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Izzo TJ, Fernandez Piedade MT, Dáttilo W. Postponing the production of ant domatia as a strategy promoting an escape from flooding in an Amazonian myrmecophyte. ANNALS OF BOTANY 2018; 122:985-991. [PMID: 29878049 PMCID: PMC6266100 DOI: 10.1093/aob/mcy098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/13/2018] [Indexed: 06/08/2023]
Abstract
Background and Aims Even when adapted to flooding environments, the spatial distribution, growing strategies and anti-herbivore defences of plants face stressful conditions. Here we describe the effects of flooding on carbon allocation on growth, domatia and leaf production, and the herbivory on the myrmecophyte domatia-bearing Tococa coronata Benth. (Melastomataceae) growing along river banks in the Amazon region. Methods In an area of 80 000 m2 of riparian forest along the Juruena River we actively searched for individuals of T. coronata. In each plant we evaluated the size of the plant when producing the first domatium and determined its best predictor: (1) plant total height; (2) size of plants above flood level; or (3) length of time each plant spent underwater. We also compared the herbivory, internode elongation, foliar asymmetry and specific leaf weight between T. coronata individuals growing above and below the maximum flooding level. The distance to the river and the height of the first domatium produced were compared between T. coronata and its sympatric congener, T. bulifera. Key Results We found that T. coronata invests in rapid growth in the early ontogenetic stages through an elongation of internodes rather than in constitutive anti-herbivore defences to leaves or domatia to exceed the maximum flooding level. Consequently, its leaf herbivory was higher when compared with those produced above the flooding level. Individuals with leaves above flood levels produce coriaceous leaves and ant-domatias. Thus, flooding seems to trigger changes in growth strategies of the species. Furthermore, T. coronata occurs within the flood level, whereas its congener T. bullifera invariably occurs at sites unreachable by floods. Conclusion Even in conditions of high stress, T. coronata presents both physiological and adaptive strategies that allow for colonization and establishment within flooded regions. These mechanisms involve an extreme trade-off of postponing adult plant characteristics to rapid growth to escape flooding while minimizing carbon allocation to defence.
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Affiliation(s)
- Thiago J Izzo
- Departamento de Botânica e Ecologia, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso, CEP, Brazil
| | - Maria Teresa Fernandez Piedade
- Departamento de Biologia Aquática e Limnologia, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, CEP, Brazil
| | - Wesley Dáttilo
- Red de Ecoetología, Instituto de Ecología AC, Xalapa, Veracruz, Mexico
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Duarte L, Viejo RM. Environmental and phenotypic heterogeneity of populations at the trailing range-edge of the habitat-forming macroalga Fucus serratus. MARINE ENVIRONMENTAL RESEARCH 2018; 136:16-26. [PMID: 29478764 DOI: 10.1016/j.marenvres.2018.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 02/03/2018] [Accepted: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Empirical work on the dynamics of range limits of species distributions often lack replications of edge populations. We compared the local environment and performance of two groups of geographically peripheral populations of the foundation intertidal alga Fucus serratus L. at its southern range boundary in the NW Iberian Peninsula. Two populations were located on the Western Galician coast in large embayments or rias, and the other two on a Northern open coastal stretch in Lugo province. Sharp differences were detected in the local environment and performance of the two groups of populations. While recruitment was quite consistent throughout the year in rias, it was very limited and variable in Lugo. Furthermore, thalli from rias were severely damaged following their transplantation in Lugo, and poor conditions of local adult plants were detected there in subsequent years. These results suggest a higher vulnerability of Lugo populations under new climate conditions, while western rias, strongly influenced by upwelling events, feasibly act as contemporary refugia for this species. If sustained over time, these refugia may mitigate the retreat of the seaweed' rear-edge predicted by large spatial scale models.
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Affiliation(s)
- Linney Duarte
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, E-28933 Móstoles, Madrid, Spain
| | - Rosa M Viejo
- Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, E-28933 Móstoles, Madrid, Spain.
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Copper Contamination Impairs Herbivore Initiation of Seaweed Inducible Defenses and Decreases Their Effectiveness. PLoS One 2015; 10:e0135395. [PMID: 26274491 PMCID: PMC4537182 DOI: 10.1371/journal.pone.0135395] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/21/2015] [Indexed: 11/19/2022] Open
Abstract
Seaweed-herbivore interactions are often mediated by environmental conditions, yet the roles of emerging anthropogenic stressors on these interactions are poorly understood. For example, chemical contaminants have unknown consequences on seaweed inducible resistance and herbivore response to these defenses despite known deleterious effects of contaminants on animal inducible defenses. Here, we investigated the effect of copper contamination on the interactions between a snail herbivore and a brown seaweed that displays inducible resistance to grazing. We examined seaweed inducible resistance and its effectiveness for organisms exposed to copper at two time points, either during induction or after herbivores had already induced seaweed defenses. Under ambient conditions, non-grazed tissues were more palatable than grazed tissues. However, copper additions negated the preference for non-grazed tissues regardless of the timing of copper exposure, suggesting that copper decreased both how herbivores initiated these inducible defenses and their subsequent effectiveness. Copper decreased stimulation of defenses, at least in part, by suppressing snail grazing pressure—the cue that turns inducible defenses on. Copper decreased effectiveness of defenses by preventing snails from preferentially consuming non-grazed seaweed. Thus, contaminants can potentially stress communities by changing seaweed-herbivore interactions mediated via inducible defenses. Given the ubiquity of seaweed inducible resistance and their potential influence on herbivores, we hypothesize that copper contamination may change the impact of these resistant traits on herbivores.
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Williams SL, Bracken MES, Jones E. Additive effects of physical stress and herbivores on intertidal seaweed biodiversity. Ecology 2013; 94:1089-101. [DOI: 10.1890/12-0401.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Aumack CF, Amsler CD, McClintock JB, Baker BJ. IMPACTS OF MESOGRAZERS ON EPIPHYTE AND ENDOPHYTE GROWTH ASSOCIATED WITH CHEMICALLY DEFENDED MACROALGE FROM THE WESTERN ANTARCTIC PENINSULA: A MESOCOSM EXPERIMENT(1). JOURNAL OF PHYCOLOGY 2011; 47:36-41. [PMID: 27021708 DOI: 10.1111/j.1529-8817.2010.00927.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It has been hypothesized that the extensive mesograzer community along the western Antarctic Peninsula regulates epiphytic algae as well as emergent filaments from endophytic species. Should grazing limit growth of fouling or potentially pathogenic microphytes, then Antarctic macrophytes may actually benefit from the remarkably high densities of mesograzer amphipods that occur in these waters. Although initially counterintuitive, the negative impacts of epi/endophyte fouling may outweigh stresses caused by limited amphipod grazing on chemically defended macrophytes by reducing stress from endo/epiphyte biomass. If so, then alleviating mesograzing stress should result in significant increases in endo/epiphytic biomass. To test this hypothesis, a mesocosm experiment was conducted. Individuals representing four common species of Antarctic macroalgae were placed in flow-through seawater mesocosms. Amphipods were added to five mesocosms at simulated natural densities, while the other five remained herbivore free. At the end of 7 weeks, endo/epiphytic growth on individual macrophytes was quantified. Most species of macroalgae demonstrated noticeably higher instances of endophyte coverage, epiphytic diversity, and diatom colonization in consumer-free mesocosms than in the presence of amphipods. These data suggest that macroalgae along the western Antarctic Peninsula rely on grazers to control populations of potentially harmful epiphytes. We hypothesize that the chemically defended macroalgal flora lives in mutualism with high densities of mesograzers, providing amphipods with shelter from predation while continually being cleaned of potentially harmful endo/epiphytes.
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Affiliation(s)
- Craig F Aumack
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294-1170, USADepartment of Chemistry, University of South Florida, Tampa, Florida 33620, USA
| | - Charles D Amsler
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294-1170, USADepartment of Chemistry, University of South Florida, Tampa, Florida 33620, USA
| | - James B McClintock
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294-1170, USADepartment of Chemistry, University of South Florida, Tampa, Florida 33620, USA
| | - Bill J Baker
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294-1170, USADepartment of Chemistry, University of South Florida, Tampa, Florida 33620, USA
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Sotka EE, Forbey J, Horn M, Poore AGB, Raubenheimer D, Whalen KE. The emerging role of pharmacology in understanding consumer–prey interactions in marine and freshwater systems. Integr Comp Biol 2009; 49:291-313. [DOI: 10.1093/icb/icp049] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
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Sotka EE, Giddens H. Seawater temperature alters feeding discrimination by cold-temperate but not subtropical individuals of an ectothermic herbivore. THE BIOLOGICAL BULLETIN 2009; 216:75-84. [PMID: 19218494 DOI: 10.1086/bblv216n1p75] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Seawater temperature varies across multiple spatial and temporal scales, yet the roles that such variation play in altering biotic interactions are poorly known. We assessed temperature-mediated feeding behavior exhibited by the herbivorous amphipod Ampithoe longimana collected from cold-temperate and subtropical estuaries (27 degrees N and 41 degrees N, respectively). Individuals were offered a pairwise feeding choice between lyophilized seaweeds that provide higher fitness (Ulva intestinalis) or lower fitness (Halimeda tuna, H. opuntia, Amphiroa spp., or Stypopodium zonale). Overall, herbivores preferentially consumed the higher quality U. intestinalis more than any lower quality food. However, the strength of this feeding choice was not consistent. Northern herbivores consumed proportionally more poorer quality tissue at 25 degrees C than at 20 degrees C in two assays (H. opuntia and Amphiroa sp.), consumed less poorer quality tissue at 25 degrees C than at 20 degrees C in one assay (S. zonale), and showed no difference in another assay (H. tuna). Moreover, when offered tissue coated with lipophilic extracts of H. opuntia, northern herbivores consumed more extract-coated tissue at 25 degrees C than at 20 degrees C. In contrast to northern herbivores, the southern herbivores did not alter their feeding choices with temperature. This study represents the first demonstration that short-term (i.e., days-long) variation in ambient temperature alters feeding choices in a marine herbivore.
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Affiliation(s)
- Erik E Sotka
- Grice Marine Laboratory and Department of Biology, College of Charleston, 205 Fort Johnson Road, Charleston, South Carolina 29412, USA.
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Long JD, Hamilton RS, Mitchell JL. Asymmetric competition via induced resistance: specialist herbivores indirectly suppress generalist preference and populations. Ecology 2007; 88:1232-40. [PMID: 17536409 DOI: 10.1890/06-1585] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Species may compete indirectly by altering the traits of a shared resource. For example, herbivore-induced responses in plants may make plants more resistant or susceptible to additional herbivorous insect species. Herbivore-induced plant responses can significantly affect interspecific competition and herbivore population dynamics. These herbivore-herbivore indirect interactions have been overlooked in aquatic ecosystems where previous studies used the same herbivore species to induce changes and to assess the effects of these changes. We asked whether seaweed grazing by one of two herbivorous, congeneric snail species (Littorina obtusata or Littorina littorea) with different feeding strategies and preferences would affect subsequent feeding preferences of three herbivore species (both snails and the isopod Idotea baltica) and population densities of three herbivore species (both snails and a third periwinkle snail, Lacuna vincta). In addition, we measured phlorotannin concentrations to test the hypothesis that these metabolites function as induced defenses in the Phaeophyceae. Snail herbivory induced cue-specific responses in apical tissues of the seaweed Fucus vesiculosus that affected the three herbivore species similarly. When compared to ungrazed controls, direct grazing by Littorina obtusata reduced seaweed palatability by at least 52% for both snail species and the isopod species. In contrast, direct grazing by L. littorea did not decrease seaweed palatability for any herbivore, indicating herbivore-specific responses. Previous grazing by L. obtusata reduced populations of L. littorea on outplanted seaweeds by 46% but had no effect on L. obtusata populations. Phlorotannins, a potential class of inducible chemicals in brown algae, were not more concentrated in grazed seaweed tissues, suggesting that some other trait was responsible for the induced resistance. Our results indicate that marine herbivores may compete via inducible responses in shared seaweeds. These plant-mediated interactions were asymmetric with a specialist (L. obtusata) competitively superior to a generalist (L. littorea).
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Affiliation(s)
- Jeremy D Long
- Marine Science Center, Northeastern University, 430 Nahant Road, Nahant, Massachusetts 01908, USA.
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Dethier MN, Williams SL, Freeman A. SEAWEEDS UNDER STRESS: MANIPULATED STRESS AND HERBIVORY AFFECT CRITICAL LIFE-HISTORY FUNCTIONS. ECOL MONOGR 2005. [DOI: 10.1890/03-4108] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Goranson CE, Ho CK, Pennings SC. Environmental gradients and herbivore feeding preferences in coastal salt marshes. Oecologia 2004; 140:591-600. [PMID: 15252727 DOI: 10.1007/s00442-004-1615-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Accepted: 05/14/2004] [Indexed: 11/27/2022]
Abstract
Current theories of plant-herbivore interactions suggest that plants may differ in palatability to herbivores as a function of abiotic stress; however, studies of these theories have produced mixed results. We compared the palatability of eight common salt marsh plants that occur across elevational and salinity stress gradients to six common leaf-chewing herbivores to determine patterns of plant palatability. The palatability of every plant species varied across gradients of abiotic stress in at least one comparison, and over half of the comparisons indicated significant differences in palatability. The direction of the preferences, however, was dependent on the plant and herbivore species studied, suggesting that different types of stress affect plants in different ways, that different plant species respond differently to stress, and that different herbivore species measure plant quality in different ways. Overall, 51% of the variation in the strength of the feeding preferences could be explained by a knowledge of the strength of the stress gradient and the type of gradient, plant and herbivore studied. This suggests that the prospects are good for a more complex, conditional theory of plant stress and herbivore feeding preferences that is based on a mechanistic understanding of plant physiology and the factors underlying herbivore feeding preferences.
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Affiliation(s)
- Carol E Goranson
- Warnell School of Forest Resources, University of Georgia, Athens, GA 30602, USA
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Taylor RB, Lindquist N, Kubanek J, Hay ME. Intraspecific variation in palatability and defensive chemistry of brown seaweeds: effects on herbivore fitness. Oecologia 2003; 136:412-23. [PMID: 12759815 DOI: 10.1007/s00442-003-1280-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Accepted: 04/02/2003] [Indexed: 10/26/2022]
Abstract
When offered a choice between brown seaweeds (Phaeophyta) from shallow inshore populations versus deeper offshore populations along the mid-Atlantic coast of the United States of America, the herbivorous amphipod Ampithoe longimana consistently preferred plants from the inshore populations. This was the case for three species (Dictyota menstrualis, Spatoglossum schroederi, and Sargassum filipendula) collected from each of a single inshore and offshore site, and for one species (D. menstrualis) collected from each of three inshore and three offshore sites. Bioassay-guided fractionation of chemical crude extracts from D. menstrualis suggested that the relative unpalatability of the offshore plants was due to the lipid-soluble secondary metabolites 4beta-hydroxydictyodial A and 18, O-dihydro-4beta-hydroxydictyodial A 18-acetate, along with minor compounds that were not fully identified. The inshore-offshore pattern did not appear to result from induction of defenses due to herbivory by mesograzers, as mesograzer densities were higher on the more palatable inshore plants. Herbivore feeding preferences for inshore versus offshore seaweeds matched the effects of those seaweeds on their fitness. When juvenile amphipods were raised on inshore versus offshore tissues of D. menstrualis, amphipod survivorship, growth, and ovulation were significantly suppressed on the offshore compared to the inshore tissues. Few previous investigations have studied intraspecific variance in seaweed palatability. We extend these by showing that between-population differences in palatability can persist for several years and by demonstrating that this variance is chemically based and has dramatic effects on herbivore fitness.
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Affiliation(s)
- Richard B Taylor
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3431 Arendell Street, Morehead City, NC 28557, USA
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Pennings SC, Carefoot TH, Zimmer M, Danko JP, Ziegler A. Feeding preferences of supralittoral isopods and amphipods. CAN J ZOOL 2000. [DOI: 10.1139/z00-143] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the feeding preferences of 3 supralittoral crustacean species in the Pacific Northwest of North America. The isopod Ligia pallasii (Brandt, 1833), the rocky-shore amphipod Traskorchestia traskiana (Stimpson, 1857), and the sandy-beach amphipod Megalorchestia californiana (Brandt, 1851) had similar feeding preferences, suggesting that feeding preferences were based on general algal traits rather than on adaptations particular to specific herbivores. No single trait clearly distinguished low- and high-preference seaweeds, although pH and phenolic compounds may have been important for two chemically defended seaweeds (Desmarestia sp. and Fucus sp., respectively). Feeding preferences of L. pallasii were affected by dietary history, but effects were minor compared with differences among seaweeds. All 3 consumers tended to prefer wrack (aged, stranded seaweeds) over fresh seaweeds of the same species. Our results suggested that increased organic and mineral contents of wrack were important in mediating these preferences, but that toughness and salt and nitrogen contents were not. Reduced levels of defensive compounds may have made wrack more palatable than fresh seaweeds in the case of the two chemically defended seaweeds.
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Stachowicz JJ, Hay ME. Geographic Variation in Camouflage Specialization by a Decorator Crab. Am Nat 2000; 156:59-71. [PMID: 10824021 DOI: 10.1086/303366] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In North Carolina, the decorator crab Libinia dubia camouflages almost exclusively with the chemically noxious alga Dictyota menstrualis. By placing this alga on its carapace, the crab behaviorally sequesters the defensive chemicals of the plant and gains protection from omnivorous consumers. However, Dictyota is absent north of North Carolina, whereas Libinia occurs as far north as New England. Crabs from three northern locations where Dictyota is absent (Rhode Island, Connecticut, and New Jersey) camouflaged to match their environment, rather than selectively accumulating any one species. When D. menstrualis was offered to crabs from northern sites, they did not distinguish between it and other seaweeds for camouflage, whereas crabs from Alabama and two locations in North Carolina used D. menstrualis almost exclusively. In addition, in winter and spring, when Dictyota was seasonally absent in North Carolina, Libinia selectively camouflaged with the sun sponge Hymeniacidon heliophila, which was chemically unpalatable to local fishes. Thus, southern crabs were consistent specialists on chemically defended species for camouflage, while northern crabs were more generalized. The geographic shift in crab behavior away from specialization coincides with a reported decrease in both total predation pressure and the frequency of omnivorous consumers. These shifts in the nature and intensity of predation pressure may favor different camouflage strategies (generalist vs. specialist), contributing to the observed geographic differences in camouflage behavior.
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Hoy CW, Head GP, Hall FR. Spatial heterogeneity and insect adaptation to toxins. ANNUAL REVIEW OF ENTOMOLOGY 1998; 43:571-594. [PMID: 15012398 DOI: 10.1146/annurev.ento.43.1.571] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Behavioral responses of insect herbivores to toxins are examined in managed and natural systems with reference to two important but largely ignored factors: heterogeneity in toxin distributions and the nature of the relationship between behavioral responses and physiological adaptation to the same toxins. Heterogeneous toxin distributions, which provide the opportunity for behavioral responses, are ubiquitous in managed and natural systems. Insect herbivores have evolved a wide variety of behavioral responses to such toxins. The nature of behavioral responses reflects toxin apparency, mode of action, and the extent to which sublethal effects influence behavior. The interaction between these behavioral responses to heterogeneously distributed toxins and physiological mechanisms of tolerance has influenced the evolution of insecticide resistance in managed systems and the evolution of plant defensive strategies in natural systems. An understanding of this interaction could lead to more evolutionarily stable methods of crop protection.
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Affiliation(s)
- C W Hoy
- Department of Entomology, Ohio Agricultural Research and Development Center, Wooster, Ohio 44691-4096, USA.
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Facultative mutualism between an herbivorous crab and a coralline alga: advantages of eating noxious seaweeds. Oecologia 1996; 105:377-387. [DOI: 10.1007/bf00328741] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/1995] [Accepted: 09/11/1995] [Indexed: 10/26/2022]
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Associational resistance and shared doom: effects of epibiosis on herbivory. Oecologia 1995; 102:329-340. [DOI: 10.1007/bf00329800] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/1994] [Accepted: 12/23/1994] [Indexed: 10/26/2022]
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Hunter MD, Schultz JC. Induced plant defenses breached? Phytochemical induction protects an herbivore from disease. Oecologia 1993; 94:195-203. [DOI: 10.1007/bf00341317] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/1992] [Accepted: 02/09/1993] [Indexed: 10/26/2022]
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Outbreaks of the winter moth on Sitka Spruce in Scotland are not influenced by nutrient deficiencies of trees, tree budburst, or pupal predation. Oecologia 1991; 86:62-69. [PMID: 28313159 DOI: 10.1007/bf00317390] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/1990] [Accepted: 09/17/1990] [Indexed: 10/26/2022]
Abstract
Since the early 1980s, the winter moth, Operophtera brumata L. (Lepidoptera: Geometridae) has emerged as a serious pest of Sitka Spruce, Picea sitchensis Bong. plantations in southern Scotland. Outbreaks are characterised by susceptible sites within plantations which can occur immediately adjacent to resistant sites. We investigated the level of some nutrients in the trees, the date of budburst of the trees, and the numbers of some potential predators of winter moth pupae. None could satisfactorily explain outbreak patterns. Although foliage analysis demonstrated that many trees were marginal or deficient in phosphorus, nitrogen and potassium, these deficiencies were not related to the susceptibility of a site. Within sites, the numbers and weights of O. brumata were positively related to phosphorus content and negatively related to calcium content of foliage. Other evidence suggests, however, that these correlations may not represent direct effects of phosphorus and calcium on larval growth and survival. Date of budburst, which commonly determines susceptibility of deciduous hosts to O. brumata, was unrelated to density, and pupal predators were more, not less, abundant in susceptible sites. Although it is difficult to distinguish between factors that initiate outbreaks and those that maintain them, these data suggest that nutrient deficiencies of trees, budburst date, and the distribution of pupal predators of the winter moth cannot explain patterns of outbreak of the winter moth on spruce.
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