Smelly, slimy and slithering

We have a wildlife-friendly garden, and part of that is a pesticide-free compost heap. When it needs to be turned over, the usual creatures are plentiful - earthworms, slugs, woodlice and so on - but sometimes something less familiar appears, brought to me by my loving wife...

A mass of about 20 worm-like creatures attached to a decaying slug.

I usually deal with invertebrates with legs, but I like a challenge so, holding my nose (the slug-remains were highly fragrant!) looked more closely.

One of the 'worms' off exploring.

It was clear very quickly that these weren't leeches. Although they moved like them, they didn't have the segmentation or mouthparts - instead they were a type of flatworm. A quick look at Jones (2005) told me they were Kontikia ventrolineata, an Australian species introduced through the ornamental plant trade.

Kontikia ventrolineata - the pair of grey lines on the dorsal surface is a key identification feature.

Kontikia ventrolineata - the series of light and dark bands on the ventral surface is another key identification feature, and give it its specific name.

The garden plant trade has introduced several Australasian flatworms to Britain,and some such as the Australian flatworm Australoplana sanguinea and the New Zealand flatworm Arthurdendyus triangulatus can be problematic as they are predatory and hunt earthworms, and may impact on populations of our native species which are so important for soil quality. Fortunately K. ventrolineata is probably less troublesome as it feeds on small snails and possibly slugs, as well as (in this case) scavenging. As yet, I am unaware if it has an impact on our native molluscs, though it is widespread in southern and southwestern England (and as I understand it has been found as far north as Scotland, although the NBN currently holds no records). So, observations and data are always welcome, and if you see this species in England or Wales, let Hugh Jones know via the Natural History Museum in London (scroll down, he's a Scientific Associate), or in Scotland, you'll want Brian Boag who works on introduced and invasive species.

Reference

Jones, H.D. (2005). Identification: British land flatworms. British Wildlife 16(3): 189-194.

Beetles love big butts and they cannot lie

Spring means many things - for many species overwintering adults re-emerge and set about the important business of reproduction. One common species that is often seen doing this is the green dock beetle Gastrophysa viridula. It feeds mainly on broad-leaved dock Rumex obtusifolius and related species and in April/May patches of dock can be seen with large numbers of these beetles. Such groups can be highly localised however - one patch of dock can have hundreds of beetles while a nearby patch on the same site seems to have none, possibly due to adults clustering for mate-finding purposes - it is not due to mobility as they can fly. Mating is a competitive activity though as males may try to dislodge rivals, and have foot-pads. These appear white around the sides of the tarsi (feet) to help them grip the female.

Two male G. viridula compete for one female.

Gastrophysa viridula as they are often found - a mating pair.

A dislodged male G. viridula draws its legs in for protection.

The females are particularly distinctive as they have swollen abdomens which extend beyong the elytra (wing cases). There are two or more generations per year (possibly up to six depending on temperature and other conditions) and the oval yellowish eggs can be seen in small clusters. The first new adults emerge in June and others appear through to September. They then overwinter from October to April.

Eggs of G. viridula.

Female G. viridula showing the swollen black abdomen.

The adults chew roundish holes in dock leaves, but the black larvae can skeletonise whole leaves until just a network of veins is left. For this reason, where certain Rumex species are considered invasive, G. viridula has been suggested as a potential biological control, though as ever introducing non-native species needs to be considered very carefully to avoid unwanted impacts on native species.

G. viridula larvae feeding on dock leaf.

It's OK to be takeyai

It's time to look at a family of insects I've not written about before - the Tingidae or 'lacebugs'. These are true bugs (Hemiptera) and, though small, are distinctive due to having a lace-like network of reticulation covering the pronotum and forewings. The function of this isn't immediately obvious, but as they often look like dried seeds or similar, it may be a form of camouflage. They are also flattened dorso-ventrally, with the head, in many species, hidden beneath a hood-like or bulging extension of the pronotum. Although generally unfamiliar to non-entomologists, they can be quite common and there are over 2,000 known species worldwide (25 in the UK, 8 of which are listed as scarce or rare).

All Tingidae are plant-feeders, and being mostly host-specific, some are considered pests. One of these, a Japanese species first recorded in Britain in 1998 (Halstead & Malumphy, 2003) was found in our garden yesterday - the andromeda lacebug Stephanitis takeyai. It feeds on the 'Japanese andromeda' Pieris japonica and has been introduced into the USA and Europe via the ornamental/garden plant trade. It also uses other Pieris species, as well as rhododendrons and azaleas - as such it is sometimes considered a pest in ornamental gardens, though in ours it is welcome to eat what it can find as we don't grow these!

Stephanitis takeyai, approx 4mm long (excluding appendages)

The dark reticulation is clearly visible here and, along with the dark wing markings (which break up the outline) and leaf-coloured legs/antennae I suspect provides effective camouflage. The bulbous hood of the pronotum is visible, almost entirely obscuring the head/eyes, but can been seen more clearly from different angles.

Stephanitis takeyai, side view showing the pronotal hood and, just behind it a thin longitudinal pronotal keel. The flattening of the body is also clear.

Stephanitis takeyai, front view, again showing the pronotal hood.

Although some North American tree-pest species have been well studied, there is a lack of information about the Tingidae in more general sources. There is a short section including keys in Southwood & Leston (1959) and although Ryan (2012) updated the list in this publication, adding S. takeyai and Corythucha ciliata, identification details were not included. However, S. takeyai is a distinctive species, only likely to be confused with another rhododendron-feeding introduction, S. rhododendri which is broadly similar, but has mainly pale wings with a brown band near the base.

S. rhododendri is covered briefly in Becker (1974), Buczacki & Harris (1981) and similar publications, as well as in Southwood & Leston (1959), while Alford (2011) covers the platanus lacebug C. ciliata, a North American pest of various plane trees first found in Britain in 2006, again via the plant trade. However, there is much to learn about these insects, and it seems likely that more will be accidentally imported, so definitely a group worth keeping an eye out for, including on garden/ornamental plants.

References
 
Alford, D.V. (2011). Plant Pests. Collins, London.
Becker, P. (1974). Pests of Ornamental Plants. HMSO, London.
Buczacki, S. & Harris, K. (1981). Guide to the Pests, Diseases and Disorders of Garden Plants. Collins, London.
Halstead, A.J. & Malumphy, C.P. (2003). Outbreak in Britain of Stephanitis takeyai Drake & Mao (Hemiptera: Tingidae), a pest of Pieris japonica. British Journal of Entomology & Natural History 16: 3-6.
Ryan, R. (2012). An addendum to Southwood & Leston's Land and Water Bugs of the British Isles. British Journal of Entomology & Natural History 25: 205-215.
Southwood, T.R.E. & Leston, D. (1959). Land & Water Bugs of the British Isles. Warne, London. [there is a 2005 reprint which is much cheaper, and a CD-ROM version from Pisces Conservation Ltd.]

Leaf beetle key - write, edit, plug

If you are a regular here, you'll know that I have a considerable interest in invertebrates and that they form a large proportion of the topics I write about (a glance at the 'tag cloud' in the right margin will confirm that). However, you might not know that I specialise a little more than that and that one of my areas of specialism is in the Chrysomelidae - the 'leaf beetles', which include the 'seed', 'reed', 'flea' and 'tortoise' beetles - and the two small closely related families, the Orsodacnidae and Megalopodidae. You may be familiar with these groups having a slightly different taxonomic arrangement, such as the Bruchinae being accorded full family status, but recent cladistic work (e.g. Reid, 1995) suggests otherwise.

A few years ago I became interested in this group as a voluntary species recorder for the UK's Biological Records Centre (BRC), and later as organiser of the related UK Recording Scheme. I soon found that, even with the excellent Atlas to British and Irish species having been published (Cox, 2007), I needed to collect a large number of individual journal articles in order to be able to reliably identify adults of the British chrysomelid fauna and that even then there were gaps. The last key covering all species was Joy (1932) which, although excellent, was unavoidably out of date (and hard to find affordably until the CD-ROM version appeared), while the update (Hodge & Jones 1995) was out of print. Grr. Although the BRC were extremely helpful, sending me copies of the articles I needed if they had access to them, it became clear that a lack of readily available user-friendly identification literature was a major barrier to expanding interest in this beetle group. Such a barrier needed to be overcome, especially as the Chrysomelidae includes many charismatic (shiny, colourful and metallic such as the green dock-beetle Gastrophysa viridula) species as well as a number of considerable economic importance (horticultural and agricultural pests) such as the unpopular Lily Beetle (Lilioceris lilii) and the notorious potato pest, the Colorado Beetle (Leptinotarsa decemlineata) although the latter is currently unable to colonise Britain due to low winter temperatures. There is also a conservation component as accurate identification is needed to provide useful distribution and monitoring data. For example, there are a number Biodiversity Action Plan (BAP) and Red Data Book (RDB) species, such as the Pashford Pot Beetle Cryptocephalus exiguus which provides an (unfortunately) excellent case study of ineffective landscape-scale conservation, while the flea beetle Psylliodes luridipennis is a UK endemic known only from Lundy Island where it is threatened by over-grazing and invasive rhododendron.

Consequently, I made the decision that 'the book' would only appear if I wrote it, and so I began, aiming for an intermediate audience as I wanted to cover all British and Irish species, and many require dissection under a low-power microscope - not something for beginners maybe... I won't go into too much detail other than to say it was difficult - really, really difficult. The initial draft wasn't too bad to write, but - as expected - had many errors and omissions which were discovered during testing. However, many testers provided excellent tips and suggested changes - some extensive - which greatly improved the final version. The difficulty came where species were not covered reliably by existing literature, and this happened a lot while trying to write keys for the notoriously tricky flea beetle genera such as Longitarsus. I was aided in many cases by the excellent images (including genitalia) on the European Chrysomelidae website, but in the end there is no substitute for going to a museum or other institution, and consulting specimens in their reference collections such as those held in Winchester (Hampshire County Council), Oxford (Oxford Uni Museum of Natural History) and at the BENHS HQ near Reading. This is what sampling and collecting is for - it ain't decoration or 'train-spotting'!

A tray of beetles from the Oxford Uni MNH collections

So, after editing, re-editing, adding a few species that had been newly found in Britain, and making changes following taxonomic updates, the final version - complete with cover photo - went off to the publisher and then the printer. I was expecting it to be ready in mid to late November, but - much excitement - a courier delivered a box of my author's copies this morning - whoop! I think they are great (obviously) and a bargain at only £8.50 - available here - enjoy! All the many many hours of beetle-scrutiny was worth it - now, I seem to remember there's no general textbook covering this family...

Woo hoo! A box of brand new copies of my key to British and Irish leaf beetles.

References

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

Hodge, P.J. & Jones, R.A. (1995). New British Beetles: Species not in Joy's Practical Handbook. BENHS, Reading.

Joy, N.H. (1932). A Practical Handbook of British Beetles (2 vols., 1976 reprint). Classey, Faringdon.

Reid, C.A.M. (1995). A cladistic analysis of subfamilial relationships in the Chrysomelidae sensu lato (Chrysomeloidea). In: J. Pakaluk & S.A. Ślipiński (eds.) Biology, Phylogeny, and Classification of Coleoptera: Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum i Instytut Zoologii PAN, Warsaw, pp. 559-631.

Why Smurfs are like slipper limpets

Yes, I do mean Smurfs, those little blue Belgian cartoon characters... and slipper limpets are marine gastropods, Crepidula fornicata. So, why are they similar? Well, you probably know that, although there are lots of Smurfs (101 in fact), only one is female - Smurfette. Now, this could easily lead into pornographic territory (and undoubtedly has, somewhere on the Internet), but that's not what the Ecology Spot is about... instead I want to be a bit speculative and look at how this might affect Smurfs biologically if they were real...

One possibility would be that they became eusocial (like ants, bees and termites for example), with Smurfette as the only reproductive female (I assume Smurfs are viviparous, but maybe there are Smurf eggs - who knows?). However, Smurfette does not appear to be a large sedentary egg-layer (or large sedentary birther-of-live-young Smurflings), nor do there appear to be non-reproductive females rendered infertile by Smurfette pheromones. This is the case in, for example, the honey bee Apis mellifera, where the queen emits Queen Mandibular Pheromone (QMP), a pheromone set which, among other functions, inhibits ovary development in other females. So, the queen bee remains on the throne, and the princesses have to wait in line.With no other females present, and Smurfette running around actively, this seems unlikely. Instead, I think Smurfs might be an example of sequential hermaphroditism (SH).

One of the best-known examples of SH is C. fornicata. Though native to the eastern coast of North America, it has been widely introduced into the coastal waters of Europe, Japan and the NW Pacific, where it is invasive (having no predators away from its original range), competing with native filter-feeders for food. For more on its British history see here.

A stack of C. fornicata (plus a small chiton on the left) - photo by F. Lamiot, and used here under the Creative Commons Attribution-Share Alike 1.0 Generic license.

They can often be found in stacks and chains, their SH reproductive strategy meaning that the largest, oldest individuals, found at the base of  the stack are female, while the younger, smaller ones at the top are male, and some in between are 'transient'. If the female(s) die, the largest male becomes a new female.

Proestou (2005) showed that C. fornicata tended towards a 1:1 sex ratio, and that as a male's distance from a female increased, his reproductive success decreased i.e. that the males closest to the female have a competitive advantage. From this, it follows that if these males suffer a reduction in reproductive success (e.g. from competition with other males) that is greater than that due toswitching sex at a small size, then they should change. Only the lowest male in a stack can change sex, a process that takes around 60 days, during which the penis regresses and the pouches and glands of the female duct develop. If a juvenile settles on an existing stack, it develops as a male and may stay like this for up to 6 years due to pheromones released by females at the base of the stack (Fretter & Graham, 1981). Presumably the death of a female means this pheromone ceases to be produced and thus the male can change sex - another process must prevent others from changing, possibly pheromones from the new female-to-be? As there are 'transients' which complicate the picture, a pheromone gradient seems plausible.

So, although the sex ratio is different in Smurfs (100:1 rather than 1:1), an SH strategy fits well. If Smurfette dies, then as the oldest male, Papa Smurf should become Mama Smurf, with some of the others (who after all, could be 'transient' and we wouldn't know by looking at them) waiting in line.

Next post - normal service will resume!



References

Fretter, V. & Graham, A. (1981). The Prosobranch Molluscs of Britain and Denmark. Part 6. Journal of Molluscan Studies Supplement 9: 309-313.
Proestou, D.A. (2005). Sex change in Crepidula fornicata: Influence of environmental factors on reproductive success and the timing of sex change. Dissertation, University of Rhode Island.

The Bluebells and the Town-hall Clock

In most of Britain, bluebells (Hyacanthoides non-scripta) are a familiar sight in the spring - a few here and there in hedgerows, grassland and on western sea cliffs, but if you visit ancient woodlands, you have a good chance of seeing carpets of these flowers...

Bluebell Wood in the Holywell Estate in Hampshire

Bluebell flowers are all on one side of the stem forming a 'raceme' of drooping flowers, each a cylindrical bell shape with two blue bracts at the base, the petals (more technically 'perianth segments' as they are fused) curled back strongly at the tips, and the anthers cream-coloured. However, you might see some that aren't quite like this - either the introduced Spanish Bluebell (H.hispanica) or, more commonly, the hybrid between the two, H. x massartiana, both being garden escapes.

H. hispanica looks superficially similar to the native bluebell, but the flowers are not all on the same side of the stem, and are not all drooping, the tips are flared outwards but not tightly curled back, and the anthers are blue. The hybrid is sometimes confused with this species, but has features intermediate between the two such as flowers that curl slightly back at the tips.

If you do visit an ancient bluebell wood, however, don't forget to look around for other species - bluebell carpets are an impressive wildlife spectacle, but this type of habitat supports many other species, some of which may be less familiar, such as Moschatel (Adoxa moschatellina), also known as 'Town-hall Clock'.

The pale green  trifoliate leaves of Moschatel

The tiny pale greenish flowers of Moschatel

Moschatel, named after its musky smell, is common in some places, particularly ancient woodlands on damp, fertile soils (and sometimes mountain ledges - in southern Europe, it is a mountain species), but is often overlooked. The trifoliate (three-part, like clovers) leaves are fairly easy to spot, each of the three leaflets further split into three lobes, but the tiny flowers can be elusive. There are five flowers at the end of each long stalk and these are arranged as a cube; four facing sideways at right-angles to each other, the fifth pointing straight up. This gives the plant its alternative 'town-hall clock' name as it recalls the shape of old clock towers with four faces and a roof on top. However, if you want to see it, you have to be quick - it soon dies back and for much of the year there is little evidence of it above ground.


There are many other ancient woodland indicators that can be found by visiting the right sites in spring - as I write, some are still visible, but soon the summer species will take over for another year...

A bluebell wood from ground level

Focusing on the familiar II: ladybirds Part 2

Following on from my introduction to 7-spot and harlequin ladybirds, in part 2 I want to look at some other common British species. The next most familiar is probably the 2-spot ladybird which has two common patterns which look like they could be separate species - either red with 2 black spots or (despite the common name) black with 4 or 6 red spots. The 2-spotted form has large white side-spots on the pronotum (a bit like 7-spots and harlequins and this can look like a black M/W mark) but the others have a more or less black pronotum. In all forms, the legs are black. The 2-spot is found on a wide range of plants in many habitats, and is common as a species that over-winters in buildings.

The two common colour forms of the 2-spot ladybird mating on a reedmace

Another common species is the 24-spot which is a rusty orange-red colour with black spots. The exact number of spots varies (from 0 to 24, with 20 being a common number), and they can be fused - there are also darker forms but they are not as common as in the 2-spot. The elytra also have tiny hairs which are visible with a hand lens (and can just be seen in the photo below). This is found in grasslands where it eats leaves and is commonest in the south of Britain.

24-spot ladybird found in loose soil on an ant-nest

Keeping with the black-on-red species, the 11-spot is widespread and common on various plants on dunes and in other habitats. As is often the case with ladybirds, the number of spots varies (from 7 to 11, although 11 is most common) and the pronotum is black with white sides.

11-spot ladybird escaping digging of soil

Superficially similar to the 11-spot, Adonis' ladybird is less common with a more scattered and localised distribution, although it has been spreading recently. It is red with 3-15 black spots (often around 7) and the pronotum is black with variable, but generally more extensive, white edges and marks than the 11-spot (in the photo below you can see that the front edge of the pronotum is white).

Adonis' ladybird on plastic on a farm

Lastly, the kidney-spot ladybird which is scattered but can be locally common, is black with 2 large orange or red spots. It is associated with various deciduous trees, especially willows, poplars, ash and birch, and is usually found at or near the base rather than higher up. The description may sound similar to the dark form of the 2-spot, but these have 4 or 6 red spots whereas kidney-spots have two red spots - this is why scientific names are so useful - common ones can be misleading. Also, the kidney-spot is much rounder when viewed from above and has splayed edges making it look almost tortoise-shaped. In the photo below you can see a yellow fungus growing on the rear of the elytra - if you want to know more about what this turned out to be, have a look here - it was quite surprising.

Kidney-spot ladybird - note the yellow fungus growing at the rear

So, that is 5 more ladybirds covered - don't forget that there are also the yellow-and-black species (they may form the subject of a separate post), plus some striped ones, some rareties and the micro-ladybirds. If this is a subject that interests you, there is a UK Ladybird Survey for all abilities where you can send in records of your sightings which all helps understanding the dynamics and ecology of one of our most popular groups of insects.

Further reading

Majerus, M. & Kearns, P. (1989). Ladybirds. Richmond, Slough. An excellent little book with detailed keys to species, including the 'micros' - a new edition is being prepared.

Majerus, M., Roy, H., Brown, P. & Ware, R. (2006). Guide to Ladybirds of the British Isles. FSC, Preston Montford. A fold-out laminated sheet perfect for beginners.

Roy, H., Brown, P., Frost, R. & Poland, R. (2011). Ladybirds (Coccinellidae) of Britain and Ireland. FSC, Shrewsbury. Details of all species including maps, identification features, ecology and so on.

Common and scientific names of species mentioned here

7-spot: Coccinella septempunctata

Harlequin: Harmonia axyridis

2-spot: Adalia bipunctata

24-spot: Subcoccinella 24-punctata

11-spot: Coccinella 11-punctata

Adonis: Hippodamia variegata

Kidney-spot: Chilocorus renipustulatus

Focusing on the familiar I: ladybirds Part 1

A few days ago, I asked a question on my Ecology Spot facebook page i.e. whether anyone had any requests for topics they'd like to see. The first one was to cover aspects of identification of more familiar species for non-specialists. This is a slight departure as I often look at the fine 'taxonomic morphology' of more obscure (even if not uncommon) species, but it's a good idea so here goes with the first of what I hope will be an ongoing series, Part 1 of a beginners' guide to ladybirds (or ladybugs if you prefer).

Ladybirds are beetles of the family Coccinellidae, and are often split into the larger and more familar 'macro' ladybirds and the smaller microladybirds or 'inconspicuous' ladybirds. In Britain there are 47 species in total and 26 are the more typical species that I want to look at here (well, a few of them at least). The most familiar is probably the 7-spot ladybird which is large (for a ladybird) and has (on its elytra or 'wing cases') the typical pattern of black spots on a red background. However...

Teneral (recently emerged) specimen of the 7-spot ladybird

This is a 7-spot but is yellowish rather than red as it is a newly emerged adult and its pattern has yet to develop. In fact it you looked even earlier, you'd see this:

A 7-spot ladybird just having emerged from its pupal skin

The reason for showing these pictures, apart from being a reminder that even common things can be tricky, is to show two key features of the 7-spot:

• Black legs.
• Black pronotum (the plate between the head and wing cases) with white spots to the sides.

Features like this are important as they help distinguish species from each other even when the spot pattern is abnormal (which does happen - spots can be fused, increased in number or missing). There is a Scarce 7-spot which is very similar but has two pairs of tiny white triangles underneath (by the hind and middle legs) while the 7-spot has a single pair (by the middle legs).More commonly however, the 7-spot needs to be distinguished from the Harlequin ladybird.

Harlequin ladybird

The Harlequin is well-known as an invasive non-native species that has spread rapidly across Britain since its arrival from Asia in 2003. It is often found hibernating in buildings and evidence has started to be found of its impact on native species such as the 2-spot, through competition for food and by direct predation of eggs and larvae. The Harlequin is highly variable (see here for the range of patterns) though the one above is commonly seen. You can see that the legs are paler than those of the 7-spot, and the pronotum is more extensively white with a black M (or W) shaped mark. Easy!

That's all I want to cover for now - more coming soon. If this is a subject that interests you, there is a UK Ladybird Survey for all abilities where you can send in records of your sightings which all helps understanding the dynamics and ecology of one of our most popular groups of insects.

Further reading

Majerus, M. & Kearns, P. (1989). Ladybirds. Richmond, Slough. An excellent little book with detailed keys to species, including the 'micros' - a new edition is being prepared.

Majerus, M., Roy, H., Brown, P. & Ware, R. (2006). Guide to Ladybirds of the British Isles. FSC, Preston Montford. A fold-out laminated sheet perfect for beginners.

Roy, H., Brown, P., Frost, R. & Poland, R. (2011). Ladybirds (Coccinellidae) of Britain and Ireland. FSC, Shrewsbury. Details of all species including maps, identification features, ecology and so on.

Common and scientific names of species mentioned here

7-spot: Coccinella septempunctata

Scarce 7-spot: Coccinella magnifica

Harlequin: Harmonia axyridis

2-spot: Adalia bipunctata