Competitive displacement: extinction of the yellow scale, Aonidiella citrina (Coq.) (Homoptera: Diaspididae), by its ecological homologue, the California red scale, Aonidiella aurantii (Mask.) in Southern California
Robert M. Hendrickson
Authors AffiliationsPaul DeBach was Professor of Biological Control and Entomologist in the Experiment Station, University of California, Riverside; Robert M. Hendrickson, Jr. was Research Entomologist, United States Department of Agriculture, Beneficial Insect Research Laboratory, Newark, Delaware; Mike Rose was Staff Research Associate in the Experiment Station, University of California, Riverside.
Hilgardia 46(1):1-35. DOI:10.3733/hilg.v46n01p001. March 1978.
Discussion, historical data, and laboratory experiments are used to show that competitive displacement may occur even when there are no apparent shortages of requisites or direct aggression between ecological homologues. The final determinant is a relative difference in effective progeny production, R (as modified or even reversed by other environmental factors—such as natural enemies). These concepts are opposed to those of (Huffaker and Laing (1972)) who consider “escape from natural enemies” or the effects of other extrinsic factors as resources or requisites.
The decline of yellow scale, Aonidiella citrina, on citrus in southern California was documented with changes in distribution and abundance mapped from earliest records until its extinction sometime in the 1960s. Possible explanations—such as natural enemies, insecticides, and climate, were examined and found untenable. Extinction took place only where California red scale, A. aurantii, was present with yellow scale for a number of years. This led to the hypothesis that the California red scale was an ecological homologue of the yellow scale and that competitive displacement was responsible for extinction.
Results of laboratory tests all favored California red scale: (1) Gross fecundity, sex ratio, minimum and average time per generation were better, and more crawlers of California red scale than yellow scale survived to reproduce. (2) Computer calculation of the compound effective progeny production of a female scale and that part of her progeny which were themselves producing crawlers showed the “compound-interest” effect (California red
Andrewartha H. G., Birch L. C. The distribution and abundance of animals. 1954. Chicago: University of Chicago Press. 782p.
Bliss C. I., Broadbent B. M., Watson S. A. The life history of the California red scale Chrysomphalus aurantii Maskell: progress report. Jour. Econ. Ent. 1931. 24(6):1222-9.
Cole L. C. Competitive exclusion. Science. 1960. 132(3423):348-9. DOI: 10.1126/science.132.3423.348 [CrossRef]
Compere H. The red scale and its insect enemies. Hilgardia. 1961. 31(7):173-278. DOI: 10.3733/hilg.v31n07p173 [CrossRef]
Coquillett D. W. Report on various methods for destroying scale insects. U.S. Dept. Agr., Div. Ent. Bull. 1891. 23:19-36.
Darwin C. On the origin of species. Repr. 1909. 1859. London: Cassel &; Co., Ltd. 430p.
DeBach P. The competitive displacement and coexistence principles. Ann. Rev. Ent. 1966. 11:183-212. DOI: 10.1146/annurev.en.11.010166.001151 [CrossRef]
DeBach P. Biological control of diaspine scale insects on citrus in California. Proc. 1st Intern. Citrus Symp. 1969. 2:801-15.
DeBach P. Effects of interspecific competition among species of diaspine scales and their parasites. 12th Pac. Sci. Congr. 1971. 1:198-9.
DeBach P., Fisher T. W. Experimental evidence for sibling species in the oleander scale, Aspidiotus hederae (Vallot). Ann. Ent. Soc. Amer. 1956. 49(3):235-9.
DeBach P., Sundby R. A. Competitive displacement between ecological homologues. Hilgardia. 1963. 34(5):105-66. DOI: 10.3733/hilg.v34n05p105 [CrossRef]
Ebeling W. Subtropical entomology. Lithotype Process 1950. p.vii + 747. San Francisco
Ebeling W. Subtropical fruit pests. 1959. University of California Press. vii + 436p.
Flanders S. E. Biological control of yellow scale. Calif. Citrog. 1948. 34:56 76-7
Flanders S. E. Struggle for existence between red and yellow scales on citrus. Citrus Leaves. 1956. 36(8):6 7, 22, 26, 31
Flanders S. E., Gressitt J. L. The natural control of California red scale in China. Calif. Dept. Agr. Bull. 1958. 47(1):23-33.
Hardin G. Nature and man’s fate. 1959. New York: Rinehart.
Hardin G. The competitive exclusion principle. Science. 1960. 131(3409):1292-7. DOI: 10.1126/science.131.3409.1292 [CrossRef]
Huffaker C. B., Laing J. E. “Competitive displacement” without a shortage of resources? Res. Popul. Ecol. 1972. 14(1):1-17. DOI: 10.1007/BF02511182 [CrossRef]
Mackie D. G. Report of Division of Plant Industry, Bureau of Entomology and Plant Quarantine. Calif. Dept. Agr. Bull. 1941. 30(4):337-57.
McKenzie H. L. Morphological differences distinguishing California red scale, yellow scale, and related species. Univ. Calif. Pub. Ent. 1937. 6:323-36.
Moreno D. S., Rice R. E., Carman G. E. Specificity of the sex pheromones of female yellow scales and California red scales. Jour. Econ. Ent. 1972. 65(3):698-701.
Munger F. Reproduction and mortality of California red scales resistant and nonresistant to hydrocyanic acid gas, as affected by temperature. Jour. Agr. Res. 1948. 76(7-8):153-63.
Munger F., Cressman A. W. Effect of constant and fluctuating temperatures on the rate of development of California red scale. Jour. Econ. Ent. 1948. 41(3):424-7.
Nel R. G. A comparison of Aonidiella aurantii and Aonidiella citrina, including a study of the internal anatomy of the latter. Hilgardia. 1933. 7(11):417-66. DOI: 10.3733/hilg.v07n11p417 [CrossRef]
Nicholson A. J. The balance of animal populations. Jour. Anim. Ecol. 1933. 2(1):132-78. DOI: 10.2307/954 [CrossRef]
Quayle H. J. Citrus fruit insects. Univ. Calif. Agr. Exp. Sta. Bull. 1911a. 214:439-512.
Quayle H. J. The red or orange scale. Univ. Calif. Agr. Exp. Sta. Bull. 1911b. 222:96-150.
Quayle H. J. Insects of citrus and other subtropical fruits. 1938. Ithaca, New York: Comstock Pub. Co. 583p.
Quezada J. R., DeBach P. Bioecological and population studies of the cottony-cushion scale, Icerya purchasi Mask., and its natural enemies, Rodolia cardinalis Muls. and Cryptochaetum iceryae Will., in southern California. Hilgardia. 1973. 41(20):631-88. DOI: 10.3733/hilg.v41n20p631 [CrossRef]
Schweig C., Grunberg A. The problem of black scale (Chrysomphalus ficus, Ashm.) in Palestine. Bul. Ent. Res. 1936. 27:677-713.
Tashiro H., Beavers J. B. Growth and development of the California red scale, Aonidiella aurantii. Ann. Ent. Soc. Amer. 1968. 61(4):1009-14.
Woglum R. S. What about yellow scale? Calif. Citrog. 1932. 17(3):93 117
Yust H. R. Productivity of the California red scale on lemon fruits. Jour. Econ. Ent. 1943. 36(6):868-72.
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