Classification: | Kingdom: Animalia | Phylum: Arthropoda | Class: Insecta | Order: Coleoptera | Family: Chrysomelidae | Genus: Altica |

In July 2011, I saw several Ludwigia octovalvis (Primrose Willow) being attacked by these small blue metallic beetles and its larvae (pictures below). The beetle looks very similar to Altica birmanensis. However, the host plant of A. birmanensis is known to be Persicaria chinensis (Chinese Knotweed). Apparently, some studies reported that Altica cyanea also attacked Melastoma malabathricum (Straits Rhododendron) shrub [1, 2]. However, I have not seen that in the field so far.

The extent of destruction caused by the beetles and its larva can be seen in the picture below. The behaviour of this beetle toward Ludwigia species 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 (Creeping Water Primrose) [3, 4, 5].

Reference:

[1] Kamarudi KA, Shah AA. The potential of Altica cyanea Weber (Coleoptera: Chrysomelidae) as a biological control agent for Melastoma malabatricum Linn. MARDI Res Bull 1978;6(1):15-24.

[2] Ooi PAC. A Melastoma-feeding chrysomelid beetle, Altica cyanea. Malayan Nature Journal 1987;41(2-3):379-382.

[3] Nayek TK, Banerjee TC. Life history and host specificity of Altica cyanea [Coleoptera: Chrysomelidae], a potential biological control agent for water primrose, Ludwigia adscendens. Entomophaga 1987;32(4):407-414.

[4] Xiaoshui W. Altica cyanea (Col: Chrysomelidae) for the biological control of Ludwigia prostrata (Onagraceae) in China. Tropical Pest Management 1990;36(4):368-370.

[5] Jhala RC, Patel ZP, Shah AH. Occurrence of Altica cyanea (Weber), a possible biocontrol agent for weeds in rice fields. Gujarat Agric Uni Res J 1987;13(1):64.