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Several species of bumblebees have recently experienced range contractions and possible extinctions. While threats to bees are numerous, few analyses have attempted to understand the relative importance of multiple stressors. Such analyses are critical for prioritizing conservation strategies. Here, we describe a landscape analysis of factors predicted to cause bumblebee declines in the USA. We quantified 24 habitat, land-use and pesticide usage variables across 284 sampling locations, assessing which variables predicted pathogen prevalence and range contractions via machine learning model selection techniques. We found that greater usage of the fungicide chlorothalonil was the best predictor of pathogen (Nosema bombi) prevalence in four declining species of bumblebees. Nosema bombi has previously been found in greater prevalence in some declining US bumblebee species compared to stable species. Greater usage of total fungicides was the strongest predictor of range contractions in declining species, with bumblebees in the northern USA experiencing greater likelihood of loss from previously occupied areas. These results extend several recent laboratory and semi-field studies that have found surprising links between fungicide exposure and bee health. Specifically, our data suggest landscape-scale connections between fungicide usage, pathogen prevalence and declines of threatened and endangered bumblebees.

Coral reefs are ecologically and economically important, contributing to both fishing and ecotourism economies around the world. Tourism and recreational activities have increased in coastal areas and so has the use of sunscreen. Sunscreen reduces human exposure to harmful UV rays, but washes off during aquatic recreational activities, which may negatively affect reef biota. To evaluate how sunscreen affects coral reef ecosystems, we added sunscreen at concentrations similar to previous studies to growing environments containing flatworms (Convolutriloba macropyga) with symbiotic algae, photosynthetic diatoms (Nitzschia sp.), Aiptasia anemones, and pulse corals (Xenia sp.). Using behavioral observations and estimates of population and colony growth, we show nominal concentrations of sunscreen negatively affect all of the studied species. Furthermore, we show that mobile flatworms do not avoid water which contains sunscreen and flatworms exposed to sunscreen prefer darker conditions. Based on our results, beach goers should limit use of sunscreens when near coral reefs and consider alternative protective measures, such as the utilization of sun-protective clothing.

Land conversion for human use poses one of the greatest threats to terrestrial ecosystems and causes habitat loss for a myriad of species. The development of large solar energy facilities and urban sprawl are converting wild lands in the Southwest deserts of the USA for human use and resulting in habitat loss for desert species. This is in part due to the Southwest deserts being identified as having high renewable energy potential while urban areas expand into areas supporting high biodiversity. Previous studies have quantified development within some of these biodiversity hotspots, but none have investigated direct species-specific habitat loss for different species of pollinators. Native bees are poorly studied, and therefore it is difficult to know how much habitat has been lost. We quantified the amount of land conversion occurring between 2010 and 2015 in Clark County, NV, Mojave County, AZ, and San Bernardino County, CA to assess direct loss of potential-habitat for species in the Southwest deserts. Using Satellite images, we quantified the direct habitat loss to solar facilities and estimated other land conversion due to urban sprawl using USDA land cover data. We created eco-niche models in MaxENT for ten Ashmeadiella bees, to estimate the amount of direct, potential-habitat loss caused by solar development and urban expansion. Our data suggest species are not equally affected by land conversion in the Southwest deserts and direct, potential-habitat loss to urban sprawl is much greater than the loss due to solar facilities. Furthermore, our data show each species incurs different amounts of habitat loss to both solar development and urban expansion as well as between counties. These results should assist in pollinator conservation program development by illustrating land conversion can vary between local governments and pollinator species.

In the past decade, caverniculous bat populations have plummeted due to White-nose syndrome (WNS). Tri-colored bat ( Perimyotis subflavus ) populations have declined drastically in areas where WNS has been found, leading to the decision to protect tri-colored bats under the federal Endangered Species Act in the United States. At this time, there has not been a thorough review of the literature, nor a concise summary of the tri-colored bat’s life history, diet, threats, or habitat preferences. This absence creates more work for policy makers, federal “Take” permit applicants, and conservationists to find, access, and review critical details of tri-colored bats. A major point of confusion stems from the multiple common names and genera tri-colored bats have been classified under since it was first described a century and a half ago. To address the lack of concise summary, we scoured the scientific literature and compiled nearly a century of data to provide a robust review of the ecology, life history, winter and summer habitats, as well as created maps and figures showing counties where studies have occurred, white-nose syndrome is present, and where bats have been documented. Additionally, this paper highlights data gaps and suggests future research topics that may better inform conservation and management decisions for tri-colored bats.

Prey populations can be strongly influenced by predators and parasitoids, and migratory prey whose distributions vary geographically throughout their breeding seasons encounter different combinations of predators and parasitoids throughout their range. North American monarch butterflies (Danaus plexippus) are susceptible to a wide variety of natural enemies, but the distribution of these natural enemies has not been quantified. We developed ecological niche models using environmental data to identify areas with suitable abiotic conditions for eight known natural enemies of monarchs, including six predators: Arilus cristatus, Harmonia axyridis, Monomorium minimum, Podisus maculiventris, Polistes spp., and Solenopsis geminata; and two parasitoids: Lespesia archippivora and Pteromalus cassotis. We combined correlated suitable areas for individual predators and parasitoids to identify regions with the most predator and parasitoid species potential. The Gulf Coast, West Coast, Florida, and parts of the eastern United States are predicted to have the most natural enemy species. We suggest that future research should assess monarch mortality rates in these areas, and that monarch conservation strategies consider pressure from natural enemies.

Light affects all aspects of plant growth and development from seed germination to senescence. While there has been intensive investigation of the effects of blue and red light on development and tropisms, much less is known about the specific effects of green light exposure in plants. Several recent studies demonstrate that monochromatic green light has a number of physiological effects including antagonizing light-mediated growth inhibition in hypocotyls and reversing blue-light-induced stomatal opening. In this paper, we report on the effects of green light pulses on phototropism in both light- and dark-grown seedlings of Arabidopsis thaliana. Green light had no effect on either red-light or blue-light-based phototropism in roots. However, in hypocotyls of dark-grown seedlings, pulses of green light significantly reduced blue-light positive phototropism while the growth rate was increased. In contrast, in hypocotyls of light-grown seedlings, green pulses significantly increased positive phototropic curvature while there was no significant effect on growth rate. The observed effects of green light may occur by perception through the phytochromes or via a novel undiscovered green light receptor. Taken together, these results suggest that care should be taken when green illumination is used as a “safe” light in studies of plant development. While green light effects may be more subtle compared to red and blue effects, monochromatic green illumination can influence the growth and development of seedlings.

Several species of bumblebees have recently experienced range contractions and possible extinctions. While threats to bees are numerous, few analyses have attempted to understand the relative importance of multiple stressors. Such analyses are critical for prioritizing conservation strategies. Here, we describe a landscape analysis of factors predicted to cause bumblebee declines in the USA. We quantified 24 habitat, land-use and pesticide usage variables across 284 sampling locations, assessing which variables predicted pathogen prevalence and range contractions via machine learning model selection techniques. We found that greater usage of the fungicide chlorothalonil was the best predictor of pathogen (Nosema bombi) prevalence in four declining species of bumblebees. Nosema bombi has previously been found in greater prevalence in some declining US bumblebee species compared to stable species. Greater usage of total fungicides was the strongest predictor of range contractions in declining species, with bumblebees in the northern USA experiencing greater likelihood of loss from previously occupied areas. These results extend several recent laboratory and semifield studies that have found surprising links between fungicide exposure and bee health. Specifically, our data suggest landscape-scale connections between fungicide usage, pathogen prevalence and declines of threatened and endangered bumblebees.

Light affects all aspects of plant growth and development from seed germination to senescence. While there has been intensive investigation of the effects of blue and red light on development and tropisms, much less is known about the specific effects of green light exposure in plants. Several recent studies demonstrate that monochromatic green light has a number of physiological effects including antagonizing light-mediated growth inhibition in hypocotyls and reversing blue-light-induced stomatal opening. In this paper, we report on the effects of green light pulses on phototropism in both light-and darkgrown seedlings of Arabidopsis thaliana. Green light had no effect on either red-light or blue-light-based phototropism in roots. However, in hypocotyls of dark-grown seedlings, pulses of green light significantly reduced blue-light positive phototropism while the growth rate was increased. In contrast, in hypocotyls of light-grown seedlings, green pulses significantly increased positive phototropic curvature while there was no significant effect on growth rate. The observed effects of green light may occur by perception through the phytochromes or via a novel undiscovered green light receptor. Taken together, these results suggest that care should be taken when green illumination is used as a \"safe\" light in studies of plant development. While green light effects may be more subtle compared to red and blue effects, monochromatic green illumination can influence the growth and development of seedlings.

Monarch butterflies are one of the best studied non-pest lepidopterans, serving as a model for migration, chemical ecology, and insect conservation. Despite the intensity with which the larvae and adults have been studied, the cryptic pupal stage is often difficult to study in the wild. It is perhaps due to this difficulty that researchers have largely overlooked monarchs’ interactions with a pupal parasitoid, Pteromalus cassotis. Using field experiments in the northern U.S. and observational data from wild collected pupae in the southern U.S., we report occurrences of this host-parasitoid interaction at sites Minnesota, Georgia, Oklahoma, Texas, and Wisconsin. At sites in Minnesota, rates of parasitism of experimentally placed monarch were highly variable, ranging from 60% in 2010 to 0% in 2013 and 2014. Observations of wild-collected pupae suggest that rates of parasitism may near 100% at some sites in the southern U.S. The number of wasps emerging from a single host ranged from 1–425 (mean  =  71). Later dissections of hosts revealed that, in some cases, dead parasitoids remained inside the host as larvae, pupae, and/or adults. Within a host, wasp sex ratios were typically female biased (median  =  91% female), as is common in gregarious parasitic hymenopterans. Infected monarch pupae at a site in Oklahoma produced more wasps per host, more male-biased sex ratios, and had higher survival than hosts from other sites. We discuss the possibility that P. cassotis is a specialist on monarchs and perhaps closely related species, based on monarchs’ sequestered cardenolides, published host records, and evidence for correlated population dynamics of this host and parasitoid.