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Early detection of cancer is critical in medical sciences, as the sooner a cancer is diagnosed, the higher are the chances of recovery. Tumour cells are characterized by specific volatile organic compounds (VOCs) that can be used as cancer biomarkers. Through olfactory associative learning, animals can be trained to detect these VOCs. Insects such as ants have a refined sense of smell, and can be easily and rapidly trained with olfactory conditioning. Using urine from patient-derived xenograft mice as stimulus, we demonstrate that individual ants can learn to discriminate the odour of healthy mice from that of tumour-bearing mice and do so after only three conditioning trials. After training, they spend approximately 20% more time in the vicinity of the learned odour than beside the other stimulus. Chemical analyses confirmed that the presence of the tumour changed the urine odour, supporting the behavioural results. Our study demonstrates that ants reliably detect tumour cues in mice urine and have the potential to act as efficient and inexpensive cancer bio-detectors.

Additional file 3. Supplementary Data 2. Comparison of olfactory receptor gene repertoires from the present and previous studies. (A) Summary of the number of TAAR genes retrieved in our study and previous studies of four teleost species. (B) Summary of the number of OlfC genes retrieved in our study and previous studies of four teleost species. (C) Summary of the number of ORA genes retrieved in our study and previous studies of four teleost species. (D) Phylogenetic tree of Danio rerio TAAR genes retrieved in Hashiguchi and Nishida 2007 and our study. (E) Phylogenetic tree of Gasterosteus aculeatus TAAR genes retrieved in Azzouzi et al. 2015 and our study. (F) Phylogenetic tree of Oryzias latipes TAAR genes retrieved in Azzouzi et al. 2015 and our study. (G) Phylogenetic tree of Takifugu rubripes TAAR genes retrieved in Hashiguchi and Nishida 2007 and our study. (H) Phylogenetic tree of Danio rerio OlfC genes retrieved in Yang et al. 2019 and our study. (I) Phylogenetic tree of Gasterosteus aculeatus OlfC genes retrieved in Yang et al. 2019 and our study. (J) Phylogenetic tree of Oryzias latipes OlfC genes retrieved in Yang et al. 2019 and our study. (K) Phylogenetic tree of Takifugu rubripes OlfC genes retrieved in Yang et al. 2019 and our study. (L) Phylogenetic tree of Danio rerio ORA genes retrieved in Zapilko and Korsching 2016 and our study. (M) Phylogenetic tree of Gasterosteus aculeatus ORA genes retrieved in Zapilko and Korsching 2016 and our study. (N) Phylogenetic tree of Oryzias latipes ORA genes retrieved in Zapilko and Korsching 2016 and our study. (O) Phylogenetic tree of Takifugu rubripes ORA genes retrieved in Zapilko and Korsching 2016 and our study. (P) Phylogenetic tree of Polypterus senegalus OR genes retrieved in Bi X et al. 2021 and our study.

Les mortalités anormales d’abeilles domestiques identifiées par les apiculteurs dans leurs ruchers ont très tôt préfiguré le déclin généralisé des insectes, désormais scientifiquement avéré. Or ces derniers représentent l’un des tout premiers maillons de la chaîne trophique et jouent un rôle majeur dans des processus cruciaux comme la pollinisation, la dégradation de la matière organique et la structuration des sols. C’est pourquoi il est impératif de mieux les protéger.L’abeille domestique Apis mellifera est un insecte modèle des recherches en biologie. L’observation méticuleuse de ses comportements individuels et collectifs, décuplée par le décryptage de son génome, a donné lieu à la découverte et à la caractérisation de nouveaux modes de perception de l’environnement, de processus de communication interindividuelle, de mécanismes d’orientation dans l’espace ou de capacités cognitives. C’est donc sur cette espèce phare que de nombreuses équipes de recherche ont concentré leurs travaux étudiant les effets comportementaux et les modes d’action neurophysiologiques des insecticides.Comment fonctionne une colonie en bonne santé ? Quels effets les insecticides ont-ils sur les abeilles adultes, sur les larves, sur leurs capacités à s’orienter, à se déplacer ou à communiquer ? Quels mécanismes biologiques sont altérés ? Comment décrypter les symptômes qui nous alertent d’une intoxication ?C’est à toutes ces questions, essentielles pour notre avenir, que les auteurs de ce livre s’attachent à répondre.

Additional file 1: Figure S1. Diversity of the olfactory receptor gene repertoire in ray-finned fishes. Figure S2. Distribution of ORA7 and ORA8 subfamilies in ray-finned fishes. Figure S3. Distribution of birth and death rates of OR, TAAR, OlfC and ORA genes in ray-finned fishes. Figure S4. Correlation of the number of gene losses (or gene gains) between gene families, estimated using the 368 branches of the phylogenetic tree. Figure S5. Correlation between the number of OR, TAAR and OlfC pseudogenes in 185 ray-finned fishes. Figure S6. Narial tubes of four species of ray-finned fishes with complex olfactory organs and large gene repertoires. Figure S7. Takifugu rubripes, USNM 57620, 290 mm TL.

Additional file 4. Supplementary Data 3. (A) Phylogeny of OR genes from 44 species representing 44 orders of ray-finned fishes sampled in this study. Branches are colored according to the gene subfamily classification. (B) Phylogeny of all TAAR genes retrieved from 185 ray-finned fishes. Branches are colored according to gene family classification. Outgroup sequences (nonTAAR GPCRs) are colored in black. (C) Phylogeny of all OlfC genes retrieved from 185 ray-finned fish. Branches are colored according to the gene subfamily classification. Outgroup sequences (CasR and V2R2 genes) are colored in black. (D) Phylogeny of all ORA genes retrieved from 185 ray-finned fishes. Branches are colored according to the gene subfamily classification. Outgroup sequences (T2R genes) are colored in black.

Motivation can critically influence learning and memory. Multiple neural mechanisms regulate motivational states, among which signalling via specific neuropeptides, such as NPY in vertebrates and NPF and its short variant sNPF in invertebrates, plays an essential role. The honeybee (Apis mellifera) is a privileged model for the study of appetitive learning and memory. Bees learn and memorize sensory cues associated with nectar reward while foraging and their learning is affected by their feeding state. However, the neural underpinnings of their motivational states remain poorly known. Here we focused on the short neuropeptide F (sNPF) and studied if it modulates the acquisition and formation of colour memories. Artificially increasing sNPF levels in partially fed foragers with a reduced motivation to learn colours resulted in significant colour learning and memory above the levels exhibited by starved foragers. Our results thus identify sNPF as a critical component of motivational processes involved in foraging and in the cognitive processes associated with this activity in honeybees.