The Experts below are selected from a list of 3282 Experts worldwide ranked by ideXlab platform
Jacobus C De Roode - One of the best experts on this subject based on the ideXlab platform.
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transcriptomics of monarch butterflies danaus plexippus reveals that toxic host plants alter expression of detoxification genes and down regulate a small number of immune genes
Molecular Ecology, 2019Co-Authors: Wenhao Tan, James R. Walters, Mark D Hunter, Tarik Acevedo, Erica V Harris, Tiffanie Y Alcaide, Nicole M Gerardo, Jacobus C De RoodeAbstract:Herbivorous insects have evolved many mechanisms to overcome plant chemical defences, including detoxification and sequestration. Herbivores may also use toxic plants to reduce parasite infection. Plant toxins could directly interfere with parasites or could enhance endogenous immunity. Alternatively, plant toxins could favour down-regulation of endogenous immunity by providing an alternative (exogenous) defence against parasitism. However, studies on genomewide transcriptomic responses to plant defences and the interplay between plant toxicity and parasite infection remain rare. Monarch butterflies (Danaus plexippus) are specialist herbivores of Milkweeds (Asclepias spp.), which contain toxic cardenolides. Monarchs have adapted to cardenolides through multiple resistance mechanisms and can sequester cardenolides to defend against bird predators. In addition, high-cardenolide Milkweeds confer monarch resistance to a specialist protozoan parasite (Ophryocystis elektroscirrha). We used this system to study the interplay between the effects of plant toxicity and parasite infection on global gene expression. We compared transcriptional profiles between parasite-infected and uninfected monarch larvae reared on two Milkweed species. Our results demonstrate that monarch differentially express several hundred genes when feeding on A. curassavica and A. incarnata, two species that differ substantially in cardenolide concentrations. These differentially expressed genes include genes within multiple families of canonical insect detoxification genes, suggesting that they play a role in monarch toxin resistance and sequestration. Interestingly, we found little transcriptional response to infection. However, parasite growth was reduced in monarchs reared on A. curassavica, and in these monarchs, several immune genes were down-regulated, consistent with the hypothesis that medicinal plants can reduce reliance on endogenous immunity.
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the effects of Milkweed induced defense on parasite resistance in monarch butterflies danaus plexippus
Journal of Chemical Ecology, 2018Co-Authors: Wenhao Tan, Mark D Hunter, Leiling Tao, Kevin M Hoang, Jacobus C De RoodeAbstract:Many plants express induced defenses against herbivores through increasing the production of toxic secondary chemicals following damage. Phytochemical induction can directly or indirectly affect other organisms within the community. In tri-trophic systems, increased concentrations of plant toxins could be detrimental to plants if herbivores can sequester these toxins as protective chemicals for themselves. Thus, through trophic interactions, induction can lead to either positive or negative effects on plant fitness. We examined the effects of Milkweed (Asclepias spp.) induced defenses on the resistance of monarch caterpillars (Danaus plexippus) to a protozoan parasite (Ophryocystis elektroscirrha). Milkweeds contain toxic secondary chemicals called cardenolides, higher concentrations of which are associated with reduced parasite growth. Previous work showed that declines in foliar cardenolides caused by aphid attack render monarch caterpillars more susceptible to infection. Here, we ask whether cardenolide induction by monarchs increases monarch resistance to disease. We subjected the high-cardenolide Milkweed A. curassavica and the low-cardenolide A. syriaca to caterpillar grazing, and reared infected and uninfected caterpillars on these plants. As expected, monarchs suffered less parasite growth and disease when reared on A. curassavica than on A. syriaca. We also found that herbivory increased cardenolide concentrations in A. curassavica, but not A. syriaca. However, cardenolide induction in A. curassavica was insufficient to influence monarch resistance to the parasite. Our results suggest that interspecific variation in cardenolide concentration is a more important driver of parasite defense than plasticity via induced defenses in this tri-trophic system.
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disease ecology across soil boundaries effects of below ground fungi on above ground host parasite interactions
Proceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Camden D. Gowler, Mark D Hunter, Aamina Ahmad, Jacobus C De RoodeAbstract:Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (Milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of Milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in Milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems.
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Secondary Defense Chemicals in Milkweed Reduce Parasite Infection in Monarch Butterflies, Danaus plexippus
Journal of Chemical Ecology, 2015Co-Authors: Camden D. Gowler, Mark D Hunter, Kristoffer E. Leon, Jacobus C De RoodeAbstract:In tri-trophic systems, herbivores may benefit from their host plants in fighting parasitic infections. Plants can provide parasite resistance in two contrasting ways: either directly, by interfering with the parasite, or indirectly, by increasing herbivore immunity or health. In monarch butterflies, the larval diet of Milkweed strongly influences the fitness of a common protozoan parasite. Toxic secondary plant chemicals known as cardenolides correlate strongly with parasite resistance of the host, with greater cardenolide concentrations in the larval diet leading to lower parasite growth. However, Milkweed cardenolides may covary with other indices of plant quality including nutrients, and a direct experimental link between cardenolides and parasite performance has not been established. To determine if the anti-parasitic activity of Milkweeds is indeed due to secondary chemicals, as opposed to nutrition, we supplemented the diet of infected and uninfected monarch larvae with Milkweed latex, which contains cardenolides but no nutrients. Across three experiments, increased dietary cardenolide concentrations reduced parasite growth in infected monarchs, which consequently had longer lifespans. However, uninfected monarchs showed no differences in lifespan across treatments, confirming that cardenolide-containing latex does not increase general health. Our results suggest that cardenolides are a driving force behind plant-derived resistance in this system.
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food plant derived disease tolerance and resistance in a natural butterfly plant parasite interactions
Evolution, 2012Co-Authors: Eleanore D Sternberg, Mark D Hunter, Thierry Lefevre, Carlos Lopez Fernandez De Castillejo, Jacobus C De RoodeAbstract:Organisms can protect themselves against parasite-induced fitness costs through resistance or tolerance. Resistance includes mechanisms that prevent infection or limit parasite growth while tolerance alleviates the fitness costs from parasitism without limiting infection. Although tolerance and resistance affect host-parasite coevolution in fundamentally different ways, tolerance has often been ignored in animal-parasite systems. Where it has been studied, tolerance has been assumed to be a genetic mechanism, unaffected by the host environment. Here we studied the effects of host ecology on tolerance and resistance to infection by rearing monarch butterflies on 12 different species of Milkweed food plants and infecting them with a naturally occurring protozoan parasite. Our results show that monarch butterflies experience different levels of tolerance to parasitism depending on the species of Milkweed that they feed on, with some species providing over twofold greater tolerance than other Milkweed species. Resistance was also affected by Milkweed species, but there was no relationship between Milkweed-conferred resistance and tolerance. Chemical analysis suggests that infected monarchs obtain highest fitness when reared on Milkweeds with an intermediate concentration, diversity, and polarity of toxic secondary plant chemicals known as cardenolides. Our results demonstrate that environmental factors-such as interacting species in ecological food webs-are important drivers of disease tolerance.
Stephen B Malcolm - One of the best experts on this subject based on the ideXlab platform.
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suitability of native Milkweed asclepias species versus cultivars for supporting monarch butterflies and bees in urban gardens
PeerJ, 2020Co-Authors: Adam M. Baker, Stephen B Malcolm, Carl T Redmond, Daniel A. PotterAbstract:Public interest in ecological landscaping and gardening is fueling a robust market for native plants. Most plants available to consumers through the horticulture trade are cultivated forms that have been selected for modified flowers or foliage, compactness, or other ornamental characteristics. Depending on their traits, some native plant cultivars seem to support pollinators, specialist insect folivores, and insect-based vertebrate food webs as effectively as native plant species, whereas others do not. There is particular need for information on whether native cultivars can be as effective as true or "wild-type" native species for supporting specialist native insects of conservation concern. Herein we compared the suitability of native Milkweed species and their cultivars for attracting and supporting one such insect, the iconic monarch butterfly (Danaus plexippus L.), as well as native bees in urban pollinator gardens. Wild-type Asclepias incarnata L. (swamp Milkweed) and Asclepias tuberosa L. (butterfly Milkweed) and three additional cultivars of each that vary in stature, floral display, and foliage color were grown in a replicated common garden experiment at a public arboretum. We monitored the plants for colonization by wild monarchs, assessed their suitability for supporting monarch larvae in greenhouse trials, measured their defensive characteristics (leaf trichome density, latex, and cardenolide levels), and compared the proportionate abundance and diversity of bee families and genera visiting their blooms. Significantly more monarch eggs and larvae were found on A. incarnata than A. tuberosa in both years, but within each Milkweed group, cultivars were colonized to the same extent as wild types. Despite some differences in defense allocation, all cultivars were as suitable as wild-type Milkweeds in supporting monarch larval growth. Five bee families and 17 genera were represented amongst the 2,436 total bees sampled from blooms of wild-type Milkweeds and their cultivars in the replicated gardens. Bee assemblages of A. incarnata were dominated by Apidae (Bombus, Xylocopa spp., and Apis mellifera), whereas A. tuberosa attracted relatively more Halictidae (especially Lasioglossum spp.) and Megachilidae. Proportionate abundance of bee families and genera was generally similar for cultivars and their respective wild types. This study suggests that, at least in small urban gardens, Milkweed cultivars can be as suitable as their parental species for supporting monarch butterflies and native bees.
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First-instar monarch larval growth and survival on Milkweeds in southern California: effects of latex, leaf hairs and cardenolides
Chemoecology, 2012Co-Authors: Myron P Zalucki, Stephen B Malcolm, Christopher C. Hanlon, Timothy D. PaineAbstract:Growth rate and survival of first-instar larvae of Danaus plexippus , a Milkweed specialist, depended on Milkweed species, and was related to the amount of latex produced from wounds, leaf cardenolide concentrations and the presence of leaf hairs. Larval growth was more rapid and survival was higher on leaves of Asclepias californica with experimentally reduced latex, and this species has characteristically high latex, low- to mid-range cardenolide concentrations, and very hirsute leaves. Similarly, growth was higher on reduced latex leaves of both A. eriocarpa (a high latex/high cardenolide, hirsute species) and A. erosa (glabrous fleshy leaves, high latex/high cardenolides). There were no differences in either survival or growth rate between larvae on reduced latex or control leaves of the low latex/low cardenolide A. fascicularis with soft glabrous leaves and both survival and growth rate were higher on this species than the other species tested. Larval growth rates on leaves with reduced latex were similar among ten Milkweed species tested to date but differed from growth rates on intact leaves suggesting that latex and possibly included cardenolides are both important in first-instar monarch larval growth, development and survival. We show for a range of ecologically important Milkweeds that experiments on cut plant material (no latex outflow) lead to higher growth rates compared to intact plants. Such laboratory assays based on detached leaves will be misleading if the objective is to determine the impact of treatments such as Bt -maize pollen on monarchs on field plants.
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it s the first bites that count survival of first instar monarchs on Milkweeds
Austral Ecology, 2001Co-Authors: Myron P Zalucki, Stephen B Malcolm, Lincoln P Brower, Christopher C. Hanlon, Timothy D. Paine, Anthony R ClarkeAbstract:Mortality of first instars is generally very high, but variable, and is caused by many factors, including physical and chemical plant characters, weather and natural enemies. Here, a summary of detailed field-based studies of the early-stage survival of a specialist lepidopteran herbivore is presented. First-instar larvae of the monarch butterfly, Danaus plexippus, a Milkweed specialist, generally grew faster and survived better on leaves when latex flow was reduced by partial severance of the leaf petiole. The outcome depended on Milkweed species, and was related to the amount of latex produced, as well as other plant characters, such as leaf hairs, microclimate and concentration of secondary metabolites. Even for a so-called 'Milkweed specialist', larval performance and survival appears to be related to the concentration of cardenolides produced by the plants (a potential chemical defence against herbivory). This case study of monarchs and Milkweeds highlights the need for field-based experiments to assess the effect of plant characters on the usually poor survival of early instar phytophagous insects. Few similar studies concerning the performance and survival of first-instar, eucalypt-specific herbivores have been conducted, but this type of study is considered essential based on the findings obtained using D. plexippus.
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specialist weevil rhyssomatus lineaticollis does not spatially avoid cardenolide defenses of common Milkweed by ovipositing into pith tissue
Journal of Chemical Ecology, 2000Co-Authors: James A Fordyce, Stephen B MalcolmAbstract:Rhyssomatus lineaticollis is a Milkweed specialist whose larvae feed upon pith parenchyma in ramet stems of the common Milkweed, Asclepias syriaca. Compared with other specialist insect herbivores on Milkweeds, this curculionid beetle is unusual in that it is cryptically colored and does not sequester cardenolides characteristic of Milkweed chemical defense. Based upon optimal defense theory, we predicted that pith tissue would be low in defensive compounds and that oviposition into the pith would spatially avoid cardenolides. We rejected this hypothesis because we found that pith tissue has a relatively high cardenolide concentration compared to cortex, epidermis, and leaf tissues. Moreover, we found total plant cardenolide concentration was lower in plants that contained the beetle eggs. Cardenolide concentrations were different among tissues in intact stems without the pith herbivore compared to stems where it was present. Furthermore, the overall polarity of the cardenolides present varied among plant tissues and between plants with and without R. lineaticollis eggs. Although we found lower concentrations of cardenolide in piths where the eggs were present, the cardenolides present in the pith contained more nonpolar forms, indicating that the plant may be responding to herbivory by increasing toxic efficacy of cardenolide defenses while lowering the total concentration. We suggest that preoviposition behavior by female beetles, which includes feeding on new leaves of the plant, is a mechanism by which females manipulate plant chemistry and assess quantitative and qualitative changes in cardenolide chemistry in response to herbivory prior to oviposition.
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Milkweeds, monarch butterflies and the ecological significance of cardenolides
CHEMOECOLOGY, 1994Co-Authors: Stephen B MalcolmAbstract:The contribution of Miriam Rothschild to the “monarch cardenolide story” is reviewed in the light of the 1914 challenge by the evolutionary biologist, E.B. Poulton for North American chemists to explain the chemical basis of unpalatability in monarch butterflies and their Milkweed host plants. This challenge had lain unaccepted for nearly 50 years until Miriam Rothschild took up the gauntlet and showed with the help of many able colleagues that monarchs are aposematically coloured because they sequester toxic cardenolides from Milkweed host plants for use as a defence against predators. By virtue of Dr Rothschild's inspiration and industry, and subsequently that of Lincoln Brower and his colleagues, this tritrophic interaction has become a familiar paradigm for the evolution of chemical defences and warning colouration. We now know that the cardenolide contents of different Milkweeds vary quantitatively, qualitatively and spatially, both within and among species and we are starting to appreciate the implications of such variation. However, as Dr Rothschild has pointed out in her publications, cardenolides have sometimes blinded us to reality and it is curious how little evidence there is for a defensive function to cardenolides in plants — especially against adapted specialists such as the monarch. Thus the review will conclude with a discussion of the significance of temporal variation and induction of cardenolide production in plants, the “lethal plant defence paradox” and an emphasis on the dynamics of the cardenolide-mediated interaction between Milkweeds and monarch larvae.
Mark D Hunter - One of the best experts on this subject based on the ideXlab platform.
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transcriptomics of monarch butterflies danaus plexippus reveals that toxic host plants alter expression of detoxification genes and down regulate a small number of immune genes
Molecular Ecology, 2019Co-Authors: Wenhao Tan, James R. Walters, Mark D Hunter, Tarik Acevedo, Erica V Harris, Tiffanie Y Alcaide, Nicole M Gerardo, Jacobus C De RoodeAbstract:Herbivorous insects have evolved many mechanisms to overcome plant chemical defences, including detoxification and sequestration. Herbivores may also use toxic plants to reduce parasite infection. Plant toxins could directly interfere with parasites or could enhance endogenous immunity. Alternatively, plant toxins could favour down-regulation of endogenous immunity by providing an alternative (exogenous) defence against parasitism. However, studies on genomewide transcriptomic responses to plant defences and the interplay between plant toxicity and parasite infection remain rare. Monarch butterflies (Danaus plexippus) are specialist herbivores of Milkweeds (Asclepias spp.), which contain toxic cardenolides. Monarchs have adapted to cardenolides through multiple resistance mechanisms and can sequester cardenolides to defend against bird predators. In addition, high-cardenolide Milkweeds confer monarch resistance to a specialist protozoan parasite (Ophryocystis elektroscirrha). We used this system to study the interplay between the effects of plant toxicity and parasite infection on global gene expression. We compared transcriptional profiles between parasite-infected and uninfected monarch larvae reared on two Milkweed species. Our results demonstrate that monarch differentially express several hundred genes when feeding on A. curassavica and A. incarnata, two species that differ substantially in cardenolide concentrations. These differentially expressed genes include genes within multiple families of canonical insect detoxification genes, suggesting that they play a role in monarch toxin resistance and sequestration. Interestingly, we found little transcriptional response to infection. However, parasite growth was reduced in monarchs reared on A. curassavica, and in these monarchs, several immune genes were down-regulated, consistent with the hypothesis that medicinal plants can reduce reliance on endogenous immunity.
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the effects of Milkweed induced defense on parasite resistance in monarch butterflies danaus plexippus
Journal of Chemical Ecology, 2018Co-Authors: Wenhao Tan, Mark D Hunter, Leiling Tao, Kevin M Hoang, Jacobus C De RoodeAbstract:Many plants express induced defenses against herbivores through increasing the production of toxic secondary chemicals following damage. Phytochemical induction can directly or indirectly affect other organisms within the community. In tri-trophic systems, increased concentrations of plant toxins could be detrimental to plants if herbivores can sequester these toxins as protective chemicals for themselves. Thus, through trophic interactions, induction can lead to either positive or negative effects on plant fitness. We examined the effects of Milkweed (Asclepias spp.) induced defenses on the resistance of monarch caterpillars (Danaus plexippus) to a protozoan parasite (Ophryocystis elektroscirrha). Milkweeds contain toxic secondary chemicals called cardenolides, higher concentrations of which are associated with reduced parasite growth. Previous work showed that declines in foliar cardenolides caused by aphid attack render monarch caterpillars more susceptible to infection. Here, we ask whether cardenolide induction by monarchs increases monarch resistance to disease. We subjected the high-cardenolide Milkweed A. curassavica and the low-cardenolide A. syriaca to caterpillar grazing, and reared infected and uninfected caterpillars on these plants. As expected, monarchs suffered less parasite growth and disease when reared on A. curassavica than on A. syriaca. We also found that herbivory increased cardenolide concentrations in A. curassavica, but not A. syriaca. However, cardenolide induction in A. curassavica was insufficient to influence monarch resistance to the parasite. Our results suggest that interspecific variation in cardenolide concentration is a more important driver of parasite defense than plasticity via induced defenses in this tri-trophic system.
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disease ecology across soil boundaries effects of below ground fungi on above ground host parasite interactions
Proceedings of The Royal Society B: Biological Sciences, 2015Co-Authors: Camden D. Gowler, Mark D Hunter, Aamina Ahmad, Jacobus C De RoodeAbstract:Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (Milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of Milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in Milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems.
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Secondary Defense Chemicals in Milkweed Reduce Parasite Infection in Monarch Butterflies, Danaus plexippus
Journal of Chemical Ecology, 2015Co-Authors: Camden D. Gowler, Mark D Hunter, Kristoffer E. Leon, Jacobus C De RoodeAbstract:In tri-trophic systems, herbivores may benefit from their host plants in fighting parasitic infections. Plants can provide parasite resistance in two contrasting ways: either directly, by interfering with the parasite, or indirectly, by increasing herbivore immunity or health. In monarch butterflies, the larval diet of Milkweed strongly influences the fitness of a common protozoan parasite. Toxic secondary plant chemicals known as cardenolides correlate strongly with parasite resistance of the host, with greater cardenolide concentrations in the larval diet leading to lower parasite growth. However, Milkweed cardenolides may covary with other indices of plant quality including nutrients, and a direct experimental link between cardenolides and parasite performance has not been established. To determine if the anti-parasitic activity of Milkweeds is indeed due to secondary chemicals, as opposed to nutrition, we supplemented the diet of infected and uninfected monarch larvae with Milkweed latex, which contains cardenolides but no nutrients. Across three experiments, increased dietary cardenolide concentrations reduced parasite growth in infected monarchs, which consequently had longer lifespans. However, uninfected monarchs showed no differences in lifespan across treatments, confirming that cardenolide-containing latex does not increase general health. Our results suggest that cardenolides are a driving force behind plant-derived resistance in this system.
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food plant derived disease tolerance and resistance in a natural butterfly plant parasite interactions
Evolution, 2012Co-Authors: Eleanore D Sternberg, Mark D Hunter, Thierry Lefevre, Carlos Lopez Fernandez De Castillejo, Jacobus C De RoodeAbstract:Organisms can protect themselves against parasite-induced fitness costs through resistance or tolerance. Resistance includes mechanisms that prevent infection or limit parasite growth while tolerance alleviates the fitness costs from parasitism without limiting infection. Although tolerance and resistance affect host-parasite coevolution in fundamentally different ways, tolerance has often been ignored in animal-parasite systems. Where it has been studied, tolerance has been assumed to be a genetic mechanism, unaffected by the host environment. Here we studied the effects of host ecology on tolerance and resistance to infection by rearing monarch butterflies on 12 different species of Milkweed food plants and infecting them with a naturally occurring protozoan parasite. Our results show that monarch butterflies experience different levels of tolerance to parasitism depending on the species of Milkweed that they feed on, with some species providing over twofold greater tolerance than other Milkweed species. Resistance was also affected by Milkweed species, but there was no relationship between Milkweed-conferred resistance and tolerance. Chemical analysis suggests that infected monarchs obtain highest fitness when reared on Milkweeds with an intermediate concentration, diversity, and polarity of toxic secondary plant chemicals known as cardenolides. Our results demonstrate that environmental factors-such as interacting species in ecological food webs-are important drivers of disease tolerance.
Perkins Dusty - One of the best experts on this subject based on the ideXlab platform.
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Do Showy Milkweed (\u3cem\u3eAsclepias speciosa\u3c/em\u3e) Leaf Characteristics Respond to Environmental Conditions?
'IUScholarWorks', 2020Co-Authors: Archey, Emma K., Cinello-smith Mia, Robinson Casey, Weedop Daison, Sonnen Michaela, Blackburn Leslie, Kilkenny Francis, Szymczycha Zackery, Perkins DustyAbstract:Monarch butterfly populations have declined since the 1970s due to habitat loss and fragmentation caused by human activities. Monarch conservation efforts call for the obligate host plants, Milkweeds, to be replenished across the Western US. By quantifying phenological and morphological variations of Showy Milkweed across the Intermountain West, our study will delineate seed transfer zones to maximize restorations success. Successful habitat restoration will require germplasm that is adapted for target restoration environments and seasonal phenology. We recorded leaf length, width, surface area, specific leaf area, and trichome densities from ten individuals among 35 populations raised in a common garden to inform photosynthetic capabilities, water use-efficiency, and defense against herbivory. By modeling relationships among leaf characteristics, climate and known herbivore responses, we can restore Milkweed that is both best adapted to the environment, and best suited to host Monarch larvae. As existing monarch butterfly populations represent less than 1% of historic abundance, effective conservation is needed to restore numbers to sustainable levels. Here we present our methodological approach for assessing leaf characters, and evaluate the implications that leaf traits have for both plant fitness and host plant suitability for monarch butterflies
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Phenological Variation Among Western Populations of Showy Milkweed (\u3cem\u3eAsclepias speciosa\u3c/em\u3e)
'IUScholarWorks', 2019Co-Authors: Cinello-smith Mia, Robinson Casey, Szymczycha, Zackery T., Weedop Daison, Sonnen Michaela, Blackburn Leslie, Kilkenny Francis, Perkins DustyAbstract:Western monarch butterflies (Danaus plexippus) have declined ~97% from historic abundances in the early 1980s and are being evaluated for listing under the Endangered Species Act. Habitat loss and fragmentation in wintering, migratory, and breeding areas are considered key causes. Since monarchs depend on Milkweeds (Asclepias sp.) for reproduction, there is increased interest among conservationists to plant Milkweeds as habitat restoration. Showy Milkweed (Aslceipias speciosa) is the most common and abundant Milkweed species in the Western US. Successful habitat restoration will require germplasm that is adapted for target restoration environments and seasonal phenology. Phenological traits are adaptive, easily observable, and shaped by climate; making them helpful in genecological applications for determining seed transfer zones. We evaluated phenological variation among 35 showy Milkweed populations from across the Intermountain West to determine geographic patterns of adaptive traits and their relationships to local climates using a common garden approach. We used remotely sensed climate data in conjunction with growth and reproductive phenology data to identify variation in adaptive traits and correlate them to elevation and climate variation. Here we present the results of our analyses and their implications for defining seed transfer zones for showy Milkweed in the context of monarch butterfly conservation
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Variation in Adaptive Traits and Seed Zone Evaluation of Showy Milkweed (\u3cem\u3eAsclepias speciosa\u3c/em\u3e)
'IUScholarWorks', 2019Co-Authors: Robinson Casey, Cinello-smith Mia, Szymczycha, Zackery T., Weedop Daison, Sonnen Michaela, Blackburn Leslie, Kilkenny Francis, Perkins DustyAbstract:Monarch butterfly (Danuas plexippus) populations are imperiled and in review for listing under the Endangered Species Act. Among many contributors to the decline is the loss of breeding, migratory, and overwintering habitat. Showy Milkweed (Asclepias speciosa) and other obligate Milkweeds are essential for monarch reproduction and have thus been cornerstones of monarch habitat restoration efforts in the Intermountain West. However, many potential restoration areas lack convenient seed sources to supply prospective efforts. Furthermore, because certain populations may be better adapted to specific local climates and selective pressures, the introduction of non-native, poorly adaptive genotypes may have negative consequences for restoration efforts and Milkweed-dependent species. We used a genecological approach to identify adaptive traits among 35 showy Milkweed populations from the Intermountain West to inform seed transfer zones for A. speciosa. We used morphological measures and plant growth data in conjunction with remotely sensed climate data to identify putative adaptive traits and determine how they relate to local climate variation. Here we present the results of our analyses and their implications for classifying showy Milkweed seed transfer zones and maximizing restoration and conservation benefit for monarch butterflies
Daniel A. Potter - One of the best experts on this subject based on the ideXlab platform.
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suitability of native Milkweed asclepias species versus cultivars for supporting monarch butterflies and bees in urban gardens
PeerJ, 2020Co-Authors: Adam M. Baker, Stephen B Malcolm, Carl T Redmond, Daniel A. PotterAbstract:Public interest in ecological landscaping and gardening is fueling a robust market for native plants. Most plants available to consumers through the horticulture trade are cultivated forms that have been selected for modified flowers or foliage, compactness, or other ornamental characteristics. Depending on their traits, some native plant cultivars seem to support pollinators, specialist insect folivores, and insect-based vertebrate food webs as effectively as native plant species, whereas others do not. There is particular need for information on whether native cultivars can be as effective as true or "wild-type" native species for supporting specialist native insects of conservation concern. Herein we compared the suitability of native Milkweed species and their cultivars for attracting and supporting one such insect, the iconic monarch butterfly (Danaus plexippus L.), as well as native bees in urban pollinator gardens. Wild-type Asclepias incarnata L. (swamp Milkweed) and Asclepias tuberosa L. (butterfly Milkweed) and three additional cultivars of each that vary in stature, floral display, and foliage color were grown in a replicated common garden experiment at a public arboretum. We monitored the plants for colonization by wild monarchs, assessed their suitability for supporting monarch larvae in greenhouse trials, measured their defensive characteristics (leaf trichome density, latex, and cardenolide levels), and compared the proportionate abundance and diversity of bee families and genera visiting their blooms. Significantly more monarch eggs and larvae were found on A. incarnata than A. tuberosa in both years, but within each Milkweed group, cultivars were colonized to the same extent as wild types. Despite some differences in defense allocation, all cultivars were as suitable as wild-type Milkweeds in supporting monarch larval growth. Five bee families and 17 genera were represented amongst the 2,436 total bees sampled from blooms of wild-type Milkweeds and their cultivars in the replicated gardens. Bee assemblages of A. incarnata were dominated by Apidae (Bombus, Xylocopa spp., and Apis mellifera), whereas A. tuberosa attracted relatively more Halictidae (especially Lasioglossum spp.) and Megachilidae. Proportionate abundance of bee families and genera was generally similar for cultivars and their respective wild types. This study suggests that, at least in small urban gardens, Milkweed cultivars can be as suitable as their parental species for supporting monarch butterflies and native bees.
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Colonization and usage of eight Milkweed (Asclepias) species by monarch butterflies and bees in urban garden settings
Journal of Insect Conservation, 2018Co-Authors: Adam M. Baker, Daniel A. PotterAbstract:Planting Milkweeds on public and private lands has emerged as a central conservation strategy for restoring declining North American migratory populations of the monarch butterfly ( Danaus plexippus ). Nearly all actionable science on this issue has focused on restoring common Milkweed ( Asclepias syriaca L.) in rural land types. The aim of this study was to develop recommendations for the best Milkweeds for managed gardens intended to support both monarch butterflies and bees. Eight Milkweed ( Asclepias ) species varying in height, form, and leaf shape were grown in a common-garden experiment at a public arboretum. We measured Milkweed growth, tillering, and bloom periods, conducted bi-weekly counts of eggs and larvae to assess colonization by wild monarchs, and evaluated suitability for growth of monarch larvae. We also quantified bee visitation and compared the bee assemblages associated with six of the eight species, augmented with additional collections from other sites. Monarchs rapidly colonized the gardens, but did not equally use all of the Milkweed species. More eggs and larvae were found on taller, broad-leaved Milkweeds, but there was relatively little difference in larval performance, suggesting ovipositional preference for more apparent plants. Asclepias tuberosa and A. fascicularis attracted the greatest number of bees, whereas bee genus diversity was greatest on A. verticillata, A. fascicularis , and A. tuberosa . Milkweeds that do not spread extensively by tillering may be best suited for managed gardens. Combining Milkweeds that are preferred by ovipositing monarchs with ones that are particularly attractive to bees may enhance conservation value of small urban gardens.
