University of California

Competitive displacement between ecological homologues


Paul DeBach
Ragnhild A. Sundby

Authors Affiliations

Paul DeBach was and , Department of Biological Control, Riverside; Ragnhild A. Sundby was , Zoological Institute, Agricultural College of Norway, Vollebekk, Norway.

Publication Information

Hilgardia 34(5):105-166. DOI:10.3733/hilg.v34n05p105. April 1963.

PDF of full article, Cite this article


Competitive displacement among three species of parasitic Hymenoptera which are ecological homologues has occurred in the field in southern California. Aphytis chrysomphali (Mercet) [Hymenoptera: Aphelinidae] was eliminated in 10 years (1948-1958) from nearly all of its former range—an area of some 4,000 square miles—by Aphytis lingnanensis Compere, which was imported from the Orient in 1948. Subsequently, Aphytis melinus DeBach, another exotic from India-Pakistan, virtually displaced A. lingnanensis from about 500 square miles of interior climatic areas in 4 years (1957-1961), but during the same time A. lingnanensis precluded the establishment of A. melinus in the milder intermediate climatic areas of San Diego County. Competitive displacement occurred in places in spite of food [the host scale insect, Aonidiella aurantii (Maskell)] being abundant. Thus food scarcity is not necessary for competitive displacement to occur. Two other species of parasites, Comperiella bifasciata Howard and Prospaltella perniciosi Tower, which attack the same host but are not ecological homologues of the Aphytis spp., continued to coexist with Aphytis spp.

Experimental studies in laboratory population cages supported and helped to explain the field results. Single species cultures served as checks and could be maintained indefinitely. Success in single species cultures, as determined by the average population density attained, was not correlated with inherent fecundity. When any two of the three species—Aphytis fisheri DeBach, A. melinus, and A. lingnanensis—were cultured together, one species always eventually eliminated the other. Differences in F1 progeny production explained the results. Inherent differences in fecundity were largely responsible for the differences in F1 progeny production, but aggressive competition between larvae tended to modify inherent fecundity. Competition between adults was not a factor in competitive displacement, but relative ability to find hosts in the field when hosts are scarce is important. Physical environmental conditions also affect F1 progeny production; hence, in different environments the winner in competition may differ.

When A. lingnanensis and A. fisheri were cultured together with a constant surplus of hosts, A. fisheri was eliminated after nine generations. This corroborates the field observations that food (host) scarcity is not necessary for competitive displacement to occur. Aphytis lingnanensis and Comperiella bifasciata, which have slightly different ecological niches, were shown to coexist in laboratory cultures as they do in the field. However, Prospaltella perniciosi was displaced. Reasons for this are discussed. Mechanisms of competitive displacement and the importance of competitive displacement in population ecology are also discussed.

Literature Cited

Andrewartha HG, Birch LC. The distribution and abundance of animals. 1954. Chicago, Illinois: The University of Chicago Press. 782p.

Andrewartha HG, Birch LC. Some recent contributions to the study of the distribution and abundance of insects. Ann. Eev. Entomol. 1960. 5:219-242. DOI: 10.1146/annurev.en.05.010160.001251 [CrossRef]

Benassy C, Bianchi H. Sur l’ecologie de Prospaltella perniciosi Tower (Hym. Aphelinidae), parasite specifique importe de Quadraspidiotus perniciosus Comst. (Horn. Diaspidinae). Entomophaga. 1960. 5(2):165-181. DOI: 10.1007/BF02374404 [CrossRef]

Brown WL Jr. Some zoological concepts applied to problems in evolution of the hominid lineage. Am. Scientist. 1958. 46(2):151-158.

Cole LC. Competitive exclusion. Science. 1960. 132(3423):348-349. DOI: 10.1126/science.132.3423.348 [CrossRef]

Compere H, Smith HS. Note on the life history of two Oriental chalcidoid parasites of Chrysomphalus. Univ. California Publ. Entomol. 1927. 4:63-73.

Connell JH. The influence of interspecific competition and other factors on the distribution of the barnacle Chthamalus stellatus. Ecology. 1961. 42(4):710-723. DOI: 10.2307/1933500 [CrossRef]

Crombie AC. On competition between different species of graminivorous insects. Roy. Soc. London, Proc, Ser. B. 1945. 132:362-395. DOI: 10.1098/rspb.1945.0003 [CrossRef]

Crombie AC. Further experiments on insect competition. Roy. Soc. London, Proc, Ser. B. 1946. 133:76-109. DOI: 10.1098/rspb.1946.0004 [CrossRef]

Crombie AC. Interspecific competition. J. Animal Ecol. 1947. 16:44-73. DOI: 10.2307/1506 [CrossRef]

Darwin Charles. On the origin of species. 1859. London: Cassell and Co., Ltd. 430p. Reprinted 1909 DOI: 10.1017/CBO9780511694295 [CrossRef]

DeBach Paul. The establishment in California of an Oriental strain of Prospaltella perniciosi Tower on the California red scale. J. Econ. Entomol. 1953. 46(6):1103

DeBach Paul. Relative efficacy of the red scale parasites Aphytis chrysomphali Mercet and Aphytis “A” on citrus trees in southern California. Portici Lab. Zool. Gen. e Agr. Boll. (Filippo Silvestri). 1954. 33:135-151.

DeBach Paul. New species and strains of Aphytis (Hymenoptera, Eulophidae) parasitic on the California red scale, Aonidiella aurantii (Mask.) in the Orient. Entomol. Soc. Am. Ann. 1959. 52(4):354-362.

DeBach Paul, Fisher TW, Landi John. Some effects of meteorological factors on all stages of Aphytis lingnanensis a parasite of the California red scale. Ecology. 1955. 36(4):743-753. DOI: 10.2307/1931311 [CrossRef]

DeBach Paul, Fleschner CA, Dietrick EJ. Natural control of the California red scale in untreated citrus orchards in southern California. Seventh Pacific Sci. Congr. Proc. 1953. 4:236-248.

DeBach Paul, Landi John. New parasites of California red scale. California Citrograph. 1959. 44(9):290-301-304.

DeBach Paul, Landi John. The introduced purple scale parasite, Aphytis lepidosaphes Compere, and a method of integrating chemical with biological control. Hilgardia. 1961. 31(14):459-497. DOI: 10.3733/hilg.v31n14p459 [CrossRef]

DeBach Paul, Sisojevi? Pelagija. Some effects of temperature and competition on the distribution and relative abundance of Aphytis lingnanensis and A. chrysomphali (Hymenoptera: Aphelinidae). Ecology. 1960. 41(1):153-160. DOI: 10.2307/1931948 [CrossRef]

DeBach Paul, White EB. Commercial mass culture of the California red scale parasite, Aphytis lingnanensis. California Agr. Expt. Sta. Bull. 1960. 770:58

Elton CS. Animal ecology. 1927. London: Sidgwick and Jackson. 207p.

Elton CS. The ecology of invasions by animals and plants. 1958. London: Methuen and Co. 181p. DOI: 10.1007/978-94-009-5851-7 [CrossRef]

Elton CS, Miller RS. The ecological survey of animal communities, with a practical system of classifying habitats by structural characters. J. Ecol. 1954. 42:460-496. DOI: 10.2307/2256872 [CrossRef]

Flanders SE. Observations on Comperiella bifasciata an endoparasite of diaspine coccids. Entomol. Soc. Am. Ann. 1944. 37(3):365-371.

Gause GF. The struggle for existence. 1934. Baltimore: Williams and Wilkins Co. 163p. DOI: 10.1097/00010694-193602000-00018 [CrossRef]

Hairston NG. Species abundance and community organization. Ecology. 1959. 40(3):404-416. DOI: 10.2307/1929757 [CrossRef]

Hardin Garrett. The competitive exclusion principle. Science. 1960. 131(3409):1292-1298. DOI: 10.1126/science.131.3409.1292 [CrossRef]

Kuenzler EJ. Niche relations of three species of lycosid spiders. Ecology. 1958. 39(3):494-500. DOI: 10.2307/1931759 [CrossRef]

Lack D. Ecological aspects of species formation in passerine birds. Ibis. 1944. 86:260-286. DOI: 10.1111/j.1474-919X.1944.tb04092.x [CrossRef]

Lawson FR. Some features of the relation of insects to their ecosystems. Ecology. 1958. 39(3):515-521. DOI: 10.2307/1931762 [CrossRef]

Lotka AJ. The growth of mixed populations: Two species competing for a common food supply. Washington Acad. Sci. J. 1932. 22:461 DOI: 10.1007/978-3-642-50151-7_12 [CrossRef]

McIntosh RP. Competitive exclusion principle. Science. 1961. 133(3450):391 DOI: 10.1126/science.133.3450.391 [CrossRef]

Milne A. Mechanisms in biological competition: definition of competition among animals. Symposia, Soc. Exptl. Biol. 1961. 15:40-61.

Nicholson AJ. The balance of animal populations. J. Animal Ecol. 1933. 2(1):132-178. DOI: 10.2307/954 [CrossRef]

Park T. Experimental studies of interspecies competition. I. Competition between populations of flour beetles, Tribolium confusum Duval and Tribolium castaneum. Herbst. Ecol. Monogr. 1948. 18:265-308. DOI: 10.2307/1948641 [CrossRef]

Park T. Experimental studies on interspecies competition. II. Temperature, humidity and competition in two species of Tribolium. Physiol. Zool. 1954. 28:177-238.

Park T. Ecological experimentation with animal populations. Sci. Month. 1955a. 81:271-275.

Park T. Experimental competition in beetles with some general implications. The numbers of man and animals. 1955b. London: Oliver and Boyd, Ltd. p. 69-82. for the Institute of Biology

Park T. Experimental studies on interspecies competition. III. Relation of initial species proportion to competitive outcome in populations of Tribolium. Physiol. Zool. 1957. 30:22-40.

Patten BC. Competitive exclusion. Science. 1961. 174(3490):1599-1601. DOI: 10.1126/science.134.3490.1599 [CrossRef]

Polnik Amelia. Effects of some intraspecies processes on competition between two species of flour beetles, Latheticus oryzae and Tribolium confusum. Physiol. Zool. 1960. 33(1):42-57.

Ross HH. Principle of natural coexistence indicated by leaf-hopper populations. Evolution. 1957. 11:113-129. DOI: 10.2307/2406045 [CrossRef]

Salt George. Mechanisms in biological competition: competition between insect parasitoids. Symposia Soc. Exptl. Biol. 1961. 15:96-119.

Savile DVO. Limitations of the competitive exclusion principle. Science. 1960. 132(3441):1761 DOI: 10.1126/science.132.3441.1761 [CrossRef]

Schlabritzky E. Prospaltella pemiciosi Tower—ein Beitrag zur biologischen Bekämpfung. Mitt. Biol. Bund. Berlin-Dahlem. 1956. 31:53-55.

Udvardy MFD. Notes on the ecological concepts of habitat, biotope and niche. Ecology. 1959. 40(4):725-728. DOI: 10.2307/1929830 [CrossRef]

Utida Syunro. Interspecific competition between two species of bean weevil. Ecology. 1953. 34(2):301-307. DOI: 10.2307/1930897 [CrossRef]

Van Valen Leigh. Further competitive exclusion. Science. 1960. 132(3440):1674-1675. DOI: 10.1126/science.132.3440.1674 [CrossRef]

Volterra vito. Variazioni e fluttuazioni del numero d’individui in specie animali conviventi. R. Accad. Naz. dei Lincie Mem., Ser. 6. 1926. 2:

Williamson MH. An elementary theory of interspecific competition. Nature. 1957. 180(4583):422-425. DOI: 10.1038/180422a0 [CrossRef]

DeBach P, Sundby R. 1963. Competitive displacement between ecological homologues. Hilgardia 34(5):105-166. DOI:10.3733/hilg.v34n05p105
Webmaster Email: sjosterman@ucanr.edu