This topic started due to this particular leaf beetle with a black body and a orange to red wing cases (elytra). After making some search, I am quite certain it is called Lilioceris cheni. The trigger is actually quite interesting. While on a field trip in October 2011, I saw this beetle chewing on the mid-air tuber of air potato (Dioscorea bulbifera). With this lead, I launched an Internet search to look for beetle that feed on air potato. It turned out that this beetle had been studied in the United States (U.S.) as a potential biological agent to control the invasive air potato vine. I have seen other leaf beetles over time but their background story is not as interesting as this one.

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The first time that I met this beetle was in September 2011, on the leaf of a rubber tree (Hevea brasiliensis). At that time, it was to me just another interesting beetle seen on a field trip. A month later, when I saw it for the second time on an air potato tuber at a totally different area, I was thrilled because now I know the diet of this beetle. When I went back the location where I spotted the first beetle, indeed, air potato vine was also abundant there.

The article by Pemberton (Biocontrol Science and Technology 2010;20(6):567-587) mentioned that a Lilioceris beetle that feed specifically on air potato was discovered in Nepal in 2002. This beetle was brought to the U.S. where series of investigation followed. It was concluded that the food of the beetle is very specific to that particular species of invasive air potato vine (Dioscorea bulbifera). Subsequently, this beetle was identified as Lilioceris cheni by Tishechkin (ZooKeys 2011;103:63-83). However, there was no photo of the beetle included in the 2 articles.

Based on the description in the Environmental Assessment (February 2011) by U.S. Department of Agriculture on the release of this beetle in the field, the beetle was described as one having "a shiny patent leather black color except for its tan/light orange or bright red wing covers" (page 3). This description fits rather well with the beetle that I had seen. In the September 2011 issue of the Invasive Plant Management Research & Outreach Newsletter (page 9) by Florida Fish and Wildlife Conservation Commission, field collection of the beetles was done in Yunnan Province in China and brought back to the U.S. for breeding. The released of this beetle in Florida is expected to take place in 2012.

While we are on air potato, there are 2 common species in Singapore. Besides the one mentioned above, the other one is Zanzibar yam (Dioscorea sansibarensis). The leaves of the mature vine are much larger when compare to that of Dioscorea bulbifera.

These orange beetles are usually found feeding on the leaves of Clerodendrum villosum shrub. At first, I thought that It is likely to be the Cucurbit Leaf Beetle (Aulacophora indica). However, Aulacophora indica prefers plants from the cucumber family (Cucurbitaceae). I have not seen the orange beetles feeding on the leaves of the 4 common wild members of the cucumber family here --- namely, Ivy Gourd (Coccinia grandis), Rough Bryony (Cucumis maderaspatanus), Gymnopetalum scabrum and Creeping Cucumber (Melothria pendula).

Later, I found a description of a "shining yellow brown" beetle that feed Seaside Clerodendrum (Clerodendrum inerme) in the Hong Kong Entomological Bulletin (2009, Volume 1, Issue 2, page 12) with an image of the beetle. The name of the beetle was Hoplasoma unicolor. Since the orange beetles I saw also feed on another Clerodendrum species, it is likely to be Hoplasoma unicolor. Hoplasoma unicolor appears to have a slightly longer and narrower body when compared to that of Aulacophora indica.

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I have not indicated the date where I saw this beetle as they are rather common and I had seen then many times.

In August 2011, I spotted this yellow beetle feeding on the flowers of the Bamboo Orchid (Arundina graminifolia). It is likely to be the Yellow Orchid Beetle (Lema pectoralis).

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In November 2011, I spotted at least 4 of these orange beetles feeding on the leaves of the Spiral Flag (Cheilocostus speciosus) plant. Each of them had a total of 4 tiny dark spot on their wing cases. Based on the picture found in the book, Singapore Biodiversity (page 359), I have identified this beetle as Lema quadripunctata. The book, Coleoptera, Chrysomelidae, 1908 (page 55) by Martin Jacoby, indicated that each of the elytron has two black spots.

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In July 2011, I saw a patch Primrose Willow (Ludwigia octovalvis) being attacked by this tiny blue metallic beetle and its larvae. There are plenty of them on each host plant in that area. It looks very similar to Altica birmanensis. However, the host plant of Altica birmanensis is Chinese Knotweed (Persicaria chinensis).

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The extent of destruction caused by the beetles can be seen in the 2 pictures below. The behaviour of this beetle toward Ludwigia and its life cycle had been studied by Nayek back in 1987 due to the beetle's potential as a biological control agent in rice field where the Ludwigia plant is prevalence (Life history and host-specificity of Altica cyanea, a potential biological control agent for water primrose, Ludwigia adscendens. Entomophaga 1987;32(4);407-414).

Additional references:
(1) Altica cyanea (Col: Chrysomelidae) for the biological control of Ludwigia prostrata (Onagraceae) in China. Tropical Pest Management 1990;36(4):368-370.
(2) Occurrence of Altica cyanea (Weber), a possible biocontrol agent for weeds in rice fields. Gujarat Agric. University Research Journal 1987;13(1):64.

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Apparently, some studies reported that Altica cyanea also attacked Straits Rhododendron (Melastoma malabathricum) shrub. However, I have not seen that in the field so far.

References:
(1) The potential of Altica cyanea Weber (Coleoptera: Chrysomelidae) as a biological control agent for Melastoma malabatricum Linn. MARDI Research Bulletin 1987;6:1.
(2) A Melastoma-feeding chrysomelid beetle, Altica cyanea. Malayan Nature Journal 41(2-3): 379-382.

Last updated: 20 November 2011