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T. White (1984)
The abundance of invertebrate herbivores in relation to the availability of nitrogen in stressed food plantsOecologia, 63
F. Maxwell, P. Jennings (1981)
Breeding plants resistant to insects
P. Morrow, V. Lamarche (1978)
Tree Ring Evidence for Chronic Insect Suppression of Productivity in Subalpine EucalyptusScience, 201
P. Morrow, T. Whitham, B. Potts, P. Ladiges, D. Ashton, Jb Williams (1994)
Gall-forming insects concentrate on hybrid phenotypes of Eucalyptus hosts
V. Brown, R. Fritz, E. Simms (1993)
Plant Resistance to Herbivores and Pathogens.Journal of Ecology, 81
N. Moran (1991)
PHENOTYPE FIXATION AND GENOTYPIC DIVERSITY IN THE COMPLEX LIFE CYCLE OF THE APHID PEMPHIGUS BETAEEvolution, 45
S. O’Brien, E. Mayr (1991)
Bureaucratic mischief: recognizing endangered species and subspecies.Science, 251 4998
J. Aguilar, W. Boecklen (1992)
Patterns of herbivory in the Quercus grisea X Quercus gambelii species complexOikos, 64
D. Drake (1981)
Reproductive success of two Eucalyptus Hybrid populations. I. generalized seed output model and comparison of fruit parametersAustralian Journal of Botany, 29
T. Whitham, P. Morrow, Bradley Potts (1991)
Conservation of hybrid plants.Science, 254 5033
A. Mitton, M. Grant (1984)
Associations Among Protein Heterozygosity, Growth Rate, and Developmental HomeostasisAnnual Review of Ecology, Evolution, and Systematics, 15
W. Lewis (1980)
Polyploidy : biological relevance
J. Bunce, B. Chabot, L. Miller (1979)
Role of Annual Leaf Carbon Balance in the Distribution of Plant Species along an Elevational GradientBotanical Gazette, 140
A. Griffin, I. Burgess, L. Wolf (1988)
Patterns of natural and manipulated hybridisation in the genus Eucalyptus L'Hérit. - a review.Australian Journal of Botany, 36
R. Fritz, C. Nichols-orians, S. Brunsfeld (1994)
Interspecific hybridization of plants and resistance to herbivores: hypotheses, genetics, and variable responses in a diverse herbivore communityOecologia, 97
M. Rojas (1992)
The Species Problem and Conservation: What are We Protecting?Conservation Biology, 6
T. Dowling, B. DeMarais, W. Minckley, M. Douglas, P. Marsh (1992)
Use of Genetic Characters in Conservation BiologyConservation Biology, 6
K. Paige, W. Capman (1993)
THE EFFECTS OF HOST‐PLANT GENOTYPE, HYBRIDIZATION, AND ENVIRONMENT ON GALL‐APHID ATTACK AND SURVIVAL IN COTTONWOOD: THE IMPORTANCE OF GENETIC STUDIES AND THE UTILITY OF RFLPSEvolution, 47
K. Floate, Michael Kearsley, T. Whitham (1993)
Elevated herbivory in plant hybrid zones: Chrysomela confluens, populus and phenological sinksEcology, 74
L. Heaney, R. Timm (1985)
Morphology, genetics, and ecology of pocket gophers (genus Geomys) in a narrow hybrid zoneBiological Journal of The Linnean Society, 25
N. Moran, T. Whitham (1988)
EVOLUTIONARY REDUCTION OF COMPLEX LIFE CYCLES: LOSS OF HOST‐ALTERNATION IN PEMPHIGUS (HOMOPTERA: APHIDIDAE)Evolution, 42
L. Fox, P. Morrow (1983)
Estimates of damage by herbivorous insects on Eucalyptus treesAustral Ecology, 8
B. Potts, J. Reid (1985)
Analysis of a Hybrid Swarm Between Eucalyptus risdonii Hook. F. And E. amygdalina LabillAustralian Journal of Botany, 33
T. White (1969)
An index to measure weather-induced stress of trees associated with outbreaks of Psyllids in AustraliaEcology, 50
J. Rattenbury (1962)
CYCLIC HYBRIDIZATION AS A SURVIVAL MECHANISM IN THE NEW ZEALAND FOREST FLORAEvolution, 16
Paul Keim, Ken Paige, Thomas Whitham, Karl Lark (1989)
Genetic analysis of an interspecific hybrid swarm of Populus: occurrence of unidirectional introgression.Genetics, 123 3
J. Wendel, J. Stewart, J. Rettig (1991)
MOLECULAR EVIDENCE FOR HOMOPLOID RETICULATE EVOLUTION AMONG AUSTRALIAN SPECIES OF GOSSYPIUMEvolution, 45
R. Sage, D. Heyneman, K. Lim, A. Wilson (1986)
Wormy mice in a hybrid zoneNature, 324
P. Kat (1985)
HISTORICAL EVIDENCE FOR FLUCTUATION IN LEVELS OF HYBRIDIZATIONEvolution, 39
R. Fritz, E. Simms (1992)
Botanical Defenses. (Book Reviews: Plant Resistance to Herbivores and Pathogens. Ecology, Evolution, and Genetics.)Science
L. Pryor, L. Johnson (1972)
A classification of the Eucalypts
L. Ericson, J. Burdon, A. Wennström (1993)
Inter-specific host hybrids and phalacrid beetles implicated in the local survival of smut pathogensOikos, 68
J. Barker (1990)
Sunflower trichome defenses avoided by a sunflower stem weevil, Cylindrocopturus adspersus LeConte (Coleoptera: Curculionidae).Journal of the Kansas Entomological Society, 63
D. Valentine, G. Stebbins (1951)
Variation and Evolution in Plants
G. Stebbins (1971)
Chromosomal evolution in higher plants
L. Fox, P. Morrow (1986)
On comparing herbivore damage in Australian and north temperate systemsAustral Ecology, 11
M. McClure (1985)
Patterns of Abundance, Survivorship, and Fecundity of Nuculaspis tsugae (Homoptera: Diaspididae) on Tsuga Species in Japan in Relation to ElevationEnvironmental Entomology, 14
L. Rieseberg (1991)
Homoploid reticulate evolution in Helianthus (Asteraceae): evidence from ribosomal genesAmerican Journal of Botany, 78
B. Potts (1986)
Population dynamics and regeneration of a hybrid zone between Eucalyptus risdonii Hook. f. and E. amygdalina Labill.Australian Journal of Botany, 34
P. Brussard (1984)
Geographic Patterns and Environmental Gradients: The Central-Marginal Model in Drosophila RevisitedAnnual Review of Ecology, Evolution, and Systematics, 15
B. Potts, J. Reid (1988)
HYBRIDIZATION AS A DISPERSAL MECHANISMEvolution, 42
W. Boecklen, R. Spellenberg (1990)
Structure of herbivore communities in two oak (Quercus spp.) hybrid zonesOecologia, 85
D. Levin (1983)
Polyploidy and Novelty in Flowering PlantsThe American Naturalist, 122
F. Dupont, A. Crivelli (1988)
Do parasites confer a disadvantage to hybrids?Oecologia, 75
P. Morrow, L. Fox (1989)
Estimates of Pre‐Settlement Insect Damage in Australian and North American ForestsEcology, 70
T. White (1976)
Weather, food and plagues of locustsOecologia, 22
T. Whitham (1989)
Plant Hybrid Zones as Sinks for PestsScience, 244
M. Head, C. Lacey (1988)
Radiocarbon Age-Determinations From LignotubersAustralian Journal of Botany, 36
T. Uyeno, Gerald Smith (1972)
Tetraploid Origin of the Karyotype of Catostomid FishesScience, 175
R. Lewontin, R. Lewontin, L. Birch, L. Birch (1966)
HYBRIDIZATION AS A SOURCE OF VARIATION FOR ADAPTATION TO NEW ENVIRONMENTSEvolution, 20
K. Floate, T. Whitham (1994)
Aphid-ant interaction reduces chrysomelid herbivory in a cottonwood hybrid zoneOecologia, 97
K. Floate, T. Whitham (1993)
The "Hybrid Bridge" Hypothesis: Host Shifting via Plant Hybrid SwarmsThe American Naturalist, 141
T. Dowling, B. DeMarais (1993)
Evolutionary significance of introgressive hybridization in cyprinid fishesNature, 362
We found the hybrid zone between Eucalyptus amygdalina and Eucalyptus risdonii to be a center of insect and fungal species richness and abundance. Of 40 taxa examined, 73% were significantly more abundant in the hybrid zone than in pure zones, 25% showed on significant differences, and 2% were most abundant on a pure host species. The average hybrid tree supported 53% more insect and fungal species, and relative abundances were, on average, 4 times greater on hybrids than on either eucalypt species growing in pure stands. Hybrids may act as refugia for rare species: 5 of 40 species were largely restricted to the hybrid zone. Also, 50% of the species coexisted only in the hybrid zone, making for mique species assemblages. Although hybrids support more species and greater abundances, all hybrids are not equal: 68% of the 40 taxa examined were significantly more abundant on one hybrid phenotype than another. While herbivore concentrations on F1 type intermediates were rare, concentrations were common on phenotypes resembling backcrosses either to E. amygdalina or E. risdonii . For specialist herbivores, the hybrid phenotype most heavily utilized appears to be determined by its phenotypic affinity to its host species. Generalists exhibit an overall greater abundance on hybrids, but are less likely to utilize one hybrid phenotype over another. Mechanistic explanations for these distributions are numerous and probably species specific, but are likely to include: increased genetic susceptibility of hybrids due to hybrid breakdown; increased stress in the hybrid zone resulting in greater plant susceptibility; and a greater diversity of resources in the hybrid zone which could support more species. Seed capsule production by hybrids and their parental species is negatively correlated with herbivory. However, it is difficult to determine whether herbivores cause this pattern as hybrids may have inherently lower sexual reproduction. Laws enacted to protect rare and endangered species do not include hybrids. We argue that a re-examination of our current “hybrid policy” is warranted. Plant hybrid zones are centers of plant evolution and speciation, sources of economically important plants and potential biocontrol agents, and, as our study suggests, also provide essential habitats for phytophagous communities.
Oecologia – Springer Journals
Published: May 1, 1994
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