# Genomic and transcriptomic analyses of Heteropoda venatoria reveal the expansion of P450 family for starvation resistance in spiders

## TL;DR

This study explores how Heteropoda venatoria spiders resist starvation by analyzing their genome and gene expression patterns, revealing expanded P450 genes that help them survive long periods without food.

## Contribution

The study identifies the expansion of P450 gene families in H. venatoria and their role in starvation resistance, offering new insights into spider and arthropod adaptation.

## Key findings

- H. venatoria relies on glucose metabolism early in starvation and shifts to fatty acid metabolism and autophagy in later stages.
- Expanded CYP3 clan P450 genes are highly expressed in the fat body, potentially supporting low-energy metabolism.
- P450 motifs in H. venatoria are less conserved than in insects, suggesting greater genomic polymorphism in spiders.

## Abstract

Research on the mechanism of starvation resistance can help reveal how animals adjust their physiology and behavior to adapt to the uncertainty of food resources. A low metabolic rate is a significant characteristic of spider physiological activity and can increase spider starvation resistance and adapt to complex ecological environments.

We sequenced the genome of Heteropoda venatoria and discovered significant expansions in gene families related to lipid metabolism, such as cytochrome P450 and steroid hormone biosynthesis genes, through comparative genomic analysis. We also systematically analyzed the gene expression characteristics of H. venatoria at different starvation resistance stages and reported that the fat body plays a crucial role during starvation in spiders. This study indicates that during the early stages of starvation, H. venatoria relies on glucose metabolism to meet its energy demands. In the middle stage, gene expression stabilizes, whereas in the late stage of starvation, pathways for fatty acid metabolism and protein degradation are significantly activated, and autophagy is increased, serving as a survival strategy under extreme starvation. Notably, analysis of expanded P450 gene families revealed that H. venatoria has many duplicated CYP3 clan genes that are highly expressed in the fat body, which may help maintain a low-energy metabolic state, allowing H. venatoria to endure longer periods of starvation. We also observed that the motifs of P450 families in H. venatoria are less conserved than those in insects are, which may be related to the greater polymorphism of spider genomes.

This research not only provides important genetic and transcriptomic evidence for understanding the starvation mechanisms of spiders but also offers new insights into the adaptive evolution of arthropods.