DOI: 10.5061/dryad.1vhhmgr1z
title: Morphology and ultrastructure of external sense organs of Drosophila larvae

description: Sensory perception is the ability through which an organism is able to
 process sensory stimuli from the environment. This stimulus is transmitted
 from the peripheral sensory organs to the central nervous system, where it
 is interpreted. Drosophila melanogaster larvae possess peripheral sense
 organs on their head, thoracic, and abdominal segments. These are
 specialized to receive diverse environmental information, such as
 olfactory, gustatory, temperature, or mechanosensory signals. In this
 work, we complete the description of the morphology of external larval
 sensilla and provide a comprehensive map of the ultrastructure of the
 different types of sensilla that comprise them. This was achieved by 3D
 electron microscopic analysis of partial and whole body volumes, which
 contain high-resolution and complete three-dimensional data of the anatomy
 of the sensilla and adjacent ganglia. Our analysis revealed three main
 types of sensilla on thoracic and abdominal segments: the papilla
 sensillum, the hair sensillum, and the knob sensillum. They occur solitary
 or organized in compound sensilla such as the thoracic keilin’s organ or
 the terminal sensory cones. We present a spatial map defining these
 sensilla by their position on thoracic and abdominal segments. Further, we
 identify and name the sensilla at the larval head and the last fused
 abdominal segments. We show that mechanosensation dominates in the larval
 peripheral nervous system, as most sensilla have corresponding structural
 properties. The result of this work, the construction of a complete
 structural and neuronal map of the external larval sensilla, provides the
 basis for following molecular and functional studies to understand which
 sensory strategies the Drosophila larva employs to orient itself in its
 natural environment.
description: Data collection was focused on Ion-Beam electron microscopy with
 minimal embedding technique (see manuscript material and
 methods).
description: # Morphology and ultrastructure of external sense organs of Drosophila
 larvae
 [https://doi.org/10.5061/dryad.1vhhmgr1z](https://doi.org/10.5061/dryad.1vhhmgr1z) This is a collection of focus ion-beam SEM datasets of the external sense organs of Drosophila larvae. The specimens used were third-instar wildtype Canton-S larvae. ## Description of the data and file structure In the Zip folder 'EM_data_zipped', there are two main folders, one with the focused Ion-Beam scanning electron microscopy (**FIB-SEM**) data and the other one with the scanning electron microscopy (**SEM**) data of the outer morphology of the different sensilla. Each main folder contains subfolders for the sensilla investigated in this work. For each sense organ or sensillum type, there are one or more FIB-SEM volumes. Furthermore, for each sensillum, there is at least one SEM image for the outer morphology. For metadata, open file in Fiji or text editor --&gt; FOV_X units is the width of the image in um. FOV_Y units are the height of the image in um. Z-steps are indicated in the file description.