Research on the Biology and Taxonomy of Ants, and their role as Vectors of Cocoa Black Pod Disease.

My plant pathologist colleagues (M.J. Griffin and A.C. Maddison) and I made exhaustive studies of the seasonal epidemic of cocoa black pod caused by species of the fungal Genus Phytophthora, which led to a new comprehension of this major, and often devastating, disease. My particular role, assisted by S.F. Adedoyin, centred on insect vectors of the disease, especially on the many species of ant which could be found on and around cocoa trees, and our work can be described most easily from three separate but inter-woven aspects.

Ants as vectors of black-pod disease. Although there was some prior evidence, implicating insects in the outbreak and spread of the disease, this was limited and our ant-black pod studies are without parallel in the depth and intensity of the observations. For example, the largest of the studies of the epidemic (led by Dr. Griffin and myself) involved daily examination of each of 1139 trees from March to September, with twice-weekly recording of ant-tents and the tent-building species. The results demonstrated conclusively that up to 23% of all initiator infections (or primary source infections) could be associated with ant activity, particularly the use of soil to build tents (covers) over species of sap-exuding Homoptera (aphids, stictococcids and pseudococcids).

Ant ecology. The number of ant species found to construct soil tents, however, was found to be quite small and, as with the many other ant species, their distribution and abundance was extremely variable. This made it essential to evaluate the impact of inter-species competition and parallel, detailed investigations were made of the biology and distribution of the whole spectrum of ant species found in plantations. At CRIN alone, we (myself assisted by Mr. Adedoyin) collected 130 species of ant; 56 species were recorded in intensive studies with 1426 possible occurrences on cocoa; rapid surveys were made of 4898 other cocoa trees, of other tree crops (kola, cashew, oil palm, coffee and plantain) and of natural forest trees. The information greatly expanded knowledge of the ant mosaic, especially on the three-dimensional aspects of the ant populations in cocoa farms, and showed that the Nigerian situation was significantly different from that known from Ghana. To test the validity of conclusions reached at CRIN, we then made a large-scale survey of 50 trees on each of 76 cocoa farms scattered throughout western Nigeria. A principal components analysis was used in interpreting the results. Nothing like this had been done elsewhere and our findings underlined the great complexity of the interactions of dominants and co-dominants, the essential need to consider the cocoa canopy, etc., when proposing "manipulation" of the dominants, and the importance of the tending of mealy-bugs, aphids, etc., by tent-building ants.

Ant taxonomy. The difficulty in sorting out the very numerous species of ants necessitated my spending much time on taxonomy and this led me on to produce fully-illustrated field guides to the forest-zone ants. I personally made some 500 drawings of the worker castes of around 200 species. The guides include observations of the biology of many of the species and a summary conspectus completed the presentation. I have now reviewd the whole of the above and wider knowledge on the Ants of West Africa, with a grant from The Royal Entomological Society, the whole is published on this WWW University of Nottingham site.

PUBLICATIONS -
Taylor, B. (1975c) The role of an entomologist in the International Black Pod Research Project. pp 52-55. In Proceedings of the 4th Conference of West African Cocoa Entomologists, (Legon, Ghana), 1974.
Taylor, B. (1976-1980) Ants of the Nigerian Forest Zone (Hymenoptera: Formicidae). Parts I-V. Cocoa Research Institute of Nigeria Research Bulletin, 4-8. Total 260 pp.
Taylor, B. (1977b) The ant mosaic on cocoa and other tree crops in Western Nigeria. Ecological Entomology, 2, 245-255.
Taylor, B. & Adedoyin, S.F. (1978) The abundance and inter-specific relations of common ant species (Hymenoptera: Formicidae) on cocoa farms in Western Nigeria. Bulletin of Entomological Research, 68, 105-121.
Griffin, M.J., Idowu, O.L., Maddison, A.C., Taylor, B. & Ward, M.R. (1981) Sources of infection. Chapter 6, pp. 75-95. In Epidemiology of Phytophthora on Cocoa in Nigeria. CMI Phytopathological Paper No. 25.
Taylor, B. & Griffin, M.J. (1981) The role and relative importance of different ant species in the dissemination of black pod disease of cocoa. Chapter 8, pp. 114-131. In Epidemiology of Phytophthora on Cocoa in Nigeria. CMI Phytopathological Paper No. 25.
Taylor, B. & Adedoyin, S.F. (1981) A general view of ant biology in relation to cocoa. Chapter 9, pp. 132-144. In Epidemiology of Phytophthora on Cocoa in Nigeria. CMI Phytopathological Paper No. 25.
Taylor, B. (1981) Ant species recorded on cocoa in Western Nigeria. Appendix 2, pp. 182-184. In Epidemiology of Phytophthora on Cocoa in Nigeria. CMI Phytopathological Paper No. 25.
Taylor, B. (1995a) Book Review of: Identification Guide to the Ant Genera of the World, by Barry Bolton (Harvard University Press, 1994, 222 pp). Antenna, 19, 85-87.
Taylor, B. (1998) Book Review of: Journey to the ants: a story of scientific exploration by Bert Holldobler and Edward O. Wilson (Harvard University Press, 1994, 228 pp). Antenna, 22, 39-40.
Taylor, B. (1998) The Ants of West Africa. WWW Monograph opened April 1998 and now incorporated in the Ants of sub-Saharan Africa

INTERNATIONAL RECOGNITION

In addition to the citations listed below; more recent taxonomy (notably by B. Bolton of the Natural History Museum) has verified my separation of species and shown that my collections included the holotypes of Tetramorium granulatum, Cataulacus taylori and Axinidris kinoin; plus paratypes of three species; and many recognised first records for Nigeria. The late Prof. P.H. Gregory FRS, of Rothamsted and external advisor to the Black Pod Project, wrote to me in 1978 - "Thanks indeed for the very interesting reprint of your paper on the Nigerian ant surveys...I congratulate you and your assistants on the results". C.A. Collingwood FRES, of the Leeds City Museum and an expert on ant taxonomy, wrote in 1980 - "Many thanks indeed for copies of the handbooks to identification. I congratulate you on a very good job well done under the circumstances. You must have been very industrious to have produced all this in the limited time at your disposal....There is no doubt that your keys will provide a good reference for some time to come and a stimulus to other workers to fill in the gaps in due course." Prof. M.J. Way also has written (1993) - In particular, as you say, Chapter 8 (Taylor & Griffin 1981) is very comprehensive and I think is an outstanding contribution".

Citations
Taylor 1977a
Leston, D. 1978. Annals of the Entomological Society of America, 71, 649.
Lynch, J.F. 1980. Ecological Entomology, 5, 353.
Bigger, M. 1981. Bulletin of Entomological Research, 71, 107.
Jutsum, A.R. 1981. J. of Applied Ecology, 18, 187.
Hölldobler, B. 1983. Biotropica, 15, 241.
Apperson, C.S. 1984. Florida Entomologist, 67, 383.
Jackson, D.A. 1984. Oecologia, 62, 318.
Adams, E.S. 1990. Biotropica, 22, 200.
Déjean, A. 1991. Entomophaga, 36, 29.
Majer, J.D. 1991. Biotropica, 23, 173.
Déjean, A. 1991. Acta Oecologica, 12, 471.
Wood, B.J. 1992. FAO Plant Production & Protection Paper, 112, 45.
Bigger, M. 1993. Bulletin of Entomological Research, 83, 475.
Majer, J.D. 1993. In Hymenoptera & Biodiversity. Eds. J. La Salle & I.D. Gauld, CABI, Wallingford, 115-141.
Byrne, M.M. 1994. Biotropica, 26, 61.
Davidson, D.W. 1997. Biological J. of the Linnean Society, 61, 153-181.

Taylor & Adedoyin 1978
Bigger, M. 1981. Bulletin of Entomological Research, 71, 107.
Brian, M.V. 1983. Social Insects, Cambridge Univ. Press.
Levings, S.C. 1983. Ecological Monograph, 53,
Jackson, D.A. 1984. Oecologia, 62, 318.
Lokkers, C. 1986. Australian J. of Zoology, 34, 683.
Wheeler, D.E. 1986. J. Kansas Entomological Society, 59, 542.
Déjean, A. 1991. Acta Oecologica, 12, 471.
Bigger, M. 1993. Bulletin of Entomological Research, 83, 475.
Davidson, D.W. 1997. Biological J. of the Linnean Society, 61, 153-181.

Griffin et al. 1981
McGregor, A.J. 1985. Annals of Applied Biology, 107, 271.
Pereira, J.L. 1992. FAO Plant Production & Protection Paper, 112, 13.
Holderness, M. 1992. FAO Plant Production & Protection Paper, 112, 171.

Taylor & Griffin 1981
McGregor, A.J. 1985. Annals of Applied Biology, 107, 271.
Webber, J.F. & Gibbs, J.N. 1987. In Insect-Fungus Interactions. Eds. P.M. Hammond & J.F. Webber, Academic Press, London, 161-193.
Holderness, M. 1992. FAO Plant Production & Protection Paper, 112, 171.

Gregory, P.H. (ed.) 1981 - Epidemiology of Phytophthora on Cocoa in Nigeria. CMI Phytopathological Paper No. 25. (the full volume)
Waller, J.M. 1984. In Plant Diseases, Infection, Damage & Loss. Ed. R.K.S. Wood, Blackwell, Oxford.
Ho. H.H. 1987. Mycotaxon, 29, 207.
Evans, H.C. 1987. Outlook on Agriculture, 16, 35.
Keane, P.J. 1992. FAO Plant Production & Protection Paper, 112, 1.

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©1998 - Brian Taylor CBiol FSBiol FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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