The Ecology Spot says 'Have a cool Yule'

Just a quick pre-Christmas message to say I hope you have a great festive season and thanks to all my readers. 'The Spot' has a growing readership which is great and has recently celebrated its 1st birthday. So, whether you like the taxonomic morphology of small beetles, occasional forays into palaeontology, or fearsome garden predators - among other topics - I hope you've enjoyed them. I'm off now for a few days - back next week.

Hungry Christmas robin - bring out yer crumbs!

What's in the box? No.10 - a tricky customer

My epic beetle identification marathon continues... in envelope number 3 (of 20+ containing chrysomelid 'flea beetle' specimens collected in the Uk during 2011), I found the following, about 3mm long and a dark metallic blue colour.

The latest beetle specimen in dorsal view.

One of the first things I noticed was the groove running along the rear edge of the pronotum.

The groove along the rear edge of the pronotum.

Many chrysomelids have a groove in this position, but it varies between genera - some are less even in depth than this one and can have short furrows running forward from the ends. Along with features such as colour and shape, this indicates that the specimen is in the genus Altica. This is always potentially difficult as reliable identification of Altica species requires dissection - in this case of a male in order to see the aedeagus (identification of females is detailed in Kangas & Rutanen, 1993). However, the curved sides make A. ericeti unlikely while the elytra are rounded at the rear but not bulbous/widened, so it is probably not A. brevicollis or A. lythri. Similarly, the lack of small dents at the tips of the elytra suggest it is not A. oleracea. This leaves three British species - A. helianthemi, palustris and carinthiaca. These do differ to some extent in terms of the fineness and depth of punctures, shininess/dullness of the top of the head, prominence of the elytral shoulders and so on, but these features are somewhat variable and comparative and so, dissection of males is, as noted above, the only way to make a definite species-level identification. Pins and forceps deployed, the aedeagus was removed.

Aedeagus (ventral view)

Aedeagus (dorsal view)

Aedeagus (lateral view)

Immediately it is clear that this is not A. helianthemi which has an aedeagus that is more clearly broadened towards the tip and S-shaped in lateral (side) view. However the aedeagi of A. palustris and A. carinthiaca are very similar and care needs to be taken. Both are more-or-less straight in lateral view, end in a small point, have transverse wrinkles and are the same overall shape. Fortunately for identification purposes, there are some small but diagnostic differences allowing them to be separated. Firstly, on the right-hand side in the lateral view above, there is a distinct dent about one third of the way down - something that, although not always this clear, is seen in A. carinthiaca but not in A. palustris. Also, although the ventral views are very similar, the arched structures near the tip in dorsal view match those of A. carinthiaca and this is indeed the species we have here.

This is an interesting find as it was only recognised as a British species in 2000 (Cox, 2000) and is found on meadow vetchling (Lathyrus pratensis) in a variety of habitats, mainly in the south and east of England, though there has been a recent (2011) record from further north in Cheshire. Since 2000, there have been numerous records of this species in the UK and, although the Cheshire record has not yet been included on the database, the distribution is shown by the NBN as follows:

Distribution map of Altica carinthiaca in Britain © National Biodiversity Network

The south-eastern distribution is clear (this specimen, from Oxfordshire, is within the usual British range) and although there is evidence of some expansion of range e.g. in Finland since the 1980s (Kangas & Rutanen, 1993), it is likely that this species has been present but overlooked in Britain for some time. Indeed, the difficulty of identification (given that even the aedeagi can be similar in some cases) has meant that it has been confused with both A. palustris and A. helianthemi, the latter when known as A. pusilla var. montana, with museum specimens at least as early as 1939 being attributable to A. carinthiaca (Cox, 2007).

So, we have a species which, although not a rarity, was overlooked until fairly recently, so records are valuable in order to provide information about its British distribution. It is also a good example of the importance of dissection in the identification of some chrysomelid species, especially the 'flea beetles' as well as showing that even once dissected out, care may be needed to accurately use sometimes subtle and variable features of structures such as the aedeagus. Now, where's that 4th envelope of beetles..?

References

Cox, M.L. (2000). Progress report on the Bruchidae/Chrysomelidae recording scheme. The Coleopterist 9(2): 65-74.

Cox, M.L. (2007). Atlas of the Seed and Leaf Beetles of Britain and Ireland. Pisces, Newbury.

Kangas, E. & Rutanen, I. (1993). Identification of the females of the Finnish species of Altica Müller (Coleoptera, Chrysomelidae). Entomologica Fennica 31(4): 115-129.

Egrets, I've had a few, but then again...

OK, yes, the title is a terrible Piaf pun (je n'aigrette rien?) - maybe I'm feeling festive and frivolous... Anyhow, I've posted a lot of invertebrate taxonomic morphology lately, especially that of small beetles, so I thought I'd move up the size scale to look at a species that is probably one of Britain's most popular birds, the Little Egret (Egretta garzetta).

A little egret stalking through the water of a coastal scrape/lagoon

This is a small heron and its white plumage makes it both attractive and easily recognisable - the size and black beak separate it from other, scarcer, egrets in Britain. Although familiar to many people, its current British population size, around 1,600 wintering birds and 150 breeding pairs (RSPB, 2011) is a fairly recent phenomenon. Until the late 1980s, it was only seen occasionally, not breeding in Britain until 1996. This was  a result of natural colonisation from France where, in previous decades, it had expanded from southern Europe into western and northern France following effective legal protection which allowed its population to recover after massive declines up to the 19th century as birds were killed to provide decorative hat-feathers. In fact, the decline of this species was one of the reason the RSPB was founded back in 1889. It is now seen regularly, especially along the south coast, and in East Anglia and Wales, but is included on the Amber List as a rare breeding species as the number of breeding pairs remains fairly small.

It feeds on fish and other small animals (insects, amphibians, reptiles, crustaceans) which it hunts mainly by stalking in shallow water, sometimes also running with raised wings or shuffling its feet to disturb small fish; at other times they may simply stand still and ambush their prey. While bird-watching yesterday, I was pleased to see a little egret using the foot-shuffling method (which the other British egrets do not use) and, although I'm no wildlife film-maker, I did manage to capture this footage (on a compact, hence the graininess, but the behaviour is still visible):



You can see the shuffling, sometimes circular foot movements which, at the end, result in the rapid (blink and you'll miss it) capture of a prey item. I hope you enjoyed reading this tale of conservation success - also a departure from the usual invertebrate theme - more coming soon.

Prey detected, the beak strikes!

Reference

RSPB (2011). Little egret. [accessed 16/12/2011]

What's in the box? No.9 - groovy beetles

If you've been here before, you'll be used to my ongoing series about the identification of beetles that are sent to me my post. If, not here's a recent (and rather pretty) example to get you started. So, working through the recent numerous selection I received in an old Kodak slide box, I found a pair that summed up how the flea beetles (within the Chrysomelidae) are often perceived - small and sort of brownish...

A pair of flea beetles - even if you are new to this group, it's easy to see that the one on the left is male...

The presence of an exposed aedeagus (not usually seen without dissection) helpfully shows the difference in size between the male on the left (4mm long without appendages) and the female (5mm). The enlarged hind femurs are visible in dorsal view and show these to be 'flea beetles'. I won't go through the full identification process, but the combination of (1) hairless elytra (wing cases), (2) a strong unbroken groove at the rear of the pronotum (with foward-pointing ends), (3) bulges above the antennal bases being separated from the top of the head by a weak groove, (4) overall colour and (5) the top of the head without coarse/dense punctures show that it is in the genus Neocrepidodera.

Pronotum with a clear, broad groove along the rear edge with thin forward-pointing ends. The shallow, fairly sparse punctures and splayed edge can also be seen.

There are only three species within this genus in Britain. One, N. ferruginea, does not have the forward-pointing ends to the pronotal groove, which leaves us with N. impressa and N. transversa. Although very similar, N. impressa is found in coastal habitats such as saltmarshes and dunes unlike these specimens which were found inland. So, N. transversa is likely, but needs to be checked using the aedeagus - in this case easily visible.

Dorsal view of the aedeagus

Ventral view of the aedeagus

In this case, the identification is straightfoward - the tip of the aedeagus is spear-shaped, a characteristic of N. transversa, while in N. impressa it would be broadened and leaf-shaped (an example can be seen here, though note that the genus is given as Asiorestia as there is some taxonomic disagreement between British and continental authors). So, we have N. transversa, a widespread species found on a range of plants in various habitats (so, location may not help that much), but it is a nice easy example of the use of the aedeagus to separate closely related species. More small beetles coming soon...

I went on holiday and found an alien!

Every now and again, me, my wife, and some friends go for a short holiday on the Isle of Wight (it's not far away and there's a house we can borrow for free!). Last time, we found a fossil crocodile - this time a small alien appeared inside on one of the windowsills...

Dorsal view of the insect which is 18mm long 'nose to tail'.

As it happens, it was already dead when found, but well preserved, just missing a front leg. This made it particularly obliging and easy to photograph. It's also a distinctive species in the UK and is an adult Western Conifer Seed Bug Leptoglossus occidentalis (note the white zigzag mark across the middle of the wings), a true bug (Hemiptera) in the family Coreidae (squashbugs). A native of North America, it was first found in Britain in 2007 when a single specimen appeared in a college in Dorset, southern England. Since then, there have been numerous sightings all over the country, though most commonly along the south coast, suggesting migration across the English Channel following its introduction to continental Europe (northern Italy) in 1999, after which it spread widely and rapidly. Nymphs have also been found in Britain, indicating at least one breeding population and adults have been known to enter buildings to hibernate (possibly the source of this specimen); adults fly well, making a buzzing sound - being relatively large (but harmless to humans), this means they are often easy to detect if they enter houses.

As the common name suggests, it is associated with conifers and feeds on the cones and seeds of over 40 species, particularly trees in the family Pinaceae. In North America, it can be a serious economic pest of conifer nurseries (e.g. causing a large proportion of conelets to abort) but in Europe it is generally found in gardens and parks so such impacts have not been seen, and future effects are uncertain - nor does it attack timber. So, let's have a look at our little alien in more detail.

Close-up of the head and pronotum (the 'head cone' is about 3mm long).

Here it is clear that the reddish pronotum has a detailed pattern of yellow blotches containing tiny black spots, while the head is dark with a central red stripe and other smaller red marks. Also, the antennae which appear smooth at a distance are actually densely covered in short bristles.

Dorsal view of the wings.

Here, the distinctive zigzag markings on the forewings are clearly visible, as is the venation of the membranous hindwings, the covering of short bristles, and the black-and-white markings on the edge of the abdomen ('connexivium').

Ventral view of the head and thorax showing the pointed mouthparts (rostrum).

The long rostrum is clearly visible here and is jointed with the section lying underneath the head having fine transverse lines (striations). The rostrum is formed from mouthparts modified to peirce and feed on plant tissues and is attached to the front of the head (in other suborders of Hemiptera, the attachment might be further back). You can also see where the front right leg was attached - now missing, there is a green blob where the point of attachment sealed over.

A close-up of the hind leg.

Lastly, the hind leg provides another distinctive feature (along with the reddish colour and pale zigzags) allowing this species to be easily identified. The inner edge of the hind femur is armed with sharp teeth, but the key feature is the flattened leaf-like shape of the hind tibia which can be seen clearly here along with the tiny black dots puncturing it. Again, although the legs look smooth at a distance, they actually have dense tufts of hairs.


So, although this species has only been in Britain for a few years, it appears to be spreading rapidly and as it is so distinctive, you have a fair chance of seeing one (possibly in your house), especially in the south. For more info on it, I recommend the excellent British Bugs page which includes links to a life stages chart and a more detailed factsheet (which provided some of the info here) as well as the recording scheme for sightings of this species in the UK.

Circus of the Spineless #68 - gifts galore!

It's December, so it's tempting to come up with a festive theme for this edition of Circus of the Spineless. However, I'm going for a 'birthday' theme instead because it's my blog's 'official' 1st birthday - 'official' (like the Queen's) because it's about a year since it really got going though I started it a bit before that. And, my 20,000th pageview just appeared, so thanks to whoever that was! Anyhow, I digress - please do click to take a giftbox, a slice of virtual cake and/or a glass of whatever suits you...

First up, Susannah of Wanderin' Weeta fame has provided some gift-wrapped goodies found tucked away in a vacant lot ('brownfield site' in UK-speak!) which goes to show it's always worth a look. To celebrate, why not start with a slice of tasty cake...

Next, a pair of splendid parcels arrived from John at 'Carp Without Cars' - the first arrived as 'snail mail' but not really (you'll see what I mean, just drink from the glass of finest red) and the second comes in a smaller package that rarely displays its contents quite as clearly as this...

My birthday cup already runneth over, but there's more to come... Here, Daniel at 'Notes from Dreamworlds' takes a close, close look at some freshwater critters courtesy of some high-quality optics (feel free to contrast this with the microscopy efforts on my blog!) and wraps the whole thing up as an 8-minute video - a veritable treasure-chest of precious things.

And lastly, I shall give myself a small gift of shameless self-promotion... Here, I look at the shiny jewelled contents of a box that really did turn up in the mail, so why not sit back with an ice-cold beer - mmm.... foamy...

So, that's all from my birthday-themed CoS #68 - thanks for coming along to the party; the more the merrier and there's no-one on the door to check for invitations. Next month, prepare yourself for some myrmecology as CoS scuttles off to Wild About Ants. Byeeee.

What's in the box? No.8 - shiny shiny jewels

In my previous article about beetles-by-post, I mentioned that I would soon get onto the reed beetles (family Chrysomelidae; subfamily Donaciinae) that I found in the first batch I looked at. Always one to keep my promises, here is the first one presented in all its bright and bejewelled glory...

The first of the two reed beetles; note the bright green elytra and pronotum and the long back legs.

This specimen is about 8mm long, not including appendages, and even at this magnification the rows of punctures on the elytra are obvious, as are the wrinkles on the pronotum. However, lets look at some closer detail - after all, the reed beetles look as if they should be easy to identify (they are brightly coloured and reasonably large), but species can in fact be quite difficult to separate as the colours are variable as are some other features such as spines on the legs.

A closer look - see the dents on the side of the pronotum and the pattern of wrinkles with a longitudinal marks down the middle. You can also see that the elytra are hairless.

A close-up of the head; this may not be needed for identification, but the fine detail is fascinating, including the sculpturing (a central groove matches the one on the pronotum), prominent eyes and tiny hairs.

Even closer still; looking at the fine detail of the elytra, you can see the punctures clearly and on the surfaces between them some fine 'microsculpturation' i.e. the surface looks shiny but isn't completely smooth.

Some of these features such as the pronotal wrinkles and the precise form of the central pronotal groove (e.g. whether it is complete or broken) are used in identification, but some essential features mean turning the beetle over.

Ventral (underside) view; the key structure here is the hind leg. Note the reddish colour at its base (the rest of the femur is dark) and the blunt tooth near the 'knee' joint with the tibia. The extent of red colour (if any) and the number/shape of hind tibial spines can be important features for identifying reed beetle species, not forgetting that some features (such as the spines) may vary between males and females - males have two femoral teeth, females have one as here although this is sometimes missing.

Zooming in on the hind tibia, a series of tiny teeth are visible on the ventral ridge.

This combination of features means this is a female Donacia versicolorea. This species is found distributed locally across Britain and is a good example of a variably coloured species - it can be darkly coloured or bronze. Adults are usually found in July and August, though this one was collected on 23rd June 2011, a little earlier than usual, though this year did have an early spring. The details above separate it from the similar D. crassipes which is larger (9-11mm) and has a pronotum that is microsculptured but not strongly wrinkled as here. D. dentata shares many features as well, but has dull elytra and two femoral teeth in both sexes.

If you are interested in British reed beetles, Menzies & Cox (1996) is excellent (and available as an unbound reprint for a few pounds) and will form the basis for the Donaciinae section of my forthcoming key to British chrysomelids. It also provides keys to separate the different genera (Donacia, Plateumaris, Macroplea), something I will cover in a subsequent article.


Reference

Menzies, I.S. & Cox, M.L. (1996). Notes on the natural history, distribution and identification of British reed beetles. British Journal of Entomology and Natural History 9: 137-162 + 2 pp. of colour plates.