Results of two field experiments showed that selective removal of omnivorous mosquito larvae (Aedes triseriatus (Say)) functioning as top predators in the food web of a temperate, tree hole ecosystem resulted rapidly in increased abundance of flagellate and then ciliate populations. Flagellate density increased from <1 per ml to >103 per ml within 4 days of omnivore removal, followed shortly thereafter by an increase in ciliate density from <1 per ml to >102 per ml, after which flagellate density declined, and flagellate and ciliate densities stabilized. Rod-shaped bacteria increased slightly in density after removal of larval mosquitoes, then declined as protist density increased. Cocciform bacteria did not vary in density with these changes, thus the trophic cascade dampened at the remotest trophic level. Concomitant with the increase in protist densities, some bacteria formed elongated filaments >10 µm in length, likely an anti-predation, morphological response stimulated by suddenly intensified grazing as protozoan density rose. Results suggest that feeding by omnivorous mosquito larvae exhibited strong top-down effects on flagellate and ciliate populations, depressing them to below their equilibrium densities and nearly to extinction in tree hole ecosystems.
Addicot, J.F. 1974. Predation and prey community structure: an experimental study of the effect of mosquito larvae on the protozoan communities of pitcher plants. Ecology 55: 475–492.
Brar, S., M. Verma, R.D. Tyagi and J.R. Valero. 2006. Recent advances in downstream processing and formulations of Bacillus thuringiensis based biopesticides. Process Biochem. 41: 323–342.
Carpenter, S.R. 1983. Resource limitation of mosquito larvae subsisting on beech detritus. Ecology 64: 219–223.
Carpenter, S.R. and J.F. Kitchell. 1993. The Trophic Cascade in Lakes. Cambridge University Press, New York, New York.
Cochran-Stafira, D. L. and C.N. von Ende. 1998. Integrating bacteria into food webs: Studies with Sarracenia purpurea inquilines. Ecology 79: 880–898.
Corno, G. and K. Jürgens. 2006. Direct and indirect effects of protist predation on the population size structure of a bacterial strain with high phenotypic plasticity. Appl. Environ. Microbiol. 72: 78–86.
Dadd, R. H. 1980. Essential fatty acids for the mosquito Culex pipiens. J. Nutrition 110: 1152–1160.
Eisenberg J.N.S., J.A. Washburn and S.J. Schreiber. 2000. Generalist feeding behaviors of Aedes sierrensis larvae and their effects on protozoan populations. Ecology 81: 921–935.
Fish, D. and S.R. Carpenter. 1982. Leaf litter and larval mosquito dynamics in tree-hole ecosystems. Ecology 63: 283–288.
Hahn, M. W., E.R.B. Moore and M.G. Höfle. 1999. Bacterial filament formation, a defense mechanism against flagellate grazing, is growth rate controlled in bacteria of different phyla. Appl. Environ. Microbiol. 65: 25–35.
Jürgens, K. 1994. Impact of Daphnia on planktonic microbial food webs – a review. Marine Microb. Food Webs 8: 295–324.
Jürgens, K., J. Pernthaler, S. Schalla, and R. Amann. 1999. Morphological and compositional changes in a planktonic bacterial community in response to enhanced protozoan grazing. Appl. Environ. Microbiol. 65: 1241–1250.
Kaufman M.G., S.N. Bland, M.E. Worthen, E.D. Walker and M.J. Klug. 2001. Bacterial and fungal biomass responses to feeding by larval Aedes triseriatus (Diptera: Culicidae). J. Med. Entomol. 38: 711–719.
Kaufman, M.G., S. Chen and E.D. Walker. 2008. Leaf-associated bacterial and fungal community shifts in response to larvae of the mosquito, Ochlerotatus triseriatus. Microbial Ecology 55: 673–684.
Kaufman, M.G., W. Goodfriend, A. Kohler-Garrigan, E.D. Walker and M.J. Klug. 2002. Soluble nutrient effects on microbial communities and mosquito production in Ochlerotatus triseriatus (Say) habitats. Aquatic Microb. Ecol. 29: 73–88.
Kaufman, M.G. and E.D. Walker. 2006. Indirect effects of soluble nitrogen on growth of Aedes triseriatus larvae in container habitats. J. Med. Entomol. 43: 677–688.
Kaufman M.G., E.D. Walker, T.W. Smith, R.W. Merritt and M.J. Klug. 1999. The effects of larval mosquitoes Aedes triseriatus and stemflow on microbial community dynamics in container habitats. Appl Environ Microbiol 65: 2661–2673.
King, C. H., R.W. Sanders, E.B. Shotts, Jr. and K.G. Porter. 1991. Differential survival of bacteria ingested by zooplankton from a stratified eutrophic lake. Limnol. Oceanogr. 36: 829–845.
Kitching, R. L. 1987. Spatial and temporal variation in food webs in water-filled treeholes. Oikos 48: 280–288.
Kitching, R. L. 2000. Food Webs and Container Habitats: The Natural History and Ecology of Phytotelmata. Cambridge University Press, Cambridge.
Kneitel, J.M. and T.E. Miller. 2002. Resource and top-predator regulation in the pitcher plant (Sarrecenia purpurea) inquiline community. Ecology 83: 680–688.
Laird, M. 1988. The Natural History of Larval Mosquito Habitats. Academic Press, London.
McCann, K. and I. Hastings. 1997. Re-evaluating the omnivory–stability relationship in food webs. Proc. R. Soc. London B 264: 1249–1254.
Merritt, R. W., R.H. Dadd and E.D. Walker. 1992. Feeding behavior, natural food, and nutritional relationships of larval mosquitoes. Annu. Rev. Entomol. 37: 349–76.
Paradise, C.J. and W.A. Dunson. 1998. Effects of sodium concentration on Aedes triseriatus (Diptera: Culicidae) and microorganisms in treeholes. J. Med. Entomol. 35: 839–844.
Pernthaler, J. 2005. Predation on prokaryotes in the water column and its ecological implications. Nature Rev. Microbiol. 3: 537–546.
Pernthaler, J., E. Zöllner, F. Warnecke and K. Jürgens. 2004. Bloom of filamentous bacteria in a mesotrophic lake: identity and potential controlling mechanism. Appl. Environ. Microbiol. 70: 6272–6281.
Pimm, S.L. 2002. Food Webs. University of Chicago Press, Chicago.
Pimm, S.L. and J.H. Lawton. 1978. On feeding on more than one trophic level. Nature 275: 542–544.
Polis, G.A., A.L.W. Sears, G.R. Huxel, D.R. Strong and J. Maron. 2000. When is a trophic cascade a trophic cascade? Trends in Ecology and Evolution 15: 473–5.
Polis, S.L. and D.R. Strong. 1996. Food web complexity and community dynamics. American Naturalist 147: 813–846.
SAS. 2001. Statistical analysis system, version 8.02. SAS Institute, Cary, North Carolina.
Simek, K., J. Vrba, J. Pernthaler, T. Posch, P. Hartman, J. Nedoma and R. Psenner. 1997. Morphological and compositional shifts in an experimental bacterial community influenced by protozoans with contrasting feeding modes. Appl. Environ. Microbiol. 63: 587–595.
Sommer, U., F. Sommer, B. Sonter, E. Zollne, K. Jürgens, C. Jamieson, M. Boersma and K. Gock. 2003. Daphnia versus copepod impact on summer phytoplankton: functional compensation at both trophic levels. Oecologia 135: 639–647.
Strong, D.R. 1992. Are trophic cascades all wet? The redundant differentiation in trophic architecture of high diversity ecosystems. Ecology 73: 747–754.
Thompson, R.M., B. Starzomski, M. Hemberg and J. Shurin. 2007. Trophic levels and trophic tangles: the prevalence of omnivory in real food webs. Ecology 88: 612–616.
Vadeboncoeur, Y., K.S. McCann, M. J. Vander Zanden and J.B. Rasmussen. 2005. Effects of multi-chain omnivory on the strength of trophic control in lakes. Ecosystems 8: 682–693.
Vandermeer, J. 2006. Omnivory and the stability of food webs. J. Theor. Biol. 238: 497–504.
von Ende, C.N. 2001. Repeated-measures analysis: growth and other time dependent measures. In: S. Scheiner and J. Gurevitch (eds). The Design and Analysis of Ecological Experiments. Oxford Univ. Press, Oxford. pp. 134–157.
Walker, E.D. 1995. Effect of low temperature on feeding rate of Aedes stimulans larvae and efficacy of Bacillus thuringiensis var. israelensis (H-14). J. Amer. Mosquito Control Assoc. 11: 107–110.
Walker, E.D., M.G. Kaufman, M.P. Ayres, M.H. Riedel and R.W. Merritt. 1997. Effect of variation in quality of leaf detritus on growth of the eastern tree hole mosquito, Aedes triseriatus (Diptera: Culicidae). Can. J. Zool. 75: 706–718.
Walker, E.D., D.L. Lawson, R. W. Merritt, W.T. Morgan and M.J. Klug. 1991. Nutrient dynamics, bacterial populations, and mosquito productivity in tree hole ecosystems. Ecology 72: 1529–1546.
Walker, E.D. and R.W. Merritt. 1988. The significance of leaf detritus to mosquito (Diptera: Culicidae) productivity from treeholes. Environ. Entomol. 17: 199–206.
Walker, E.D. and R.W. Merritt. 1991. Behavior of larval Aedes triseriatus (Diptera: Culicidae). J. Med. Entomol. 28: 581–589.
Walker, E.D., E.J. Olds and R.W. Merritt. 1988. Gut content analysis of mosquito larvae (Diptera: Culicidae) using DAPI stain and epifluorescence microscopy. J. Med. Entomol. 25: 551–554.
Washburn, J.A., M.E. Gross, D.R. Mercer and J.R. Anderson. 1988. Predator-induced trophic shift of a free-living ciliate: Parasitism of mosquito larvae by their prey. Science 240: 1193–1195.
Wu, Q. L., J. Boenigk and M.W. Hahn. 2004. Successful predation of filamentous bacteria by a nanoflagellate challenges current models of flagellate bacterivory. Appl. Environ. Microbiol. 70: 332–339.
Yodzis, P. 1984. How rare is omnivory? Ecology 65: 321–323.
Xu Y., S. Chen, M.G. Kaufman, S. Maknojia, M. Bagdasarian and E.D. Walker. 2008. Bacterial community structure in tree hole habitats of the larval mosquito, Ochlerotatus triseriatus: influences of larval feeding. J. Amer. Mosq. Control Assoc. 24: 219–227.
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Walker, E.D., Kaufman, M.G. & Merritt, R.W. An acute trophic cascade among microorganisms in the tree hole ecosystem following removal of omnivorous mosquito larvae. COMMUNITY ECOLOGY 11, 171–178 (2010). https://doi.org/10.1556/ComEc.11.2010.2.5
- Food web
- Tree holes
- Trophic cascade