The end of an era...

Well done guys but - "The field campaign involved the deployment of 73 Malaise traps at 55 localities across the country for three years (2003-2006). Over the past 15 years, the collected material has been hand sorted by trained technicians into over 300 taxonomic fractions suitable for expert attention."

It took 15 years to process the data. In 15 years time, how many trained entomologists capable of doing this will we have? Will citizen scientists step up? Undaunted by this problem - they're now running a project with 200 Malaise traps! (Insect Biome Atlas, https://www.insectbiomeatlas.com) Of course, the new project is a barcoding survey ...


The Swedish Malaise Trap Project: A 15 Year Retrospective on a Countrywide Insect Inventory (2020) Biodiversity Data Journal 8: e47255 https://bdj.pensoft.net/article/47255/list/8/
The Swedish Malaise Trap Project (SMTP) is one of the most ambitious insect inventories ever attempted. The project was designed to target poorly known insect groups across a diverse range of habitats in Sweden. The field campaign involved the deployment of 73 Malaise traps at 55 localities across the country for three years (2003-2006). Over the past 15 years, the collected material has been hand sorted by trained technicians into over 300 taxonomic fractions suitable for expert attention. The resulting collection is a tremendous asset for entomologists around the world, especially as we now face a desperate need for baseline data to evaluate phenomena like insect decline and climate change. Here, we describe the history, organisation, methodology and logistics of the SMTP, focusing on the rationale for the decisions taken and the lessons learned along the way. The SMTP represents one of the early instances of community science applied to large-scale inventory work, with a heavy reliance on volunteers in both the field and the laboratory. We give estimates of both staff effort and volunteer effort involved. The project has been funded by the Swedish Taxonomy Initiative; in total, the inventory has cost less than 30 million SEK (approximately 3.1 million USD). Based on a subset of the samples, we characterise the size and taxonomic composition of the SMTP material. Several different extrapolation methods suggest that the material comprises around 20 million specimens in total. The material is dominated by Diptera (75% of the specimens) and Hymenoptera (15% of specimens). Amongst the Diptera, the dominant groups are Chironomidae (37% of specimens), Sciaridae (15%), Phoridae (13%), Cecidomyiidae (9.5%) and Mycetophilidae (9.4%). Within Hymenoptera, the major groups are Ichneumonidae (44% of specimens), Diaprioidea (19%), Braconidae (9.6%), Platygastroidea (8.5%) and Chalcidoidea (7.9%). The taxonomic composition varies with latitude and season. Several Diptera and Hymenoptera groups are more common in non-summer samples (collected from September to April) and in the North, while others show the opposite pattern. About 1% of the total material has been processed and identified by experts so far. This material represents over 4,000 species. One third of these had not been recorded from Sweden before and almost 700 of them are new to science. These results reveal the large amounts of taxonomic work still needed on Palaearctic insect faunas. Based on the SMTP experiences, we discuss aspects of planning and conducting future large-scale insect inventory projects using mainly traditional approaches in relation to more recent approaches that rely on molecular techniques.

The Micraria Mess

Micaria pulicaria is a common ant-mimic spider and fairly easy to recognize, although there are rarer similar species. At least, that was true until a new paper which was published (see below). In a nutshell, the authors performed DNA analysis of putative Micaria pulicaria specimens and found that they are a mix of cryptic species. We've been here before - Pardosa lugubris is now P. saltans, although in this case renaming was due to the fact that via behavioural observations researchers recognised that there were two distinct mating dances in the two species and then followed this up with morphological analysis which revealed some (subtle) physical differences. The new paper is DNA-led with morphological confirmation, but at this point it gets embarrassing. In the jargon, the cryptic species are known as "OTUs" (Operational Taxonomic units) - i.e. groupings with more similarities than differences. However, the morphological differences aren't exactly subtle:

OTU1 (= Micaria micans) has a dark longitudinal stripes on the dorsal of femora III and IV (sometimes also recognizable on the tibiae of these legs), caused by stripe-like arrangement of dark hairs and dark pigmentation of the cuticule (see the photo above).
OTU2&3 (= Micaria pulicaria) does not have the go-faster stripes.

You might have thought that this would have been easy to spot, but apparently not! Even more embarrassing was the fact that the species we know in the UK as Micaria pulicaria was originally named as Micaria micans, but this seems to have been lost along the way.


https://doi. org/10.1111/zsc.12404

It turns out that the true M. pulicaria appears to be confined to inaccessible northern or montane regions or otherwise specific locations. All day long UK arachnologists have been scrambling to look at their specimens and photographs, and it turns out most UK specimens are striped, hence Micaria micans rather than pulicaria.

We'd better get used to this - DNA is going to keep tripping us up for decades to come.

Read:

Muster C, Michalik P. (2019) Cryptic diversity in ant-mimic Micaria spiders (Araneae, Gnaphosidae) and a tribute to early naturalists. Zool Scr. 00: 1–13. https://onlinelibrary.wiley.com/doi/10.1111/zsc.12404
"Spiders of the genus Micaria are ground-living mimics of ants. Species delineation in these spiders is challenging, mainly because of exceptional high levels of intraspecific variation masking species boundaries. As implied by preliminary DNA barcode data from Central Europe, the Holarctic and very widely distributed glossy ant-spider M. pulicaria shows cryptic diversity. Here, we disentangle the hidden diversity by means of an integrative taxonomy approach, using mitochondrial DNA, morphometrics, traditional genitalic characters and ecology. Our data suggest the clear delineation of two distinct species, which supports the conception of 19th century taxonomists. These early naturalists distinguished M. pulicaria and a second closely related species based on morphology and natural history, which were synonymized in subsequent taxonomic studies. Therefore, we re-circumscribe M. pulicaria and revalidate the long forgotten M. micans. These two Micaria species co-occur sympatrically in vast areas of the western Palearctic, while the Nearctic region is populated by M. pulicaria alone. Male genitalic traits are more dissimilar in the area of sympatry than in allopatry, suggesting a decisive role of reproductive character displacement in species diversification. Our study emphasizes the value of the early taxonomic literature in integrative taxonomic studies, as it may contain crucial information on natural history that are not regularly recorded by modern taxonomists."


Update: Helpful advice from Richard Gallon, Cofnod:

• Micaria pulicaria sensu lato: all old records into until the specimens have been redetermined.
• Micaria pulicaria sensu stricto: records where the specimen has been redetermined in light of the new paper.
• Micaria micans: records where the specimen has been redetermined in light of the new paper.

It seems that specimens from warm dry sites (thermophilic) are Micaria micans. Genuine Micaria pulicaria s.s. appear to favour damper habitats. If the specimen has black dorsal stripes on femurs III & IV and is from a dry habitat then it is Micaria micans. If it lacks these dorsal stipes on femurs III & IV (particularly if it’s from a damp habitat), then it’s Micaria pulicaria sensu stricto (although be careful you are not dealing with old faded material). If you aren’t sure put it down as M. pulicaria sensu lato.

There are also characteristics on the epigyne and particularly the palp which help, but they are subtle! The colouration difference is a reliable and supported by DNA. It will take some time to work out the distribution of both species but the paper confirms that both species are present from the UK, including Wales and Scotland.

Update2 February 2020:
On 12.02.2020 the World Spider Catalogue formally recognised the split of M. pulicaria and M. micans. This change will be included in the next UK checklist in about 5 years time.
Danniella Sherwood (NHM) and Richard Gallon (World Museum Liverpool) have checked museum specimens and found the leg stripe character of UK specimens is consistent with the genital morphology of the corresponding taxa. Difficulty may arise with very faded specimens (e.g. historical) and immatures.

Verification Required

There's a telling sentence in a recently published paper:

"The finding is strongly suggestive of a changing role of recording schemes, with a movement away from simply harvesting and collating data from known recorders, towards a more inclusive teaching and mentoring role."



Evaluating the ability of citizen scientists to identify bumblebee (Bombus) species. PLoS ONE 14(6): e0218614 (2019). https://doi.org/10.1371/journal.pone.0218614
Citizen science is an increasingly popular way of engaging volunteers in the collection of scientific data. Despite this, data quality remains a concern and there is little published evidence about the accuracy of records generated by citizen scientists. Here we compare data generated by two British citizen science projects, Blooms for Bees and BeeWatch, to determine the ability of volunteer recorders to identify bumblebee (Bombus) species. We assessed recorders’ identification ability in two ways–as recorder accuracy (the proportion of expert-verified records correctly identified by recorders) and recorder success (the proportion of recorder-submitted identifications confirmed correct by verifiers). Recorder identification ability was low (<50% accuracy; <60% success), despite access to project specific bumblebee identification materials. Identification ability varied significantly depending on bumblebee species, with recorders most able to correctly identify species with distinct appearances. Blooms for Bees recorders (largely recruited from the gardening community) were markedly less able to identify bumblebees than BeeWatch recorders (largely individuals with a more specific interest in bumblebees). Within both projects, recorders demonstrated an improvement in identification ability over time. Here we demonstrate and quantify the essential role of expert verification within citizen science projects, and highlight where resources could be strengthened to improve recorder ability.

Unearthing the "lost" spiders of Leicestershire

Cann, A.J. (2020) Unearthing the "lost" spiders of Leicestershire. Leicestershire Entomological Society Newsletter 62: p1, 2-4.

Click for larger images:

While Waiting for the Wasp Spider

Argiope bruennichi is very much on my radar, with known colonies only a few miles from the VC55 border - I'm keeping my eyes open. Accordingly I was interested in this mew paper, which suggests that the dramatic range expansion in this species is due to environment (climate) and not to any change in the spiders themselves.


Dispersal and life-history traits in a spider with rapid range expansion. Mov Ecol 8, 2 (2020)
https://movementecologyjournal.biomedcentral.com/articles/10.1186/s40462-019-0182-4
Dispersal and reproduction are key life-history traits that jointly determine species’ potential to expand their distribution, for instance in light of ongoing climate change. These life-history traits are known to be under selection by changing local environmental conditions, but they may also evolve by spatial sorting. While local natural selection and spatial sorting are mainly studied in model organisms, we do not know the degree to which these processes are relevant in the wild, despite their importance to a comprehensive understanding of species’ resistance and tolerance to climate change. The wasp spider Argiope bruennichi has undergone a natural range expansion - from the Mediterranean to Northern Europe during the recent decades. Using reciprocal common garden experiments in the laboratory, we studied differences in crucial traits between replicated core (Southern France) and edge (Baltic States) populations. We tested theoretical predictions of enhanced dispersal (ballooning behaviour) and reproductive performance (fecundity and winter survival) at the expansion front due to spatial sorting and local environmental conditions. Dispersal rates were not consistently higher at the northern expansion front, but were impacted by the overwintering climatic conditions experienced, such that dispersal was higher when spiderlings had experienced winter conditions as occur in their region. Hatching success and winter survival were lower at the range border. In agreement with theoretical predictions, spiders from the northern leading edge invested more in reproduction for their given body size. We found no evidence for spatial sorting leading to higher dispersal in northern range edge populations of A. bruennichi. However, reproductive investment and overwintering survival between core and edge populations differed. These life-history traits that directly affect species’ expansion rates seem to have diverged during the recent range expansion of A. bruennichi. We discuss the observed changes with respect to the species’ natural history and the ecological drivers associated with range expansion to northern latitudes.

Exciting Times for Spiders in Leicestershire and Rutland

Cann AJ (2020) Exciting Times for Spiders in Leicestershire and Rutland. Leicestershire and Rutland Wildlife Trust Wild Magazine, Winter 2020.

Click for larger image:

You Slag!

I don't watch Eastenders, but turning over lumps of slag looking for invertebrates on an abandoned post-industrial site recently started me musing on post-industrial conservation.

When I talked about the spiders of Leicestershire and Rutland at the Leicester Literary and Philosophical Society recently I found myself slipping into a familiar rant about the management of "nature" reserves and the deathly grip of "wildflower meadows" on all other taxa. Close mowing in August is "good for the flowers" and the only thought given to insects stops with the limited concept of "pollinators" - by which they mean "bees". No thought is given to the damage done to other taxa by close mowing. We've all seen examples of this on road verges and other sites. Yet these sites have to be managed and in most instances, grazing is not an available option. The best compromise would be only to mow part of the reserve on an annual rotation, with the rest being left alone. At the end of my talk a friend popped up and told me to go to Asfordby Hill (where the slag comes from) - so I did.

In 1985 I was living in California and only dimly aware of the final stages of the miner's strike playing out. It was only a decade later visiting ex-mining communities when the enormity of the societal change dawned on me. In January 2020 I sit here fretting about the next big one, the post-CAP agricultural future. Asfordby Colliery was the last deep coal mine sunk in England and at it's peak employed nearly 500 people. After investing close to half a billion pounds, the mine closed in 1997. On a rare sunny day in January, Asfordby Hill looks almost lovely, with huge swathes of Cladonia rangiformis glistening between the nursery forest of self-seeded Birch. I haven't had chance to complete my entomological analysis yet, but even in January it's looking like an exceptional site. In the denuded Watsonian vice county of VC55 all our finest conservation sites are post-industrial - Bloody Oaks, Ketton, Holwell, Eyebrook. Bagworth Heath was my (belated) discovery of 2019, and has been a delight - Marbled Whites, Sand Martins and Heather. Trudging across the biodiversity agrideserts that industrial farming has wrought on Leicestershire makes me wonder about the coming era of post-subsidy, post-industrial farming. It's not clear to me where rewilding is going in the lowlands and to me the post-agricultural future looks a lot more like solar farms and yoga yurts than packs of wolves sweeping majestically across the plains of Leicestershire. Rewilding Leicestershire looks a lot more like birches and lichens than bison and brown bears.