A sex-linked supergene with large effects on sperm traits has little impact on reproductive traits in female zebra finches.

Despite constituting an essential component of fitness, reproductive success can vary remarkably between individuals and the causes of such variation are not well understood across taxa. In the zebra finch-a model songbird, almost all the variation in sperm morphology and swimming speed is maintained by a large polymorphic inversion (commonly known as a supergene) on the Z chromosome. The relationship between this polymorphism and reproductive success is not fully understood, particularly for females. Here, we explore the effects of female haplotype, and the combination of male and female genotype, on several primary reproductive traits in a captive population of zebra finches. Despite the inversion polymorphism's known effects on sperm traits, we find no evidence that inversion haplotype influences egg production by females or survival of embryos through to hatching. However, our findings do reinforce existing evidence that the inversion polymorphism is maintained by a heterozygote advantage for male fitness. This work provides an important step in understanding the causes of variation in reproductive success in this model species.

Predator-induced shape plasticity in Daphnia pulex.

All animals and plants respond to changes in the environment during their life cycle. This flexibility is known as phenotypic plasticity and allows organisms to cope with variable environments. A common source of environmental variation is predation risk, which describes the likelihood of being attacked and killed by a predator. Some species can respond to the level of predation risk by producing morphological defences against predation. A classic example is the production of so-called 'neckteeth' in the water flea, Daphnia pulex, which defend against predation from Chaoborus midge larvae. Previous studies of this defence have focussed on changes in pedestal size and the number of spikes along a gradient of predation risk. Although these studies have provided a model for continuous phenotypic plasticity, they do not capture the whole-organism shape response to predation risk. In contrast, studies in fish and amphibians focus on shape as a complex, multi-faceted trait made up of different variables. In this study, we analyse how multiple aspects of shape change in D. pulex along a gradient of predation risk from Chaoborus flavicans. These changes are dominated by the neckteeth defence, but there are also changes in the size and shape of the head and the body. We detected change in specific modules of the body plan and a level of integration among modules. These results are indicative of a complex, multi-faceted response to predation and provide insight into how predation risk drives variation in shape and size at the level of the whole organism.

Assessing and improving the veracity of international trade in captive-bred animals.

Captive breeding is often seen as a solution to sustainably increasing the supply of individuals in the wildlife trade. To be an effective conservation measure this requires robust systems to verify the authenticity of captive-bred species. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) monitors the international trade in Listed species-which for many taxa is dominated by captive-bred individuals-using the Review of Captive Trade (RCT) process. A key question is how best to identify laundered or inauthentic captive-bred trade and how has this changed over time and space. We develop targeted assessments based on multiple RCT criteria to identify probable instances of laundering and misuse of source and purpose codes in international trade records, and apply this to 39,167 records of captive trade from 2000 to 2020 spanning 53,674,762 individuals. We find a very low proportion of trade volume (1.8%, 37,835 individuals) misreported as originating from non-existent, registered Appendix I-breeding facilities, and low instances of exporter-reported captive trade being recorded by importers as wild-sourced (<4%) or ranched (1%). We also find that <2% of species-year-exporter records have abrupt shifts from wild to captive sources, potentially indicating laundering. Conversely, we find high incidences of exporter- and importer-reported trade differing in whether the trade was commercial or not - a phenomenon we attribute to differing definitions, not illegal activity. Our results indicate a low incidence of concerning international trade being reported, but we suggest this likely stems from reporting requirements that limit our assessments. We highlight additional trade data that, if embedded into Party's annual reports, would vastly improve inferential potential, greatly increasing the number of records (Appendix II and III species) that could be verified with minimal effort for management authorities.

Global hotspots of traded phylogenetic and functional diversity.

Wildlife trade is a multibillion-dollar industry1 targeting a hyperdiversity of species2 and can contribute to major declines in abundance3. A key question is understanding the global hotspots of wildlife trade for phylogenetic (PD) and functional (FD) diversity, which underpin the conservation of evolutionary history4, ecological functions5 and ecosystem services benefiting humankind6. Using a global dataset of traded bird and mammal species, we identify that the highest levels of traded PD and FD are from tropical regions, where high numbers of evolutionary distinct and globally endangered species in trade occur. The standardized effect size (ses) of traded PD and FD also shows strong tropical epicentres, with additional hotspots of mammalian ses.PD in the eastern United States and ses.FD in Europe. Large-bodied, frugivorous and canopy-dwelling birds and large-bodied mammals are more likely to be traded whereas insectivorous birds and diurnally foraging mammals are less likely. Where trade drives localized extinctions3, our results suggest substantial losses of unique evolutionary lineages and functional traits, with possible cascading effects for communities and ecosystems5,7. Avoiding unsustainable exploitation and lost community integrity requires targeted conservation efforts, especially in hotspots of traded phylogenetic and functional diversity.

Association of reproductive traits with captive- versus wild-sourced birds in trade.

The wildlife trade is a billion-dollar global business, involving millions of people, thousands of species, and hundreds of millions of individual organisms. Unravelling whether trade targets reproductively distinct species and whether this preference varies between captive- and wild-sourced species is a crucial question. We used a comprehensive list of all bird species traded, trade listings and records kept in compliance with the Convention on International Trade in Endangered Species (CITES), and a suite of avian reproductive parameters to examine whether wildlife trade is associated with particular facets of life history and to examine the association between life-history traits and captive- and wild-sourced traded volumes over time. Across all trade, CITES listing, and CITES trade, large birds were more likely to be traded and listed, but their longevity and age at maturity were not associated with CITES listing or trade. We found species across almost the full range of trait values in both captive and wild trade between 2000 and 2020. Captive trade volumes clearly associated with relatively longer lived and early-maturing species; these associations remained stable and largely unchanged over time. Trait-volume associations in wild-sourced trade were more uncertain. Only body mass had a clear association, and it varied from negative to positive over time. Although reproductive traits were important in captive-sourced trade, species-level variation dominated trade, with even congeneric species varying greatly in volume despite similar traits. The collection and incorporation of trait data into sustainability assessments of captive breeding facilities are crucial to ensure accurate quotas and guard against laundering.

Asociación entre los rasgos reproductivos de aves en cautiverio versus las de origen silvestre comercializadas Resumen El mercado de fauna es un negocio mundial de miles de millones de dólares que involucra a millares de personas, miles de especies y cientos de millones de organismos individuales. Por ello es necesario resolver la cuestión de si el mercado se enfoca en especies con distinciones reproductivas y si esta preferencia varía entre las especies de origen silvestre y en cautiverio. Usamos una lista completa de todas las especies de aves comercializadas, listados y registros comerciales conforme a la Convención sobre el Comercio Internacional de Especies Amenazadas (CITES) y un conjunto de parámetros de reproducción de aves para analizar si el mercado de fauna está asociado con facetas particulares de la historia de vida. También analizamos la asociación entre los rasgos de la historia de vida y el volumen comercializado de origen silvestre y de cautiverio a lo largo del tiempo. En todos los mercados, listas de CITES y mercados CITES, las aves de mayor tamaño tuvieron mayor probabilidad de ser comercializadas y estar enlistadas, pero su longevidad y edad a la madurez no se asoció con el mercado o la lista e CITES. Detectamos especies en casi toda la gama de rasgos tanto en el comercio de cautiverio como el silvestre entre 2000 y 2020. El volumen comercial de cautiverio mostró una asociación clara con las especies relativamente más longevas y de madurez temprana; esta relación fue estable y casi no cambió con el tiempo. La asociación del volumen en las especies de origen silvestre fue más incierta; sólo la masa corporal tuvo una relación clara y ésta varió entre positiva y negativa con el tiempo. Aunque los rasgos reproductivos fueron importantes para el mercado con origen en cautiverio, la variación a nivel de especies dominó el mercado, incluso mostrando una enorme variación del volumen entre las especies congéneres a pesar de tener rasgos similares. La recolección e incorporación de datos sobre los rasgos dentro de los análisis de sustentabilidad de las instalaciones para la cría en cautiverio es crucial para asegurar las cuotas adecuadas y prevenir blanqueo de capitales.

The ecological drivers and consequences of wildlife trade.

Wildlife trade is a key driver of extinction risk, affecting at least 24% of terrestrial vertebrates. The persistent removal of species can have profound impacts on species extinction risk and selection within populations. We draw together the first review of characteristics known to drive species use - identifying species with larger body sizes, greater abundance, increased rarity or certain morphological traits valued by consumers as being particularly prevalent in trade. We then review the ecological implications of this trade-driven selection, revealing direct effects of trade on natural selection and populations for traded species, which includes selection against desirable traits. Additionally, there exists a positive feedback loop between rarity and trade and depleted populations tend to have easy human access points, which can result in species being harvested to extinction and has the potential to alter source-sink dynamics. Wider cascading ecosystem repercussions from trade-induced declines include altered seed dispersal networks, trophic cascades, long-term compositional changes in plant communities, altered forest carbon stocks, and the introduction of harmful invasive species. Because it occurs across multiple scales with diverse drivers, wildlife trade requires multi-faceted conservation actions to maintain biodiversity and ecological function, including regulatory and enforcement approaches, bottom-up and community-based interventions, captive breeding or wildlife farming, and conservation translocations and trophic rewilding. We highlight three emergent research themes at the intersection of trade and community ecology: (1) functional impacts of trade; (2) altered provisioning of ecosystem services; and (3) prevalence of trade-dispersed diseases. Outside of the primary objective that exploitation is sustainable for traded species, we must urgently incorporate consideration of the broader consequences for other species and ecosystem processes when quantifying sustainability.

Mixed protection of threatened species traded under CITES.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) regulates international legal trade to prevent the detrimental harvest of wildlife. We assess the volumes of threatened and non-threatened bird, mammal, amphibian, and reptile species in the CITES-managed trade and how this trade responded to category changes of species in the IUCN Red List between 2000 and 2018. In this period, over a thousand wild-sourced vertebrate species were commercially traded. Species of least conservation concern had the highest yearly trade volumes (excluding birds), whereas species in most Red List categories showed an overall decrease in trade reoccurrence and volume through time, with most species unlikely to reoccur in recent trade. Charismatic species with populations split-listed between Appendices I and II were traded in substantially lower yearly volumes when sourced from the more-threatened Appendix I populations. Species trade volumes did not systematically respond to changes in the Red List category, with 31.0% of species disappearing from trade before changing category and the majority of species revealing no difference in trade volumes from pre- to post-change. Just 2.7% (12/432) of species volumes declined and 2.1% (9/432) of volumes increased after a category change. Our findings highlight that non-threatened species dominate trade but reveal small numbers of highly threatened species in trade and a disconnect between species trade volumes and changing extinction risk. We highlight potential drawbacks in the current regulation of trade in listed species and urgently call for open and accessible assessments-non-detriment findings-robustly evidencing the sustainable use of threatened and non-threatened species alike.

Impacts of wildlife trade on terrestrial biodiversity.

The wildlife trade is worth billions of dollars annually and affects most major taxonomic groups. Despite this, a global understanding of the trade's impacts on species populations is lacking. We performed a quantitative meta-analysis of the wildlife trade that synthesized 506 species-level effect sizes from 31 studies, estimating trade-driven declines in mammals (452 effect sizes), birds (36) and reptiles (18). Overall, species declined in abundance by 62% (95% confidence interval (CI), 20 to 82%) where trade occurs. Reductions involving national or international trade were greatest, driving declines of 76% (95% CI, 36 to 91%) and 66% (95% CI, 12 to 87%), respectively. The impacts of trade were pervasive, requiring over 102 hours of travel time from settlements for trade to have no mean effect. Current protective measures fail species, with significant declines even where the harvesting for trade occurs in protected areas. Population declines tracked species threat status, indicating heightened extirpation and extinction risk in traded species. Critically, for such a severe global threat to wildlife, our analysis unearthed a limited number of studies using treatment versus control comparisons, and no studies on amphibians, invertebrates, cacti or orchids. Improved management, tackling both unsustainable demand and trade reporting, must be a conservation priority to prevent rampant trade-induced declines.