Leaf beetles , seed weevils, flea beetles (Alticini)
This is a very large family of leaf- and seed-eating beetles, the vast majority of which are terrestrial. A relatively small number of species are associated with water plants and some of these feed at some part of the life cycle on submerged parts of the plant. Two groups are typically found in aquatic situations - Donacia (subfamily Donaciinae) and the subfamily Alticini.
Chrysomelids generally have rather grub-like bodies - though legs are present, the abdomen is usually swollen relative to the head and prothorax, has reduced or no sclerotisation and often is somewhat curled up. When mature, body length is generally in the range 2-15 mm. Alticini have small 1-2 segmented antennae, Donacia has larger 3-segmented antennae. Alticini have 0, 1 or 2 pairs of stemmata, Donacia has 5 pairs. The presence of 4-segmented ( Donacia ) or 5-segmented (Alticini) legs instantly separates semi-aquatic chrysomelids from other grub-like larvae (Curculionidae and Brentidae). Abdomen without gills, hooks, opercula or urogomphi, however in Donacia , the spiracles of the eighth abdominal segment are drawn into paired spines for piercing water lily tissue. The final abdominal segment forms an ambulatory lobe.
Donacia attaches by respiratory horns to submerged stems or roots of waterlily and other aquatic plants, tapping the stems for air while grazing on vascular plant material. Alticini may be found mining the stems or leaves of aquatic plants. Two species of Donacia occur in north Queensland and the Northern Territory. Alticini (flea beetles) are more diverse and widespread. Overall, around 3000 Chrysomelidae (Polyphaga: Chrysomeloidea) species occur in Australia.
Lawrence, J.F. and Britton, E.B. (1991) Coleoptera. pp. 543-683. In: CSIRO, Insects of Australia. Volume 2. Melbourne University Press, Carlton, Victoria.
Lawson, F.A. (1991) Chrysomelidae (Chrysomeloidea) pp. 568-593. In: Stehr, F.W. (ed.) Immature Insects. Volume 2. Kendall/Hunt Publishing Company, Dubuque, Iowa.
Reid, C.A.M. (1993) Donacia australasiae Blackburn: the sole representative of the subfamily Donaciinae (Coleoptera: Chrysomelidae) in Australia and New Guinea . Journal of the Australian Entomological Society. 32: 103-111.
Williams, W.D. (1980) Australian Freshwater Life: The Invertebrates of Australian Inland Waters. The Macmillan Company of Australia, Melbourne.