Butterflies of Thailand, Malaysia & Borneo
Malay Baron
Euthalia monina  FABRICIUS, 1787

Euthalia monina monina, male, Taman Negara, West Malaysia  Adrian Hoskins
The genus Euthalia comprises of about 40-50 species, of which up to 18 occur in China or in the south-east Holarctic region, and the remainder in the Oriental region. The exact number of species has yet to be determined as the genus is under review, and the status of many is in doubt - some taxonomists regarding them as full species while others consider them to be merely subspecies.
Many of the 16-20 species occurring in Malaysia are quite difficult to tell apart, and identification is confounded by the fact that the males and females of each species are usually very different in colour and pattern, and because several of the species produce a number of different colour forms or morphs.
The male of Euthalia monina is illustrated above. The female lacks the green iridescence, being a dull earthy brown colour, beautifully patterned with numerous pale greyish markings on the outer part of the wings. It closely resembles the female of Tanaecia iapis.
Euthalia monina is the commonest member of the genus in Malaysia, and also occurs in Sikkim, Myanmar, Thailand, Sumatra, Palawan, Kalimantan, Lombok and Java.
This species is found in small clearings and glades, on river beaches, and along the wider trails in primary and disturbed rainforest habitats, at elevations between sea level and about 1000 metres.
There is very little published information about the lifecycle of monina, so the following is educated guesswork based on the lifecycle of other Euthalia species :
The eggs of Euthalia species are normally laid singly on the underside of leaves of the foodplants. They are very strange in appearance, being dome-shaped and covered in a coarse network of hexagonal depressions, the corners of which each bear a hair-like protuberance, which in some species is tipped with what appears to be a tiny drop of dew, but is in fact a minute glossy club.
Immediately after hatching, the caterpillar devours its empty eggshell. Thereafter depending on the species it feeds on the leaves of Dendropthoe, Loranthus, Elytranthe ( Loranthaceae ), Anacardium, Mangifera ( Anacardiaceae ), Litchi ( Sapindaceae ) or various other trees or woody parasitic plants. In Malaya and Singapore the larvae have also been found on Clidemia hirta, an invasive noxious weed imported from South America in the 19th century by Koster, which has since earned itself the name of Koster's Curse.
The larva is extraordinary, possessing a series of very long lateral spikes, each of which is adorned with a double row of horizontal spikelets. The body and spikes are yellowish in the early instars, but older larvae are normally green, and marked along the back in some species with a broad creamy stripe or a series of dark pink or yellow blotches. Contrary to what might be expected from such a description it is remarkably difficult to find, because the spikes break up the outline, merging with the veins of the leaf and effectively make the larva "disappear" when viewed from a distance.
The chrysalis, which is suspended by the cremaster from a leaf, is diamond-shaped in silhouette, and in cross section. It is pale green, with a prominent pale cream transverse dorsal ridge.
Adult behaviour
Males are often seen imbibing mineralised moisture from patches of damp ground, at which times they usually hold their wings outspread. It often takes them a few minutes to settle down and feed, during which time they hop and walk about from one spot to another, slowly fanning their wings. Females rarely settle on the ground, but are commonly seen basking on the lower foliage of trees.


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