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Petelski I, Günzel Y, Sayin S, Kraus S, Couzin-Fuchs E. Synergistic olfactory processing for social plasticity in desert locusts. Nat Commun 2024; 15:5476. [PMID: 38942759 PMCID: PMC11213921 DOI: 10.1038/s41467-024-49719-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 06/11/2024] [Indexed: 06/30/2024] Open
Abstract
Desert locust plagues threaten the food security of millions. Central to their formation is crowding-induced plasticity, with social phenotypes changing from cryptic (solitarious) to swarming (gregarious). Here, we elucidate the implications of this transition on foraging decisions and corresponding neural circuits. We use behavioral experiments and Bayesian modeling to decompose the multi-modal facets of foraging, revealing olfactory social cues as critical. To this end, we investigate how corresponding odors are encoded in the locust olfactory system using in-vivo calcium imaging. We discover crowding-dependent synergistic interactions between food-related and social odors distributed across stable combinatorial response maps. The observed synergy was specific to the gregarious phase and manifested in distinct odor response motifs. Our results suggest a crowding-induced modulation of the locust olfactory system that enhances food detection in swarms. Overall, we demonstrate how linking sensory adaptations to behaviorally relevant tasks can improve our understanding of social modulation in non-model organisms.
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Affiliation(s)
- Inga Petelski
- International Max Planck Research School for Quantitative Behavior, Ecology and Evolution from lab to field, 78464, Konstanz, Germany
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78464, Konstanz, Germany
| | - Yannick Günzel
- International Max Planck Research School for Quantitative Behavior, Ecology and Evolution from lab to field, 78464, Konstanz, Germany.
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany.
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78464, Konstanz, Germany.
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464, Konstanz, Germany.
| | - Sercan Sayin
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464, Konstanz, Germany
| | - Susanne Kraus
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany
| | - Einat Couzin-Fuchs
- Department of Biology, University of Konstanz, 78464, Konstanz, Germany.
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78464, Konstanz, Germany.
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464, Konstanz, Germany.
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Cullen DA, Rogers SM. Editorial for Journal of Insect Physiology Special Issue: A century of research into locust phase polyphenism. JOURNAL OF INSECT PHYSIOLOGY 2023; 144:104473. [PMID: 36572335 DOI: 10.1016/j.jinsphys.2022.104473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
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Vernier C, Barthes N, Chapuis MP, Foucaud J, Huguenin J, Leménager N, Piou C. Faeces' odours attract gregarious locust hoppers. JOURNAL OF INSECT PHYSIOLOGY 2022; 143:104454. [PMID: 36343666 DOI: 10.1016/j.jinsphys.2022.104454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 10/14/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Collective motion is one of the most impressive common features of gregarious locusts: once formed, bands and swarms get moving for long distances. It was shown that visual perception of neighbours plays a key role in maintaining marching behaviour at a local scale. But at a larger scale, mechanisms underlying band cohesion are less understood. It was shown in several field studies that individuals separated from the band were able to get back to the group, even after being separated since a night. In this context, faeces' odours could be a possible indicator of the recent passage of a group. In this study, we tested if nymphs are attracted by faeces' odours and if this effect is modulated by the age of the faeces. To this end, we conducted individual olfactometric behavioural assays of 3rd instar hoppers of desert locust, Schistocerca gregaria, exposed to odours of 1 h-old and 24 h-old faeces. We also used Gas Chromatography-Mass Spectrometry (GC-MS) to identify odours' volatile organic compounds from faeces. The results of behavioural assays indicated a strong attractive effect of faeces, with no preference for one of the two faecal age classes. Nymphs spent significantly more time in the side of the olfactometer where the faeces' odours came from, and 72.7% of tested individuals chose this side first. We filtered and annotated 11 volatile organic compounds present in both fresh and old faeces in GC-MS analyses, including guaiacol and phenol, which are known to cause an aggregative effect on desert locusts. As the attractive effect lasted over 24 h, band's faeces could still have an attractive effect when individuals are separated from the band since one day. In this situation, latecomers individuals would be able to get back to the group by following the traces of their predecessors.
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Affiliation(s)
- Camille Vernier
- CIRAD, UMR CBGP, F-34398 Montpellier, France; CBGP, Université de Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France.
| | - Nicolas Barthes
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul Valéry Montpellier, EPHE, IRD, F-34293 Montpellier, France
| | - Marie-Pierre Chapuis
- CIRAD, UMR CBGP, F-34398 Montpellier, France; CBGP, Université de Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Julien Foucaud
- CBGP, Université de Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France; INRAE, UMR CBGP, F-34398 Montpellier, France
| | - Joris Huguenin
- Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Université de Montpellier, Université Paul Valéry Montpellier, EPHE, IRD, F-34293 Montpellier, France
| | - Nicolas Leménager
- CIRAD, UMR CBGP, F-34398 Montpellier, France; CBGP, Université de Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
| | - Cyril Piou
- CIRAD, UMR CBGP, F-34398 Montpellier, France; CBGP, Université de Montpellier, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
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Chen D, Hou L, Wei J, Guo S, Cui W, Yang P, Kang L, Wang X. Aggregation pheromone 4-vinylanisole promotes the synchrony of sexual maturation in female locusts. eLife 2022; 11:74581. [PMID: 35258453 PMCID: PMC8903828 DOI: 10.7554/elife.74581] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Reproductive synchrony generally occurs in various group-living animals. However, the underlying mechanisms remain largely unexplored. The migratory locust, Locusta migratoria, a worldwide agricultural pest species, displays synchronous maturation and oviposition when forms huge swarm. The reproductive synchrony among group members is critical for the maintenance of locust swarms and population density of next generation. Here, we showed that gregarious female locusts displayed more synchronous sexual maturation and oviposition than solitarious females and olfactory deficiency mutants. Only the presence of gregarious male adults can stimulate sexual maturation synchrony of female adults. Of the volatiles emitted abundantly by gregarious male adults, the aggregation pheromone, 4-vinylanisole, was identified to play key role in inducing female sexual maturation synchrony. This maturation-accelerating effect of 4-vinylanisole disappeared in the females of Or35-/- lines, the mutants of 4-vinylanisole receptor. Interestingly, 4-vinylanisole displayed a time window action by which mainly accelerates oocyte maturation of young females aged at middle developmental stages (3–4 days post adult eclosion). We further revealed that juvenile hormone/vitellogenin pathway mediated female sexual maturation triggered by 4-vinylanisole. Our results highlight a ‘catch-up’ strategy by which gregarious females synchronize their oocyte maturation and oviposition by time-dependent endocrinal response to 4-vinylanisole, and provide insight into reproductive synchrony induced by olfactory signal released by heterosexual conspecifics in a given group. Since 2019, a plague of flying insects known as migratory locusts has been causing extensive damage to crops in East Africa. Migratory locusts sometimes live a solitary lifestyle but, if environmental conditions allow, they form large groups containing millions of individuals known as swarms that are responsible for causing locust plagues.Locusts are able to maintain such large swarms because they can aggregate and synchronize. When they live in swarms, individual locusts produce odors that are sensed by other individuals in the group. For example, an aggregation pheromone, called 4-vinylanisole, is known to help keep large groups of locusts together. However, it is less clear how odors synchronize the reproductive cycles of the females in a swarm so that they are ready to mate with males and lay their eggs at the same time. To address this question, Chen et al. examined when female locusts reached sexual maturity after they were exposed to odors produced by other locusts living alone or in groups. The experiments found that only 4-vinylanisole, which was abundantly released by adult male locusts living in groups, stimulated female locusts to reach sexual maturity at the same time. This odor increased the levels of a hormone known as juvenile hormone in less-developed females to help them reach sexual maturity sooner. These findings demonstrate that when migratory locusts are living in swarms, male locusts promote the female locusts to reach sexual maturity at the same time by promoting less-developed females to ‘catch up’ with other females in the group. A next step will be to investigate the neural and molecular mechanisms underlying the ‘catch up’ effect induced by 4-vinylanisole.
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Affiliation(s)
- Dafeng Chen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Li Hou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jianing Wei
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Siyuan Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Weichan Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Pengcheng Yang
- Beijing Institutes of Life Sciences, Chinese Academy of Sciences, Beijing, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.,Beijing Institutes of Life Sciences, Chinese Academy of Sciences, Beijing, China
| | - Xianhui Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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