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Notes on the biology of ambrosia beetles of the genus Trachyostus Schedl (Coleoptera: Platypodidae) in West Africa

Published online by Cambridge University Press:  10 July 2009

Hywell Roberts
Hywell Roberts
Affiliation:
Federal Department of Forest Research, Ibadan, Nigeria
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Extract

The biology of three West African ambrosia beetles, Trachyostus aterrimus (Schauf.), T. ghanaensis Schedi and T. schaufussi schaufussi (Strohm.) is described on the basis of studies made in China and Nigeria, and notes are given on the six other species and subspecies of Trachyostus that have been taken in West Africa.

All species of Trachyostus are confined to forest areas in West Africa. some of the species extend into montane and swamp forest, but the genus is most abundant in lowland rain forest. It is suggested that susceptibility to desiccation of the young larvae and of the ambrosia fungus is the principal factor in limiting Trachyostus species to forest areas. Two species, T. ghanaensis and T. interstitialis Schedl, are confined to the forests between Sierra Leone and Ghana, but the remaining species are found throughout the lowland forest of west Africa.

Host selection by species of Trachyostus depends mainly on the taxonomic status of the host, the condition of the tree, and the time of year. The genus as a whole is considered very selective. T. ghanaesis attacks living trees of only one host species, selecting individual trees and favouring the most vigorous. All other species of Trachyostus normally attack felled trees of a wide range of host species, but show preferences for those of a small number of plant genera. Attack on living trees by species other than T, ghanaensis occurs in the dry season. It is suggested that T. ghanaensis is sensitive to subtle changes in tree condition, while the remaining species require a more drastic change before attacking such trees.

The process of nest initiation and establishment is described for ome species. Species of Trachyostus differ from other tropical Platypodids in that the length of time elapsing between nest initiation and the emergence of the first young adults is exceptionally long. This is thought to be mainly due to the ambrosia fungus requiring a long time to establish itself on the gallery walls of the nest.

All species of Trachyostus are active in daylight hours. Emergence of young adults from the nest occurs only in daylight and is dependent on a drying atmosphere. Falling light intensities probably contribute towards ending emergence in the late afternoon. The thresholds of humidity and illumination for emergence of T. schaufussi schaufussi appear to be higher than those of T. aterrimus.

Nests of T. aterrrimus and T. schaufussi schaufussi remain functional for about nine months, but those of T. ghanaensis can still be active after four years. The protracted nest duration of T. ghanaensis is apparently a consequence of the habit of this species of attacking living host trees in which the rate of development seems to be slowed down. Only a small proportion of the nests initiated by species of Trachyostus are successful. In T, ghanaensis this high failure rate is attributable to failure of the ambbrosia fungus, but in the other species insect nest-associates and predators are apparently the main causes.

The habits and life-history of T. ghanacnsis can only be compared with those of one other Platypodid, Dendroplatypus impar (Schedl), a Malaysian species. Both species attack only living trees, and show a high degree of host selection. The intensity of attack on the host tree by these species is very low, and the life-cycle of each seems to take a long time for completion.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 58 , Issue 2 , November 1968 , pp. 325 - 352
Copyright
Copyright © Cambridge University Press 1968

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References

Baker, J. M. (1956). Investigations on the oak pinhole borer, Platypus cylindrus Fab.—Rec. Conv. Br. Wood Pres. Ass. [1956] pp. 92–111.Google Scholar
Baker, J. M. (1965). Aspects of the life history of the ambrosia beetle Platypus cylindrus Fab.—Proc. XIIth int. Congr. Ent. pp. 694–696.Google Scholar
Browne, F. G. (1961a). The biology of Malayan Scolytidae and Platypodidae.—Malay. Forest Rec. no. 22, 255 pp.Google Scholar
Browne, F. G. (1961b). Preliminary observations on Doliopygus dubius (Samps.) (Coleoptera: Platypodidae).—Fourth Rep. W. Afr. Timb. Borer Res. Unit pp. 15–30.Google Scholar
Browne, F. G. (1962a). The emergence, flight and mating behaviour of Doliopygus contradti (Strohm.), (Coleoptera: Platypodidae).—Fifth Rep. W. Afr. Timb. Borer Res. Unit 1961–1962 pp. 21–27.Google Scholar
Browne, F. G. (1962b). Sosylus spectabilis Grouvelle (Coleoptera: Colydiidae), a predator and parasite of African ambrosia beetles.—Fifth Rep. W. Afr. Timb. Borer Res. Unit 1961–1962 pp. 91–96.Google Scholar
Browne, F. G. (1963). Notes on the habits and distribution of some Ghanaian bark beetles and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae).—Bull. ent. Res. 54 pp. 229–266.CrossRefGoogle Scholar
Browne, F. G. (1965). Types of ambrosia beetle attack on living trees in tropical forests.—Proc. XIIth int. Congr. Ent. p. 680.Google Scholar
Cachan, P. (1957). Les Scolytoidea mycétophages des forêts de Basse Côted’Ivoire. Problèmes biologiques et écologiques.—Revue Path. vég. Ent. agric. 36 pp. 1–126.Google Scholar
Carcasson, R. H. (1964). A preliminary survey of the zoogeography of African butterflies.—E. Afr. Wildl. J. 2 pp. 122–157.Google Scholar
Chapman, J. A. (1962). Field studies on attack flight and log selection by the ambrosia beetle Trypodendron lineatum (Oliv.) (Coleoptera: Scolytidae).—Can. Ent. 94 pp. 74–92.CrossRefGoogle Scholar
Chapman, J. A. (1966). The effect of attack by the ambrosia beetle Trypodendron lineatum (Olivier) on log attractiveness.—Can. Ent. 98 pp. 50–59.CrossRefGoogle Scholar
Graham, K. (1961). Air-swallowing: a mechanism in photic reversal of the beetle Trypodendron.—Nature, Lond. 191 no. 4787 pp. 519–520.Google Scholar
Jones, T. (1959). Ambrosia beetles (Scolytoidea): their biology and control in West Africa.—Tech. Bull. W. Afr. Timb. Borer Res. Unit no. 2, 14 pp.Google Scholar
Jordan, A. M. (1962). The ecology of the fusca group of tsetse flies (Glossina) in southern Nigeria.—Bull. ent. Res. 53 pp. 355–385.Google Scholar
Jover, H. (1952). Note préliminaire sur la biologie des Platypodidae de BasseCôte d’Ivoire.—Revue Path. vég. Ent. agric. 31 pp. 73–81.Google Scholar
Keay, R. W. J. (1959). Vegetation map of Africa south of the Tropic of Cancer.—24 pp. London, Oxford Univ. Pr.Google Scholar
Nash, T. A. M. (1948). Tsetse flies in British West Africa.—77 pp. London, Colon. Off.Google Scholar
Pitman, G. B., Renwickj, A. A. & VitÉ, J. P. (1966). Studies on the pheromone of lps confusus (Le Conte). IV. Isolation of the attractive substance by gas-liquid chromatography.—Contr. Boyce Thompson Inst. Pl. Res. 23 pp. 243–250.Google Scholar
Roberts, H. (1960). Trachyostus ghanaensis Schedl, (Col., Platypodidae) an ambrosia beetle attacking wawa, Triplochiton scleroxylon K. Schum.—Tech. Bull. W. Afr. Timb. Borer Res. Unit no. 3, 17 pp.Google Scholar
Roberts, H. (1961). The adult anatomy of Trachyostus ghanaensis Schedl (Platypodidae), a W. African beetle, and its relationship to changes in adult behaviour.—Fourth Rep. W. Afr. Timb. Borer Res. Unit pp. 31–38.Google Scholar
Roberts, H. (1962). A description of the developmental stages of Trachyostus aterrimus (Schauf.), a West African Platypodid, and some remarks on its biology.—Fifth Rep. W. Afr. Timb. Borer Res. Unit 1961–1962 pp. 29–46.Google Scholar
Roberts, H. (1965). Further new Platypodidae (Coleoptera) from Nigeria, West Africa.—Ann. Mag. nat. Hist. (13) 8 pp. 219–228.CrossRefGoogle Scholar
Rudinsky, J. A. & Datermang, E. (1964). Response of the ambrosia beetle Trypodendron lineatum (Oliv.) to a female-produced pheromone.—Z. angew. Ent. 54 pp. 300–303.Google Scholar
Schaufuss, C. Borkenkäfer-Studien. I.—Berl. ent. Z. 42 (1897) pp. 101–112.CrossRefGoogle Scholar
Schedl, K. E. (1960). A new Platypodid (Coleoptera: Scolytoidea) from Triplochiton scleroxylon.—Ann. Mag. nat. Hist. (13) 2 (1959) pp. 235–236.Google Scholar
Schedl, K. E. (1962). On some African bark and timber beetles.—Fifth Rep. W. Afr. Timb. Borer Res. Unit 1961–1962 pp. 57–74.Google Scholar
Schedl, K. [1965]. Scolytidae und Platypodidae Afrikas, Band III.—Revta. ent. Mocamb. 5 (1962) pp. 597–1352.Google Scholar
Strohmeyer, H. (1911). Die biologische Bedeutung sekundärer Geschlechtscharaktere am Kopfe weiblicher Platypodiden.—Ent. Bl. 7 pp. 103–107.Google Scholar
Strohmeyer, H. (1913). Neue Platypodiden.—Ent. Bl. 9 pp. 160–165.Google Scholar
Thompson, G. H. (1963). Forest Coleoptera of Ghana. Biological notes and host trees.—Oxf. For. Mem. no. 24, 78 pp.Google Scholar
VitÉ, J. P. & Gara, R. I. (1962). Volatile attractants from Ponderosa pine attacked by bark beetles.—Contr. Boyce Thompson Inst. Pl. Res. 21 pp. 251–273.Google Scholar
Webb, W. E. & Jones, T. (1957). [First] Report of the West African Timber Borer Research Unit 1953–55.—37 pp. London, Crown Agents.Google Scholar