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(1) Introduction. Although new particle formation (NPF) constitutes an important process in air, there are large uncertainties regarding which species participate in the formation of the first nanoclusters. Acid-base reactions are known generate new particles, with methanesulfonic acid (MSA) from the photooxidation of biogenic organosulfur compounds becoming more important with time relative to sulfuric acid as fossil-fuel related sources of the latter decline. Simultaneously, the use of alkanolamines in carbon capture and storage (CCS) is expected to result in increased atmospheric concentrations of these bases. This study applied a unique mass spectrometry method to examine the chemical composition of 2-10 nm particles from the MSA reaction with monoethanolamine and 4-aminobutanol, the most efficient system for NPF from MSA examined to date. (2) Methods. Thermal desorption chemical ionization mass spectrometry (TDCIMS, HToF mass analyzer, Tofwerk AG) was used to measure the size and acid-to-base molar ratios of nanoparticles formed from the reaction of MSA with multifunctional amines. A high-flow differential mobility analyzer (half-mini DMA, SEADM) was interfaced with the TDCIMS, which provides a high mobility resolution and high particle transmission in the diameter range 2-10 nm, where chemical composition measurements are the most challenging due to the very small amount of mass. With this novel combination of techniques we were able to examine MSA-amine systems either from nanoparticles exiting the outlet of a flow reactor or nanoclusters generated via electrospray. (3) Preliminary Data. These experiments show that MSA-driven acid-base reactions with monethanolamine or 4-aminobutanol are even more efficient in NPF than that of simple alkylamines, exhibiting to date the highest nanoparticle formation rates measured in laboratory flow tube studies. The observed enhancement is rooted in the presence of an -OH group on the parent molecules, which initiates a H-bond network throughout the nanoclusters. In these systems, water had only a minimal enhancing effect. We demonstrated that the nanoparticles formed in both systems are neutral (i.e. contain as much acid as base molecules) in the range 2-10 nm. This contrasts with MSA reactions from previous studies on the smallest alkylamine, methylamine, where particles smaller than 9 nm were more acidic. Investigations of reactions of MSA with a diamine (1,4-diaminobutane) showed a similar pattern of neutral particles across the diameter range studied and experiments with larger alkylamine, butylamine, are underway to probe the relationship between structure- and NPF potential from MSA. These findings highlight that there is no “one size-fits-all” regarding NPF from MSA reactions with amines and illustrates the need for studies of more complex amines to fully characterize the NPF potential of this atmospherically relevant strong acid. (4) Novel Aspect. The combination of TDCIMS with a novel particle sizing system provided the chemical composition of 2-10 nm particles. 

Biodiversity is the word used to describe the rich variety of life on Earth. Right now, Earth’s biodiversity is threatened. Museums, zoos, and other kinds of natural history collections help to protect biodiversity. One way they do this is by helping researchers study life on Earth. Another way is by teaching people, through exhibits and events. Natural history collections face many challenges. One challenge is getting enough money to stay open. Another is finding new space as collections grow. Finally, some people who want to use and learn from collections cannot access them because they are not nearby. Museum collections are now putting information on the internet, so that many people can access and use it. We can all help natural history collections to continue protecting Earth’s biodiversity by visiting them, volunteering, and donating specimens or other resources. 

Tree swallows are North American birds that can help us understand more about biology. We already know a lot about tree swallows because they are easy to work with. These birds are popular for scientists to study. We know a lot about bird health, migration, and nesting because of tree swallows. However, tree swallows are declining because of climate change, insect loss, and habitat destruction. You can help by becoming a community scientist! Tree swallows are fascinating birds that everyone can help conserve. And along the way, we can learn more about our world. 

Abstract Researchers have long examined the structure of animal advertisement signals, but comparatively little is known about how often these signals are repeated and what factors predict variation in signaling rate across species. Here, we focus on acoustic advertisement signals to test the hypothesis that calling males experience a tradeoff between investment in the duration or complexity of individual calls and investment in signaling over long time periods. This hypothesis predicts that the number of signals that a male produces per 24 h will negatively correlate with (1) the duration of sound that is produced in each call (the sum of all pulses) and (2) the number of sound pulses per call. To test this hypothesis, we measured call parameters and the number of calls produced per 24 h in 16 species of sympatric phaneropterine katydids from the Panamanian rainforest. This assemblage also provided us with the opportunity to test a second taxonomically specific hypothesis about signaling rates in taxa such as phaneropterine katydids that transition from advertisement calls to mating duets to facilitate mate localization. To establish duets, male phaneropterine katydids call and females produce a short acoustic reply. These duets facilitate searching by males, females, or both sexes, depending on the species. We test the hypothesis that males invest either in calling or in searching for females. This hypothesis predicts a negative relationship between how often males signal over 24 h and how much males move across the landscape relative to females. For the first hypothesis, there was a strong negative relationship between the number of signals and the duration of sound that is produced in each signal, but we find no relationship between the number of signals produced per 24 h and the number of pulses per signal. This result suggests the presence of cross-taxa tradeoffs that limit signal production and duration, but not the structure of individual signals. These tradeoffs could be driven by energetic limitations, predation pressure, signal efficacy, or other signaling costs. For the second hypothesis, we find a negative relationship between the number of signals produced per day and proportion of the light trap catch that is male, likely reflecting males investing either in calling or in searching. These cross-taxa relationships point to the presence of pervasive trade-offs that fundamentally shape the spatial and temporal dynamics of communication. 

Climate change models often assume similar responses to temperatures across the range of a species, but local adaptation or phenotypic plasticity can lead plants and animals to respond differently to temperature in different parts of their range. To date, there have been few tests of this assumption at the scale of continents, so it is unclear if this is a large-scale problem. Here, we examined the assumption that insect taxa show similar responses to temperature at 96 sites in grassy habitats across North America. We sampled insects with Malaise traps during 2019–2021 (N = 1041 samples) and examined the biomass of insects in relation to temperature and time of season. Our samples mostly contained Diptera (33%), Lepidoptera (19%), Hymenoptera (18%), and Coleoptera (10%). We found strong regional differences in the phenology of insects and their response to temperature, even within the same taxonomic group, habitat type, and time of season. For example, the biomass of nematoceran flies increased across the season in the central part of the continent, but it only showed a small increase in the Northeast and a seasonal decline in the Southeast and West. At a smaller scale, insect biomass at different traps operating on the same days was correlated up to ~75 km apart. Large-scale geographic and phenological variation in insect biomass and abundance has not been studied well, and it is a major source of controversy in previous analyses of insect declines that have aggregated studies from different locations and time periods. Our study illustrates that large-scale predictions about changes in insect populations, and their causes, will need to incorporate regional and taxonomic differences in the response to temperature.