Bioblitz 2 - The Hatching

Earlier in the summer I helped out with identification at a bioblitz, and one of the things I was given to look at was a cluster of pupae attached to an oak leaf. It didn't take long to work out that they were a species of small parasitic wasps in the genus Eulophus, but they needed to be reared to adulthood to be identified to species. So, that's what I did...

Now empty, the ring of pupae that surround the host caterpillar (removed), giving this stage of Eulophus the name 'tombstone pupae'.

Side view of Eulophus - note the metallic green colour, much reduced wing venation and long pale legs. The body, excluding legs, wings and antennae is around 2mm long.

Note the bulges on the mesoscutum just in front of the wing bases. The line around the bottom of a bulge is called the notaulix (pl. notaulices) and is only sharp in the front half. This is diagnostic of the subfamily Eulophinae.

The antennae are inserted level with the base of the eyes, not halfway up. This is one characteristic of the genus Eulophus.

The scutellum (the upper surface between the wing bases here) is only slightly convex, not strongly bulging. This is another characteristic of Eulophus.

More characteristics - the front coxae (basal segments) are pale and the mid coxae are metallic.

These (and some other hard-to-photograph) features mean that this species is Eulophus larvarum. It is common in the UK and has two forms - the spring form (April-June) and the summer form (June-August). The summer form has a pale spot near the front of the gaster (the broad or 'main' part of the abdomen) which is seen here.

The pale/yellow spot on the gaster showing this to be the summer form of E. larvarum.

This species is a parasite of the exposed caterpillars of moths in several families in the UK. Being so tiny they are often overlooked, but careful searxching may produce specimens and they were easy to both raise (in a  ventilated lidded pot) and (to my surprise) identify, using Askew (1968) which is now available as a free download - see below.


Reference

Askew, R.R. (1968). Handbooks for the Identification of British Insects 8(2b). Hymenoptera: Chalcidoidea Section b. RES, London. [free download here]

Unexpected egg-flies

Back in January, my wife showed me a blackbird egg she'd found in the garden. It looked whole, but was incredibly fragile and broke almost as soon as I picked it up, clearly already being cracked. I expected maybe a whiff of something nasty, but there was more going on than I expected...

Inside the egg... lots of invertebrate action.

Naturally, instead of saying 'yuk' and throwing it away, I had a closer look. The orange inveretebrates are mostly fly pupae plus a few larvae. The black shapes are pupal skins of something already emerged, and the large larva in the middle something else entirely. A quick look in Smith (1989) jogged my memory that the smaller ones were probably juveniles of the Psychodidae, also known as moth-flies or owl-midges. The larvae of many species are associated with decaying organic matter, so the inside of a failed egg is a plausible hiding/feeding place whether the goo insode is egg material or something else that had seeped in. Beyond that I couldn't tell, so I put them in a hatchery and waited. After not too many days this is what I found...

Pupae, pupal cases and adults of a psychodid fly.

In total there were 15 pupae and these soon started to emerge as adults. The small size, their shape, and their hairy/feathery wings mean they don't look like typical flies, but that is exactly what they are - as you can see below, they have a single pair of wings, the other pair reduced to drumstick-shaped balance-organs (halteres). Psychodidae are not an easy group to work on (especially if you are not that familiar with them), and identifiying the flies to genus, let alone species, would require time, a microscope, and a copy of Withers (1989). I won't go through all the steps, but here are a few key features:

There are two veins (dashed lines) between the two main forks in the wing veins (circled).

The arrow indicates the eye-bar - an extension of the eye above the antenna. The circle indicates the pale haltere mentioned earlier - yes, these realy are flies!

 The antennae are an important feature too, but take care when keying out genera and species...

The key asks whether the antennal segments are barrel-shaped or have an elongated stalk. These look barrel-shaped but...

...if you remove a segment you can see that the barrel-shape in this case is formed of hairs that hide the real shape - the dark segment clearly has a stalk.

So, after quite a bit of deliberation, this keyed out as the genus Psychoda. I'm less certain about the species (not only can they be difficult to separate, but the taxonomy of Psychoda needs to be revised), but it might be P. alternata (the stripy larva in the first photo matches this, as does the foul habitat). Withers (1989) doesn't list Hampshire for this species, but the Psychodidae are under-recorded, and he does mentioned Wiltshire and Sussex, so it wouldn't be a surprise. That's enough for now - I shall leave you with some more juveniles, feeding/hiding merrily in the goo...

Psychoda - three pupae (complete with a pair of pupal horns for breathing) and a larva.

References

Smith, K.G.V. (1989). An Introduction to the Immature Stages of British Flies. Handbooks for the Identification of British Insects 10(14): 1-280.
Withers, P. (1989). Moth Flies. Diptera: Psychodiae. Dipterists Digest 4: 1-83.

This is why I geek those beetles

If you are a regular here, you'll know I spend a lot of time peering closely at small invertebrates in order to identify them, like here. For those interested in taxonomy and morphology (like me), that can be an end in itself - I find small creatures fascinating and I like to know what they are. I geek them, and do so proudly - plus I'm a professional entomologist/ecologist so there's the academic-kudos and getting-paid aspects. However, there is more to it than that.

I have been asked more than once why we need to identify species - and it's a fair question; after all, the beetles don't care whether we can name them, and individual ones would probably prefer not to be fatally sampled for the greater good. However, without identification (which often requires a dead specimen), there can be no survey, monitoring or collection of distribution data; and without these, we don't know what needs conservation effort. In an ideal world, their habitats would be fine, biodiversity would not be threatened, and conservation (if needed given the previous points!) would have limitless funding. Sadly these things are very very much not the case. So, samples are taken, species are identified (along with date, location etc) and data sent to recording schemes/centres, or now added to online systems such as iRecord to be validated by hard-working volunteers such as myself...

Once the data has made its way to the recording scheme database, it can be downloaded, interrogated - in short, used. This could be for any number of purposes - planning, research, amatuer interest, and so on. However, during the winter of 2013/14 I was lucky enough to be contracted to use this data to write a status review of the Chrysomelidae (leaf beetles), the group I specialise in. This meant looking at the change in distribution of all the British species and allocating them to categories such as 'Least Concern', 'Endangered' and 'Vulnerable'. Thus, scarce and threatened species could be identified and highlighted with extra information focusing on these, such as summaries of habitats, distribution, threats and conservation measures. This is important as it will inform conservation efforts, survey work, policy decisions and other activities. It's also part of a wider project with different specialists covering their groups of choice such as Carabidae (ground beetles) and is a major update to status review work published in the 1990s (e.g. Hyman & Parsons, 1992) some of which is now considerably out of date.

I won't go into any more detail here, but if you want to look at the report, it's called A review of the scarce and threatened beetles of Great Britain: The leaf beetles and their allies and is free to download here along with data covering the key species.

Reference

Hyman, P.S. & Parsons, M.S. (1992). A review of the scarce and threatened Coleoptera of Great Britain 1. JNCC, Peterborough.

The moth-mummy returns

I've written about parasitic braconid wasps before, and you know, I probably will again - because they are fascinating. This one hatched recently from the mummified remains of what I think is a small noctuid moth larva that I found in our garden, possibly one of the Xestia or Noctua species.

Mummified remains of an unfortunate moth larva, showing the legs

Mummified moth larva showing the wasp's exit hole at the rear. The material sticking the mummy to its substrate can be seen beneath the head.

As you've gathered, this is an internal parasite (parasitoid) - in this case probably Aleoides borealis or something taxonomically close to it (written as "Aleiodes sp. near borealis"). This kills the host before it is fully grown - it then changes the host behaviour to ensure it adopts a parasite-frindly position, after which the parasitoid makes a slit in the host on the underside near the head. Through this slit, it produces a sticky fluid which glues the host in place. However, I don't only have an empty husk to show you - I collected the mummy before emergence, and this is what appeared in my hatchery.

Aleiodes sp. near borealis

Head (with ocelli) of Aleiodes sp. near borealis

Abdominal pattern of Aleiodes sp. near borealis

Parasitic Hymenoptera are notoriously tricky to identify, but I think this is a reasonable conclusion - as ever, I am happy to hear from anyone who has a better idea what it is!

Springtime beetles, legs go spring

Having a garden pond means occasionally finding dead things floating. No, not hedgehogs or other larger fauna - the sides are profiled so that mammals can get out - but sometimes incautious invertebrates drown. Naturally, if they look interesting (and haven't been eaten by pond skaters and other small predators), I fish them out for a closer look. When I saw a flea beetle (in the Chrysomelidae, my specialist group - they are in the tribe Alticini within the subfamily Galerucinae) I identified it easily enough as Longitarsus pellucidus, a common species, though it's always worth checking. It lives on bindweeds (Convolvulaceae) which are growing near the pond so presumably jumped into the water by accident when disturbed by a spider, bird, cat, human or other potential threat. However, it did give me an opportunity to look at why flea beetles are so named.

Longitarsus pellucidus - the swollen himd femora can be seen, as well as the elongate tarsus that gives it its generic name.

The hind femur in flea beetles is swollen to accomodate jumping muscles and the 'metafemoral spring' which is visible through the cuticle as a slightly paler comma-shaped structure taking up much of the inside of the femur.

Hind femur and metafemoral spring of L. pellucidus.

The spring is a long-oval chitinous structure coiled much like a loose fist. Muscles squeeze the spring closed and then a 'catch' is released and the stored energy is released, extending the leg so the beetle can jump.Here you can see a ligament extending from the spring to the tibia so the leg is folded when the spring is compressed. This mechanism differs from that in fleas which have a blob of resilin (a natural rubber) which is compressed instead of a spring. Although fleas may be more familiar for their leaping ability, some alticine beetles are actually able to jump comparatively further, and of course some of these beetles are no bigger than a large flea - smaller beetles jump further relative to their size (Schmitt 2004). Also, the spring may be useful for identification and for grouping species taxonomically by looking at similarities and differences in the form of their springs. However, this is not a mainstream technique, largely because of the difficulty of dissecting out the spring and the lack of readily available published material forming a guide to identification this way, although there is useful information in Furth (1988) along with images and drawings from various species.

References

Furth, D.G. (1988). The jumping apparatus of flea beetles (Alticinae): the metafemoral spring. In: Biology of Chrysomelidae, eds. P. Jolivet, E. Petitpierre & T.H. Hsiao, pp. 285-297. Kluwer, Dordrecht.
Schmitt, M. (2004). Jumping flea beetles: structure and performance (Insecta, Chrysomelidae, Alticinae). In: New developments in the Biology of Chrysomelidae, eds. P. Jolivet, J. Santiago-Blay & M. Schmitt, pp. 161-169. SPB, The Hague.

Blisters in the dry

As spring has indiced some rapid plant growth, I was doing some weeding in our small gravel/alpine garden, including pulling a few unwanted hairy bitter-cress Cardamine hirsuta that were bullying my less-aggressive plants. During this, I noticed some white blisterlike structures on the underside of many of the leaves - not leaf-mines, but something more fungal. A quick look in Ellis & Ellis (1997) told me it was, as I suspected, the 'brassica white rust' Albugo candida.

Albugo candida on Cardamine hirsuta

Close-up of A. candida on C. hirsuta - the widest part of the leaf here = 6.5mm. The leaf margin also shows some small bristles - despite the common and scientific names, C. hirsuta isn't very hairy, or hirsuite.

C. hirsuta is very similar to wavy bitter-cress C. flexuosa but the flowers only have 4 stamens (6 in C. flexuosa) and C. hirsuta tends to be found in drier locations. In this case the plant identification isn't hugely important as A. candida is found on a range of Brassicaceae, but many microfungi have a more specialised and narrow relationship with their host plant/s so (as with galls and leaf miners) it is usually essential to identify the plant.

C. hirsuta flower with 4 stamens.

Although A. candida is generally called a fungus or microfungus, technically it is a fungus-like 'water mould', one of a group of plant pathogens in the class Oomycetes of the phylum Heterokontophyta within the kingdom Chromalveolata (i.e. not the kingdom Fungi). The taxonomy is still a matter of debate (there are several competing versions and research is ongoing) but they are more closely related to photosynthetic organisms such as brown algae and diatoms. The class also includes some serious plant diseases such as late potato blight (Phytophthora infestans, cause - socio-economic factors aside - of the Irish potato famine of the 1840s) and sudden oak death (P. ramorum).

Reference

Ellis, M.B. & Ellis, J.P. (1997). Microfungi on Land Plants: An Identification Handbook (2nd ed.). Richmond, Slough.

The beetle is dead, long live the beetle

The decline of the leaf beetle (Chrysomelidae) Chrysomela tremula is well known (e.g. Cox, 2007; Hubble, 2012), even though the causes of its probable extinction in the UK are not understood - possibly the decline of coppicing and/or a side-effect of insecticidal spraying. The last known record was from Warwickshire in 1958, so when its rediscovery was reported relatively recently from purple willow Salix purpurea in Cambridgeshire (Mendel & Hatton, 2012), there was much rejoicing. Then, shortly afterwards, the authors realised that this had been a misidentification and they had actually found C. saliceti, a species never before found in Britain (Mendel & Hatton, 2013). So, C. tremula remains probably extinct but we do have a new species. This doesn't mean C. saliceti is non-native - it is very similar to C. tremula and may simply have been overlooked - after all, their separation was tricky enough to briefly trick some very experienced entomologists until another one noticed and the error was rectified - which is how science works...

Then after a discussion at the recent Coleopterists' Day in Oxford, Howard Mendel was kind enough to post me a couple of specimens of the new species as I had never seen one.

Chrysomela saliceti approx 9.5mm long.

Chrysomela saliceti under different lighting to more clearly show the punctures on the pronotum and elytra.

The trick is to separate the two species - especially in case C. tremula is still hiding somewhere (or re-appears from the Continent). A paper about this is planned, but until then, there are two key features:

• The claw-bearing tarsal segment (two apical teeth on the underside in tremula, absent in saliceti).
• Dissection of males to check the tip of the aedeagus (equivalent of a penis).

Tarsus ('foot') of C. saliceti - the claws are visible but no teeth on the underside.

The aedeagi of the two species for comparison.

References

Cox, M.L. (2007). Atlas of the Seed and Leaf Beetles of Britain and Ireland. Pisces, Newbury.
Hubble, D. (2012). Keys to the Adults of Seed and Leaf Beetles of Britain and Ireland. FSC, Telford.
Mendel, H. & Hatton, J. (2012). Chrysomela tremula Fabricius (Chrysomelidae) rediscovered in Britain. The Coleopterist 21(3): 132-135.
Mendel, H. & Hatton, J. (2013). Correction: Chrysomela saliceti Suffrian (new to Britain) not Chrysomela tremula Fabricius (Chrysomelidae) in the cambridgeshire fens. The Coleopterist 22(1): 19.
Warchałowski, A. (2003). The Leaf-beetles (Chrysomelidae) of Europe and the Mediterranean Area. Natura Optima Dux Foundation, Warsaw.

Bum-bursting mummy-wasps

Yes, you know it from the title - it's parasite time. If I ever feel that tiny beetles are too easy to identify and I fancy a challenge, the parasitic Hymenoptera are the group of choice - huge numbers of species, tiny differences between them, and few accessible keys. Yay. To make sure I don't get lazy, I have a hatchery where pupae (for example those I dislodge cutting firewood, mending the garden fence etc) are kept to see what they turn out to be as adults, identified and maybe even released. Sometimes other things turn up, for example this mummified larva of the knot-grass moth Acronicta rumicis on a bramble stem.

Mummified larva of Acronicta rumicis

It's worth noting that this is not a pupa - it is the moth larva's empty skin stuck to the stem by the dark brown sticky substance you can see just behind the head. This 'glue' is released by the fully grown wasp larva by cutting a slit in the underside of its host. I have had the 'mummy' in a hatchery for several weeks, but this morning I found an exit hole at the rear of the dead moth larva, and a lively adult wasp scuttling and flying inside the container.

Acronicta rumicis 'mummy' showing the parasite's emergence hole

The parasitic wasp cooled down and quiet. 1 square = 5mm.

So, time for identification. It's a wasp of some sort within the superfamily Ichneumonoidea. However, the abdomen isn't on a thin stalk and the wing venation indicates it is of the family Braconidae rather than Ichneumonidae.

Braconid wasp showing wing venation

For comparison, the wing venation of the braconid Aleiodes praetor, from Huddleston & Gauld (1988)

Now, it's worth noting that there is no guide to British braconid genera or species. Shaw & Huddleston (1991) gives a key to the subfamilies, but beyond that, identification requires a variety of more-or-less obscure journal articles in most cases, and the taxonomy has undergone a lot of revision. Fortunately however, this is (for a braconid) a relatively straightforward specimen. Firstly, the subfamily key takes it to Rogadinae and secondly, the wing diagram above matches the specimen closely because (handily) they are the same - Aleiodes. In the most recent checklist (Broad et al. 2012) there are 37 species of this genus in Britain and all are believed to be solitary (unlike many braconids where many parasites develop in a single host, the best known probably being Cotesia glomerata AKA Apanteles glomeratus). Although species identification is challenging, there are some clues. For example, the first two abdominal segments (blue arrows in the photo below) have longitudinal ridges running along the middle of their upper surfaces and this is typical of the common species A. praetor.

Aleiodes sp. showing ridges on the first two abdominal segments (blue arrows)

I couldn't check this tentative ID myself - at least not without accumulating some articles I don't have ready access to and/or visiting a museum collection (even online there is very little in the way of images, keys and so on). So, I passed this onto some braconid specialists who have confirmed it isn't A. praetor (not orange enough, though there are more technical ID features required too!) and I hope I'll get a definite species ID soon. Until then, I await whatever else appears in the hatchery...

Ventral view of Aleiodes showing orange legs with some black areas, and orange mouthparts.

References

Broad, G. R., Shaw, M.R. & Godfray, H.C.J. (2012). Checklist of British and Irish Braconidae (Hymenoptera) [30th April 2012 version]. Free download here.
Huddleston, T. & Gauld, I. (1988). Parasitic wasps (Ichneumonoidea) in British light-traps. The Entomologist 107(2): 134-154.
Shaw, M.R. & Huddleston, T. (1991). Classification and Biology of braconid wasps (Hymenoptera: Braconidae). RES Handbooks for the Identification of British Insects 7(11): 1-126. Free download here.

What's in the box? Two of one, one of another (part 2)

Yesterday, the answer was Oulema melanopus - today I'm tackling the other two, much tinier beetles. They both look like the one below and were tentatively identified from dissection as male Aphthona euphorbiae. Why tentatively? Well, they can only be separated from closely related species (not to mention some taxonomic confusion with these which I might write about if it's ever resolved) by looking at the aedeagus - the male genitalia - and in these specimens they don't look quite like the standard images in books or on websites like this which are useful for comparison.

A specimen of Aphthona, possibly A. euphorbiae - it is around 2mm long, not including legs and antennae.

Looking at specimen #1, here's the aedeagus:

Aedeagus of A. euphorbiae.

This one's straightforward - it's fairly stubby and although it doesn't widen towards the end (the top), it has got the small, broad blunt tip on the otherwise more-or-less semicircular end. Definitely A. euphorbiae, so onto specimen #2:

Aedeagus of A. euphorbiae.

This one's similar, but under the microscope looked more elongate although the tip is correct. It's probably A. euphorbiae but with the possibility for confusion with A. atrovirens or A. ?atratula (the '?' indicates uncertainty about it's identity/taxonomy), it can be worth checking even common species as this can sometimes help unravel such difficulties, though in most cases it is simply the usual range of variation between individuals even in diagnostic features such as the aedeagus. Anyhow, time for a side view:

Aedeagus of A. euphorbiae.

The curved (but not too curved) form confirms it is A. euphorbiae - a common species but good practice in investigating features that can be tricky in specimens showing a little variation from the norm.

That's enough beetle-nerding from me. Back soon with... hmmm, haven't decided yet...

What's in the box? Two of one, one of another (part 1)

While at the annual Coleopterists' Day at the Oxford Uni Museum of Natural History last weekend, I was handed a small wooden box with three pinned beetles in it. If you are an entomologist, this will be familiar as specimen-swapping is an important way of seeing varied specimens and passing on tricky beasties to specialists for identification. Not that getting a box of beetles was the real reason I was there - there's a really good entomology library to rummage through plus I gave this talk to my fellow beetle-nerds, now published in a slightly more formal version as Hubble (2013).

Box of beetles - two Aphthona on the left, and a larger Oulema.

So, to the beetles - they'd all been tentatively identified, but were passed to me for confirmation. I started with the larger one, 'a female, probably Oulema melanopus'.

Pinned female Oulema - note the blue-black head and elytra and red pronotum.

The female genitalia had been dissected and preserved in a drop of clear mountant. The important part is the little knot bottom-right where 'sd' = spermathecal duct.

An extract from Cox (1995) comparing the female genitalia of O. melanopus and O. rufocyanea, two very closely related species.

Looking at the images in Cox (1995), and the equivalent in Hubble (2012), it is clear that Figure 6 is close to the specimen here, including the short spermathecal duct and arrangement of other tubules. So, this is O. melanopus - good practice at a sometimes-tricky species group aided by some excellent dissection (not mine!). This may be even more useful given that unpublished and ongoing Swiss work on specimens of O. melanopus has shown that a small number of them turn out to actually be O. duftschmidi. There's no indication that this latter species exists in the UK, but it has a Western Palaearctic distribution so it's not impossible and I'll be keeping an eye out...


References

Cox, M.L. (1995). Identification of the Oulema 'melanopus' species group (Chrysomelidae). The Coleopterist 4(2): 33-36.
Hubble, D. (2012). Keys to the adults of seed and leaf beetles of Britain and Ireland. FSC, Telford.
Hubble, D. (2013). Progress report on the Chrysomelidae recording scheme. The Coleopterist 22(3): 103-109.

Insect slaves in a fungal nation II

I've written about the fly-killing fungus Entomophthora muscae before, way back near the start of the Ecology Spot. In that post I covered the behavioural changes it causes, and a bit about how the fungus does this (or rather, how little we understand this). I don't want to repeat it here (it's all in the original post), but when I found another yellow dung-fly (Scatophaga stercoraria) infected with E. muscae, (well, certainly this fungal genus, and E. muscae is by far the most likely) this time in our garden, I felt an update was in order.

A dead yellow dung-fly Scatophaga stercoraria infected by Entomophthora muscae. Note the typical posture adopted shortly prior to death - head down, abdomen up, wings spread - this maximises the spread of fungal spores.

With the Harvard research programme (looking at how the fungus infects hosts and changes behaviour) having closed, it does not seem that this thread is being actively pursued at present (if this isn't the case, please do let me know and I'll update this post). There has however been recent work looking at the evolutionary history of the fungus (e.g. Gryganskyi et al. 2013) and taxonomic research by Humber (2012) raises the group to full phylum status.

More on this fascinating, if often overlooked, fungus undoubtedly to come...


References


Gryganskyi, A.P., Humber, R.A., Smith, M.E., Hodge, K., Huang, B., Voigt, K. & Vilgalys, R. (2013). Phylogenetic lineages in Entomophthoromycota. Persoonia 30: 94 -105.

Humber, R.A. (2012). Entomophthoromycota: a new phylum and reclassification for entomophthoroid fungi. Mycotaxon 120: 477-492.

Cretaceous Crato creature 2

Though I do look at a lot of invertebrates, I rarely delve into palaeontology - however, a little while ago I did look at a bug from the Crato Formation (about 110-125 myo) in Brazil. I recently went shopping online again and found another one listed only as an 'insect' and not at all expensive, so (as the images looked fine) I decided to go for it and see if I could identify it myself. This is what appeared:

My 'new' Cretaceous Crato insect

It is by no means a large insect - the body is about 12mm long, the cerci (or 'tails') about 15mm if straightened, and the wingspan around 18mm. Using Bechly (2007), it didn't take long to determine that this is a mayfly, an adult or almost-mature 'subimago', probably of the family Leptophlebiidae. Apparently it is found reasonably often, but its taxonomic position is unclear - it may even be in a different family and is known simply as 'species 1'. So, that's as far as my identification can go - basically, it's a mayfly but beyond that nobody really knows. However, this doesn't mean its features can't be examined more closely...

Cretaceous mayfly: Leptophlebiidae (?) sp. 1

The head, thorax (orange and fairly uniform) and abdomen (speckled with pale pimples) can be clearly differentiated and four of the legs are visible, indicated by green arrows. The abdominal segments and midline, though slightly deformed are also visible (see the drawing below) as are the large forewings. The dark line extending top-left may be another leg - it's certainly about the right size.

Right forewing of Leptophlebiidae (?) sp. 1

The front margin of the wing is well preserved, along with sections of some of the veins radiating from the base, and some areas of the wing membrane itself. Not bad for its age... I think the outline suggested here is quite accurate as the shape is similar to other specimens, though maybe a little of the hind edge is missing.

The pair of long cerci, typical of this species (well, taxon - it might be one of several similar species) - note the thickened bases.

So, having investigated the main features, I decided to follow the methodology of other palaeontologists and produce a line drawing to try to elucidate the detail without the distraction of mineral colours and textures - these are useful when looking at some features, but a hindrance for others. By photographing, printing, tracing and scanning, this is what I came up with:

Line drawing of my specimen of Leptophlebiidae (?) sp. 1

Personally, I'm quite happy with this - although the wing membranes (for example) are lost here, the body segments are a little clearer and I think a sense of the overall level of preservation is clear e.g. the slight fragmentation of the cerci. Such specimens are generally given a catalogue number including an abbreviation of the museum they are in e.g. NHM 23438 would be specimen 23438 in London's Natural History Museum; maybe this mayfly should be DSH 00002, the second fossil insect in my collection of curios...

To finish, it's worth noting that the Leptophlebiidae are still around - there are about 2000 species worldwide, including 6 in Britain, though they have 3 cerci (one reason why the species here is of uncertain family), and the larvae have forked gills on their abdomens giving them their common North American name of 'prong-gilled mayflies'.

Reference

Bechly, G. (2007). Insects of the Crato Formation. In: Martill, D.M., Bechly, G. & Loveridge, R.F. (eds.). The Crato Fossil Beds of Brazil: Window into an Ancient World, Cambridge UP, pp. 142-426.

Ciids of change

Time for another tiny invertebrate today - not on a carrot, or among fragments of dead wood, but in an old Ganoderma bracket fungus attached to an old stump waiting to be cut up in our wood store. It clearly had small holes bored into it and there are many fungus-feeding invertebrates, so I had to investigate what lay within - the first thing that popped out was this small (approx. 2mm long) beetle larva...

Small (2mm long) beetle larva found in a Ganoderma bracket fungus

Initially I wasn't too sure what this was - a beetle certainly, but which family? It's almost certainly a 1st instar larva going by the lack of sceloritisation (darkening and hardening of chitin) which makes identification harder as many potentially useful features may be poorly developed. Superficially it looks similar to the Cleridae, but the hairs here are longer and sparser, and the tail 'horns' (cerci) in clerids are incurved rather than upturned. They are also found in carcasses or under bark rather than in fungi. However, although I was certain it was not a clerid, I did start my search among families that are systematically/taxonomically close to the Cleridae.

Fortunately, my first choice turned out to be the right one - the Ciidae, a family of tiny (1-4 mm long) beetles associated with fungi, especially old, decaying brackets and other wood-encrusting forms. They feed on the fungi and several species can sometimes be found in a single fruiting body. As well as being small, the adults are all black or brown, and morphologically very similar - as such they are generally considered to be a 'difficult' group to identify. This is true up to a point as relatively high magnification is needed, x60-x80 or more according to Cooter & Barclay (2006), and there is no easily/cheaply available up-to-date key to the British species - the best is currently Lohse (1967), though there is, I believe, a key currently being worked on. The pair of upturned cerci is typical, and even mature larvae are only weakly sclerotised (there would be more around the head and cerci).

As for which species it is, that's a bit of a guess - I'm not certain the larvae of all species have even been described, but Cis nitidus is a common and widespread species associated with old Ganoderma brackets, so is a likely candidate. Also, given the lack of information on ciid larvae, this is a good opportunity to look at some key features:

Ventral view of the head of the ciid larva - the small brown mandibles are visible, and an antenna (the other appears broken) is indicated by the arrow. It is unclear whether the larva is blind - there are faint indications of what might be ocelli (simple light receptors) but this remains uncertain.

Leg of the ciid larva - the middle left one is indicated by an arrow and bears a pair of tiny claws at the tip (the best focus I could get in the photo, but clearer under the microscope)

The posterior of the ciid larva with a pair of brown, upcurved cerci - also note the bristles which presumably have sensory and/or anti-predator functions.

Beyond this, I would need to raise larvae to adults for identification. If searching for Ciidae, it is important to only take small samples, e.g. from the edge of a fungal fruiting body, as searching is essentially destructive. In this case the bracket is on firewood and therefore has been removed and placed in a container to see what emerges - certainly better than burning it, and if anything interesting appears, it'll undoubtedly be posted here.

Lastly, if you do intend to investigate the Ciidae, it's worth remembering that entomologists have argued over the correct name for this family - Ciidae is now widely used, but you might find it called Cisidae, Cissidae or Cioidae...


References

Cooter, J. & Barclay, M.V.L. (eds.) (2006). A Coleopterist's Handbook (4th ed.). AES, Orpington.
Lohse, G.A. (1967). Familie: Cisidae. In: Freude, H., Harde, K.W. & Lohse, G.A. Die Kafer Mitteleuropas 7, pp. 280-295. Goecke & Evers, Krefeld. [In German]