Heritability of Nectar Traits: Why Do We Know So Little?

Although floral and extrafloral nectar traits are important for plant reproduction and defense, we know little about their genetic basis. Only a handful of studies have quantified heritable variation for nectar traits, primarily in controlled environments that minimize environmental variation. Most such studies have reported strong genetic influences, with heritabilities often \u3e0.35. However, because nectar traits are often very responsive to environmental variation, even substantial amounts of genetic variation may be swamped out in the,field. Environmental variation deserves to be studied in its own right, including exploration of genotype X environment interaction for nectar traits . Most genetic studies of nectar have focused on production rate and concentration, whereas we know almost nothing about the heritability of other important traits such as production patterns, sugar ratios, amino acid composition, taste, and scent. Likewise, almost nothing is known about the heritability of extrafloral nectar traits. Important progress on all of these fronts can be made using simple experimental designs to quantify environmental effects, genotype X environment interactions, clonal repeatability, and correlated traits. There is great promise in molecular approaches, but their use will not obviate the need for more quantitative genetic studies in the field and greenhouse

Occurrence of Two Species of Old World Bees, \u3ci\u3eAnthidium Manicatum\u3c/i\u3e and \u3ci\u3eA. Oblongatum\u3c/i\u3e (Apoidea: Megachilidae), in Northern Ohio and Southern Michigan

Anthidium manicatum and A. oblongatum are two European bees species that have recently established themselves in North America. Anthidium manicatum has previously been documented in New York and Ontario, Canada, and A. oblongatum has been documented in New York, New Jersey, Maryland, and eastern Pennsylvania. We surveyed a number of sites in Ohio, Michigan, and Indiana for these species in 2000 and 2001, and found both bee species to have extended their ranges into northern Ohio, and A. manicatum to have moved into southern Michigan. We present a key identifying the four Anthidium species now known from northeastern North America

Effects of Local Conspecific Density on Reproductive Success in Penstemon Digitalis and Hesperis Matronalis

Author Institution: Department of Biology, University of AkronWe investigated the effects of plant density on reproductive success for two insect-pollinated plant species—the native North American wildflower Penstemon digitalis (Foxglove-leaved Penstemon), and the showy introduced weed Hesperis matronalis (Dame's Rocket). We found no indication that local density (within 3.0 m) affected reproductive success (seeds per fruit, proportion fruit set, total seeds per plant) for either species. Penstemon digitalis suffered heavy fruit predation from micro-lepidopterans, and such damage tended non-significantly to increase with density. We discuss the reasons for our results, and suggest that an understanding of those causes is important for conservation

Direction-Dependent Polarised Primary Beams in Wide-Field Synthesis Imaging

The process of wide-field synthesis imaging is explored, with the aim of understanding the implications of variable, polarised primary beams for forthcoming Epoch of Reionisation experiments. These experiments seek to detect weak signatures from redshifted 21cm emission in deep residual datasets, after suppression and subtraction of foreground emission. Many subtraction algorithms benefit from low side-lobes and polarisation leakage at the outset, and both of these are intimately linked to how the polarised primary beams are handled. Building on previous contributions from a number of authors, in which direction-dependent corrections are incorporated into visibility gridding kernels, we consider the special characteristics of arrays of fixed dipole antennas operating around 100-200 MHz, looking towards instruments such as the Square Kilometre Array (SKA) and the Hydrogen Epoch of Reionization Arrays (HERA). We show that integrating snapshots in the image domain can help to produce compact gridding kernels, and also reduce the need to make complicated polarised leakage corrections during gridding. We also investigate an alternative form for the gridding kernel that can suppress variations in the direction-dependent weighting of gridded visibilities by 10s of dB, while maintaining compact support.Comment: 15 pages, 4 figures. Accepted for publication in JA

Competition for Pollination Between an Invasive Species (Purple Loosestrife) and a Native Congener

Invasive species are frequently regarded as Superlative competitors that can vegetatively crowd Out natives, but little is known about whether invasives call compete for pollination services with native plants. We hypothesized that, when the showy invasive species Lythrum salicaria (purple loosestrife) was present, pollinator visitation and seed set would be reduced in a native congener, L. alatum (winged loosestrife). To test this hypothesis, we constructed mixed and monospecific plots of the two species. Over two years of study, we found that L. salicaria significantly reduced both pollinator visitation and seed set in L. alatum. Furthermore, pollinators moved frequently between the two plant species, which may cause heterospecific pollen transfer. Thus, reductions in both pollen quantity and pollen quality may reduce L. alatum seed set. If similar patterns occur in the field, invasive plants may be an even greater threat to natives than previously thought

Effects of Population Size and Density On Pollinator Visitation, Pollinator Behavior, and Pollen Tube Abundance in Lupinus Perennis

Both the number and the density of flowering plants in a population can be important determinants of pollinator abundance and behavior. We report the joint effects of population size and density on pollinator visitation and pollination success for Lupinus perennis (Fabaceae). Focusing on five pairs of populations, we matched one small population (125-800 flowering plants) with one distinctly larger population (1000-3000 flowering plants). In these pairs, population size did not affect pollinator communities or pollination success. All measures of pollination success increased significantly with density. Only bee behavior (number of flowers probed per inflorescence) exhibited a significant interaction of size and density. Testing whether population sizes smaller than those in the paired populations might affect pollination, we gathered pollen tube samples from 14 unpaired populations (16-215 flowering plants). Combining these data with those from the paired populations revealed a significant decrease in pollination for smaller populations, indicating that effects of population size may be detectable only when populations smaller than a few hundred plants are sampled. We found that effects of density are consistent and much stronger than those of population size. Our results suggest that both size and density of natural populations should be considered in designing restoration and reintroduction programs for this threatened plant

Perceived Differences in Knowledge About Interactive Technology Between Young Adults and Their Parents

This study was designed to investigate generational differences in knowledge about interactive technology (i.e., cell phones, social networking, email, video chat) between parents and their young adult children. Parents (n = 555) and young adults (n = 604) residing in the United States provided information about their knowledge in the use of interactive technology. Young adult children also reported their perceptions of their parents’ technological knowledge for the various technologies. Comparisons of young adult self-reported technological knowledge and their parents’ own reports of technological knowledge revealed that young adults were perceived to be much more knowledgeable than their parents (by both the young adults and their parents) regardless of the technology medium. The largest differences between parents and their young adult children were associated with newer interactive technologies, with the largest gap between parent and young adult knowledge in the area of social networking. Perceived differences between parents and their young adult children were smaller among the technologies that have been in use longer (such as such as e-mail), and larger among the newer modes of interactive technology (e.g., video chat)

Pollinator Selection, Quantitative Genetics, and Predicted Evolutionary Responses of Floral Traits in Penstemon Centranthifolius (Scrophulariaceae)

Much of the remarkable diversity of angiosperm flowers is thought to have evolved in response to selection by animal pollinators. Selection during pollination can readily be documented, but the extent to which it leads to evolutionary change depends on the genetic basis of floral traits. Here we combine estimates of genetic variance and covariance for several traits of flowers and inflorescences in a wild plant species, with estimates of natural selection by hummingbird pollinators. Analysis of phenotypic selection through two components of pollination success indicates direct selection of plants toward larger size and toward bearing shorter flowers that produce more nectar. Predictions of selection response that account for genetic correlations among traits generally exceed the simple predictions based on apparent selection and heritabilities of single traits. This underscores the importance of genetic correlations and demonstrates that univariate, strictly phenotypic, analyses of natural selection can be misleading. A sample of fruits from one of the two years of our study also indicates that total selection at the end of the reproductive cycle is weaker than selection during pollination. Thus a second caution is in order, against relying too strongly on differential pollination success as an estimate of overall selection

Interspecific Competition for Pollination Lowers Seed Production and Outcrossing in Mimulus Ringens

Sympatric plant species with similar flowering phenologies and floral morphologies may compete for pollination, and as a consequence potentially influence each other\u27s reproductive success and mating system. Two likely competitors are Mimulus ringens and Lobelia siphilitica, which co-occur in wet meadows of central and eastern North America, produce blue zygomorphic flowers, and share several species of bumble bee pollinators. To test for effects of competition for pollination, we planted experimental arrays of Mimulus ringens, each consisting of genets with unique combinations of homozygous marker genotypes. In two arrays we planted mixtures of Mimulus and Lobelia. and in two additional arrays we planted Mimulus without a competitor for pollination. Bumble bee pollinators frequently moved between Mimulus and Lobelia flowers in the mixed-species arrays, with 42% of plant-to-plant movements being interspecific transitions. Pollinator movements between species were associated with a reduction in the amount of conspecific pollen arriving on Mimulus stigmas. The presence of Lobelia led to a significant 37% reduction in the mean number of Mimulus seeds per fruit. In addition, Mimulus had a significantly lower rate of outcrossing in the mixed-species arrays (0.43) than in the pure arrays (0.63). This is the first study to demonstrate that competition for pollination directly influences outcrossing rates. Our work suggests that in self-compatible populations with genetic load, competition for pollination may not only reduce seed quantity, but may also lower seed quality

Western Diet in Adulthood, Timing of Menarche, and Economic Status Among Northeast Ohioans

I studied the age at first menstruation as a predictor of Western diet consumption among adults at The University of Akron and in Cleveland. I used stable carbon and nitrogen isotope compositions of human hair, as well as surveyed consumption of foods important to a Western diet (red meat, sugar, and dairy), to understand whether participants aligned with a Western dietary pattern. Age at survey and adult economic status were investigated as potential confounding variables. My data analysis and conclusions for this project has been completed and approved by my advisor and committee. To maintain collaborators\u27 ability to publish a comprehensive analysis of this dataset, I am not at liberty to publish my results here. Broader analyses of diet composition across lifetime, age at menarche, and economic status represent interesting avenues for future study