Helen Michaels

• PhD Plant Biology, University of Illinois, Urbana
• Professor (Associate) at Bowling Green State University

Restoring critically imperiled midwestern oak savanna habitat is frequently guided by the requirements of the federally endangered Karner blue butterfly (Plebejus melissa samuelis). Although studies often correlate butterfly population size or density with nectar species abundance, nectar characteristics are seldom considered. We compared floral ne...

Phytophthora sojae is a major pathogen in cultivated soybeans world-wide. Although incorporating resistance genes has been an effective management tool for soybean breeders, surveys of soybean fields in the Midwest US indicate that some P. sojae strains are capable of overcoming all known resistance genes. While P. sojae is known to have a very nar...

Wild Lupine (Lupinus perennis) is an indicator of Midwestern U.S.A. oak savannas and the main larval food for endangered Karner Blue butterflies. In the past 100 y, this perennial has declined in distribution and abundance. To determine if this decline was related to population size and/or environmental factors and to better understand patterns of...

Premise of the study Understanding floral resources is vital for restoring pollinators in habitats affected by anthropogenic development and climate change. As the primary adult food, nectar can limit butterfly longevity and reproduction. For pollinator restoration, it would therefore be useful to examine nectar resources. However, because many flo...

Background Experimental manipulations of floral nectar in food deceptive species can reveal insights into the evolutionary consequences of the deceptive strategy. When coupled to pollen tracking, the effects of the deceptive pollination syndrome on both male and female reproductive success may be quantified. Attraction of pollinators in deceit-poll...

The effect of nectar addition, quadrat, number of stems, number of flowers and the distance of the three nearest non-orchid, nectar-producing neighbors on the percentage of total pollinia (R2 = 0.31), percent self pollinia (R2 = 0.41), and percent outcross pollinia received (R2 = 0.38). Percentage pollinia received calculated as the number of polli...

The effect of nectar addition, quadrat, number of stems, number of flowers and distance of the three nearest non-orchid, nectar-producing neighbors on percent fruit set (R2 = 0.34), and percent fruit abortion (R2 = 0.42). (PDF)

The effect of pollinia source, number of stems and number of flowers on the seed mass of a capsule, R2 = 0.067. (PDF)

Although hydroperiod and water chemistry are thought to control temporary wetland macroinvertebrate diversity, their effects are often only detected at the ends of hydrological and water quality gradients. However, canopy cover and other biotic factors dictate solar energy available for producer communities and limit food and shelter for consumers....

Ecological disturbances structure plant communities. In areas where reintroducing natural disturbances is unfeasible, land managers use artificial disturbances, such as fire and mowing, to simulate natural disturbances. However, prescribed fire and mowing can promote or inhibit seedling survival in plant populations. Lupinus perennis (the wild blue...

For many species of conservation significance, multiple factors limit reproduction. This research examines the contributions of plant height, number of flowers, number of stems, pollen limitation and seed predation to female reproductive success in the deceit-pollinated orchid, Cypripedium candidum. The deceptive pollination strategy employed by ma...

Background / Purpose: We wanted to determine if alydid insects have a preference for light or dark seeds in Lupinus perennis. We expected that dark seeds would contain chemical deterrents resulting in lower insect frequencies and less feeding. Main conclusion: There was an inverse relationship between alydid abundance and seed color, though fr...

Background / Purpose: We investigated two potential management strategies on an aquatic invasive species – flowering rush. Main conclusion: While clipping and flooding may not eradicate invasive populations of flowering rush, these management strategies may prevent further spread in the Great Lakes region.

Background/Question/Methods Attraction of pollinators in deceit-pollinated species often relies on producing a conspicuous floral display. Cypripedium candidum is a non-rewarding orchid that provides no nectar reward to floral visitors, but produces a variable number of single-flowered stems, depending on age and available resources. Higher numbe...

Background/Question/Methods Vernal pools are temporary wetlands that provide critical habitat for amphibians, macroinvertebrates, and plants because their seasonal drying prevents the establishment of predatory fish. Although highly valued for amphibian conservation, over 100 macroinvertebrate species use vernal pools and are important predators,...

Wild blue lupine (Lupinus perennis) in the Oak Openings Region of Northwest Ohio is an important nitrogen fixer and serves as an essential food source for the federally endangered Karner Blue butterfly (Lycaeides melissa samuelis). In order to examine potential factors that might be affecting mice predation on wild blue lupine seeds in oak savannas...

Background/Question/Methods Attempts to conserve threatened and endangered populations are often hindered by a lack of available data. Many long-lived clonal plants, and specifically terrestrial orchids, have faced decades of population decline and habitat loss, yet very little is known about their complete life history. To examine the demography...

Background/Question/Methods Terrestrial and aquatic systems are linked through an exchange of energy and materials. Despite this, many studies of vernal pools and other temporary wetlands have only focused on within-pool conditions, such as hydroperiod, water chemistry, and the presence of predator fauna. However, canopy cover may also influence...

Background/Question/Methods For many species of conservation significance, multiple factors limit reproduction. This research examines the contributions of pollinator attraction, successful pollen receipt, and granivory as limiting factors to reproduction in the White Lady’s Slipper Orchid, Cypripedium candidum Muhl ex Willd. Cypripedium spp. typ...

Background/Question/Methods Vernal pools are critically important habitats for many species of amphibians, invertebrates, and plants, such that one pool may have greater species diversity than the entire surrounding upland. Although the amphibian communities are widely studied, the macroinvertebrate communities are often ignored despite their roles...

Background/Question/Methods Elton’s diversity resistance hypothesis first advanced the notion that more diverse communities are likely to be more capable of resisting invasion. More recently, increased functional diversity as well as functional similarity of natives to invaders has also been suggested to promote invasion resistance. Teasel (Dipsa...

Background/Question/Methods Lupinus perennis (Wild blue lupine) is an integral part of midwestern oak savannah ecosystems. Because lupine provides food and habitat for the animals of the oak savannah, including several endangered or threatened butterflies, it is necessary to understand what happens to seeds after they disperse to determine the lon...

The Campanulaceae sensu stricto is an angiosperm family distributed primarily in north and south temperate regions with major centers of taxonomic diversity in Asia, Europe, North America, and South Africa. The family is comprised of 35 to 55 genera and approximately 1100 species. About one-third of the species of Campanulaceae are classified into...

The seven currently recognized species of Geranium endemic to the Hawaiian Islands are unusual in their shrubby or arborescent habit and unlobed, parallel-veined leaves rather than the palmately cleft or lobed leaves and herbaceous habit typical of the genus. Their placement within the genus and their biogeographic source have been obscured by this...

Nucleotide sequences of the chloroplast gene rbcL were analyzed to examine relationships among the large, distinctive family Asteraceae and eight putatively closely related families. Phylogenetic analysis of a total of 24 sequences of rbcL identified a lineage consisting of two families, the Goodeniaceae and Calyceraceae, as the sister group to the...

We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants, respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO or RuBPCase). We used two...

The Asteraceae are commonly divided into two large subfamilies, the Cichorioideae (syn. Lactucoideae; Mutisieae, Cardueae, Lactuceae, Vernonieae, Liabeae, Arctoteae) and the Asteroideae (Inuleae, Astereae, Anthemideae, Senecioneae, Calenduleae, Heliantheae, Eupatorieae). Recent phylogenetic analyses based on morphological and chloroplast DNA data c...

A parsimony analysis of 57 angiosperm rbcL sequences was conducted to test the monophyly of the Asteridae and to identify major lineages within the Asteridae. Three major clades, the Caryophyllidae, the Rosidae plus Dilleniidae, and the Asteridae sensu lato, emerge from an unresolved radiation in the "higher" dicots. The Asteridae sens. lat. includ...

Complete nucleotide sequences of the rbcL gene were obtained for 25 species of Asteraceae representing 15 of the currently recognized tribes and three outgroup families. A total of 345 variable nucleotide positions was identified, 170 of which were phylogenetically informative. Phylogenetic analyses of the rbcL data generated eight equally parsimon...

The sunflower family (Asteraceae) is one of the largest families of flowering plants, consisting of approximately 1,100 genera and 25,000 species (Jeffrey, 1978). The family has been variously divided into two or three subfamilies and 10 to 17 tribes (reviewed in Jansen et al., 1991a; Bremer, 1987). In addition to the disagreement concerning intraf...

Phylogenetic relationships among species representing 57 genera from 15 currently recognized tribes of Asteraceae were assessed by chloroplast DNA restriction site mapping. Phylogenetic analyses of 328 informative restriction site mutations were performed using both Dollo and Wagner parsimony and the bootstrap method. The results provide strong sup...

Chloroplast DNA variation was examined among 57 genera of Asteraceae representing 15 currently recognized tribes. Complete cleavage maps were constructed for 11 six-base pair restriction enzymes, and a total of 927 cleavage site differences was detected, 328 of which are phylogenetically informative. The data were used to construct phylogenetic tre...

Chloroplast DNA variation was examined among 57 genera of Asteraceae representing 15 currently recognized tribes. Complete cleavage maps were constructed for 11 six-base pair restriction enzymes, and a total of 927 cleavage site differences was detected, 328 of which are phylogenetically informative. The data were used to construct phylogenetic tre...

Several features, foremost its conservative mode of evolution, make chloroplast DNA an extremely valuable molecule for phylogenetic studies. Its conservatism is also its only serious drawback, as this can limit the amount of useful DNA variation at the intraspecific level. Comparative restriction site mapping is currently the preferred molecular me...

Apomictic plants produced more seeds per inflorescence, but their mean mass per seed was lower compared to sexual plants. However, because sexual seedling survivorship was higher than that of apomictic seedlings, the estimated numbers of offspring recruited, when male seedlings were included, were not different. Thus the primary difference in colon...

Although hybridization has been shown to be an important process in plant speciation, ascertaining the lineage of suspected hybrid individuals can be complicated when using morphological characters alone. While many F1 individuals may display the expected intermediacy in traits, repeated introgression may generate individuals that resemble the pare...