Friday, March 20, 2015

Sarawak: Gua Raya

Chupak, besides being a rice-growing area, first-class birding and dragonflying spot, and the best (only?) place near Kuching to find Pin-tailed Parrotfinches (Erythrura prasina; see my last two posts), is a lovely, pastoral place - a veritable hidden valley.  I'm ending a rather long dry spell between postings (while I was finishing the text for a book on butterflies, among other things) to go back there, and pick upwhere I left off: out at Chupak with Vincent Wong, on September 3, 2013.

The rice fields at Chupak are surrounded by limestone hills.  This is karst country, ridled with caves. There are some well-known ones in the Kuching area, including the much-visited Wind Cave and Fairy Cave, but Chupak has one of its own.

The Chupak cave system, midway between the kampungs (or villages) of Chupak and Skuduk, is called Gua Raya, which apparently means 'Big Cave'.  It was once, so they say, a hiding place for communist insurgents.  If you want to see what it looks like inside, go here; I confess caves make me rather nervous.

There is, however, a very pleasant little boardwalk to the cave entrance that takes you along the edge of the hillside forest.  At the mouth, where it ends, a blast of cool air from inside the cave provides welcome relief from the scorching midday heat and creates a little microclimate of its own.

The shiny green leaves of the trees along the walkway are welcome eye relief, too, after the sameness of the rice fields.

The three-lobed, hairy leaves of this little tree identify it (I hope) as a species of mahang (Macaranga), a member of the Euphorbia family (Euphorbiaceae).  Macaranga includes a number of species that live in commensal relationships with stinging Crematogaster ants.  The ants live in their hollow stems, and the tree provides them with a sugary solution from extrafloral nectaries (that is, glands that produce nectar but are not part of the plant's flowers).  In return the ants guard the plants from insect pests.  This relationship has been going on for some 16 to 20 million years.

The pests, though, have tricks of their own.  About 8 million years ago, scale insects invaded this two-way relationship.  They suck the plant's juices, but produce honeydew, a sugary solution that apparently bribes the ants to not only leave them alone, but to protect them.

oakblue Arhopala sp
Some two million years ago, a third type of insect horned in.  The caterpillars of some species of oakblue (Arhopala) began feeding on ant-guarded Macaranga leaves, and paying off their ant protectors with honeydew of their own.  Perhaps this oakblue was in the neighbourhood because of the Macarangas.  I can't be sure, because identifying Arhopala butterflies to species is fiendishly difficult.  There are, besides, hordes of them.  Pisuth Ek-Amnuey lists 95 species in the second edition of his Butterflies of Thailand; he calls Arhopala the most difficult butterfly genus to identify.  I'm not even going to try.

Common Imperial (Cheritra freja)
Common Imperial (Cheritra freja)
This is another member of the gossamer-wing family (Lycaenidae), but an easier one to identify: a Common Imperial (Cheritra freja), one of a number of orange, black and white hairstreaks with long, elegant tails ( And, in this case, iridescent blue upper parts). Despite its name it is actually considerably less common than the quite similar Branded Imperial (Eooxylides tharis), and I was quite happy to encounter it.

Rustic (Cupha erymanthis)
This Rustic (Cupha erymanthis) was attractive, but proved to be a less than ideal photographic subject.

Tawny Bushbrown (Mycalesis anapita)
Tawny Bushbrown (Mycalesis anapita)
Mycalesis is another genus that can give butterfly fanciers reason to tear their hair. It has many  very similar species, but I think this one is a Tawny Bushbrown (Mycalesis anapita).  I do wish someone would write a complete guide to the butterflies of Borneo (though I will be very grateful for Honor Phillipps' guide to the commoner species once it appears).

Neurothemis cf terminata
Neurothemis cf terminata
Neurothemis cf terminata
Neurothemis cf terminata
 This dragonfly gave me a fair bit of puzzlement, sending me for repeated searches for something like it in my guidebooks or on the internet. The pattern of its wing venation - fortunately quite easy to see on the photographs - suggests a female Neurothemis, and females of N.terminata can sometimes, according to A.G. Orr's Dragonflies of Peninsular Malaysia and Singapore, have clear wings tipped with brown.

Striped Tree Skink (Apterygodon vittatum)
Finally, a common but endemic Striped Tree Skink (Apterygodon vittatum) clinging to the trunk of a tree.  It differs from most of our local skinks in being not only arboreal (well, I usually see them about a metre up on a tree trunk) but easily identifiable.  One of Borneo's nicer lizards, in my opinion.

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