Flowering rush (Butomus umbellatus) is an invasive aquatic plant introduced to North America from... more Flowering rush (Butomus umbellatus) is an invasive aquatic plant introduced to North America from Eurasia in 1897. Flowering rush can grow either submersed or emergent from wet soil habitats to waters that are up to 5 m deep. Flowering rush was first observed in the Detroit Lake system in the 1960s, causing significant impact to shoreline and recreational use. Flowering rush is currently found in five basins of the Detroit Lake system: Big Detroit, Little Detroit, Curfman, Sallie, and Melissa Lakes. Submersed treatments with diquat were used during 2012 on an operational scale to control the nuisance impacts of flowering rush in waters from 0 to 1.3 m deep. We evaluated the response of native plant communities with the use of a point intercept method on 30 or more predetermined points in each of nine treatment plots, with four untreated reference plots. Treatment plots were sampled before treatment (June), and 4 wk after each of the two treatments. We also sampled 20 biomass cores (0.018 m-2) in each of four treatment and four untreated reference plots. Although some species declined after treatment, most native species did not change significantly after treatments compared to untreated reference plots. Treatments with diquat not only significantly reduce flowering rush distribution (60%) and aboveground biomass (99%), but also significantly reduced belowground biomass (82%) and rhizome bud density (83%). As flowering rush is an herbaceous perennial that propagates predominantly by rhizome buds, reductions in rhizome bud density indicate that this approach can be used for long-term reduction in flowering rush populations.
The host range expansion of the specialist milfoil weevil, Euhrychiopsis lecontei, from the nativ... more The host range expansion of the specialist milfoil weevil, Euhrychiopsis lecontei, from the native Myriophyllum sibiricum (northern watermilfoil) to invasive M. spicatum (Eurasian watermilfoil) is one of the few examples of a native insect herbivore preferring, growing and surviving better on a nonindigenous host plant than it does on its native host plant. The milfoil weevil’s preference for the nonindigenous plant can be induced during juvenile development or through exposure to Eurasian watermilfoil as an adult. We evaluated how the fecundity of the milfoil weevil was affected over time by juvenile and adult exposure to the native, invasive and invasive × native hybrid milfoils and whether fecundity was correlated with host plant quality. Weevils reared on Eurasian watermilfoil laid more eggs than those reared on northern or hybrid watermilfoils. When weevils were collected from and exposed to milfoils collected directly from a lake, Eurasian-reared weevils had higher fecundity and greater preference for Eurasian over northern watermilfoil. When weevils were reared on and allowed to oviposit on milfoils grown in a common environment, the differences in fecundity and preference for Eurasian over northern or hybrid watermilfoils diminished. In Eurasian-northern experiments, milfoil weevils laid more than 80% of their eggs on Eurasian watermilfoil, but that value decreased when plants from common environments were used. Despite this preference, most weevils continued to use both hosts indicating that a complete host switch is unlikely. Weevils showed no oviposition preference between Eurasian and hybrid milfoils. The milfoil weevil had higher fecundity on Eurasian watermilfoil, which had a higher concentration of carbon, polyphenols and lignin than did northern watermilfoil, which had a higher concentration of ash. The milfoil weevil’s preference for Eurasian watermilfoil was affected by changes in plant chemistry, and ash appeared to act as a deterrent to oviposition on northern watermilfoil. The milfoil weevil can modify its response based on host-plant chemistry.
Myriophyllum spicatum or Eurasian watermilfoil (hereafter, milfoil) is among the most problematic... more Myriophyllum spicatum or Eurasian watermilfoil (hereafter, milfoil) is among the most problematic invasive aquatic plant species throughout much of North America. M. spicatum infestations can result in reduced diversity and abundance of native plant populations. Control of the invader is essential to promoting healthy ecosystems. Several treatment alternatives are available for milfoil control, although cost and efficacy vary significantly, with some treatments resulting in more harm to the native population than no treatment at all. A series of field-based microcosms containing actively growing milfoil were constructed in order to directly compare the impact of two herbicides (2,4-dichlorophenoxyacetic acid and fluridone) and the milfoil weevil (Euhrychiopsis lecontei) on weed control and plant biochemistry. Herbicide concentrations in water, plants, and sediments were monitored, as were weevil population dynamics and resulting invertebrate damage to milfoil stems. The impact of the different treatments on levels of polyphenols, carbohydrates, ash, and overall carbon and nitrogen levels in the milfoil were determined. Total biomass of the untreated milfoil increased by more than 2.7-fold during the 53-day experimental period. Conversely, the biomass of milfoil subjected to chemical or biological treatment either remained constant or decreased significantly during the experiment. The herbicide 2,4-D resulted in nearly 100% milfoil mortality by day 20, whereas fluridone toxicity was significantly slower but reached 75% by the end of the trial. Similarly, milfoil growth in the weevil-amended tanks was somewhat erratic but by the end of the trial, the total plant biomass was 71% less than that of un-amended controls. Although the total biomass remaining at the end of the fluridone and weevil treatments was similar, the carbohydrate and starch content of the shoots in the insect treatment were nearly 4.6- and 4.8-fold greater, respectively, than that of the herbicide treated plants. The higher starch content in insect-treated plants could lead to increased autofragmentation and spread of M. spicatum. However, herbicide treatments are frequently required for several years. Therefore, integrated pest management, which combines the long-term benefits of biological controls with the short-term benefits of herbicides may provide the best solution to the control of M. spicatum and the conservation of native plants.
Flowering rush, Butomus umbellatus L., has been an increasing problem in the Detroit Lakes chain ... more Flowering rush, Butomus umbellatus L., has been an increasing problem in the Detroit Lakes chain of lakes for more than 40 yr. Flowering rush dominates ecosystems by crowding out native species, including hardstem bulrush, Schoenoplectus acutus (Muhl. ex Bigelow) A & D L ¨ ove, a vital part of native ecosystems. Furthermore, flowering rush creates boating hazards and hampers recreational activities on the lakes. The phenological differences between flowering rush and the native hardstem bulrush were examined as part of a project to determine best management practices for controlling this invasive species. Biomass allocation, plant height, carbohydrate allocation, and reproductive structures of flowering rush were examined in the Detroit Lakes system. Flowering rush and hardstem bulrush exhibited similar times of emergence, maximal growth, and senescence, thus requiring careful management to protect the native species. Hardstem bulrush was approximately 1 m taller than flowering rush during midsummer. Flowering rush continually formed rhizome buds as its primary mode of reproduction, and approximately one bud for every 2 g of rhizome, or 393 buds m À2 , were produced within the midst of a flowering rush bed. These high densities of rhizome buds could lead to further spread of flowering rush as well as require long-term treatment of this propagule bank. The number of leaves sprouting from rhizomes was greatest in midsummer in both 2010 and 2011. Throughout summer, 69% of the biomass of flowering rush plants was found below ground, indicating treatment efforts will need to target a reduction of belowground material, potentially over several years.
The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits... more The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits, and mates on the invasive freshwater macrophyte Myriophyllum spicatum. We characterized the weevil's preference for M. spicatum, and through bioassay-driven fractionation, isolated and identified two chemicals released by M. spicatum that attract E. lecontei. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify the attractive compounds as glycerol and uracil. Dose-response curves for glycerol and uracil indicated that weevil preference increased as sample concentration increased. Weevils were attracted to a crude sample of M. spicatum-released chemicals from 0.17 to 17 mg/l, to glycerol from 18 to 1800 microM (0.0017-0.17 mg/l), and to uracil from 0.015 to 15 microM (0.00014-1.4 mg/l). Although glycerol and uracil are ubiquitous, weevils are likely responding to high concentrations that are released as a result of the rapid growth of M. spicatum. Uracil concentration was greater in the exudates of M. spicatum than other Myriophyllum spp. E. lecontei was attracted to glycerol at a concentration similar to that at which terrestrial insects are attracted to sugar alcohols. This is the first example of a freshwater specialist insect being attracted to chemicals released by its host plant. Analysis of the water milfoil-weevil interaction provides further understanding as to how insects locate their host plants in aquatic systems.
Background/Question/Methods Invasive species are a threat to ecosystems and human use of these ec... more Background/Question/Methods Invasive species are a threat to ecosystems and human use of these ecosystems. In the context of climate change, habitat fragmentation and pollution, these threats are even more pronounced. Managing the impacts of invasive species, under the auspices of our environmental challenges requires the careful consideration of organism ecology and phenology. When a new invader enters a region, lake managers often move quickly to treat the problem. This may involve a quick analysis of effective and acceptable herbicides and appropriate use. However, a clearer understanding of the invading plant’s ecology and phenology and interactions with native species may ultimately lead to more rapid control of the invader. The invasive plant flowering rush (Butomus umbellatus) is a growing problem around the Great Lakes, northwestern United States and several sites in Minnesota. Flowering rush has been a pervasive problem in the Detroit Lakes chain of lakes in northern Minnes...
The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits... more The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits, and mates on the invasive freshwater macrophyte Myriophyllum spicatum. We characterized the weevil's preference for M. spicatum, and through bioassay-driven fractionation, isolated and identified two chemicals released by M. spicatum that attract E. lecontei. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify the attractive compounds as glycerol and uracil. Dose-response curves for glycerol and uracil indicated that weevil preference increased as sample concentration increased. Weevils were attracted to a crude sample of M. spicatum-released chemicals from 0.17 to 17 mg/l, to glycerol from 18 to 1800 microM (0.0017-0.17 mg/l), and to uracil from 0.015 to 15 microM (0.00014-1.4 mg/l). Although glycerol and uracil are ubiquitous, weevils are likely responding to high concentrations that are released as a result of the rapid growth of M. spicatum. Uracil concentration was greater in the exudates of M. spicatum than other Myriophyllum spp. E. lecontei was attracted to glycerol at a concentration similar to that at which terrestrial insects are attracted to sugar alcohols. This is the first example of a freshwater specialist insect being attracted to chemicals released by its host plant. Analysis of the water milfoil-weevil interaction provides further understanding as to how insects locate their host plants in aquatic systems.
This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nu... more This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium da...
Flowering rush (Butomus umbellatus) is an invasive aquatic plant introduced to North America from... more Flowering rush (Butomus umbellatus) is an invasive aquatic plant introduced to North America from Eurasia in 1897. Flowering rush can grow either submersed or emergent from wet soil habitats to waters that are up to 5 m deep. Flowering rush was first observed in the Detroit Lake system in the 1960s, causing significant impact to shoreline and recreational use. Flowering rush is currently found in five basins of the Detroit Lake system: Big Detroit, Little Detroit, Curfman, Sallie, and Melissa Lakes. Submersed treatments with diquat were used during 2012 on an operational scale to control the nuisance impacts of flowering rush in waters from 0 to 1.3 m deep. We evaluated the response of native plant communities with the use of a point intercept method on 30 or more predetermined points in each of nine treatment plots, with four untreated reference plots. Treatment plots were sampled before treatment (June), and 4 wk after each of the two treatments. We also sampled 20 biomass cores (0.018 m-2) in each of four treatment and four untreated reference plots. Although some species declined after treatment, most native species did not change significantly after treatments compared to untreated reference plots. Treatments with diquat not only significantly reduce flowering rush distribution (60%) and aboveground biomass (99%), but also significantly reduced belowground biomass (82%) and rhizome bud density (83%). As flowering rush is an herbaceous perennial that propagates predominantly by rhizome buds, reductions in rhizome bud density indicate that this approach can be used for long-term reduction in flowering rush populations.
The host range expansion of the specialist milfoil weevil, Euhrychiopsis lecontei, from the nativ... more The host range expansion of the specialist milfoil weevil, Euhrychiopsis lecontei, from the native Myriophyllum sibiricum (northern watermilfoil) to invasive M. spicatum (Eurasian watermilfoil) is one of the few examples of a native insect herbivore preferring, growing and surviving better on a nonindigenous host plant than it does on its native host plant. The milfoil weevil’s preference for the nonindigenous plant can be induced during juvenile development or through exposure to Eurasian watermilfoil as an adult. We evaluated how the fecundity of the milfoil weevil was affected over time by juvenile and adult exposure to the native, invasive and invasive × native hybrid milfoils and whether fecundity was correlated with host plant quality. Weevils reared on Eurasian watermilfoil laid more eggs than those reared on northern or hybrid watermilfoils. When weevils were collected from and exposed to milfoils collected directly from a lake, Eurasian-reared weevils had higher fecundity and greater preference for Eurasian over northern watermilfoil. When weevils were reared on and allowed to oviposit on milfoils grown in a common environment, the differences in fecundity and preference for Eurasian over northern or hybrid watermilfoils diminished. In Eurasian-northern experiments, milfoil weevils laid more than 80% of their eggs on Eurasian watermilfoil, but that value decreased when plants from common environments were used. Despite this preference, most weevils continued to use both hosts indicating that a complete host switch is unlikely. Weevils showed no oviposition preference between Eurasian and hybrid milfoils. The milfoil weevil had higher fecundity on Eurasian watermilfoil, which had a higher concentration of carbon, polyphenols and lignin than did northern watermilfoil, which had a higher concentration of ash. The milfoil weevil’s preference for Eurasian watermilfoil was affected by changes in plant chemistry, and ash appeared to act as a deterrent to oviposition on northern watermilfoil. The milfoil weevil can modify its response based on host-plant chemistry.
Myriophyllum spicatum or Eurasian watermilfoil (hereafter, milfoil) is among the most problematic... more Myriophyllum spicatum or Eurasian watermilfoil (hereafter, milfoil) is among the most problematic invasive aquatic plant species throughout much of North America. M. spicatum infestations can result in reduced diversity and abundance of native plant populations. Control of the invader is essential to promoting healthy ecosystems. Several treatment alternatives are available for milfoil control, although cost and efficacy vary significantly, with some treatments resulting in more harm to the native population than no treatment at all. A series of field-based microcosms containing actively growing milfoil were constructed in order to directly compare the impact of two herbicides (2,4-dichlorophenoxyacetic acid and fluridone) and the milfoil weevil (Euhrychiopsis lecontei) on weed control and plant biochemistry. Herbicide concentrations in water, plants, and sediments were monitored, as were weevil population dynamics and resulting invertebrate damage to milfoil stems. The impact of the different treatments on levels of polyphenols, carbohydrates, ash, and overall carbon and nitrogen levels in the milfoil were determined. Total biomass of the untreated milfoil increased by more than 2.7-fold during the 53-day experimental period. Conversely, the biomass of milfoil subjected to chemical or biological treatment either remained constant or decreased significantly during the experiment. The herbicide 2,4-D resulted in nearly 100% milfoil mortality by day 20, whereas fluridone toxicity was significantly slower but reached 75% by the end of the trial. Similarly, milfoil growth in the weevil-amended tanks was somewhat erratic but by the end of the trial, the total plant biomass was 71% less than that of un-amended controls. Although the total biomass remaining at the end of the fluridone and weevil treatments was similar, the carbohydrate and starch content of the shoots in the insect treatment were nearly 4.6- and 4.8-fold greater, respectively, than that of the herbicide treated plants. The higher starch content in insect-treated plants could lead to increased autofragmentation and spread of M. spicatum. However, herbicide treatments are frequently required for several years. Therefore, integrated pest management, which combines the long-term benefits of biological controls with the short-term benefits of herbicides may provide the best solution to the control of M. spicatum and the conservation of native plants.
Flowering rush, Butomus umbellatus L., has been an increasing problem in the Detroit Lakes chain ... more Flowering rush, Butomus umbellatus L., has been an increasing problem in the Detroit Lakes chain of lakes for more than 40 yr. Flowering rush dominates ecosystems by crowding out native species, including hardstem bulrush, Schoenoplectus acutus (Muhl. ex Bigelow) A & D L ¨ ove, a vital part of native ecosystems. Furthermore, flowering rush creates boating hazards and hampers recreational activities on the lakes. The phenological differences between flowering rush and the native hardstem bulrush were examined as part of a project to determine best management practices for controlling this invasive species. Biomass allocation, plant height, carbohydrate allocation, and reproductive structures of flowering rush were examined in the Detroit Lakes system. Flowering rush and hardstem bulrush exhibited similar times of emergence, maximal growth, and senescence, thus requiring careful management to protect the native species. Hardstem bulrush was approximately 1 m taller than flowering rush during midsummer. Flowering rush continually formed rhizome buds as its primary mode of reproduction, and approximately one bud for every 2 g of rhizome, or 393 buds m À2 , were produced within the midst of a flowering rush bed. These high densities of rhizome buds could lead to further spread of flowering rush as well as require long-term treatment of this propagule bank. The number of leaves sprouting from rhizomes was greatest in midsummer in both 2010 and 2011. Throughout summer, 69% of the biomass of flowering rush plants was found below ground, indicating treatment efforts will need to target a reduction of belowground material, potentially over several years.
The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits... more The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits, and mates on the invasive freshwater macrophyte Myriophyllum spicatum. We characterized the weevil's preference for M. spicatum, and through bioassay-driven fractionation, isolated and identified two chemicals released by M. spicatum that attract E. lecontei. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify the attractive compounds as glycerol and uracil. Dose-response curves for glycerol and uracil indicated that weevil preference increased as sample concentration increased. Weevils were attracted to a crude sample of M. spicatum-released chemicals from 0.17 to 17 mg/l, to glycerol from 18 to 1800 microM (0.0017-0.17 mg/l), and to uracil from 0.015 to 15 microM (0.00014-1.4 mg/l). Although glycerol and uracil are ubiquitous, weevils are likely responding to high concentrations that are released as a result of the rapid growth of M. spicatum. Uracil concentration was greater in the exudates of M. spicatum than other Myriophyllum spp. E. lecontei was attracted to glycerol at a concentration similar to that at which terrestrial insects are attracted to sugar alcohols. This is the first example of a freshwater specialist insect being attracted to chemicals released by its host plant. Analysis of the water milfoil-weevil interaction provides further understanding as to how insects locate their host plants in aquatic systems.
Background/Question/Methods Invasive species are a threat to ecosystems and human use of these ec... more Background/Question/Methods Invasive species are a threat to ecosystems and human use of these ecosystems. In the context of climate change, habitat fragmentation and pollution, these threats are even more pronounced. Managing the impacts of invasive species, under the auspices of our environmental challenges requires the careful consideration of organism ecology and phenology. When a new invader enters a region, lake managers often move quickly to treat the problem. This may involve a quick analysis of effective and acceptable herbicides and appropriate use. However, a clearer understanding of the invading plant’s ecology and phenology and interactions with native species may ultimately lead to more rapid control of the invader. The invasive plant flowering rush (Butomus umbellatus) is a growing problem around the Great Lakes, northwestern United States and several sites in Minnesota. Flowering rush has been a pervasive problem in the Detroit Lakes chain of lakes in northern Minnes...
The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits... more The milfoil weevil Euhrychiopsis lecontei is a specialist aquatic herbivore that feeds, oviposits, and mates on the invasive freshwater macrophyte Myriophyllum spicatum. We characterized the weevil's preference for M. spicatum, and through bioassay-driven fractionation, isolated and identified two chemicals released by M. spicatum that attract E. lecontei. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify the attractive compounds as glycerol and uracil. Dose-response curves for glycerol and uracil indicated that weevil preference increased as sample concentration increased. Weevils were attracted to a crude sample of M. spicatum-released chemicals from 0.17 to 17 mg/l, to glycerol from 18 to 1800 microM (0.0017-0.17 mg/l), and to uracil from 0.015 to 15 microM (0.00014-1.4 mg/l). Although glycerol and uracil are ubiquitous, weevils are likely responding to high concentrations that are released as a result of the rapid growth of M. spicatum. Uracil concentration was greater in the exudates of M. spicatum than other Myriophyllum spp. E. lecontei was attracted to glycerol at a concentration similar to that at which terrestrial insects are attracted to sugar alcohols. This is the first example of a freshwater specialist insect being attracted to chemicals released by its host plant. Analysis of the water milfoil-weevil interaction provides further understanding as to how insects locate their host plants in aquatic systems.
This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nu... more This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium da...
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