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• Thomas receives his PhD

In April 2018, Thomas Théry successfully defended his doctoral dissertation. Almost a year later, his erstwhile advisor publicly celebrates the completion of his first PhD student’s studies. Entitled “Molecular systematics of the genus Essigella (Hemiptera: Sternorrhyncha)“, Thomas’s dissertation presented three published chapters.

Species of the aphid genus Essigella are found natively only in North America, feeding along the lengths of pine needles. The taxonomy of the genus was last treated by John Sorensen in 1994. He used difficult, time-consuming, but effective multi-variate morphometric methods to delineate the species. Thomas sought to corroborate or challenge Sorensen’s taxon concepts using molecular methods. In his first chapter, published in Insect Systematics and Diversity, Thomas used genes from the aphids’ nucleus, mitochondrion, and obligate nutritional symbiont Buchnera aphidicola and several molecular species delimitation methods. It was indeed a relief and a pleasure to find that, by and large, his results corroborated Sorensen’s.

Thomas did find a few additional species, however, and he proceeded to describe and name them formally in his follow-up publication in ZooKeys. Thomas’s species descriptions were innovative in that he used actual genetic nucleotide differences as diagnostic characters for his new species, something rarely done in animal taxonomy and never done before with aphids. Not to court too much controversy, Thomas made certain to include morphological diagnoses as well! The third chapter of Thomas’s dissertation was actually the first one published. We’ve already described that work on the Monterey pine needle aphid colonizing new geographic regions.

Thomas landed a full-time employment at the Insectarium of Montreal, just next door to the Biodiversity Centre, so we are pleased to see him regularly as he comes to work on his beetles at the Ouellet-Robert collection. Yes, that means that despite having worked on aphids for his PhD, we were unsuccessful at taking the histerid out of this coleopterist. We’re proud of you anyway, Dr Théry, congratulations!

Thomas and his thesis defence jury: Chris Cameron, Liliana Perez, Luc Brouillet, Colin, and Jade Savage.

Théry T, Kanturski M, Favret C. 2018. Molecular phylogenetic analysis and species delimitation in the pine needle-feeding aphid genus Essigella(Hemiptera, Sternorrhyncha, Aphididae). Insect Systematics and Diversity, 2(4):1;1-15. DOI: 10.1093/isd/ixy006

Théry T, Kanturski M, Favret C. 2018. Molecular data and species diagnosis in Essigella Del Guercio, 1909 (Sternorrhyncha, Aphididae, Lachninae). ZooKeys, 765: 103-122. DOI: 10.3897/zookeys.765.24144

Théry T, Brockerhoff EG, Carnegie AJ, Chen Rui, Elms SR, Hullé M, Glatz R, Ortego J, Qiao Gexia, Turpeau É, Favret C. 2017. EF-1α DNA sequences indicate multiple origins of introduced populations of Essigella californica(Hemiptera, Aphididae). Journal of Economic Entomology, 110(3): 1269-1274. DOI: 10.1093/jee/tox026