Curry, T. R. | bioRxiv Science

bioRxiv2026

Mite Genome Miniaturization: Assembly of the biological control agent Floracarus perrepae reveals dynamic genome evolution in eriophyoid mites

The eriophyoid mites (Acari: Eriophyoidea) represent an extreme case of genome streamlining, with genomes averaging just 32Mb, among the smallest of all animals. This clade of mites is highly diverse with more than 4000 species. Their morphologies are specialized for feeding on their host plants, including a simplified worm-like body plan with just two pairs of legs and modified mouth parts that can induce the formation of galls or plant deformities during feeding. Their generally strong host affinities make eriophyoid mites appealing for use as biological control agents, although their short generation times and small genomes could facilitate rapid evolution and impact their efficacy in management programs. Here, we sequenced the genome of the biological control mite Floracarus perrepae, producing a highly contiguous genome totalling just 23.1 Mb, among the smallest of all animals. We also assembled another non-eriophyid mite genome from accidental DNA bycatch (69.4Mb). We placed this new genomic resource in a phylogenetic context to reveal that mites have highly dynamic genome evolution, with a significant trend in genome downsizing in the eriophyoids. Our results suggest that this streamlining is associated with non-genic elements such as the suppression or excision of retrotransposons and purging of introns. As new sequencing techniques become available, novel genomic resources for tiny organisms such as F. perrepae will be more readily accessible, facilitating both fundamental genome evolutionary biology and applied sciences such as biological control programs which use eriophyoid mites for the management of invasive species.

evolutionary biology↗

bioRxiv2025

Near chromosome-level genome assembly of Neomusotima conspurcatalis gives insights into the evolution of moth genome architecture and fern-insect interactions

Plant-insect interactions are the foundation of ecosystems globally, yet we are still determining the underlying mechanisms through which these relationships evolve. The co-evolution between insects and their host plants should shape the genomes of both partners, and genes involved in interaction specificity should show unique genomic signatures (e.g., rapid evolution, gene family expansions). Biological control programs are an excellent system for disentangling the genomics and molecular biology of the establishment of an insect and its host plant specificity. Fern-insect relationships are among the most poorly understood, and ferns have long been thought to have few interactions with insects, although recent evidence suggests that these relationships are under-sampled and studied. Here, we present a near-chromosome genome assembly of the crambid moth Neomusotima conspurcatalis, a biological control agent employed in the management of the invasive vining fern Lygodium microphyllum. We use this novel genomic resource to explore the evolution of genome architecture across the Crambidae, revealing highly conserved genome structure across this family of moths. We also examine gene family evolution across the phylogeny and identify expansions in odorant receptor gene families that may be involved in the highly specific interaction of N. conspurcatalis with L. microphyllum. This work highlights the utility of genomics in biological control, and the utility of biological control in informing fundamental understanding of plant-insect interactions. SummaryPlant-insect interactions form the basis of ecological communities and can be highly specific through long lasting co-evolution. Classical biological control provides excellent opportunities to investigate how insect and host genomes are shaped by co-evolutionary processes. We sequenced the genome of Neomusotima conspurcatalis, a biological control moth used to manage the invasive fern Lygodium microphyllum. We analyzed how the structure of the genome has evolved over time relative to other crambid moths and how expansions in gene families involved in odorant reception may be involved in co-evolution with its host. This work provides insight into herbivore interactions in seed-free vascular plants.

evolutionary biology↗