Borowski, Z. | Search bioRxiv

bioRxiv2023

Complex genomic landscape of inversion polymorphism in Europe's most destructive forest pest

In many species, polymorphic inversions underlie complex phenotypic polymorphisms and facilitate local adaptation in the face of gene flow. Multiple polymorphic inversions can co-occur in a genome, but the prevalence, evolutionary significance, and limits to complexity of genomic inversion landscapes remain poorly understood. Here, we examine genome-wide variation in one of Europes most destructive forest pests, the spruce bark beetle Ips typographus, scan for polymorphic inversions, and test whether inversions are involved in key adaptations in this species. We analyzed 240 individuals from 18 populations across the species European range and, using a whole-genome resequencing approach, identified 27 polymorphic inversions covering approximately 28% of the genome. The inversions vary in size and in levels of intra-inversion recombination, are highly polymorphic across the species range, and often overlap, forming a complex genomic architecture. We test several mechanisms, including directional selection, overdominance and associative overdominance that can contribute to the maintenance of inversion polymorphisms in the genome. We show that the heterogeneous inversion landscape is likely maintained by the combined action of several evolutionary forces and that inversions are enriched in odorant receptor genes encoding key elements of recognition pathways for host plants, mates, and symbiotic fungi. Our results indicate that the genome of this major forest pest of growing social, political, and economic importance harbors one of the most complex inversion landscapes described to date posing a question about limits of genomic architecture complexity.

evolutionary biology↗

bioRxiv2023

Performance and allocation can simultaneously shape behaviour in fire-disturbed populations of root vole

Metabolic physiology and animal personality are often considered linked to each other, shaping ecological and evolutionary strategies along a life-history continuum. The energy allocation model predicts a negative while the performance model predicts a positive correlation between the rate of metabolic processes and behaviours, such as activity level. The models might operate simultaneously but depending on the context one can predominate over the other, determining expression of alternative pro- and reactive behavioural strategies. Large-scale fires, such as the one that burnt wetlands of Biebrza National Park (NE Poland), degrade natural habitats, affect amount of food and shelters and modify predatory-prey interactions. Fires pose also direct threat to survival of local populations, such as the wetland specialist root vole (Microtus oeconomus). We hypothesized that fire disturbance, by changing environmental context and selective regimes, determines mechanisms linking physiology and behaviour. Positive relation found among most studies, predicted by the performance model, would revert to negative relation, predicted by the allocation model, affecting animals ecological strategy in disturbed habitat. We repeatedly measured maintenance and exercise metabolic rates and activity behaviour on voles from post-fire and unburnt populations. Repeatable maintenance metabolism and activity level were positively correlated, but more labile exercise metabolism did not explain behaviour. The correlations were not strongly affected by fire disturbance, but voles from post-fire habitat had higher maintenance but not maximum metabolism and moved shorter distances than individuals from unburnt area. The results suggest that performance model predominates, while habitat disturbance might reveal some allocation constraints on physiology-personality linkage. Summary statementContrasting allocation and performance models, for energetics-behaviour linkage, were tested in context of fire-disturbance. Positive (performance) correlation predominated but animals from burned habitat had elevated metabolism and suppressed exploration (allocation).

zoology↗