Thomas Blankers

Post-doctoral research fellow at the University of Amsterdam

General description

I am interested in speciation and in the evolutionary forces governing diversity in the animal kingdom. The diversity of life on earth is not only fascinating, it is also central to our existence. Diversity between species maintained by barriers to gene flow is important to local biological communities. Diversity within species is the source of variation needed for new species to evolve and for existing species to cope with inevitable changes in their environment. Diversity is the result of complex eco-evolutionary interactions between organisms and their biotic and abiotic environment, between females and males, and between hosts and their symbionts. I study invertebrate species using behavioral, quantitative genetic, and genomic approaches to understand the forces that drive the speciation and how they interact to shape biological diversity. Below is a brief summary of my research vignettes. 

Host-microbiome co-evolution

An emerging insight is that the ecology and evolution of many multicellular eukaryotes is determined in part by the microbiota that live inside their cells and in their intestinal tract. I am particularly interested in the contribution of microbial communities to adaptation and speciation in their hosts and vice versa. I therefore study the co-evolution (or lack thereof) between host and microbes in the sexually isolated but ecologically cryptic Laupala crickets and in experimental evolution lines of the nematode C. elegans.

Predicting evolution

I am currently appointed as a research fellow in the recently established Origins Center , which is one of the NWA routes . In this ambitious multidisciplinary research center, we try to answer fundamental questions about the origin of life on earth and in the universe combining insights from chemistry, (astro)physics, and biology. I am part of a team of evolutionary biologists that works on the predictability of evolution. Specifically, we have evolved the nematode Caenorhabditis elegans for 15 generations on a novel food source. This evolutionary experiment has been repeated many times across seven participating labs in The Netherlands. Using the data on the changes in fitness, morphology, and genetics through time, we are probing the predictability of evolution and also keep track of several environmental factors that may influence the extent to which we can predict evolutionary responses.

The genetic basis of pheromone communication in noctuid moths  

In the animal kingdom, sexual signals are highly variable among species. Sexual signal divergence is an important reproductive barrier between species, because males and females typically only mate when they are reciprocally attracted to each other’s signals. It is therefore important to understand how sexual signals evolve and how they contribute to genetic barriers that maintain species diversity. Moreover, in the most damaging group of insect pests, the Heliothine moths, sexual signals are an important target for sustainable pest management. In moths, the female emits a long-distance pheromone signal as she calls for male mates. Sex pheromones are species-specific blends of various chemical components. Like most signals, they consist of multiple traits and can evolve in multiple directions. Furthermore, the evolution of one such pheromone component is not independent of the evolution of other components, because they are often biochemically and genetically linked. In this project I studied the genetic architecture of the evolution of moth sex pheromones. This project combines research on pheromone signal – life history trade-offs, experimental evolution, and mapping of the genetic loci underlying experimental evolution responses to understand the mechanisms that contribute to variation in the female sex pheromone in the moth Heliothis subflexa.. 

The evolutionary and population genetics of a rapid island radiation of flightless crickets

I worked at Cornell University from Aug 2016 – Aug 2018 in Kerry Shaw’s lab on the evolutionary genetics of Laupala cricket diversity. Laupala is a species-rich (38 described species) genus of flightless swordtail crickets endemic to the Hawaiian archipelago. The group has among the highest speciation rates in animals (the youngest island, Hawaii, is less than half a million years old and home to seven endemic species!) and is therefore of premier interest to speciation genetics. This project involves two major parts: (i) the genetic architecture of divergence in male song rhythm (pulse rate) across several species of Hawaiian swordtail crickets (Laupala) and (ii) population genomics in a genetically and geographically highly variable species, Laupala cerasina. The first part consists of a series of linkage mapping and QTL studies which have largely been published (publications 12 and 13 in my list of publications, one additional study in preparation). The second part is still work in progress and will consist of a study on population structure, evolutionary history, and genome-wide analysis of genetic divergence as well as an analysis of variation in the cricket-associated gut microbiome.

Acoustic communication, sexual selection, and speciation in field crickets (PhD thesis, Humboldt University / Naturkundemuseum Berlin – supervision: R. Matthias Hennig, Frieder Mayer, co-authors: David A. Gray, Emma Berdan)

My PhD project in Berlin was focused on acoustic mate choice behavior in North American field crickets and the patterns of genetic variation during speciation with gene flow. My thesis integrates insights from neuro-ethological, behavioural, quantitative genetics, and genomic approaches in field crickets to provide novel insights in the role of sexual selection in speciation. We provided detailed descriptions of female preference functions, their effect on male signal evolution, and patterns of diversification among females of different species (pubs 3 & 5). We also explored the integration of signal and preference traits by analyzing species differences in a multivariate framework (pubs 4 & 9) and also by means of a QTL study that looks at the genetic architecture of male signal traits, female preference, and the architecture of gene expression related to those traits (in preparation). Lastly, we performed a detailed analysis of the genetic evolution in two closely related species, Gryllus rubens and G. texensis, to elucidate the role of neutral genetic divergence and sexual selection during speciation with gene flow (10).

Adaptive radiation and ecomorphology of lizards and salamanders (MSc research, Stony Brook University, NY – supervision: John J. Wiens, Steph B. Menken)

During my MSc at the University of Amsterdam, I visited the Wiens’ lab at Stony Brook University for a research project on the ecomorphology of salamanders and lizards. Using comparative phylogenetic methods, we explored two large clades, the plethodontid salamanders and the iguanian lizards, for relationships between morphology and microhabitat use as well as for general phylogenetic patterns of diversification (pubs 1 & 2).