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.

Highlights of 2013

December's been a quiet month on the blogging front - a large beetle project is ongoing (status review of the UK Chrysomelidae) and then of course the whole festive-season-thing. However, there was a proper summer this year with an extended period of hot dry weather extending into a mild autumn, and this meant some fine invertebrate (and other) sightings after some truly awful, cool, wet summers. The most spectacular (for me as they were all personal firsts) were probably three Lepidoptera finds between July and September - two butterflies, a monarch (Danaus plexippus) and long-tailed blue (Lampides boeticus) and a moth, the Clifden nonpareil (Catocala fraxini). The monarch is a North American species, and although some have been known to cross the Atlantic, it is more likely that this (and one from a nearby friend's garden) had escaped from a butterfly farm, maybe on the Isle of Wight. Certainly there was a small flurry of records of this species in southern England, aided by the fact that monarchs in the UK often visit gardens to seek their foodplant, milkweed (Asclepias syriaca) which is of course also non-native. The other two are scarce migrants seen in higher-than-usual numbers due to the favourable conditions this year. Being native to NE Europe, the Clifden nonpareil is more often seen on the eastern coasts of Britain, but my sighting was in Hampshire, about 10km inland where one large and unmistakable adult was seen basking on warm brickwork near scrub including its foodplants - aspens and other poplars (Populus spp.). Also a rare migrant, the long-tailed blue can be found on various Fabaceae such as everlasting-peas (Lathyrus spp.) and brooms (Cytisus spp.) - as a Mediterranean resident, it's not often seen in this country. I'll stop there, but if you'd like an affordable and user-friendly guide to European butterflies, one of my favourites is Haahtela et al. (2011). More to come from me in 2014, but until then, here are some pics from 2013...

A flock/mob of jackdaws in spring, as seen from my study window.

Adult female smooth newt in our garden pond.

A leaf beetle larva and its defensive shield of faeces and shed skins.

And finally, just to prove that I do go out and do ecology in the field, here I am taking great created newt eDNA samples at Claylands Nature Reserve, Hampshire.

Reference

Haahtela, T., Saarinen, K., Ojalainen, P. & Aarnio, H. (2011). Butterflies of Britain and Europe: A Photographic Guide. A & C Black, London.

The spider with emerald jaws

As well as mystery cocoons, breaking up some old fence panels for firewood dislodged numerous scuttling invertebrates. Plenty of woodlice, barklice and so on, and many small spiders, but also a splendid specimen of Segestria florentina. This is the largest species of the familt Segestriidae in Europe, with females reaching up to 22mm in length (excluding legs and other appendages). The family is distinguished by having 6 eyes arranged in a semi-circle (most spiders have 8) and the first three pairs of legs directed forwards (most have the first two forwards and the other two backwards). Although this species can bite (it's apparently painful, a bit like a bee sting or sharp jab with a pin, but not dangerous to humans), when disturbed, they curl up or flee to find a crevice to hide in - being nocturnal hunters using tunnel-webs with radiating threads. First found in Britain in the 19th century, this is a circum-Mediterranean/continental species that most likely arrived with ships to ports in southern England and has since spread slowly northwards - a likely candidate to increase its range as mean temperatures rise with climate change.

A large female Segestria florentina, characteristically curled up when disturbed during daylight.

This photo shows the first three pairs of legs pointing forwards very clearly. They are generally a fairly uniform black in colour with some faint paler marks such as the median line seen here, although this has been enhanced by the camera flash - to the eye, this was a very dark spider. However, the chelicerae (jaws, bearing the fangs) are an iridescent green. She needed a little gentle persuasion to show these, then was allowed to scuttle away under the shed - we do after all run a spider-friendly household...

The iridescent green chelicerae of S. florentina - the arrangement of eyes is also just about visible. Note that I am not testing her ability to bite.

The (not really) attack of the (not actually) killer spiders!

Over the last few weeks, there has been a flurry of lurid headlines about 'killer spiders' and bites leading to horrible consequences, for example this one which was actually due to a streptococcal infection rather than spider venom - and of course infections can get into any skin puncture, but the tabloid fervour doesn't bother to mention this. In reality the spiders are the false widow Steatoda nobilis which bites few people - the species is not aggressive and there are no confirmed reports of anyone being hospitalised due to the venom. There can be bite symptoms such as chest pains and tingling in the fingers but nothing like the horror-stories in some sections of the media. Sadly, the media frenzy has led to people squashing them on sight and even closing a school where they were found - a major over-reaction in my opinion due to ill-informed health & safety officials being influenced by stories of poisoning and 'infestations'. Yes, it may be Britain's most venomous spider, but there really isn't much competition for that accolade - we have nothing like the Sydney funnel-web here. As it happens, I have one living in my garden storage box, and she's really quite pretty and although she tends her spiderlings carefully is quite timid and curls up behind her web if I point the camera too close. She does not leap at me, fangs clashing and venom dripping. Then again, a headline like 'mostly harmless spider occasionally causes minor irritation' wouldn't sell many papers...

Steatoda nobilis with spiderlings in our garden storage box

Fortunately there are more reasoned sources of information such as the Natural History Museum who get a lot of calls about this spider, and some rather better reporting about why they aren't anything to be scared of after all such as here and here. Yes, they are spreading (probably due to climate change) but have been in Britain since the 19th century and have been expanding their range significantly for 15-20 years - the 'outbreak' over the last few weeks is clearly more to do with awareness with more people noticing them (and panicking) following the 'killer spider' headlines. Still, it was interesting to get an unexpected call from the Guardian yesterday wanting to interview me about the spider - I was happy to do so, and the resulting article is here. The invertebrate conservation charity Buglife has an excellent page about spider bites, including advice about what to do in the unlikely event you are bitten and develop symptoms. So, happy spidering, please don't squash them, or have nightmares about them - they'll eat plenty of your garden and household pests if you let them.

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.]

The Lawn Shrimp cometh

I quite often receive invertebrates in the post, but they are usually leaf beetles (Chrysomelidae) sent to me for identification/verification in my capacity as organiser of the UK's Chrysomelid Recording Scheme - like here for example. However, a couple of days ago I came home to find something quite different awaiting me on the doormat - a crustacean looking like a small shrimp, or to be more precise an amphipod of the family Talitridae (a group usually associated with seashore habitats rather than inland terrestrial ones).

In this case, it had already been identified as Arcitalitrus dorrieni, the 'landhopper', 'woodhopper' or 'lawn shrimp' by the finder/sender, Dennis Trunecka of the Southampton Natural History Society. This is an interesting find as it is Australian in origin (New South Wales & Southern Queensland), with the first UK record being from the Scilly Isles in 1924. Since then, it has been found in a number of sites across southern England, and also in Ireland, the Channel Isles, west Wales and western Scotland (coastal when north of southern England). However, it is not entirely clear how widely it has established itself in the last couple of decades, although individuals can move tens of metres per day as well as being moved over longer distances by the plant trade etc. (Cowling et al. 2004).

Arcitalitrus dorrieni found in woodland leaf litter in Hampshire. The seven segments of the peraeon and the three segments of the pleon are indicated. Length (head to rear of body in this curved position) approx. 6.5mm.

It is most often found under stones and dead wood or among damp material (detritus, debris, leaf litter) in gardens, damp scrub and woodland. It most likely arrived (and to some extent spread) in the UK through the transport of plants/soil to and between plant nurseries and garden centres. It is uncertain whether this non-native species has a significant ecological impact in the UK, although it is possible that it competes with (and maybe replaces) native detritivores in woodlands. In some locations, it can be found in high densities - up to approximately 2,500 per square metre in Dicksonia antartica litter on the Scilly Isles (Richardson 1980). It certainly can be a significant detritivore, consuming 24.7% of annual litter fall in a coniferous woodland in Ireland (O'Hanlon & Bolger 1999) - more than any of the native macrofaunal species.

Identification is fairly straightforward, especially given the small number of possible confusion species. Orchestia cavimana  is an introduced semi-terrestrial Mediterranean amphipod (Konopacka et al. 2009) but much paler in colour - A. dorrieni is variably dark, and orange when dead as here, though pale if preserved). However, there is another introduced terrestrial amphipod, A. sylvaticus, although this is much rarer in the UK. Using the key in Peart & Lowry (2006), the two species can be separated by looking at the epimera (the three segments of the pleon, singular 'epimeron'). In A. dorrieni, the 2nd epimeron is longer than the 3rd while in A. sylvaticus they are more-or-less equal. In the top photo, this is unclear as the rear edge of eipermon 3 is obscured by one of the legs, but with some legs (re)moved, it is clear that this is A. dorrieni. There are other features which might be required to separate further species but these do not (yet) occur in the UK, although it is possible they could be imported with plants.

A. dorrieni - from the green lines, it is clear that epimeron 2 is longer than epimeron 3.

The head bears numerous appendages including two pairs of antennae (typical of crustaceans) and a complex array of mouthparts - I won't go into the details here but there are plenty of resources online and in print providing introductions to crustacean anatomy. The lateral compression is clear (flattened side-to-side) and is generally a good way of separating amphipods from isopods (e.g. woodlice which are flattened top-to-bottom i.e. dorso-ventrally). The antennae are inserted in front of the eye which is black and not especially well developed, being covered by a transparent plate. This is likely to be an adaptation to its life within/under leaf-litter and under damp material where vision is less likely to be useful than senses such as touch - note the long antennae and various bristles.

A. dorrieni showing its lateral compression.

Head of A. dorrieni (side view)

Mouth and mouthparts of A. dorrieni (ventral view)

So, an interesting find and thanks to Dennis for passing it on to me for closer scrutiny. As ever, finds such as this are useful in determining the distribution (and in this case, spread) of species, so it is worth keeping an eye out - especially in case a third Arcitalitrus finds its way here.

References

Cowling, J.E., Spicer, J.I., Weeks, J.M. & Gaston, K.J. (2004). Current status of an amphipod invader, Arcitalitrus dorrieni (Hunt, 1925) in Britain. Journal of Natural History 38: 1665-1675. 
Konopacka, A., Grabowski, M., Bącela-Spychalska, K. & Rewicz, T. (2009). Orchestia cavimana Heller, 1865 (Amphipoda: Talitridae) enters freshwater inland habitats in the Vistula River, Poland. Aquatic Invasions 4(4): 689-691.
O'Hanlon, R.P. & Bolger, T. (1999). The importance of Arcitalitrus dorrieni (Hunt) (Crustacea: Amphipoda: Talitridae) in coniferous litter breakdown. Applied Soil Ecology 11: 29-33.
Peart, R. & Lowry, J.K. (2006). The amphipod genus Arcitalitrus (Crustacea: Amphipoda: Talitridae) of New South Wales forests, with descriptions of six new species. Records of the Australian Museum 58: 97-118.
Richardson, A.M.M. (1980). Notes on the occurrence of Talitrus dorrieni Hunt (Crustacea: Amphipoda: Talitridae) in south-west England. Journal of Natural History 14: 751-757.

What's in a wall?

As you might imagine, I don't mean bricks and mortar - instead I am more interested in the species that can be found growing on walls, particularly old rough stone walls in areas with low levels of air pollution such as might be found in the village of Slapton in south Devon. Yup, where I was one holiday a couple of weeks ago... Old walls are well known to be important for wildlife - for instance, lizards can often be seen basking on them - but for those of us living or working in cities, especially with relatively new and smooth-surfaced buildings (and more air pollution), the opportunities to see such species can be limited.

Some are so strongly associated with this type of habitat that their common names reflect it, such as the wall pennywort Umbilicus rupestris (the generic name reflects its other common name, 'navelwort'). Like many wall-dwelling species, they are also found on natural rocks, but man-made rocky surfaces can be just as good.

The round leaves of wall pennywort Umbilicus rupestris.

You can see pale green lichenous growth here, but a closer look around this wall revealed a somewhat more impressive display - the little trumpet-like fruiting bodies of the lichen Cladonia (one of several similar species).

A cluster of Cladonia

There were also larger growths of non-lichenous fungi among the damp, mossy hollows. One was the branched and spindly Grey Coral Clavulina cinerea. This is a common species but being associated with the ground in woodlands, might not seem a likely wall-colonist. However, the crevices were full of moss and soil, and roots were present from the woody plants on top of the bank the wall retains. So, from the fungus' point of view, just like home! Another was an attractive orange-red waxcap Hygrocybe sp., possibly H. helobia which was only described scientifically in 1974 and is more often associated with grassy woodland clearing or heaths (but again, conditions are suitable in this wall). However, without closer examination (beyond what I'm likely to do on holiday), the species-level ID remains tentative.

Grey Coral fungus Clavulina cinerea

Waxcap Hygrocybe sp.

Moving through the major taxonomic groups, there are also ferns associated with walls. One of these is the rustyback Asplenium ceterach which I initially thought I had found; however, closer examination (yes, sometimes even on holiday, though it took iSpot to confirm it as I don't ID ferns very often...) showed it to be A. adiantum-nigrum, though both are common in SW England. Another (which I can also find growing from crevices in the walls of the church near where I live) is the maidenhair spleenwort A trichomanes.

Asplenium adiantum-nigrum (upper surface of fronds)

Asplenium adiantum-nigrum (lower surface of frond showing red-brown sori)

Maidenhair spleenwort Adiantum trichomanes

Lastly I want to return to the flowering plants, this time a non-native garden escape Nerine bowdenii, also known as the Guernsey Lily. This southern African species is a popular plant in the village of Slapton and can be seen along the narrow lanes outside many of the cottages. However, coming from mountainous areas, it too can adapt to 'mural' life and at least one had managed to escape through a garden fence and grow on top of the old stone wall featured here. I could continue - after all, with all these plants, fungi and lichens, there are of course many invertebrates (my usual topic!) - however, as I promised my wife I would not spend the week rummaging around with collecting pots, these will remain mysterious for now and I'll simply leave you with the big pink lily which, although appearing delicate, was clearly capable of surviving repeated buffeting by passing vehicles...

Guernsey Lily Nerine bowdenii.

Attack of the swimming saucers

Continuing with the theme of true bugs (Hemiptera) in ponds, not all are elongate, sluggish ambush-predators - others actively chase prey and one such species is the common Saucer Bug Ilyocoris cimicoides, the common name coming from its relatively broad, convex shape.

Saucer Bug Ilyocoris cimicoides

Unlike many aquatic bugs, the middle and hind legs are only slightly modified for swimming (there is some flattening, plus clear rows of swimming hairs), and can be used very effectively for walking on land. The front legs are however more strongly adapted, not for swimming but for seeking prey.

Ilyocoris cimicoides - ventral view showing hooked front legs

The hooked legs are used for sifting through sediment and detritus, and for grasping prey which is then pierced by the rostrum - humans should take care when looking through pond-nets as the bite can be very painful and includes toxic saliva causing a sensation equivalent to a bee or wasp sting (at up to 15mm long excluding appendages, it is moderately large insect). The front legs are shown clearly in the side view below, including the broad femur (for strong internal muscle attachments) which have long grooves on the underside which presumably help to grip prey and may form slots where the hooked tibia fits into it when the leg is folded shut.

Although it may be unfamiliar if you've never been pond-dipping, it is widespread though local in distribution and can be common in some waterbodies, especially in the weedy margins of large water-bodies such as marshy dykes, old canals and lakes/large ponds.

Ilyocoris cimicoides - side view showing hooked front legs and slightly modified mid- & hind legs

Note that there is now a second species of saucer bug of the family Naucoridae in Britain - Naucoris maculatus which has been found in England and may well spread being a strong flier (Denton 2007). Happy pond-dipping!

Reference

Denton, J. (2007). Water Bugs and Water Beetles of Surrey. Surrey Wildlife Trust, Woking. [Covers a good range of species; lots of useful info and excellent photos even if you're not in Surrey].

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