title: The insect central complex as model for heterochronic brain development-background, concepts, and tools.
abstract: The adult insect brain is composed of neuropils present in most taxa. However, the relative size, shape, and developmental timing differ between species. This diversity of adult insect brain morphology has been extensively described while the genetic mechanisms of brain development are studied predominantly in Drosophila melanogaster. However, it has remained enigmatic what cellular and genetic mechanisms underlie the evolution of neuropil diversity or heterochronic development. In this perspective paper, we propose a novel approach to study these questions. We suggest using genome editing to mark homologous neural cells in the fly D. melanogaster, the beetle Tribolium castaneum, and the Mediterranean field cricket Gryllus bimaculatus to investigate developmental differences leading to brain diversification. One interesting aspect is the heterochrony observed in central complex development. Ancestrally, the central complex is formed during embryogenesis (as in Gryllus) but in Drosophila, it arises during late larval and metamorphic stages. In Tribolium, it forms partially during embryogenesis. Finally, we present tools for brain research in Tribolium including 3D reconstruction and immunohistochemistry data of first instar brains and the generation of transgenic brain imaging lines. Further, we characterize reporter lines labeling the mushroom bodies and reflecting the expression of the neuroblast marker gene Tc-asense, respectively.
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.|Institute of Medical Microbiology, Otto-von-Guericke-University, Magdeburg, Germany.
authors.forename: Nikolaus Dieter Bernhard
authors.initials: ND
authors.lastname: Koniszewski
authors.affiliation: Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kollmann
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.
authors.forename: Mahdiyeh
authors.initials: M
authors.lastname: Bigham
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Farnworth
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.
authors.forename: Bicheng
authors.initials: B
authors.lastname: He
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.
authors.forename: Marita
authors.initials: M
authors.lastname: Büscher
authors.affiliation: Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.|Department of Biology, Neurobiology, University of Konstanz, Constance, Germany.
authors.forename: Wolf
authors.initials: W
authors.lastname: Hütteroth
authors.affiliation: Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.
authors.forename: Marlene
authors.initials: M
authors.lastname: Binzer
authors.affiliation: Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Schachtner
authors.affiliation: Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany. gbucher1@uni-goettingen.de.
authors.forename: Gregor
authors.identifier: 0000-0002-4615-6401
authors.initials: G
authors.lastname: Bucher
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D005075:Biological Evolution; D001921:Brain / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology; D000072669:Gene Editing / Q000379:methods*; D007313:Insecta / Q000033:anatomy & histology* / Q000145:classification / Q000254:growth & development / Q000502:physiology; D007814:Larva / Q000033:anatomy & histology; D024521:Mushroom Bodies / Q000033:anatomy & histology / Q000502:physiology; D019581:Neuropil / Q000145:classification* / Q000166:cytology; D014231:Tribolium / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development / Q000502:physiology
keywords: Brain; Central complex; Drosophila; Evolution; Heterochrony; Tribolium