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FRIMEDBIO-Fri prosj.st. med.,helse,biol

A PHYLOGENOMIC APPROACH TO UNDERSTAND THE DIVERSIFICATION OF BARK BEETLES AND ASSOCIATED MICROBES

Awarded: NOK 2.7 mill.

Project Number:

214232

Application Type:

Project Period:

2012 - 2016

Partner countries:

The main aim of the project is to establish a robust phylogeny for about 200 species of bark and ambrosia beetles. Tree topologies are now used in comparative analyses on host plant use and association with symbiotic fungi in such beetles. We have establishing 50 molecular markers, of which 18 have sufficient quality for phylogenetic analysis at this level. We are now at a stage where sequence data are analysed three manuscripts are in progress. The first one is dealing with 13 markers new to insect systematics. Communities of fungi are screened in the Hulcr laboratory (U.FL) where a new procedure is established that uses 454-sequencing of entire communities associated with individual beetles. Results for three closely related beetle species are published. Further work include screening for fungal communities across a larger variety of beetle lineages, to be completed November 2015. The comparative studies are initiated and the first paper is now submitted (methods: on missing taxa in diversification studies). Further results include identification of beetles collected in the field (Madagascar trip 2 and Angola); some of these are included in the final phylogenetic analyses. Smaller phylogenetic studies have also been published, including phylogenies ion Platypodinae and Micracidini and close relatives. The project has established further collaboration with U. Mississippi and U. Florida on utilizing sequence capture data from 500 ultra conserved elements.

Bark and ambrosia beetles are a remarkably diverse group of weevils with extraordinary variation in ecological adaptations. As one of the most species rich subfamilies among the advanced weevils, they dominate any forest insect community around the globe. While the most famous features of these beetles are vast outbreaks and damage to timber and other forest products, coordinated tree killing is only one of many kinds of unusual lifestyles. The colonization and reproduction in concealed niches in dead woo dy plant tissue has for instance led to multiple origins of fungus farming, sometimes with modifications of mating systems to allow close inbreeding by sibling mating, which likely facilitated multiple super-radiations similar to those observed for pine a nd spruce associated bark beetles. However, knowledge about the timing and ecological circumstances under which each of the largest radiations originated is highly uncertain, due to the lack of phylogenetic resolution for this beetle group. Establishing a n accurate phylogenetic hypothesis is therefore of paramount importance in enabling detailed inference about these great radiations. Resolution of hyperdiverse groups is a daunting task, however, and only a large scale phylogenomic approach can provide su fficient data to enable reconstruction of evolutionary transitions at different hierarchical levels. Comparative analyses of transitions to fungus farming are dependent on detailed data on communities of symbiotic fungal microbes. We will therefore carry out the first quantitative inference of the evolution of a symbiosis between beetles and communities of fungi, to demonstrate the composition of different fungal species associated with a single beetle, and the variation in community composition across di fferent groups of beetles. Our novel approach thus makes a ground-breaking example for quantitative studies on the evolution of diverse symbioses, particularly so in light of interaction with vascular host plants.

Publications from Cristin

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Funding scheme:

FRIMEDBIO-Fri prosj.st. med.,helse,biol

Funding Sources