Anatomical organization of the cerebrum of the desert locust Schistocerca gregaria

Abstract

The desert locust Schistocerca gregaria is a major agricultural pest in North Africa and the Middle East. As such, it has been intensely studied, in particular with respect to population dynamics, sensory processing, feeding behavior flight and locomotor control, migratory behavior, and its neuroendocrine system. Being a long-range migratory species, neural mechanisms underlying sky compass orientation have been studied in detail. To further understand neuronal interactions in the brain of the locust, a deeper understanding of brain organization in this insect has become essential. As a follow-up of a previous study illustrating the layout of the locust brain (Kurylas et al. in J Comp Neurol 484:206-223, 2008), we analyze the cerebrum, the central brain minus gnathal ganglia, of the desert locust in more detail and provide a digital three-dimensional atlas of 48 distinguishable brain compartments and 7 major fiber tracts and commissures as a basis for future functional studies. Neuropils were three-dimensionally reconstructed from synapsin-immunostained whole mount brains. Neuropil composition and their internal organization were analyzed and compared to the neuropils of the fruit fly Drosophila melanogaster. Most brain areas have counterparts in Drosophila. Some neuropils recognized in the locust, however, have not been identified in the fly while certain areas in the fly could not be distinguished in the locust. This study paves the way for more detailed anatomical descriptions of neuronal connections and neuronal cell types in the locust brain, facilitates interspecies comparisons among insect brains and points out possible evolutionary differences in brain organization between hemi- and holometabolous insects.

Encoding of wind direction by central neurons inDrosophila

“…Although morphologically similar regions of the brain have been described in other insects (Immonen, Dacke, Heinze, & el Jundi, 2017;von Hadeln, Althaus, Häger, & Homberg, 2018), to our knowledge, little is known about the function of these regions of the brain. Neurons in the central complex of other insects have been shown to respond to mechanosensory stimuli (U.…”

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

“…To provide the anatomical basis for those future studies, we have carried out a combination of immunohistochemical stainings and 3D reconstructions of Bogong moth brains and produced a comprehensive description of all major regions in the brain of this species, similar to those published for the Monarch butterfly (Heinze & Reppert, ), the dung beetle (Immonen, Dacke, Heinze, & el Jundi, ), the fruit fly (Ito et al, ; Jenett et al, ), and the locust (von Hadeln, Althaus, Häger, & Homberg, ). To account for inter‐individual variation, we additionally generated a standardized brain atlas, which robustly describes the average shape of the male Bogong moth brain.…”

Neuronal constituents and putative interactions within the Drosophila ellipsoid body neuropil

“…shaped body, respectively) are arranged in an antero-posterior fashion. This difference is reflective 830 of a 60° anterior tilt of the locust neuraxis, as evidenced by the peduncle, which extends 831 horizontally in flies but is oriented almost vertically in the locust (Hadeln et al, 2018 (EBa/ic/oc/ip/op; Fig.1). Considering the tilt in neuraxis, we posit that dorsal strata (layers 1-2) of 839 the locust CBL roughly correspond to more posterior domains (EBip/op) of the fly EB, whereas 840 ventral strata (layers 3-6) correspond to more anterior EB domains (EBa/ic/oc).…”