Biology subjects

Meineke, E. K.

Publications and source records attributed to Meineke, E. K..

6 recordsLinked to original sources

bioRxiv2026

Supplemental water modulates pollinator visitation on resource-rich plant species

Urban green spaces provide important floral resources for pollinators, and supplemental watering can improve the abundance and quality of these resources. However, increasing frequency and intensity of drought under climate change create tradeoffs between ecological benefits and water conservation. Manipulating the timing and duration of irrigation may offer a way of enhancing floral traits that support pollinator communities while moderating water use. Focusing on two resource-rich native plant species, Phacelia californica and Helenium puberulum, we examined how the addition of supplemental water in spring and summer affects floral traits and pollinator visitation. We examined mechanisms that may govern the effects of supplemental watering on pollinator visitation, namely the number of flowers, nectar volume, nectar sucrose concentration, and corolla length. Overall, plant individuals receiving more water were visited by more pollinators. In both plant species, this was apparently mediated by floral abundance; individual plants with more flowers received more visitors, though effects of watering varied slightly between the two plant species and the insect visitor taxa. Water additions in spring increased pollinator visitation per plant on P. californica, but visitation rates per flower did not differ among treatments. Responses among pollinator groups varied, with effects driven primarily by sweat bees (family: Halictidae) and bumble bees (Bombus species), while honeybee visitation was consistent across treatments. Our results suggest that insects prefer to visit supplementally watered P. californica plants. Because honeybee visitation did not vary by treatment, supplemental water may disproportionately benefit native pollinators, including bumblebees, which are imperiled. Similar to P. californica, Helenium puberulum plants watered in spring and summer had the most flowers and the most floral visitors per plant and per flower. Spring-watering H. puberulum did not have a significant effect on flower production but did increase insect visitation per flower. Overall, our results emphasize that irrigation and other avenues of water addition are key drivers of flower production and insect visitation, such that homeowners who wish to conserve water must weigh effects on pollinators with the need to conserve water in arid climates.

ecology↗

bioRxiv2022

Vehicle pollution is associated with elevated insect damage to street trees

O_LIVehicle pollution is a pervasive aspect of anthropogenic change across rural and urban habitats. The most common emissions are carbon- or nitrogen-based pollutants that may impact diverse interactions between plants and insect herbivores. However, the effects of vehicle pollution on plant-insect interactions are poorly understood. C_LIO_LIHere, we combine a city-wide experiment across the Sacramento Metropolitan Area and a laboratory experiment to determine how vehicle emissions affect insect herbivory and leaf nutritional quality. C_LIO_LIWe demonstrate that leaf damage to a native oak species (Quercus lobata) commonly planted across the western US is substantially elevated on trees exposed to vehicle emissions. In the laboratory, caterpillars preferred leaves from highway-adjacent trees and performed better on leaves from those same trees. C_LIO_LISynthesis and applications. Together, our studies demonstrate that the heterogeneity in vehicle emissions across cities may explain highly variable patterns of insect herbivory on street trees. Our results also indicate that trees next to highways are particularly vulnerable to multiple stressors, including insect damage. To combat these effects, urban foresters may consider installing trees that are less susceptible to insect herbivory along heavily traveled roadways. C_LI

ecology↗

bioRxiv2019

Applying Machine Learning to Investigate Long Term Insect-Plant Interactions Preserved on Digitized Herbarium Specimens

Premise of the studyDespite the economic importance of insect damage to plants, long-term data documenting changes in insect damage ( herbivory) and diversity are limited. Millions of pressed plant specimens are now available online for collecting big data on plant-insect interactions during the Anthropocene.\n\nMethodsWe initiated development of machine learning methods to automate extraction of herbivory data from herbarium specimens. We trained an insect damage detector and a damage type classifier on two distantly related plant species. We experimented with 1) classifying six types of herbivory and two control categories of undamaged leaf, and 2) detecting two of these damage categories for which several hundred annotations were available.\n\nResultsClassification models identified the correct type of herbivory 81.5% of the time. The damage classifier was accurate for categories with at least one hundred test samples. We show anecdotally that the detector works well when asked to detect two types of damage.\n\nDiscussionThe classifier and detector together are a promising first step for the automation of herbivory data collection. We describe ongoing efforts to increase the accuracy of these models to allow other researchers to extract similar data and apply them to address a variety of biological hypotheses.

ecology↗

bioRxiv2019

Temperature accounts for the biodiversity of a hyperdiverse group of insects in urban Los Angeles

The urban heat island effect is a worldwide phenomenon that has been linked to species distributions and abundances in cities. However, effects of urban heat on biotic communities are nearly impossible to disentangle from effects of land cover in most cases because hotter urban sites also have less vegetation and more impervious surfaces than cooler sites within cities. We sampled phorid flies, one of the largest, most biologically diverse families of true flies (Insecta: Diptera: Phoridae), at 30 sites distributed within the central Los Angeles Basin, where we found that temperature and the density of urban land cover are decoupled. Abundance, richness, and community composition of phorids inside urban Los Angeles were most parsimoniously accounted for by mean air temperature in the week preceding sampling. Sites with intermediate mean temperatures had more phorid fly individuals and higher richness. Communities were more even at urban sites with lower minimum temperatures and sites located further away from natural areas, suggesting that communities separated from natural source populations may be more homogenized. Species composition was best explained by minimum temperature. Inasmuch as warmer areas within cities can predict future effects of climate change, phorid fly communities are likely to shift non-linearly under future climates in more natural areas. Exhaustive surveys of biotic communities within cities, such as the one we describe here, can provide baselines for determining the effects of urban and global climate warming as they intensify.

ecology↗

bioRxiv2018

Herbarium records reveal early flowering in response to warming in the southern hemisphere

Premise of the StudyHerbarium specimens are increasingly used as records of plant flowering phenology, which has advanced for many species in response to climate change. However, most herbarium-based studies on plant phenology focus on taxa from temperate parts of the northern hemisphere. Here, we explore flowering phenologic responses to climate in a temperate/subtropical plant genus Protea (Proteaceae), an iconic group of woody plants with year-round flowering phenology and endemic to sub-Saharan Africa. Protea is widely used in horticulture and is a flagship genus for the flora of the hyperdiverse Cape Floristic Region.\n\nMethodsWe used a database of 2154 herbarium records of 25 Protea species to explore patterns in flowering spanning the past 100 years. We used a circular sliding window analysis to characterize phenological patterns in these aseasonal species, plus a novel linear mixed effects model formulation to test how both site-to-site and year-to-year variation in temperature and precipitation affect flowering date across species.\n\nResultsBoth warmer sites and warmer years were associated with earlier flowering of 3-5 days/{degrees}C. In general, the timing of peak flowering was influenced more strongly by temperature than precipitation. Although species vary widely in when they flower during the year, their phenological responses to temperature are phylogenetically conserved, with closely related species tending to shift flowering time similarly with increasing temperature.\n\nDiscussionTogether, our results point to climate-responsive phenology for this important plant genus. Our results indicate that the subtropical, aseasonally-flowering genus Protea has temperature-driven flowering phenologic responses that are remarkably similar in magnitude to those of better-studied northern temperate plant species, suggesting a generality across biomes that has not been described elsewhere.

ecology↗

bioRxiv2017

The unrealized potential of herbaria in global change biology

Plant and fungal specimens in herbaria are becoming primary resources for investigating how plant phenology and geographic distributions shift with climate change, greatly expanding inferences across spatial, temporal, and phylogenetic dimensions. However, these specimens contain a wealth of additional data--including nutrients, defensive compounds, herbivore damage, disease lesions, and signatures of physiological processes--that capture ecological and evolutionary responses to the Anthropocene but which are less frequently utilized. Here, we outline the diversity of herbarium data, global change topics to which they have been applied, and new hypotheses they could inform. We find that herbarium data have been used extensively to study impacts of climate change and invasive species, but that such data are less commonly used to address other drivers of biodiversity loss, including habitat conversion, pollution, and overexploitation. In addition, we note that fungal specimens are under-explored relative to vascular plants. To facilitate broader application of plant and fungal specimens in global change research, we outline the limitations of these data and modern sampling and statistical tools that may be applied to surmount challenges they present. Using a case study of insect herbivory, we illustrate how novel herbarium data may be employed to test hypotheses for which few data exist, despite potentially large biases. With the goal of positioning herbaria as hubs for global change research, we suggest future research directions and curation priorities.

plant biology↗