FILE: <bc-12.htm> GENERAL INDEX [Navigate to MAIN MENU ]
[For
educational purposes only; do not review, quote or abstract]
COMPETITIVE DISPLACEMENT, EXCLUSION
AND COEXISTENCE Among Arthropods
(Contacts)
---- Please
CLICK on
desired underlined categories [to search for Subject
Matter, depress Ctrl/F ]:
|
[Please refer also to Selected Reviews |
|
Overview All organisms have certain
habitable zones delimited by physical parameters outside of which they cannot
persist by themselves. This can be a result of parasitism and predation, or
of gross physical stresses. Within the habitable zone long established
species usually exhibit a typical average density with generally
narrow fluctuations. Species may be designated as rare, common
or abundant. Ecologists have paid most
attention to fluctuations of abundance, while too little thought has been
given to reasons for the rarity or absence of a species
altogether. Such scarcity is especially intriguing when physical conditions
seem optimum. Some species reach these areas from time to time, but they do
not persist. Extinction will often occur in a particular area when residence
had been temporarily established. The absence of a species from a
habitat may be due to unsuitable physical factors or the lack of physical or
biological requisites, geographic isolation (islands, mountains), or
interspecific actions Interspecific actions in the form
of multiple parasitism was probably best illustrated by H. S. Smith (1929).
DeBach (1966) discussed the competitive
displacement "principle." Various synonyms for this
idea are Gause's Law (1934), Grinnell's
Axiom (1943), the Volterra-Gause Principle (Hutchinson
1957, 1960), and the Competitive Exclusion
Principle (Hardin 1960). DeBach's definition of the
competitive displacement principle , "different species having identical
ecological niches (= ecological homologues) cannot coexist for long in the
same habitat," admits that all species differ biologically no matter how
closely related they are, or however similar they may be in habits.
Competitive exclusion is also included in the definition because the complete
exclusion of an invader rarely occurs. More than likely, some individuals
gain a foothold and competitive displacement follows. Verification of competitive
displacement in the field was rare prior to the 1960's. Connell (1961)
learned that the intertidal distribution of barnacles was limited by
interspecific competition. DeBach & Sundby (1963) reported that Aphytis
lingnanensis, within 10 years following its importation in 1948, had
displaced its ecological homologue, Aphytis chrysomphali
(mercet) from nearly the entire geographic distribution of the latter (ca.
4,000 sq-miles). Sarotherodon (Tilapia) hornorum has
displaced S. mossambica and Tilapia zillii from
drainage channels in the south coastal area of California, probably because S.
hornorum is the most euryhaline (tolerant of salt water). Daily ocean
tides bathe the primary breeding habitat (Legner 1986a, Legner &
Sjogren 1984). Another
possible case of displacement involves the apparent replacement of Hippelates
robertsoni by H. impressus, a recent invader from
Mexico, in the Riverside, California area. Mechanisms of Competitive
Displacement The basis of competitive
displacement is simple. The winner is the species which produces the most
female progeny which survive to reproduce per unit of time. Other mechanisms
may complicate the process of competitive displacement by affecting the
progeny production of one species relative to the other. These include
host-finding, host recognition, active interference between species,
cannibalism, disease, predation, genetic drift and changes in the physical
conditions Ernst Mayr (1948) writing on natural selection stated that
"Individuals of two species with identical ecological requirements would
be subject to the same competition for space and food as if they were members
of a single species. However, since the two species are genetically
different, one of them will undoubtedly be slightly superior to the other in
a given habitat. Natural selection will discriminate against the less efficient
individuals [presumably less fecund with respect to R] and thus
eventually eliminate the less efficient species." Nicholson (1957) on the subject of
natural selection, wrote "Within a species population all individuals
have essentially the same properties and requirements and no competition
amongst them is complete. Consequently, if by mutation or some other change
in their genes, individuals appear which have an advantage over other
individuals that causes them to leave more surviving offspring than
individuals of the original form, this new form will inevitably displace the
original form from all places in which they have the advantage, no matter how
small this advantage may be." It is generally believed that
requisites must be in short supply for competition and displacement to
occur. DeBach opposed this viewpoint and refers to Dobzhansky's (1961)
statement that natural selection may take place when resources are not
limiting. Fitness is merely a measure of
reproductive proficiency. DeBAch stated that inasmuch as most insect
populations in nature are under natural control by factors which hold their
densities below a ceiling where food shortage becomes critical and begins to
limit their populations, short supply of food or space is usually not a
factor. Additionally, DeBach and Sundby (1963) showed that competitive
displacement between species of Aphytis occurred both in the field and
laboratory when food (hosts) was abundant in relation to immediate needs. In competitive displacement, the
winner may not always be the same species. There can be different outcomes in
different habitats (eg., Gause 1934, Hutchinson & Deevey 1949). Also
involved are differences in temperature, humidity, disease, pH, food quality
and perhaps irradiation. The initial numbers usually are
not important in influencing which species wins, except under special
conditions (Crombie 1945, Park 1957). If competitive abilities of the two
contestants are evenly balanced, chance determines the outcome. However,
greater probability may lie with the one having the greatest initial
population density. Genetic heterogeneity may
influence the outcome: the more the genetic variation is reduced by
inbreeding, the more determinate the outcome of competition becomes. Most past cases of competitive
displacement are history and difficult to verify. There remain numerous cases
where closely related species are allopatric except for a narrow band of
overlap where they come together. These overlapping bands are believed to
represent cases of competitive displacement. However, they also could involve
adaptation to different physical conditions (see Remington 1986). Some more examples of field competitive displacement are as follows: 1. Wheat stem sawflies in the
northeastern United States. Cephus pygmaeus (L.) occurs east of
the Delaware-Erie line, while C. tabidus Fab. occurs west of
this line. They overlap narrowly in the center. Elton calls this "Mutually
exclusive distribution." 2. DeBach & Sundby (1963) and Luck (1985) present the very
decisive case of Aphytis parasitoids on red scale in southern
California. 3. Connell (1961) gives
experimentally decisive evidence with barnacles off the coast of Scotland. 4. DeBach (1966) showed how Aphytis
melinus DeBach rapidly displaced A. lingnanensis in the
interior citrus areas of southern California, but more slowly in coastal
areas. Aphytis lingnanensis became virtually extinct in the
interior areas by 1964. 5. The exotic Mediterranean fruit fly, Ceratitis capitata
(Wiedemann), was replaced around Sydney, Australia by the Queensland fruit
fly, Dacus tryoni (Froggatt) which invaded from the north
(Andrewartha & Birch 1954). 6. In Hawaii, the Mediterranean
fruit fly was displaced by the Oriental fruit fly, Dacus dorsalis
Hendel, in littoral areas. The Mediterranean fruit fly is now restricted
entirely to cool climates at higher elevations. 7. The introduced parasitoids of Dacus
dorsalis also showed displacements in Hawaii. Opius longicaudatus
(Ashmead) and Opius vandenboschi Fulla A corollary of the Competitive
Displacement Principle is the Coexistence Principle. Coexistence maintains
that different species which coexist indefinitely in the same habitat must
have different ecological niches; i.e., they cannot be ecological homologues. Coexistence between ecological
homologues is theoretical. it might occur if both species exist at such low
densities that competition does not occur (Crombie 1947, Dumas 1956). It
probably never will actually occur, however. What probably happens is that
displacement at low densities is greatly lengthened. It might also be possible for two
species to coexist homologously if each has different regulatory factors
(Harper et al. 1961, Klomp 1961, MacArthur 1958, Nicholson 1957). There is no
argument about the coexistence of such species since by having different
regulatory factors, they are not true ecological homologues. The continued reversal of habitat
variation has been suggested as a mechanism whereby two homologues can
coexist (Hutchinson 1949). Klomp (1961) thought this can occur only if
habitat variation is dependent on the numerical ratio of the species
involved. This is very improbable. way
were extremely scarce after Opius oophilus fullaway was
introduced. 8. The California red scale, Aonidiella
aurantii, has completely replaced the yellow scale, Aonidiella citrina
(Coquillett) in the presence of abundant food in southern California (DeBach
& Sundby 1963). Aonidiella citrina is thought to have been
handicapped by more effective natural enemies in its competition with A.
aurantii. 9. The imported black scale
parasitoid, Scutellista cyanea Motschulsky, largely replaced
its indigenous ecological homologue Moranila californica
(Howard) (Flanders 1958). 10. The European cabbage
butterfly, Pieris rapae (L.) displaced the native Pieris
oleracea Harris entirely from a large area. The checkered white
butterfly, Pieris protodice Boisduval & LeConte, also
greatly decreased in density. 11. In Israel the mealybug
parasitoid, Clausenia purpurea Ishii, displaced the established
parasitoids Leptomastix flavus Mercet and Anagyrus kivuensis
Compere (Rivnay 1964). 12. Displacement of Rhodesgrass
scale parasitoid, Anagyrus antoninae by Neodusmetia sangwani
in Texas (Schuster & Dean 1976). The Coexistence
Principle Utida (1957) believed that the superior
ability of one homologue to utilize a common requisite is offset by the
superior ability of the other to discover and exploit unutilized sources of
the common requisite. Klomp (1961) challenged this because obviously the
second species occurs in parts of the habitat in which the first is absent;
hence, they are not true homologues. It has been proposed that two
ecologically homologous species of parasitic wasps, if not host regulative
can coexist on a common host whose population fluctuates, if one has an
advantage at high host densities and the other at low host densities. Utida
(1957) thought this probably applies to the parasitoids attacking different
host stages, in which case they are not homologues and could coexist. Other examples where it was
thought that homologues coexisted are reported by Heatwole and Davis (1965),
who observed that three species of Megarhyssa coexisted on the same
host. In this instance they were not homologous because each possessed
ovipositors of different lengths. Ross (1957) discussed six closely related
species of the lawsoni complex of the leafhopper genus Erythroneura.
All six breed on sycamore, appear to have identical habits, mature
synchronously in each locality, hibernate together and feed in the same
manner, often side-by-side on the same leaf. Coexistence was possible
probably because certain species have advantages in different habitats. Diver
(1940) declared three species of closely related syrphid flies homologous.
However, he did not study the habits and host specificity of the larvae.
Schwerdtfeger (1942) documented the coexistence of four genera of
caterpillars in Germany from 1880 to 1940: Panolis, Hyloicus, Dendrolimus,
and Bupalis on Pinus sylvestris L. Again, this
coexistence can be explained on the basis that each caterpillar was different
"ecologically." Utida (1957) has some exceptions which might
require closer examination. Otherwise, generally speaking, laboratory
experiments usually show one species with different requirements, habits,
etc., when examined carefully. Competitive Displacement
of Non-homologues Non-homologues have similar but
not identical ecological niches. Competitive displacement of one by the other
requires that the broad niche of one must completely overlap the narrow niche
of the other. Examples are as follows: 1. If Dutch elm disease should
kill all American elm trees, it would eliminate all insects specific to the
American elm. 2. Highly effective insects, such
as the Klamath weed beetles, which reduce the Klamath weed to very low
population densities, may be responsible for the elimination of other insects
specific to the weed because the area of discovery of the other insects is
too low to permit existence. 3. A highly effective parasitoid
of one stage of an insect is compared to an ineffective one on a later stage:
the first would reduce host populations and eliminate the second in the same
habitat. 4. Generally, an herbivorous
mammal might exterminate a moth through excessive reductions of their common
food supply (Nicholson 1957). Contemporary ecologists believe that this would
only happen locally but not generally, because a moth can survive on much
less food than the herbivore. 5. Terrestrial organisms that
alter large habitats, such as scarab beetles, are especially risky biological
control candidates because their activity may overlap portions of the niche
of other species, so that potential disruptive side effects among organisms
in different guilds exist. The outcome for future symbovine fly control may
be undesirable in that some potentially regulative natural enemies, such as
certain predatory arthropods, may now be difficult to establish in the
disrupted habitat. In the southwestern United States, the predatory
staphylinid genus Philonthus is severely restrained from colonizing
the drier dung habitat created by Onthophagus gazella F.
activity. Thus, the scarab, a non-homologue, may largely displace members of
the genus Philonthus (Legner 1986b ). One might reasonably surmise that
all competitive displacement actually occurs between non-homologues,
especially when in the final analysis it is extremely difficult to find true
homologues. Even two individuals of the same species are never exactly the
same in the genetic sense. An informative review of competitive displacement
and exclusion is given by Ayala (1969), where it is demonstrated that two
species of Drosophila competing for limited resources of food and
space can coexist. Although the principle of competitive exclusion was
rejected, along with Gause's principle (Ayala 1969), there were sufficient
differences in the competing species to account for their coexistence. Competitive Displacement
and Biological Control Biological control offers a good
arena for the study of competitive displacement because natural enemies which
share the same food and which may approximate the ecological homologue status
are purposely and commonly brought together into the same habitat. Biological
control work since Smith (1929) has shown that competition between
parasitoids in multiple introductions has never caused a less effective host
regulation level. A second importation can only add to the effectiveness of
the first if chosen carefully (Legner 1986a ). Competitive displacement may prove
of practical value in insect eradication. The use of an ecological homologue
which itself is not a pest, may be used for displacement of a pest. For
example, Hermetia illucens (L.), the soldier fly, can eliminate
Musca domestica breeding by larval competition. The action
comes about by Hermetia changing the substrate to a semi-liquid, which
is not suitable for Musca. Hermetia is effective in this
capacity only in certain relatively humid areas and not broadly throughout
any given area, so that competition results in a reduction and not
elimination of Musca. It is been suggested that mosquitoes
and other pests of medical importance might be replaced through larval
competition of a pest of humans by an ecological homologue which only attacks
animals. In Sardinia, Anopheles labranchiae Falleroni, a vector
of malaria, was largely replaced by A. hispaniola (Theobald), a
non-vector. Relative survival of the non-vector was favored under the
eradication measures used. Eradication did not continue long enough, however,
to allow for complete displacement to occur. In East Africa, spraying houses
with dieldrin to control Anopheles funestus Giles, a serious
malaria vector, led to the mosquito's replacement by A. rivulorum
Leeson. Anopheles rivulorum is zoophilous, preferring cattle,
so its increase did not obstruct the goal of malaria control. Fruit flies might also be
promising targets for competitive displacement, as exemplified by the
accidental cases of displacement in Australia and Hawaii that were previously
discussed. Hippelates eye gnats might also be controlled with this
method, although the alternative should be carefully screened for possible
undesirable attributes (Legner 1970). Exercise 12.1--How may competitive displacement be used to our
advantage in pest management? Exercise 12.2--What is an ecological homologue? Exercise 12.3--Describe in some detail at least 6 examples of
competitive displacement in nature. Exercise 12.4--Distinguish competitive displacement, exclusion and
coexistence. Exercise 12.5--Distinguish between competitive displacement by
homologues and non-homologues. REFERENCES: [ Additional
references may be found at MELVYL Library ] Aitken,
T. H. G. & H. Trapido. 1961. Replacement phenomenon observed amongst
Sardinian anopheline mosquitoes following eradication measures. In:
"The Ecological Effects of Biological and Chemical Control of
Undesirable Plants and Animals." p. 106-14. Symp. 8th Tech. Meeting Intern.
Union for Conserv. Nature & Nat. Resources, Warsaw. E. J. Brill Publ.,
Leiden, Netherlands. Andrewartha,
H. G. 1963. Introduction to the Study of Animal Populations. Univ. of Chicago
Press, Chicago. 281 p. Andrewartha,
H. G. & L. C. Birch. 1960. Some recent contributions to the study of the
distribution and abundance of insects. Ann. Rev. Ent. 5: 219-42. Andrewartha,
H. G. & T. O. Browning. 1958. Williamson's theory of interspecific
competition. Nature 181(4620): 1415. Andrewartha,
H. G. & L. O. Birch. 1954. The Distribution and Abundance of Animals.
Univ. of Chicago Press, Chicago. 782 p. Arbuthnot,
K. D. 1955. European corn borer parasite complex near East Hartford,
Connecticut. J. Econ. Ent. 48: 91-93. Ayala,
F. J. 1969. Experimental invalidation of the principle of competitive
exclusion. Nature 224: 1076-79. Ayala,
F. J. 1972. Competition between species. Amer. Scient. 60: 348-57. Bartlett,
M. S. 1957. On theoretical models for competitive and predatory biological
systems. Biometrika 44: 27-42. Bartlett,
B. R. & J. C. Ball. 1964. The developmental biologies of two encyrtid
parasites of Coccus hesperidum and their intrinsic competition.
Ann. ent. Soc. Amer. 57: 496-503. Beauchamp,
R. S. A. & P. Ullyett. 1932. Competitive relationships between certain
species of freshwater triclads. J. Econ. 20: 200-208. Beddington,
J. R. et al. 1978. Characteristics of successful natural enemies in models of
biological control of insect pests. Nature 273: 513-19. [A discussion of
attributes of effective natural enemies based on theoretical models]. Beirne,
B. P. 1960. Biological control research in Canada. In:
"Biological Control of Insects of Medical Importance." Amer. Inst.
Biol. Sci. Publ. Tech. Rept. 94-97. Bellows,
T. S., Jr. & T. W. Fisher, (eds) 1999. Handbook of Biological Control:
Principles and Applications. Academic Press, San Diego, CA. 1046 p. Bess,
H. A., R. van den Bosch & F. R. Haramoto. 1961. Fruit fly parasites and
their activities in Hawaii. Proc. Hawaiian Ent. Soc. 17: 367-78. Birch,
L. c. 1957. The meanings of competition. Amer. Naturalist 91: 5-18. Birch,
L. C. 1953. Experimental background to the study of the distribution and
abundance of insects. III. The relation between innate capacity for increase
and survival of different species of beetles living together on the same
food. Evolution 7: 136-44. Birch,
L. C. 1961. Natural selection between two species of tephritid fruit flies of
the genus Dacus. Evolution 15: 360-74. Bowers,
D. E. 1964. Natural history of two beach hoppers of the genus Orchestoidea
with reference to their complemental distribution. Ecology 45: 677-96. Brian,
M. V. 1956. Segregation of species of the ant genus Myrmica. J. Anim.
Ecol. 25: 319-37. Brower,
L. P. 1962. Evidence for interspecific competition in natural populations of
the monarch and queen butterflies, Danus plexippus and D.
qilippus berenice in south central Florida. Ecology 43: 549-52. Brown,
W. L., Jr. & E. O. Wilson. 1956. Character displacement. Syst. Zool. 5:
49-64. Caldwell,
L. D. & J. B. Gentry. 1965. Interactions of Peromyscus and Mus
in a one-acre field enclosure. Ecology 46: 189-92. Campbell,
A. et al. 1974. Temperature requirements of some aphids and their parasites.
J. Applied Ecology 11: 431-38. [Last paragraph addresses why some parasitoids
may be incapable of controlling their hosts]. Chaing,
C. L. 1954. Competition and other interactions between species. In:
"Statistics and Mathematics in Biology," p. 197-215. Iowa St. Coll.
Press, Ames. Christenson,
L. D. & R. H. Foote. 1960. Biology of fruit flies. Ann. Rev. Ent. 5:
171-92. Clark,
A. H. 1931. The extirpation of one butterfly by another. Sci. Monthly 33(2):
173-74. Cole,
L. C. 1960. Competitive exclusion. Science 132(3423): 348-49. Connell,
J. H. 1961. The influence of interspecific competition and other factors on
the distribution of the barnacle Chthamalus stellatus. Ecology
42: 710-23. Cooper,
D. M. & T. Dobzhansky. 1956. Studies on the ecology of Drosophila
in the Yosemite region of California. I. The occurrence of species of Drosophila
in different life zones and at different seasons. Ecology 37: 526-33. Crombie,
A. C. 1945. On competition between different species of graminivorous
insects. Proc. Roy. Soc. (London) B, 132: 362-95. Crombie,
A. C. 1946. Further experiments on insect competition. Proc. Roy. Soc.
(London) B, 133: 76-109. Crombie,
A. C. 1947. Interspecific competition. J. Anim. Ecol. 16: 44-73. Cunha,
A. B. da, T. Dobzhansky & A. Sokoloff. 1951. On food preferences of
sympatric species of Drosophila. Evolution 5: 97-101. Dawson,
P. S. & I. M. Lerner. 1962. Genetic variation and indeterminism in
interspecific competition. Amer. Naturalist 96(891): 379-80. Darwin,
C. 1909. On the Origin of Species (1859). Reprinted by Cassell & Co.,
Ltd., London. 430 p. DeBach,
P. 1954. Relative efficacy of the red scale parasites Aphytis chrysomphali
Mercet and Aphytis "A" on citrus trees in southern
California. Boll. Lab. Zool. Agr., Portici, 33: 135-51. DeBach,
P. & P. Sisojevic. 1960. Some effects of temperature and competition on
the distribution and relative abundance of Aphytis lingnanensis
and A. chrysomphali. Ecology 41: 153-60. DeBach,
P. 1962. Ecological adaptation of parasites and competition between parasite
species in relation to establishment and success. Proc. 11th Intern. Congr.
Ent., Wien, 1960, 11: 686-90. DeBach,
P. 1964. Some ecological aspects of insect eradication. Bull. Ent. Soc. Amer.
10(4): 221-24. DeBach,
P. 1965. Some biological and ecological phenomena associated with colonizing
entomophagous insects. In: "Genetics of Colonizing Species."
Academic Press, N.Y. DeBach,
P. 1966. The competitive displacement and coexistence principles. Ann. Rev.
Ent. 11: 183-212. DeBach,
P. & R. A. Sundby. 1963. Competitive displacement between ecological
homologues. Hilgardia 34: 105-66. Diver,
C. 1940. The problem of closely related species living in the same area. In:
"The New Systematics." p. 303-28. Huxley, J. (ed.), Oxford Univ.
Press, London. Dobzhansky,
T. 1961. Man and natural selection. Amer. Scientist 49(3): 285-99. Doutt,
R. L. & P. DeBach. 1964. Some biological control concepts and questions. In:
"Biological Control of Insect Pests and Weeds." Chap. 5, 124-28. P.
DeBach (ed.). Chapman & Hall, London, Reinhold, N.Y. 844 p. Dumas,
P. C. 1956. The ecological relations of sympatry in Plethodon dunni
and Plethodon vehiculum. Ecology 37: 484-95. Dumas,
P. C. 1964. Species-pair allopatry in the genera Rana and Phrynosoma.
Ecology 45: 178-81. Dybas,
H. S. & M. Lloyd. 1962. Isolation by habitat in two synchronized species
of periodical cicadas. Ecology 43: 432-44. Elton,
C. 1927. Animal Ecology. Sedgwick & Jackson, Ltd., London. 207 p. Elton,
C. 1946. Competition and the structure of animal communities. J. Anim. Ecol.
15: 54-68. Elton,
C. S. 1958. The Ecology of Invasions by Animals and Plants. Methuen &
Co., Ltd. London 181 p. Elton,
C. S. & R. S. Miller. 1954. The ecological survey of animal communities,
with a practical system of classifying habitats by structural characters. J.
Ecol. 42: 460-96. Flanders,
S. E. 1958. Moranila californica as a usurped parasite of Saissetia
oleae. J. Econ. Ent. 50: 247-48. Flanders,
S. E. 1964. Some biological control aspects of taxonomy exemplified by the
genus Aphytis (Hymenoptera: Aphelinidae). Canad. Ent. 96: 888-93. Flanders,
S. E. 1965. Competition and cooperation among parasitic Hymenoptera related
to biological control. Canad. Ent. 97: 409-22. Flanders,
S. E. 1966. The circumstances of species replacement among parasitic
Hymenoptera. Canad. Ent. 98: 1099-24. Foott,
W. H. 1963. Competition between two species of mites. II. Factors influencing
intensity. Canad. Ent. 95: 45-57. Force,
D. C. 1972. r and K-strategists in endemic host-parasitoid communities. Bull.
Ent. Soc. Amer. 18: 135-37. Force,
D. C. & P. S. Messenger. 1968. The use of laboratory studies of three
hymenopterous parasites to evaluate field potential. J. Econ. Ent. 61:
1374-78. Frank,
P. W. 1957. Coactions in laboratory populations of two species of Daphnia.
Ecology 38: 510-19. Franz,
J. M. 1973a. Quantitative evaluation of natural enemy effectiveness.
Introductory review of the need for eavluation studies in relation to
integrated control. J. Appl. Ecol. 10: 321-23. Franz,
J. M. 1973b. The role of biological control in pest management. Bull. Lab.
Entomol. Agraria 30: 235-43. Furman,
D. P., R. D. Young & E. P. Catts. 1959. Hermetia illucens
(Linn.) as a factor in the natural control of Musca domestica
Linn. J. Econ. Ent. 52: 917-21. Forbes,
S. A. 1880. On some interactions of organisms. Bull. Ill. Nat. Hist. Surv. 1:
3-17. Gause,
G. F. 1934. The Struggle for Existence. William & Wilkins Co., Baltimore.
163 p. Gause,
G. F. & A. A. Witt. 1935. Behavior of mixed populations and the problem
of natural selection. Amer. Naturalist 69: 596-609. Gause,
G. F. 1936. The principles of biocoenology. Quart. Rev. Biol. 11: 320-36. Gilbert,
O., T. B. Reynoldson & J. Hobart. 1952. Gause's hypothesis: an
examination. J. Anim. Ecol. 21: 310-12. Gillies,
M. T. & A. Smith. 1960. The effect of a residual house spraying campaign
in East Africa on species balance in the Anopheles funestus
group. The replacement of A. funestus Giles by A. rivulorum
Leeson. Bull. Ent. Res. 51: 243-52. Goeden,
R. D. 1983. Critique and revision of Harris' scoring system for selection of
insect agents in biological control of weeds. Prof. Ecol. 5: 287-301. Goeden,
R. D. 1976. Biotic interference with insects imported for weed control. Ann.
Rev. Ent. 21: 325-42. Grinnell,
J. 1904. The origin and distribution of the chestnut backed chickadee. Auk
21: 364-82. Grinnell,
J. 1928. The presence and absence of animals. Univ. of Calif. Chronicle 30:
429-50 (Reprinted in: Joseph Grinnell's Philosophy of Nature; selected
writings of a western naturalist. Univ. of Calif. Press, Berkeley 1943. 237
p.) Hairston,
N. G. 1951. Interspecies competition and its probable influence upon the
vertical distribution of Appalachian salamanders of the genus Plethodon.
Ecology 32: 266-74. Hairston,
N. G. 1959. Species abundance and community organization. Ecology 40: 404-16. Hairston,
N. G. & S. L. Kellerman. 1965. Competition between varieties 2 and 3 of Paramecium
aurella: the influence of temperature in a food-limited system.
Ecology 46: 134-39. Hardin,
G. 1960. The competitive exclusion principle. Science 131(3409): 1292-97. Harper,
J. L., J. N. Clatworthy, I. H. McNaughton & G. R. Sagar. 1961. The
evolution and ecology of closely related species living in the same area.
Evolution 15: 209-27. Hartman,
W. D. 1957. Ecological niche differentiation in the boring sponges. Evolution
11: 294-97. Haskins,
C. P. & E. F. Haskins. 1965. Pheidole megacephala and Iridomyrmex
humilis in Bermuda--equilibrium or slow development? Ecology 46:
736-40. Hassell,
M. P. 1969a. A population model for the interaction between Cyzenis albicans
(Fall.) (Tachinidae) and Operophtera brumata (L.) (Geometridae)
at Wytham, Berkshire. J. Anim. Ecol. 38: 567-76. Hassell,
M. P. 1969b. A study of the mortality factors acting upon Cyzenis albicans
(Fall.), a tachinid parasite of the winter moth, Operophtera brumata
(L.). J. Anim. Ecol. 38: 329-39. Hassell,
M. P. 1978. The Dynamics of Arthropod Predator-Prey Systems. Princeton Univ.
Press, Princeton, New Jersey. Hassell,
M. P. 1980. Foraging strategies, population models and biological control: A
case study. J. Anim. Ecol. 49: 603-28. Heatwole,
H. & D. M. Davis. 1965. Ecology of three sympatric species of parasitic
insects of the genus Megarhyssa. Ecology 46: 140-50. Hokyo,
N. & K. Kiritani. 1963. Two species of egg parasites as contemporaneous
mortality factors in the egg population of the southern green stink bug, Nezara
viridula. Japan J. Appl. Zool. 3: 214-27. Holloway,
J. K. 1958. The biological control of the Klamath weed in California. Proc.
10th Intern. Congr. Ent., Montreal, 1956 4: 557-60. Huffaker,
C. P., P. S. Messenger & P. DeBach. 1971. The natural enemy component in
natural control and the theory of biological control. In:
"Biological Control," C. B. Huffaker (ed.), pp. 16-67. Plenum
Press. 511 p. Hughes,
R. D. et al. 1974. The selection of natural enemies for the biological
control of the Australian bushfly. J. Applied Ecol. 11: 483-88. [Addresses
the concept of pre-introductory evaluation for biological control of a native
pest]. Hurlbert,
S. H. 1975. Secondary effects of pesticides on aquatic ecosystems. San Diego
St. Univ. Center For Marine Studies, Contrib. No. 6. Springer-Verlag, New
York. p. 81-148. Hurlbert,
S. H. & M. S. Mulla. 1981. Hydrobiologia 83: 125-51. Hurlbert,
S. H., J. Zedler & D. Fairbanks. 1972. Ecosystem alteration by mosquito
fish (Gambusia affinis) predation. Science 175: 639-41. Hutchinson,
G. E. 1953. The concept of pattern in ecology. Proc. Acad. Nat. Sci., Phila.
105: 1-12. Hutchinson,
G. E. 1957. Concluding remarks. Cold Spring Harbor Symp. Quant. Biol. 22:
415-27. Hutchinson,
G. E. 1964. The lacustrine microcosm reconsidered. Amer. Scien. 52: 334-41. Hutchinson,
G. E. & E. S. Deevey, Jr. 1949. Ecological studies on populations. In:
"Survey of Biological Progress." Academic Press, N.Y. p. 325-59.
396 p. Kiritani,
K., N. Hokyo & J. Yukawa. 1963. Coexistence of the two related stink bugs
Nezara viridula and N. antennata under natural
conditions. Res. Pop. Ecol. 5: 11-22. Klomp,
H. 1961. The concepts "similar ecology" and "competition"
in animal ecology. Arch. Nederl. Zool. 14: 90-102. Kostitsin,
V. A. 1937. Biologie Mathematique. Librairie Armand Colin, Paris 223: 193 p. Kuenzler,
E. J. 1958. Niche relations of three species of lycosid spiders. Ecology 39:
494-500. Lack,
D. 1944. Ecological aspects of species formation in passerine birds. Ibis 86:
260-86. Laird,
M. 1959. Biological solutions to problems arising from the use of modern
insecticides in the field of public health. Acta Trop. 16: 331-55. 34.
Legner, E. F. 1966.
Competition among larvae of Hippelates
collusor (Diptera: Chloropidae) as
a natural control factor. J. Econ . Entomol. 59(6): 1315-1321. 64. Legner, E. F. 1970.
Attraction of Hippelates eye
gnats and other minute Diptera to baits and man with considerations on
competitive
displacement by exotic non-problem species. Proc. Calif. Mosq. Contr. Assoc., Inc. 37: 119-126. 216.
Legner, E. F. 1983.
Imported cichlid behaviour in California. Proc. Intern. Symp. on Tilapia
in aquaculture, Nazareth, Israel, 8-13 May,
1983. Tel Aviv Univ. Publ.
59-63. 226.
Legner, E. F. 1986a.
Importation of exotic natural enemies. In: pp. 19-30, "Biological Control of
Plant Pests and of Vectors of Human and
Animal Diseases." Fortschritte der Zool. Bd. 32: 341 pp. 227.
Legner, E. F. 1986b.
The requirement for reassessment of interactions among dung beetles,
symbovine flies and natural enemies. Entomol. Soc. Amer. Misc. Publ.
61: 120-131. 212.
Legner, E. F.
& F. W. Pelsue, Jr. 1983. Contemporary appraisal of the population
dynamics of introduced cichlid fish in south
California. Proc. Calif. Mosq.
& Vector Contr. Assoc., Inc. 51:
38-39. 217.
Legner, E. F.
& R. D. Sjogren. 1984. Biological mosquito control furthered by
advances in technology and research.
J. Amer. Mosq. Contr.
Assoc. 44(4): 449-456. Leslie,
P. H. & J. C. Gower. 1958. The properties of a stochastic model for two
competing species. Biometrika 45: 316-30. Lotka,
A. J. 1925. Elements of Physical Biology. Williams & Wilkins Co.,
Baltimore. 460 p. Luck,
R. F. 1985. Competitive exclusion of Aphytis lingnanensis by A.
melinus: potential role of host size. Ecology 66: 904-13. MacArthur,
R. H. 1958. Population ecology of some warblers of northeastern coniferous
forests. Ecology 39: 599-619. Mayr,
E. 1947. Ecological factors in speciation. Evolution 1: 163-88. Mayr,
E. 1948. The bearing of the new systematics on genetical problems. The nature
of species. Advan. Genet. 2: 205-37. Mayr,
E. 1966. Animal Species and Evolution. The Belnap Press of Harvard Univ.
Press, Cambridge, Mass. 797 p. McIntosh,
R. P. 1963. Ecosystems, evolution and relational patterns of living
organisms. Amer. Scien. 51: 246-67. Merrell,
J. J. 1951. Interspecific competition between Drosophila funebris
and Drosophila melanogaster. Amer. Naturalist 85: 159-69. Miller,
J. C. 1983. Ecological relationships among parasites and the practice of
biological control. Environ. Ent. 12: 620-24. Miller,
R. S. 1964a. Larval competition in Drosophila melanogaster and D.
simulans. Ecology 45: 132-48. Miller,
R. S. 1964b. Ecology and distribution of pocket gophers in Colorado. Ecology
45: 256-72. Mills,
N. J. 1983. Possibilities for the biological control of Choristoneura fumiferana
(Clemens) using natural enemies from Europe. Biocontrol News and Information
4: 103-25. [A preintroductory assessment of how to bring about classical
biological control of spruce budworm in its native home]. Milne,
A. 1961. Mechanisms in biological competition: definition of competition
among animals. Symp. Soc. Exptal. Biol. 15: 40-61. Moore,
J. A. 1952. Competition between Drosophila melanogaster and Drosophila
similans. I. Population cage experiments. Evolution 6: 407-20. Neyman,
J., T. Park & E. L. Scott. 1956. Struggle for existence: the Tribolium
model: biological and statistical aspects. Proc. Symp. Math. Statistics and
Probability, 3rd ed. Berkeley 4: 41-79. Nicholson,
A. J. 1933. The balance of animal populations. J. Anim. Ecol. 2: 132--. Nicholson,
A. J. 1957. The self-adjustment of populations to change. Cold Spring Harbor
Symp. Quant. Biol. 22: 153-72. Park,
T. 1948. Experimental studies of interspecies competition. I. Competition
between populations of the flour beetles, Tribolium confusum
Duval and Tribolium castaneum Herbst. Ecol. Monog. 18: 265-307. Park,
T. 1954. Experimental studies of interspecies competition. II. Temperature,
humidity and competition in two species of Tribolium. Physiol. Zool.
27: 177-238. Park,
T. 1955. Experimental competition in beetles, with some general implications.
In: "The Numbers of Man and Animals." p. 69-82. Oliver &
Boyd, Ltd., London. Park,
T. 1955. Ecological experimentation with animal populations. Sci. Monthly 81:
271-75. Park,
T. 1957. Experimental studies of interspecies competition. III. Relation of
initial species proportion to competitive outcome in populations of Tribolium.
Physiol. Zool. 30: 22-40. Park,
T. 1962. Beetles, competition and populations. Science 138: 1369-75. Park,
T., E. V. Gregg & C. Z. Lutherman. 1941. Studies in population
physiology. X. Interspecific competition in populations of granary beetles.
Physiol. Zool. 14: 395-430. Park,
T., P. H. Leslie & D. B. Mertz. 1964. Genetic strains and competition in
populations of Tribolium. Physiol. Zool. 37: 97-162. Patten,
B. D. 1961. Competitive exclusion. The exclusion principle is recast in the
context of a generalized scheme for interspecific interaction. Science
134(3490): 1599-1601. Patten,
B. C. 1964. Effects of radiation stress on interspecific competition. Oak
Ridge Natl. Lab., Radiation Ecol. Sect., Publ. No. 107: 104-8. Pemberton,
C. E. & H. F. Willard. 1918. Interrelations of fruit fly parasites in
Hawaii. J. Agric. Res. 12: 285-95. Polnik,
A. 1960. Effects of some intraspecies processes on competition between two
species of flour beetles, Latheticus oryzae and Tribolium
confusum. Physiol. Zool. 33: 42-57. Pontin,
A. J. 1960. Field experiments on colony foundation by Lasius niger
(L.) and L. flavus (F.). Insectes Sociaux 7(3): 227-30. Pontin,
A. J. 1961. Population stabilization and competition between the ants Lasius
flavus (F.) and L. niger (L.). J. Anim. Ecol. 30: 47-54. Pontin,
A. J. 1963. Further considerations of competition and the ecology of the ants
Lasius flavus (F.) and L. niger (L.). J. Anim.
Ecol. 32: 565-74. Price,
P. W. 1972. Methods of sampling and analysis for predictive resultsin the
introduction of entomophagous insects. Entomophaga 17: 211-22.
[Preintroductory evaluation based on niche parameters]. Remington,
C. L. 1968. Suture zones of hybrid interaction between recently joined
biotas. Evol. Biol. 2: 321-428. Richards,
O. W. 1963. Some factors controlling insect populations living on scotch
broom. Proc. 16th Intern. Congr. Zool., Wash., D.C. 3: 353-56. Rivnay,
E. 1964. Influence of man on insect ecology in arid zones. Ann. Rev. Ent. 9:
41-62. Ross,
H. H. 1957. Principles of natural coexistence indicated by leafhopper
populations. Evolution 11: 113-29. Savage,
J. M. 1958. The concept of ecological niches with reference to the theory of
natural coexistence. Evolution 12: 111-12. Schuster,
M. F. & H. A. Dean. 1976. Competitive displacement of Anagyrus antoninae
([Hym.: Encyrtidae] by its ecological homologue Neodusmetia sangwani
[Hym.: Encyrtidae]. Entomophaga 21: 127-30. Schwerdfeger,
F. 1942. Uber die Ursachen des Massenwechsels der Insekten. Z. angew. Ent.
28: 254-303. Simpson,
G. G. 1964. Organisms and molecules in evolution. Science 146(3651): 1535-38. Slobodkin,
L. B. 1962. Growth and regulation of Animal Populations. Holt, Rheinhart
& Winston, N.Y. 184 p. Smith,
H. S. 1929. Multiple parasitism: its relation to the biological control of
insect pests. Bull. Ent. Res. 20: 141-49. Solomon,
M. E. 1957. Dynamics of insect populations. Ann. Rev. Ent. 2: 121-42. Trujillo,
E. E. & G. E. Templeton. 1981. The use of plant pathogens in biological
control of weeds. In: D. Pimentel (ed.) Agric. Handbk. Ser: Integrated
Pest Management. Boca Raton, Florida. CRC Press, Inc. Turnbull,
A. L. 1967. Population dynamics of exotic insects. Bull. Ent. Soc. Amer. 13:
333-37. Udvardy,
M. D. F. 1951. The significance of interspecific competition in bird life.
Oikos 3: 98-123. Udvardy,
M. D. F. 1959. Notes on the ecological concepts of habitat biotype and niche.
Ecology 40: 725-28. Utida,
S. 1953. Interspecific competition between two species of bean weevil.
Ecology 34: 301-07. Utida,
S. 1957. Population fluctuation, an experimental and theoretical approach.
Cold Spring Harbor Symp. Quant. Biol. 22: 139-50. van
den Bosch, R. & F. H. Haramoto. 1953. Competition among parasites of the
oriental fruit fly. Proc. Hawaiian Ent. Soc. 15: 201-06. van
den Bosch, R., E. I. Schlinger, E. J. Dietrick, J. C. Hall & B. Puttler.
1964. Studies on succession, distribution and phenology of imported parasites
of Therioaphis trifolii (Monell) in southern California.
Ecology 45: 602-21. Van
Valen, L. 1960. Further competitive exclusion. Science 132(3440): 1674-75. Varley,
G. C. 1949. Special review: Population changes in German forest pests. J.
Anim. Ecol. 18: 117-22. Venkatraman,
T. V. 1964. Experimental studies in superparasitism and multiparasitism in Horogenes
cerophaga (Grav.) and Hymenobosmina rapi (Cam.), the
larval parasites of Plutella maculipennis (Curt.). Indian J.
Ent. 16: 1-32. Volterrra,
V. 1931. Variations and fluctuations of the number of individuals in animal
species living together [Trans. in "Animal Ecology." Chapman, p.
409-48 (1931).]. Weatherley,
A. H. 1963. Notions of niche and competition among animals with special
reference to freshwater fish. Nature 197(4862): 14-17. Whittaker,
R. H. 1965. Dominance and diversity in land plant communities. Numerical
relations of species express the importance of competition in community
function and evolution. Science 147(3655): 250-60. Williams,
C. B. 1947. The generic relations of species in small ecological communities.
J. Anim. Ecol. 16: 11-18. Williamson,
M. H. 1957. An elementary theory of interspecific competition. Nature 180:
422-25. Yoshida,
T. 1960. Adult longevity under the condition of interspecific competition.
Mem. Fac. Liberal Arts Educ. Miyasski Univ. 9: 463-72. Zimmerman, J. R. 1960. Seasonal population changes and
habitat preferences in the genus Laccophilus. Ecology 41: 141-52. |