A large diversity of odorant molecules reaches the antennae of insects at any given time. The key role of odorant receptors (ORs) is to translate the chemical complexity of the environment into interpretable neuronal signals. To this goal, ORs exhibit a wide range of ligand specificities: many ORs are promiscuous, responding to dozens of chemically diverse odorants, and some ORs are...
Understanding how odors are represented in the locust antennal lobe, which comprises over 2,000 glomeruli, has been a longstanding challenge. To investigate this phenomenon, we used the CRISPR-Cas9 system to generate transgenic migratory locusts (Locusta migratoria) that expressed the genetically encoded calcium indicator, GCaMP6f, in their olfactory sensory neurons. Using two-photon...
The red palm weevil (Rhynchophorus ferrugineus – RPW) and the American palm weevil (Rhynchophorus palmarum – APW) are major pests that cause significant economic losses to palm crops. These two species use aggregation pheromones to gather for feeding and mating on their host plants, specifically palm trees. Despite their close phylogenetic relationship, RPW and APW are allopatric species...
Using protein structure modeling-based methods, we recently identified very distant insect Or/Gr homologs, to define a protein superfamily we named 7-Transmembrane domain Ion Channels (7TMICs). 7TMICs are present across the tree of life and likely originated in the Last Universal Common Ancestor (~4 billion years ago). 7TMICs can be classified into two families: Class-A, which includes the...
A striking dichotomy in olfactory systems exists between mammals, which use G-protein coupled receptors (GPCRs) for odour detection, and insects, which rely on odour-gated ion channels, including the Ionotropic receptor (Ir) repertoire, which is distantly related to synaptic ionotropic glutamate receptor (iGluR) family. Here we report the first evidence for a GPCR signaling pathway in shaping...
Living beings are not isolated and interact with each other. These interactions are often mediated by chemical odorants but how the evolution of the olfactory system can determine intra- and inter-specific interactions remains unclear. A peculiar example is the queen mandibular pheromone (QMP) in Apis mellifera, which inhibits the development of the ovaries in the conspecific workers (hence...
Background Insect Ionotropic Receptors (IRs) are a relatively uncharted territory. Some studies have documented IR activation by recording neuronal activity in situ, others by their heterologous expression in Xenopus oocytes or misexpressing IRs from Drosophila melanogaster or from the related D. sechellia into the D. melanogaster “ionotropic receptor decoder” neuron, which lacks...
