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Saadi S, Bakkali N, Martín-Blázquez R, Badih A, Bakkali M. The Multivariate Regression Models Suggested as Standardising Tools for Categorising Solitarious and Gregarious Groups of the Main Pest Locust, Schistocerca gregaria, Produce Reproducible Results. INSECTS 2024; 15:102. [PMID: 38392521 PMCID: PMC10889186 DOI: 10.3390/insects15020102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/15/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
Outbreaks of the desert locust Schistocerca gregaria affect some of the poorest parts of Africa, with devastating outcomes. The key to understanding and dealing with this problematic adaptation to environmental changes is comparing gregarious and solitarious locusts, either in nature or in laboratories. Categorising locusts and detecting changes in their phase status is key to such comparisons, which have been hitherto based on applying mathematical models that use behavioural parameters and that each laboratory has to build anew for each experiment. All the models used thus far are different from one another. This implies differences in the tools used for the different experiments and by the different laboratories and, thus, potential noise in the results and interpretations. Standardising the way locusts are categorised is necessary if we want to reduce noise and errors. It is crucial if we seek to make the results and interpretations transferable and comparable between experiments and laboratories for such an important research area. To tackle this problem, we suggested two models as possible standardising tools. However, the problem of a lack of standardised tools re-emerged due to the doubts cast on the validity of those models. Here, we use samples from independent S. gregaria populations in order to test and validate those models. We discuss how successful the two models were at categorising solitarious, intermediate (transient), and gregarious nymph and adult S. gregaria samples. We highlight shortcomings and make more specific recommendations on the use of those models based on the precision differences they show when categorising solitarious and gregarious S. gregaria nymph and adult samples. Overall, both models have proven to be valid since their results were largely replicated and seem reproducible.
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Affiliation(s)
- Somia Saadi
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Fuentenueva S/N, 18071 Granada, Spain
| | - Noureddine Bakkali
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Fuentenueva S/N, 18071 Granada, Spain
| | - Rubén Martín-Blázquez
- Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas (CSIC), Avenida Américo Vespucio 26, Isla de la Cartuja, 41092 Sevilla, Spain
| | - Abdelmounim Badih
- Departamento de Ciencias Naturales, Agora Granada College International School, Urbanización Llanos de Silva S/N, 18230 Atarfe, Spain
| | - Mohammed Bakkali
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Fuentenueva S/N, 18071 Granada, Spain
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Abstract
Ambient temperature (Ta) is a critical abiotic factor for insects that cannot maintain a constant body temperature (Tb). Interestingly, Ta varies during the day, between seasons and habitats; insects must constantly cope with these variations to avoid reaching the deleterious effects of thermal stress. To minimize these risks, insects have evolved a set of physiological and behavioral thermoregulatory processes as well as molecular responses that allow them to survive and perform under various thermal conditions. These strategies range from actively seeking an adequate environment, to cooling down through the evaporation of body fluids and synthesizing heat shock proteins to prevent damage at the cellular level after heat exposure. In contrast, endothermy may allow an insect to fight parasitic infections, fly within a large range of Ta and facilitate nest defense. Since May (1979), Casey (1988) and Heinrich (1993) reviewed the literature on insect thermoregulation, hundreds of scientific articles have been published on the subject and new insights in several insect groups have emerged. In particular, technical advancements have provided a better understanding of the mechanisms underlying thermoregulatory processes. This present Review aims to provide an overview of these findings with a focus on various insect groups, including blood-feeding arthropods, as well as to explore the impact of thermoregulation and heat exposure on insect immunity and pathogen development. Finally, it provides insights into current knowledge gaps in the field and discusses insect thermoregulation in the context of climate change.
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Affiliation(s)
- Chloé Lahondère
- Department of Biochemistry, The Fralin Life Science Institute, The Global Change Center, Department of Entomology, Center of Emerging, Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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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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Youngblood JP, Cease AJ, Talal S, Copa F, Medina HE, Rojas JE, Trumper EV, Angilletta MJ, Harrison JF. Climate change expected to improve digestive rate and trigger range expansion in outbreaking locusts. ECOL MONOGR 2022. [DOI: 10.1002/ecm.1550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Arianne J. Cease
- School of Life Sciences Arizona State University Tempe AZ USA
- School of Sustainability Arizona State University Tempe AZ USA
| | - Stav Talal
- School of Life Sciences Arizona State University Tempe AZ USA
| | - Fernando Copa
- Universidad Autónoma Gabriel René Moreno Santa Cruz Bolivia
| | | | - Julio E. Rojas
- Departamento de Campañas Fitosanitarios Dirección de Protección Vegetal, SENAVE Paraguay
| | | | | | - Jon F. Harrison
- School of Life Sciences Arizona State University Tempe AZ USA
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