LUCANIDAE | uk beetles

LUCANIDAE Latreille, 1804

Stag Beetles

This iconic family includes the largest of all European beetles - Lucanus cervus, which is local in Britain. The Lesser Stag Beetle Dorcus parallelopipedus is much more widespread and common, and very likely to be encountered.

POLYPHAGA Emery, 1886

SCARABAEIODEA Latreille, 1802

9-75mm

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Around the World

As currently understood the Lucanidae includes about 1500 species in 110 genera and 4 subfamilies, and is almost cosmopolitan, occurring from equatorial regions to high temperate latitudes worldwide. The greatest diversity is in Old World tropics, especially around Southeast Asia, and the New World is comparatively poor is species, this fauna includes 235 species in 41 genera representing all four subfamilies although the Lampriminae Macleay, 1819 is represented by only the monotypic genus Streptocerus Fairmaire, 1850, from Chile. On the other hand the morphological variation in Neotropical species is as wide at that from any other region, and the Nearctic fauna, with 38 species in 8 genera, compares favourably with other temperate region. Because of their often large size, spectacular appearance and exaggerated sexually dimorphic head and mandible development in the males they have always been popular with the public and collectors; a glance at eBay etc. will demonstrate how serious this is, and this popularity has generated a huge number of subs-specific and variety names but despite this there has been very little rigorous taxonomic work within the family and many groups need to be revised and keyed out; books about stag beetles have tended to be full of photographs and rely on comparative gross morphology to enable identifications, and even recent ones contain ambiguities and misidentifications. Higher level classification is also in need of rigorous revision as the number of subfamilies has varied greatly over the years and many tribal names are incorrectly founded and so of questionable validity. The family was long considered to be among the most primitive of the Scarabaeoidea but recent phylogenetic research places it in an intermediate group along with Glaresidae and Trogidae etc. and its closest relative family is the Diphyllostomatidae Holloway, 1972, formerly included within the Lucanidae. The world market in Lucanids involves two aspects, firstly private collectors obtain large amounts of material from the wild, sometimes for no other reason than profit, and sell or exchange it with collectors, the morality of this is a personal business but it is probably fair to say that many of the world’s finest collections have been, at least partly, obtained this way and probably continue to grow by this means, and so such collecting has probably had a very valuable contribution to science,

more especially so when measured against the horrific environmental vandalism seen in tropical areas of the world over recent decades. Secondly many species are bred for profit in impoverished tropical areas, as well as by private breeders the world over, this has no environmental impact and means that ordinary people can have stag beetle key-rings and ornaments, and coleopterists with a conscience can easily obtain specimens in order to study Lucanid morphology or larvae for rearing.

The European fauna, very broadly, includes 17 species in 7 genera; Spain, France and Italy are the most diverse regions with 9 species each and several countries list 7 e.g. Germany, Romania, Slovakia, Sweden, Switzerland and Czech Republic while there are 4 species on the U.K. list including the regionally extinct Platycerus caraboides. No lucanids appear to have been recorded from Iceland.The European list includes the following:

Aesalus ulanowskii Ganglbauer, 1887 (=A. daghestanicus Didier & Seguy, 1957) from Caucasus and Iran.
A. scarabaeoides Panzer, 1794 is widespread.
Ceruchus chrysomelinus (Hochenwarth, 1785) is widespread.
Dorcus alaxisi Muret, 1999 a Cyprus endemic, the only Lucanid to occur on the island.
D. musimon Gene, 1836 from Italy.
D. parallelipipedus (Linnaeus, 1758) is widespread, extending to the U.K.
D. peyroni Reich & Saulcy, 1856 from Greece and Iran.
Lucanus cervus (Linnaeus, 1758) is widespread extending to the U.K., it appears to be the only species protected by law in Europe.
L. tetraodon Thunberg, 1806 from France and Italy.
L. (Pseudolucanus Hope & Westwood, 1845) barbarosa Fabricius, 1801 from Spain.
Platycerus caprea (Degeer, 1774) is widespread.
P. caraboides (Linnaeus, 1758) is widespread.
P. spinifer Attems, 1938 from France.
Sinodendron cylindricum Linnaeus, 1758 is widespread.
S. persicum Reitter, 1902 from Iran and Azerbaijan.
S. caucasicus Parry, 1864 from Caucasus.

The world view is obviously much more impressive and complex but the majority of species will be recognized as ‘stags’, if not always quite typical of the group. The following very brief and necessarily incomplete view of the various groups is intended to give an idea of how the species are delimited and distributed.

Aesalinae Macleay, 1819 includes about 70 species in 3 tribes and 10 genera. They are atypical species, generally smaller and oval and lacking the splendid dimorphism of other groups. Members of the Aeselini Macleay, 1819 have the elytra covered in bristles or scales; 4 genera are included. Aesalus Fabricius, 1801 includes 12 Palaearctic species, Echinoaesalus Zelenka, 1993 includes 15 species from Southeast Asia, and the Neotropical Trogellus Paulsen, 2013 includes about 10 species formerly included in Aesalus. Nicagini Leconte, 1861 includes 3 species of the single genus Nicagus Leconte, 1861; 2 Nearctic and one from Japan. Ceratognathini Sharp, 1899 comprises 3 genera and is restricted to the Southern Hemisphere. Ceratognathus Westwood, 1838 with 15 species is Australian, the 9 species of Mitophyllus Parry, 1843 occur in New Zealand while Hilophyllus Paulsen & Mondaca, 2006 includes 3 Neotropical species formerly included in Ceratognathus.
Lampriminae Macleay, 1819 is a predominantly Southern Hemisphere group comprising 5 genera of mostly vividly coloured and metallic species, most are very strongly dimorphic with the male mandibles sometimes extremely developed. The single species of Dendroblax White, 1846 occurs in New Zealand, it is dull-brown to black and does not display dimorphism. Phalacrognathus Macleay, 1885 occurs in Australia and New Guinea, the single species is very variable, from black or dull chestnut-brown to bright metallic golden green. Lamprina Latreille, 1806 includes 8 strongly dimorphic and vividly metallic species from Australia and New Guinea, the monotypic Streptocerus Fairmaire, 1850 occurs in Chile, and Homolamprina Macleay, 1885, also monotypic, is Australian.
Syndesinae Macleay, 1819 includes 4 genera. They are small to medium sized and mostly parallel-sided species with dimorphic mandibles or a clypeal horn in the males. They are quite characteristic with orthocerous antennae and elytra often bearing rows of striae or carinae. The Holarctic Sinodendron Hellwig, 1792 with 4 species, and Ceruchus Macleay, 1819 with about 15 species have a 3-segmented antennal club. Syndesus Fourcroy, 1785 includes 4 Australian species which have a 7-segmented club, and the Neotropical Psilodon Perty, 1830, formerly included in Syndesus, includes 5 species with a 6-segmented club. A fossil species, Ceruchites hahnei Statz, 1952 is known from Germany.
Lucaninae Latreille, 1804 By far the largest subfamily with more than 1400 described species and more continually being described, especially from China, Japan, Southeast Asia and the Neotropics. This continual addition of material makes it difficult to assess generic affinities or the extent or validity of tribes and so the situation is dynamic. The list that follows gives some interesting examples from each of the currently accepted tribes of the subfamily and which are well worth a look. Members of this subfamily have geniculate antennae with a smooth scape i.e. without longitudinal grooves’ and a 3-6 segmented club with moderately transverse segments that do not close together and eyes partially to completely divided by a horizontal canthus. The legs are long and robust, the fore-legs often fossorial, sometimes more especially so in the females. Sexual dimorphism and allometry are widespread in the group. The pronotum and elytra can be indented, ridged or smooth, sometimes with pubescence or scales that may form a distinct pattern. Most are nocturnal and strong fliers but the fauna of some regions e.g. Australia, include many flightless species.
- Aegiini Maes, 1992. Aegus Macleay, 1819 is a very large genus of more than 220 species in 11 subgenera from China, Japan, Southeast Asia and Australasia. Sphaenognathus Buquet, 1838 includes about 30 Neotropical species.
- Cladognathini Felsche, 1898. The Holarctic genus Dorcus Macleay, 1819 formerly included about 65 species but has now been split into several genera. Metallactulus Ritsema, 1885 includes 5 species from the Caroline Islands. The 35 species of Prismognathus Motschulsky in Schrank, 1860 occur throughout eastern and Southeast Asia. The very large Southeast Asian and African genus Cladognathus Burmeister, 1847 includes many subgenera that are gradually being split onto distinct genera e.g. the large genus Prosopocoilus Westwood, 1845. Serrognathus Motschulsky, 1862 includes about 30 species from the eastern Palaearctic and Old World tropical regions.
- Colophonini Maes, 1992 includes about 20 species of the single genus Colophon Gray in Griffith, 1832 from South Africa.
- Cyclommatini Maes, 1992. Cyclommatinus Didier, 1927 with 7 species and many subspecies from Southeast Asia, and Cyclommatus Parry, 1863 with about 65 species from the same regions include some very impressive species.
- Dendeziini Benesh, 1955 includes 3 genera and 10 African species.
- Figulini Bermeister, 1847 includes 6 genera mostly from Southeast Asia. The genus Figulus Macleay, 1819 from Southeast Asia and South Africa includes about 150 odd-looking species; elongate and convex like Dorcus but with prominent mandibles. Cardanus Westwood, 1843 with 10 species occurs in Southeast Asia.
- Homoderini Maes, 1992 is monogeneric with 2 species and several subspecies of Homoderus Perry, 1862 from Africa.
- Lissapterini contains 8 genera and is restricted to Australia and New Zealand. Paralissotes Holloway with 7 species, and Geodorcus Holloway, 1996 with 6 species are endemic to New Zealand. Lissapterus Deyrolle, 1870 includes 8 Australian species, and Lissotes Westwood, 1855 includes about 30 species from Tasmania.
- Neoprosopocoilini Maes, 1992 is a Neotropical tribe of 9 genera including Leptinopterus Hope, 1838 with 35 very impressive species.
- Lucanini Latreille, 1806 includes 5 genera. One is monotypic; Chewlucanus Ikeda & Katsuma, 200 from Borneo. Hexarthrius Hope, 1843 includes 15 species and many subspecies from Southeast Asia and Australasia. The Palaearctic and Oriental genus Lucanus Scopoli, 1763 variously includes up to a hundred species but many have now been transferred to other genera e.g. Noseolucanus Araya & Tanaka, 2000 and a more sensible estimate of the size of the genus is about 45 species,
- Nigidiini Benesh, 1960 Includes 7 genera from Southeast Asia and (the majority) Africa. The African Nigidius Macleay, 1819 includes more than 75 species while Novonigidius Dudich, 1923 includes 7 species from Southeast Asia and Borneo.
- Odontolabini Parry, 1870. Contains four genera of impressive species. Heterochthes Westwood, 1864 from Southeast Asia includes 2 species. Calcodes Westwood, 1843 from Sri Lanka and Southeast Asia includes 20 species. Neolucanus Thomson, 1862 includes 60 species and numerous subspecies from Southeast Asia, and the eastern Palaearctic and Southeast Asian Odontolabis Hope, 1842 includes 45 species and numerous subspecies.
- Pholidotini Kikuta, 1986 is monogeneric with 5 species from Brazil.
- Platycerini Oberthür, 1913 includes 4 genera. Platyceroides Benesh, 1946 is Nearctic while Platycerus Fourcroy, 1785 is Holarctic.
- Rhyssonotini Benesh, 1960 includes 2 genera and 10 species from Australia.
- Sclerostomini Benesh, 1955 is Neotropical and includes 5 genera. Metadorcinus Kriesche, 1922 includes 20 species from Brazil, the widespread Metadorcus Parry, 1870 includes 3 species, and both Pycnosiphorus Solier in Gay, 1851, with 5 subgenera, and Sclerostomus Burmeister, 1847, with 6 subgenera, are very speciose.

Description

The typical idea of the Stag Beetle is exemplified by our European species Lucanus cervus (Linnaeus, 1758), and more especially by the male with its large mandibles and long legs and antennae. A familiarity with this species will allow much of the world fauna to be recognized, albeit sometimes with disbelief, as sexual dimorphism becomes even more extreme in some tropical groups, and male dimorphic development is allometric i.e. the largest males have proportionally larger mandibles etc. while diminutive males of some species may resemble females. In some groups e.g. the Figulini Bermeister, 1847 the sexes are similar while in others sexual dimorphism takes another form e.g. in Sinodendron the males possess both clypeal and thoracic horns, and in most species the male head and/or pronotum is modified in some way, sometimes grossly so with various lateral parts expanded. Notwithstanding the unusual forms a general description of the family is as follows:

Heavily sclerotized and robust species, elongate and either weakly convex, sub-depressed or cylindrical. Most are black or brown, often with the elytra contrasting with the forebody, although in many tropical groups the elytra are strikingly patterned with red or yellow, and the Lampriminae and Lucaninae include some splendidly metallic green, red or, rarely, blue species. Most are glabrous and shiny but some groups e.g. the Aesanili have the elytra covered in scales or bristles or both. Size varies from 8 to about 100mm, among the smallest are in the Aesalinae and the largest among the tropical Lucaninae. Head prognathous, never deflexed, often with sexually dimorphic mandibles, the size of which is dictated by environmental as well as genetic factors; large and sometimes branched in males, and produced at least beyond the apex of the labrum in females. Eyes generally small and convex, generally round or oval and in many groups divided by a variously developed canthus. Labrum and clypeus fused to the frons, maxillary palps 4-segmented, labial palps 3-segmented. Antennae geniculate to straight, 10-segmented with a usually distinctly asymmetric 3 to 7 segmented club which cannot be ‘closed’, as they can in many other Scarabaeoidea groups, and so the individual segments are usually obvious, in some groups e.g. the Australian genus Lissapterus Deyrolle in Parry, 1870 (Lucaninae),the club is only slightly pectinate while in Ceratognathus Westwood, 1838 the club segments are very long, especially in the male, and articulated so that they can be moved, but they do not close into a compact club. In many Lucaninae the scape is characteristically long and curved, in Lamprina it is straight and clubbed, while in many groups e.g. Aesalinae, it is much shorter, barely longer than the second segment. The head is often sexually dimorphic being widely transverse and with various strongly-developed ridges or lateral expansions around the eyes or over the base of the mandibles in males, and normally developed in females. In Sinodendron the male clypeus is developed into a horn. The pronotum is very variable but generally smooth dorsally or raised longitudinally along the midline, the lateral margins smooth and curved or with various teeth or spines e.g. in Chiasognathus Stephens, 1831 with a strong and curved lateral tooth at the posterior angles. The pronotum is also frequently dimorphic being generally more transverse and robust in the male. The surface lacks horns or tubercles but in Sinodendron it is excavate anteriorly and has a small anteriorly-directed horn. The scutellum is always exposed and usually well-developed; triangular to rounded and sometimes convex or with surface features. Elytra entirely covering the abdomen, or with only a part of the pygidium exposed, smoothly curved to a continuously rounded or weakly truncate apex, shoulders well-developed and often toothed, the surface smooth in most groups although variously punctured and sculptured, sometimes very strongly so, in Syndesinae. Abdomen with 5 or 6 visible sternites and 8 spiracles situated in the pleural membrane. The hind-wings are usually well-developed with an M-Cu loop and 2 detached veins, although brachyptery and flightlessness are also widespread within the family. All coxae are transverse; the mesocoxae separated, the femora generally long and simple, the pro-tibiae toothed laterally and with a single long apical spur, meso- and meta-tibiae with ridges and 2 apical spurs which are not separated by the first tarsomere. Tarsi 5-segmented, the segments generally long and thickened towards the apex, in some species various tarsomeres are developed into spines. Claws simple, usually robust and

sharp. Empodium present in many groups, sometimes well-developed and extending beyond the claws, with 2 or more apical setae. Aedeagus with 2 symmetrical parameres and a median lobe; in Lucaninae the median lobe terminates in a ribbon-like internal sac. The mandibles of male stags are used in contests, generally over females but also over food such as decaying fruit or sap, and they may also be used in threatening postures against possible predators but in general they are not normally aggressive towards humans. Female mandibles although much smaller are also more powerful as they may be used to cut into wood prior to ovipositing.

Lucanid larvae are typically scarabaeiform; C-shaped, sub-cylindrical and strongly segmented, creamy white or yellowish although the heavily –sclerotized head is usually darker and in life the caudal end may be darkened by accumulated faeces. Antennae 3- or 4-segmented, the terminal segment usually diminutive. With the exception of the Platycerini and some Sclerostomini and Ceratognathini they lack ocelli. A frontoclypeal suture is present and the labrum is rounded or weakly lobed, the maxillary gala and lacinia are distinctly separate, and maxillary stridulatory teeth are present only in Platycerus. The maxillary palps are 4-segmented, the mandibles robust, elongate and asymmetrical. Abdominal segments 3-7 with 2 annuli, each with one or more rows of setae. Spiracles cribriform. Anal aperture longitudinal or Y-shaped, and surrounded by two lobes. Legs 4-segmented and usually small with well-developed claws. Lucanid larvae can stridulate although this is not always audible to humans, it is thought that stridulating communicates the presence of other larvae and may produce avoidance behaviour in some groups although those of some species, including Lucanus cervus, are often found in aggregations. Lucanid larvae are distinguished among the families of Scarabaeoidea by the vertical or Y-shaped anal aperture with its fleshy folds and the location of stridulatory files on the middle and hind coxae.

Dorcus parallopipedus larva

http://data.nhm.ac.uk/dataset/collection-specimens

Ecology

Lucanids are generally associated with decaying wood in both deciduous and coniferous wooded areas and some e.g. Lucanus cervus, are partly synanthropic. Adults of many species are nocturnal and are attracted to light, sap or decaying fruit etc. and some of the smaller species have been observed feeding on flowers. Most live long and secluded lives spent among decaying or fungoid trees and fallen timber, and many develop in underground roots or deep within dead or dying trunks, the life cycle of some taking up to eight years depending upon conditions of nutrition and temperature. Like most xylophagous insects the larvae use microorganisms to help digest material with high cellulose content, and female lucanids have recently been shown to possess mycangia (microbe-storage organs) containing microbes closely related to xylose-fermenting yeasts. After depositing eggs in bark crevices or among roots in the soil the female discharges these organisms in a secretion around them so initiating the wood-decay process for the larvae. The larvae generally develop slowly and pass through three instars, when fully grown they construct a pupal cell either in the wood or in soil adjacent to roots or fallen wood. The pupal stage usually lasts for a few weeks or a month but in temperate regions may take much longer; we have found Lucanus pupae in cells through the winter in West London. The pupa is exarate with all the adult features clearly visible and adult development is usually easy to follow. Freshly eclosed adults are pale and soft and remain in the pupal cell until they harden; this can be brief or may take several months depending on conditions.

As with saproxylic beetles in general the lucanids have been in decline in Europe for some decades, a situation that mirrors that of the wider world, add to this the efforts of collectors who seek out rare and endemic species and it seems the stags are having a hard time of it but there is perhaps no more sad a story than that of Apterocyclus Waterhouse, 1871, a genus of 5 species endemic to the Hawaiian island of Kauai, they are not protected and may already be extinct due to predation from introduced rats.