Glomerular identification in the antennal lobe of the male moth Helicoverpa armigera

Abstract

This study investigates anatomical organization of the antennal lobe (AL) glomeruli of the male cotton bollworm Helicoverpa armigera by synaptic antibody staining combined with three-dimensional reconstruction. To identify all glomeruli, their boundaries were accurately determined by means of several additional staining techniques visualizing the neuron categories forming the characteristic spherical neuropils. In total, 78-80 glomeruli were identified in the male H. armigera. The number of glomeruli was considerably larger than that previously reported in this species. Thus, compared with previous studies, we identified 15 new glomeruli, G63-G77. Most of them are located in the posterior part of the AL, which was previously considered to be a part of the protocerebrum. From the general anatomical organization of the AL glomeruli of H. armigera, we classified these neuropil structures into four groups, the macroglomerular complex, posterior complex, labial-palp pit organ glomerulus, and ordinary glomeruli. The complete identification of glomeruli is important for future studies seeking to explore further the coding mechanisms residing within the primary olfactory center of the moth brain. J. Comp. Neurol. 524:2993-3013, 2016. © 2016 Wiley Periodicals, Inc.

The brain of a nocturnal migratory insect, the Australian Bogong moth

“…As both male and female moths are faced with this identical challenge, the MGC, as well as any female‐specific glomeruli, are not expected to play a role in this behavior. As the number of identified glomeruli corresponds well to other noctuid moths, for example, Helicoverpa armigera (Zhao et al, ), we suggest that a direct, quantitative comparison of glomerular maps might be possible across species. The presented antennal lobe map thus provides a baseline for a detailed comparison of glomeruli not only between migratory and non‐migratory life stages of Bogong moths, but also between this species and non‐migratory moths.…”

A novel major output target for pheromone-sensitive projection neurons in male moths

“…The species used in this study, Helicoverpa armigera , utilizes two pheromone components: cis- 11-hexadecenal (Z11-16:Al) as primary component and cis- 9-hexadecenal (Z9-16:Al) as secondary component (Kehat and Dunkelblum, 1990). The MGC of this species contains three glomeruli, named cumulus, dorsomedial anterior (dma), and dorsomedial posterior (dmp; Skiri et al, 2005, Zhao et al, 2016a). Originating from the sensory neurons in specific antennal sensillae, signals resulting from the two pheromone components as well as one behavioral antagonist, cis -9-tetradecenal (Z9-14:Al), are received by the cumulus, dmp, and dma, respectively (see Figure 7 in Wu et al, 2015).…”

Dedicated acetic acid preference coded by broad spectrum ionotropic receptors in a moth species

“…Result showed that the ROIs from all acids were highly overlapped, indicating 1 glomerulus was involved in each area (Figure 4B). We later established 3-D structures of M. separata female antennal lobes with a standard atlas protocol [41–43], and compared the morphology of glomeruli with imaging results. The glomeruli reflecting ROIs were identical in terms of positions among individuals and no significant difference was observed in volumes.…”

“…Brains of moths were dissected and processed according to published works [43] and SYNORF1 (Developmental Studies Hybridoma Bank, IA, USA) antibody was used to label glomeruli in antennal lobes. Labelled antennal lobes were visualized with Alexa Fluor 488 goat anti-mouse secondary antibody (Invitrogen) and photo stacks were obtained with a Zeiss LSM710 Meta laser scanning microscope (Zeiss, Oberkochen, Germany).…”