Andrew Michael Durso

Populations during early stages of establishment are sensitive to forms of demographic regulation coinciding with rapid growth, which may also coincide with specific patterns of natural selection due to demographic variation. Understanding how selection varies during the establishment of new populations, however, is complicated by the constraint of knowing the precise age of a population as it grows over time. To address this, we established six brown anole (Anolis sagrei) populations on spoil islands in Florida and manipulated initial sex ratios to understand how natural selection is influenced by the demographic composition of founding populations. We found that initial sex ratios of founding populations led to age-specific patterns of natural selection. Juveniles experienced stronger selection in populations that began with a female-biased sex ratio, and the strength of natural selection on juvenile size strengthened with increasing population density. We also found substantial variation in selection, suggesting that the relationship between phenotypes and fitness across early generations of a population is not consistent over time. As a result, variation in natural selection driven by demographic aspects within populations may provide opportunities for rapid population growth and novel evolutionary trajectories during the earliest stages of establishment.

Predation by Brown Treesnakes (Boiga irregularis) has caused the decline or extinction of all native forest vertebrates on Guam, including birds, lizards, and bats. Loss of the highest-quality prey has caused shifts in Brown Treesnake size and life history. We sought to understand how reproductive condition varies among habitats island-wide, particularly comparing urban and savanna habitats (where some primarily non-native large prey remain) with prey-depauperate forest habitats. We dissected 100 snakes from each of 18 sites stratified by 6 habitat types and calculated a body condition index, relative follicle size (for females; N = 817) and relative testes size (for males; N = 992) for each. Low detection of reproductive females continues to hamper research on their biology, as only 11% of females had secondary vitellogenic follicles (N = 89). Although variation among sites within habitats was high, above-average reproductive development of both males and females was most frequently observed in urban and savanna habitats, emphasizing the potential for prey subsidies in these habitats to fuel population growth and affect invasive snake management objectives. Furthermore, the trade-off between body condition and reproductive condition appeared to be more severe in forested habitats and less severe in urban habitats for both males and females. There were few obvious seasonal patterns, although there was a slightly lower probability of females having secondary vitellogenic follicles in the wet season compared to the dry season.

Large-scale conservation of biodiversity requires understanding how species are distributed around the world. The first global delineation of freshwater ecoregions (Abell et al. 2008) integrated hydrological boundaries and fish biogeographic patterns to recognize 426 distinctive zones. Here, we update and expand that ecoregional approach to encompass every described freshwater-dependent vertebrate species: 23,130 species of fishes, birds, amphibians, reptiles, and mammals. Our database of freshwater vertebrates at the ecoregional scale (FreshVerts v1.0) includes a total of 96,129 ecoregional population records (average of 4.15 records per species, SD = 11.25) based on biogeographic databases and extensive bibliographic searches. This global attribution of all freshwater vertebrates to ecoregions provides a resource for analyzing global biodiversity, comparing biogeographic patterns among vertebrate taxa, and prioritizing efforts to conserve aquatic species across a variety of spatial scales.

Raillietiella orientalis is an invasive pulmonary parasite that is native to Southeast
Asia and Africa and is rapidly spreading throughout Florida since its initial
identification in South Florida in 2012. This obligate parasite utilizes invertebrates,
anurans, and lizards as intermediate hosts and most often infects snakes as definitive
hosts. While parasitism causes minimal fitness consequences to snakes in the native
range of R. orientalis, in the introduced range it can cause severe infections in native
snake species, sometimes leading to mortality. Through collaborative and opportunistic
sampling, we examined snakes in the southeastern United States for R. orientalis
infection. We documented 14 new Florida county records of R. orientalis infection
in snakes sampled from August 2022 through October 2024. These new localities
fill gaps in the known geographic range of R. orientalis in Florida and extend the
parasite’s range 435 km northwest into the Florida panhandle. We also document
R. orientalis infections in four wild-caught snakes from South Florida that entered
the pet trade. Human-aided dispersal of intermediate hosts and snakes, including those
in the pet trade, is likely to rapidly increase the geographic range and conservation
threat of this invasive parasite. Our results highlight the importance of monitoring
biological invasions of parasites to clarify impacts on novel host species.

Colonization of new habitats exposes populations to novel selective pressures, and the evolutionary dynamics of invasive species are determined by how the founding environment interacts with the phenotypes of invaders. Measuring these processes depends on measuring natural selection immediately upon colonization, which has been a logistical hurdle for understanding how selection operates in newly established populations. We established six brown anole (Anolis sagrei) populations on spoil islands in Florida and manipulated initial sex ratios to understand how natural selection differs based on the composition of founding populations. We found unpredictable spatial and temporal variance in natural selection, and selection increased in strength over time and with increasing adult density. The relationship between phenotypes and fitness in newly established populations may not be consistent over time. As a result, each colonization event by an invasive population provides the opportunity for a novel evolutionary trajectory towards either establishment or extirpation.

Warning coloration and Batesian mimicry are classic examples of Darwinian evolution, but empirical evolutionary patterns are often paradoxical. We test whether a new factor, trade-offs with foraging, influences the evolution of striking coloration by integrating genetic and ecological data for aposematic and mimetic snakes (Elapidae and Dipsadidae). Our phylogenetic comparison of a total of 432 species demonstrated that dramatic changes in coloration were well-predicted by the foraging strategy. Multiple tests consistently indicated that warning coloration and conspicuous mimicry were more likely to evolve in species where foraging costs of conspicuous appearance were relaxed by the poor vision of their prey or concealed habitat. Reversion to crypsis was also well-predicted by ecology for elapids, but not for dipsadids. In contrast to a theoretical prediction and general trends, snakes’ conspicuous coloration was correlated with secretive ecology, suggesting that a selection regime underlies evolutionary patterns. We also found evidence that mimicry of inconspicuous models (pitvipers) may have evolved in association with foraging demand for crypsis. These findings demonstrate that foraging is an important factor necessary to understand the evolution, persistence, and diversity of warning coloration and mimicry of snakes, highlighting the significance of additional selective factors in solving the warning coloration paradox.

Reproduction, although absolutely essential to a species' persistence, is in itself challenging. As anthropogenic change increasingly affects every landscape on Earth, it is critical to understand how specific pressures impact the reproductive efforts of individuals, which directly contribute to the success or failure of populations. However, organisms rarely encounter a single burden at a time, and the interactions of environmental challenges can have compounding effects. Understanding environmental and physiological pressures is difficult because they are often context-dependent and not generalizable, but long-term monitoring across variable landscapes and weather patterns can improve our understanding of these complex interactions. We tested the effects of urbanization, climate, and individual condition on the reproductive investment of wild side-blotched lizards ( ) by measuring physiological/reproductive metrics from six populations in urban and rural areas over six consecutive years of variable precipitation. We observed that reproductive stage affected body condition, corticosterone concentration, and oxidative stress. We also observed that reproductive patterns differed between urban and rural populations depending on rainfall, with rural animals increasing reproductive investment during rainier years compared to urban conspecifics, and that reproductive decisions appeared to occur early in the reproductive process. These results demonstrate the plastic nature of a generalist species optimizing lifetime fitness under varying conditions.

Building accurate knowledge of the identity, the geographic distribution and the evolution of species is essential for the sustainable development of humanity, as well as for biodiversity conservation. However, species identification and inventory is a difficult and costly task, requiring large-scale automated approaches. The LifeCLEF lab has been promoting and evaluating advances in this domain since 2011 through the organization of multi-year challenges. The 2024 edition presented in this article proposes five data-driven challenges as a continuation of this effort: (i) BirdCLEF: bird species recognition in audio soundscapes, (ii)FungiCLEF: fungi recognition beyond 0-1 cost, (iii) GeoLifeCLEF: remote sensing based prediction of species, (iv) PlantCLEF: Multi-species identification in vegetation plot images, and (v) SnakeCLEF: snake recognition in medically important scenarios.

Warning coloration and Batesian mimicry are classic examples of Darwinian evolution, but empirical evolutionary patterns are often paradoxical. We test whether foraging costs predict the evolution of striking coloration by integrating genetic and ecological data for aposematic and mimetic snakes (Elapidae and Dipsadidae). Our phylogenetic comparison on a total of 432 species demonstrated that dramatic changes in coloration were well predicted by foraging strategy. Multiple tests consistently indicated that warning coloration and conspicuous mimicry were more likely to evolve in species where foraging costs of conspicuous appearance were relaxed by poor vision of their prey, concealed habitat, or nocturnal activity. Reversion to crypsis was also well predicted by ecology for elapids but not for dipsadids. In contrast to a theoretical prediction and general trends, snakes' conspicuous coloration was correlated with secretive ecology, suggesting that a selection regime underlies evolutionary patterns. We also found evidence that mimicry of inconspicuous models (pitvipers) may have evolved in association with foraging demand for crypsis. These findings demonstrate that foraging is an important factor necessary to understand the evolution, persistence, and diversity of warning coloration and mimicry of snakes, highlighting the significance of additional selective factors in solving the warning coloration paradox.

Correctly identifying the strength of selection that parasites impose on hosts is key to predicting epidemiological and evolutionary outcomes of host-parasite interactions. However, behavioral changes due to infection can alter the capture probability of infected hosts and thereby make selection difficult to estimate by standard sampling techniques. Mark-recapture approaches, which allow researchers to determine if some groups in a population are less likely to be captured than others, can be used to identify infection-driven capture biases. If a metric of interest directly compares infected and uninfected populations, calculated detection probabilities for both groups may be useful in identifying bias. Here, we use an individual-based simulation to test whether changes in capture rate due to infection can alter estimates of three key metrics: 1) reduction in the reproductive success of infected parents relative to uninfected parents, 2) the relative risk of infection for susceptible genotypes compared to resistant genotypes, and 3) changes in allele frequencies between generations. We explore the direction and underlying causes of the biases that emerge from these simulations. Finally, we argue that short series of mark-recapture sampling bouts, potentially implemented in under a week, can yield key data on detection bias due to infection while not adding a significantly higher burden to disease ecology studies.