Neochetina eichhorniae Warner, 1970

Hendrich, Lars & Balke, Michael, 2004, Aquatic Coleoptera Of Singapore: Species Richness, Ecology And Conservation #, Raffles Bulletin of Zoology 52 (1), pp. 97-145 : 132

Neochetina eichhorniae Warner, 1970

Neochetina eichhorniae Warner, 1970: 487 ; O’Brien, 1976: 169- 170; DeLoach & Cordo, 1976: 643-652; Wright, 1980: 529- 535.

Material examined. – 2 specimens – Other areas - 2 ex., Lorong Banir, pond 1, 14 Jul.1995, NS 200, coll. H. K. Lua et al. ( ZRC) .

Distribution. – Argentina, west to the Andes, north to Panama and Trinidad and in southeastern Mexico. Introduced into the United States, Australia (Northern Territories and Queensland) and Southeast Asia as a biological control agent for the control of water hyacinth, Eichhornia crassipes ( O’Brien, 1976; Wright, 1980). Singapore!

Ecology. – All of the six species of the New World genus Neochetina are believed to be semi-aquatic and possess specialized aquatic adaptations including hydrofuge hairs and scales. Neochetina eichhorniae is known to breed in waterhyacinth, Eichhornia crassipes and E. azurea (Sw.) Kunth ( Warner, 1970) . The life cycle and biology of N. eichhorniae have been described in detail by DeLoach & Cordo (1976). Adult weevils feed on the leaves and the larvae tunnel into petioles and crowns. Larval tunnelling is usually followed by rotting of the plant tissues and can result in death of the plant. The species is known to be primarily nocturnal in habit and is also attracted by light ( O’Brien, 1976).

Remarks. – Water hyacinth Eichhornia crassipes Solms is a free-floating aquatic plant that was introduced into the United States, Africa, New Guinea, Australia and many parts of Southeast Asia from its native home in South America ( Brazil) as an ornamental plant in garden ponds. In Singapore it was introduced in 1893 from Hong Kong. It has since reproduced beyond control to become a serious aquatic weed in many countries where it completely covers slow-flowing streams, canals, and small lakes, and blocks the passage of boats. Since mechanical and chemical controls are expensive, pollute the water and require repeated applications, several Neotropical insects, feeding on Eichhornia , have been used as biological control agents (DeLoach & Cordo, 1976; Wright, 1980). Neochetina eichhorniae was first introduced to Thailand in the 1970’s and later spread to Peninsular Malaysia (Wright pers. comm.).