MEGALOPODIDAE Latreille, 1802
Large-Footed Leaf Beetles
The adults of our three species occur on tree foliage, where the larvae are leaf miners. Z. subspinosa is locally common, while the other two are less frequently found.
POLYPHAGA Emery, 1886
CHRYSOMELOIDEA Latreille, 1802
Zeugophora Kunze, 1818
Formerly included as a subfamily of the Chrysomelidae this small group includes about 450 species in 24 genera and 3 subfamilies and is cosmopolitan although predominantly tropical in distribution; only a relatively few members of the single subfamily Zeugophorinae Böving & Craighead, occur in the Holarctic region and local diversity is generally poor, in the Palaearctic region with a single species of Pedrilliomorphus Pic, 1917 from northeast India, and about 50 species of Zeugophora Kunze, 1818, and in the Nearctic region with 9 species of Zeugophora. More generally the Zeugophorinae includes more than 100 species in 3 genera; the monotypic Bruchomima Achard, 1916, 7 species of the predominantly southeast Asian Pedrilliomorpha and about 100 species of Zeugophora which extends south into the Old world tropics east to New Caledonia and includes several island endemics but unlike members of the other subfamilies most species in tropical areas occur at alpine altitudes above the tree-line and most are local and infrequently collected. The subfamily is unique in having leaf mining larvae and adults that feed externally on leaves, they are distinct among the family in having appendiculate and diverging claws with a distinct empodium, and pubescent, strongly and densely punctured elytra.
Palophaginae Kuschel & May, 1990 is a small group of 3 genera and 4 species from South America and Australia. Both Adults and larvae are pollen feeders on species of Araucariaceae. They resemble Zeugophora in having normally developed legs but have thinner, longer antennae and weakly emarginate and coarsely-faceted eyes. More generally they are recognized by raised and red or yellow coloured areas on the elytra.
Megalopodinae Latreille, 1802 includes the majority of species and is pan-tropical. Some larger genera are widespread e.g. the Old World Poecilomorpha Hope, 1840 (about 50 spp.) and Temnaspis Lacordaire, 1845 (about 65 spp.) but the remaining larger genera are restricted to particular areas e.g. the Neotropical Megalopus Fabricius, 1801 (about 30 spp.), Agathomerus Lacordaire, 1845 (about 20 spp.) and Matostethus Lacordaire, 1845 (about 13 spp.), and Africa is particularly diverse with e.g. Leucaster Stal, 1855 (about 26 spp.), Macrolopha Weise, 1902 (about 21 spp.) and Antonaria Jacoby & Clavareau, 1905 (about 14 spp.), and Colobapsis Fairmaire, 1894 (about 30 spp.) occurs on both continents. Unlike Zeugophorinae the group is rare outside warmer tropical regions and does not occur in Australia or New Zealand, island endemics are rare and only relatively few monotypic genera are known e.g. Macroantonaria Pic, 1951 from The Congo, Nickimerus Gúerin, 1948 from Brazil or the Neotropical Barticaria Jacoby & Clavareau, 1905. So far as is known all species are saproxylic with stem-boring larvae and sap feeding adults.
Both the present family and Orsodacnidae were previously classed as subfamilies of the Chrysomelidae but recent studies on both adult and larval morphology as well as phylogenetic analysis have shown both to be independent groups of family rank. Megalopodidae share many characters with both chrysomelids and cerambycids but are distinct in the structure of the genitalia, morphologically they are distinct from cerambycids in having the antennae mounted above the mandibles rather than on pre-ocular tubercles, and from Chrysomelids they may be recognized, at least among the limited UK fauna, by the form of the pronotum coupled with randomly punctured elytra and the general habitus; and with only 3 species of Zeugophora on our list this is a straightforward way of identifying them. All are small and rather flattened beetles, elongate in form; between 2 and 3 times longer than wide and, in Zeugophora <5mm, but some tropical species of the Megalopodinae may reach 7.5mm. Species of Zeugophora are rather uniform in appearance and members of other genera tend to be similar in terms of morphology but many differ most noticeably in the form of the hind legs which may be greatly developed, with enlarged and ventrally-toothed femora and strongly curved tibiae e.g. species of the North African genus Clythraxeloma Kraatz, 1879 or, where these features are perhaps best developed, species of the large, old world genus Temnaspis Lacordaire, 1845, the hence the vernacular name for the group. Some species of Temnaspis also have moderately thickened antennae but overall, in a superficially morphological sense, most species will be recognized as members of the family with a little experience. In tropical regions there are some strikingly coloured and metallic species but this is also true of many Holarctic Zeugophora e.g. Z. annulata (Baly, 1873) from Japan, conversely many tropical species are rather drab coloured e.g. many Neotropical Megalopus Fabricius, 1801. The following description refers to Zeugophora as this is the European representative of the family. Most are, at least to some extent and usually extensively, brightly coloured; red, yellow or blue, often metallic and with darker markings to the body that form distinct patterns or simply bicoloured. Most are have fine recumbent pubescence to the dorsal surface although this is not always obvious, while some have dense erect pubescence which is obvious to the naked eye e.g. the Nearctic Z. atra Fall, 1926. Head hypognathous; transverse from above with prominent eyes and short temples which are contracted towards the base, frons smoothly convex and without sculpture or impressions but usually strongly punctured , frontoclypeal suture distinct but otherwise without ridges or impressions on the frons, labrum transverse and rounded, truncate or emarginate anteriorly. Eyes variously convex and at least to some extent emarginate anteriorly. Antennae 11-segmented and filiform or weakly thickened or serrate towards the apex, inserted behind the mandibles, the insertions visible from above. Mandibles curved and relatively long; with small internal teeth towards the apex and bidentate apically, terminal segment of maxillary and labial palpi cylindrical to fusiform. Pronotum very characteristic; as wide as the head, quadrate or weakly transverse and with a large and distinctive lateral tooth, evenly convex and lacking lateral borders or explanate margins, surface usually strongly and randomly punctured. Anterior and posterior angles distinct, anterior margin simply curved, posterior margin sinuate or bisinuate. Scutellum small but usually obvious. Elytra broadly elongate and parallel-sided to distinctly narrowed in the anterior third, with broad rounded shoulders and continually rounded apices, epipleura incomplete; usually narrowly developed in the basal half and delimited by a fine ridge. Surface evenly convex and randomly punctured, at least as strongly as the pronotum but sometimes becoming weaker towards the apex. Hind wings well-developed. Legs relatively long and robust, pro- and meso-coxae strongly projecting and variously transverse, usually only weakly so, metacoxae flat and more strongly transverse, femora only weakly expanded and lacking ventral teeth, separated from the coxae by distinct trocanters; trocanter-femur joint strongly transverse. Tibiae more or less straight, without teeth or lateral spines and gradually broadened from base to apex, each with two short spurs on the inner apical angle; those on the pro-tibiae may be very small and hidden among a fringe of apical setae and so difficult to see. Tarsi 5-5-5 but may appear 4-4-4 as the small fourth segment may be hidden within the lobes of the third, segments 1 and 2 simply broadened or variously lobed, 1-3 densely setose ventrally. Claws strongly curved and with a basal tooth or lobe which may be very wide. Larvae are distinctive; pale and soft with a darker and well-sclerotized head, broadly elongate and strongly flattened, without legs and with each abdominal segment laterally produced and setose, they lack urogomphi and have lobed setae along the anterior margin of the labrum.
The central European fauna includes five species of Zeugophora of which 3 occur in the UK, all are distinct from superficially similar Chrysomelids e.g. some Criocerinae by the form of the pronotum. They are oligophagous on various broadleaf trees, the gregarious larvae mine host foliage, producing irregular blotch mines. Our species are readily separated using the following key:
Dorsal surface of body and appendages entirely pale brown. 3.2-3.6mm. A very local insect of the north eastern Scottish Highlands, on Populus tremula.
Dorsal surface bicoloured.
Head and pronotum pale orange-brown. Pronotum more densely and extensively punctured, the lateral tooth rounded and less prominent. 2.7-3.5mm. Widespread and locally common in south and central England, rare elsewhere and absent from Wales and Scotland, on Populus tremula.
Dorsal surface of head extensively black, pronotum pale brown. Pronotum more finely and less densely punctured, often with an impunctate central area, the lateral tooth angled and more projecting. 2.5-3.5mm. Very local and rare in southeast England; Surrey, formerly more widespread in the southeast.
Beetles of Britain and Ireland vol. 2
Andrew G. Duff
Provides keys and accounts on all the UK species.
Seed and Leaf Beetles
Michael L. Cox
Provides information on ecology and distribution.