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Yvan Capowiez - One of the best experts on this subject based on the ideXlab platform.
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how lasting are the effects of pesticides on earwigs a study based on energy metabolism body weight and morphometry in two generations of Forficula auricularia from apple orchards
Science of The Total Environment, 2021Co-Authors: Adrien Le Navenant, Magali Rault, Yvan Capowiez, Corinne Brouchoud, Séverine SuchailAbstract:Widespread use of pesticides to control pests is the dominant system in conventional apple orchards. To avoid adverse side effects, there is a growing interest in promoting alternative methods including biological control based on the use of natural enemies. The European earwig Forficula auricularia L. (Dermaptera: Forficuidae) is an effective predator in apple orchards. Pesticide pressure has been shown to divert energy resources which could have a negative impact on life history traits. In this study we assessed (i) whether variations in pesticide exposure could differentially impact energy reserves, body weight and morphometric parameters of F. auricularia, and (ii) whether these effects persist into the next generation reared under optimal conditions. Individuals from the first generation were collected in late October from organic, IPM and conventional orchards. The next generation was obtained under a rearing program, in the absence of pesticide exposure. Earwigs collected from conventional orchards exhibited lower values for all morphometric parameters compared to those collected in organic orchards. However, a relaxed period without pesticide exposure (in autumn) appears to have allowed the females to recover their energy reserves to ensure reproduction and maternal care. Glycogen contents were the reserves that were more easily restored. However, probably due to the rearing conditions (food ad libitum), all the earwigs from the second generation exhibited higher body weights and energy reserves than their parents.
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Metabolic mechanisms and acetylcholinesterase sensitivity involved in tolerance to chlorpyrifos-ethyl in the earwig Forficula auricularia.
Chemosphere, 2019Co-Authors: Adrien Le Navenant, Yvan Capowiez, Myriam Siegwart, Sandrine Maugin, Magali RaultAbstract:Apple orchards are highly treated crops, in which organophosphorus (OP) are among the most heavily sprayed insecticides. These pesticides are toxic to non-target arthropods and their repeated use increases the risk of resistance. We studied mechanisms involved in tolerance and resistance to OP insecticides in the earwig Forficula auricularia, an effective generalist predator in pomefruit orchards. Adult earwigs were sampled in three apple orchards managed under contrasting strategies: conventional, Integrated Pest Management, and organic. The threshold activities of enzyme families involved in pesticides tolerance: Glutathione-S-transferases (GSTs) and Carboxylesterases (CbEs) were measured in earwig extracts. Acetylcholinesterase (AChE) was monitored as a toxicological endpoint. Variations in these activities were assessed prior to and after exposure to chlorpyrifos-ethyl at the normal application rate. We observed that the mortality of earwigs exposed to chlorpyrifos-ethyl depended on the management strategy of orchards. Significantly lower mortality was seen in individuals sampled from conventional orchard. The basal activities of CbEs and GSTs of collected organisms were higher in conventional orchard. After in vivo exposure, AChE activity appeared to be inhibited in surviving males with no difference between orchards. However an in vitro inhibition trial with chlorpyrifos-oxon showed that AChE from earwigs collected in organic and IPM orchards were more sensitive than from conventional ones. These observations support the hypothesis of a molecular target modification in AChE and highlight the possible role of CbEs in effective protection of AChE. Our findings suggest that the earwigs with a high historic level of insecticide exposure could acquire resistance to chlorpyrifos-ethyl.
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An exploratory study of energy reserves and biometry as potential tools for assessing the effects of pest management strategies on the earwig, Forficula auricularia L
Environmental Science and Pollution Research, 2018Co-Authors: Séverine Suchail, Adrien Le Navenant, Yvan Capowiez, Alain Thiéry, Magali RaultAbstract:Apple orchards are heavily treated crops and some sprayed insecticides are recognized to have toxic effects on non-target arthropods. Earwigs are important natural enemies in pip-fruit orchards and contribute to the biological control of aphids. In addition, due to their ease of capture and identification, they are an interesting potential bioindicator of the possible detrimental effects of different orchard management strategies. In this study, we measured the energy reserves and some morphological traits of Forficula auricularia L. sampled in apple orchards under management strategies (organic versus integrated pest management (IPM)). We observed a significant decrease in mass (22 to 27%), inter-eye width (3%), and prothorax width (2 to 5%) in earwigs from IPM compared to organic orchards. Energy body reserves also confirmed these results with a significant decrease of 48% in glycogen and 25 to 42% in lipid content in earwigs from IPM compared to organic orchards. However, the protein content was approximately 70% higher in earwigs from IPM than in organic orchards. Earwigs sampled in IPM orchards may adapt to minimize the adverse toxic effects of pesticide treatments using a large number of strategies, which are reflected in changes to their energy reserves. These strategies could, in turn, influence the population dynamics of natural enemies and impair their role in the biological control of pests in apple orchards.
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Report on the life history traits of the generalist predator Forficula auricularia (Dermaptera: Forficulidae) in organic apple orchards in southeastern France
Canadian Entomologist, 2017Co-Authors: Hazem Dib, Benoit Sauphanor, Yvan CapowiezAbstract:The aim of this paper is to provide detailed data on the reproduction of the European earwig Forficula auricularia Linnaeus (Dermaptera: Forficulidae) under natural conditions. We also describe its spring field population structure and dynamics in organic apple orchards in southeastern France using artificial and natural shelters. Two nymph cohorts could be distinguished in a laboratory reproduction study. The first brood, following the first egg-laying event in late November, had significantly higher pre-imaginal survival (1.74-fold) than the second brood in early April. The egg phase was the most vulnerable with a higher mortality rate in the first brood than the second. Independent of brood number, nymphal survival increased from second nymphal instars (N2) onwards with values higher than 96%. In orchards, N3 were generally observed in natural and artificial shelters from the end of April to mid-June. N4 was the most abundant life stage sampled and the only stage present at the majority of sampling dates, especially from early May onwards. Beginning in June, the abundance of new adults of a given year gradually increased especially in the artificial shelters. This descriptive study can now be used to develop phenological models aimed at limiting earwig mortality due to horticultural management practices and increasing their predation level in conservative or augmentative approaches.
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The feasibility and efficacy of early-season releases of a generalist predator (Forficula auricularia L.) to control populations of the RAA (Dysaphis plantaginea Passerini) in Southeastern France
Bulletin of Entomological Research, 2016Co-Authors: Hazem Dib, Marie Jamont, Benoit Sauphanor, Yvan CapowiezAbstract:Augmentative biological control is not commonly used in commercial orchards. We used an exclusion system to evaluate the potential of early-season releases of the European earwig (Forficula auricularia L., Dermaptera: Forficulidae) for control of the rosy apple aphid (Dysaphis plantaginea Passerini, Hemiptera: Aphididae) in the spring of 2009 in two pesticide-free apple orchards. In order to conduct this experiment we successfully reared earwigs with a high survival rate of nymphs (more than 96%) which may have commercial application. There were three treatments in the study: (i) a 'release treatment' where we confined the released earwigs in the canopy by using a barrier system; (ii) an 'exclusion treatment' where we blocked free access of earwigs into the canopy using the same barrier system; and (iii) a 'control treatment' that represented the natural situation. Contrary to expectations, earwig releases did not reduce D. plantaginea populations. In general, the abundance of natural enemies and their groups did not differ significantly among treatments, except for earwigs. We observed that the exclusion systems we used successfully kept both earwigs and ants away from tree canopies; total numbers on trees in the 'exclusion treatment' were significantly lower than on the other two treatments. Due to the complexity and difficulty of evaluating augmentative releases of natural enemies in open orchard conditions, we conclude that new technical approaches to control site conditions are needed when conducting such studies
Hazem Dib - One of the best experts on this subject based on the ideXlab platform.
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does combining Forficula auricularia l dermaptera forficulidae with harmonia axyridis pallas coleoptera coccinellidae enhance predation of rosy apple aphid dysaphis plantaginea passerini hemiptera aphididae
Biological Control, 2020Co-Authors: Hazem Dib, Myriam Siegwart, Thomas Delattre, Marie Perrin, Claire LavigneAbstract:Abstract A good knowledge of interactions between natural enemy species is necessary for effective implementation of biological control programmes. This laboratory study aimed at assessing the outcome of intraguild interactions between two generalist predators frequently observed in the colonies of the rosy apple aphid (RAA), Dysaphis plantaginea Passerini (Hemiptera: Aphididae). The level of complementarity between these two species was estimated by the comparison of their individual and combined predation on RAA. Predation by 1st (H1) to 4th (H4) instar larvae of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) and 3rd (F3) and 4th (F4) instar nymphs of Forficula auricularia L. (Dermaptera: Forficulidae) was evaluated for 24 h in Petri dishes using seven different densities (5, 10, 25, 50, 75, 100 and 200) of 3rd instar nymphs of RAA. Both predator species were more voracious as their age increased. The satiation level, i.e. the highest number of consumed RAA, reached on average of 17.8, 36.3, 49.4, 79.6, 62.9 and 84.3 aphids per day for H1, H2, H3, H4, F3 and F4, respectively. In the combined treatments, there was little evidence of intraguild predation. Only 2.9% of H1 and H2 died or disappeared at low RAA densities (≤25 aphids). At the non-limiting RAA density of 200, we observed a slight agonistic interaction with 7.9% less RAA consumption when the two predators were in the same arena than the sum of their individual consumptions. However, this effect was very small and was largely outweighed by the benefits of using these two predators in combination to increase prey consumption. For the other six RAA densities, predators in combination consumed a high proportion (>90%) of RAA. Our results point to the use of combinations of these two predator species, especially of their oldest instars, as promising aphidophagous candidates in early spring against RAA.
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Report on the life history traits of the generalist predator Forficula auricularia (Dermaptera: Forficulidae) in organic apple orchards in southeastern France
Canadian Entomologist, 2017Co-Authors: Hazem Dib, Benoit Sauphanor, Yvan CapowiezAbstract:The aim of this paper is to provide detailed data on the reproduction of the European earwig Forficula auricularia Linnaeus (Dermaptera: Forficulidae) under natural conditions. We also describe its spring field population structure and dynamics in organic apple orchards in southeastern France using artificial and natural shelters. Two nymph cohorts could be distinguished in a laboratory reproduction study. The first brood, following the first egg-laying event in late November, had significantly higher pre-imaginal survival (1.74-fold) than the second brood in early April. The egg phase was the most vulnerable with a higher mortality rate in the first brood than the second. Independent of brood number, nymphal survival increased from second nymphal instars (N2) onwards with values higher than 96%. In orchards, N3 were generally observed in natural and artificial shelters from the end of April to mid-June. N4 was the most abundant life stage sampled and the only stage present at the majority of sampling dates, especially from early May onwards. Beginning in June, the abundance of new adults of a given year gradually increased especially in the artificial shelters. This descriptive study can now be used to develop phenological models aimed at limiting earwig mortality due to horticultural management practices and increasing their predation level in conservative or augmentative approaches.
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The feasibility and efficacy of early-season releases of a generalist predator (Forficula auricularia L.) to control populations of the RAA (Dysaphis plantaginea Passerini) in Southeastern France
Bulletin of Entomological Research, 2016Co-Authors: Hazem Dib, Marie Jamont, Benoit Sauphanor, Yvan CapowiezAbstract:Augmentative biological control is not commonly used in commercial orchards. We used an exclusion system to evaluate the potential of early-season releases of the European earwig (Forficula auricularia L., Dermaptera: Forficulidae) for control of the rosy apple aphid (Dysaphis plantaginea Passerini, Hemiptera: Aphididae) in the spring of 2009 in two pesticide-free apple orchards. In order to conduct this experiment we successfully reared earwigs with a high survival rate of nymphs (more than 96%) which may have commercial application. There were three treatments in the study: (i) a 'release treatment' where we confined the released earwigs in the canopy by using a barrier system; (ii) an 'exclusion treatment' where we blocked free access of earwigs into the canopy using the same barrier system; and (iii) a 'control treatment' that represented the natural situation. Contrary to expectations, earwig releases did not reduce D. plantaginea populations. In general, the abundance of natural enemies and their groups did not differ significantly among treatments, except for earwigs. We observed that the exclusion systems we used successfully kept both earwigs and ants away from tree canopies; total numbers on trees in the 'exclusion treatment' were significantly lower than on the other two treatments. Due to the complexity and difficulty of evaluating augmentative releases of natural enemies in open orchard conditions, we conclude that new technical approaches to control site conditions are needed when conducting such studies
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Individual and combined effects of the generalist Forficula auricularia and the specialist Episyrphus balteatus on Dysaphis plantaginea - are two predators better than one?
Entomologia Experimentalis et Applicata, 2016Co-Authors: Hazem Dib, Marie Jamont, Benoit Sauphanor, Yvan CapowiezAbstract:The interactions between specialist and generalist natural enemies could affect the success of biological pest control, especially in augmentation programmes. The aim of this laboratory study was to quantitate the individual and combined effects of the generalist predator Forficula auricularia L. (Dermaptera: Forficulidae) and the specialist Episyrphus balteatus De Geer (Diptera: Syrphidae) on the population growth of the rosy apple aphid (RAA), Dysaphis plantaginea Passerini (Hemiptera: Aphididae). The experiment was carried out using apple seedlings with five levels of initial RAA infestation. In most cases, both predator species (alone and in combination) were able to reduce RAA densities or to keep them at their initial level. This suppression effect was greater when RAA densities were low and resulted in near-complete mortality of the RAA colony after 4-6 days. Without predators, RAA population size almost doubled within 10 days, whereas with predators, RAA population size was reduced by about 20 (alone) and 50% (in combination). Although RAA numbers in the two-predators treatment were ca. 81% of RAA numbers in the one-predator treatment for pooled numbers across dates and densities, the difference between the two treatments was not significant. Some predator mortality occurred with first and second instars of the syrphid larvae and only at the two lowest initial RAA infestation levels. This mortality may be explained by inadequate food supply, intraguild predation (IGP) (in 13.3% of the possible cases), or both. However, the incidence of IGP under natural conditions could be even less frequent, as both predators were never observed on the same leaf.
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predation potency and intraguild interactions between generalist Forficula auricularia and specialist episyrphus balteatus predators of the rosy apple aphid dysaphis plantaginea
Biological Control, 2011Co-Authors: Marie Jamont, Hazem Dib, Benoit Sauphanor, Yvan CapowiezAbstract:Abstract To evaluate whether aphid antagonists are suitable targets for biological approaches to control aphid populations, their voracity and intraguild interactions must first be elucidated. The aim of this laboratory study was to compare two predators of the rosy apple aphid (RAA) Dysaphis plantaginea : the generalist Forficula auricularia and the specialist Episyrphus balteatus . Predation by 2nd and 3rd instar larvae of E. balteatus and 3rd and 4th instar nymphs of F. auricularia was evaluated individually and in combination for 24 h in Petri dishes. Five different densities (25, 50, 75, 100 and 200) of 1st or 3rd instar nymphs of RAA were incubated at three different temperatures (15, 20 and 25 °C). Overall, the older life-stages of both predator species were more voracious than younger individuals. The two predator species did not negatively interact. Instead, when the RAA density was not limiting they had an additive effect. Although the predators consumed significantly higher numbers of RAA when the younger life-stages were offered, they fed more efficiently on the older life-stages of RAA with consumption of 1.8- to 2.7-fold higher biomass. In general, the most RAA were consumed at 20 °C. Syrphids consumed more RAA at 15 °C than at 25 °C whereas earwigs consumed slightly more aphids at 25 °C than at 15 °C. Overall, the two predators consumed a constant proportion of RAA at the first four RAA densities until reaching satiation. This finding suggests that in theory they would be effective in regulating RAA numbers in early spring when field RAA populations are beginning to build up. The potency of both predators, alone or in combination, should now be tested for augmentative approaches in semi-field and field studies.
Magali Rault - One of the best experts on this subject based on the ideXlab platform.
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how lasting are the effects of pesticides on earwigs a study based on energy metabolism body weight and morphometry in two generations of Forficula auricularia from apple orchards
Science of The Total Environment, 2021Co-Authors: Adrien Le Navenant, Magali Rault, Yvan Capowiez, Corinne Brouchoud, Séverine SuchailAbstract:Widespread use of pesticides to control pests is the dominant system in conventional apple orchards. To avoid adverse side effects, there is a growing interest in promoting alternative methods including biological control based on the use of natural enemies. The European earwig Forficula auricularia L. (Dermaptera: Forficuidae) is an effective predator in apple orchards. Pesticide pressure has been shown to divert energy resources which could have a negative impact on life history traits. In this study we assessed (i) whether variations in pesticide exposure could differentially impact energy reserves, body weight and morphometric parameters of F. auricularia, and (ii) whether these effects persist into the next generation reared under optimal conditions. Individuals from the first generation were collected in late October from organic, IPM and conventional orchards. The next generation was obtained under a rearing program, in the absence of pesticide exposure. Earwigs collected from conventional orchards exhibited lower values for all morphometric parameters compared to those collected in organic orchards. However, a relaxed period without pesticide exposure (in autumn) appears to have allowed the females to recover their energy reserves to ensure reproduction and maternal care. Glycogen contents were the reserves that were more easily restored. However, probably due to the rearing conditions (food ad libitum), all the earwigs from the second generation exhibited higher body weights and energy reserves than their parents.
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Sublethal exposure to deltamethrin impairs maternal egg care in the European earwig Forficula auricularia
Chemosphere, 2020Co-Authors: Joël Meunier, Magali Rault, Juliette Dufour, Sophie Van Meyel, Charlotte LécureuilAbstract:The application of pesticides typically leads to lethal and sublethal exposure of non-target insects. Whereas our current understanding of these sublethal effects typically focuses on reproductive and physiological parameters, recent works emphasize that sublethal effects on behaviors such as maternal care could be of major importance in non-target species. However, it remained unknown whether these sublethal effects occur in insects. Here, we tested if exposure to sublethal doses of deltamethrin - a pyrethroid insecticide commonly used in crops - alters the expression of maternal egg care in females of the European earwig Forficula auricularia, a predator insect and pest control. Our results first reveal that deltamethrin exposure impaired the expression of three forms of maternal egg care: It decreased the likelihood of mothers to gather their otherwise scattered clutch of eggs, increased the time during which the female abandoned the clutch after a predator attack and reduced egg grooming duration. These sublethal effects did not reflect a lower activity of deltamethrin-exposed females, as these females increased their expression of self-grooming, and deltamethrin exposure did not affect females’ exploration and mobility. Finally, we found that the negative effects of deltamethrin on egg care did not modify egg development, hatching rate and juvenile weight, possibly due to the transient effects of deltamethrin on maternal behaviors. Overall, our results reveal that sublethal exposure to a pesticide may diminish maternal egg care in a natural pest control and call for the integration of this measurement in assays on pesticides application.
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Metabolic mechanisms and acetylcholinesterase sensitivity involved in tolerance to chlorpyrifos-ethyl in the earwig Forficula auricularia.
Chemosphere, 2019Co-Authors: Adrien Le Navenant, Yvan Capowiez, Myriam Siegwart, Sandrine Maugin, Magali RaultAbstract:Apple orchards are highly treated crops, in which organophosphorus (OP) are among the most heavily sprayed insecticides. These pesticides are toxic to non-target arthropods and their repeated use increases the risk of resistance. We studied mechanisms involved in tolerance and resistance to OP insecticides in the earwig Forficula auricularia, an effective generalist predator in pomefruit orchards. Adult earwigs were sampled in three apple orchards managed under contrasting strategies: conventional, Integrated Pest Management, and organic. The threshold activities of enzyme families involved in pesticides tolerance: Glutathione-S-transferases (GSTs) and Carboxylesterases (CbEs) were measured in earwig extracts. Acetylcholinesterase (AChE) was monitored as a toxicological endpoint. Variations in these activities were assessed prior to and after exposure to chlorpyrifos-ethyl at the normal application rate. We observed that the mortality of earwigs exposed to chlorpyrifos-ethyl depended on the management strategy of orchards. Significantly lower mortality was seen in individuals sampled from conventional orchard. The basal activities of CbEs and GSTs of collected organisms were higher in conventional orchard. After in vivo exposure, AChE activity appeared to be inhibited in surviving males with no difference between orchards. However an in vitro inhibition trial with chlorpyrifos-oxon showed that AChE from earwigs collected in organic and IPM orchards were more sensitive than from conventional ones. These observations support the hypothesis of a molecular target modification in AChE and highlight the possible role of CbEs in effective protection of AChE. Our findings suggest that the earwigs with a high historic level of insecticide exposure could acquire resistance to chlorpyrifos-ethyl.
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An exploratory study of energy reserves and biometry as potential tools for assessing the effects of pest management strategies on the earwig, Forficula auricularia L
Environmental Science and Pollution Research, 2018Co-Authors: Séverine Suchail, Adrien Le Navenant, Yvan Capowiez, Alain Thiéry, Magali RaultAbstract:Apple orchards are heavily treated crops and some sprayed insecticides are recognized to have toxic effects on non-target arthropods. Earwigs are important natural enemies in pip-fruit orchards and contribute to the biological control of aphids. In addition, due to their ease of capture and identification, they are an interesting potential bioindicator of the possible detrimental effects of different orchard management strategies. In this study, we measured the energy reserves and some morphological traits of Forficula auricularia L. sampled in apple orchards under management strategies (organic versus integrated pest management (IPM)). We observed a significant decrease in mass (22 to 27%), inter-eye width (3%), and prothorax width (2 to 5%) in earwigs from IPM compared to organic orchards. Energy body reserves also confirmed these results with a significant decrease of 48% in glycogen and 25 to 42% in lipid content in earwigs from IPM compared to organic orchards. However, the protein content was approximately 70% higher in earwigs from IPM than in organic orchards. Earwigs sampled in IPM orchards may adapt to minimize the adverse toxic effects of pesticide treatments using a large number of strategies, which are reflected in changes to their energy reserves. These strategies could, in turn, influence the population dynamics of natural enemies and impair their role in the biological control of pests in apple orchards.
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impact of insecticide exposure on the predation activity of the european earwig Forficula auricularia
Environmental Science and Pollution Research, 2015Co-Authors: Laure Malagnoux, Yvan Capowiez, Magali RaultAbstract:The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (−33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (−59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.
M Vancassel - One of the best experts on this subject based on the ideXlab platform.
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maternal attendance and the maintenance of family groups in common earwigs Forficula auricularia a field experiment
Ecological Entomology, 2007Co-Authors: Mathias Kölliker, M VancasselAbstract:1. Understanding the evolution of subsocial behaviour and parental care requires experimental tests of the functional significance of such behaviours and the role of tending parents in the maintenance of family groups. Studies in subsocial insects addressing these issues experimentally and in the field are still relatively rare. 2. In such a field experiment, it is demonstrated here that the presence of tending females enhances the maintenance of family groups in common earwigs, Forficula auricularia (Dermaptera; Forficulidae). Experimental removal of tending mothers resulted in substantially decreased recovery of occupied nest burrows and larvae. This effect may have been because of decreased survival among experimental larvae, although a possible role for enhanced larval dispersal could not be fully ruled out. 3. Experimental (motherless) larvae were partly observed in family groups with a tending female, in both experimental and control nest burrows, suggesting that these larvae had been adopted by family groups moving to new nest burrows, and/or that experimental larvae may have actively joined other family groups. 4. This study demonstrates under field conditions the functional importance of maternal attendance for the maintenance of family groups in common earwigs, and suggests that adoption and clutch-joining are factors affecting the social structure of this species.
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analysis of a contact zone in the Forficula auricularia l dermaptera forficulidae species complex in the pyrenean mountains
Heredity, 2000Co-Authors: S Guillet, Annie Guiller, J Deunff, M VancasselAbstract:Analysis of a contact zone in the Forficula auricularia L. (Dermaptera: Forficulidae) species complex in the Pyrenean Mountains
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multiple introductions of the Forficula auricularia species complex dermaptera forficulidae in eastern north america
Canadian Entomologist, 2000Co-Authors: S Guillet, Nathalie Josselin, M VancasselAbstract:L'etude de neuf populations du complexe d'especes de perce-oreille Europeen, Forficula auricularia L., localisees a l'est de l'Amerique du Nord, a revele la presence de deux especes jumelles recemment identifiees en tant qu'espece A et espece B. Une analyse mitochondriale, basee sur le polymorphisme de restriction observe pour les regions 16S rRNA et cytochrome oxydase, a permis d'identifier et de distinguer rapidement ces deux especes. De plus, la concordance de ces donnees mitochondriales avec une diagnose biologique basee sur les dates et le nombre de pontes dans chaque population a revele que les especes A et B occupent des habitats differents. Ces observations concordent avec l'hypothese selon laquelle les deux especes auraient ete introduites a de multiples reprises sur la cote Atlantique de l'Amerique du Nord, l'espece la mieux adaptee ayant ete selectionnee dans chaque habitat.
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molecular and reproductive characterization of sibling species in the european earwig Forficula auricularia
Evolution, 1998Co-Authors: M Vancassel, Thierry Wirth, Rene Le Guellec, Michel VeuilleAbstract:: The European earwig (Forficula auricularia) was formerly thought to present a mosaic of populations differing in their reproductive biology. We show that it is comprised of two as yet unrecognized sibling species. The molecular divergence between the two species, for a 627-bp amplified fragment overlapping the COI and COII mitochondrial loci, is six times larger than intraspecific variation. A species with two clutches a year lives predominantly in lowland and oceanic European habitats. A species with one clutch a year-except in the Mediterranean area where it has two clutches-lives predominantly in highland and continental European habitats. They both invaded North America during the 20th century, respectively, from the west and the east coasts, with no apparent mixing of their populations. The two species can occur in sympatry in Europe and are reproductively isolated by nearly complete failure to produce F1 hybrids.
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the eggs of Forficula auricularia l dermaptera forficulidae ultrastructure and resistance to low and high temperatures
Canadian Journal of Zoology, 1991Co-Authors: Georges Chauvin, M Vancassel, Claude Hamon, Guy VannierAbstract:The morphology, ultrastructure, and resistance to low and high temperatures of the fertilized egg of Forficula auricularia were studied both before and after water absorption. The increase in volum...
Jeanclaude Walser - One of the best experts on this subject based on the ideXlab platform.
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De Novo Transcriptome Hybrid Assembly and Validation in the European Earwig (Dermaptera, Forficula auricularia)
2016Co-Authors: Anne C Roulin, Samuel Pichon, Roberto Arbore, Jeanclaude WalserAbstract:Background: The European earwig (Forficula auricularia) is an established system for studies of sexual selection, social interactions and the evolution of parental care. Despite its scientific interest, little knowledge exists about the species at the genomic level, limiting the scope of molecular studies and expression analyses of genes of interest. To overcome these limitations, we sequenced and validated the transcriptome of the European earwig. Methodology and Principal Findings: To obtain a comprehensive transcriptome, we sequenced mRNA from various tissues and developmental stages of female and male earwigs using Roche 454 pyrosequencing and Illumina HiSeq. The reads were de novo assembled independently and screened for possible microbial contamination and repeated elements. The remaining contigs were combined into a hybrid assembly and clustered to reduce redundancy. A comparison with the eukaryotic core gene dataset indicates that we sequenced a substantial part of the earwig transcriptome with a low level of fragmentation. In addition, a comparative analysis revealed that more than 8,800 contigs of the hybrid assembly show significant similarity to insect-specific proteins and those were assigned for Gene Ontology terms. Finally, we established a quantitative PCR test for expression stability using commonly used housekeeping genes and applied the method to five homologs of known sex-biased genes of the honeybee. The qPCR pilot study confirmed sex specific expression and also revealed significant expression differences between the brain and antenna tissue samples
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multiple paternity and mating group size in the european earwig Forficula auricularia
Ecological Entomology, 2015Co-Authors: Lina Sandrin, Shirley Raveh, Jeanclaude Walser, Joël Meunier, Mathias KöllikerAbstract:The patterns of multiple paternity among the progeny of females are key properties of genetic mating systems. Female multiple mating should evolve due to direct or indirect benefits, but it may also partly be driven by the encounter rate with different potential mates. 2. In this study this hypothesis was experimentally tested in the European earwig (Forficula auricularia L.) by establishing experimental mating groups that differed in the number of males and females (i.e. density). The number of sires and mean sibling relatedness in each clutch were estimated using microsatellite-based paternity analysis. 3. As predicted, the mean number of sires per clutch was significantly increased, and sibling relatedness decreased, in the higher density treatment where more potential male mates were available. This change was less than proportional to the number of males in the mating groups, indicating that mechanisms limiting multiple paternity in large mating groups were involved. There were no significant relationships between female reproductive success or male siring success with morphology (body size, weight, and forceps size). 4. The present results show that multiple paternity in F. auricularia clutches is partly determined by the availability of male mates and suggest that this effect is modulated by mechanisms in males and/or females that limit multiple paternity.
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de novo transcriptome hybrid assembly and validation in the european earwig dermaptera Forficula auricularia
PLOS ONE, 2014Co-Authors: Anne C Roulin, Mathias Kölliker, Samuel Pichon, Roberto Arbore, Simone Kuhnbuhlmann, Jeanclaude WalserAbstract:Background The European earwig (Forficula auricularia) is an established system for studies of sexual selection, social interactions and the evolution of parental care. Despite its scientific interest, little knowledge exists about the species at the genomic level, limiting the scope of molecular studies and expression analyses of genes of interest. To overcome these limitations, we sequenced and validated the transcriptome of the European earwig. Methodology and Principal Findings To obtain a comprehensive transcriptome, we sequenced mRNA from various tissues and developmental stages of female and male earwigs using Roche 454 pyrosequencing and Illumina HiSeq. The reads were de novo assembled independently and screened for possible microbial contamination and repeated elements. The remaining contigs were combined into a hybrid assembly and clustered to reduce redundancy. A comparison with the eukaryotic core gene dataset indicates that we sequenced a substantial part of the earwig transcriptome with a low level of fragmentation. In addition, a comparative analysis revealed that more than 8,800 contigs of the hybrid assembly show significant similarity to insect-specific proteins and those were assigned for Gene Ontology terms. Finally, we established a quantitative PCR test for expression stability using commonly used housekeeping genes and applied the method to five homologs of known sex-biased genes of the honeybee. The qPCR pilot study confirmed sex specific expression and also revealed significant expression differences between the brain and antenna tissue samples. Conclusions By employing two different sequencing approaches and including samples obtained from different tissues, developmental stages, and sexes, we were able to assemble a comprehensive transcriptome of F. auricularia. The transcriptome presented here offers new opportunities to study the molecular bases and evolution of parental care and sociality in arthropods.