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Kasey E. Barton - One of the best experts on this subject based on the ideXlab platform.
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Prickly Poppies Can Get Pricklier: Ontogenetic Patterns in the Induction of Physical Defense Traits
2016Co-Authors: Ryan P. Hoan, Rhys A. Ormond, Kasey E. BartonAbstract:Plant ontogeny is a common source of variation in Defense and herbivory. Yet, few studies have investigated how the induction of Physical Defense traits changes across plant ontogeny. Physical Defense traits are costly to produce, and thus, it was predicted that induction as a cost-saving strategy would be particularly favorable for seedlings, leading to ontogenetic declines in the inducibility of these traits. We tested for induction of three different Physical Defense traits (prickles, latex and leaf toughness) in response to mechanical defoliation and jasmonic acid application using prickly poppies (Argemone glauca and A. mexicana, Papaveraceae) as a model system. Genetic variation in the induction of Physical Defenses was tested using maternal sib-ships sampled from multiple populations. Both species induced higher densities of laminar prickles, although the magnitude of induction was much higher in the endemic Hawaiian prickly poppy, A. glauca, than in the cosmopolitan A. mexicana. The magnitude of prickle induction was also higher in young compared to older juvenile plant stages in A. glauca, demonstrating a strong role of ontogeny. Neither latex exudation nor leaf toughness was induced in either species. Although significant genetic variation was detected within and among populations for constitutive expression of Physical Defense traits in Argemone, there was no evidence for genetic variation in the induction of these traits. This study provides the first evidence for the induction of Physical Defenses in prickly poppies, emphasizing how an ontogenetically explicit framework can reveal new insights into plant Defense. Moreover, this study illustrates how siste
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prickly poppies can get pricklier ontogenetic patterns in the induction of Physical Defense traits
PLOS ONE, 2014Co-Authors: Ryan P. Hoan, Rhys A. Ormond, Kasey E. BartonAbstract:Plant ontogeny is a common source of variation in Defense and herbivory. Yet, few studies have investigated how the induction of Physical Defense traits changes across plant ontogeny. Physical Defense traits are costly to produce, and thus, it was predicted that induction as a cost-saving strategy would be particularly favorable for seedlings, leading to ontogenetic declines in the inducibility of these traits. We tested for induction of three different Physical Defense traits (prickles, latex and leaf toughness) in response to mechanical defoliation and jasmonic acid application using prickly poppies (Argemone glauca and A. mexicana, Papaveraceae) as a model system. Genetic variation in the induction of Physical Defenses was tested using maternal sib-ships sampled from multiple populations. Both species induced higher densities of laminar prickles, although the magnitude of induction was much higher in the endemic Hawaiian prickly poppy, A. glauca, than in the cosmopolitan A. mexicana. The magnitude of prickle induction was also higher in young compared to older juvenile plant stages in A. glauca, demonstrating a strong role of ontogeny. Neither latex exudation nor leaf toughness was induced in either species. Although significant genetic variation was detected within and among populations for constitutive expression of Physical Defense traits in Argemone, there was no evidence for genetic variation in the induction of these traits. This study provides the first evidence for the induction of Physical Defenses in prickly poppies, emphasizing how an ontogenetically explicit framework can reveal new insights into plant Defense. Moreover, this study illustrates how sister species comparisons between island vs. continental plants can provide new insights into plant functional and evolutionary ecology, highlighting a fruitful area for future research on more species pairs.
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the ontogeny of plant Defense and herbivory characterizing general patterns using meta analysis
The American Naturalist, 2010Co-Authors: Kasey E. Barton, Julia KorichevaAbstract:Abstract: Defense against herbivores often changes dramatically as plants develop. Hypotheses based on allocation theory and herbivore selection patterns predict that Defense should increase or decrease, respectively, across ontogeny, and previous research partly supports both predictions. Thus, it remains unclear which pattern is more common and what factors contribute to variability among studies. We conducted a meta‐analysis of 116 published studies reporting ontogenetic patterns in plant Defense traits and herbivory. Patterns varied depending on plant life form (woody, herbaceous, grass), type of herbivore (insect, mollusk, mammal), and type of Defense trait (secondary chemistry, Physical Defense, tolerance). In woody plants, chemical Defense increased during the seedling stage, followed by an increase in Physical Defenses during the vegetative juvenile stage. Mammalian herbivores showed a strong preference for mature compared to juvenile tissues in woody plants. Herbs experienced a significant increa...
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the ontogeny of plant Defense and herbivory characterizing general patterns using meta analysis
The American Naturalist, 2010Co-Authors: Kasey E. Barton, Julia KorichevaAbstract:Defense against herbivores often changes dramatically as plants develop. Hypotheses based on allocation theory and herbivore selection patterns predict that Defense should increase or decrease, respectively, across ontogeny, and previous research partly supports both predictions. Thus, it remains unclear which pattern is more common and what factors contribute to variability among studies. We conducted a meta-analysis of 116 published studies reporting ontogenetic patterns in plant Defense traits and herbivory. Patterns varied depending on plant life form (woody, herbaceous, grass), type of herbivore (insect, mollusk, mammal), and type of Defense trait (secondary chemistry, Physical Defense, tolerance). In woody plants, chemical Defense increased during the seedling stage, followed by an increase in Physical Defenses during the vegetative juvenile stage. Mammalian herbivores showed a strong preference for mature compared to juvenile tissues in woody plants. Herbs experienced a significant increase in secondary chemistry across the entire ontogenetic trajectory, although the magnitude of increase was greatest during the seedling stage. Correspondingly, mollusks preferred young compared to older herbs. Future research investigating growth/Defense trade-offs, allometry, herbivore selection patterns, and ecological costs would shed light on the mechanisms driving the ontogenetic patterns observed.
Juan Nunezfarfan - One of the best experts on this subject based on the ideXlab platform.
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selection mosaic exerted by specialist and generalist herbivores on chemical and Physical Defense of datura stramonium
PLOS ONE, 2014Co-Authors: Guillermo Castillo, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Rosalinda Tapialopez, Erika Olmedovicente, Diego Carmona, Ana Luisa Anayalang, Guadalupe Andracagomez, Juan NunezfarfanAbstract:Selection exerted by herbivores is a major force driving the evolution of plant defensive characters such as leaf trichomes or secondary metabolites. However, plant Defense expression is highly variable among populations and identifying the sources of this variation remains a major challenge. Plant populations are often distributed across broad geographic ranges and are exposed to different herbivore communities, ranging from generalists (that feed on diverse plant species) to specialists (that feed on a restricted group of plants). We studied eight populations of the plant Datura stramonium usually eaten by specialist or generalist herbivores, in order to examine whether the pattern of phenotypic selection on secondary compounds (atropine and scopolamine) and a Physical Defense (trichome density) can explain geographic variation in these traits. Following co-evolutionary theory, we evaluated whether a more derived alkaloid (scopolamine) confers higher fitness benefits than its precursor (atropine), and whether this effect differs between specialist and generalist herbivores. Our results showed consistent directional selection in almost all populations and herbivores to reduce the concentration of atropine. The most derived alkaloid (scopolamine) was favored in only one of the populations, which is dominated by a generalist herbivore. In general, the patterns of selection support the existence of a selection mosaic and accounts for the positive correlation observed between atropine concentration and plant damage by herbivores recorded in previous studies.
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geographic association and temporal variation of chemical and Physical Defense and leaf damage in datura stramonium
Ecological Research, 2013Co-Authors: Guillermo Castillo, Ken Oyama, Johnattan Hernandezcumplido, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Cesar M Floresortiz, Juan NunezfarfanAbstract:The evolution of plant Defense traits has traditionally been explained trough the “coevolutionary arms race” between plants and herbivores. According to this, specialist herbivores have evolved to cope effectively with the defensive traits of their host plants and may even use them as a cue for host location. We analyzed the geographic association between leaf trichomes, two tropane alkaloids (putative resistance traits), and leaf damage by herbivores in 28 populations of Datura stramonium in central Mexico. Since the specialist leaf beetles Epitrix parvula and Lema trilineata are the main herbivores of D. stramonium in central Mexico, we predicted a positive association between plant Defense and leaf damage across populations. Also, if Physical environmental conditions (temperature or precipitation) constrain the expression of plant Defense, then the geographic variation in leaf damage should be explained partially by the interaction between defensive traits and environmental factors. Furthermore, we studied the temporal and spatial variation in leaf trichome density and leaf damage in five selected populations of D. stramonium sampled in two periods (1997 vs. 2007). We found a positive association between leaf trichomes density and atropine concentration with leaf damage across populations. The interaction between defensive traits and water availability in each locality had a significant effect on the geographic variation in leaf damage. Differences among populations in leaf trichome density are maintained over time. Our results indicate that local plant–herbivore interaction plays an important role in shaping the geographic and temporal variation in plant Defense in D. stramonium.
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geographic association and temporal variation of chemical and Physical Defense and leaf damage in datura stramonium
Ecological Research, 2013Co-Authors: Guillermo Castillo, Ken Oyama, Johnattan Hernandezcumplido, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Cesar M Floresortiz, Juan NunezfarfanAbstract:The evolution of plant Defense traits has traditionally been explained trough the “coevolutionary arms race” between plants and herbivores. According to this, specialist herbivores have evolved to cope effectively with the defensive traits of their host plants and may even use them as a cue for host location. We analyzed the geographic association between leaf trichomes, two tropane alkaloids (putative resistance traits), and leaf damage by herbivores in 28 populations of Datura stramonium in central Mexico. Since the specialist leaf beetles Epitrix parvula and Lema trilineata are the main herbivores of D. stramonium in central Mexico, we predicted a positive association between plant Defense and leaf damage across populations. Also, if Physical environmental conditions (temperature or precipitation) constrain the expression of plant Defense, then the geographic variation in leaf damage should be explained partially by the interaction between defensive traits and environmental factors. Furthermore, we studied the temporal and spatial variation in leaf trichome density and leaf damage in five selected populations of D. stramonium sampled in two periods (1997 vs. 2007). We found a positive association between leaf trichomes density and atropine concentration with leaf damage across populations. The interaction between defensive traits and water availability in each locality had a significant effect on the geographic variation in leaf damage. Differences among populations in leaf trichome density are maintained over time. Our results indicate that local plant–herbivore interaction plays an important role in shaping the geographic and temporal variation in plant Defense in D. stramonium.
Julia Koricheva - One of the best experts on this subject based on the ideXlab platform.
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the ontogeny of plant Defense and herbivory characterizing general patterns using meta analysis
The American Naturalist, 2010Co-Authors: Kasey E. Barton, Julia KorichevaAbstract:Abstract: Defense against herbivores often changes dramatically as plants develop. Hypotheses based on allocation theory and herbivore selection patterns predict that Defense should increase or decrease, respectively, across ontogeny, and previous research partly supports both predictions. Thus, it remains unclear which pattern is more common and what factors contribute to variability among studies. We conducted a meta‐analysis of 116 published studies reporting ontogenetic patterns in plant Defense traits and herbivory. Patterns varied depending on plant life form (woody, herbaceous, grass), type of herbivore (insect, mollusk, mammal), and type of Defense trait (secondary chemistry, Physical Defense, tolerance). In woody plants, chemical Defense increased during the seedling stage, followed by an increase in Physical Defenses during the vegetative juvenile stage. Mammalian herbivores showed a strong preference for mature compared to juvenile tissues in woody plants. Herbs experienced a significant increa...
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the ontogeny of plant Defense and herbivory characterizing general patterns using meta analysis
The American Naturalist, 2010Co-Authors: Kasey E. Barton, Julia KorichevaAbstract:Defense against herbivores often changes dramatically as plants develop. Hypotheses based on allocation theory and herbivore selection patterns predict that Defense should increase or decrease, respectively, across ontogeny, and previous research partly supports both predictions. Thus, it remains unclear which pattern is more common and what factors contribute to variability among studies. We conducted a meta-analysis of 116 published studies reporting ontogenetic patterns in plant Defense traits and herbivory. Patterns varied depending on plant life form (woody, herbaceous, grass), type of herbivore (insect, mollusk, mammal), and type of Defense trait (secondary chemistry, Physical Defense, tolerance). In woody plants, chemical Defense increased during the seedling stage, followed by an increase in Physical Defenses during the vegetative juvenile stage. Mammalian herbivores showed a strong preference for mature compared to juvenile tissues in woody plants. Herbs experienced a significant increase in secondary chemistry across the entire ontogenetic trajectory, although the magnitude of increase was greatest during the seedling stage. Correspondingly, mollusks preferred young compared to older herbs. Future research investigating growth/Defense trade-offs, allometry, herbivore selection patterns, and ecological costs would shed light on the mechanisms driving the ontogenetic patterns observed.
Vered Tzin - One of the best experts on this subject based on the ideXlab platform.
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The Effectiveness of Physical and Chemical Defense Responses of Wild Emmer Wheat Against Aphids Depends on Leaf Position and Genotype
'Frontiers Media SA', 2021Co-Authors: Anuradha Singh, Brian Dilkes, Hanan Sela, Vered TzinAbstract:The bird cherry-oat aphid (Rhopalosiphum padi) is one of the most destructive insect pests in wheat production. To reduce aphid damage, wheat plants have evolved various chemical and Physical Defense mechanisms. Although these mechanisms have been frequently reported, much less is known about their effectiveness. The tetraploid wild emmer wheat (WEW; Triticum turgidum ssp. dicoccoides), one of the progenitors of domesticated wheat, possesses untapped resources from its numerous desirable traits, including insect resistance. The goal of this research was to determine the effectiveness of trichomes (Physical Defense) and benzoxazinoids (BXDs; chemical Defense) in aphid resistance by exploiting the natural diversity of WEW. We integrated a large dataset composed of trichome density and BXD abundance across wheat genotypes, different leaf positions, conditions (constitutive and aphid-induced), and tissues (whole leaf and phloem sap). First, we evaluated aphid reproduction on 203 wheat accessions and found large variation in this trait. Then, we chose eight WEW genotypes and one domesticated durum wheat cultivar for detailed quantification of the Defense mechanisms across three leaves. We discovered that these Defense mechanisms are influenced by both leaf position and genotype, where aphid reproduction was the highest on leaf-1 (the oldest), and trichome density was the lowest. We compared the changes in trichome density and BXD levels upon aphid infestation and found only minor changes relative to untreated plants. This suggests that the Defense mechanisms in the whole leaf are primarily anticipatory and unlikely to contribute to aphid-induced Defense. Next, we quantified BXD levels in the phloem sap and detected a significant induction of two compounds upon aphid infestation. Moreover, evaluating aphid feeding patterns showed that aphids prefer to feed on the oldest leaf. These findings revealed the dynamic response at the whole leaf and phloem levels that altered aphid feeding and reproduction. Overall, they suggested that trichomes and the BXD 2,4-dihydroxy-7- methoxy-1,4-benzoxazin-3-one (DIMBOA) levels are the main factors determining aphid resistance, while trichomes are more effective than BXDs. Accessions from the WEW germplasm, rich with trichomes and BXDs, can be used as new genetic sources to improve the resistance of elite wheat cultivars
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variation between three eragrostis tef accessions in Defense responses to rhopalosiphum padi aphid infestation
Frontiers in Plant Science, 2020Co-Authors: Nathan M Gyan, Beery Yaakov, Anuradha Singh, Nati Weinblum, Alon Cnaani, Shiran Benzeev, Yehoshua Saranga, Vered TzinAbstract:Tef (Eragrostis tef), a staple crop that originated in the Horn of Africa, has been introduced to multiple countries over the last several decades. Crop cultivation in new geographic regions raises questions regarding the molecular basis for biotic stress responses. In this study, we aimed to classify the insect abundance on tef crop in Israel, and to elucidate its chemical and Physical Defense mechanisms in response to insect feeding. To discover the main pests of tef in the Mediterranean climate, we conducted an insect field survey on three selected accessions named RTC-144, RTC-405, and RTC-406, and discovered that the most abundant insect order is Hemiptera. We compared the differences in Rhopalosiphum padi (Hemiptera; Aphididae) aphid performance, preference, and feeding behavior between the three accessions. While the number of aphid progeny was lower on RTC-406 than on the other two, the aphid olfactory assay indicated that the aphids tended to be repelled from the RTC-144 accession. To highlight the variation in Defense responses, we investigated the Physical and chemical mechanisms. As a Physical barrier, the density of non-granular trichomes was evaluated, in which a higher number of trichomes on the RTC-406 than on the other accessions was observed. This was negatively correlated with aphid performance. To determine chemical responses, the volatile and central metabolite profiles were measured upon aphid attack for 4 days. The volatile analysis exposed a rich and dynamic metabolic profile, and the central metabolism profile indicated that tef plants adjust their sugars and organic and amino acid levels. Overall, we found that the tef plants possess similar Defense responses as other Poaceae family species, while the non-volatile deterrent compounds are yet to be characterized. A transcriptomic time-series analysis of a selected accession RTC-144 infested with aphids revealed a massive alteration of genes related to specialized metabolism that potentially synthesize non-volatile toxic compounds. This is the first report to reveal the variation in the Defense mechanisms of tef plants. These findings can facilitate the discovery of insect-resistance genes leading to enhanced yield in tef and other cereal crops.
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comparative transcriptomic and metabolic analysis of wild and domesticated wheat genotypes reveals differences in chemical and Physical Defense responses against aphids
BMC Plant Biology, 2020Co-Authors: Zhaniya S Batyrshina, Beery Yaakov, Reut Shavit, Anuradha Singh, Vered TzinAbstract:Young wheat plants are continuously exposed to herbivorous insect attack. To reduce insect damage and maintain their growth, plants evolved different Defense mechanisms, including the biosynthesis of deterrent compounds named benzoxazinoids, and/or trichome formation that provides Physical barriers. It is unclear whether both of these mechanisms are equally critical in providing an efficient Defense for wheat seedlings against aphids—an economically costly pest in cereal production. In this study, we compared the transcriptome, metabolome, benzoxazinoids, and trichome density of three selected wheat genotypes, with a focus on differences related to Defense mechanisms. We chose diverse wheat genotypes: two tetraploid wheat genotypes, domesticated durum ‘Svevo’ and wild emmer ‘Zavitan,’ and one hexaploid bread wheat, ‘Chinese Spring.’ The full transcriptomic analysis revealed a major difference between the three genotypes, while the clustering of significantly different genes suggested a higher similarity between the two domesticated wheats than between either and the wild wheat. A pathway enrichment analysis indicated that the genes associated with primary metabolism, as well as the pathways associated with Defense such as phytohormones and specialized metabolites, were different between the three genotypes. Measurement of benzoxazinoid levels at the three time points (11, 15, and 18 days after germination) revealed high levels in the two domesticated genotypes, while in wild emmer wheat, they were below detection level. In contrast to the benzoxazinoid levels, the trichome density was dramatically higher in the wild emmer than in the domesticated wheat. Lastly, we tested the bird cherry-oat aphid’s (Rhopalosiphum padi) performance and found that Chinese Spring is more resistant than the tetraploid genotypes. Our results show that benzoxazinoids play a more significant defensive role than trichomes. Differences between the abundance of Defense mechanisms in the wild and domesticated plants were observed in which wild emmer possesses high Physical Defenses while the domesticated wheat genotypes have high chemical Defenses. These findings provide new insights into the Defense adaptations of wheat plants against aphids.
Guillermo Castillo - One of the best experts on this subject based on the ideXlab platform.
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selection mosaic exerted by specialist and generalist herbivores on chemical and Physical Defense of datura stramonium
PLOS ONE, 2014Co-Authors: Guillermo Castillo, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Rosalinda Tapialopez, Erika Olmedovicente, Diego Carmona, Ana Luisa Anayalang, Guadalupe Andracagomez, Juan NunezfarfanAbstract:Selection exerted by herbivores is a major force driving the evolution of plant defensive characters such as leaf trichomes or secondary metabolites. However, plant Defense expression is highly variable among populations and identifying the sources of this variation remains a major challenge. Plant populations are often distributed across broad geographic ranges and are exposed to different herbivore communities, ranging from generalists (that feed on diverse plant species) to specialists (that feed on a restricted group of plants). We studied eight populations of the plant Datura stramonium usually eaten by specialist or generalist herbivores, in order to examine whether the pattern of phenotypic selection on secondary compounds (atropine and scopolamine) and a Physical Defense (trichome density) can explain geographic variation in these traits. Following co-evolutionary theory, we evaluated whether a more derived alkaloid (scopolamine) confers higher fitness benefits than its precursor (atropine), and whether this effect differs between specialist and generalist herbivores. Our results showed consistent directional selection in almost all populations and herbivores to reduce the concentration of atropine. The most derived alkaloid (scopolamine) was favored in only one of the populations, which is dominated by a generalist herbivore. In general, the patterns of selection support the existence of a selection mosaic and accounts for the positive correlation observed between atropine concentration and plant damage by herbivores recorded in previous studies.
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geographic association and temporal variation of chemical and Physical Defense and leaf damage in datura stramonium
Ecological Research, 2013Co-Authors: Guillermo Castillo, Ken Oyama, Johnattan Hernandezcumplido, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Cesar M Floresortiz, Juan NunezfarfanAbstract:The evolution of plant Defense traits has traditionally been explained trough the “coevolutionary arms race” between plants and herbivores. According to this, specialist herbivores have evolved to cope effectively with the defensive traits of their host plants and may even use them as a cue for host location. We analyzed the geographic association between leaf trichomes, two tropane alkaloids (putative resistance traits), and leaf damage by herbivores in 28 populations of Datura stramonium in central Mexico. Since the specialist leaf beetles Epitrix parvula and Lema trilineata are the main herbivores of D. stramonium in central Mexico, we predicted a positive association between plant Defense and leaf damage across populations. Also, if Physical environmental conditions (temperature or precipitation) constrain the expression of plant Defense, then the geographic variation in leaf damage should be explained partially by the interaction between defensive traits and environmental factors. Furthermore, we studied the temporal and spatial variation in leaf trichome density and leaf damage in five selected populations of D. stramonium sampled in two periods (1997 vs. 2007). We found a positive association between leaf trichomes density and atropine concentration with leaf damage across populations. The interaction between defensive traits and water availability in each locality had a significant effect on the geographic variation in leaf damage. Differences among populations in leaf trichome density are maintained over time. Our results indicate that local plant–herbivore interaction plays an important role in shaping the geographic and temporal variation in plant Defense in D. stramonium.
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geographic association and temporal variation of chemical and Physical Defense and leaf damage in datura stramonium
Ecological Research, 2013Co-Authors: Guillermo Castillo, Ken Oyama, Johnattan Hernandezcumplido, Pedro Luis Valverde, Laura L Cruz, Juan Fornoni, Cesar M Floresortiz, Juan NunezfarfanAbstract:The evolution of plant Defense traits has traditionally been explained trough the “coevolutionary arms race” between plants and herbivores. According to this, specialist herbivores have evolved to cope effectively with the defensive traits of their host plants and may even use them as a cue for host location. We analyzed the geographic association between leaf trichomes, two tropane alkaloids (putative resistance traits), and leaf damage by herbivores in 28 populations of Datura stramonium in central Mexico. Since the specialist leaf beetles Epitrix parvula and Lema trilineata are the main herbivores of D. stramonium in central Mexico, we predicted a positive association between plant Defense and leaf damage across populations. Also, if Physical environmental conditions (temperature or precipitation) constrain the expression of plant Defense, then the geographic variation in leaf damage should be explained partially by the interaction between defensive traits and environmental factors. Furthermore, we studied the temporal and spatial variation in leaf trichome density and leaf damage in five selected populations of D. stramonium sampled in two periods (1997 vs. 2007). We found a positive association between leaf trichomes density and atropine concentration with leaf damage across populations. The interaction between defensive traits and water availability in each locality had a significant effect on the geographic variation in leaf damage. Differences among populations in leaf trichome density are maintained over time. Our results indicate that local plant–herbivore interaction plays an important role in shaping the geographic and temporal variation in plant Defense in D. stramonium.