Nicole E. Miller-Struttmann

• PhD
• Associate Professor and Laurence L. Browning Jr. Endowed Chair at Webster University

Changes to flowering phenology are a key response of plants to climate change. However, we know little about how these changes alter temporal patterns of reproductive overlap (i.e. phenological reassembly). We combined long‐term field (1937–2012) and herbarium records (1850–2017) of 68 species in a flowering plant community in central North America...

Engaging students in research is increasingly recognized as a valuable pedagogical tool that can augment student learning outcomes. Here, we present an original activity that utilizes research as pedagogy to teach upper-division college students about phenological responses to climate change. By studying phenological responses in multiple species,...

Pollinators at high elevations face multiple threats from climate change including heat stress, failure to phenological match advancing flower resources and competitive pressure from range‐expanding species of lower elevations. We conducted long‐term multi‐site surveys of alpine bumble bees to determine how phenology of range‐stable and range‐expan...

Over the last six decades, populations of the bumblebees Bombus sylvicola and Bombus balteatus in Colorado have experienced decreases in tongue length, a trait important for plant‐pollinator mutualisms. It has been hypothesized that this observation reflects selection resulting from shifts in floral composition under climate change. Here we used mo...

Evidence is accumulating that gene flow commonly occurs between recently-diverged species, despite the existence of barriers to gene flow in their genomes. However, we still know little about what regions of the genome become barriers to gene flow and how such barriers form. Here we compare genetic differentiation across the genomes of bumblebee sp...

Populations of the bumblebees Bombus sylvicola and Bombus balteatus in Colorado have experienced decreases in tongue length, a trait important for plant-pollinator mutualisms, in the last six decades. It is hypothesized that this reflects selection exerted by changes in floral composition under climate change. Here we combine extensive morphometric...

Under climate change, shrubs encroaching into high altitude plant communities disrupt ecosystem processes. Yet effects of encroachment on pollination mutualisms are poorly understood. Here, we probe potential fitness impacts of interference from encroaching Salix (willows) on pollination quality of the alpine skypilot, Polemonium viscosum. Overlap...

Multiple interacting factors drive recent declines in wild and managed bees, threatening their pollination services. Widespread and intensive monitoring could lead to more effective management of wild and managed bees. However, tracking their dynamic populations is costly. We tested the effectiveness of an inexpensive, noninvasive and passive acous...

Acoustic monitoring may improve farmer and biologist response times to pollinator population deficits. Acoustic signals reflect pollinator abundance and functional traits that predict pollination services. Leveraging these signals, pollinator deficits can be identified quickly, allowing farmers to supplement wild pollinators with domesticated bee c...

References for characteristic frequency of flight buzzes and tongue length measurements collated from the literature. The mean weighted by sample size was calculated for any species and caste with more than value for characteristic frequency or tongue length. (DOCX)

In a recent paper, we reported on the evolution of shorter tongues in two alpine bumble bee species in response to climate-induced flower deficits. De Keyzer et al. concede that tongue lengths have decreased but criticize the level of support for our claims. Here, we address the alternative mechanisms they proposed, highlight evidence presented in...

Restoration of glades over the past 30 years, involving removal of woody cover and re-establishment of herbaceous plant communities, has created an archipelago of habitat patches varying in age, size, and isolation. Within these glades, habitat varies in quality from edge to core. We investigated impacts of within- and among-glade variation on the...

Climate change decoupling mutualism Many coevolved species have precisely matched traits. For example, long-tongued bumblebees are well adapted for obtaining nectar from flowers with long petal tubes. Working at high altitude in Colorado, Miller-Struttmann et al. found that long-tongued bumblebees have decreased in number significantly over the pas...

We use an extensive historical data set on bumble bee host choice collected almost 50 years ago by L. W. Macior (Melanderia 15:1-59, 1974) to examine how resource partitioning by bumble bees varies over a 2,700-m altitudinal gradient at four hierarchical scales: individual, colony, species and community. Bumble bee behavior, resource overlap betwee...

Background/Question/Methods As species respond to climate change, the composition of mutualistic partners in communities is shifting. By altering the distribution of important interaction traits in one trophic level, changes in community structure may influence the evolution of traits in another. Plant-pollinator interactions are mediated by poll...

Similar to aboveground herbivores, root-feeding insects must locate and identify suitable resources. In the darkness of soil, they mainly rely on root chemical exudations and, therefore, have evolved specific behaviours. Because of their impact on crop yield, most of our knowledge in belowground chemical ecology is biased towards soil-dwelling inse...

Understanding how species with historically fragmented populations are able to persist will provide insights into which factors may be important for the maintenance of newly fragmented populations. Plants with fragmented and isolated populations, such as habitat-specialist (HS) species, are likely less attractive to pollinators and may have adaptiv...

Background/Question/Methods There is evidence from a diversity of biomes that plants and animals are responding to climate change independently; however, few studies have explored how changes in the distributions, phenology, and morphological traits of one partner will affect its encounters with and dependence upon the other. In alpine ecosystems...

Background/Question/Methods At the close of our MU GK-12 summer teacher-fellow ‘boot-camp’, one teacher, in commenting on her fellow-mentored research experience said, “It reminded me, a teacher, of how learning feels”. Bringing together master teachers and scientists with a passion for research is the catalysis for learning in all GK-12 programs....

Background/Question/Methods The traditional stress-competition tradeoff in niche theory states that traits adaptive for high stress environments are maladaptive when competition for shared resources is high. Historically, this tradeoff has been conceptualized as competition for abiotic resources, but biotic interactions, such as competition for po...

Background/Question/Methods With the increased prevalence and scale of anthropogenic influences on native habitats, many species, particularly rare and endemic species, are at risk of extinction. Understanding species responses to regional climatic change is imperative for conservation purposes. In response to xeric environments, plants often have...

Background/Question/Methods Variation in the distributions of species has intrigued scientists for centuries. One mechanism that may play a significant role is a trade-off between competition and adaptation to stressful, abiotic conditions. In response to xeric environments, plants often have similar suites of traits that are thought to be adaptive...

Obesity is associated with cognitive impairments. Long-term mechanisms for this association include consequences of hyperglycemia, dyslipidemia, or other factors comprising metabolic syndrome X. We found that hypertriglyceridemia, the main dyslipidemia of metabolic syndrome X, is in part responsible for the leptin resistance seen in obesity. Here w...

Fine-root production and turnover are important regulators of the biogeochemical cycles of ecosystems and key components of their response to global change. We present a nearly continuous 6-year record of fine-root production and mortality from minirhizotron analysis of a closed-canopy, deciduous sweetgum forest in a free-air CO(2) enrichment exper...

This dissertation documents the relationship between stress-adaptation and reproductive specialization in three endemic plant species (Delphinium treleasei, Echinacea paradoxa, and Scutellaria bushii) that are locally abundant but restricted to stressful habitats and their closely-related congeners (D. carolinianum, E. pallida, S. ovata, and S. par...