Cybister tripunctatus lateralis ( Fabricius, 1798 )

Hendrich, Lars & Balke, Michael, 2004, Aquatic Coleoptera Of Singapore: Species Richness, Ecology And Conservation #, Raffles Bulletin of Zoology 52 (1), pp. 97-145 : 121

Cybister tripunctatus lateralis ( Fabricius, 1798)

Dytiscus tripunctatus Olivier, 1795: 14 .

Dytiscus lateralis Fabricius 1798: 64 .

Cybister tripunctatus (Olivier) - Sharp, 1882: 727; Zimmermann, 1927: 43; Csiki, 1937: 130; Hendrich & Balke, 1995: 47; Chen et al., 1998: 27.

Cybister tripunctatus orientalis Gschwendtner, 1931: 99 .

Cybister asiaticus Sharp, 1882: 731 .

Cybister tripunctatus var. asiaticus Sharp, 1882 - Gschwendtner, 1923: 108.

Cybister tripunctatus asiaticus Sharp, 1882 - Régimbart, 1899: 352; Balfour-Browne, 1945: 122; Fernando, 1961: 24; 1964: 82, 86, 88; Vazirani, 1968: 290; 1977: 92; Nilsson, 1995: 79, and references therein.

Cybister sp. : Yang, 1991: 93.

Cybister tripunctatus lateralis ( Fabricius, 1798) - Nilsson, 2001: 90.

Material examined. – 5 specimens - Sungai Buloh - 1 ex., ponds, Apr.1989, ZRC. 6.1062, coll. P. Ng ( ZRC) ; 3 ex., ponds, 15 Nov.1990, coll. K. Lim & K. L. Yeo ( ZRC) ; 1 ex., ponds, Turut track, concrete tank by chicken farm, 6 Dec.1990, coll. C. M. Yang & K. L. Yeo ( ZRC) .

Distribution. – Widespread throughout the warmer Old World areas ( Régimbart, 1899; Zimmermann, 1920 & 1927; Vazirani, 1977; Watts, 1978; Hendrich & Balke, 1995; Nilsson, 1995). Singapore!

Ecology. – The species lives in various types of perennial, mainly open, standing and slow flowing waters, such as swamps, ponds, paddy fields, fish ponds, shallow lakes and irrigation ditches. The habitat must be rich in detritus and submerged vegetation. Cybister tripunctatus lateralis is frequently attracted to light and is one of the most common larger dytiscids in Southeast Asia.

Remarks. – Only selected synonyms are given here. The species and its subspecies are in need for a modern revision. According to Balfour-Browne (1945), this polymorphic species is represented in the Oriental Region by the subspecies C. t. lateralis ( Nilsson, 2001) .

It is sold as food in Northern Thailand and Hong Kong ( Chen et al., 1998); “particularly abundant in the autumn [...] large numbers are captured easily because at this time of the year they disperse to seek new bodies of water and they collect at lights at night” ( Hill et al., 1982).

FAMILY GYRINIDAE

The gyrinids or whirligig beetles have strongly adapted to life on the water surface film. The compound eyes are divided into a dorsal and a ventral one, probably mainly to detect predators, since the food, consisting mostly of drowning insects on the water surface, is located by the specially modified antennae that are sensitive to wave action. The long forelegs are used for grasping the prey. The extremely modified, paddle-like middle and hind legs propel the beetles with astonishing speed. They are often gregarious and move in circles on the water. Larvae breathe by gills and, like the adults, are primarily predacious. Pupation occurs on land in a cocoon formed by gluing particles of sand or debris around the mature larva. All Southeast Asian species are restricted to clear, oxygen rich, mostly fast flowing streams and rivers, some in ponds and reservoirs.