reference. Without being able to see the original material I have no idea how reliable it is (verification level "Presumed Correct"), but given my previous experience... So how rare is Mocydiopsis attenuata? Well the females are not uncommon - but that's the problem. The males are rare as hen's teeth.

 

Orius vicinus (?)

A vacuum sample from streamside vegetation turned up this 2mm Anthocorid bug.

Based on the long hairs, fine punctures and transverse wrinkling on the posterior lobe of the pronotum (rather than the coarse punctures described for O. minutus), I'm pretty confident that this is Orius vicinus. However, this is a very difficult genus. This specimen shows the leg pigmentation usually described for O. vicinus, but this character is variable and not reliable (Orius (Heterorius) vicinus (Ribaut) (Hemiptera: Heteroptera: Anthocoridae) in western North America, a correction of the past. (2010) Proceedings of the Entomological Society of Washington, 112(1), 69-80). The bad news is that this specimen is a female (males do not overwinter) and my hopeful attempts to examine the bursa and copulatory tube were unsuccessful. We currently have no confirmed VC55 records for O. vicinus. 

 

Microplastics - Into the Unknown

Plastics comprise a wide range of synthetic or semi-synthetic organic compounds, typically high molecular weight polymers. While there is no universal definition of the term microplastics, here I consider them to be fragments of plastic less than 1mm in size. There are two main classes of microplastics. Primary microplastics are any plastic fragments or particles already 1mm in size or less before entering the environment, including microfibers from clothing, microbeads, and plastic pellets known as nurdles. Secondary microplastics are microplastic particles created from the degradation of larger plastic products through natural weathering processes once they enter the environment. 

So why bother looking at microplastics? Although there is now a growing literature on microplastics in aquatic environments, less is known about terrestrial ecosystems (Rillig, M. & Lehmann, A. (2020) Microplastic in terrestrial ecosystems. Science, 368 (6498), 1430-1431), and specifically the effects of microplastics on soil mesofauna, even though there is evidence that they may negatively affect soil fauna (Lin, D. et al. (2020) Microplastics negatively affect soil fauna but stimulate microbial activity: insights from a field-based microplastic addition experiment. Proceedings of the Royal Society B, 287, 1934, 20201268). 

A few months ago a came across a paper with a simplified methodology for examining microplastic contamination in biological specimens (Labbe et al (2020) Inexpensive Adaptations of Basic Microscopes for the Identification of Microplastic Contamination. J. Chem. Educ. 97, 11, 4026–4032). This paper uses Nile Red to visualise microplastic particles, a lipophilic stain most frequently used to localize and quantitate lipids, particularly lipid droplets within cells (Greenspan P, et al. (1985) Nile red: a selective fluorescent stain for intracellular lipid droplets. The Journal of Cell Biology 100 (3), 965-973). Polar lipids (i.e. phospholipids) which are mostly present in membranes, are stained in red whereas neutral lipids (cholesterol and triglycerides), present in lipid droplets, are stained in yellow. Nile Red is almost nonfluorescent in water and other polar solvents but undergoes fluorescence enhancement and large absorption and emission blue shifts in nonpolar environments (excitation/emission maxima ~552/636nm in methanol). In the paper, a 1mg/ml solution of Nile Red in methanol is used to stain the particles. After staining fluorescence is visualised by illumination of the material with a blue light source and a yellow emission filter. As in the paper, I investigated using a blue laser to get maximum fluorescence but abandoned this in favour of a blue LED flashlight for safety reasons.

Helpfully, in the European Union most plastics intended to be recycled are labelled with a numbered code:

1 - PET (Polyethylene Terephthalate)
2 - HDPE (High Density Polyethylene)
3 - PVC (Polyvinyl Chloride)
4 - LDPE (Low-Density Polyethylene)
5 - PP (Polypropylene)
6 - PS (Polystyrene)
7 - Other Non Recyclable Plastic

With everything in place, I began by testing on some known (from the recycling codes) plastics. Hydrophobic plastics such as polyethylene show yellow-green emission in the presence of Nile Red, while more hydrophilic plastics show red emission. Native cellulose fails to fluoresce but appears blue due to breakthrough of scattered light. A fragment of clear plastic food packaging labelled 1: R-PET (Recycled polyethylene terephthalate) showed only faint red fluorescence on some of the abraded surfaces:

A piece of white food packaging labelled 7: Other Non Recyclable Plastic - gave a brighter yellow emission, again mostly from abraded surfaces:

Having satisfied myself that the system was working I moved on to look at some biological materials, starting with alcohol-preserved springtails. Orchesella cincta gave a diffuse surface pattern of red fluorescence (bear in mind that these specimens are only illuminated with blue light, any other colours are due to fluorescent emissions passing through the yellow emission filter):

Dicyrtomina saundersi also gave a faint pattern of surface fluorescence, although the claws showed strong red fluorescence:

I then cleared some specimens of these two species with 10% NaOH and stained them after clearing. Very little fluorescence was visible in the D. saundersi but the O. cincta showed a bright pattern of surface fluorescence:

In none of the six specimens I examined did I detect any microplastic particles. However, these samples came from a relatively pristine environment (PAWS - planted ancient woodland sites), or at least, as pristine as it is possible to get in Leicestershire. Next I plan to look at samples from more urban environments where incidence of microplastic contamination is likely to be higher. 

  

Are spiders intelligent?

In this fascinating paper, "intelligence" is defined as flexible problem-solving capacity. So are spiders intelligent? The answer is ... sort of. The conclusion reached is that Portia, a genus of jumping spider that feeds on other spiders, is "distinctly cognitive" (able to acquire knowledge and understanding through thought, experience and the senses). That's one step short of a Gregorian creature such as a human (self-consciousness), but not bad for a spider brain.

Arthropod Intelligence? The Case for Portia (2020) 11: 568049. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591756/

Abstract:
Macphail's "null hypothesis," that there are no differences in intelligence, qualitative, or quantitative, between non-human vertebrates has been controversial. This controversy can be useful if it encourages interest in acquiring a detailed understanding of how non-human animals express flexible problem-solving capacity ("intelligence"), but limiting the discussion to vertebrates is too arbitrary. As an example, we focus here on Portia, a spider with an especially intricate predatory strategy and a preference for other spiders as prey. We review research on pre-planned detours, expectancy violation, and a capacity to solve confinement problems where, in each of these three contexts, there is experimental evidence of innate cognitive capacities and reliance on internal representation. These cognitive capacities are related to, but not identical to, intelligence. When discussing intelligence, as when discussing cognition, it is more useful to envisage a continuum instead of something that is simply present or not; in other words, a continuum pertaining to flexible problem-solving capacity for "intelligence" and a continuum pertaining to reliance on internal representation for "cognition." When envisaging a continuum pertaining to intelligence, Daniel Dennett's notion of four Creatures (Darwinian, Skinnerian, Popperian, and Gregorian) is of interest, with the distinction between Skinnerian and Popperian Creatures being especially relevant when considering Portia. When we consider these distinctions, a case can be made for Portia being a Popperian Creature. Like Skinnerian Creatures, Popperian Creatures express flexible problem solving capacity, but the manner in which this capacity is expressed by Popperian Creatures is more distinctively cognitive.

 

I've been looking for this spider for two years

The WSC describes Zygiella atrica as "common on the coast, rare in the mountains". We don't have coast or mountains in VC55 but there are around 100 well-distributed records for this species in the County database, so I wouldn't call it rare. In spite of that, it has managed to become a bogey species for me over the last two years. So much so that I was starting to doubt that I could identify this species correctly, that I was missing specimens as Zygiella x-notata. Tylan Berry didn't help by showing that Z. atrica grades into Z. x-notata morphologically, increasing my paranoia. Yesterday, on a pre-lockdown field trip, I was pretending a Gorse bush was Matt Hancock and giving it a damn good thrashing. As soon as this beauty hit the tray I knew immediately my wait was over. They do exist!

 

Ants Can't Jump

Morphological ant mimicry by Myrmarachne [ant mimic]  jumping spiders confers strong protective benefits against predators [considered to be a good example of Batesian mimicry].

BUT: 

The ant-like appearance of Myrmarachne spiders, such as narrow and constricted body with an elongated pedicel, seems unsuitable for generating the high hemolymph pressure required for jumping. 

 

Constraints on the jumping and prey-capture abilities of ant-mimicking spiders (Salticidae, Salticinae, Myrmarachne). Sci Rep 10, 18279 (2020)
https://doi.org/10.1038/s41598-020-75010-y

 

25:20 / 1:10:30 UK Spider Identification in the Field

Excellent online talk by Rich Burkmar.

Tenuiphantes Top Tips

I've spent the day working though an enormous pile of Tenuiphantes tenuis. They're not only the most common spider in VC55, they're also a right pain to separate. Which is were two top tips come in.

Top Tip No. 1: Tenuiphantes or Bathyphantes?
Easy - Tenuiphantes have a proximal dorsal spine on metatarsus I, Bathyphantes don't.

Top Tip No. 2: Which Tenuiphantes species?
These are both Tenuiphantes tenuis:

With males, the palps are confusingly similar too - until you know to check the paracymbium:

No more confusion. Thanks to Tylan Berry. 

 

Florodelphax leptosoma - a new planthopper for VC55

I recently picked up a useful field tip. If you're like me, there are certain species which you know well but can never remember the names of. The trick is to give them a name you can remember, then look them up when you get home. Among the hoppers (Auchenorrhyncha), the Planthoppers (family Delphacidae) are easy to assign to a family (large, apical movable spur on the hind tibiae), but mostly tricky to identify to species level. One exception is Conomelus anceps, which I find at almost every site I visit - but can never remember the name of:

I have been able to resolve this difficult by christening them "Minions". Problem solved. 

On a recent trip to New Lount, a few small dark Minions stood out from the crowd in the tray. On examination, these turned out to be Florodelphax leptosoma:

This is a fairly common species found in a wide range of wetland habitats across the UK, but the fact that it has never been recorded previously in VC55 points to how seriously under-recorded the Auchenorrhyncha are as a group. 

 

2020 sucks - one man and his leaf blower

Cann, AJ (2020) 2020 sucks - one man and his leaf blower. Leicestershire Entomological Society Newsletter 63: p14-15.

Image Problem

If you think spiders have an image problem, try working on ticks...

Why would anyone want to work on ticks?
A friend who rescues hedgehogs asked me to look at some ticks. Sickly rescue hedgehogs seem to be particularly prone to tick infestation. I had a bad experience with ticks a couple of years ago, but so far, I've never been bitten and with the prevalence of Lyme Disease now, I am very careful when I'm out. In fact, compared with mites which are everywhere (and which I feel a little bit guilty about not working on), I never see ticks in the field, so my first thought, with rescued hedgehogs coming in from all over the County, was Oh good, a ready source of specimens. We know very little about ticks in VC55. In the middle of a zoonotic pandemic, that's really a shameful situation since apart from stupid behaviour like eating bats, we don't know where the next zoonotic pandemic is coming from - only that there will be one.

Ticks are Arachnids, so no problem - except that I'm an Araneae guy who knows very little about Acari. Obviously the place to start was with some basic research. Ticks fall into two groups, Ixodidae the hard-bodied ticks and Argasidae - soft ticks. That's nice because it eliminates half of them to start with as the specimens I had were clearly Ixodidae (internal spur on Coxa1 and genital aperture between Coxa3):



Next was time for some research on hedgehog ticks, which led me to a few interesting facts. It's commonly assumed that the ticks found on hedgehogs are Hedgehog Ticks, Ixodes hexagonus, but in fact they're equally likely to be Sheep/Deer Ticks, Ixodes ricinus. I'd been under the impression that Ixodes ricinus was the main vector for Lyme Disease, but it turns out that lots of tick species are responsible, including Hedgehog Ticks. It wasn't too hard to decide that these were Ixodes hexagonus and not I. ricinus - palps slope inwards, Tarsi1 are stepped:



There are a lot of people who would like to improve the public reaction to spiders, and wasps have had a lot of good PR recently for their role in controlling pest insects, so to rehabilitate the tick, let's compile a list of their beneficial aspects. Well there's ... umm - it's a tricky sell.

Revealing the venomous secrets of the spider's web

Golden silk orb-weaver Nephila clavipes / Charles J Sharp / CC BY-SA

Not a British spider, but this is interesting:

Revealing the venomous secrets of the spider's web. (2020) J Proteome Res. https://pubs.acs.org/doi/10.1021/acs.jproteome.0c00086

Orb-weaving spiders use a highly strong, sticky and elastic web to catch their prey. These web properties alone would be enough for the entrapment of prey; however, these spiders may be hiding venomous secrets in the web, which current research is revealing. Here, we provide strong proteotranscriptomic evidence for the presence of toxin/neurotoxin-like proteins, defensins and proteolytic enzymes on the web silk from Nephila clavipes spider. The results from quantitative-based transcriptomics and proteomic approaches showed that silk-producing glands produce an extensive repertoire of toxin/neurotoxin-like proteins, similar to those already reported in spider venoms. Meanwhile, the insect toxicity results demonstrated that these toxic components can be lethal and/or paralytic chemical weapons used for prey capture on the web; and the presence of fatty acids in the web may be responsible mechanism for open the way to the web-toxins for accessing the interior of prey's body. Comparative phylogenomic-level evolutionary analyses revealed orthologous genes among two spider groups - Araneomorphae and Mygalomorphae; and the findings showed protein sequences similar to toxins found in the taxa Scorpiones and Hymenoptera in addition to Araneae. Overall, these data represent a valuable resource to further investigate other spider web toxin systems; these data also suggest that N. clavipes web is not a passive mechanical trap for prey capture, but it exerts an active role in prey paralysis/killing using a series of neurotoxins.

 

Woodlice Change the Habitat Use of Spiders in a Different Food Chain

This is an interesting one:

Woodlice change the habitat use of spiders in a different food chain. (2020) PeerJ. 2020; 8: e9184. https://doi.org/10.7717/peerj.9184

Background: In old field systems, the common woodlouse may have an indirect effect on a nursery web spider. Woodlice and nursery web spiders feed in different food chains, yet previous work demonstrated that the presence of woodlice is correlated with higher predation success by nursery web spiders upon their grasshopper prey. This finding suggested a new hypothesis which links two seemingly disparate food chains: when woodlice are present, the spider predator or the grasshopper prey changes their location in the vegetative canopy in a way that increases their spatial overlap and therefore predation rate. However, warming temperatures may complicate this phenomenon. The spider cannot tolerate thermal stress, meaning warming temperatures may cause the spider to move downwards in the vegetative canopy or otherwise alter its response to woodlice. Therefore, we would expect warming and woodlice presence to have an interactive effect on predation rate. Results: Habitat domain observations revealed that spiders shift upward in the canopy when woodlice are present, but the corresponding effect on grasshopper prey survival was variable over the different years of study. Under warming conditions, spiders remained lower in the canopy regardless of the presence of woodlice, suggesting that thermal stress is more important than the effect of woodlice. Our modelling results suggest that spiders do not need to move away from woodlice to maximize net energy gain (expected net energy gain and signal detection theory models). Instead spider behavior is consistent with the null hypothesis that they move away from unsuccessful encounters with woodlice (individual-based simulation). We conclude that mapping how predator behavior changes across biotic (e.g. woodlouse presence) and abiotic conditions (e.g. temperature) may be critical to anticipate changes in ecosystem dynamics.

A time of change

Blogger has forced the new interface on me. I hate it and had to go back to the legacy interface to publish this because I couldn't insert an image in the new version. I'm wondering if it's time to go back to Wordpress again, but more realistically, since most of my posts are image-oriented, it's likely to be Flickr. After 24 years of Photoshop, I've moved to Affinity Photo. I'm finding it quite a learning curve. But now the important stuff. I've been a Zerene Stacker user for years but for a number of reasons felt I ought to try Helicon Focus, so I grabbed the nearest spider and took a 27 photo stack, then ran them both through Zerene (PMax) and Helicon (Method C):


Spot the difference? Actually there is one, but maybe not what you think. There are lots of reviews of Zerene versus Helicon online, and I can now confirm what they all say! Zerene is *marginally* sharper - but only if you pixel-peep, Helicon is much faster (4-5 times on my setup). What does this mean in practice? A 27 image stack that takes 3 minutes 14 seconds to process with Zerene runs in 40 seconds with Helicon. But Helicon is over a hundred quid and marginally less sharp. I may be better investing in hardware. Opinions welcome!

(Update: partial solution to the Blogger problem, a browser conflict).

In the vernacular

Hypomma bituberculatum

The old discussion about English Common Names has reared it's head again. It goes like this: Latin binomials are not memorable to the general public and off-puttingly technical to casual observers. Spiders would be more popular if they had accessible common names like flowers, birds, dragonflies and moths. Wouldn't you like to spend an afternoon in a beautiful water meadow with Swallows buzzing around your ears, head down looking for the Wrinkly-Arsed Marsh Knobhead?

Scorched Earth

The highlight of my spider year in 2019 was documenting the remarkable range expansion of Agelena labyrinthica in VC55 (Cann, A., Cann, J. (2020) 2019: A Remarkable Year For Agelena labyrinthica. https://doi.org/10.6084/m9.figshare.11918838.v1). Having been somewhat lockdown limited until recently I haven't recorded this species yet in 2020, but they are now appearing and records are being submitted. One remarkable observation caught my attention, the occurrence of the characteristic funnel webs in bare ploughed soil. I've never seen this before, but what this also makes clear is the the seemingly unstoppable march of Agelena labyrinthica continues:

Notes on Scotophaeus blackwalli

The Mouse Spider, Scotophaeus blackwalli, is a familiar inhabitant of homes and gardens, but there is a fly in the ointment. There is a second species of Scotophaeus in the UK, S. scutulatus. However, although widespread in Europe, this is very rare in the UK with only three British specimens recorded. The snag is that its close similarity to S. blackwalli means that other specimens may be overlooked. Thus, I feel morally obliged to check every Scotophaeus I see. Because Mouse Spiders are furry, it's difficult to get a good view of the epigyne without killing them, and as they are so common, that's a problem. Having been sent several Scotophaeus to I.D. today, I have been working on a better way of checking that works on live specimens.


Female Scotophaeus blackwalli

Scotophaeus blackwalli has 3 dorsal spines on femur III & IV (small juveniles may lack the diagnostic distal spine).
Scotophaeus scutulatus has 2 dorsal spines (proximal and median, no distal spine) on femur III & IV.

So telling them apart is "easy" - just look at the spines:


Male Scotophaeus blackwalli: P - proximal spine; M - median spine; D - distal spine (absent in S. scutulatus); S - scutellum (from the Latin for "shield"), an abdominal chitinous plate only present in males - is this for additional protection during mating?


I am indebted to Simeon Indzhov for his patient advice :-)

#LockdownSucksChallenge Round 4 - a couple of noobs

Pocadicnemis pumila

I've finished doing the I.D.s for round 4 (for me) of the #LockdownSucksChallenge. Most of the species are familiar from previous rounds (but a nationwide picture of abundance and phenology will be useful), but there are some changes. Ceratinella brevipes and Pocadicnemis pumila are new for me, and not frequently recorded in VC55 (possibly because of identification difficulty). In addition, my local Pardosa and Xysticus are now (mostly) mature, signalling the start of a mad scramble of the next couple of months.


Pardosa amentata

The full list from this round is:

Bathyphantes gracilis 2m 1f
Ceratinella brevipes 1m 3f
Dicymbium nigrum/brevisetosum agg 1m
Dismodicus bifrons 1f
Erigone dentipalpis 1m 2f
Erigonella hiemalis 5f
Oedothorax fuscus 1f
Pachygnatha degeeri 1m
Pardosa amentata Abundant
Pocadicnemis pumila 1f
Xysticus cristatus 2f

How to improve your microscopy

There's no doubt that microscope optics are important in forming a good image, and if you're going to record the output as a photo or a video, then the capture system and linking optics are important too.  However, I'm increasingly coming round to the view that the lighting is as important as the above.  It doesn't matter if you're using a fancy microscope and an expensive camera or a cheap microscope and holding your mobile phone to the eyepiece to take photos, if the lighting is working against you, then you're going to struggle. Like many people I've been using Ikea Jansjo LED lamps for microscopy. They're relatively cheap and they work OK, but it wasn't until I bought a Brunel Microscopes Dual Flexilite LED unit recently that my eyes were opened:



Using exactly the same optics, the quality of the images I can produce with my kit has improved 10-fold. Here's Dismodicus bifrons, a 2mm-long spider:



And here's the epigyne from this specimen, which is approximately 0.1mm:



I've never been able to produce images this good before. What has changed? Not the optics - only the lighting.

'Tis the season

One of the reasons I like Linyphiidae is because you can find mature specimens all year round. Other very common spiders are often frustrating because they have such short seasons when the are mature and can be identified. In the last week I've had, for the first time this year, mature specimens of Metellina (mengei), Pardosa (pullata), Philodromus, Tetragnatha and Xysticus. It think it's summer. In a normal year this would signal the start of a mad couple of months of recording, before they all go away in the autumn and it's back to Linyphiids for the winter. This year ... who knows?

#LockdownSucksChallenge Round 3 - is that a scapus in your pocket or are you just pleased to see me?

I've just finished checking the I.D.s for #LockdownSucksChallenge Round 3. Mostly this was a repeat of earlier finds, but with the addition of one new species, an old friend:



Bathyphantes gracilis 1m 1f
Dicymbium nigrum/brevisetosum agg 4f
*Diplostyla concolor 1f
Erigone dentipalpis 5m 3f
Erigonella hiemalis 3m 6f
Pachygnatha degeeri 1m

Farewell old friend?

Last year when I was considering which spider species to use a a benchmark for spider recording, I was surprised that the familiar (and easily identified) Garden Spider, Araneus diadematus, was not the best choice (see: Benchmarking Spider Recording, and: Spider Recording in Leicestershire and Rutland). Instead, the money spider Tenuiphantes tenuis was the best fit. While this may be a quirk of the data, it seems that like the familiar House Sparrow, our old friend the facefull-of-spiderweb Araneus diadematus could be on the way out:

"The drastic decline in the abundance of the orb-weaving spider Araneus diadematus over the past half-century documented in this study (Table 1) apparently reveals a bottom-up trophic cascade in response to the widespread insect losses that have occurred across large parts of Europe in recent decades."



Where Have All the Spiders Gone? Observations of a Dramatic Population Density Decline in the Once Very Abundant Garden Spider, Araneus diadematus (Araneae: Araneidae), in the Swiss Midland. https://www.mdpi.com/2075-4450/11/4/248/htm
Aerial web-spinning spiders (including large orb-weavers), as a group, depend almost entirely on flying insects as a food source. The recent widespread loss of flying insects across large parts of western Europe, in terms of both diversity and biomass, can therefore be anticipated to have a drastic negative impact on the survival and abundance of this type of spider. To test the putative importance of such a hitherto neglected trophic cascade, a survey of population densities of the European garden spider Araneus diadematus—a large orb-weaving species—was conducted in the late summer of 2019 at twenty sites in the Swiss midland. The data from this survey were compared with published population densities for this species from the previous century. The study verified the above-mentioned hypothesis that this spider’s present-day overall mean population density has declined alarmingly to densities much lower than can be expected from normal population fluctuations (0.7% of the historical values). Review of other available records suggested that this pattern is widespread and not restricted to this region. In conclusion, the decline of this once so abundant spider in the Swiss midland is evidently revealing a bottom-up trophic cascade in response to the widespread loss of flying insect prey in recent decades.

Upping my game

My standard setup for most microscopy is a stereomicroscope and an LED ring light (switching to a compound microscope if I need to). Stereomicroscopes tend to be optimized for depth of field rather than resolution. Ring lights tend to produce flat images with minimal shadows because the light is directly above the specimen. Put the two together and the images tend to be low contrast and muddy. Adding adjustable low incident angle spot lighting produces controllable shadows and therefore adds to the 3D effect of the image. I'm a big fan of the 10W Ikea Jansjö LED worklamps for supplemental lighting - they're cheap and convenient but they do have a few issues. They are a warm colour (somewhere around 3000 K) and since my ring light is more of a daylight spectrum (around 5000 K), it's difficult to produce images with accurate colour. Second, they have quite a wide angle of incidence and thus tend to produce quite a lot of scatter.

Today I took delivery of a Brunel Microscopes Dual Flexilite LED unit - big shoutout to Brunel, it arrived 48 hours after ordering. It's well made and for a piece of microscope kit, reasonably priced. More importantly, it's bloody good. Using the carefully angled incident light from this unit to supplement the LED ring light (same colour), the resolution is much better than the ring light alone and considerably better than using the Jansjö LED lamps. Sadly, the specimens I pulled out of the freezer to try it out on were both immature, but I'm very happy with the quality of the images.



A juvenile Metellina, which I strongly suspect is M. merianae, but I can't prove it:




(Click for larger images)

Gonatium rubens? Gongylidium rufipes? Hypomma bituberculatum? We'll never know! Don't worry about it and just admire the quality of the image!

(Click for larger image)

Leicestershire LadyBirds A-Poppin

Nephus quadrimaculatus

Over the last couple of weeks the Leicestershire ladybird scene has gone a bit mad (see: NatureSpot Lockdown Challenge - Operation Ladybird). Trying not to be left out, on my daily exercise yesterday I gave the local Ivy a damn good thrashing, and was rewarded with my target species, Nephus quadrimaculatus. The first VC55 record for this species was only a couple of weeks ago, but now they're popping up all over the County, which only goes to show ... seek and ye shall find?

Today I will be mostly processing all the spiders :-)


Rhyzobius chrysomeloides

#LockdownSucksChallenge - Round 2 Results

Following the first round a couple of weeks ago I've finally finished processing the samples from Round 2 (for me) of the #LockdownSucksChallenge. For various reasons, it's taken a week. Scores on the doors:

Bathyphantes gracilis 2f
Dicymbium nigrum/brevisetosum agg 3m 3f
Dicymbium nigrum sensu stricto 1m
Diplocephalus latifrons 1m
Erigone dentipalpis 1m
Erigonella hiemalis 2m 6f
Micrargus herbigradus 1m 2f
Tenuiphantes tenuis 1f
Tenuiphantes zimmermanni 1m
Ozyptila praticola 1i

No analysis at present, just records. Thinking to come later ;-)

Wild and Wacky (We are the Robots)

When I talked about spider recording in VC55 a couple of months ago, the discussion quickly became "imaginative", and by the end of the meeting, we had "decided" ;-) to equip a drone with an eVac and program it to fly a 10m grid covering the whole of VC55 taking samples. These would need to be sorted by hand to sort out the [insert taxon of choice, e.g. spiders] from the debris, and then sent off for DNA barcoding (High-throughput sequencing for community analysis: the promise of DNA barcoding to uncover diversity, relatedness, abundances and interactions in spider communities (2020) Development Genes and Evolution volume 230, 185–201). Not good news if you're an ecological consultant, great news for gene jockeys.

Mass sampling projects are "easy" to set up. "Hey, I know, let's sequence the whole of Wytham Woods." There was another one published yesterday (Changes in phenology and abundance of suction‐trapped Diptera from a farmland site in the UK over four decades. (2020) Ecol Entomol). What's not easy is processing the data they produce. It took the Danes 15 years to record the results of their malaise traps (The Swedish Malaise Trap Project: A 15 Year Retrospective on a Countrywide Insect Inventory (2020) Biodiversity Data Journal 8: e47255). Right now DNA barcoding is the only feasible way of tackling the mass of data such projects produce. But maybe not for much longer. A.I. (Artificial Intelligence) is coming: A light trap and computer vision system to detect and classify live moths (Lepidoptera) using tracking and deep learning. (2020) bioRxiv https://doi.org/10.1101/2020.03.18.996447, and: Successful launch of automatic insect counting in North Holland. I've been concerned about the impact of A.I. for some time. Well, not about A.I. as such, more about A.S. - the poorly functioning first generation systems - Artificial Stupidity. It's not there yet, but inevitably it will come.

Recently I've noticed a disturbing trend in entomology blog posts to include dodgy music videos. Until the A.I. finally takes over, it seems that We are the Robots:

#LockdownSucksChallenge - The Results

A few days ago Richard Wilson came up with the idea that arachnologists with vacuum samplers might like to vacuum their garden lawns for two minutes and compare results on the spiders they found. I did, and found:

Bathyphantes gracilis 1f
Diplocephalus latifrons 7m 1f
Erigone dentipalpis 5f
Erigonella hiemalis 4f
Microneta viaria 2f
Tenuiphantes tenuis 2f
Xysticus cristatus 1f

Not too bad for 2 minutes. The data will be collated and thus contribute to a larger study of garden faunas.

Spider Recording in Leicestershire & Rutland

This is a shortened version of a talk I gave recently at the Leicestershire Entomological Society. Enjoy!

The Moths Arrive

Much eVaccing in the Marsh

Given a few brief hours sunshine this week, I headed out for only the second time this month (shocking!). Where do you go when you've had over three times the average February rainfall? Well obviously the choice was between the local bog and the local marsh. I decided to play it safe and head for the marsh! In fact, it was surprisingly dry, which is worrying in it's own right considering the rest of the County is under water. This is one of only a few sites with reed beds but it won't be there much longer if it continues drying at this rate. This was the first opportunity to poke around a reed bed with the eVac and it produced some goodies. The first of these was the bug Chartoscirta cincta:



Not a rare species but there are few records for VC55 and it's the first time I've recorded it. The second specimen of note was a juvenile Episinus angulatus, also comparatively rare on the County.



I've always thought you can't beat a good marsh. Unless it's a bog.

Colonized

Psilochorus simoni

In December I found a single Psilochorus simoni in my kitchen. This could have been an isolated incomer, but this morning I found two adult females. Clearly I have my own little colony (dollar signs, how much can I sell them for? ;-)

Two observations. First, the adult females are tiny compared with Pholcus phalangioides. Second, I seem to have seen fewer Pholcus around recently... This morning specimens were sharing a corner with a juvenile Steatoda grossa - I suspect this comparatively small species packs a punch and is well capable of looking after itself.

The Pink Prowler

After two weeks of illness, storms, February rainfall now approaching three times the monthly average figure and days and days of endless R, I was determined to get out and do some fieldwork today. Determined. Those 40mph winds weren't going to stop me! When I woke the sun was shining and I sprang out of bed to charge the eVac battery. Dressed, breakfast ... then it rained, hard and horizontally. It's only a shower! It's all clear behind, I'll give it half an hour then head out. After half an hour, it rained again. And again. After two hours I gave up and went to get changed. As I walked into the bathroom I saw a tiny orange spider on the wall. Although I've never seen Oonops before, from the cluster of eyes and the way it ran, stopped, and ran again, I knew what it was.



However, I didn't know which of the two UK species it was. Under the microscope I could count 5 ventral spines on tibia I, meaning this was Oonops domesticus, which the BAS web page calls the "Pink Prowler" (c.f. Oonops pulcher, 4 spines on tibia I):



This 1.5-2mm, pinkish-orange spider has a highly characteristic way of slowly walking with its front legs out-stretched, interspersed with short bursts of running. Its small size and pinkish colour make it difficult to spot, particularly because it often nocturnal. During the day, it hides away in a silken cell behind furniture, curtains, pictures, papers, etc. In warmer parts of Europe this spider lives under stones, amongst leaf-litter, etc. In the UK it is more or less completely synanthropic and only found in houses, feeding on tiny prey such as mites and booklice. There are relatively few records, but this species is under-recorded due to its small size and nocturnal habits. There's a fair chance you have it in your house. Go look while it's raining.