Colophon beetles are medium sized and body sizes range from about 14mm to 34mm, including the mandibles (jaws) and are dark brown in colour. They are heavy bodied like the dung beetles and also have toothed tibia (forelegs) adapted for digging. However, unlike dung beetles that belong to the family Scarabaeidae, Colophon belong to the related family, Lucanidae. Unlike most of the Lucanidae, Colophon are flightless but barchypterous (bear rudimentary/vestigial wings under the elytra or wing covers). Flightlessness.

As with other Lucanidae and most other members of the Scarabaeoidea super family, Colophon’s eyes are situated on the side of the flattened head and serve both the upper and lower body equally, very much like some aquatic beetles. This helps with all-round vision when in wet or submerged semi-wet conditions such as in wet dung, soft fruits etc. 

Females of the various species look very similar and although there are physical differences, the females of the species cannot be as easily differentiated as the males and it is the male morphology (body structure) which differentiates the species. In the males, the diagnostic characters are the genitalia, mandibles (jaws), front tibia (foreleg) and mentum (part of the mouthparts). The male mandibles are greatly enlarged while the females’ are small and non-diagnostic. Compare male and female morphology. It is thought that the males use the mandibles for combat in rivalry for females where they flip their rivals onto their backs.  

Distribution and habitat

Colophon beetles are of particular interest as each of the 17 species is isolated on a mountain range and in some cases, on a peak within the same range, separated by deep gorges or low lying areas. Consequently, the beetles are referred to as "mountain relics". This is because it is thought that they are surviving representatives of a cool, moist biome that once existed at a low altitude but which now only survives in mountain ranges at high altitudes. It is believed that as low lying plains dried out and became uninhabitable, so the species moved to higher altitudes. Over time, communities of the species became isolated on mountain ranges, separated by uninhabitable open plains or gorges. This resulted in speciation, where one or more species evolved into a series of different, although closely related, species, each restricted to its own mountain range, a translocated relic habitat that became their refuge or refugium.

One species group or lineage, the Pleisiomorphic lineage, is restricted to the Hottentots Holland, Steenbras, Hex River, Stellenbosch and Wellington Mountain ranges.

Another species group or lineage, the Apomorphic lineage species occur in the Table Mountain range, Swartberg, Meiringspoort, Swellendam and Heidelberg Mountains.

What is of particular interest is the species that occurs on the Table Mountain range. They are placed within  the Apomorphic lineage and yet it is separated from its two closest related species that occurs further east in the Swellendam Mountains, by a group of Pleisiomorphic species on the Hottentots Holland and Steenbrass Mountain ranges. Beetles have also been seen in the Cedarberg Mountains and it would be interesting to see to how this / these species is / are related to the others.

Questions regarding Colophon species’ relationships could be explained if more was known of the dispersion history. DNA analysis might also help clarify matters. Furthermore, DNA analysis would not only clarify relationships of currently known species but even establish if there are in fact as many species as documented. There is also anecdotal evidence that males mate with females of any species but as females of different species are difficult to differentiate, this would have to be investigated further.

Despite their geographic separation, all species are thought to persist in conditions that are similar to the original ancestral conditions so as  to maintain conditions conducive to existence. Colophon species have moved into very tight habitat niches in an effort to maintain those conditions. This is reflected in the altitudes at which they occur. In the Swartberg range, which is the driest habitat with the least cloud cover, the beetles occur at about 2000 m and are absent from lower levels. In the Langeberg Mountains they occur at lower levels, from 1300 m where conditions are optimal and at the other end of the scale, the species in the Table Mountain range, occurs at below 1000 m. By all accounts, Colophon beetles are active for a very short period in summer reducing that niche further. Perhaps in the past they were active throughout the year when conditions were ideal.

History

In ancient times the Karoo areas that are now arid, were once vast cool, temperate, marshy plains north and north east of the Western Cape mountain ranges. River systems such as the Berg, Breede, Gouritz, Olifants, Gamka and many others would have been extensive, and in some cases probably even interlinked lakes and floodplains and what we see of them today are mere trickles of their former splendour. Rainfall was high with regular flooding. These areas must have been prolifically covered with vast amounts of trees, plants and decaying material. In a habitat where food and mates were abundant, flight was either not a priority or an option if predators prevailed. Flightlessness.

With climate change and the associated aridification and increase in temperatures, rivers and moisture would have receded taking with them associated plants and animals. Some plants and associated animals would have receded downward with the moisture and some would have clung to corridors of moist and shaded gorges that might have provided access to moister, cooler climes above. Eventually, with complete aridification, all species that migrated downward and could not adapt, would have been doomed and those that clung to favoured habitats at higher altitudes, survived.

Perhaps conditions became too wet before they became too dry, resulting in the migrations upwards. Perhaps there was an extended event of massive flooding in which case everything would have been washed away and the flotsam of plants and animals deposited on higher ground. Mountains of plant debris would have been deposited and had the water persisted long enough, the verdant floodplains would have been destroyed as happens with present day dams. There would be no going back but instead to eke out a living on debris and new growth that was available on the raised foothills where species were deposited. Climate change and aridification at that stage would also have meant no going back downhill.

For animals that could not fly or move freely, competition among different species for food and mates in a reduced habitat would have been fierce and only those with distinct physical advantages would have survived to breed. Isolated from the original homogenous population by vast tracts of inhospitable lowlands - or water - animals and insects with restricted movement would have followed the food source and if that moved up the slopes to cooler, moister climes, so would they.

Colophon is considered to be a link to Gondwanaland but according to specialists, there is no evolutionary link between Colophon and old-world African Lucanidae. Not only does Colophon not seem to have derived from them but neither does the old-world Africa stock seem to have been derived from Colophon. Furthermore, it is also difficult to establish Colophon's relationship with other members of the Lucanidae  family. Specialists agree that Colophon does not belong to either of the southern hemisphere subfamilies but is better placed with the Lucaninae. This is a bit of a mystery especially when specialists seem to conclude that all our primordial fauna are southern in origin.

Barnard (1929) also studied other high-mountain fauna and suggested that all high mountain flora and fauna originate from a distinct biome. One such animal is the fresh-water Crustacean, Phreatoicus which is also restricted to high altitudes. However, Barnard was puzzled by the fact that Colophon occurs as different species in the various localities while Phreatoicus remains unchanged. It is interesting to speculate that this would be expected had extended flooding been a factor that isolated Colophon because Phreatoicus would not have been isolated. However, Barnard (1929) concedes the need for the intervention of the geologist to establish the age of the rock formations of the gorges that separate species and this would help to establish the age of Colophon.

Whatever the event that caused the speciation, survival resulted from a balance between the magnitude of the environmental differences before and after the event and the adaptive capacity of the surviving populations. The genetic makeup that determined the adaptive characters of survival became fixed in the ‘shipwrecked’ survivors and perpetuated in subsequent generations.  

Biology

Colophon beetles are reported to be rarely seen and very little is known of their life histories. Most sightings take place from November to January. It is generally believed that it is a few privileged mountain climbers who are lucky enough to see them and then they might only see them if enough time is spent in the mountains. Conditions also need to be ideal and these can only be described as less than ideal for the average recreational mountaineer. It has also been documented that Colophon's activities are restricted to early mornings and late afternoons, even after sunset, in cool misty, foggy and even rainy conditions. However, while there is agreement regarding the months of activity, there are contradictions regarding  conditions under which they are active. They are definitely diurnal and not nocturnal as Barnard initially thought. They have been sighted at any time of day, even in midday heat and in some cases in large numbers to the extent where "hikers trample them on paths".

Larvae of the Lucanidae are generally internal wood and decaying wood feeders so the family is essentially associated with forests. However, this is not the case with Colophon as there have been no trees or woody shrubs in any of the areas where live specimens have been collected. The larvae are probably not borers at all and might feed on roots instead. Barnard noted that all specimens that he found were in Erica-Restio habitats and he fancied the Restionaceae option. However, some studies were done (Scholtz & Endrödy-Younga, 1994) on a few larvae under laboratory conditions where they were observed to feed on humus-rich soil that was sampled with the animals.

Barnard’s observations are confirmed by reports that beetles are reported to occur on slopes near drainage areas where restios occur, so beetles probably feed on root debris and detritus nutrients in the soil. They have also been found under rocks. It would seem that eggs are laid in the soil and the larvae remain there for three to four years. Not too much is known about the larvae as they are difficult to find and only the larva of one species has been described. Larvae have been bred out under laboratory conditions by being placed under a stone with damp soil and dung and kept cool and damp. The adult emerged after 2 years.

One wonders if their food source is still what it was in their original ancestral habitats or were they also borers of wood and have merely adapted to something else as conditions changed. Scholtz, Harrison and Grebennikov (2004) cite Pachysoma (all species) as an example of such a change where they abandoned dung-rolling habits in wet habitat and reverted to what is thought to have been ancestral habits of collecting and assembling dry dung as conditions dried out. This is deposited in pre-excavated burrows where eggs are laid and larvae move freely in tunnels.   Some present day Scarabaeidae beetles are also known to have changed their habits due to pressure or choice and have adapted to modern conditions such as from herbivore dung to domestic dog faeces (Onthophagus ebenus) and there’s an anecdotal record where there was a shift from dung to golf course grass (Bolbocaffer peringueyi). Fossil records of 5 million years ago from the West Coast Fossil Park and Karoo areas indicate moist riverine habitats with trees and palm trees (as well as bears and sabre-toothed cats). Being feeders of rotting vegetation probably pre-adapted them to survive and rotting fibre plants such as palms and restios were/are similar enough for a desperate Colophon.

 Conservation

As far back as 1929, Dr Barnard cited veld fires as a threat to Colophon and that threat is now more alarming. Since then human encroachment results in all too frequent fires that rage in the hot summer months. However, Colophon has survived thus far even with the added threat of climate change. Being soil dwelling insects, they have probably evolved ways of avoiding fire.

While they might have evolved ways of surviving intermittent fires, they are neither equipped to survive the greed of humans who collect every available adult for personal enrichment nor the modern conveniences of humans such as 4X4 vehicles and concrete platforms for cell phone masts. Furthermore, the effect of the radiation from  repeater masts might also have a negative impact.

Being flightless precludes Colophon beetles from readily escaping fire and and collectors as other insects do. Neither can they seek out and colonise better habitats when theirs becomes too degraded for survival. This, and the fact that so little is known of their biology, places their long-term survival at great risk. It is not known what comprises an ideal Colophon habitat. It is not known how many eggs are laid by a single adult. It is not known what proportion of adults emerge during ideal times. If the emergence of an entire adult population coincides with a visit by collectors, an entire adult breeding population could be destroyed especially if collection precedes egg laying. It is also not known how long the eggs take to emerge or how long the larvae remain underground although it is thought to be 3 to 4 years. It is not known if Colophon might be similar to some scarabs where the presence of the female is needed for the emergence of the brood although this notion is dispelled by the success under laboratory conditions described above.

As a result of commercial pressure, Colophon beetles have been placed on CITES Schedule II (CITES, Convention on International Trade in Endangered Species - in wild flora and fauna, http://www.cites.org).  This means that no trade, exchange or sale of Colophon species is allowed. Limited reference specimens may only be collected for scientific purposes with the appropriate permit issued by the Department of Western Cape Nature Conservation.

All Colophon species are listed as endangered and Colophon primosi as critically endangered.

Local governments have increased pressure on poachers. In January 2004, a group of German collectors was arrested near Ceres and a few hundred beetle specimens of about 16 beetle species were confiscated and these include  Colophon. They were arrested, prosecuted and fined R125 000.00. At present, the main threat to this genus is over-collecting by European and Japanese traders.

Members of the public are requested to be vigilant regarding exploitation of, not only threatened Colophon species, but all species associated with the sensitive Cape Floral Biome system. Cape Nature conservation can be contacted with queries or to report any contraventions.

Publications

• BARNARD, K. H. 1929. A study of the genus Colophon Gray. Transactions of the Royal Society of South Africa 18: 163 –182. 

• BARNARD, K. H. 1932a. The Colophon. Journal of the Mountain Club of South Africa 34: 19-22. 

• BARNARD, K. H. 1932b. The rediscovery of Colophon thunbergi Westw. with descriptions of further species of the genus. Stylops 1: 169-174.

• BARTOLOZZI. L. & WERNER. K. 2004. Illustrated catalogue of the Lucanidae from Africa and Madagascar. Taita Publishers, Czech Republic. Pages  – 189.

• BARTOLOZZI, L. 2005. Description of two new stag beetle species from South Africa (Coleoptera: Lucanidae). African Entomology 13(2): 347 – 352.

• ENDRÖDY-YOUNGA, S. 1988. Evidence for the low-altitude origin of the Cape Mountain Biome derived from the systematic revision of the genus Colophon Gray (Coleoptera, Lucanidae). Annals of the South African Museum 96(9) 359 – 424. 

• GRAY. G. R. 1832. New species of insects of all orders. In: Griffith, E. The animal kingdom arranged in conformity with its organization by the Baron Cuvier 14. London: Whittaker. 

• MIZUKAMI, T. 1996. A new species and a new subspecies of the Genus Colophon from the Republic of South  Africa (Coleoptera, Lucanidae). Gekkan-Mushi 304: 22-25..

• SCHOLTZ, C. H. 2000. Evolution of flighlessness in Scaraboidea, (Coleoptera). Deutsche Entomolgische Zeitschrift. 47(1): 5 – 28.  

• SCHOLTZ, C. H. & ENDRÖDY-YOUNGA, S. 1994. Systematic position of Colophon Gray (Coleoptera: Lucanidae), based on larval characters. African Entomology, 2(1): 13 - 20.

• SCHOLTZ, C. H., HARRISON, J. du G. & GREBENNIKOV, V. V.  2004 Dung beetle (Scarabaeus (Pachysoma)) biology and immature stages: reversal to ancestral states under desert conditions (Coleoptera: Scarabaeidae)? Biological Journal of the Linnean Society (83) 453 – 460.

• WESTWOOD, J. O. 1855. Descriptions of some new species of exotic Lucanidae. Transactions of the Entomological Society of London 3: 197-221.

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• Species groups
• Morphology
• Distribution and habitat
• History
• Biology
• Conservation
• Publications