Biology subjects

Melika, G.

Publications and source records attributed to Melika, G..

2 recordsLinked to original sources

bioRxiv2024

Phylogenetic and non-phylogenetic patterns in the richness, frequency and composition of links in a herbivore-parasitoid interaction network

Revealing processes that structure species interactions is central to understanding community assembly and dynamics. Species interact via their phenotypes, but identifying and quantifying the traits that structure species-specific interactions (links) can be challenging. Where these traits show phylogenetic signal, however, link properties may be predictable using models that incorporate phylogenies in place of trait data. We analysed variation in link richness, frequency, and species identity in a multi-site dataset of interactions between oak cynipid galls and parasitoid natural enemies, using a Bayesian mixed modelling framework allowing concurrent fitting of phylogenetic effects of both trophic levels. In both link incidence (presence/absence) and link frequency datasets, we identified strong signatures of cophylogeny (related parasitoids attack related host galls) alongside patterns independent of either phylogeny. Our results are robust to simulations of substantially reduced sample completeness, and are consistent with the structuring of trophic interactions by a combination of phylogenetically conserved and convergently evolving traits in both trophic levels. We discuss our results in light of phenotypic traits thought to structure gall-parasitoid interactions and consider wider applications of this approach, including inference of underlying community assembly processes and prediction of economically important trophic interactions.

ecology↗

bioRxiv2022

Delimiting the cryptic diversity and host preferences of Sycophila parasitoid wasps associated with oak galls using phylogenomic data

Cryptic species diversity is a major challenge for the species-rich community of parasitoids attacking oak gall wasps due to a high degree of sexual dimorphism, morphological plasticity, small size, and poorly known biology. As such, we know very little about the number of species present, nor the evolutionary forces responsible for generating this diversity. One hypothesis is that trait diversity in the gall wasps, including the morphology of the galls they induce, has evolved in response to selection imposed by the parasitoid community, with reciprocal selection driving diversification of the parasitoids. Using a rare, continental-scale data set of Sycophila parasitoid wasps reared from 44 species of cynipid galls from 18 species of oak across the US, we combined mitochondrial DNA barcodes, Ultraconserved Elements (UCEs), morphological, and natural history data to delimit putative species. Using these results, we generate the first large-scale assessment of ecological specialization and host association in this species-rich group, with implications for evolutionary ecology and biocontrol. We find most Sycophila target specific subsets of available cynipid host galls with similar morphologies, and generally attack larger galls. Our results suggest that parasitoid wasps such as Sycophila have adaptations allowing them to exploit particular host trait combinations, while hosts with contrasting traits are resistant to attack. These findings support the tritrophic niche concept for the structuring of plant-herbivore-parasitoid communities.

evolutionary biology↗