Host use in herbivores is determined by a variety of ecological drivers, including bottom-up and ... more Host use in herbivores is determined by a variety of ecological drivers, including bottom-up and top-down selective pressures such as host abundance, host plant quality, and parasitism pressure. If the relative importance and strength of interactions among these selective conditions change over an herbivore’s geographic range, local patterns of host use should change in response, evident in differing diet breadths. The fall webworm (Hyphantria cunea) is a widespread, polyphagous moth with two color morphs, red and black-headed. In the eastern United States, fall webworms feed on dozens of plant species and previous research demonstrated that host plant abundance was the only significant predictor of host plant use. Populations of fall webworm in Colorado are found on considerably fewer host plant species than populations farther east. We investigated the impacts of host abundance, larval performance, and parasitism on patterns of host use for fall webworm in Colorado to determine wh...
Dragonfly conservation in parks serves the dual purpose of protecting iconic species of aesthetic... more Dragonfly conservation in parks serves the dual purpose of protecting iconic species of aesthetic value to park visitors as well as preserving aquatic ecosystem function. The Hudsonian emerald dragonfly (Somatochlora hudsonica, Hagen). S. hudsonica is the only Colorado dragonfly listed as sensitive by the US Forest Service. Little is known about S. hudsonica’s habitat associations, distribution, and life history, all essential for future management of the species. We began answering those basic questions with literature-based habitat suitability models followed by a ground-truthing survey of adults across Boulder County Parks and Open Space (BCPOS) properties that span the suitability gradient to determine the local habitat variables that influence probability of occurrence. To determine breeding habitat, we also conducted an exuvial survey, and set the groundwork for captive rearing. The information collected as part of this project will provide critical baseline data necessary for...
Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species that is ... more Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species that is polyphagous over its entire range, but populations appear to have become more specialized within specific regions. For instance, in Colorado fall webworm feeds on ~17 different host plants whereas populations farther east can be found feeding on dozens of hosts. One host plant for fall webworm in Colorado is plains cottonwood (Populus deltoides). Fall webworm larvae are not as likely to feed on plains cottonwood located on the canyons in the foothills of Colorado, as they are to feed on plains cottonwood located on the adjacent plains. Furthermore, plains cottonwood is never as commonly used as a host as its congener, narrowleaf cottonwood (Populus angustifolia), which is a relatively high-quality host for fall webworm in Colorado. We investigated this intra- and inter-specific variation in host use and tested whether fall webworm larval performance varied among cottonwood populations an...
Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species whose la... more Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species whose larvae have been found to feed on >100 plant species. In Colorado, fall webworm larvae feed on ~17 different host plants of varying nutritional quality. Studies on other insects have shown that some species can compensate for feeding on poor-quality hosts early in their development by switching to a higher-quality host later in life. We tested whether fall webworm larvae are capable of compensatory growth by rearing them on hosts that varied in quality and by switching larvae from low-quality to higher-quality hosts midway through development. We used chokecherry (Prunus virginiana) as a high-quality host, narrowleaf cottonwood (Populus angustifolia) and alder (Alnus tenuifolia) as medium-quality hosts, and crabapple (Malus sp.) as a low-quality host. Using a split-brood design, we reared larvae either entirely on one of the four host plants or switched them part way through their devel...
Background/Question/Methods Natural enemies and host plant quality have both been invoked to expl... more Background/Question/Methods Natural enemies and host plant quality have both been invoked to explain the evolution of host choice in herbivorous insects. In this study, we quantified both selection pressures for a polyphagous moth species, fall webworm (Hyphantria cunea Drury). The gregarious larvae spin extensive webs for protection and thermoregulation. Fall webworm have been recorded on dozens of plant families worldwide. In Colorado, we have observed and collected the larvae from ~17 host species. As part of an observational study, in 2010 and 2011 we collected wild larvae from multiple field sites in Colorado, returned them to the lab to finish their development and reared out any parasitoids in order to quantify host plant quality and parasitism pressure for each host plant species. In 2011, we selected four host plants of high and low host plant quality, based on results from our observational study in 2010 for a manipulative split-brood experiment in the lab. Our two high-qu...
The fall webworm (Hyphantria cunea Drury) is a moth species native to North America and an invasi... more The fall webworm (Hyphantria cunea Drury) is a moth species native to North America and an invasive pest in Europe and Asia. Hyphantria cunea larvae are noted generalists, and have been recorded feeding on dozens of plant families worldwide. There appear to be at least two forms of H. cunea that are distinguished by the larval head capsule color: black or red. Most previous accounts of H. cunea in the literature focus on the black-headed form. The three goals of the research we present here are to 1) detail successful rearing techniques for the red-headed form of H. cunea, 2) describe life history traits of red-headed H. cunea in Colorado and 3) test whether female pupal mass predicts potential fecundity for H. cunea as well as other lepidopteran species. Our data are compiled from two years of rearing experiments in the lab. In addition, we compare measures of life history traits from our research with those of other collections of H. cunea from Asia, Europe, Canada, and other regions of the United States to enable a better comparison between the black-headed and red-headed forms of H. cunea.
Host use in herbivores is determined by a variety of ecological drivers, including bottom-up and ... more Host use in herbivores is determined by a variety of ecological drivers, including bottom-up and top-down selective pressures such as host abundance, host plant quality, and parasitism pressure. If the relative importance and strength of interactions among these selective conditions change over an herbivore’s geographic range, local patterns of host use should change in response, evident in differing diet breadths. The fall webworm (Hyphantria cunea) is a widespread, polyphagous moth with two color morphs, red and black-headed. In the eastern United States, fall webworms feed on dozens of plant species and previous research demonstrated that host plant abundance was the only significant predictor of host plant use. Populations of fall webworm in Colorado are found on considerably fewer host plant species than populations farther east. We investigated the impacts of host abundance, larval performance, and parasitism on patterns of host use for fall webworm in Colorado to determine wh...
Dragonfly conservation in parks serves the dual purpose of protecting iconic species of aesthetic... more Dragonfly conservation in parks serves the dual purpose of protecting iconic species of aesthetic value to park visitors as well as preserving aquatic ecosystem function. The Hudsonian emerald dragonfly (Somatochlora hudsonica, Hagen). S. hudsonica is the only Colorado dragonfly listed as sensitive by the US Forest Service. Little is known about S. hudsonica’s habitat associations, distribution, and life history, all essential for future management of the species. We began answering those basic questions with literature-based habitat suitability models followed by a ground-truthing survey of adults across Boulder County Parks and Open Space (BCPOS) properties that span the suitability gradient to determine the local habitat variables that influence probability of occurrence. To determine breeding habitat, we also conducted an exuvial survey, and set the groundwork for captive rearing. The information collected as part of this project will provide critical baseline data necessary for...
Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species that is ... more Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species that is polyphagous over its entire range, but populations appear to have become more specialized within specific regions. For instance, in Colorado fall webworm feeds on ~17 different host plants whereas populations farther east can be found feeding on dozens of hosts. One host plant for fall webworm in Colorado is plains cottonwood (Populus deltoides). Fall webworm larvae are not as likely to feed on plains cottonwood located on the canyons in the foothills of Colorado, as they are to feed on plains cottonwood located on the adjacent plains. Furthermore, plains cottonwood is never as commonly used as a host as its congener, narrowleaf cottonwood (Populus angustifolia), which is a relatively high-quality host for fall webworm in Colorado. We investigated this intra- and inter-specific variation in host use and tested whether fall webworm larval performance varied among cottonwood populations an...
Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species whose la... more Background/Question/Methods Fall webworm (Hyphantria cunea) is a generalist moth species whose larvae have been found to feed on >100 plant species. In Colorado, fall webworm larvae feed on ~17 different host plants of varying nutritional quality. Studies on other insects have shown that some species can compensate for feeding on poor-quality hosts early in their development by switching to a higher-quality host later in life. We tested whether fall webworm larvae are capable of compensatory growth by rearing them on hosts that varied in quality and by switching larvae from low-quality to higher-quality hosts midway through development. We used chokecherry (Prunus virginiana) as a high-quality host, narrowleaf cottonwood (Populus angustifolia) and alder (Alnus tenuifolia) as medium-quality hosts, and crabapple (Malus sp.) as a low-quality host. Using a split-brood design, we reared larvae either entirely on one of the four host plants or switched them part way through their devel...
Background/Question/Methods Natural enemies and host plant quality have both been invoked to expl... more Background/Question/Methods Natural enemies and host plant quality have both been invoked to explain the evolution of host choice in herbivorous insects. In this study, we quantified both selection pressures for a polyphagous moth species, fall webworm (Hyphantria cunea Drury). The gregarious larvae spin extensive webs for protection and thermoregulation. Fall webworm have been recorded on dozens of plant families worldwide. In Colorado, we have observed and collected the larvae from ~17 host species. As part of an observational study, in 2010 and 2011 we collected wild larvae from multiple field sites in Colorado, returned them to the lab to finish their development and reared out any parasitoids in order to quantify host plant quality and parasitism pressure for each host plant species. In 2011, we selected four host plants of high and low host plant quality, based on results from our observational study in 2010 for a manipulative split-brood experiment in the lab. Our two high-qu...
The fall webworm (Hyphantria cunea Drury) is a moth species native to North America and an invasi... more The fall webworm (Hyphantria cunea Drury) is a moth species native to North America and an invasive pest in Europe and Asia. Hyphantria cunea larvae are noted generalists, and have been recorded feeding on dozens of plant families worldwide. There appear to be at least two forms of H. cunea that are distinguished by the larval head capsule color: black or red. Most previous accounts of H. cunea in the literature focus on the black-headed form. The three goals of the research we present here are to 1) detail successful rearing techniques for the red-headed form of H. cunea, 2) describe life history traits of red-headed H. cunea in Colorado and 3) test whether female pupal mass predicts potential fecundity for H. cunea as well as other lepidopteran species. Our data are compiled from two years of rearing experiments in the lab. In addition, we compare measures of life history traits from our research with those of other collections of H. cunea from Asia, Europe, Canada, and other regions of the United States to enable a better comparison between the black-headed and red-headed forms of H. cunea.
Uploads
Papers by Katrina Loewy