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In response to biodiversity loss and biotic community homogenization in urbanized landscapes, there are increasing efforts to conserve and increase biodiversity within urban areas. Accordingly, around the world, previously extirpated species are (re)colonizing and otherwise infiltrating urban landscapes, while other species are disappearing from these landscapes. Tracking the occurrence of traditionally urban intolerant species and loss of traditionally urban tolerant species should be a management goal of urban areas, but we generally lack tools to study this phenomenon. To address this gap, we first used species’ occurrences from iNaturalist, a large collaborative dataset of species observations, to calculate an urban association index (UAI) for 967 native animal species that occur in the city of Los Angeles. On average, the occurrence of native species was negatively associated with our composite measure of urban intensity, with the exception of snails and slugs, which instead occur more frequently in areas of increased urban intensity. Next, we assessed 8,348 0.25 x 0.25 mile grids across the City of Los Angeles to determine the average grid-level UAI scores (i.e., a summary of the UAIs present in a grid cell, which we term Community Urban Tolerance Index or CUTI). We found that areas of higher urban intensity host more urban tolerant species, but also that taxonomic groups differ in their aggregate tolerance of urban areas, and that spatial patterns of tolerance vary between groups. The framework established here has been designed to be iteratively reevaluated by city managers of Los Angeles in order to track the progress of initiatives to preserve and encourage urban biodiversity, but can be rescaled to sample different regions within the city or different cities altogether to provide a valuable tool for city managers globally.

In conifer forests of western North America, wildlife populations can change rapidly in the decade following wildfire as trees die and animals respond to concomitant resource pulses that occur across multiple trophic levels. In particular, black-backed woodpeckers ( Picoides arcticus ) show predictable temporal increases then declines following fire; this trajectory is widely believed to be a response to the woodpeckers’ main prey, woodboring beetle larvae of the families Buprestidae and Cerambycidae, but we lack understanding of how abundances of these predators and prey may be associated in time or space. Here, we pair woodpecker surveys over 10 years with surveys of woodboring beetle sign and activity, collected at 128 survey plots across 22 recent fires, to ask whether accumulated beetle sign indicates current or past black-backed woodpecker occurrence, and whether that relationship is mediated by the number of years since fire. We test this relationship using an integrative multi-trophic occupancy model. Our results demonstrate that woodboring beetle sign is a positive indicator of woodpecker presence 1–3 years following fire, an uninformative indicator from 4–6 years after fire, and a negative indicator beginning 7 years following fire. Woodboring beetle activity, itself, is temporally variable and dependent on tree species composition, with beetle sign generally accumulating over time, particularly in stands with diverse tree communities, but decreasing over time in Pinus -dominated stands where faster bark decay rates lead to brief pulses of beetle activity followed by rapid degradation of tree substrate and accumulated beetle sign. Altogether, the strong connections of woodpecker occurrence to beetle activity support prior hypotheses of how multi-trophic interactions govern rapid temporal dynamics of primary and secondary consumers in burned forests. While our results indicate that beetle sign is, at best, a rapidly shifting and potentially misleading measure of woodpecker occurrence, the better we understand the interacting mechanisms underlying temporally dynamic systems, the more successfully we will be able to predict the outcomes of management actions.

Bees are essential pollinators for many flowering plants, including agriculturally important crops such as apple. As geographic ranges of bees or their host plants change as a result of human activities, we need to identify pathogens that could be transmitted among newly sympatric species to evaluate and anticipate their effects on bee communities. We used PCR screening and DNA sequencing to evaluate exposure to potentially disease-causing microorganisms in a pollinator of apple, the horned mason bee (Osmia cornifrons). We did not detect microsporidia, Wolbachia, or trypanosomes, which are common pathogens of bees, in any of the hundreds of mason bees screened. We did detect both pathogenic and apathogenic (saprophytic) fungal species in the genus Ascosphaera (chalkbrood), an unidentified species of Aspergillus fungus, and a strain of bacteria in the genus Paenibacillus that is probably apathogenic. We detected pathogenic fungal strains in asymptomatic adult bees that therefore may be carriers of disease. We demonstrate that fungi from the genus Ascosphaera have been transported to North America along with the bee from its native range in Japan, and that O. cornifrons is exposed to fungi previously only identified from nests of other related bee species. Further study will be required to quantify pathogenicity and health effects of these different microbial species on O. cornifrons and on closely-related native North American mason bees that may now be exposed to novel pathogens. A global perspective is required for pathogen research as geographic ranges of insects and microorganisms shift due to intentional or accidental introductions.

Geographically isolated populations of birds often differ in song. Because birds often choose mates on the basis of their song, song differentiation between isolated populations constitutes a behavioral barrier to reproduction. If this barrier is judged to be sufficiently strong, then isolated populations with divergent songs may merit classification as distinct species under the biological species concept. We used a dataset of 72 pairs of related but allopatric Neotropical passerines (“taxon pairs”) to compare 2 methods for measuring song divergence between isolated populations: statistical analysis of 7 acoustic traits measured from spectrograms, and field playback experiments that “ask the birds themselves” if they perceive foreign song as conspecific or not. We report 4 main findings: (1) Behavioral discrimination (defined as failure to approach the speaker in response to allopatric song) is nonlinearly related to divergence in acoustic traits; discrimination is variable at low to moderate levels of acoustic divergence, but nearly uniformly high at high levels. (2) The same nonlinear relationship held for both song learners (oscines) and nonlearners (suboscines). (3) Song discrimination is not greater in taxon pairs ranked as species compared to taxon pairs ranked as subspecies. (4) Behavioral responses to allopatric song are symmetric within a taxon pair. We conclude (1) that playback experiments provide a stronger measure of species recognition relevant to premating reproductive isolation than do acoustic trait analyses, at least when divergence in acoustic traits is low to moderate; and (2) that playback experiments are useful for defining species limits and can help address the latitudinal gradient in taxonomy, which arises because species are defined more broadly in the tropics than in the temperate zone. To this end, we suggest that 21 Neotropical taxon pairs that are currently ranked as subspecies, but that show strong behavioral discrimination in response to allopatric song, merit classification as distinct biological species.

Biodiversity is in crisis, and insects are no exception. To understand insect population and community trends globally, it is necessary to identify and synthesize diverse datasets representing different taxa, regions, and habitats. The relevant literature is, however, vast and challenging to aggregate. The Entomological Global Evidence Map (EntoGEM) project is a systematic effort to search for and catalogue studies with long‐term data that can be used to understand changes in insect abundance and diversity. Here, we present the overall EntoGEM framework and results of the first completed subproject of the systematic map, which compiled sources of information about changes in dragonfly and damselfly (Odonata) occurrence, abundance, biomass, distribution, and diversity. We identified 45 multi‐year odonate datasets, including 10 studies with data that span more than 10 years. If data from each study could be gathered or extracted, these studies could contribute to analyses of long‐term population trends of this important group of indicator insects. The methods developed to support the EntoGEM project, and its framework for synthesizing a vast literature, have the potential to be applied not only to other broad topics in ecology and conservation, but also to other areas of research where data are widely distributed. A systematic approach to reviewing the literature can reduce bias in the types of datasets identified to understand conservation issues. Here, we present a community‐driven evidence synthesis framework that can be adapted to gather and assess evidence from many broad topics in conservation and apply the approach to gather datasets documenting long‐term changes in insect populations.

In animal societies, behavioral idiosyncrasies of the individuals often guide which tasks theyshould perform. Such personality-specific task participation can increase individual task efficiency,thereby improving group performance. While several recent studies have documented group-levelbenefits of within-group behavioral （i.e., personality） diversity, how these benefits are realized atthe individual level is unclear. Here we probe the individual-level benefits of personality-driven taskparticipation in the social spider Stegodyphus dumicola. In S. dumicola, the presence of at leastone highly bold individual catalyzes foraging behavior in shy colony members, and all group con-stituents heavily compete for prey. We assessed boldness by examining how quickly spidersresumed normal movement after a simulated predator attack. We test here whether （1） participantsin collective foraging gain more mass from prey items and （2） whether bold individuals are less re-sistant to starvation than shy spiders, which would motivate the bold individuals to forage more.Next, we assembled colonies of shy spiders with and without a bold individual, added one preyitem, and then tracked the mass gain of each individual spider after this single feeding event. Wefound that spiders that participated in prey capture （whether bold or shy） gained more mass thannonparticipators, and colonies containing a single bold spider gained more total mass than purelyshy colonies. We also found that bold spiders participated in more collective foraging events andwere more susceptible to starvation than shy spiders, suggesting that the aggressive foraging ofbold individuals may represent a strategy to offset starvation risk. These findings add to the bodyof evidence that animal personality can shape social organization, individual performance, andgroup success.

Plasticity is often thought to accelerate trait evolution and speciation. For example, plasticity in birdsong may partially explain why clades of song learners are more diverse than related clades with innate song. This “song learning” hypothesis predicts that (1) differences in song traits evolve faster in song learners, and (2) behavioral discrimination against allopatric song (a proxy for premating reproductive isolation) evolves faster in song learners. We tested these predictions by analyzing acoustic traits and conducting playback experiments in allopatric Central American sister pairs of song learning oscines (N = 42) and nonlearning suboscines (N = 27). We found that nonlearners evolved mean acoustic differences slightly faster than did leaners, and that the mean evolutionary rate of song discrimination was 4.3 times faster in nonlearners than in learners. These unexpected results may be a consequence of significantly greater variability in song traits in song learners (by 54–79 %) that requires song-learning oscines to evolve greater absolute differences in song before achieving the same level of behavioral song discrimination as nonlearning suboscines. This points to “a downside of learning” for the evolution of species discrimination, and represents an important example of plasticity reducing the rate of evolution and diversification by increasing variability.

Adaptation is evolution in response to natural selection. Hence, an adaptation is expected to originate simultaneously with the acquisition of a particular selective environment. Here we test whether long legs evolve in oil-collecting Rediviva bees when they come under selection by long-spurred, oil-secreting flowers. To quantify the selective environment, we drew a large network of the interactions between Rediviva species and oil-secreting plant species. The selective environment of each bee species was summarized as the average spur length of the interacting plant species weighted by interaction frequency. Using phylogenetically independent contrasts, we calculated divergence in selective environment and evolutionary divergence in leg length between sister species (and sister clades) of Rediviva. We found that change in the selective environment explained 80% of evolutionary change in leg length, with change in body size contributing an additional 6% of uniquely explained variance. The result is one of four proposed steps in testing for plant–pollinator coevolution.

In conifer forests of western North America, wildlife populations can change rapidly in the decade following wildfire as trees die and animals respond to concomitant resource pulses that occur across multiple trophic levels. In particular, black-backed woodpeckers (Picoides arcticus) show predictable temporal increases then declines following fire; this trajectory is widely believed to be a response to the woodpeckers' main prey, woodboring beetle larvae of the families Buprestidae and Cerambycidae, but we lack understanding of how abundances of these predators and prey may be associated in time or space. Here, we pair woodpecker surveys over 10 years with surveys of woodboring beetle sign and activity, collected at 128 survey plots across 22 recent fires, to ask whether accumulated beetle sign indicates current or past black-backed woodpecker occurrence, and whether that relationship is mediated by the number of years since fire. We test this relationship using an integrative multi-trophic occupancy model. Our results demonstrate that woodboring beetle sign is a positive indicator of woodpecker presence 1-3 years following fire, an uninformative indicator from 4-6 years after fire, and a negative indicator beginning 7 years following fire. Woodboring beetle activity, itself, is temporally variable and dependent on tree species composition, with beetle sign generally accumulating over time, particularly in stands with diverse tree communities, but decreasing over time in Pinus-dominated stands where faster bark decay rates lead to brief pulses of beetle activity followed by rapid degradation of tree substrate and accumulated beetle sign. Altogether, the strong connections of woodpecker occurrence to beetle activity support prior hypotheses of how multi-trophic interactions govern rapid temporal dynamics of primary and secondary consumers in burned forests. While our results indicate that beetle sign is, at best, a rapidly shifting and potentially misleading measure of woodpecker occurrence, the better we understand the interacting mechanisms underlying temporally dynamic systems, the more successfully we will be able to predict the outcomes of management actions.

Predation is a ubiquitous threat that often plays a central role in determining community dynamics. Predators can impact prey species by directly consuming them, or indirectly causing prey to modify their behavior. Direct consumption has classically been the focus of research on predator-prey interactions, but substantial evidence now demonstrates that the indirect effects of predators on prey populations are at least as strong as, if not stronger than, direct consumption. Social animals, particularly those that live in confined colonies, rely on coordinated actions that may be vulnerable to the presence of a predator, thus impacting the society's productivity and survival. To examine the effect of predators on the behavior of social animal societies, we observed the collective foraging of social spider colonies (Stegodyphus dumicola) when they interact with dangerous predatory ants either directly, indirectly, or both. We found that when colonies were exposed directly and indirectly to ant cues, they attacked prey with approximately 40-50% fewer spiders, and 40-90% slower than colonies that were not exposed to any predator cues. Furthermore, exposure to predatory ants disassociated the well-documented positive relationship between colony behavioral composition (proportion of bold spiders) and foraging aggressiveness (number of attackers) in S. dumicola, which is vital for colony growth. Thus, the indirect effects of predator presence may limit colony success. These results suggest that enemy presence could compromise the organizational attributes of animal societies.