New British tree-moth combo?

While walking in Southampton's parks a couple of days ago, I noticed the impressive Cork Oak (Quercus suber) that grows near the Titanic memorial. As you can see, it's a fine multi-stemmed specimen with the deeply creviced corky bark you would expect, and evergreen leaves with small, short-spined lobes.

Cork Oak (Quercus suber) in East Park, Southampton

Cork Oak (Quercus suber) bark - definitely corky!

Leaf of Cork Oak (Quercus suber) - note the small spined lobes.

Not all the leaves were so pristine however - some had brown patches which, on inspection, were clearly leaf-mines. As Q. suber is non-native and only found where planted such as in this city park, I felt it was worth investigating in case something interesting was present. This is what I found:

Q. suber leaves with mines (spines/lobes rolled inwards and hence not visible)

Mine on Q. suber leaf. The red arrow points to an exit hole. The black arrow points to another hole wihich might be an entrance, or simply an artefact of drying/curling.

Mine on Q. suber leaf. The lighting angle has been changed and the main gallery is clearly visible running from right (by the petiole) to left.

Q. suber leaf showing little evidence of the mine, unlike the upper surface where it is clearly visible.

Backlit Q. suber leaf - the mine is largely full of frass, though the section leading to the exit hole is visible as a short white part of the gallery near the bottom.

So, the mine can be described, but can it be identified? There are numerous leaf-mining invertebrates recorded from Quercus spp. in Britain, but few from evergreen species (which are non-native), and most of those are from Q. ilex. One thought was that it might be Ectoedemia heringella (a moth of the family Nepticulidae which produces multiple mines and can be common in the Southampton/Solent area) but looking here and in Heath (1976), its mines are narrower and more tightly convoluted ('wiggly'). However, it does match Stigmella suberivora (also Nepticulidae) as seen here and again in Heath (1976), plus a brief description in Emmet (1988).

If this is the case, it is an interesting find because, as far as I am aware, although S. suberivora is found on Q. suber in continental Europe (hence the specific name), it has only been recorded from Q. ilex in Britain according to both Ford (1949) and Emmet (1988). Its identity is currently under discussion on iSpot, although to be certain, it may be necessary to revisit the tree to find eggs and/or larvae and raise adults for identification. If confirmed as being S. suberivora on a previously unrecorded host for Britain, I'll post an update here (and undoubtedly write it up more formally for publication!)

References

Emmet, A.M. (1988). A Field Guide to the Smaller British Lepidoptera (2nd ed.). BENHS, Reading.
Ford, L.T. (1949). A Guide to the Smaller British Lepidoptera. SLENHS, London.

Heath, J. (ed.) (1976). The Moths and Butterflies of Great Britain and Ireland. Volume 1: Micropterigidae - Heliozelidae. Blackwell, Oxford / Curwen, London.

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]

That carrot mite be past its best

If you are a regular here, you'll have noticed that I've been peering at the very small recently, and today is no exception. While sorting through our larder, I found a rather mouldy and sad-looking carrot hiding at the bottom of the veg basket. Normally it would be dsetined immediately for the compost, but the mould was big and fluffy, and you never know what might lie within...

Mould on an old and shrivelled carrot (yes, it is a carrot...)

Close up the mould consists of white and green-grey fibres with clumps of spores - but note the small invertebrates, the largest being around 0.5mm long

Zooming in, the fungal fibres/hyphae are clearer, and the invertebrates are 'mould mites' of the genus Tyrophagus

Although I don't intend to look at the fungus in too much detail, a simple slide preparation shows the typical fan-like arrangement of spore-bearing 'conidiophores' at the end of the stalks - either Penicillium or Aspergillus (something I wrote about here albeit on a rather different substrate).

Tiny greenish spores of Pencillium or Aspergillus on branched conidiophores (x400)

The mites are typical of Tyrophagus 'mould mites' (probably T. putrescentiae, possibly T. longior) which feed on moulds - as you can see, they are pale and shiny (not unlike animated jelly-beans) with long sparse sensory hairs. They can be associated with damp conditions and respiratory or skin ailments (e.g. where houses have large damp, mouldy patches), although in this case our larder is dry and I expect they came in with soil, so hopefully throwing the carrot out and cleaning the basket will get rid of them! Although mites are generally familiar as a broad group, their finer structure tends to be less familiar unless you are reader of acarology (mite-science) webpages and books, so, zooming in will hopefully provide some useful insights.

Dorsal view of Tyrophagus, approx 0.5mm long. Note the long hairs, eight legs, and triangular arrangement of mouthparts.

Ventral view of Tyrophagus. Some internal structures are visible such as the genital area (central orange-brown patch), ovary (smaller orange-brown patch to the right), reproductive tract (dark patches either side of the ovary) and eggs (the oval structures towards the outside). The other blurry dark forms are branches of the gut.

A cleared specimen of Tyrophagus. The pinkish leg segments are clearly visible (as are the mouthparts to a lesser extent) and the orange ovary is also obvious.

The mouthparts are also worth investigating - being arachnids, mites have paired jaws (chelicerae) with a small fang.

Ventral view of mouthparts of Tyrophagus. The paired jaws (chelicerae) can be seen, each ending in a small fang. The pharynx is just visible as a faint elongate structure running off to the right. Note the mould spores stuck to the mite (here I speculate that as well as wind-dispersal, the spores may be spread by mite movements).

Dorsal view of the rostrum of Tyrophagus, above the chelicerae. Sensory features are also visible here, including socketed setae (green arrow) and what appear to be ocelli (red arrows).

Colloff (2009) shows how little is known about the sensory apparatus of mites - they certainly don't have eyes that can form an image but which have simple ocelli as photoreceptors is unclear. I can not find Tyrophagus listed as having ocelli, but while Woolley (1988) only mentions the family Saproglyphidae as having them, this specimen does appear to (and is in the Acaridae). However, the long setae are more important sensory structures. The socket is a membranous receptor and while they undoubtedly have a mechanical function (e.g. sensing touch, vibration or similar), at least some have pores with research suggesting (though a little tentatively) that they may also sense chemicals such as pheromones (Leal & Mochizuki, 1990)

Seta on the dorsal body surface of Tyrophagus, again showing the socket.

Moving on from sensory structures to locomotion, the leg segments, including inter-segmental membranes, are clearly visible in some of the previous photos. However the 'foot' (i.e. the tip of the last tarsal segment) has some interesting structural features.

Tip of the last tarsal segment of Tyrophagus. Note the flanged expansion and single small claw (curving towards the camera here).

Lastly, I want to revisit the egg seen inside the whole mite in one of the first photos above; note that mating is rear-to-rear as seen in Fig. 1c here as well as below) and the male is noticeably smaller than the female and doesn't have the orange ovary.

Mating pair of Tyrophagus

Large, well-developed egg of Tyrophagus removed from a female. This appears sculptured whereas the few available images of eggs are smooth apart from microsculpturing. Therefore, this may have a covering that is lost upon laying.

 That is where I'd like to leave mite morphology/anatomy, for now at least, although I suspect they'll appear on my radar again at some point.

Even moulds can be attractive - a spore-covered pom-pom!

References

Colloff, M.J. (2009). Dust Mites. CSIRO, Highett, VIC.

Leal, W.S. & Mochizuki, F. (1990). Chemoreception in astigmatid mites. Naturwissenschaften 77: 593-594.
Woolley, T. (1988). Acarology: Mites and Human Welfare. Wiley, New York.