Validating records that are not supported by a voucher

I am currently working my way through iRecord data for 2017. Some of it is relatively straightforward, especially where I know the recorder and his/her abilities and techniques. But, what do you do with records from somebody you don't know who has submitted a record that might be plausible but you know could easily be wrong?

Several records gave me this conundrum today. I had the usual problem with Syrphus ribesii being used for all yellow and black striped Syrphus. For these, unless there is a photo that I can work from, I mark all with a query because I've seen so many unidentifiable photographs posted as this species. I do accept records by people I know and whose techniques I am familiar with.

The bigger problems come in the case of relatively easily identified species at the wrong time of year. Two examples emerged today: three records of Volucella bomylans in August and one of Merodon equestris in late July. The problem is that they were the majority of records seen for these species in today's session and they don't tally with the normal phenology plots for either species. Fortunately, we have a way of telling whether they are well within or on the limits of believability.

This is where extracting records direct from Facebook helps. I have access to a detailed dataset for both species in 2017 all of which I have checked from photographs. In the case of V. bombylans there are 202 records and for M. equestris there are 353 records. In neither case is there much evidence of large numbers at the times of year of the questionable records, as can be seen from the accompanying graphs.

So, do I mark as plausible, or should I reject the records? What would you do?

Figure 1. Phenology of Volucella bombylans in 2017.

Figure 2. Phenology of Merodon equestris in 2017

Why the decline in insect biomass (and diversity)?

The work of the Krefeld Entomological Society surfaced again this week in post on the UK Hoverflies Facebook page, raising the big question ‘why such a decline’? In the absence of fully correlated data it is very difficult to draw any firm conclusions but I suspect we are looking at some form of ‘death by a thousand cuts’.

A lot of blame must lie with post-war agricultural intensification: increased use of pesticides, deep ploughing, amalgamation of fields and the loss of a huge acreage of hedgerows and associated habitat. But, the decline has been ongoing, whilst many of the (seemingly) most damaging actions took place before the Krefeld sampling programme first started. So, although DDT took a terrible toll on insect life, it is not the only culprit. There have been subsequent generations of insecticides, all of which must have some impact, if not quite so serious. Maybe Neonectinoids are to blame for post 1980s crashes? They will have had some impact and it is possible that they will still be found to have had a bigger impact than is currently believed?

I suspect that we are actually looking at a series of hammer blows. Post-war intensification must already have had a massive impact by the time I started to take an interest in insects; yet in my childhood I could still find, with relative ease, the larvae of puss moth, poplar and lime hawkmoth, and a plethora of other lovely animals. Now I cannot, even though I still visit the same place and look on many of the same trees! My garden moth trap is no longer invaded by clouds of garden tiger moths and I cannot recall when I last found its caterpillar in south London!

My local ‘patch’ comprises several square kilometres of open habitat enclosed by urban sprawl. I guess it has become somewhat more isolated over time but, even so, it has not been affected by herbicides and pesticides. It has, however, been affected by increased nitrification and the vegetation seems to me to have lost some of its low-nutrient characteristics, even though most of the characteristic plants still survive. At the same time, we are told that air quality has improved, and so it has if the range of lichens now growing on our roof are a reasonable indicator. We no longer have vast quantities of atmospheric lead from car exhausts, but do we have higher volumes of pm10s.

More recent events

In my lifetime I have witnessed several ‘events’ in which insect numbers have crashed. Each has corresponded to a major drought and period of extreme temperatures. So, in the course of 40 years we have seen a sequence of catastrophic events that will not have helped insect/invertebrate populations. The biggest ones I think were 1976/77, 1990/91 and several years in the early 2000s. Bearing in mind that nine out of the ten hottest years since 1910 have occurred in the past 17 years, climate change is something we have definitely got to look to as a major factor behind insect declines.

It is not, however, individual actions or events that really set the scene. Insect populations are remarkably robust, swinging back and forth as environmental forcing impacts upon them. An obvious example is the rise and fall of the holly blue butterfly whose numbers fall precipitously as parasite levels climb, but once the parasite peaks, its numbers crash and those of the holly blue climb again. Similar patterns can be seen in many species and can also be detected in response to droughts. For example, in 1947 it was remarked that the summer generation of the hoverfly Rhingia campestris failed to materialise. We have seen similar events from time-to-time in response to prevailing arid conditions.

My examples so far are individual species, but what happens when whole assemblages are hit by a particular environmental anomaly? Alan Stubbs always cites the impact of drainage at Wisley Common on its cranefly fauna as an example of how a major land-management change can impact an entire ecosystem. In that case, ditching caused changes in the water table and the cranefly fauna crashed; it never recovered because the change was profound and substantially irreversible. Anecdotally, Dipterists noticed a huge decline in wetland species in the 1990s, especially Sciomyzidae (snail-killing flies). This decline seems to have partially reversed during wetter periods. But, if conditions do not quickly recover towards the ‘norm’ the impact of the change will be longer-lasting and less reversible. Similarly, each autumn, our field meetings are punctuated with a general feeling that cranefly diversity is substantially down; anecdotally perhaps by as much as 30% since the 1970s.

So, why don’t we have the insects that used to occur? It seems to me that we can blame a combination of definable human impacts such as pesticides and intensification/loss of habitat. But, we must also put some blame at the insidious effects of climate change, which is also substantially an anthropogenic effect.

The catastrophic decline in insects highlighted by the Krefeld Entomological Society is simply an expression of the way the earth’s ecosystem is responding to anthropogenic perturbation. If we want to focus blame, we must do so on our entire community. It has become accepted that we will have access to ever-cheaper food, transport and consumer goods. There has to be a cost, and that may well be the demise of current ecosystems that are in fact our own life-support system!

The perils of licensing invertebrate collecting

A contributor to the BWARS Facebook group recently expressed surprise that there was limited control over who collects insects or other invertebrate specimens. The comment drew attention to an important issue that I think is poorly understood.

In the UK, we don't have a single law banning insect collection except by a few privileged individuals who can fight their way through masses of officialdom (i.e. a few academics). Yes, we do have a system whereby there is a need for a permit to collect from certain land designations. There is also provision to protect certain species that are vulnerable to the effects of collecting. Fortunately, the latter is fairly light touch but there are restrictions that could cause problems where species are very similar. In addition, some landowners, such as the National Trust and Forestry Commission, do have general permitting systems.

There is also a growing question of whether collected specimens are accompanied by permits in order that they be accepted by museums? So, in fact we have quite a range of officialdom ourselves - it just that it is not unified and there are grey areas.

The drawbacks of permitting

For the serious entomologist permits can be a problem.

Until recently, I ran Dipterists Forum's summer field meeting. It is a Mammoth undertaking. At one time, these meetings tried to visit as many SSSI in the area visited. They relied on the then organiser (who was a Grade 7 in the Nature Conservancy Council) to organise all the access permissions. When the NCC was disbanded there was nobody to do this and it became increasingly difficult to run such meetings. There is a good two months’ work involved in securing access to sufficient sites to keep a team of 20+ Dipterists occupied for a week. It is not really a job that can be undertaken by a volunteer and' in my experience, it became very difficult to get help from Statutory Agency staff. I well remember spending several trips simply visiting the local offices each day to sort out permissions - so if you are paying £300 to £400 for a week away, you don't really want to spend your time cooped up in an office, ringing landowners!

The solution was to stop attempting to visit SSSI and to concentrate on land where one could secure blanket access permission: The Wildlife Trusts, Forestry Commission, National Trust and local National Nature Reserves. Hopefully that job can be done in a day - but it is still a demanding job for a volunteer. Needless to say, I lost enthusiasm for the job of running field meetings and eventually bowed out of running such big events. Finding a replacement for such an onerous job is not easy and I doubt that such meetings will carry on for that much longer.

This situation highlights a critical issue: most of the UK's biodiversity data comes from volunteers and the highest quality data come from those few specialists who do collect specimens. If we don't have a practical way of managing permits then we will probably lose access to a lot of new data and will see a decline in the numbers of specialists who are prepared to provide information to UK data users. If one looks for an analogous situation, it is worth thinking about the difficulty of obtaining collecting permits for some European countries. Do they have a wealth of data on difficult taxa? Simple answer: No! Conversely, the UK is one of the richest countries for biodiversity data, including for many difficult groups.

It seems to me that the comparison tells an important story. If you impose a strict permitting system you will lose access to data. So, the moral of the story seems to me to be that if you want information it is essential to make the system simple as possible.

Flies in bat roosts

I wonder if there is scope for Dipterists and bat groups to link up in order to get a better picture of the flies that occur within such places?

We know really very little about the distribution of bat flies Nycteribiidae and Dipterists very rarely see them. There are other flies, however, that seem to be closely associated with bat guano, especially Heliomyzidae. Again, Dipterists don't see them, especially as access to bat roosts is restricted.

Maybe there is somebody in the 'batting' community who would be interested in taking on a project to look at what can be bred out of bat guano? Alternatively, perhaps we could find a Dipterist who would be prepared to accept samples of bat guano and try to breed flies from it? I'm not specifically volunteering, but would be interested in trying a limited number of samples to see how practical such a project might be.

Any takers amongst the bat groups to help supply guano, and a Dipterist or two to try breeding from it?

HRS training courses

Although I have written on the subject of training on several occasions, I don't think I have set out, in detail, what we offer and how we deliver our courses. There is an article in Antenna, but I guess that very few people will have read that or even noticed it! So, perhaps I need to set out the basics:

Thanks to grants from the OPAL fund, Natural England and Dipterists Forum, the HRS (& Dipterists Forum) has the capacity to travel the length and breadth of the country delivering training courses to local groups. Quite simply, we fill the car with 12 microscopes plus camera microscope plus 5 store boxes of specimens and whatever other equipment that we need for the trip (Computer, books, handouts etc). Normally we have to travel the day preceding the course so we are usually faced with two nights in a B&B (it can be more when we go to far-flung corners such as Orkney and Shetland).

We offer three main courses:

• Introduction to Hoverflies: an entry-level course designed to take the absolute novice through the basics of comparative anatomy and interpreting keys using Stubbs & Falk. This is a two-day course that is trimmed down from the three-day course that we run each year for the FSC and Manchester Metropolitan University.
• Intermediate Hoverflies: a two-day course that concentrates on difficult genera, especially Cheilosia and Platycheirus. It is aimed at people with a reasonable level of experience who have previously done our introductory course.
• Introduction to Diptera. We have run various permustations, including a straight four-day course for the FSC, two consecutive weekends for the Beds, Cambs and Northants Wildlife Trust, and a two-day version such as we ran for the London School of Hygiene & Tropical Medicine. This course is the most problematic because we don't think two days are enough, but it is difficult to deliver over a longer time-frame without reducing the numbers who might want to attend. 

How the courses work?

Our courses have evolved over the past 25 years and are now wholly based on a set of specimens that allow us to give each student the same specimen. It means that I maintain a huge volume of specimens in a total of ten store boxes (a lot of shelf space in my house!). This allows us to run courses in the winter, which is our preferred approach because it reduces the impact on our summer field itinerary. Our courses are limited to a maximum of 12 participants and we won't travel long distances for any fewer than 8 participants.

We provide a series of powerpoint presentations that include discussion of issues such as maintaining and managing a collection, field craft and a plethora of anatomical features. In essence what you get is a solid module in comparative anatomy. However, it is neither stuffy, nor dull. If you are interested in Diptera there will be something there for you and you will get the best opportunity possible to develop skills.

Day one starts with an introductory talk followed by a series of sessions in which we guide you through the keys, including group sessions before letting people loose to work at their own pace. We think this is essential because it makes sure that everybody gets attention and the critical issues are fully covered as a group.

As the weekend progresses, we punctuate the sessions with presentations to explain anatomical issues and of course to cover requisite skills in curation, recording and field craft.

How much does it cost?

We charge at cost for fuel, accommodation and road/bridge tolls/ferries. We set a basic £15 per each (i.e. £30) per full day subsistence allowance (will adjust for part-days) and also make a charge (£6 per student) for some course handouts (introduction to Hoverflies). The charge is made as an invoice from Dipterists Forum and we in turn invoice Dipterists Forum for our costs. Basic costs where a 2 night stay is required and a drive of up to 600 miles will cost in the region of £300-£350 at current rates but will be higher for longer distances or if ferry crossings are required.

Logistics

We provide:

• Full set of specimens for the course
• Camera microscope, computer and presentations
• Set of 12 microscopes for students
• Course literature for students to retain
• Relevant text books (i.e. Stubbs & Falk) for loan during the course

Our requirements:

• Room capable of accommodating us plus 12 students, each with desk space of appx. 4' x 2' - we also need sufficient space to set out collections etc so usually between 16 and 20 standard stackable tables
• Powerpoint projector (and suitable surface to project onto - we can provide a screen but prefer to work with local facilities where possible - reduces the risk of loss of valuable items whilst travelling)
• Facilities for making refreshments
• 12 students - organised by you

Following a trip to Orkney where we found that 3 out of 8 of our expected group failed to attend, we won't run courses where the students don't pay anything towards the costs. We took this decision because we think that where courses are free it is more likely that you will get casual interest participants who won't use the course and may well not attend because they have no personal investment in it.

Booking

We usually organise our itinerary a year in advance, so we are looking to make bookings for winter 2018-19. We will probably restrict ourselves to a maximum of four courses next winter, somewhat dependent upon my health, so bookings may have to be provisional.

Changing recording demographics

When we took on the Hoverfly Recording Scheme (HRS) in 1991 the ways in which data were submitted and absorbed were utterly different from today. Likewise, the contact we had with recorders was also very different. Most people submitted records on cards or via a bespoke database such as RECORDER or MAPMATE. We did a great deal of the data entry and mainly communicated by letter or through the HRS Newsletter. Feedback was inevitably intermittent and we could control the pace at which we worked. Data entry was confined to the winter months, whilst we had the summer to do our own field work.

Scrolling forward 25 years, we have seen a paradigm shift in which databases have substantially disappeared from the scene, spreadsheets are the main way in which data arrive, and we now extract some data direct from posts on Facebook, Flickr, iSpot etc. We mainly communicate via the UK Hoverflies Facebook page and provide more permanent feedback on this blog. The HRS Newsletter continues and does reach some of our traditional recorders who don't 'do' social media. This shift is clearly illustrated in Figure 1, which was prepared by Stuart for his talk to the Huntingdon Flora and Fauna Society last night.

Figure 1. Sources of data arriving at the HRS, 1991 to 2018.

There has also been a remarkable change in recruitment of new recorders. There are several ways in which one can define a new recorder: the critical issue is probably to define those who genuinely make a regular or substantial contribution to the dataset rather than those one-off casual records that add lots of names but very few records. Thus, we can see from Figure 2 that until around 2006, the numbers of new recruits were relatively small; often below 30 per year. There are two reasons that explain the rise from 2006 onwards.

Firstly, we became a lot more active running training courses from around 2005 onwards. Initially we were constrained by the need to use venues where people brought their own microscopes or used those 'scopes provided at the venue. This constraint was removed in 2009 when a grant from the OPAL fund allowed us to buy 13 microscopes which we now transport to far-flung venues. So, we would like to think that our efforts to train and enthuse have had some impact.

Around the same time, iSpot and 'Wild About Britain' became available as a way for people to get help with identification of their finds. It encouraged a new photographic recording community and set the scene for much greater inter-active recording. In reality, interactive media have probably played a far bigger role in growing the recorder community, which is most obvious from Figure 2. This graph uses two different metrics to define a new recorder: one based on regular submission of 5 or more records yearly, and the other based on the total number of records submitted, with 250 as the threshold for a 'new' recorder. Both systems tell a similar story, with a clear jump in activity from around 2011 and a further jump around 2014 when the UK Hoverflies Facebook page really became established.

Figure 2. Metrics for defining 'new recorders'. The upper graph comprises the numbers of recorders in a given year, whilst the lower one illustrates recruitment of major contributors.

This year, we are pretty well up to date with importing data into the HRS database, so the figures for numbers of records yearly are almost 'real-time'. They tell a similar story to the numbers of recorders, but really highlight the impact of the Facebook group, which I think we can say with confidence has almost doubled the numbers of records entering the system (Figure 3). The total for 2017 is likely to climb a little more because we always see a slow trickle of records over the year after a big influx in January. Whether 2017 will ultimately overtake 2016 remains to be seen, but it is highly likely. I suspect we have a little way further to go before a new asymptote is reached, but my guess is that the new level of recording will probably lie somewhere between 60 and 70,000 records annually.

Figure 3. Numbers of records on the HRS database