A rare subspecies of the Red-base Jezebel
The ongoing drought is not only stressful to plants, but also to animals. So far we have only received 6 mm of rain in August. The irrigation at Dokmai Garden attracts many animals, and also our increasing numbers of plant species. Recently I saw a mysterious butterfly fly up and down on the lawn, and it settled on a wet silaleng stone to have a sip of water. I grabbed my ancient camera and due to the thirst and the innocence of this newly hatched butterfly, I got a nice picture.
It turns out to be a new butterfly species to Dokmai Garden; ‘The Red-base Jezebel’ (Delias pasithoe, Pieridae), described by the Swedish naturalist Linnaeus already in 1767. When I read about the various subspecies in Pisuth Ek-Amnuay’s eminent book ‘Butterflies of Thailand’ (2006) I realized this subspecies is ‘siamensis‘, described by Talbot in 1928. Pisuth gives it 3 stars, indicating this is a rare subspecies. Japanese entomologists claim it is a northern Thai subspecies, which is confirmed by two other Thai records and now this report.
The larva feeds on plants from the family Loranthaceae. The only Dokmai Garden record so far of this plant family is the parasitic Dendrophthoe longiflora. This parasite attacks a range of other woody plants and may kill them. The balance between plant displays, their health, and the concern about a rare subspecies of butterfly will be tricky. As the food plant is common around Dokmai Garden, I think we have to reduce the parasite within the garden but attract the butterflies from outside. However, this lovely butterfly and its larvae may be predators of the parasite and may eventually control it. Also the much more common ‘Painted Jezebel’ (Delias hyparete, Pieridae), another Dokmai Garden butterfly, feeds on this plant family.
Why would subspecies be important? They indicate genetic diversity within a species, and indicate local adaptations. To preserve a species, orchid or butterfly, one population in one forest may not be enough. We need a range of varieties and subspecies to assure enough genetic variation to cope with devastating fires, disease, invasive weeds, parasites and predators.