KATERETIDAE Kirby, 1837
False Pollen Beetles
Our two Brachypterus are among the most prolific beetles on flowers, Brachypterolus much less commonly so, and Kateretes
are associated with wetland habitats.
POLYPHAGA Emery, 1886
CUCUJOIDEA Latreille, 1802
Around the World
Formerly included as a subfamily of the Nitidulidae, the Kateretidae now includes 14 genera and about 100 species distributed mainly in temperate regions in both hemispheres although they seem to be absent from New Zealand. So far there is no higher order classification above the generic level. Several genera are restricted to certain regions e.g. the 8 species of Notobrachypterus Blackburn, 1892 occur in Australia while the 10 species of Neobrachypterus Jelinik, 1979 are Neotropical. Among general restricted to the Nearctic zone are Amartus LeConte, 1861, with 4 species, and the monotypic Anthonaeus Horn, 1879. The genus Platamartus Reitter, 1892 includes 2 species restricted to Siberia. Thirteen species in 6 genera occur in the United States and 9 species in 6 genera in Japan. The European fauna is relatively diverse with about 30 species in 6 genera, some of which are island endemics e.g. 4 species of Brachypterus Kugelann, 1794 occur on the Canary Islands; B. curtulus Wollaston, 1864, B. longimanus Wollaston, 1864, B. pattens Lindberg, 1953 and B. viridinitens Lindberg, 1950. Brachypterus includes 26 species and is mainly Holarctic with 3 species, including the adventive Eurasian B. urticae (Fabricius, 1792), occurring in the United States and a few more widely scattered e.g. B. rugosus Reitter, 1875 and B. troglodytes Murray, 1864 are Neotropical while B. metallicus Reitter, 1874 occurs in Australia. Ten species occur in Europe. The other European genera are:
Kateretes Herbst, 1793 is Holarctic and includes 10 species; 6 occur in Europe of which one, K. pusillus (Thunberg, 1794) is also widespread in Canada and the United States.
The Holarctic genus Heterhelus Jacquelin du Val, 1858 includes 4 species, 2 of which are Nearctic and 2 occur in Europe.
The mostly Asian genus Anamartus LeConte, 1861 includes 7 species, 2 of which occur in Europe.
Brachyleptus Motschulsky, 1845 includes 7 Palaearctic and Asian species, 2 of which occur in Europe.
The Eurasian genus Brachypterolus Grouvelle, 1913 includes 8 species, 6 are European of which one, B. pulicarius (Linnaeus, 1758), has been introduced into Canada and the United States and is now widespread.
All members of the family are small, 1.3-6.0mm and rather drab insects; most vary from some shade of brown to black and a few have lighter or darker markings and in this respect such species tend to be variable. Some species are metallic and the dorsal punctation varies from fine to very coarse and while some are glabrous most are to some extent pubescent. Habitus broadly elongate and rather depressed, with the elytra truncate leaving the pygidium as well as one or two, e.g. in Brachypterus, exposed abdominal tergites. The penultimate tergite is often produced backward laterally and this is a good guide to the family. Head prognathous and generally only weakly constricted behind the eyes, an occipital ridge is distinct in the Nearctic Anthonaeus agavensis but otherwise absent. The eyes are moderately convex and usually strongly protruding; glabrous and in most species with fine facets. Antennal grooves or ridges absent, the vertex and frons smoothly convex to almost flat and a frontoclypeal suture absent or only faint. The surface is variously punctured and pubescent. Mandibles short and sharp, and rarely visible from above, maxillae with galea and lacnia. Antennae inserted under the anteriolateral margin between the eyes and the mandibles; 11-segmented with a usually loose and weakly defined 3-segmented club, even when this is strongly defined the club is proportionally much narrower than in the superficially similar Nitidulidae. A single genus, Sibirhelus Kirejtshuk, 1989, with one Siberian (Irkutsk) species, lacks a club; here the antennae are gradually thickened towards the apex. Basal segments sometimes sexually dimorphic, being enlarged in the males, and sometimes greatly so e.g. in some Kateretes, but never with a curved scape. Pronotum quadrate to transverse and generally broadest behind the middle, the form of the hind angles varies from rounded to angled or produced posteriorly as in Brachypterolus. The lateral margins are finely bordered and either evenly rounded, sinuate or constricted in front of the hind angles. The posterior margin varies from almost straight to strongly sinuate and produced backwards medially. The post-coxal cavities are only partially closed posteriorly. Scutellum usually large and obvious, varying from transverse and triangular to curved. The elytra are broadly elongate and at least to some extent rounded laterally, the hind margin truncate, oblique or weakly curved and the surface lacks striae, the punctation random and varying from fine to very strong. The elytral pubescence varies and some species appear glabrous. Lateral margins finely bordered and this is visible from above only towards the base, not explanate or raised (as in some Nitidulids). The dorsal microsculpture is very variable. The hind wings are generally well developed. Legs robust; apical part of all femora visible from above, tibiae widened towards the apex with lateral margins lacking carinae or spines, each with 2 apical spurs on the inner angle, Tarsi 5,5,5; pseudotetramerous, segments 1-3 bilobed, sometimes strongly so and often with densely pubescent pads underneath. Claws toothed or simply thickened towards the base. Abdomen with 5 ventrites, the first sometimes with postcoxal lines. In males the eighth tergite is sometimes exposed and the fourth sometimes has a tomentose area. Pygidium large, deflexed and always obvious from above. The U.K. species are easily recognized by the exposed abdominal tergites, one of which is usually produced backwards laterally, and the gradually clubbed antennae.
Both adults and larvae are antherophagous, developing and feeding in the flowers of angiosperms; the larvae are monophagous or oligophagous while the adults are more general flower feeders, occurring on the host during mating and ovipositing. They often occur in large numbers during the summer and some species have been minor horticultural pests e.g. Brachypterolus vestitus (Keisenwetter, 1850) and B. antirrhini Murray, 1864 sometimes infest and damage flowers of cultivated antirrhinums in Europe. The hosts of many northern hemisphere species are well known while those of Neotropical and Australian species have yet to be discovered. Oviposition occurs in flower heads and larval development is rapid, 1-3 weeks. Pupation occurs in the soil or among leaf-litter below the host plants. Kateretids occur in a wide range of habitats from woodland and wetland to desert areas and species of some genera e.g. Brachypterus occur more or less wherever the host plant grows. The adults fly well and may sometimes be seen swarming around the host in warm weather, in temperate regions they are strongly attracted to various umbel flowers, and shaking these into a bag is a good way of sampling various species. Known hosts of several genera include Carex and Juncus (Kateretes), Carex (Platamartus) and Sibirhelus, Urtica (Brachypterus), and Antirrhinum and Linaria (Brachypterolus). The western Nearctic species Anthonaeus agavensis (Crotch, 1874) develops in yucca plants.
The U.K. fauna includes 9 species in 3 genera. Our 3 species of Kateretes occur in wetland areas on rushes and sedges in the spring, later they disperse and may occur far from any suitable habitat. They are all locally common and widely distributed in Southern England. Of the 4 species of Brachypterolus Grouvelle, 1913, 2, B. linariae (Stephens, 1830) and B. pulicarius (Linnaeus, 1758) are native and widely distributed, occurring in the flowers of Toadflax (Linaria sp.) B. vestitus (Keisenwetter, 1850) and B. antirrhini (Murray, 1864) are established introductions first recorded in the 1920’s, both are very local with scattered records from southern England (though both are probably under recorded), and both occur in the flowers of cultivated antirrhinum. Our 2 species of Brachypterus are common and often abundant throughout England and Wales, often occurring together in numbers on nettles and umbel flowers in almost any situation.