Michele R Dudash

University of Maryland, College Park | UMD, UMCP, University of Maryland College Park · Department of Biology

Bats are important pollinators, but they are difficult to study since they are volant and nocturnal. Thus, long-term studies of nectarivorous bats are scarce, despite their potential to help assess trends in bat populations and their pollination services. We used capture rates of nectarivorous bats at chiropterophilous flowers in order to examine t...

An ongoing controversy in invasion biology is the prevalence of colonizing plant populations that are able to establish and spread, while maintaining limited amounts of genetic variation. Invasive populations can be established through several routes including from a single source or from multiple introductions. The aim of this study was to examine...

The onset of spring migratory behavior in birds is thought to be controlled by a rigid endogenous schedule as a result of selection to time migration with environmental conditions on breeding grounds. Recent field studies, however, have revealed flexibility in spring departure schedules and suggest a role for environmental factors such as weather a...

The evolution of floral traits is often considered to reflect selection for increased pollination efficiency. Known as the pollination‐precision hypothesis, increased pollination efficiency is achieved by enhancing pollen deposition on precise areas of the pollinator. Most research to date addressing this hypothesis has examined plant species that...

Identifying environmental correlates driving space-use strategies can be critical for predicting population dynamics; however, such information can be difficult to attain for small mobile species such as migratory songbirds. We combined radio-telemetry and high-resolution GPS tracking to examine space-use strategies under different moisture gradien...

Deciphering how environmental heterogeneity affects population dynamics in migratory species is complicated by the redistribution of individuals in time and space across the annual cycle. Approaches that tackle this problem require information about how migratory species respond to ecological factors across time and space, and how they are linked a...

Conflicting selection is an important evolutionary mechanism since it impedes directional evolution and helps to maintain phenotypic variation. It can arise when mutualistic and antagonistic selective agents exert opposing selection on the same trait and when distinct phenotypic optima are favored by different fitness components. In this study, we...

The first step in conservation management is to delineate groups for separate versus combined management. However, there are many problems with species delineation, including diverse species definitions, lack of standardized protocols, and poor repeatability of delineations. Definitions that are too broad will lead to outbreeding depression if popu...

Adverse genetic impacts on fragmented populations are expected to worsen under global climate change. Many populations and species may not be able to adapt in situ , or to move unassisted to suitable habitat. Management may reduce these threats by augmenting genetic diversity to improve the ability to adapt evolutionarily, by translocation, includi...

Inbreeding is reduced and genetic diversity enhanced when a small isolated inbred population is crossed to another unrelated population. Crossing can have beneficial or harmful effects on fitness, but beneficial effects predominate, and the risks of harmful ones (outbreeding depression) can be predicted and avoided. For crosses with a low risk of o...

Evidence of population structure and limited gene flow often leads to the questionable conclusion that populations should be managed as separate unit. A paradigm shift is needed where evidence of genetic differentiation among populations is followed by an assessment of whether populations are suffering genetic erosion, whether there are other popul...

Genetic management of fragmented populations involves the application of evolutionary genetic theory and knowledge to alleviate problems due to inbreeding and loss of genetic diversity in small population fragments. Populations evolve through the effects of mutation, natural selection, chance (genetic drift), and gene flow. Large outbreeding sexual...

Inbreeding reduces survival and reproduction (i.e. it causes inbreeding depression), and thereby increases extinction risk. Inbreeding depression is due to increased homozygosity for harmful alleles and at loci exhibiting heterozygote advantage. Inbreeding depression is nearly universal in sexually reproducing organisms that are diploid or have hig...

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic di...

Even without detailed genetic data, sound genetic management strategies for augmenting gene flow can be instituted by considering population genetics theory, and/or computer simulations. When detailed data are lacking, moving (translocating) some individuals into isolated inbred population fragments is better than moving none, as long as the risk o...

Humans are responsible for a cataclysm of species extinction that will change the world as we see it, and will adversely affect human health and wellbeing. We need to understand at individual and societal levels why species conservation is important. Accepting the premise that species have value, we need to next consider the mechanisms underlying s...

Background and aims: Population genetic structures and patterns of gene flow of interacting species provide important insights into the spatial scale of their interactions and the potential for local co-adaptation. We analysed the genetic structures of the plant Silene stellata and the nocturnal moth Hadena ectypa. Hadena ectypa acts as one of the...

Thousands of small populations are at increased risk of extinction because genetics and evolutionary biology are not well-integrated into conservation planning – a major lost opportunity for effective actions. We propose that if the risk of outbreeding depression is low, the default should be to evaluate restoration of gene flow to small inbred pop...

Foraging theory predicts that generalist foragers should switch resources more readily, while specialist foragers should remain constant to preferred food resources. Plant-pollinator interactions provide a convenient system to test such predictions because floral resources are often temporally patchy, thus requiring long-lived pollinators to switch...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

One of the greatest unmet issues in conservation biology is the genetic management of fragmented animal and plant populations. Many species across the planet have fragmented distributions with some small isolated populations that are potentially suffering from inbreeding, loss of genetic diversity, and elevated extinction risk. Fortunately, these e...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The biological diversity of the planet is being rapidly depleted due to the direct and indirect consequences of human activity. As the size of animal and plant populations decrease and fragmentation increases, loss of genetic diversity reduces their ability to adapt to changes in the environment, with inbreeding and reduced fitness inevitable conse...

The large majority of angiosperm species depend on animals for pollination, including many agricultural crops, and plant-pollinator interactions have been extensively studied. However, not all floral visitors actually transfer pollen, and efforts to distinguish true pollinators from mere visitors are particularly scarce among the bat pollination li...

Background and aims: Sympatric plant species that share pollinators potentially compete for pollination and risk interspecific pollen transfer, but this competition can be minimized when plant species place pollen on different areas of the pollinator's body. Multiple studies have demonstrated strong differential pollen placement by sympatric plant...

Premise of the study We designed and tested microsatellite markers for the North American native species Silene stellata (Caryophyllaceae) to investigate its population genetic structure and identify selection on floral design through male reproductive success. Methods and Results A total of 153 candidate microsatellite loci were isolated based on...

We document cannibalism in young larvae of Hadena ectypa Morisson, a rare noctuid moth that oviposits in flowers of its host plant Silene stellata L. In 2012 and 2013, we observed high Hadena ectypa adult activity in early flowering season of Silene stellata, when flower density was low. As a result, co-occurrence of related as well as unrelated eg...

Long-distance breeding and natal dispersal play central roles in many ecological and evolutionary processes, including gene flow, population dynamics, range expansion, and individual responses to fluctuating biotic and abiotic conditions. However, the relative contribution of long-distance dispersal to these processes depends on the ability of disp...

Long-distance breeding and natal dispersal play central roles in many ecological and evolutionary processes, including gene flow, population dynamics, range expansion, and individual responses to fluctuating biotic and abiotic conditions. However, the relative contribution of long-distance dispersal to these processes depends on the ability of disp...

Background and aims: Plant species that share pollinators are potentially subject to non-adaptive interspecific pollen transfer, resulting in reduced reproductive success. Mechanisms that increase pollination efficiency between conspecific individuals are therefore highly beneficial. Many nocturnally flowering plant species in Thailand are pollina...

Long-distance breeding and natal dispersal play central roles in many ecological and evolutionary processes, including gene flow, population dynamics, range expansion, and individual responses to fluctuating biotic and abiotic conditions. However, the relative contribution of long-distance dispersal to these processes depends on the ability of disp...

Long-distance dispersal is a fundamental process in ecology and evolution but the factors that influence these movements remain poorly understood in most species. We used stable hydrogen isotopes to quantify the rate and direction of long- distance immigration in a breeding population of American redstarts and to test whether the settlement decisio...

The role of competition in community structure and species interactions is universal. However, how one quantifies the outcome of competitive interactions is frequently debated. Here, we review the strengths and weaknesses of the target-neighbor design, a type of additive design where one of the competing species is reduced to a single individual an...

The processes by which individuals select breeding sites have important consequences for individual tness as well as population‐ and community‐dynamics. Although there is increasing evidence that many animal species use information acquired from conspecics to assess the suitability of potential breeding sites, little is known about how the use of t...

Darwin recognized the flower's importance for the study of adaptation and emphasized that the flower's functionality reflects the coordinated action of multiple traits. Here we use a multi-trait manipulative approach to quantify the potential role of selection acting on floral trait combinations underlying the divergence and maintenance of three re...

Plant–insect interactions often are important for plant reproduction, but the outcome of these interactions may vary with environmental context. Pollinating seed predators have positive and negative effects on host plant reproduction, and the interaction outcome is predicted to vary with density or abundance of the partners. We studied the interact...

Bats are important but understudied pollinators in the Palaeotropics, and much about their interactions with night-blooming, bat-pollinated plant species is still unknown. We compared visitation times to flowering and fruiting plant resources by nectarivorous bat species (obligate pollinators) and frugi-nectarivorous bat species (facultative pollin...

The acquisition of new mutualists and escape from enemies are often essential for the establishment of invasive species. With its introduction to North America, Silene latifolia successfully escaped a number of generalist and specialist enemies, including the seed predator/specialist pollinator Hadena bicruris, but information regarding the acquisi...

Unlabelled: • Premise of the study: Pollinating seed predators are models for the study of mutualisms. These insects have dual effects on host-plant fitness, through pollination as adults and flower and fruit predation as larvae. A rarely examined question is whether pollinating seed-predator oviposition choices are influenced by plant floral an...

The outcome of mutualistic interactions depends on the costs and benefits for each of the partners, which have been shown to be both context‐ and species‐dependent. This phenomenon is seen in the interactions between plants in the genus Silene and moths in the genus Hadena . In this study, the interaction between native North American species Silen...

Background/Question/Methods Many plant species rely on animals for pollination. Consequently, the floral design, reproductive success, and genetic diversity of these plants are influenced by pollinator foraging behavior, which transfers pollen (gametes) between conspecific individuals. Concurrently, host plants offer nectar rewards that influence...

Since the early 1990s, research on genetic variation of phenotypic plasticity has expanded and empirical research has emphasized the role of the environment on the expression of inbreeding depression. An emerging question is how these two evolutionary ecology mechanisms interact in novel environments. Interest in this area has grown with the need t...

Background/Question/Methods Invasive plant species are a major threat to global biodiversity. Invasive plants out-compete native plant species and disrupt native mutualisms, lead to local extinctions, and pose a threat to native plant and animal communities. It has proven very difficult, however, to predict which species will become invasive. The...

Nursery pollination, in which insects use as hosts the very plants they pollinate, ranges from obligate mutualism to parasitism. In the non-obligate interaction between Greya moths and the host Lithophragma sp., the relative density of nursery pollinators and copollinators, which do not use plant tissues for larval development, is a key determinant...

Background/Question/Methods Flowering phenology can influence the outcome of interactions. For pollinating seed predators, flowering and pollinator activity are expected to be synchronous to maximize potential positive interactions. For facultative interactions, some plants may be out of synchrony with their pollinating seed predators, resulting...

Fragmentation of animal and plant populations typically leads to genetic erosion and increased probability of extirpation. Although these effects can usually be reversed by re-establishing gene flow between population fragments, managers sometimes fail to do so due to fears of outbreeding depression (OD). Rapid development of OD is due primarily to...

We tested the utility of fluorescent dye particles as pollen analogs for hummingbird-pollinated Silene virginica (Caryophyllaceae) by comparing the movement of pollen and fluorescent dye across sequentially visited emasculated flowers. We found no differences in either the intercept or the slope of the regressions of the two particle types on flora...

Controversy is ongoing regarding the importance of pollinator-mediated selection as a source of observed patterns of floral diversity. Although increasing evidence exists of pollinator-mediated selection acting on female reproductive success, there is still limited understanding of pollinator-mediated selection on floral traits via male reproductiv...

Background/Question/Methods Invasive plant species are a major threat to biodiversity. They out-compete native plant species and disrupt native mutualisms, leading to local extinctions and posing a threat to endangered plants and animals. Predicting which species will become invasive, however, has proven to be difficult. The role of plant phenolog...

Background/Question/Methods Within plant populations, species interactions may affect population establishment and persistence. Nursery pollination is a unique plant-insect interaction in which flowers are used as brood sites for the pollinator’s developing young, and in some nursery pollination systems, non-seed predator copollinators may be pres...

Pollination syndromes suggest that convergent evolution of floral traits and trait combinations reflects similar selection pressures. Accordingly, a pattern of selection on floral traits is expected to be consistent with increasing the attraction and pollen transfer of the important pollinator. We measured individual variation in six floral traits...

Community and biogeographic surveys often conclude that plant-pollinator interactions are highly generalized. Thus, a central implication of the pollination syndrome concept, that floral trait evolution occurs primarily via specialized interactions of plants with their pollinators, has been questioned. However, broad surveys may not distinguish whe...

To better understand invasion dynamics, it is essential to determine the influence of genetics and ecology in species persistence in both native and nonnative habitats. One approach is to assess patterns of selection on floral and growth traits of individuals in both habitats. Mimulus guttatus (Phrymaceae) has a mixed mating system and grows under...

The number of ovules per flower varies over several orders of magnitude among angiosperms. Here we consider evidence that stochastic uncertainty in pollen receipt and ovule fertilization has been a selective factor in the evolution of ovule number per flower. We hypothesize that stochastic variation in floral mating success creates an advantage to...

We tested for an association between nectar and various floral traits and investigated their roles as primary and secondary pollinator attractants in hummingbird-pollinated Silene virginica. Our goal was to gain insight into the mechanisms of pollinator-mediated selection that underlies floral trait divergence within the genus. In a field populatio...

Low Ca/Mg ratios (a defining component of serpentine soils) and low water environmental conditions often co-occur in nature and are thought to exert strong selection pressures on natural populations. However, few studies test the individual and combined effects of these environmental factors. We investigated the effects of low Ca/Mg ratio and low w...

Nursery pollinators, and the plants they use as hosts for offspring development, function as exemplary models of coevolutionary mutualism. The two pre-eminent examples--fig wasps and yucca moths--show little variation in the interaction: the primary pollinator is an obligate mutualist. By contrast, nursery pollination of certain Caryophyllaceae, in...

Quantifying the extent to which seed production is limited by the avail-ability of pollen has been an area of intensive empirical study over the past few decades. Whereas theory predicts that pollen augmentation should not increase seed production, numerous empirical studies report significant and strong pollen limitation. Here, we use a variety of...

In the preservation of plant biodiversity, there are fundamental genetic and ecological similarities involved in: (1) predicting the fate of small, isolated populations, (2) ensuring the successful reintroduction of endangered species back into natural habitats, and (3) understanding the establishment of species beyond their native ranges. In all t...

Floral evolution has often been associated with differences in pollina-tion syndromes. Recently, this conceptual structure has been criticized on the grounds that flowers attract a broader spectrum of visitors than one might expect based on their syndromes and that flowers often diverge without excluding one type of pollinator in favor of another....

Determining whether seed production is pollen limited has been an area of intensive empirical study over the last two decades. Yet current evidence does not allow satisfactory assessment of the causes or consequences of pollen limitation. Here, we critically evaluate existing theory and issues concerning pollen limitation. Our main conclusion is th...

Predictions for the evolution of mating systems and genetic load vary, depending on the genetic basis of inbreeding depression (dominance versus overdominance, epistasis and the relative frequencies of genes of large and small effect). A distinction between the dominance and overdominance hypotheses is that deleterious recessive mutations should be...