Are hawk moths getting uncommon in Singapore?

posted in: Butterflies and Moths, Fauna | 7

Lee Chiu San’s comment on hawk moth becoming rare in Singapore, in response to the post on Death’s Head Hawk Moth (Acherontia styx medusa) is food for thought:

“The reason why hawk moths are becoming more rare in Singapore nowadays could be that Javan Mynas (Acridotheres javanicus) find them delicious. Several decades ago, when Javan Mynas were not yet common, hawk moths of various types often flew into my home at night.

“Over the last two years there were times when I was delighted to find the easily recognisable hawk moth caterpillars on my garden plants. Sadly, they never lasted long. They were always eaten by birds, usually mynas, within a few days of being noticed.

“In years past, when aviculturalists depended more on wild-caught rather than farmed insects for feeding softbilled birds, pet shops both in Singapore as well as in Europe and America offered hawk moth caterpillars for sale.

“I have not seen any for sale locally for decades, and I don’t know if they are still offered by pet shops abroad. But they can be farmed in captivity. This LINK tells how to cultivate the European Hawk Moth, which is related to the one that our Webmaster has raised.”

Yes, caterpillars are a favourite food with many birds. And hawk moth caterpillars, being larger and more noticeable, are possibly commonly caught – see this post showing a Collared Kingfisher (Todiramphus chloris) catching a Privet Hawk Moth (Psilogramma menephron).

So it is possible that hawk moth population is declining. And if Javan Mynas are developing a taste for these caterpillars, the population of hawk moths may suffer.

On the other hand, in this small garden of mine, I had through the years, noticed their presence – three species in all. Early this year I came across a pair of hawk moth caterpillars on my Lime plant (Citrus x microcarpa) (above). I managed to photograph them but when I returned the next day they were gone – taken by Javan mynas?

And the Rodent Tuber (Typhonium divaricatum) plants that I maintain in pots, reputed to cure certain cancers, are regularly ravished by caterpillars of Pergesa acteus hawk moth (above; scale in cm and mm).

I only realised that the caterpillars were present when the leaves showed signs of being eaten (above). Subsequently I came across and adult after it emerged from the ground nearby (below: scale in mm).

About five years ago I encountered Amplypterus panopus (below) in my garden after it emerged from its underground chamber and its wings were about ready for flight.

Another species I accidentally came across was the Jade Hawk Moth (Daphnis hypothous). It was clinging on a compound leaf of my Starfruit (Averrhoa carambola) tree, probably just after emerging from the pupa (below).

Finally we should not forget the Hummingbird Hawk Moth posted earlier, taking necter by hovering in front of the flowers at the Singapore Botanic Gardens. An image of Macroglossum sp. hawkmoth by Johnny Wee is shown below.

So there are hawk moths around, in my garden as well as elsewhere, except that they are well camouflaged and so escape detection most of the time.

And it has been reported that their food plants number more than 100 species, so there should be no lack of food plants in Singapore.

In view of the above, are these moths actually getting rare or is it because people fail to notice their caterpillars and do not encounter the moths as they are nocturnal in nature?

Just for interest, the above shows a Yam Hawk Moth (Theretra nessus) that Dato’ Dr Amar-Singh HSS found recently in his garden in Ipoh, Malaysia.

YC Wee
Singapore
November 2015

7 Responses

  1. It just came to me that Lee Chiu San might well be right. Moths (as well as butterflies, etc) are not as plentiful as before. One reason may be that we are spraying insecticides on our wayside trees along selected roads. Also, the regular anti-mosquito spraying in private gardens, etc.

  2. Sun Chong Hong

    Agreed. One of my neighbours, a nature friend who has a special interest in spiders, lamented that he hardly see them in our condo nowadays.

    I have noticed that dragonflies seem to have disappeared from our condo too.

    • Well, one day we will have a beautiful green and colourful “city in a garden” but will not be bothered by much creepy crawlies? We want beautiful trees lining our roads and filling our gardens but do not want their leaves chewed up by caterpillars. We want to have a “forest” experience by living in condos by our nature reserves but do not want to be bothered by monkeys and snakes… Now what else???

  3. Adrian Chan

    The first caterpillar photo on the page above is a geometrid moth caterpillar and not a hawk moth caterpillar.

  4. Adrian Chan

    Try trapping them using a UV lamp at night !

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