Where Is Natural History in Ecological, Evolutionary, and Behavioral Science?

Population and community ecology: past progress and future directions

Population and community ecology as a science are about 100 years old, and we discuss here our opinion of what approaches have progressed well and which point to possible future directions. The three major threads within population and community ecology are theoretical ecology, statistical tests and models, and experimental ecology. We suggest that our major objective is to understand what factors determine the distribution and abundance of organisms within populations and communities, and we evaluate these threads against this major objective. Theoretical ecology is elegant and compelling and has laid the groundwork for achieving our overall objectives with useful simple models. Statistics and statistical models have contributed informative methods to analyze quantitatively our understanding of distribution and abundance for future research. Population ecology is difficult to carry out in the field, even though we may have all the statistical methods and models needed to achieve results. Community ecology is growing rapidly with much description but less understanding of why changes occur. Biodiversity science cuts across all these subdivisions but rarely digs into the necessary population and community science that might solve conservation problems. Climate change affects all aspects of ecology but to assume that everything in population and community ecology is driven by climate change is oversimplified. We make recommendations on how to advance the field with advice for present and future generations of population and community ecologists.

Let's talk about sex: Why reproductive systems matter for understanding algae

Sex is a crucial process that has molecular, genetic, cellular, organismal, and population-level consequences for eukaryotic evolution. Eukaryotic life cycles are composed of alternating haploid and diploid phases but are constrained by the need to accommodate the phenotypes of these different phases. Critical gaps in our understanding of evolutionary drivers of the diversity in algae life cycles include how selection acts to stabilize and change features of the life cycle. Moreover, most eukaryotes are partially clonal, engaging in both sexual and asexual reproduction. Yet, our understanding of the variation in their reproductive systems is largely based on sexual reproduction in animals or angiosperms. The relative balance of sexual versus asexual reproduction not only controls but also is in turn controlled by standing genetic variability, thereby shaping evolutionary trajectories. Thus, we must quantitatively assess the consequences of the variation in life cycles on reproductive systems. Algae are a polyphyletic group spread across many of the major eukaryotic lineages, providing powerful models by which to resolve this knowledge gap. There is, however, an alarming lack of data about the population genetics of most algae and, therefore, the relative frequency of sexual versus asexual processes. For many algae, the occurrence of sexual reproduction is unknown, observations have been lost in overlooked papers, or data on population genetics do not yet exist. This greatly restricts our ability to forecast the consequences of climate change on algal populations inhabiting terrestrial, aquatic, and marine ecosystems. This perspective summarizes our extant knowledge and provides some future directions to pursue broadly across micro- and macroalgal species.

Plant interaction networks reveal the limits of our understanding of diversity maintenance

Species interactions are key drivers of biodiversity and ecosystem stability. Current theoretical frameworks for understanding the role of interactions make many assumptions which unfortunately, do not always hold in natural, diverse communities. This mismatch extends to annual plants, a common model system for studying coexistence, where interactions are typically averaged across environmental conditions and transitive competitive hierarchies are assumed to dominate. We quantify interaction networks for a community of annual wildflowers in Western Australia across a natural shade gradient at local scales. Whilst competition dominated, intraspecific and interspecific facilitation were widespread in all shade categories. Interaction strengths and directions varied substantially despite close spatial proximity and similar levels of local species richness, with most species interacting in different ways under different environmental conditions. Contrary to expectations, all networks were predominantly intransitive. These findings encourage us to rethink how we conceive of and categorize the mechanisms driving biodiversity in plant systems.

The iconic cactus of the Caatinga dry forest, Cereus jamacaru (Cactaceae) has high sphingophily specialization and pollinator dependence

Cereus jamacaru is a cactus distributed in Northeastern Brazil, with high symbolic value to this region. However, the interaction, behavior and the role of pollinators remains poorly understood. Here, we investigate the reproductive biology, addressing the ecological significance of floral attributes, including details about floral signaling. The study was carried at three areas of the Caatinga, in 2015, 2017 and 2021. We analyzed the floral morphometry, volume and concentration of the nectar, and characterized the colour and scent of flowers. Additionally, we described the pollinator behavior and performed controlled pollination experiments. The 'Mandacaru' is self-incompatible, has nocturnal anthesis and the nectar is accumulated as droplets in a long hypanthial tube. The flowers have a reflective pattern with a dark outer surface and a white inner surface. (E)-nerolidol is the major component (87.4%) of its floral perfume. We registered the sphingid moth Cocytius antaeus visiting the flowers. The floral attributes, attractants and rewards drives to a sphingophily, and the pollination treatments showed the dependence to fruit set by C. antaeus, the pollinator registered. In this case, if the apparent lack of pollinator diversity encompasses its entire range, the loss of the hawkmoth could severely impact the reproductive success of the cactus.

Capuchin monkey (Sapajus spp.) diet: current knowledge, gaps, and future directions

Knowledge of the feeding habits of primate species is important for an understanding of their natural history and ecological interactions between their groups, and their interactions with their environments. Capuchin monkeys (Sapajus spp.) present significant diet flexibility and are a good model for investigating diet diversity between species. We undertook a systematic literature review of publications on the diet of free-living Sapajus spp. groups by using the Web of Science platform. We performed scientometric analyses of the objectives and hypotheses of the reviewed works, identified knowledge gaps, and evaluated the composition of each group's diet. Our results indicate geographic and taxonomic biases among the 59 published studies that we examined. The studies were focused on Sapajus nigritus, Sapajus libidinosus, and Sapajus apella, and undertaken in long-term study sites. Foraging and behavioral aspects of how food is processed were recurring themes. Capuchin monkeys increase their consumption of anthropogenic food according to its supply. Despite the similar objectives of these studies, standardized data collection protocols were not employed. Although Sapajus spp. are widely distributed and are used for cognitive studies, basic aspects of their natural history, such as their diet, remain unknown. We emphasize the importance of undertaking studies on this genus to fill the identified knowledge gaps, and propose that investigations should be carried out on the effects of dietary changes on individuals and groups. We stress that, as the Neotropical region is one of those most affected by anthropogenic impacts, opportunities to study these primates in their natural environments are diminishing daily.

Filling the gap: Noteworthy herpetological discoveries in North West Province, South Africa

The North West Province, South Africa, is centrally situated in southern Africa and is characterised by savannah with a mesic, temperate climate in the east and a hot, arid climate in the west. While the eastern region is fairly well-documented for herpetofauna, the arid central and western regions are poorly surveyed. Given that the Province has been targeted by the national government for development of infrastructure, the overall deficiency of biodiversity data could result in impact assessments that are not well-informed. We, therefore, carried out herpetofaunal surveys over two years (2019–2020) in the North West Province to improve knowledge on the distributions of reptiles and amphibians. Our surveys added a total of 578 new records to an earlier baseline of 1340 records. In addition, over 300 records were added to a citizen-science platform in connection with our surveys. As compared to the previous 100 years, our surveys increased the herpetofaunal dataset by 68% in just two years, increased geographic coverage by 20% and brought the total number of species with accurate records for the Province to 102 reptiles and 23 amphibians. We also recorded range extensions for five reptile species and confirmed the presence of Dendroaspis polylepis (Black Mamba) in the west where it had been last recorded in 1996. Our surveys resulted in a significant increase in biodiversity data for the Province and provided a better foundation for spatial planning that accounts for biodiversity and the maintenance of ecological function.

Ecology: Lifting the curtain on higher-order interactions

Higher-order interactions - the modification of interactions between a species pair by a third - remain poorly understood in nature. A new study manipulates pairwise and higher-order interactions in the field, offering exciting new insights into how higher-order interactions contribute to coexistence.

Free-ranging Southern anteater mating behavior: Contribution to Tamandua natural history

Observing behavior in wild Southern Anteaters (Tamandua tetradactyla) allows Xenarthran researchers to gain perspective on natural history of this neotropical scansorial species. We describe the use of the prehensile tail to facilitate copulation for a pair in southeastern Brazil, a novel observation for this species. This detailed account of mating behavior in lesser anteaters is one of very few in the literature and contributes to basic knowledge of this group.

Seasonality in Kgalagadi Lizards: Inferences from Legacy Data

AbstractAn ecological issue can best be studied by gathering original data that are specifically targeted for that issue. But ascertaining-a priori-whether a novel issue will be worth exploring can be problematic without background data. However, an issue's potential merit can sometimes be evaluated by repurposing legacy or other data that had been gathered for unrelated purposes but that are nonetheless relevant. Our present project was initially motivated by an ecological trade-off-proposed eight decades ago-involving the depth at which desert reptiles overwintered. To address those and related issues, we repurposed our five-decades-old natural history data for 18 species of Kgalagadi lizards and then explored the seasonal ecology of these lizards, emphasizing winter. Our data were not gathered for a study of seasonal ecology but nonetheless inform diverse seasonal patterns for a major community of lizards. However, repurposed data (whether recent or legacy) present challenges and ambiguities, and we suggest targeted, next-step studies of seasonal ecology that can circumvent limitations and ambiguities.

Building on 150 Years of Knowledge: The Freshwater Isopod Asellus aquaticus as an Integrative Eco-Evolutionary Model System

Interactions between organisms and their environments are central to how biological diversity arises and how natural populations and ecosystems respond to environmental change. These interactions involve processes by which phenotypes are affected by or respond to external conditions (e.g., via phenotypic plasticity or natural selection) as well as processes by which organisms reciprocally interact with the environment (e.g., via eco-evolutionary feedbacks). Organism-environment interactions can be highly dynamic and operate on different hierarchical levels, from genes and phenotypes to populations, communities, and ecosystems. Therefore, the study of organism-environment interactions requires integrative approaches and model systems that are suitable for studies across different hierarchical levels. Here, we introduce the freshwater isopod Asellus aquaticus, a keystone species and an emerging invertebrate model system, as a prime candidate to address fundamental questions in ecology and evolution, and the interfaces therein. We review relevant fields of research that have used A. aquaticus and draft a set of specific scientific questions that can be answered using this species. Specifically, we propose that studies on A. aquaticus can help understanding (i) the influence of host-microbiome interactions on organismal and ecosystem function, (ii) the relevance of biotic interactions in ecosystem processes, and (iii) how ecological conditions and evolutionary forces facilitate phenotypic diversification.

Evolution in Cities

Although research performed in cities will not uncover new evolutionary mechanisms, it could provide unprecedented opportunities to examine the interplay of evolutionary forces in new ways and new avenues to address classic questions. However, while the variation within and among cities affords many opportunities to advance evolutionary biology research, careful alignment between how cities are used and the research questions being asked is necessary to maximize the insights that can be gained. In this review, we develop a framework to help guide alignment between urban evolution research approaches and questions. Using this framework, we highlight what has been accomplished to date in the field of urban evolution and identify several up-and-coming research directions for further expansion. We conclude that urban environments can be used as evolutionary test beds to tackle both new and long-standing questions in evolutionary biology.

The promises and challenges of archiving insect behavior and natural history in a changing world

Insect behavioral ecologists are not routinely archiving their behavioral media files and natural history observations. This is especially problematic because most behaviors are not preserved by the physical specimens stored in typical natural history collections. Improving the reporting and archiving of insect behavior and natural history data holds the promise of allowing scientists to track real-time responses of animals to global change and will preserve aspects of natural history that might otherwise be lost due to extinctions. Here we argue that behavioral ecologists should work to preserve and archive raw media files and field notes related to behavior and natural history of their study organisms. One major mechanism to incentivize archiving of such data would be for journals to develop policies for archiving of natural history data that is the focus of the paper or ancillary information collected about study subjects. Buy in from researchers, journals, and funding agencies will be needed to make substantial changes in data archiving.

Strong foraging preferences for Ribes alpinum (Saxifragales: Grossulariaceae) in the polyphagous caterpillars of Buff-tip moth Phalera bucephala (Lepidoptera: Notodontidae)

Herbivorous insects such as butterflies and moths are essential to natural and agricultural systems due to pollination and pest outbreaks. However, our knowledge of butterflies' and moths' nutrition is fragmented and limited to few common, charismatic, or problematic species.This gap precludes our complete understanding of herbivorous insects' natural history, physiological and behavioral adaptations that drive how species interact with their environment, the consequences of habitat fragmentation and climate change to invertebrate biodiversity, and pest outbreak dynamics.Here, we first report a population of the Buff-tip moth Phalera bucephala (Lepidoptera: Notodontidae) feeding on a previously unknown family of host plants, the mountain currant Ribes alpinum (Saxifragales: Grossulariaceae). This is the first report of a Notodontid moth feeding on Grossulariaceae hosts.Using no-choice and choice assays, we showed that P. bucephala has strong foraging preferences for a previously unknown hosts, the R. alpinum but also, although to a smaller extent, R. uva-crispa compared with a previously known host (the Norway maple Acer sp.).These findings demonstrate that P. bucephala feed on-and show strong preference for Grossulariaceae host plants, indicating flexible physiological mechanisms to accommodate hosts plants from various families. This makes this species a potential model organism to study the behavioral and physiological mechanisms underpinning insect-plant interactions and diet breadth evolution.We discuss the broad ecological implications of these observations to the biology of the species, the potential negative effects of interspecific competition with endemic specialist moths, and highlight questions for future research.

Natural history of model organisms: The secret (group) life of Drosophila melanogaster larvae and why it matters to developmental ecology

Model organisms such as Drosophila melanogaster have been key tools for advancing our fundamental and applied knowledge in biological and biomedical sciences. However, model organisms have become intertwined with the idea of controlled and stable laboratory environments, and their natural history has been overlooked.In holometabolous insects, lack of natural history information on larval ecology has precluded major advances in the field of developmental ecology, especially in terms of manipulations of population density early in life (i.e., larval density). This is because of relativistic and to some extent, arbitrary methodologies employed to manipulate larval densities in laboratory studies. As a result, these methodologies render comparisons between species impossible, precluding our understanding of macroevolutionary responses to population densities during development that can be derived from comparative studies.We recently proposed a new conceptual framework to address this issue, and here, we provide the first natural history investigation of Drosophila melanogaster larval density under such framework. First, we characterized the distribution of larval densities in a wild population of D. melanogaster using rotting apples as breeding substrate in a suburban area in Sweden.Next, we compiled the commonly used methodologies for manipulating larval densities in laboratory studies from the literature and found that the majority of laboratory studies identified did not manipulate larval densities below or above the densities observed in nature, suggesting that we have yet to study true life history and physiological responses to low and high population densities during D. melanogaster development.This is, to our knowledge, the first direct natural history account of larval density in nature for this model organism. Our study paves the way for a more integrated view of organismal biology which re-incorporates natural history of model organisms into hypothesis-driven research in developmental ecology.

Integrative developmental ecology: a review of density-dependent effects on life-history traits and host-microbe interactions in non-social holometabolous insects

Population density modulates a wide range of eco-evolutionary processes including inter- and intra-specific competition, fitness and population dynamics. In holometabolous insects, the larval stage is particularly susceptible to density-dependent effects because the larva is the resource-acquiring stage. Larval density-dependent effects can modulate the expression of life-history traits not only in the larval and adult stages but also downstream for population dynamics and evolution. Better understanding the scope and generality of density-dependent effects on life-history traits of current and future generations can provide useful knowledge for both theory and experiments in developmental ecology. Here, we review the literature on larval density-dependent effects on fitness of non-social holometabolous insects. First, we provide a functional definition of density to navigate the terminology in the literature. We then classify the biological levels upon which larval density-dependent effects can be observed followed by a review of the literature produced over the past decades across major non-social holometabolous groups. Next, we argue that host-microbe interactions are yet an overlooked biological level susceptible to density-dependent effects and propose a conceptual model to explain how density-dependent effects on host-microbe interactions can modulate density-dependent fitness curves. In summary, this review provides an integrative framework of density-dependent effects across biological levels which can be used to guide future research in the field of ecology and evolution.