Fig 3 - uploaded by Kevin Hidalgo
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Variation in body water content (a) and dry mass (b) among females An. coluzzii from D?ou, Oursi, Soumousso and Bama reared under RS (solid blue lines and triangles) and ODS (dashed red lines and squares) experimental conditions at 0, 2 and 7 days post-emergence. Values are means ? standard errors (SE). Different letters denote significant differences between experimental modalities (P < 0.05)
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Background
In West Africa, populations of the malaria vector mosquito, Anopheles coluzzii, are seasonally exposed to strong desiccating conditions during the dry season. Their dynamics strictly follows the pace of the availability of suitable larval development sites (water collections). Accordingly, mosquitoes can reproduce all year long where per...
Citations
... Water can be lost in insects through excretion, respiration and cuticular transpiration (Benoit, 2010;Chown and Nicolson, 2004;Wharton, 1985), and how this occurs can vary significantly among different species. Interestingly, most mosquito species have general mechanisms, as other insects have, to respond to dehydration along with more unique mechanisms for specific species, which are related to differences in their evolutionary and ecological backgrounds Gray and Bradley, 2005;Hidalgo et al., 2016;Holmes and Benoit, 2019). ...
... Ten replicates were performed per plant species. Proteins, sugars, glycogen, and triglycerides were quantified in each individual using the following protocol adapted from Foray et al. (2012) and Hidalgo et al. (2016). ...
Introduction
Animal nutritional strategies have been extensively studied in vertebrates, where generalism at the individual scale is the rule. In insect herbivores, the determinants of the nutritional strategy of individual-scale generalists remain poorly studied, and the focus has been placed mainly on the influence of plant defense. Moreover, the integration of a physiological dimension in such studies remains rare. Here, we investigated the determinants of the nutritional strategy of pre-diapausing pollen beetles, Brassicogethes aeneus, with a focus on the influence of macronutrients. Before their diapause, pollen beetles are known to feed from plants belonging to many different families. This raises three questions: (i) Is the generalism of pollen beetles a populational consequence of individuals specialized on different plant families? (ii) Do individuals feed at random on flowers available or do they have a particular nutritional strategy? and (iii) In case of non-random feeding choices, do pollen macronutrients explain this nutritional strategy?
Methods
To answer these questions, we used a series of laboratory experiments including feeding choice tests on flowers and artificial substrates, quantification of pollen nutrient content, quantification of the insect energetic budget, and performance experiments.
Results
We show that pollen beetles are generalist at the individual scale, and that clear and stable food preferences are established over a few hours in a multi-choice context. Pollen beetles prefer to feed on flowers with a carbohydrate-rich pollen, and this preference is adaptive since performance correlates positively with the plant carbohydrate content. This better performance may be explained by the fact that individuals feeding on carbohydrate-rich resources accumulate more glycogen and total energetic reserves.
Discussion
This study represents one of the few evidences of generalism at the individual scale in an herbivorous insect. It provides a better understanding of the nutritional strategy of a non-bee pollen feeder and shows the importance of carbohydrates in this strategy. It highlights the need to combine assessments of the plant macronutrient content and insect energetic budget in an adaptive framework to better understand the nutritional strategies of herbivores.
... Desiccation resistance or tolerance greatly contribute to shaping the geographic and habitat distribution of arthropod species (Dias et al., 2013;Ouisse et al., 2016). The different strategies that terrestrial arthropods have evolved for coping with desiccating conditions include increased body water amounts, reducing body water losses, or tolerating high levels of dehydration (Hadley, 1994;Hidalgo et al., 2014Hidalgo et al., , 2016. While improved desiccation resistance is helpful for insects that are frequently exposed to dehydrating environments, as is the case of most beetles thriving in arid regions (Zachariassen, 1991;Le Lagadec et al., 1998), some studies have also questioned the factors that can constrain the development of desiccation resistance and the ecological costs this could have for the individual (Chown et al., 2011). ...
In order to improve predictions of the impacts of climate change on insects, this study aimed to uncover how exposure to dry conditions can affect the biology of the invasive pest beetle Alphitobius diaperinus in terms of longevity, activity, water content, metabolic profiles, and fecundity. We measured desiccation resistance in adults of A. diaperinus by recording the time the beetles could survive desiccation stress. We found that the species was highly desiccation resistant, with about 50% of the insects exposed to desiccation being able to survive for 30 days, and some individuals even survived for up to 50 days at 10% ± 2 relative humidity. There was no evidence of active upregulation of sugars or other metabolites which the beetles could have used to better tolerate desiccation. Food deprivation affected both control (food deprivation, no desiccation) and treatment (food deprivation, desiccation) groups, as their metabolic phenotypes changed similarly after 1 week of treatment. Also, the activity of beetles from both control and desiccation treatments was similarly increased 2 weeks after the experiment had started. Even if there were no changes in the metabolic phenotypes of the insects experiencing desiccating conditions, beetles exposed to desiccation for 8 days had a significantly reduced reproductive output as compared with control insects. This result indicated a physiological cost of drought resistance or repair of stress-incurred damages. The exact nature of that effect (e.g., direct or indirect physiological costs) has not yet been described for tenebrionid beetles and should be investigated in future studies.
... Desiccation resistance or tolerance greatly contribute to shaping the geographic and habitat distribution of arthropod species (Dias et al., 2013;Ouisse et al., 2016). The different strategies that terrestrial arthropods have evolved for coping with desiccating conditions include increased body water amounts, reducing body water losses, or tolerating high levels of dehydration (Hadley, 1994;Hidalgo et al., 2014Hidalgo et al., , 2016. While improved desiccation resistance is helpful for insects that are frequently exposed to dehydrating environments, as is the case of most beetles thriving in arid regions (Zachariassen, 1991;Le Lagadec et al., 1998), some studies have also questioned the factors that can constrain the development of desiccation resistance and the ecological costs this could have for the individual (Chown et al., 2011). ...
Laboratory investigations on terrestrial model-species, typically of temperate origin, have demonstrated that terrestrial ectotherms can cope with daily temperature variations through rapid hardening responses. However, few studies have investigated this ability and its physiological basis in the field. Especially in polar regions, where the temporal and spatial temperature variations can be extreme, are hardening responses expected to be important. Here, we examined diurnal adjustments in heat and cold tolerance in the Greenlandic seed bug Nysius groenlandicus by collecting individuals for thermal assessment at different time points within and across days. We found a significant correlation between observed heat or cold tolerance and the ambient microhabitat temperatures at the time of capture, indicating that N. groenlandicus continuously and within short time-windows respond physiologically to thermal changes and/or other environmental variables in their microhabitats. Secondly, we assessed underlying metabolomic fingerprints using GC-MS metabolomics in a subset of individuals collected during days with either low or high temperature variation. Concentrations of metabolites, including sugars, polyols, and free amino acids varied significantly with time of collection. For instance, we detected elevated sugar levels in animals caught at the lowest daily field temperatures. Polyol concentrations were lower in individuals collected in the morning and evening and higher at midday and afternoon, possibly reflecting changes in temperature. Additionally, changes in concentrations of metabolites associated with energetic metabolism were observed across collection times. Our findings suggest that in these extreme polar environments hardening responses are marked and likely play a crucial role for coping with microhabitat temperature variation on a daily scale, and that metabolite levels are actively altered on a daily basis.
... Metabolic profiles of four An. coluzzii mosquito populationsoriginally from arid and humid regions of north and southwest of Burkina Faso (West Africa)were assessed using targeted GC/MS analysis to identify potential metabolite signatures in response to severe desiccating conditions during the dry season [47]. Wild-caught An. coluzzii from Oursi and Déou (permanent and temporary breeding habitats from north of Burkina Faso), and wild-caught An. coluzzii from Bama and Soumousso (permanent and temporary breeding habitats from southwest of Burkina Faso) were first used to establish colonies in the laboratory. ...
... Some differences in metabolite abundance among An. coluzzii populations, and under the two specific conditions studied, led authors to suggest that females from temporary northern Trends in Parasitology habitats could have a strong aestivation strategy to overcome desiccation [47]. The molecular mechanisms behind environmental adaptability in mosquitoes, and the impact on diseasetransmission, have yet to be further addressed. ...
... Both panels highlight an assortment of GC/MS and LC/MSbased instrumentation used in the listed references. Abbreviations: DI, direct infusion; FTICRMS, Fourier-transform ion cyclotron resonance mass spectrometer; IC, ion chromatography; OTMS, OrbiTrap mass spectrometer; QTOFMS, quadrupole time-of-flight mass spectrometer; SQMS, single-quadrupole mass spectrometer; TQMS, triple-quadrupole mass spectrometer.Figure 1cites[33][34][35][36][37][38]40,41,45,47,[50][51][52][53][54][55][56][58][59][60]. ...
Nearly half a million people die annually due to mosquito-borne diseases. Despite aggressive mosquito population-control efforts, current strategies are limited in their ability to control these vectors. A better understanding of mosquito metabolism through modern approaches can contribute to the discovery of novel metabolic targets and/or regulators and lead to the development of better mosquito-control strategies. Currently, cutting-edge technologies such as gas or liquid chromatography–mass spectrometry-based metabolomics are considered 'mature technologies' in many life-science disciplines but are still an emerging area of research in medical entomology. This review primarily discusses recent developments and progress in the application of mass spectrometry-based metabolomics to answer multiple biological questions related to mosquito metabolism.
... Depending on the species, eggs or larvae can survive over winter and do not continue development (Saari et al., 2019). For example, the populations of mosquito inhabiting contrasted ecological areas used different aestivation strategies (Hidalgo et al., 2016). ...
A survey of immature Culicidae was conducted in diverse habitats of Souk-Ahras province (Northeast Algeria) between December 2018 and November 2019. Altogether, 12,861 specimens were collected and identified. Nineteen species of mosquitoes, belonging to two main subfamilies viz. Culicinae (accounts for 84.21 %) and Anophelinae (as 15.79 %), under 5 genera (Culex, Culiseta, Anopheles, Aedes and Uranotaenia). Among identified species, six were mentioned for the first time in the province of Souk-Ahras. The predominant species of the total mosquito fauna was Cx. pipiens L. with an abundance rate of 69.63 %. Two habitats were characterized by the highest prevalence of 11 species, Taoura (with 1 spp. Anophelinae, 10 spp. Culicinae) and Sedrata (with 11 spp. of Culicinae). However, Souk-Ahras site contained the largest abundance (41.20 %) belonging to 6 species. In addition, the spatial distribution of mosquitoes according to climatic factors (temperature, rainfall, humidity) was discussed. Data supported by some ecological indices of composition and structure revealed that the diversity level in Souk-Ahras province was between medium and very low compared to a scale varied between 0 and 1 (global Simpson index 0.50). The most diversified site in species was Taoura with the highest Shannon index value (2.11). Since vectors occurrence is constantly changing, it will be suggested that mosquito control should be intensified within other potential breeding sites in northeastern Algeria.
... The prevalence of Ae. albopictus in the urban environment is due to their plasticity to environmental changes and capability to live under resource-constrained urban environments (Bonizzoni et al. 2013;Hidalgo et al. 2016;Thongsripong et al. 2013;Zahouli et al. 2017). Furthermore, Ae. albopictus is a container-breeding specialist, which enables it to proliferate under the constraint of breeding in small artificial larval habitats that are prone to desiccation and have limited nutrient resources (Bonizzoni et al. 2013;Li et al. 2014). ...
Knowledge of the interrelationship of mosquito communities and land use changes is of paramount importance to understand the potential risk of mosquito disease transmission. This study examined the effects of land use types in urban, peri-urban and natural landscapes on mosquito community structure to test whether the urban landscape is implicated in increased prevalence of potentially harmful mosquitoes. Three land use types (park, farm, and forest nested in urban, peri-urban and natural landscapes, respectively) in Klang Valley, Malaysia, were surveyed for mosquito larval habitat, mosquito abundance and diversity. We found that the nature of human activities in land use types can increase artificial larval habitats, supporting container-breeding vector specialists such as Aedes albopictus, a dengue vector. In addition, we observed a pattern of lower mosquito richness but higher mosquito abundance, characterised by the high prevalence of Ae. albopictus in the urban landscape. This was also reflected in the mosquito community structure whereby urban and peri-urban landscapes were composed of mainly vector species compared to a more diverse mosquito composition in natural landscape. This study suggested that good environmental management practices in the tropical urban landscape are of key importance for effective mosquito-borne disease management.
... Ecological influences also contribute to the propensity of some species towards anthropophilia or endophilia, where limited distance between the mosquitoes and hosts is advantageous. Although no obvious trends in the physiological and molecular variations were observed in the highly anthropophilic species, An. coluzzii, of similar geographic origins, local adaptations persisted, and may have been influenced by specific microhabitats [107]. It is likely that the underlying adaptive mechanisms that are required to live in arid environments may have driven other highly anthropophilic species (e.g., An. gambiae) towards anthropophilia and/or endophilia. ...
... The dehydration of C. pipiens resulted in increased blood feeding propensity that was underpinned by alterations in carbohydrates and glycogen [6]. The results were similar in a dry-season ecological study that found alterations in glycerol phosphate, glucose-6-phosphate, and fructose-6-phosphate were important, which was consistent with increased protein or glycogen breakdown or as an indicator of increased pentose phosphate pathway activity [107]. Corroboratively, within the An. ...
... Biochemical and physiological alterations could be theoretically used as markers for the onset of the dry season as they have been utilized to support the position that different adaptive techniques exist in An. coluzzii, where certain metabotype differences represent "strong" aestivation abilities [107]. Likely similar to those that were observed in dry seasons, bouts of desiccation increased the transcript expression for DNA repair, stress response, and reactive oxygen species (ROS) detoxification, as well as the genes that underlie flight, like flightin and myosin [128]. ...
Diseases that are transmitted by mosquitoes are a tremendous health and socioeconomic burden with hundreds of millions of people being impacted by mosquito-borne illnesses annually. Many factors have been implicated and extensively studied in disease transmission dynamics, but knowledge regarding how dehydration impacts mosquito physiology, behavior, and resulting mosquito-borne disease transmission remain underdeveloped. The lapse in understanding on how mosquitoes respond to dehydration stress likely obscures our ability to effectively study mosquito physiology, behavior, and vectorial capabilities. The goal of this review is to develop a profile of factors underlying mosquito biology that are altered by dehydration and the implications that are related to disease transmission.
... The characterization of the biochemical modifications associated with heat stress can be conveniently pictured by metabolomic approaches, as for instance done in Diptera (i.e. D. melanogaster: Cooper et al., 2014; Anopheles sp (Culicidae): Hidalgo et al., 2016;Hidalgo, 2014) and in Hemiptera (Trialeurodes taporariorum (Aleyrodidae): Hendrix and Salvucci, 1998), among others. ...
... In response to climatic or chemical stressors, organisms can trigger a set of metabolic adjustments to challenge cell damages and homeostasis disturbances (Bijlsma and Loeschcke, 2005;Hidalgo et al., 2016Hidalgo et al., , 2018, resulting notably in the production of metabolic end-products like VOCs. VOCs are low molecular weight compounds with relatively high vapor pressure or volatility Abbreviations: PCA, principal component analysis; VOCs, volatile organic compounds. ...
Volatile organic compounds (VOC) produced by microorganisms in response to chemical stressor showed recently increasing attention, because of possible environmental applications. In this work, we aimed to bring the first proof of concept that volatolomic (i.e., VOCs analysis) can be used to determine candidate VOC markers of two soil bacteria strains (Pseudomonas fluorescens SG-1 and Bacillus megaterium Mes11) exposure to pesticides. VOC determination was based on solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Accordingly, we highlighted a set of bacterial VOCs modulated in each strains according to the nature of the pesticide used. Three out these VOCs were specifically modulated in P. fluorescens SG-1 when exposed with two pyrethroid pesticides (deltamethrine and cypermethrine): 2-hexanone; 1,3-ditertbutylbenzene and malonic acid, hexyl 3-methylbutyl ester. Our results thus suggest the possible existence of generic VOC markers of pyrethroids in this strain. Of particular interest, two out of these three VOCs, the 1,3-ditertbutylbenzene and the malonic acid, hexyl 3-methylbutyl ester were found also in B. megaterium Mes11 when exposed with cypermethrine. This result highlighted the possible existence of interspecific VOC markers of pyrethroid in these two bacteria. Altogether, our work underlined the relevance of volatolomic to detect signatures of pesticides exposure in microorganisms and more generally to microbial ecotoxicology. Based on these first results, considerations of volatolomics for the chemical risk assessment in environment such as soils can be indirectly explored in longer terms.
