Brock, R. E. | Search bioRxiv

bioRxiv2026

Larval antibiosis to cabbage stem flea beetle (Psylliodes chrysocephala) is absent within oilseed rape (Brassica napus)

BACKGROUNDInsect pests present a global threat to crops, with plant resistance representing a key breeding goal. The cabbage stem flea beetle (Psylliodes chrysocephala; CSFB) is a key pest of oilseed rape (Brassica napus; OSR) within Europe; however, CSFB resistance is yet to be found within B. napus. To address this, we examine CSFB larval development over time, explore antibiosis across a genetically diverse B. napus panel, and test whether larvae can develop within model Brassicaceae species (Brassica rapa and Arabidopsis thaliana). RESULTSCSFB larvae completed development from four-weeks post-infestation, undergoing a 20-fold size increase, with larval recovery after two weeks allowing semi-high throughput resistance phenotyping. Applying this method to 98 Brassicaceae genotypes (97 B. napus and a single Sinapis alba), we found weak evidence for genotype effects on larval survival. However, phenotype validation with resistant and susceptible B. napus genotypes showed no differences in larval survival or adult emergence. Larval antibiosis was consistently observed in S. alba. Finally, we showed that model B. rapa and A. thaliana genotypes represent suitable hosts for CSFB, with larvae increasing 8-10x in size after two weeks. CONCLUSIONCSFB larval antibiosis appears absent within B. napus, possibly due to bottlenecks experienced during domestication. However, larval antibiosis is present within S. alba, and future work should study the basis of this resistance. Further, CSFB larval screening in Brassicaceae model species presents an opportunity to explore CSFB resistance genetics, informing breeding progress for insect resistance in B. napus.

plant biology↗

bioRxiv2020

Genetic toolkit for sociality predicts castes across the spectrum of social complexity in wasps

Major evolutionary transitions describe how biological complexity arises; e.g. in evolution of complex multicellular bodies, and superorganismal insect societies. Such transitions involve the evolution of division of labour, e.g. as queen and worker castes in insect societies. Castes across different evolutionary lineages are thought to be regulated by a conserved genetic toolkit. However, this hypothesis has not been tested thoroughly across the complexity spectrum of the major transition. Here we reveal, using machine learning analyses of brain transcription, evidence of a shared genetic toolkit across the spectrum of social complexity in Vespid wasps. Whilst molecular processes underpinning the simpler societies (which likely represent the origins of social living) are conserved throughout the major transition, additional processes appear to come into play in more complex societies. Such fundamental shifts in regulatory processes with complexity may typify other major evolutionary transitions, such as the evolution of multicellularity.

evolutionary biology↗