Elsa Youngsteadt

Sigma Xi, The Scientific Research Honor Society

Most canopy insect research takes place in tropical forests, where communities are highly vertically stratified. However, temperate forest canopies also provide critical resources to many species and are under intense pressure from global change drivers. The relative lack of knowledge regarding temperate canopy insect ecology impedes our forest man...

Mutualistic interactions between species underpin biodiversity and ecosystem function, but may be lost when partners respond differently to abiotic conditions. Except for a few prominent examples, effects of global anthropogenic change on mutualisms are poorly understood. Here we assess the effects of urbanization on a symbiosis in which the plant...

Premise Understanding the factors that limit reproductive success is a key component of plant biology. Carnivorous plants rely on insects as both nutrient sources and pollinators, providing a unique system for studying the effects of both resource and pollen limitation on plant reproduction. Methods We conducted a field experiment using wild‐growi...

Compared to non-urban environments, cities host ecological communities with altered taxonomic diversity and functional trait composition. However, we know little about how these urban changes take shape over time. Using historical bee (Apoidea: Anthophila) museum specimens supplemented with online repositories and researcher collections, we investi...

Aphaenogaster mariae Forel is a rarely encountered North American arboreal ant that has eluded collectors for decades. Here, we provide the first formal documentation of a whole colony collection of the species found seventeen meters high in the canopy of the North Carolina Piedmont. We discovered a mature colony with more than 1000 individuals, in...

Pollination is an essential component of plant reproduction that is transformed by the novel environmental conditions in cities. We summarize patterns of urban plant reproduction and trace the mechanisms by which urban environments influence pollination, beginning at the level of the individual plant. We then progress through several processes uniq...

Global declines in bumblebee populations are linked to climate change, but specific mechanisms imposing thermal stress on these species are poorly known. Here we examine the potential for heat stress in workers foraging for pollen, an essential resource for colony development. Laboratory studies have shown that pollen foraging causes increased thor...

Purpose of Review Global urban land area is growing faster than the urban population, raising concerns that sprawling, low-density development will reduce biodiversity and human wellbeing. The sparing-sharing framework, adapted from agroecology, provides one approach to assessing alternative urban growth patterns. It compares ecological outcomes in...

Global climate change is expected to have pervasive effects on the diversity and distribution of species, particularly ectotherms whose body temperatures depend on environmental temperatures. However, these impacts remain difficult to predict, in part because ectotherms may adapt or acclimate to novel conditions or may use behavioural thermoregulat...

Wild bees can be essential pollinators in natural, agricultural, and urban systems, but populations of some species have declined. Efforts to assess the status of wild bees are hindered by uncertainty in common sampling methods, such as pan traps and aerial netting, which may or may not provide a valid index of abundance across species and habitats...

Prescribed burning is a common silvicultural practice used in the management of longleaf pine (Pinus palustris Mill., Pinales: Pinaceae) savannas to reduce hardwood encroachment and ground cover and to maintain biodiversity. We investigated the response of the native bee community (Hymenoptera: Apoidea: Anthophila) in the Sandhills of North Carolin...

Dioecy is rare among flowering plants, and is associated with a high frequency of threatened species. Dioecious plants are often pollinated by wind or insects, but are susceptible to pollination failure should male and female plants become spatially separated, or should pollinator abundance decline. Here we characterize the plant–pollinator interac...

Management of natural habitats is an important strategy for rare plant conservation. One common tool for managing natural habitats is the use of controlled fire. Rare plants in fire-dependent ecosystems often rely on frequent fires to increase nutrient availability, initiate germination, and limit cover from light competitors. Fire can also alter a...

Low cost temperature sensors are increasingly used by ecologists to assess climatic variation and change on ecologically relevant scales. Although cost-effective, if not deployed with proper solar radiation shielding, the observations recorded from these sensors will be biased and inaccurate. Manufactured radiation shields are effective at minimizi...

As cities expand, conservation of beneficial insects is essential to maintaining robust urban ecosystem services such as pollination. Urban warming alters insect physiology, fitness, and abundance, but the effect of urban warming on pollinator communities has not been investigated. We sampled bees at 18 sites encompassing an urban warming mosaic wi...

Linked Article: https://doi.org/10.1002/ece3.3965

Because carnivorous plants rely on arthropods as pollinators and prey, they risk consuming would-be mutualists. We examined this potential conflict in the Venus flytrap (Dionaea muscipula), whose pollinators were previously unknown. Diverse arthropods from two classes and nine orders visited flowers; 56% of visitors carried D. muscipula pollen, oft...

A foundation of integrated pest management (IPM) in urban landscapes is to put the right plant in the right place. This preventive tactic can reduce plant stress, pest infestations, and subsequent pesticide applications. Many urban tree species have more insect and mite pests in urban landscapes than in surrounding natural areas. This is due in par...

The frequency and intensity of hurricanes are increasing globally, and anthropogenic modifications in cities have created systems that may be particularly vulnerable to their negative effects. Organisms living in cities are exposed to variable levels of chronic environmental stress. However, whether chronic stress ameliorates or exacerbates the neg...

In light of global climate change, ecological studies increasingly address effects of temperature on organisms and ecosystems. To measure air temperature at biologically relevant scales in the field, ecologists often use small, portable temperature sensors. Sensors must be shielded from solar radiation to provide accurate temperature measurements,...

Changes in community composition are an important, but hard to predict, effect of climate change. Here,we use a wild-bee study system to test the ability of critical thermal maxima (CTmax, a measure of heat tolerance) to predict community responses to urban heat-island effects in Raleigh, NC, USA. Among 15 focal species, CTmax ranged from 44.6 to 5...

Honey bees are the most important managed pollinators as they provide key ecosystem services for crop production worldwide. Recent losses of honey bee colonies in North America and Europe have demonstrated a need to develop strategies to improve their health and conserve their populations. Previously, we showed that feral honey bees—colonies that l...

Biological effects of climate change are expected to vary geographically, with a strong signature of latitude. For ectothermic animals, there is systematic latitudinal variation in the relationship between climate and thermal performance curves, which describe the relationship between temperature and an organism's fitness. Here we ask whether these...

A substantial amount of global carbon is stored in mature trees. However, no experiments to date test how warming affects mature tree carbon storage. Using a unique, citywide, factorial experiment, we investigated how warming and insect herbivory affected physiological function and carbon sequestration (carbon stored per year) of mature trees. Urba...

“ Each species must be known by one name only, throughout the entire extent of its range. This systematic study is the foundation upon which all the other work of seemingly more practical importance is based ” [T. B. Mitchell (1946)][1] [1]: #ref-10

Trees provide ecosystem services that benefit humans and the environment. Unfortunately, urban trees often do not provide maximum services due to abiotic stress and arthropod herbivores and borers. These problems often originate from trees being planted in unsuitable conditions. Cities are warmer than natural areas because impervious surfaces absor...

Timeline of response variable measurements. This shows when treatments were implemented and insect and tree growth and photosynthesis data were collected.

Timeline of response variable measurements. This shows when treatments were implemented and insect and tree growth and photosynthesis data were collected.

Detailed statistics. Relevant statistical information not included in the main manuscript is included here. In all mixed effects models, "Site" was specified as the random effect. In GLMER, sample ID was also included as a random effect

Detailed statistics. Relevant statistical information not included in the main manuscript is included here. In all mixed effects models, "Site" was specified as the random effect. In GLMER, sample ID was also included as a random effect

Given the role of infectious disease in global pollinator decline, there is a need to understand factors that shape pathogen susceptibility and transmission in bees. Here we ask how urbanization affects the immune response and pathogen load of feral and managed colonies of honey bees (Apis mellifera Linnaeus), the predominant economically important...

The biological diversity and composition of microorganisms influences both human health outcomes and ecological processes; therefore, understanding the factors that influence microbial biodiversity is key to creating healthy, functional landscapes in which to live. In general, biological diversity is predicted to be limited by habitat size, which f...

Urban green spaces provide ecosystem services to city residents, but their management is hindered by a poor understanding of their ecology. We examined a novel ecosystem service relevant to urban public health and esthetics: the consumption of littered food waste by arthropods. Theory and data from natural systems suggest that the magnitude and res...

Global urbanisation is rapidly expanding and most of the world's humans now live in cities. Most ecological studies have, however, focused on protected areas. To address this issue, we tested predictions from studies of protected areas in urban ecosystems. Because most cities are heterogeneous habitat mosaics which include habitats with varying lev...

Cities experience elevated temperature, CO 2 , and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long-term observations. Here, we examine the response of an herbivore, the...

Background/Question/Methods: The frequency and intensity of extreme weather events are increasing globally, while urbanization is rapidly expanding worldwide. However, we have a poor understanding of how these simultaneous global changes interact to influence local community dynamics and ecosystem services. Home to more than half of the world’s hum...

Background/Question/Methods All organisms produce, detect, and respond to chemical cues, and chemistry is often a critical mediator of plant-animal interactions. Humans are less attuned to such signals than are many other organisms, and chemical ecologists sometimes struggle to communicate the nature of the invisible processes they study. Using e...

Texas gourd vines unfurl their large, flared blossoms in the dim hours before sunrise. Until they close at noon, their yellow petals and mild, squashy aroma attract bees that gather nectar and shuttle pollen from flower to flower. The researchers also wanted to know whether extra beetles would impose a double cost by both damaging flowers and deter...

Suicide is an evolutionary conundrum with single-celled organisms regularly killing themselves in reaction to stresses they might have survived. In multi-cellular organisms, programmed cell death (PCD) demands no special explanation because it is not really suicide. Although premature death has turned out to be common in single-celled organisms, bi...

Composition of blends mentioned in Table S1. (PDF)

Results of exploratory seed-carrying assays with sugars and with combinations of sugars, amino acids and volatile compounds. (PDF)

Ant response to (a) dilute A. gracile extract (0.1 seed-equivalent per test seed) alone or with the addition of glucose (G) and fructose (F), sucrose (S) or a combination of the three. Addition of sugars did not enhance ant preference for test seeds. Because sugars were presented by weight rather than by their respective molarity, non -preference f...

Results of ANOVA on ranks, testing for effects of treatment (dilute A. gracile extract alone or with the addition of glucose and fructose, sucrose or a combination of the three, matched for weight of sugar per seed) on the order in which ants retrieved test seeds. (PDF)

Results of ANOVA on ranks, testing for effects of treatment (dilute A. gracile extract alone or with the addition of glucose and fructose or sucrose, matched for moles of sugar per seed) on the order in which ants retrieved test seeds. (PDF)

Results of exploratory seed-carrying assays with volatile compounds, presented individually and in blends. (PDF)

In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs). In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants a...

Camponotus femoratus is an abundant and behaviorally dominant ant in lowland Amazonian rainforests, where this species participates in a complex and obligate seed-dispersal mutualism. C. femoratus typically cohabits with another ant species Crematogaster levior in an apparently amiable but poorly understood interaction. Despite these outstanding ch...

Throughout Amazonia, the ant Crematogaster levior is known for its participation in a complex ant-garden mutualism with the ant Camponotus femoratus and several species of epiphytic plants for which it plays an important role in seed viability. We isolated nine polymorphic microsatellite loci for C. levior from a genomic library enriched for di-, t...

Throughout lowland Amazonia, arboreal ants collect seeds of specific plants and cultivate them in nutrient-rich nests, forming diverse yet obligate and species-specific symbioses called Neotropical ant-gardens (AGs). The ants depend on their symbiotic plants for nest stability, and the plants depend on AGs for substrate and nutrients. Although the...

Classic genetic model organisms--fruit flies, zebrafish, and roundworms--are popular newcomers in sleep research laboratories, although debate continues about how much their dozing relates to human slumber.

VIROLOGYA study out this week suggests that in addition to predisposing carriers to Alzheimer's disease, the defective lipid transporter apolipoprotein E4 also hastens the death of people infected with HIV, possibly by allowing the virus easy entry into cells.

Researchers have discovered an environmental hiding place for the bacteria that cause a devastating disease known as Buruli ulcer. The accomplishment marks a major milestone in efforts to understand and control one of the world's most neglected tropical diseases.

Seed dispersal mutualisms are essential for the survival of diverse plant species and communities worldwide. Among invertebrates, only ants have a major role in seed dispersal, and thousands of plant species produce seeds specialized for ant dispersal in “diffuse” multispecies interactions. An outstanding but poorly understood ant–seed mutualism oc...

Tuberculosis bacteria can evolve resistance to antibiotics and still be just as aggressive as their susceptible ancestors. The evolutionary changes that lead to drug resistance occur differently in human patients and culture dishes. Bacteria exist in heterogeneous populations of different strains. The drug-resistant mutations that aren't costly are...

Butterfly caterpillars in the lycaenid subfamily Miletinae are predators of ant-tended Homoptera, yet they lack specialized secretory and call-production organs crucial to ant association in other lycaenids. Here, we address the question of how miletine caterpillars have invaded the ant-Homoptera symbiosis through a study of the only New World mile...

Embryos of the viviparous cockroach Diploptera punctata accumulate large amounts of hydrocarbon (HC) of either maternal or embryonic origin. HC synthesis and its accumulation in maternal and embryonic tissues were measured over the course of gestation. Female abdominal integument was the only tissue that synthesized appreciable amounts of HC in vit...

Neotropical ant-gardens: Behavioral and chemical ecology of an obligate ant-plant mutualism