Enhancing scientific and community capacity to conserve Central African Lepidoptera

Research on the ecology and conservation of Lepidoptera (and other species) has historically neglected tropical diversity – but the Lepidoptera of tropical Africa have been particularly understudied. Central Africa represents a major centre of biodiversity for butterflies, moths and other taxa but major threats including habitat loss, habitat degradation/ disturbance and climate change are threatening their persistence. Additionally, a range of obstacles to research and conservation are apparent in Central Africa, including major socioeconomic disparity, persistent armed conflicts, corruption, and a lack of local resources (e.g., funding and museums). Here we outline the history of research on the butterflies of Central Africa and highlight the importance of further conservation efforts in maintaining the biodiversity of Lepidoptera and other understudied insects in the region. Proactive measures acknowledging the prevailing regional challenges must be taken immediately. Among the major recommendations, we suggest: 1) enhancing museum collections, 2) facilitating strong scientific collaboration that enhances local capacity, 3) ensuring that funded projects are not disrupted by corruption, and 4) working to advance the socioeconomic status of local communities. Potential for scientific and community advancement in the region is substantial if investment and research efforts are targeted effectively

Seasonal Polyphenism in Bicyclus dorothea (Lepidoptera: Nymphalidae) Across Different Habitats in Cameroon

Many organisms exhibit changes in phenotypic traits as a response to seasonal environmental variation. We investigated the role of habitat in generating seasonal polyphenism in different populations of the light bush brown butterfly Bicyclus dorothea (Cramer, 1779) (Lepidoptera: Nymphalidae) in Cameroon. Butterflies were caught during the wet and dry seasons across four localities representing two distinct habitats, namely forest and ecotone (forest-savanna transition zone) over a 2-yr period (2015-2016). We found distinct variation in the wing pattern characteristics of butterflies in response to seasonality and habitat. Specifically we observed that: 1) all wing characters are not seasonally plastic in B. dorothea; 2) populations from ecotone tend to be more variable, with individuals exhibiting wings with large spots during the wet season and very reduced spots in the dry season while in forest populations, individuals exhibit wings with large spots during the wet season, but in the dry season, spots are not as greatly reduced as their ecotone counterparts; 3) this polyphenism in B. dorothea alternated consistently during the wet and dry seasons over the 2 yr of sampling. Bicyclus species have become a textbook example of seasonal polyphenism while this study extends this model system to the unique forest-ecotone gradient of Central Africa and demonstrates the complexity of seasonal forms in different habitats

Strong habitat-specific phenotypic plasticity but no genome-wide differentiation across a rainforest gradient in an African butterfly

Habitat-specific thermal responses are well documented in various organisms and likely determine the vulnerability of populations to climate change. However, the underlying roles of genetics and plasticity that shape such habitat-specific patterns are rarely investigated together. Here we examined the thermal plasticity of the butterfly Bicyclus dorothea originating from rainforest and ecotone habitats in Cameroon under common garden conditions. We also sampled wild-caught butterflies from forest and ecotone sites and used RADseq to explore genome-wide population differentiation. We found differences in the level of phenotypic plasticity across habitats. Specifically, ecotone populations exhibited greater sensitivity in wing eyespot features with variable development temperatures relative to rainforest populations. Known adaptive roles of wing eyespots in Bicyclus species suggest that this morphological plasticity is likely under divergent selection across environmental gradients. However, we found no distinct population structure of genome-wide variation between habitats, suggesting high level of ongoing gene flow between habitats is homogenizing most parts of the genome

Warming threat compounds habitat degradation impacts on a tropical butterfly community in Vietnam

AbstractSpecies are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10~years of butterfly surveys (2003–2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested world-wide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously

Past and future decline of tropical pelagic biodiversity

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by the National Academy of Sciences in PNAS on 26/05/2020.Available online: https://www.pnas.org/content/pnas/117/23/12891.full.pdfA major research question concerning global pelagic biodiversity remains unanswered: when did the apparent tropical biodiversity depression (i.e., bimodality of latitudinal diversity gradient [LDG]) begin? The bimodal LDG may be a consequence of recent ocean warming or of deep-time evolutionary speciation and extinction processes. Using rich fossil datasets of planktonic foraminifers, we show here that a unimodal (or only weakly bimodal) diversity gradient, with a plateau in the tropics, occurred during the last ice age and has since then developed into a bimodal gradient through species distribution shifts driven by postglacial ocean warming. The bimodal LDG likely emerged before the Anthropocene and industrialization, and perhaps ∼15,000 y ago, indicating a strong environmental control of tropical diversity even before the start of anthropogenic warming. However, our model projections suggest that future anthropogenic warming further diminishes tropical pelagic diversity to a level not seen in millions of years.acceptedVersio

Increased habitat availability as revealed by LiDAR contributes to the tropicalization of a subtropical butterfly community

Species redistribution through climate change remains a global problem. However, factors such as habitat availability can complicate the attribution of species distribution shifts. We used habitat metrics derived from repeated airborne LiDAR surveys in 2010 to 2020 to examine the underlying causes for the establishment of new butterfly species in Hong Kong. For six species newly arrived since 2000, we built species distribution models using the Random Forest algorithm based on LiDAR data from 2020 to characterize species' preferred habitats across the region. Through hindcasting, we applied the model to LiDAR data from 2010 to observe any changes in the availability of preferred habitat. We found widespread vertical forest growth across Hong Kong and increased probability of occurrence based on increased habitat availability for all six species. The underlying habitat drivers, however, varied significantly across species; two species (Lethe chandica, Notocrypta paralysos) were associated with closed forest while two other species (Prosotas dubiosa, Prosotas nora) were associated with urbanicity. Our results highlight how changes in habitat can occur concurrently with climatic change and together drive the redistribution of biodiversity. Particularly for vertically complex tropical forests, airborne LiDAR data can be leveraged to observe changes in habitat complexity and how these relate to shifts in species distributions

BioTIME: A database of biodiversity time series for the Anthropocene.

MotivationThe BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time series. Our goal is to accelerate and facilitate quantitative analysis of temporal patterns of biodiversity in the Anthropocene.Main types of variables includedThe database contains 8,777,413 species abundance records, from assemblages consistently sampled for a minimum of 2 years, which need not necessarily be consecutive. In addition, the database contains metadata relating to sampling methodology and contextual information about each record.Spatial location and grainBioTIME is a global database of 547,161 unique sampling locations spanning the marine, freshwater and terrestrial realms. Grain size varies across datasets from 0.0000000158 km2 (158 cm2) to 100 km2 (1,000,000,000,000 cm2).Time period and grainBioTIME records span from 1874 to 2016. The minimal temporal grain across all datasets in BioTIME is a year.Major taxa and level of measurementBioTIME includes data from 44,440 species across the plant and animal kingdoms, ranging from plants, plankton and terrestrial invertebrates to small and large vertebrates.Software format.csv and .SQL

Predation and infanticide influence ideal free choice by a parrot occupying heterogeneous tropical habitats

The ideal free distribution (IFD) predicts that organisms will disperse to sites that maximize their fitness based on availability of resources. Habitat heterogeneity underlies resource variation and influences spatial variation in demography and the distribution of populations. We relate nest site productivity at multiple scales measured over a decade to habitat quality in a box-nesting population of Forpus passerinus (green-rumped parrotlets) in Venezuela to examine critical IFD assumptions. Variation in reproductive success at the local population and neighborhood scales had a much larger influence on productivity (fledglings per nest box per year) than nest site or female identity. Habitat features were reliable cues of nest site quality. Nest sites with less vegetative cover produced greater numbers of fledglings than sites with more cover. However, there was also a competitive cost to nesting in high-quality, low-vegetative cover nest boxes, as these sites experienced the most infanticide events. In the lowland local population, water depth and cover surrounding nest sites were related with F. passerinus productivity. Low vegetative cover and deeper water were associated with lower predation rates, suggesting that predation could be a primary factor driving habitat selection patterns. Parrotlets also demonstrated directional dispersal. Pairs that changed nest sites were more likely to disperse from poor-quality nest sites to high-quality nest sites rather than vice versa, and juveniles were more likely to disperse to, or remain in, the more productive of the two local populations. Parrotlets exhibited three characteristics fundamental to the IFD: habitat heterogeneity within and between local populations, reliable habitat cues to productivity, and active dispersal to sites of higher fitness

Higher predation risk for insect prey at low latitudes and elevations

Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution

Global Spore Sampling Project: A global, standardized dataset of airborne fungal DNA

Novel methods for sampling and characterizing biodiversity hold great promise for re-evaluating patterns of life across the planet. The sampling of airborne spores with a cyclone sampler, and the sequencing of their DNA, have been suggested as an efficient and well-calibrated tool for surveying fungal diversity across various environments. Here we present data originating from the Global Spore Sampling Project, comprising 2,768 samples collected during two years at 47 outdoor locations across the world. Each sample represents fungal DNA extracted from 24 m3 of air. We applied a conservative bioinformatics pipeline that filtered out sequences that did not show strong evidence of representing a fungal species. The pipeline yielded 27,954 species-level operational taxonomic units (OTUs). Each OTU is accompanied by a probabilistic taxonomic classification, validated through comparison with expert evaluations. To examine the potential of the data for ecological analyses, we partitioned the variation in species distributions into spatial and seasonal components, showing a strong effect of the annual mean temperature on community composition.publishedVersio