picture catches the details of diagnostic value. The underside has an orange
‘eye’ which together with the ‘antennae’ may confuse a predator. The family
Lycaenidae, commonly called ‘blues’ in English, encompass over 400 species
in Thailand. Many are now rare due to their adaptations to a lost world.
The common tit is not a bird, it is a
purple-blue lightning, it is a longan pest, it is a two-faced Janus, it is
the butterfly Hypolycaena erylus (Lycaenidae).
The ‘common tit’ is common in Chiang Mai and throughout its range including
northern India and Southeast Asia. What is not seen is that the two pairs of
swallowtails of the hind wings move. The outer pair mimics a pair of
antennae, complete with club-like structures. The inner pair resembles a
pair of front legs.
The purpose of being a Janus is to
trick enemies trying to sneak up on the butterfly. Thanks to the movements
of the fake antennae, the enemy would think the rear is the front, and when
trying to go behind this wary butterfly will see the enemy and escape. The
tails break easily if caught between jaws and the butterfly still survives.
The larva feeds on a variety of host plants, including longan, cinnamon,
kapok, Indian jujube and Senna.
The butterfly is wild and was not caught with a net. It came to sip water
and minerals from my hand. If you wish to identify some of your own Chiang
Mai garden butterflies, you can compare with the Dokmai Garden list which
includes some of the most common ones.
A good book on butterflies is Pisuth
Ek-Amnuay’s ‘Butterflies of Thailand’ with more than 1000 species.
www.dokmaigarden.co.th. [email protected] garden.co.th.