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Impact of predation by the robber fly Proctacanthus milbertii (Diptera: Asilidae) on grasshopper (Orthoptera: Acrididae) populations


The impact of predation by the robber fly Proctacanthus milbertii Macquart on populations of adult grasshoppers from grasslands of the Nebraska sandhills was estimated. Densities of P. milbertii were estimated at 437 individuals per hectare (2 se=122). Overall densities of 23 species of grasshoppers were estimated to be 64,000 individuals per hectare with the most abundant species (Ageneotettix deorum) having a population size of approximately 15,000 individuals per hectare. Based on three estimates of predation level (ranging from 0.5 to 2 prey per day per robber fly), P. milbertii may take from 0.5% to 2% of the adult grasshoppers per day. Species of grasshoppers were taken by P. milbertii in about the same proportion in which they occurred at the study site and no size-selective component of predation was detectable.

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  1. Baker NT, Rischer RL (1975) A taxonomic and ecologic study of the Asilidae of Michigan. Great Lakes Entomol 8:31–91

  2. Bromley SW (1914) Asilids and their prey. Psyche 21:192–198

  3. Bromley SW (1923) Observations on the feeding habits of robberflies. Part I. Psyche 30:41–45

  4. Bromley SW (1949) The Missouri bee-killer, Proctacanthus milbertii Macq. (Asilidae: Diptera). Bull Brooklyn Entomol Soc 44:21–28

  5. Chapman, RF, Paige WW, Cook AG (1979) A study of population changes in the grasshopper Zonocerus variegatus in Southern Nigeria. J Anim Ecol 48:247–270

  6. Dempster JP (1963) The populations dynamics of grasshoppers and locusts. Biol Rev 38:490–529

  7. Dennis DW, Lavigne RJ (1975) Comparative Behavior of Wyoming robber flies (Diptera Asilidae) II. Univ Wyoming Agric Exp Sta Sci Monograph No 30. 68 p

  8. Greathead DG (1963) A review of the insect enemies of Acrididae (Orthoptera). Trans R Ent Soc, London 114:437–517

  9. Greathead DG (1966) A brief survey of the effects of biotic factors on populations of the desert locust. J Appl Ecol 3:239–250

  10. Hespenheide H (1973) Ecological inferences from morphological data. Ann Rev Ecol Syst 4:213–229

  11. Huddleston JA (1958) Some notes on the effects of bird predators on hopper bands of the desert locust (Schistocerca gregaria). Ent Mon Mag 94:210–214

  12. Jolly GM (1965) Explicit estimates from capture-recapture data with both death and immigration — stochastic model. Biometrika 52:225–247

  13. Keeler K, Harrison AT, Vescio LS (1980) The Flora and sandhills communities of Arapaho Prairie, Arthur County, Nebraska. Prairie Naturalist 12:65–78

  14. Lavigne RJ, Holland FR (1969) Comparative behavior of Wyoming robber flies (Diptera: Asilidae). Univ Wyoming Agric Exp Sta Sci Monogr No 18. 61 p

  15. Lavigne RJ, Pfadt RE (1966) Parasites and predators of Wyoming rangeland grasshoppers. Univ Wyoming Agr Exp Sta Sci Monogr No 3. 31 p

  16. Lehr PA (1964) On the nutrition and significance of robber flies. Trud nauchno-issled Inst Zasch Rast, KazASKhN, Alma Ata 8:213–244 (in Russian)

  17. Linsley EG (1960) Ethology of some bee- and wasp-killing robber flies of southeastern Arizona and western New Mexico. Univ California Publ Entomol 16:357–381

  18. Onsager JA (1977) Comparison of methods for estimating density of rangeland grasshoppers. J Econ Entomol 70:187–190

  19. Pfadt RA (1977) Some aspects of the ecology of grasshopper populations inhabiting the shortgrass plains. Univ Minnesota Agric Exp Sta Tech Bull 310:73–79

  20. Rees NE (1973) Arthropod and nematode parasites, parasitoids, and predators of Acrididae in America north of Mexico. USDA Tech Bull No 1460. 288 p

  21. Rogers LE, Lavigne RJ (1972) Asilidae of the Pawnee National Grasslands, in northern Colorado. Univ Wyoming Agric Exp Sta Sci Monogr No 25. 35 p

  22. Seber GAF (1973) The estimation of animal abundance and related parameters. Griffin, London 506 p

  23. Shurovnekov BG (1962) Field entomophagous predators (Coleoptera, Carabidae and Diptera, Asilidae) and factors determining their efficiency. Ent Rev 41:476–485

  24. Smith KD, Popov GB (1953) On birds attacking locusts in Eritrea. Entomol 86:3–7

  25. Southwood TRE (1966) Ecological methods. Chapman and Hall. London 542 p

  26. Stower WJ, Greathead DJ (1969) Numerical changes in a population of the desert locust, with special reference to factors responsible for mortality. J Appl Ecol 6:203–235

  27. Tanner JT (1978) Guide to the study of animal populations. University of Tennessee Press, Knoxville

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Correspondence to Anthony Joern.

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Joern, A., Rudd, N.T. Impact of predation by the robber fly Proctacanthus milbertii (Diptera: Asilidae) on grasshopper (Orthoptera: Acrididae) populations. Oecologia 55, 42–46 (1982). https://doi.org/10.1007/BF00386716

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  • Population Size
  • Abundant Species
  • Predation Level
  • Adult Grasshopper