RUTELINAE MacLeay, 1819
Shining Leaf Chafers
This is a large and cosmopolitan group of chafers, sometimes referred to as a tribe and second in size to the Melolonthinae Samouelle, 1819 (about 11000 species), it is a mainly tropical group of about 4200 species in 200 genera and up to 9 tribes (it varies) e.g. the Hopliini Latreille, 1829, more correctly placed in the Melolonthinae Leach, 1819, is sometimes included and there are many specimens worldwide waiting to be named. The Neotropical region has about 1350 species, and by comparison the European fauna includes 63 species although many occur only in southern regions and only 2 extend north into Fennoscandia and the UK. Other temperate areas such as Asia are relatively diverse but in comparison with the tropics. Adults are usually very varied but usually brightly coloured and often striking in appearance though in general they lack the horns or other exaggerated outgrowths to the head or pronotum seen in some other groups of chafers. Many species are diurnal and very conspicuous, flying around flowers or larval host material in bright sun and often swarming, while others, especially in tropical regions, are nocturnal and sometimes attracted to light in huge numbers. The adults of some species do not feed at all and some may feed only for a brief while but many feed on nectar, pollen, flower parts, fruits or leaves of both angiosperms and gymnosperms. Eggs are laid in the soil or among decaying vegetation and the larvae of most develop in the soil feeding on roots and organic matter, most feed voraciously and develop quickly, and because they tend to occur in numbers and may be widely polyphagous a few species have spread from their native areas, usually with the transport of plant material, and become serious pests, and some have become agricultural pests in their native regions. Pupation occurs in the soil, usually at some depth and almost always in an earth cocoon constructed by the larva using soil particles and oral secretions. Adults of most species, especially in temperate regions, tend to emerge from the soil in numbers and at fairly specific times and have narrow seasons of occurrence. Species in temperate regions are either univoltine or may take two or more years to complete their life-cycle, some may be univoltine over parts of their range but may take longer where temperature or food is limiting. The Japanese beetle, Popillia japonica Newman, 1838, is typical of how some species have become pests, it is native to Japan and was unintentionally introduced to the Azores in the 1970s, the first records from mainland Europe was from 2014 when swarms were found near Milan and since that
time it has been recorded from many locations, it is now regulated in the European Union and may well find its way to the UK where it could have an impact on commercial horticulture. The first North American record was from 1911 and since then it has spread widely across the eastern states and southern parts of Canada and it is an occasionally serious pest of a range of plants. Adults feed on leaves and stems, often skeletonising leaves and killing growing shoots while larvae feed indiscriminately on a very wide range of root at depth in the soil; adults will feed on the foliage of more than 300 hosts in 79 plant families and will also consume fruit while it is developing on the plants. Control is difficult because larvae may go undetected until the damage is severe, they are also capable of moving through the soil to find fresh host material, and adults may swarm and disperse suddenly, they fly well and have been detected at 2.75 miles from their origin. After emerging and a period of feeding, adults move up into tree foliage to continue feeding and to mate and disperse, females then return to the soil to oviposit and so their presence is not always obvious; young larvae feed among roots but when larger, in the autumn, they burrow deeper to overwinter and generally go undetected.
Notwithstanding the very diverse appearance of the adults due to the metallic and often brilliant colouration, members of the subfamily are otherwise fairly uniform and differences between the tribes tend to be in the detail rather than in gross morphology and superficially they resemble many members of the Melolonthinae and Cetoniinae. The following tribes seem to be generally accepted and stable, at least for the moment.
GENIATINI Burmeister, 1844 includes about 330 described species in 13 rather poorly studied genera. The group is restricted to Neotropical region where many inhabit deciduous forests and cloud forests, they fly well and large numbers have been sampled at light. Little is known of the biology of most species but where known they are typical with larvae developing in the soil and adults grazing foliage, sometimes extensively defoliating plants. They are typical of the subfamily; many are rather drab brown or bicoloured brown and yellow although the group also includes some very impressive shiny metallic species.
ANOPLOGNATHINI MacLeay, 1819 is divided into five subtribes, all of which occur only in the southern hemisphere; two in Australia and three in South and Central America. Anoplognathina MacLeay, 1819 with 7 genera and more than 60 species, and Schizognathina Ohaus, 1918 with 13 genera and about 50 species are Australian. Brachysternina Burmeister, 1844 with 3 genera and 17 species is from Argentina and Chile, the monogeneric Phalangogoniina Ohaus, 1918, with 8 species, is restricted to Central America, and 62 species of the monogeneric Platycoeliina Burmeister, 1844 occur in South America. So far as is known they are typical of the subfamily with diurnal phytophagous adults and larvae developing in the ground.
ANATISTINI Lacordaire, 1856 includes 4 genera, all of which are restricted to the Neotropical region; from Honduras south to Brazil (Mato Grosso). The group is sometimes referred to by the older name of SPONDOCHLAMYINI. Members mostly occur in cloud forest habitats in northern areas, they are diurnal or nocturnal and sometimes come to light in numbers. Many are distinctively elongate-oval in form and glabrous, or nearly so, and many have relatively long legs; they are medium-sized beetles, many are drab but some are bright green or red and some have the common name of wax beetles.
ADORETINI Burmeister, 1844 is an Old World tribe of two genera. Metadorodocia Machatschke, 1957 includes two species and is endemic to Madagascar. Adoretus Dejean, 1833is a large and widespread genus of about 475 species, most occur in Asia, only 2 have been recorded from Europe and both are accidental introductions, The genus includes some notorious pest species e.g. A. sinicus (Burmeister, originally from Japan and Taiwan, is now widespread through Southeast Asia and is present on many Pacific Islands; it has been established on Hawaii since the 1890s. Adults and larvae are widely polyphagous on horticultural and agricultural products; adults feed nocturnally on foliage while larvae are subterranean, they are continuously brooded in tropical areas and the life cycle from egg to adult is complete within 6-7 weeks; under good conditions the larvae are fully-grown within 3 weeks, each instar taking about a week.
ALVARENGIINI Frey, 1975 includes 2 genera and 3 species from South America but very little is known of the tribe.
RUTELINI MacLeay, 1819. This large tribe includes about 1100 species, it is very diverse in tropical and sub-tropical regions worldwide and only poorly represented in temperate areas; none occur in Europe and of the 70 or so New World genera only 8 occur in the United States. The greatest diversity is in Central and South America. The tribe is divided into several groups which might loosely be called subtribes but they are artificial and in need of revision e.g. the Areodina group includes about 50 species of 10 genera, all occur in the New World with the exception of 4 species of Xenoproctis Kolbe, 1896 which are restricted to Africa, the Pelidotina group includes almost 400 species in 18 genera and with the exception of the 20 or so species of Peltonotus Burmeister, 1847 (an Old-World genus sometimes included in the Dynastinae), is restricted to the New World. The largest group, Anticheirina, with more than 360 species in 43 genera, is generally distributed worldwide but, as with the tribe in general, there are many genera and species of restricted distribution. Heterosternina includes about 20 species of 10 genera and occurs only in Central America while the Rutelina, with almost 150 species in 10 genera, is South American. Two groups occur only in Southeast Asia: Didrepanephorina with about 40 species in 5 genera, and Parastasina with about 110 species in 4 genera. Unlike most of the subfamily, some members exhibit exaggerated morphology; some species of the New World genera Heterosternus Dupont, 1832 and Chrysina Kirby, 1828 have enlarged hind femora, while some Asian species of Fruhstorferia Kolbe, 1894 and Peperonota Westwood, 1841have large thoracic or mandibular horns. Many are drab grey or brown with various markings but the group includes some truly beautifully-coloured species, notably among Chrysina, some of which have a brilliant-metallic and mirror-like reflection, earning them the common name of Jewel scarabs and a huge popularity among collectors.
ANOMALINI Streubel, 1839. With about 1300 species and 14 genera the Anomalini Streubel, 1839 is the largest of the tribes, it has a worldwide distribution and is dominated by one of the largest genera in the animal kingdom, Anomala Leach, 1819, with about 1200 species but this is likely to change as the tribe is badly in need of revision. Anomala is widespread in tropical regions but is primarily an old world genus; about 180 species occur in the new world of which 48 are listed from the Nearctic region, and while the genus is very diverse in Asia and Africa only 9 species occur in Europe of which one, A. dubia (Scopoli, 1763) extends north to the Nordic countries and the UK. Callistethus Blanchard, 1851 includes most of the remaining species; about 130 species occur worldwide of which about 60 occur in the new world, mostly Central and South America. Of the 30 species of the very widespread genus Phyllopertha Stephens, 1830, only P. horticola (Linnaeus, 1758) occurs in Europe, including the UK. The tribe is otherwise absent from the UK and only poorly represented in Europe, with 7 species of Mimela Kirby, 1825, 5 species of Exomala Reitter, 1903 and 3 species of Blitopertha Reitter, 1903. Members are quite typical of the tribe as a whole; varying in size and colour but fairly represented by Anomala and Phyllopertha. So far as is known the adults feed on foliage and the larvae develop underground, feeding on a variety of roots.
ANISOPLIINI includes about 90 species in 9 genera and occurs in warmer regions of the Palaearctic, Oriental, Ethiopian, Nearctic and Neotropical regions. The European fauna is relatively diverse, most occur in warmer southern regions and none extend to the UK. Of the 65 species of Anisoplia Schoenherr, 1817, 35 occur in Europe but most of these are restricted to southern and eastern regions. Brancoplia leucapsis (Laporte, 1840) is a widespread Asian species extending into Asia Minor and Caucasus. The single species of Anthoplia Medvedev, 1949, A. floricola (Fabricius, 1787), is widespread in northwest Africa and extends into southern Spain. Chaetopteroplia Medvedev, 1949, includes 12 species and with the exception of the widespread European C. segetum (Herbst, 1783) is restricted to the Middle East. Hemichaetoplia Baraud, 1986, includes 4 species of which one, H. pallidipennis (Gyllenhal, 1817) occurs in North Africa and Sardinia. Larvae develop underground feeding on a wide range of plant roots but in general they consume various grasses and many have become pests of cereal crops worldwide. Adults are unusual as in all known cases they feed exclusively on the pollen of various monocotyledonous plants.
POPILIINI Sometimes included as a subtribe of the Anomalini, this is an old world group of two genera. Pharaonus Blanchard, 1851 includes 6 species of arid regions in Asia and Africa. Popillia Leach, 1826 is a large genus of about 250 species, they are most diverse in Asia but also speciose in Africa and one, P. japonica, has become established worldwide due to human trade.
The UK species can be identified by the paired and unequal pro-tarsal claws and the body which is metallic, at least in part. Adults of the Anomalini in general may be recognized as follows: Labrum produced horizontally with respect to the clypeus, antennae usually nine-segmented, elytra with a membranous lateral margin, pro-tibiae bidentate; the inner spur subapical (although the inner spur is lacking in some exotic species and in some they are tridentate) and the terminal spiracle not situated in the pleural suture. They are medium sized and robust beetles varying in colour from drab brown or grey to bright metallic and glabrous or only sparsely pubescent above, many species are bicoloured with the foreparts and elytra contrasting, and in most the ventral surface is densely pubescent. Typically the head is narrower than the pronotum, with large and only weakly convex eyes and proportionally short antennae; males may have distinctly longer antennae but they are not dimorphic to the extent seen in many species of Melolonthinae. The pronotum is typically transverse, rather flat and lacking exaggerated sexual characters although there are often very obvious differences in outline between the sexes. The scutellum is always large. The elytra usually have well-impressed and punctured striae which extend at least into the apical third but they may be obscured by a general rugosity or punctation in the interstices. In many cases the male elytra are narrower and more elongate when compared with the female. Our UK species are readily distinguished as follows:
Smaller, 7-12mm. Forebody black with a metallic green reflection, elytra unmetallic pale to dark brown. Pronotum with sparse long pubescence and sinuate laterally towards the base.
Larger, 11-15mm. Forebody metallic red, green or blue, sometimes with the pronotal margins brown, elytra metallic red, green or purple; sometimes they appear brown but when viewed from a certain angle the metallic colouration becomes obvious. Pronotum without long pubescence, broadest at or just before the base and evenly curved laterally.