The lily and the voles

Merendera montana (L.) Lange from above
Merendera montana (L.) Lange from above

Merendera montana (L.) is a small, autumn-flowering plant, largely endemic to the Iberian Peninsula (Spain and Portugal). It is a member of the lily family (Liliaceae) and is widespread and common on heavily grazed grasslands, to which it is peculiarly adapted.  A high concentration of alkaloids – such as colchicine (1) – in the leaves ensures that it is avoided by herbivores, particularly sheep, during the winter period when the leaves are present.  The absence of leaves in the summer is probably another adaptation to avoid being consumed by grazing herbivores (1).  The bulbous plant then produces flowers from subterranean corms, in the autumn.  The flowers are particularly common on mountains and hillsides during the autumn months, such as October.  These photos of flowering Merendera montana were taken on 25th October (2013) in Galicia, Spain. 

Merendera montana (L.) Lange
Merendera montana (L.) Lange

The flowers have six petals and the stamens sport long yellow anthers.

Merendera montana

Although Merendera montana flowers often occur in great profusion, it seems that the greatest densities of flowers are found in association with the mole-vole, or Mediterranean pine vole, (Microtus duodecimcostatus) (2).  Spanish researchers have discovered that the burrowing behaviour of these little rodents helps to disperse and propogate the plants, which return the favour by supplying the voles with an abundant food source, especially in the form of the underground corms (2).

1) Gomez et al. (2003).  Seasonal and spatial variations of alkaloids in Merendera montana in relation to chemical defense and pathology.  Journal of Chemical Ecology 29(5), 1117-1126.

2) Gomez-Garcia et al. (2004).  How does Merendera montana (L.) Lange (Liliaceae) benefit from being consumed by mole-voles?  Plant Ecology 172(2), 173-181.

Zebra doves: an appreciation

Zebra finch (Columba striata)
Zebra finch (Geopelia striata)

Zebra doves (Geopelia striata) are small ground doves found throughout South East Asia.  They are commonly seen in parks and gardens where they walk about with a slow and purposeful manner, looking for food or feeding on grass seed.  They are an attractive bird with a soft cooing call, and are frequently kept as pets in some countries, such as Thailand.  They derive their name from the fine black and white barring on sides of the neck and down the breast.  The centre of the breast is an attractive pinkish/mauve colour, which is reportedly pinker and narrower in the female (1);  otherwise the sexes are similar.

Zebra finch (Geopelia striata) showing narrow pink strip on the breast
Zebra finch (Geopelia striata) showing narrow pink strip on the breast

I have come to greatly  appreciate the beauty of the plumage of these doves which is subtle and delicate.  For example, the blue eyes are ringed with a circle of pale yellow, whilst the base of the beak is a lovely pale blue.

Zebra finck (Geopelia striata)
Zebra finck (Geopelia striata)

Nests are made in trees and two eggs are typically laid – although three chicks were observed in a next in Singapore (2) – and incubated by both sexes for about two weeks.  The young leave the nest after a further two weeks or so, but according to my observations stay close to the parents and frequently beg to be fed.  The juveniles lack the blue and yellow coloration seen on the heads of the adults (see below).

Juvenile Zebra finch (Geopelia striata)
Juvenile Zebra finch (Geopelia striata)

On one occasion, I noticed a small group of three juvenile Zebra doves resting in the late afternoon sunshine with all of their feathers fluffed up (see below).  Presumably this behaviour is to drive out any parasites from their plumage, and shows to what extent the birds are able to erect all of their feathers, giving them a rather ugly appearance, not at all like their usual sleek appearance!

Juvenile Zebra (Geopelia striata) doves 'sun-bathing'
Juvenile Zebra (Geopelia striata) doves ‘sun-bathing’

1) http://www.hbw.com/species/zebra-dove-geopelia-striata

2) http://rmbr.nus.edu.sg/dna/docs/75472c4637b7fe1ef2b2509a4419bf2e.pdf

In praise of LBJs (Tree sparrows)

Asian tree sparrow (Passer montanus malaccensis)
Asian tree sparrow (Passer montanus malaccensis)

Tree sparrows (Passer montanus) are rather special birds in the Family ‘little brown jobs’ (!), having declined drastically in numbers in the United Kingdom since the 1970s, most probably as a result of changing farming practices.  There was even an Operation Tree Sparrow, which was launched by the RSPB and Natural England to try to halt the declining populations in the north-west of England (1).  Volunteers put up over 1,400 nest boxes for the sparrows and maintained hundreds of feeding stations on at least 85 farms (2).  The results were encouraging with a substantial increase in the numbers of tree sparrows on these farms; good news for tree sparrows and for lovers of tree sparrows! 

Fortunately, things are not so bad when looked at on a global scale: the species has a huge distribution which stretches all the way from western Europe, across Asia and down into S E Asia and Indonesia.  In the course of this so-called cline, there are a succession of different sub-species, at least 10 according to the HBW (3).   So, for example,  our own subspecies P. m. montanus is found right across Europe, but changes to P. m. transcaucasicus in the Caucasus region, and so on, until P. m. saturatus is encountered in  Japan, Taiwan, the Philippines, N Borneo and N Indonesian islands (3).  The subspecies exhibit subtle differences in colour tones and shades, as well as in sizes. For example, P. m. malaccensis (shown here), is a relatively dark race – with darker streaks on its upper parts – but is noticeably smaller than our own UK tree sparrow (P. m. montanus).  P. m. tibetanus on the other hand, which lives on the Tibetan Plateau and in central China, is  the biggest of all of the subspecies, probably as an adaptation to the cold.

So despite the spectacular ‘local’ declines of this species in places such as the UK (and Ireland), worldwide, the species does not appear to be suffering unduly, and its conservation status is ranked as being of ‘Least Concern’ N (4).  Remarkably, there may be somewhere between 159 to 576 million individual tree sparrows worldwide, with about 78,000,000-144,000,000 individuals (perhaps a quarter to a half of the total?) occurring in Europe, according to BirdLife International (4).  So seen as a whole, this species has a very large and stable population, despite fluctuating number and severe declines in some locations.  Let’s hope it stays that way.

Asian tree sparrow juvenile
Asian tree sparrow juvenile

The subspecies which occurs in Thailand (P. m. malaccensis) – where I took these photographs – is a very common bird seen in parks and gardens across the country.  These photos were taken in a hotel garden where the sparrows feed on grass seed, but supplement their diet with a variety of other pickings from the open air breakfast area!  It is probably an ideal habitat, being enclosed and largely protected from predators and with an all year round supply of supplemental food.  

Asian tree sparrow with bread
Asian tree sparrow with bread
Asian tree sparrow (Passer montanus malaccensis)
Asian tree sparrow (Passer montanus malaccensis)

1) http://www.rspb.org.uk/ourwork/projects/details/237330-operation-tree-sparrow).

2) http://www.naturalengland.org.uk/ourwork/farming/funding/es/agents/elsoptions/operationtreesparrow.aspx

3) http://www.hbw.com/species/eurasian-tree-sparrow-passer-montanus

4) http://www.birdlife.org/datazone/speciesfactsheet.php?id=8385

Thai Cruiser feeding on poinsettia flowers

I came across these butterflies feeding on poinsettias in early November (2013) when I visited the headquarters of the Doi Suthep-Pui National Park, Chiang Mai, Thailand. The butterfly is the Common Cruiser (or Thai Cruiser) Vindula erota erota Fabricius, 1793 (female). This species, especially the female, exhibits seasonal variation, and this is the dry-season form, even though the photograph was taken early in the dry season on 6th November 2013.

Common Cruuiser (Vindula erota erota) female feeding on poinsettia
Common Cruuiser (Vindula erota erota) female feeding on poinsettia

The butterflies were very active in the bright morning sunshine, flying between different flowers, as this photograph shows (albeit a bit blurred!).

Common Cruuiser (Vindula erota erota) female taking off from a poinsettia flower
Common Cruuiser (Vindula erota erota) female taking off from a poinsettia flower

The red leaves of the poinsettia are in fact bracts; the flowers are quire small and grouped together as a cluster (or inflorescence) known as a ‘cyathium’ (plural cyathia). See: http://www.euphorbiaceae.org/pages/about_euphorbia.html. The main feature of interest to butterflies is the mouth-like nectar gland which if found on the side of each cyathium. These little yellow cups contain nectar, and the butterflies can be seen inserting the proboscises into them in the next two photographs.

Common Cruuiser (Vindula erota erota) with proboscis inserted into cup-shaped nectar gland
Common Cruuiser (Vindula erota erota) male with proboscis inserted into cup-shaped nectar gland

Common Cruuiser (Vindula erota erota) Chiang Mai

The butterflies were also feeding on lantana flowers, inserting their proboscis down into the tiny florets.

Common Cruuiser (Vindula erota erota) female feeding on a lantana floret
Common Cruuiser (Vindula erota erota) female feeding on a lantana floret

Interestingly, I did not see any of the more colourful, orange-brown males; where were they? Perhaps off mud-puddling somewhere in search of salts to boost their prowess when it came to reproducing with these lovely ladies!

Jacintha Eggfly (Hypolimnas bolina)

I chased this butterfly along a road in Chiang Mai Zoo, last November (2013). It eventually landed on a fallen log and I was able to get this picture of it with its wing spread (Upperside).

The Great or Jacintha Eggfly (Hypolimnas bolina jacintha) Chiang Mai Zoo
The Great or Jacintha Eggfly (Hypolimnas bolina jacintha) female Chiang Mai Zoo

It took me a little while to identify it though, even with the help of the excellent book on the Butterflies of Thailand by Pisuth Ek-Amnuay. Anyway, it seems that this is a very variable species, exhibiting what is called phenotypic plasticity: in other words its varies both in size and colour pattern (but its only the females that show this variation apparently). The different subspecies can also interbreed according to Pisuth Ek-Amnuay, which can produce a range of hybrids which do not fit into the neat categories beloved of taxonomists! It shows that the idea of a fixed species type is sometimes at odds with what happens out there in nature, where individuals are constantly changing and adapting to circumstances as they occur. The reasons behind such variation is not always easy for us to understand, but seasonal variation in the size and colour of this species might help it adapt to its changing environment, particularly the wet and dry seasons in the tropics (see Kemp & Jones 2001, DOI: 10.1111/j.1095-8312.2001.tb01299.x).

The butterfly eventually flew off and landed on a leaf, where I was able to get a photo of its underside.

The Great or Jacintha Eggfly (Hypolimnas bolina jacintha) UW Chiang Mai Zoo
The Great or Jacintha Eggfly (Hypolimnas bolina jacintha) UW Chiang Mai Zoo

I had previously managed to get a shot of a very ragged male (below) which is smaller than the female, and has the light purple discal patches on the wings.  This particular male lacks thew white marginal and sub-marginal lines seen on some varieities, but it might just be very worn!

The Great Eggfly (Hypolimnas bolina jacintha) male UP Chiang Mai Zoo
The Great Eggfly (Hypolimnas bolina jacintha) male UP Chiang Mai Zoo

There are some terrific photographs of the larvae (caterpillars) and pupae (cocoons) of this particular subspecies on an excellent website of the Butterflies of Singapore (http://butterflycircle.blogspot.co.uk/2012/09/the-life-history-of-jacintha-eggfly.html). So many great resources on the web!

Reference
DARRELL J. KEMP & RHONDDA E. JONES (2001). Phenotypic plasticity in field populations of the tropical butterfly Hypolimnas bolina (L.) (Nymphalidae). Biological Journal of the Linnean Society Volume 72, Issue 1, pages 33–45, January 2001. http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8312.2001.tb01299.x/abstract.

Ang Ka Nature Trail – Doi Inthanon

The Ang Ka Nature Study trail is a ca. 360 mm wooden boardwalk near the top of Doi Inthanon, the highest mountain in Thailand (2,565m), which was reportedly designed by a Canadian biologist. It is very popular with bird watchers as well as other visitors wanting to experience a walk through the moist evergreen forest at the top of this beautiful mountain and admire the flora (especially the red rhododendrons, in season around January). The trees are covered in ferns and other epiphytes; sphagnum moss also covers many of the trunks in a mossy wrapping.

Fern-covered tree on Ang Ka Nature trail
Fern-covered tree on Ang Ka Nature trail
Tree covered in ferns and epiphytes on the Ang Ka trail
Tree covered in ferns and epiphytes on the Ang Ka trail

Unsurprisingly, it is often misty when walking this trail as it is near the top of the frequently cloud-covered summit.

Ang Ka Nature trail, Doi Inthanon (2)
Ang Ka Nature trail, Doi Inthanon (2)

When the sun does come out however, it reveals the colour and beauty of the forest.

Beautifully coloured trees on the Ang Ka Nature trail
Beautifully coloured trees on the Ang Ka Nature trail

Ang Ka4

According to one of the signs along the trail, Ang Ka means crow’s pond, but I don’t think there are any crows there! What there are, are a variety of Himalayan bird species, such as White-browed Shortwing (a regular), Green-tailed and Mrs Gould’s sunbirds, Rufous-winged fulvettas, Chestnut-tailed Minlas and many others. There is a very active population of Chestnut-crowned Laughing thrushes, which I have seen on every visit. These are very active and vocal birds, with a delightful variety of calls. They can often be seen moving along the wet forest floor, tossing aside leaves to look for invertebrates to eat.

Chestnut-capped Laughing thrush hunting for food on the wet forest floor.
Chestnut-capped-laughingthrush hunting for food on the wet forest floor.

One very active and noisy (courting?) couple jumped onto a branch so close in front of me that I had to quickly change my camera lens to get a half-decent shot!

Chestnut-capped Laughingthrushes (Garrulax mitratus)
Chestnut-capped Laughingthrushes (Garrulax mitratus)

A potter wasp – Phimenes flavopictus

Potter wasp (Phimenes flavopictus) Doi Pui.jpg
Potter wasp (Phimenes flavopictus) Doi Pui.jpg

Potter wasps make beautifully crafted pot-shaped nests out of mud and saliva: nature’s own potters! They are solitary insects and lay one or more eggs inside the nests (or pots) which they then provision with insects such as caterpillars or beetle larvae, for their offspring to feed on. I came across this beautiful specimen on Doi Pui in northern Thailand, which I identified as Phimenes flavopictus (Eumeninae), based on a better picture – far better than mine! – on the excellent Thailand Wildlife website (http://thailandwildlife.photoshelter.com/image/I00003PB4pNCpi.Q). I did not see the nest (pot) but the wasp appeared to be collecting soil or mud to take away to the unknown location. I wonder if the beautiful, slim, petiole-like waist – joining the thorax and abdomen – has a purpose?

Potter wasp (Phimenes flavopictus) on Doi Pui, Chiang Mai, Thailand
Potter wasp (Phimenes flavopictus) on Doi Pui, Chiang Mai, Thailand

Camouflage – in whose eyes?

When we look at beautifully camouflaged insects, such as certain butterfly species which look so much like the leaves or vegetation of their environment, we sometimes forget that they are not camouflaged for our eyes, but those of their would be predators, which might have better eyes than us (like a hawk or owl). Also, as creatures of flight – when they are perhaps the most exposed – they need camouflage to act in a different way from that when they are resting against a static background. Photography is a good way of revealing such adaptations. Rajah Brooke’s Birdwing (Trogonoptera brookiana) is one of the most attractive and distinctive butterflies found in South-East Asia.

Raja Brooke's birdwing (Trogonoptera brookiana)
Raja Brooke’s birdwing (Trogonoptera brookiana)

Each fore-wing has seven leaf-like bright green markings on the trailing edges, which are much brighter green on the males. The colouration of the females – which are reportedly secretive and elusive in nature – is much browner and duller. So, as the males are much more active, maybe they need the more vivid colouration to camouflage them as they fly. This idea occurred to me as I was reviewing photographs of the butterfly which I took in the excellent Kuala Lumpur Butterfly Park. It was only when I looked at the slightly blurred images – indicative of movement (well that’s my excuse for an out-of-focus image!) that I realised how clearly the wing marking resembled leaves – and perhaps the colourful shimmering butterflies confused predators with this array of vivid, leaflet-like patterns? Furthermore, I speculated, perhaps the colours and patterns of this insect only achieve their maximum effect (I am tempted to say purpose!) when the insect is in flight? In other words when the butterfly is moving in the vision of its would-be predator? Well it’s a thought! The world was not made just for our eyes.

Moving wing
Moving wing

Predation on butterflies

Black-patched metalmark (Lasaia agesilas)  with damaged hind wing
Black-patched metalmark (Lasaia agesilas) with damaged hind wing

Many butterflies we see happily flying around are not perfect specimens! Far from it; they often have chunks missing from their wings; presumably as a result of some lucky escape from a pecking bird. Such imperfections often only become noticeable in photographs, as these two examples show. Yet these are survivors; their camoflague, or behaviour, has been sufficient to allow these individuals to escape predation and to have the possibility of mating and passing on their genes to their offspring (assuming that they are still attractive to their mates!). Such is the stuff of evolution, the predators in this case acting as selectors of the best camoflagued against the existing environment; the strongest or the fleetest. I like to think we are all survivors of sorts, with out aging beauty or imperfect bodies still capable of going on to fulfil our destinies!

Chocolate pansy (Junonia iphita) with symmetrically damaged hind wings
Chocolate pansy (Junonia iphita) with symmetrically damaged hind wings