Combining 3D models, image analyses and gene expression data to study eye development in the malaria mosquito, Anopheles gambiae

Combining 3D models, image analyses and gene expression data to study eye development in the malaria mosquito, Anopheles gambiae Matthew Quinn1, Vivek Nityananda3, Chieko Itakura1, Maike Kittelmann2 Olena Riabinina1 1 Department of Biosciences, Durham University, Durham, DH1 3LE, UK 2 Oxford Brookes University, Oxford, OX3 0BP, UK 3 Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne, NE2 4HH, UK Stemmata are larval eyes found uniquely in Holometabolous insects such as flies, butterflies and beetles (Friedrich, 2003). Work on Aedes aegypti mosquitoes indicated that larvae possess both the larval and the developing adult eyes, and both are functional in the later stages of larval development (Mysore et al., 2014). Opsins are G-protein coupled receptors that determine the sensitivity of an insect to different wavelengths of light (Brody & Cravchik, 2000). Larval and adult eyes are predicted to express different types of opsin genes in Aedes aegypti (Rocha et al., 2015). However, this has not been proven in Anopheles gambiae. In Drosophila melanogaster, only 4 larval photoreceptors survive metamorphosis as they are recycled into the adult eye during pupation (Helfrich-Förster et al., 2002). We aim to characterize expression of opsin genes throughout the stages of development alongside the anatomy of the larval visual system. We acquired synchrotron data to visualise the anatomy by creating 3D models of the larval visual system. We show that not only Anopheles gambiae possess both the larval and adult eye that are present at the same time later in development, but the innervation of both eyes forms a single optic nerve as previously seen in Aedes aegypti larvae (Mysore et al., 2014). We demonstrate that while the adult eye and optic lobes get continue to develop, the larval eye gets smaller not only in size but also the expression of a larval specific gene opsin 6, is also reduced later in development.