Abstract
Age-specific effects of invertebrate pathogens on their hosts can greatly influence the population dynamics in such interactions. Explanations for such differences are usually sought within differing intrinsic susceptibilities of the host life stages but we present data which indicate that host size, behaviour and life history may be the overriding factors determining age-specific effects of a fungal pathogen, Neozygites floridana (Entomophthorales: Neozygitaceae) on spider mites (Mononychellus tanajoa Bondar, Acari: Tetranychidae). Epizootics of N. floridana in spider mites are characterised by much greater relative mortality of adult females compared with other life stages (ca. 99%), despite similar physiological susceptibilities. We present empirical data that demonstrate encounter rates of mites with N. floridana increasing with life stage during an epizootic on cassava in northeastern Brazil. Estimates of the size, walking speeds and patterns, and life history of different life stages (and adult sexes) were used to calculate expected relative encounter rates which were found not to be different from the observed values (although not testable for larvae). This helps explain the different apparent susceptibility of host life stages in the field. Given the low ecological susceptibility of younger life stages to this pathogen, we predict that the interaction time between host and pathogen, determined by climatic conditions, will be critical in determining the degree of host population control in an epizootic. We further hypothesise that such variation in ecological susceptibility to pathogens can generate selection pressures on basic host traits, contributing to the sessile nature of many microarthropods.
Similar content being viewed by others
References
Briggs, C.J. and Godfray, H.C.J. 1995. The dynamics of insect-pathogen interactions in stagestructured populations. Am. Nat. 145: 854-887.
Briggs, C.J. and Godfray, H.C.J. 1996. The dynamics of insect-pathogen interactions in seasonal environments. Theoret. Popul. Biol. 50: 149-177.
Carner, G.R. and Canerday, T.D. 1970. Entomophthora sp. as a factor in the regulation of the two spotted spider mite on cotton. J. Econ. Entomol. 63: 638-640.
Elliot, S.L., de Moraes, G.J., Delalibera Jr., I., da Silva, C.A.D., Tamai, M.A. and Mumford, J.D. 2000. Potential of the mite-pathogenic fungus Neozygites floridana (Entomophthorales: Neozygitaceae) for control of the cassava green mite Mononychellus tanajoa (Acari: Tetranychidae). Bull. Entomol. Res. 90: 191-200.
Elliot, S.L., de Moraes, G.J. and Mumford, J.D. 2002a. Importance of ambient saturation deficits in an epizootic of the fungus Neozygites floridana in cassava green mite (Mononychellus tanajoa). Exp. Appl. Acarol. (in press).
Elliot, S.L., de Moraes, G.J. and Mumford, J.D. 2002b. The initiation of epizootics of the mite-pathogenic fungus Neozygites floridana (Entomophthorales: Neozygitaceae) in the cassava green mite (Acari: Tetranychidae) in north-eastern Brazil (in preparation).
Elliot, S.L., Mumford, J.D. and de Moraes, G.J. 2002c. The role of resting spores in the survival of the mite-pathogenic fungus Neozygites floridana from Mononychellus tanajoa during dry periods in Brazil. J. Invertebrate Pathol. (in press).
Godfray, H.C.J. and Briggs, C.J. 1999. The dynamics of insect-pathogen interactions. In: Theoretical Approaches to Biological Control, B.A. Hawkins and H.V. Cornell, (eds), pp. 307-326. Cambridge University Press, Cambridge.
Helle,W. and Sabelis, M.W. 1985. Spider Mites, their Biology, Natural Enemies and Control, Vol. 1A. Elsevier, Amsterdam.
Hountondji, F.C.C., Lomer, C.J., Hanna, R., Cherry, A.J. and Dara, S.K. 2002. Field evaluation of Brazilian isolates of Neozygites floridana (Entomophthorales: Neozygitaceae) for the microbial control of cassava green mite in Benin, West Africa. Biocontrol Sci. Techn. 12: 361-370.
Jepson, P.C., Chaudhry, A.G., Salt, D.W., Ford, M.G., Efe, E. and Chowdhury, A.B.M.N.U. 1990. A reductionist approach towards short-term hazard analysis for terrestrial invertebrates exposed to pesticides. Funct. Ecol. 4: 339-347.
Moerbeek, M. and van den Bosch, F. 1997. Insect-pathogen dynamics: stage-specific susceptibility and insect density dependence. Math. Biosci. 141: 115-148.
Oduor, G.I. 1995. Abiotic factors and the epizootiology of Neozygites cf. floridana, a fungus pathogenic to the cassava green mite. PhD Thesis, University of Amsterdam, The Netherlands.
Oduor, G.I., de Moraes, G.J., Yaninek, J.S. and van der Geest L.P.S. 1995a. Effect of temperature, humidity and photoperiod on mortality of Mononychellus tanajoa (Acari: Tetranychidae) infected by Neozygites cf. floridana (Zygomycetes: Entomophthorales). Exp. Appl. Acarol. 19: 571-579.
Oduor, G.I., Yaninek, J.S., van der Geest, L.P.S. and de Moraes, G.J. 1995b. Survival of Neozygites cf. floridana (Zygomycetes: Entomophthorales) in mummified cassava green mites and the viability of its primary conidia. Exp. Appl. Acarol. 19: 479-488.
Oduor, G.I., de Moraes, G.J., van der Geest, L.P.S. and Yaninek, J.S. 1996a. Production and germination of primary conidia of Neozygites floridana (Zygomycetes: Entomophthorales) under constant temperature, humidity, and light conditions. J. Invertebrate Pathol. 68: 213-222.
Oduor, G.I., Yaninek, J.S., van der Geest, L.P.S. and de Moraes, G.J. 1996b. Germination and viability of capilliconidia of Neozygites floridana (Zygomycetes: Entomophthorales) under constant temperature, humidity, and light conditions. J. Invertebrate Pathol. 67: 267-278.
Oduor, G.I., Yaninek, J.S., de Moraes, G.J. and van der Geest, L.P.S. 1997a. The effect of pathogen dosage on the pathogenicity of Neozygites floridana (Zygomycetes: Entomophthorales) to Mononychellus tanajoa (Acari: Tetranychidae). J. Invertebrate Pathol. 70: 127-130.
Oduor, G.I., Sabelis,M.W., Lingeman, R., de Moraes, G.J. and Yaninek, J.S. 1997b. Modelling fungal (Neozygites cf. floridana) epizootics in local populations of cassava green mites (Mononychellus tanajoa). Exp. Appl. Acarol. 21: 485-506.
Onstad, D.W. and Carruthers, R.I. 1990. Epizootiological models of insect diseases. Annu. Rev. Entomol. 35: 399-419.
Ridsdill-Smith, T.J. and Annells, A.J. 1997. Seasonal occurrence and abundance of redlegged earth mite Halotydeus destructor (Acari: Pentheleidae) in annual pastures of southwestern Australia. Bull. Entomol. Res. 87: 413-423.
Sabelis, M.W. 1981. Biological control of two-spotted spider mites using phytoseiid predators. Part I. Modelling the predator-prey interaction at the individual level. Wageningen Agricultural University Thesis.
Salt, D.W. and Ford, M.G. 1984. The kinetics of insecticide action. Part III. The use of stochastic modelling to investigate the pickup of insecticides from ULV-treated surfaces by larvae of Spodoptera littoralis. Pesticide Sci. 15: 382-410.
Susilo, F.X., Nordin, G.L. and Brown, G.C. 1994. Age-specific and inter-sexual susceptibility of twospotted spider mite, Tetranychus urticae Koch, to Neozygites floridana Weiser and Muma. J. Kansas Entomol. Soc. 67: 293-296.
van der Geest, L.P.S., Elliot, S.L., Breeuwer, J.A.J. and Beerling, E.A.M. 2000. Pathogens of mites. Exp. Appl. Acarol. 24: 497-560.
Yaninek, J.S., Gutierrez, A.P. and Herren, H.R. 1989. Dynamics of Mononychellus tanajoa (Acari: Tetranychidae) in Africa: experimental evidence of temperature and host plant effects on population growth rates. Environ. Entomol. 18: 633-640.
Yaninek, J.S., Saizonou, S., Onzo, A., Zannou, I. and Gnanvossou, D. 1996. Seasonal and habitat variability in the fungal pathogens, Neozygites cf. floridana and Hirsutella thompsonii, associated with cassava mites in Benin, West Africa. Biocontr. Sci. Technol. 6: 23-33.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Elliot, S.L., Mumford, J.D., de Moraes, G.J. et al. Age-Dependent Rates of Infection of Cassava Green Mites by a Fungal Pathogen in Brazil. Exp Appl Acarol 27, 169–180 (2002). https://doi.org/10.1023/A:1021644321360
Issue Date:
DOI: https://doi.org/10.1023/A:1021644321360