A mating pair of flea beetles, Altica, at Ikutmaju Sawmill

On a chewed leaf in the bushes, Tanah Merah Mangrove Coast, Merotai Besar, Tawau, 25 October 2006, 08:15

Two shiny metallic blue-green beetles, one mounted on the other, at the tip of a green leaf with ragged, chewed edges and holes. — 08:15:59, the pair at the tip of the chewed leaf.

Close side view of the pair: the upper beetle's blue-green elytra densely punctured, its long thread-like antennae curving forward. — 08:16:52, close-up from the side.

Front and side view: the lower beetle's bronze-green elytra, the groove across its pronotum, its dark eyes and long dark antennae; the smaller beetle rides on top. — 08:18:28, the leaf on a wooden surface.

Cropped and reduced from the camera originals; nothing else changed. No flash.

The record

Date	Wednesday 25 October 2006
Time	08:15–08:18, a warm morning
Place	Ikutmaju Sawmill, on the Tanah Merah Mangrove Coast, Kampung Merotai Besar, Tawau, Sabah
Habitat	Bushes in the sawmill grounds, about 100 m from the wet mangrove. Damselflies, dragonflies and many other insects in the area
Substrate	A leaf, heavily chewed, with small dark droppings on it
Behaviour	Mating; slow and clumsy, with little movement
Number	One pair, adults
Size	Not measured
Camera	Canon PowerShot A410, three frames in two and a half minutes, no flash
Observer	Wong Fook Yee
iNaturalist	observation 406504137

Identification

Order Coleoptera · Family Chrysomelidae (leaf beetles) · Tribe Alticini (flea beetles) · Genus Altica.
Species not determined; Altica cyanea is possible.

Body oval and convex, shiny metallic blue-green with bronze-green highlights.
Elytra finely and densely punctured, without ribs.
Pronotum narrower than the elytra, with a groove across it in front of the base.
Antennae long and thread-like, about half the body length, dark; eyes dark and prominent.
Legs slender and dark. The beetle on top, the smaller of the two, is the male.

The colour, the groove across the pronotum and the long antennae fit Altica. Flea beetles jump with thickened hind thighs, but the hind legs are not clearly shown in these photographs, so that character could not be checked.

Remarks

The leaf was chewed full of holes and carried droppings, so the pair were probably feeding as well as mating on this plant. Its reddish leaf edge suggests a water primrose (Ludwigia), but the plant was not identified. Altica cyanea is known in South and South-East Asia as a beetle of water primrose, which is why it is suggested; the species cannot be confirmed from photographs.

Related: Tanah Merah Mangrove Coast: all records · Kampung Merotai Besar · Leaf beetles · Beetles · Two pairs of wings
Photographs © Wong Fook Yee. Locality, date, time and behaviour are the photographer's own; identification posted at genus on iNaturalist. Record page written 7 October 2026.