Adults: Variable in habitus and size, 0.9 - 40 mm. Tarsi pseudopentamerous: 5-5-5, with fourth segment small and hidden between the lobes of the split third segment, sometimes reduced to 4-4-4 (Cassidinae); basal tarsomeres ventrally with adhesive setae. Antennae nearly always filiform or slightly serrate, rarely pectinate, clavate only in one Bornean genus (Clavicornaltica); usually 11-segmented, sometimes with only 9 (Nonarthra) or 10 segments. Head not prolongate, hypognathous. Eyes varying from small to large; no eyeless species known. Pronotum and elytra of variable shape and structure, rarely with shortened elytra (some Galerucinae). Wings usually well-developed, reduced or absent in a a few species. Pygidium exposed in some groups (Bruchinae, Cryptocephalinae). Hind femora thickened in some groups (Alticinae, Sagrinae, some Bruchinae). Abdomen with five or six ventrites.
One of the most diverse beetle families in the World, currently containing about 40'000 described species.
Subfamily classification subject to different opinions among researchers. The classification here adopted treats Clytrinae and Fulcidacinae as tribes of Cryptocephalinae. Hispinae have been shown to be paraphyletic and are here included in Cassidinae. Alticinae is here treated as a subfamily, although often reduced to a tribe of Galerucinae. Bruchinae is here treated as a subfamily, while Megalopodidae (incl. Zeugophorinae) counts as separate family. The number of subfamilies recorded from Borneo therefore stands at 11.
Adults and larvae phytophagous or spermophagous. Adults usually feeding on plant leaves, often associated with their larvae. Larvae develop in various plant tissues, but excluding hardwood. Some groups specialised in seeds (Bruchinae). Other groups specialised leaf-miners (some tribes of Cassidinae). Many species strictly associated with a particular species, genus or family of host plants (monophagous or oligophagous). Some species found in leaf litter (e.g. Clavicornaltica).
Found in all habitats where plants occur, some species regarded as agricultural or forestry pest. Abundant everywhere on Borneo, in all types of forests, ruderal habitats, plantations, agricultural fields and gardens.
Most easily collected by beating or sweeping vegetation. Abundant in canopy fogging samples and flight intercept traps, also represented in malaise traps or in traps containing plant pheromones. Several species attracted to lights (especially Galerucinae and Alticinae).