Symbioses with microorganisms have dramatically influenced the biology and evolution of eukaryotes. Symbionts have enabled the emergence and enabled the evolutionary success of major host clades and shaped their interactions with other organisms and the environment. In the rapidly changing world that we live in, there is little doubt that symbiotic microbes will continue having major, and perhaps increasing, effects on host populations and communities, and on their abilities to deal with the environmental challenges.

The goal of our new research group will be to understand the broad patterns of the microbial diversity across insects, the most diverse and ecologically important class of animals, and the dynamics of the insect microbiomes across space and time. How variable are the microbiota among individuals, populations, species, and larger clades? How does this vary across seasons, years, and at geological timescales? And how do these microbes affect host biology?

We will address these questions through high-throughput next-generation sequencing of microbiota across large numbers of individual insects, carefully selected from larger, well-curated specimen collections, and through bioinformatic analyses of the resulting data. We will focus our efforts on two projects, using similar methods but concentrating on different groups of insects and on very different temporal scales.

Are you interested in discussing, collaborating, or joining in either of these projects? If so, get in touch!

1. The evolution of obligate symbioses in the hemipteran suborder Auchenorrhyncha

Insects from the suborder Auchenorrhyncha, comprising cicadas, spittlebugs, leafhoppers, treehoppers, and planthoppers, host some of the most specialized known microbial endosymbionts. These microbes produce essential amino acids and vitamins deficient in the hosts’ diet of plant sap and are therefore strictly necessary to the insects. The symbionts have been reliably transmitted from mothers to offspring, for a very long time – as much as 300 million years in some cases. But in many lineages of Auchenorrhyncha, the ancient symbionts have became replaced or complemented by other microorganisms.

Our goal is to understand the nature, incidence, and consequences of these replacements, the origins, functions and the genome evolutionary patterns of the replacing microbes, and the consequences of the replacements for the insect hosts.

We will conduct next generation sequencing-based surveys of symbiotic microbes in an extensive collection of Auchenorrhyncha from around the world, followed by detailed phylogenomic and comparative genomic analyses of host and symbiont data. This collaborative work, expanding upon my postdoctoral research on symbioses in one of Auchenorrhynchan clades (cicadas), will result in a thorough description of evolutionary processes related to eukaryotic symbioses: infection, co-diversification, genome reduction, and replacement. It will also provide vast amount of information on other aspects of biology of this significant insect clade.

This work is supported by a grant from Polish National Science Centre (NCN) “The evolutionary dynamics of the symbioses of Auchenorrhynncha” no. 2018/30/E/NZ8/00880 (Sonata Bis 8 program, 2019-2024)

    Want to know more? Check out my colleagues’ and my recent papers:

Bennett G.M. & Moran N.A. (2015): Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole. – PNAS 112(33): 10169-10176
Łukasik P., Nazario K., Van Leuven J.T., et al. (2018): Multiple origins of interdependent endosymbiotic complexes in a genus of cicadas. – PNAS 115(2): E226-E235
Matsuura Y., Moriyama M., Łukasik P., et al. (2018) Recurrent symbiont recruitment from fungal parasites in cicadas. – PNAS 115(26): E5970-E5979

Auchenorrhyncha harbor their nutritional endosymbionts within a dedicated organ called bacteriome. Fluorescent microscopy shows that the ancient symbionts, including Sulcia and Hodgkinia of cicadas, occupy well-defined places inside cells that form the bacteriome. But following the symbiont replacement, things can get much more complicated! 

The diversity of treehopper body shapes. We know much less about the diversity of their symbionts! Image: Matthew A. Bertone, based on plates by Edwin Wilson from Biologia Centrali-Americana (1894-1896)

2: The ecological and evolutionary dynamics of insect symbioses

Our knowledge of the diversity and distribution of symbiotic microorganisms across insects is fragmentary, especially outside of model species. Consequently, we know little about how variable microbiomes are within host species, and what environmental and biological factors influence the abundance and composition of microbial symbionta. To address this gap, our group will apply cutting-edge next-generation sequencing methods to large batches of taxonomically diverse insects collected across time and space.

We will collaborate closely with a massive insect biodiversity project, Insect Biome Atlas, which conducts large-scale sampling of flying insect communities across Sweden and Madagascar. We are also starting long-term insect community sampling in Greenland. These collections will serve as a source of vast numbers of insect specimens for high-throughput microbiome screens, followed by more detailed genomics investigation of selected symbiotic associations. The resulting data will provide information on the symbiont distribution at multiple levels: across the host phylogeny, geography, and time. They will also inform us of the mobility of symbionts within and across species, the predominant routes of interspecific symbiont transmission, and of the symbionts’ biological roles.

Insect Biome Atlas (IBA), a long-term international project with headquarters at the Swedish Museum of Natural History, aims to comprehensively characterize factors that shape insect community composition. Thousands of insect community samples provided by IBA, comprising tens of millions of individuals, will be an invaluable source of material for our research.

This work is supported by grants from the Polish National Agency for Academic Exchange (NAWA) “Insect Microbiomics” no. PPN/PPO/2018/1/00015 (Polish Returns 2018 program, 2019-2023), from Polish National Science Centre (NCN) “Insect microbiome dynamics in time and space” no. 2018/31/B/NZ8/01158 (Opus 16 program, 2019-2022), and by international collaborators’ funds, including the large Wallenberg Foundation grant (Sweden) that has enabled the Insect Biome Atlas project.