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Weaving H, Terblanche JS, English S. Heatwaves are detrimental to fertility in the viviparous tsetse fly. Proc Biol Sci 2024; 291:20232710. [PMID: 38471560 DOI: 10.1098/rspb.2023.2710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/01/2024] [Indexed: 03/14/2024] Open
Abstract
Heatwaves are increasing in frequency and intensity due to climate change, pushing animals beyond physiological limits. While most studies focus on survival limits, sublethal effects on fertility tend to occur below lethal thresholds, and consequently can be as important for population viability. Typically, male fertility is more heat-sensitive than female fertility, yet direct comparisons are limited. Here, we measured the effect of experimental heatwaves on tsetse flies, Glossina pallidipes, disease vectors and unusual live-bearing insects of sub-Saharan Africa. We exposed males or females to a 3-day heatwave peaking at 36, 38 or 40°C for 2 h, and a 25°C control, monitoring mortality and reproduction over six weeks. For a heatwave peaking at 40°C, mortality was 100%, while a 38°C peak resulted in only 8% acute mortality. Females exposed to the 38°C heatwave experienced a one-week delay in producing offspring, whereas no such delay occurred in males. Over six weeks, heatwaves resulted in equivalent fertility loss in both sexes. Combined with mortality, this lead to a 10% population decline over six weeks compared to the control. Furthermore, parental heatwave exposure gave rise to a female-biased offspring sex ratio. Ultimately, thermal limits of both survival and fertility should be considered when assessing climate change vulnerability.
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Affiliation(s)
- Hester Weaving
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - John S Terblanche
- Department of Conservation Ecology & Entomology, Stellenbosch University, Stellenbosch, South Africa
| | - Sinead English
- School of Biological Sciences, University of Bristol, Bristol, UK
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Moyano A, Croce AC, Scolari F. Pathogen-Mediated Alterations of Insect Chemical Communication: From Pheromones to Behavior. Pathogens 2023; 12:1350. [PMID: 38003813 PMCID: PMC10675518 DOI: 10.3390/pathogens12111350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/26/2023] Open
Abstract
Pathogens can influence the physiology and behavior of both animal and plant hosts in a manner that promotes their own transmission and dispersal. Recent research focusing on insects has revealed that these manipulations can extend to the production of pheromones, which are pivotal in chemical communication. This review provides an overview of the current state of research and available data concerning the impacts of bacterial, viral, fungal, and eukaryotic pathogens on chemical communication across different insect orders. While our understanding of the influence of pathogenic bacteria on host chemical profiles is still limited, viral infections have been shown to induce behavioral changes in the host, such as altered pheromone production, olfaction, and locomotion. Entomopathogenic fungi affect host chemical communication by manipulating cuticular hydrocarbons and pheromone production, while various eukaryotic parasites have been observed to influence insect behavior by affecting the production of pheromones and other chemical cues. The effects induced by these infections are explored in the context of the evolutionary advantages they confer to the pathogen. The molecular mechanisms governing the observed pathogen-mediated behavioral changes, as well as the dynamic and mutually influential relationships between the pathogen and its host, are still poorly understood. A deeper comprehension of these mechanisms will prove invaluable in identifying novel targets in the perspective of practical applications aimed at controlling detrimental insect species.
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Affiliation(s)
- Andrea Moyano
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, I-27100 Pavia, Italy; (A.M.); (A.C.C.)
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
| | - Anna Cleta Croce
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, I-27100 Pavia, Italy; (A.M.); (A.C.C.)
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
| | - Francesca Scolari
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, I-27100 Pavia, Italy; (A.M.); (A.C.C.)
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
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3
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Weaving H, Lord JS, Haines L, English S. No evidence for direct thermal carryover effects on starvation tolerance in the obligate blood-feeder, Glossina morsitans morsitans. Ecol Evol 2023; 13:e10652. [PMID: 37869424 PMCID: PMC10585125 DOI: 10.1002/ece3.10652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/10/2023] [Accepted: 09/28/2023] [Indexed: 10/24/2023] Open
Abstract
Thermal stress during development can prime animals to cope better with similar conditions in later life. Alternatively, negative effects of thermal stress can persist across life stages and result in poorer quality adults (negative carryover effects). As mean temperatures increase due to climate change, evidence for such effects across diverse taxa is required. Using Glossina morsitans morsitans, a species of tsetse fly and vector of trypanosomiasis, we asked whether (i) adaptive developmental plasticity allows flies to survive for longer under food deprivation when pupal and adult temperatures are matched; or (ii) temperature stress during development persists into adulthood, resulting in a greater risk of death. We did not find any advantage of matched pupal and adult temperature in terms of improved starvation tolerance, and no direct negative carryover effects were observed. There was some evidence for indirect carryover effects-high pupal temperature produced flies of lower body mass, which, in turn, resulted in greater starvation risk. However, adult temperature had the largest impact on starvation tolerance by far: flies died 60% faster at 31°C than those experiencing 25°C, consequently reducing survival time from a median of 8 (interquartile range (IQR) 7-9) to 5 (IQR 5-5.25) days. This highlights differences in temperature sensitivity between life stages, as there was no direct effect of pupal temperature on starvation tolerance. Therefore, for some regions of sub-Saharan Africa, climate change may result in a higher mortality rate in emerging tsetse while they search for their first blood meal. This study reinforces existing evidence that responses to temperature are life stage specific and that plasticity may have limited capacity to buffer the effects of climate change.
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Affiliation(s)
- Hester Weaving
- School of Biological SciencesUniversity of BristolBristolUK
| | - Jennifer S. Lord
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Lee Haines
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
- Department of Biological SciencesUniversity of Notre DameNotre DameIndianaUSA
| | - Sinead English
- School of Biological SciencesUniversity of BristolBristolUK
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Hargrove JW. Improved estimates of abortion rates in tsetse (Glossina spp.). MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:600-615. [PMID: 37144648 DOI: 10.1111/mve.12659] [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: 07/19/2022] [Accepted: 04/06/2023] [Indexed: 05/06/2023]
Abstract
Abortion rates were assessed among 170, 846 tsetse (154,228 Glossina pallidipes and 19,618 Glossina morsitans morsitans) sampled in Zimbabwe in 1988-1999. The study produced improved estimates of abortion rates and how these varied with fly age and size and temperatures experienced during pregnancy. An abortion was diagnosed if the uterus was empty and the largest oocyte <0.82 of the expected mature length. Abortion rates for G. pallidipes and G. m. morsitans were 0.64% (95% ci: 0.59-0.69) and 0.83% (0.62-1.10) for trapped flies and 2.03% (1.77-2.31) and 1.55% (1.20-1.98) for flies from artificial refuges. Abortion rates increased with increasing temperature and decreased with increasing wing length and wing fray. Contrary to laboratory findings, abortion rates did not increase in the oldest flies. Percentages of tsetse with empty uteri, regardless of abortion status, were significantly higher than estimated abortion percentages. For tsetse from traps, 4.01% (95% ci: 3.90-4.13) of G. pallidipes and 2.52% (2.14-2.95) of G. m. morsitans had empty uteri; for flies from artificial refuges, the percentages were 12.69% (12.07-13.34) and 14.90% (13.82-16.02), respectively. Abortion losses are small relative to losses at all other stages of life.
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Affiliation(s)
- J W Hargrove
- SACEMA, University of Stellenbosch, Stellenbosch, South Africa
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Adden AK, Haines LR, Acosta-Serrano Á, Prieto-Godino LL. Tsetse flies ( Glossina morsitans morsitans) choose birthing sites guided by substrate cues with no evidence for a role of pheromones. Proc Biol Sci 2023; 290:20230030. [PMID: 37122250 PMCID: PMC10130706 DOI: 10.1098/rspb.2023.0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Tsetse flies significantly impact public health and economic development in sub-Saharan African countries by transmitting the fatal disease African trypanosomiasis. Unusually, instead of laying eggs, tsetse birth a single larva that immediately burrows into the soil to pupate. Where the female chooses to larviposit is, therefore, crucial for offspring survival. Previous laboratory studies suggested that a putative larval pheromone, n-pentadecane, attracts gravid female Glossina morsitans morsitans to appropriate larviposition sites. However, this attraction could not be reproduced in field experiments. Here, we resolve this disparity by designing naturalistic laboratory experiments that closely mimic the physical characteristics found in the wild. We show that gravid G. m. morsitans were neither attracted to the putative pheromone nor, interestingly, to pupae placed in the soil. By contrast, females appear to choose larviposition sites based on environmental substrate cues. We conclude that, among the many cues that likely contribute to larviposition choice in nature, substrate features are a main determinant, while we failed to find evidence for a role of pheromones.
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Affiliation(s)
- Andrea K Adden
- Neural Circuits and Evolution Laboratory, Francis Crick Institute, London NW1 1AT, UK
| | - Lee R Haines
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Álvaro Acosta-Serrano
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Lucia L Prieto-Godino
- Neural Circuits and Evolution Laboratory, Francis Crick Institute, London NW1 1AT, UK
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Benoit JB, Lahondère C, Attardo GM, Michalkova V, Oyen K, Xiao Y, Aksoy S. Warm Blood Meal Increases Digestion Rate and Milk Protein Production to Maximize Reproductive Output for the Tsetse Fly, Glossina morsitans. INSECTS 2022; 13:997. [PMID: 36354821 PMCID: PMC9695897 DOI: 10.3390/insects13110997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/21/2022] [Accepted: 10/23/2022] [Indexed: 06/16/2023]
Abstract
The ingestion of blood represents a significant burden that immediately increases water, oxidative, and thermal stress, but provides a significant nutrient source to generate resources necessary for the development of progeny. Thermal stress has been assumed to solely be a negative byproduct that has to be alleviated to prevent stress. Here, we examined if the short thermal bouts incurred during a warm blood meal are beneficial to reproduction. To do so, we examined the duration of pregnancy and milk gland protein expression in the tsetse fly, Glossina morsitans, that consumed a warm or cool blood meal. We noted that an optimal temperature for blood ingestion yielded a reduction in the duration of pregnancy. This decline in the duration of pregnancy is due to increased rate of blood digestion when consuming warm blood. This increased digestion likely provided more energy that leads to increased expression of transcript for milk-associated proteins. The shorter duration of pregnancy is predicted to yield an increase in population growth compared to those that consume cool or above host temperatures. These studies provide evidence that consumption of a warm blood meal is likely beneficial for specific aspects of vector biology.
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Affiliation(s)
- Joshua B. Benoit
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., New Haven, CT 06510, USA
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Chloé Lahondère
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- The Fralin Life Science Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Center of Emerging, Zoonotic and Arthropod-Borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- The Global Change Center, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
- Department of Entomology at Virginia Polytechnic Institute and State Univerity, Blacksburg, VA 24061, USA
| | - Geoffrey M. Attardo
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., New Haven, CT 06510, USA
- Department of Entomology and Nematology, Division of Agriculture and Natural Resources, University of California Davis, Davis, CA 95616, USA
| | - Veronika Michalkova
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., New Haven, CT 06510, USA
- Section of Molecular and Applied Zoology, Institute of Zoology, Slovak Academy of Sciences, 814 38 Bratislava, Slovakia
| | - Kennan Oyen
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Yanyu Xiao
- Department of Mathematical Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Serap Aksoy
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St., New Haven, CT 06510, USA
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Horn T, Narov KD, Panfilio KA. Persistent Parental RNAi in the Beetle Tribolium castaneum Involves Maternal Transmission of Long Double-Stranded RNA. ADVANCED GENETICS (HOBOKEN, N.J.) 2022; 3:2100064. [PMID: 36620196 PMCID: PMC9744488 DOI: 10.1002/ggn2.202100064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Indexed: 01/11/2023]
Abstract
Parental RNA interference (pRNAi) is a powerful and widely used method for gene-specific knockdown. Yet in insects its efficacy varies between species, and how the systemic response is transmitted from mother to offspring remains elusive. Using the beetle Tribolium castaneum, an RT-qPCR strategy to distinguish the presence of double-stranded RNA (dsRNA) from endogenous mRNA is reported. It is found that injected dsRNA is directly transmitted into the egg and persists throughout embryogenesis. Despite this depletion of dsRNA from the mother, it is shown that strong pRNAi can persist for months before waning at strain-specific rates. In seeking the receptor proteins for cellular uptake of long dsRNA into the egg, a phylogenomics profiling approach of candidate proteins is also presented. A visualization strategy based on taxonomically hierarchical assessment of orthology clustering data to rapidly assess gene age and copy number changes, refined by sequence-based evidence, is demonstrated. Repeated losses of SID-1-like channel proteins in the arthropods, including wholesale loss in the Heteroptera (true bugs), which are nonetheless highly sensitive to pRNAi, are thereby documented. Overall, practical considerations for insect pRNAi against a backdrop of outstanding questions on the molecular mechanism of dsRNA transmission for long-term, systemic knockdown are elucidated.
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Affiliation(s)
- Thorsten Horn
- Institute for Zoology: Developmental BiologyUniversity of CologneZülpicher Straße 47b50674CologneGermany
| | - Kalin D. Narov
- School of Life SciencesUniversity of WarwickGibbet Hill CampusCoventryCV4 7ALUK
| | - Kristen A. Panfilio
- Institute for Zoology: Developmental BiologyUniversity of CologneZülpicher Straße 47b50674CologneGermany,School of Life SciencesUniversity of WarwickGibbet Hill CampusCoventryCV4 7ALUK
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Barreaux AMG, Higginson AD, Bonsall MB, English S. Incorporating effects of age on energy dynamics predicts nonlinear maternal allocation patterns in iteroparous animals. Proc Biol Sci 2022; 289:20211884. [PMID: 35168397 PMCID: PMC8848239 DOI: 10.1098/rspb.2021.1884] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Iteroparous parents face a trade-off between allocating current resources to reproduction versus maximizing survival to produce further offspring. Parental allocation varies across age and follows a hump-shaped pattern across diverse taxa, including mammals, birds and invertebrates. This nonlinear allocation pattern lacks a general theoretical explanation, potentially because most studies focus on offspring number rather than quality and do not incorporate uncertainty or age-dependence in energy intake or costs. Here, we develop a life-history model of maternal allocation in iteroparous animals. We identify the optimal allocation strategy in response to stochasticity when energetic costs, feeding success, energy intake and environmentally driven mortality risk are age-dependent. As a case study, we use tsetse, a viviparous insect that produces one offspring per reproductive attempt and relies on an uncertain food supply of vertebrate blood. Diverse scenarios generate a hump-shaped allocation when energetic costs and energy intake increase with age and also when energy intake decreases and energetic costs increase or decrease. Feeding success and environmentally driven mortality risk have little influence on age-dependence in allocation. We conclude that ubiquitous evidence for age-dependence in these influential traits can explain the prevalence of nonlinear maternal allocation across diverse taxonomic groups.
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Affiliation(s)
- Antoine M G Barreaux
- School of Biological sciences, University of Bristol, Bristol BS8 1TQ, UK.,CIRAD, UMR INTERTRYP, F-34398 Montpellier, France.,INTERTRYP, Univ Montpellier, CIRAD, IRD, 34000 Montpellier, France
| | - Andrew D Higginson
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK
| | - Michael B Bonsall
- Department of Zoology, Mathematical Ecology Research Group, University of Oxford, Oxford OX1 3PS, UK.,St Peters College, Oxford OX1 2DL, UK
| | - Sinead English
- School of Biological sciences, University of Bristol, Bristol BS8 1TQ, UK
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