Morphological characterization of the antennal lobes in the Mediterranean fruit fly Ceratitis capitata

Abstract

The medfly Ceratitis capitata is one of the most important pests for horticulture worldwide. The knowledge about anatomy and function of the medfly olfactory system is still limited. The first brain structure to process olfactory information in insects is the antennal lobe (AL), which is composed of its functional and morphological units, the olfactory glomeruli. Here, we present a morphological three-dimensional reconstruction of AL glomeruli in adult brains. We used unilateral antennal backfills of olfactory receptor neurons (ORNs) with neural tracers, revealing the AL structure. We recorded confocal stacks acquired from whole-mount specimens, and analyzed them with the software AMIRA. The ALs in C. capitata are organized in glomeruli which are more tightly packed in the anterior part than the posterior one. Axons of ORNs bilaterally connect the ALs through a commissure between the two ALs. This commissure is formed by several distinct fascicles. Contralateral dye transfer suggests the presence of gap junctions connecting ORNs from both antennae. There was no statistical difference between the average volumes of female ALs (204,166 ± 12,554 μm(3)) and of male ALs (190,287 ± 11,823 μm(3)). In most specimens, we counted 53 glomeruli in each AL, seven of which were sexually dimorphic in size

Octopamine modulates the activity of motoneurons related to calling behavior in the gypsy moth Lymantria dispar

“…To identify and localize the neurons projecting into the nerve pairs IV-VI of the TAG, backfills were performed, in three to four specimens, from the respective nerve stumps with a tetramethylrhodamine-conjugated dextran amine (TMR-DA) combined with laser scanning confocal microscopy (LSCM), according to Solari et al (2016).…”

Glomerular Organization in the Antennal Lobe of the Oriental Fruit Fly Bactrocera dorsalis

“…The procedure used for identifying the individual glomeruli was similar to that used by Solari et al ( 2016 ). For clarity, we divided the AL into six regions, i.e., anterior (A), dorsal (D), ventral (V), Central (C), lateral (L), and medial (M).…”

“…Identification of glomeruli in the B. dorsalis ALs was based on their location, size and shape. The nomenclature used in this followed that for Ceratitis capitate (Solari et al, 2016 ) and Drosophila melanogaster (Stocker et al, 1990 ). Based on general position, the names of glomeruli start with one or two capital letters (A, anterior; P, posterior; D, dorsal; V, ventral; L, lateral; M, medial; C, central).…”

Association between olfactory sensitivity and behavioral responses of Drosophila suzukii to naturally occurring volatile compounds

“…Among the chemical senses, the olfactory system detects volatile compounds, such as food odors and pheromones that can play a role as repellents or attractants, by means of olfactory sensilla mainly located in the antennae, but also in the maxillary palps and the ovipositor (Anton et al, 2003; Galizia & Roessler, 2010; Martin, Boto, Gomez‐Diaz, & Alcorta, 2013; Sollai et al, 2010). The olfactory sensory neurons (OSNs) housed in the olfactory sensilla transduce the information contained in odor stimuli into action potentials and project their axons to the brain, where they synapse with the local interneurons and the projection neurons in the glomeruli of the antennal lobes (Solari et al, 2016; Strausfeld & Hildebrand, 1999). Within the antennal lobes, the olfactory information is processed by local interneurons and then transmitted by the projection neurons to higher brain areas, including the main output areas like the mushroom body calyces and lateral horn (Galizia & Rössler, 2010; Galizia, 2014; Homberg, Christensen, & Hildebrand, 1989; Homberg, Montague, & Hildebrand, 1988; Ito et al, 1998; Stocker, 1994).…”