Song, Y.-F. | bioRxiv Science

bioRxiv2026

Conservation Blind Spot: The Critical Role of Larval Stage in Assessing Extinction Risk

In an era of severe global biodiversity threats, understanding the link between species traits and their endangerment helps uncover causes of risk and infer threats to understudied species. Most animals have complex life cycles with distinct stages that may face stage-specific threats. Current conservation frameworks rely heavily on adult traits, potentially misjudging extinction risk. Using Chinese anurans as a model, we integrated functional traits from both adult and tadpole stages to examine their association with extinction risk. We found that body size positively correlates with risk in both stages. Microhabitat use related with extinction risk in tadpoles but shows no significant link in adults. Adult relative tympanum diameter and head length also correlate with extinction risk. These results indicate that species vulnerability is correlated with multi-stage traits, with both shared and stage-specific threats. Conservation based solely on adult traits may fail to accurately assess species threats. We call for integrating a whole-life-history perspective into biodiversity assessment and conservation to more effectively address the global biodiversity crisis.

ecology↗

bioRxiv2025

Uncovering the Genetic Basis of Heterodichogamy in Pterocarya and Cyclocarya Using a Low-Input Pan-Genomic Approach

The heterodichogamous mating system, characterized by two distinct mating types (protogyny and protandry), is rare among flowering plants, but it is present in nearly all species in Juglandaceae (the walnut family). Recent studies have identified distinct structural variations underlying heterodichogamy in Juglans and Carya. To verify the independent origins of this trait in Juglandaceae and investigate whether structural variations also drive heterodichogamy in Juglans closely related genera, we explored its genetic basis in Pterocarya and Cyclocarya. Using a pan-genome graph approach, we identified a structural variation region associated with mating types across the Pterocarya genus. This region includes 30 kb tandem repeats in the dominant allele and an insertion in the recessive allele, with shared polymorphisms spanning 78 kb from the 3'UTR of S12e, covering a FAF-like gene, to a Gypsy transposable element. Downstream analyses suggest that the specific expression of FAF-like gene and small RNAs uniquely expressed from the tandem repeats of dominant allele regulate heterodichogamy. Further investigation in Cyclocarya identified nine candidate loci associated with heterodichogamy, which are non-homologous regions with those found in Pterocarya, Juglans, and Carya. These findings provide novel evidence for the multiple independent originations of convergent genetic basis in regulating heterodichogamy in Juglandaceae and highlight the utility of pan-genome approaches in deciphering structural variation-associated traits.

evolutionary biology↗