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The reasons why some individuals are solitary, and others gregarious are the subject of ongoing debate as we seek to understand the emergence of sociality. Recent studies suggest that the expression of aggregation behaviors may be linked to the gut microbiota of the host. Here, we tested this hypothesis in females of the European earwig. This insect is ideal for addressing this question, as adults both naturally vary in the degree to which they live in groups and show interindividual variation in their gut microbial communities. We video-tracked 320 field-sampled females to quantify their natural variation in aggregation and then tested whether the most and least gregarious females had different gut microbiota. We also compared the general activity, boldness, body size, and body condition of these females and examined the association between each of these traits and the gut microbiota. Contrary to our predictions, we found no difference in the gut microbiota between the most and least gregarious females. There was also no difference in activity, boldness, and body condition between these two types of females. Independent of aggregation, gut microbiota was overall associated with female body condition, but not with any of our other measurements. Overall, these results demonstrate that a host's gut microbiota is not necessarily a major driver or a consequence of aggregation behavior in species with inter-individual variation in group living and call for future studies to investigate the determinants and role of gut microbiota in earwigs. [ABSTRACT FROM AUTHOR]

Abstract Convergent evolution is a common phenomenon, independently leading to similar morphologies in different evolutionary lineages. Often similar functional demands drive convergent evolution. One example is the independent evolution of grasping structures in different lineages of Euarthropoda, though the exact morphology of these grasping structures varies significantly. In this study, we investigated grasping apparatuses with two movable counteracting structures as well as some related structures, exemplified by the stylets (compound structures of mouthparts) of aphidlion-like larvae (part of Neuroptera or lacewings) and the cerci of immature earwigs (Dermaptera). For the stylets of aphidlion-like larvae, studies have pointed to a significant loss in morphological diversity in the last 100 million years. We used quantitative morphology to evaluate if a similar process has also occurred in the cerci of earwigs. The cerci of extant immature earwigs exhibit two distinct types of morphologies in the modern fauna: elongated cerci divided into several ringlets with a feeler-type function, and pincer-like stout cerci. In some fossil immature earwigs, however, the cerci are generally elongated but undivided and roughly occupy the morphospace between those of the two modern cerci types; hence this fossil cerci morphology appears to have been lost. To some extent, a comparable loss is also found in certain lacewing larvae. Outgroup comparisons suggest that the morphologies no longer present today are in fact not ancestral, but instead specialised, hence their loss is possibly resulting from disruptive evolution in earwigs as well as lacewings. We discuss the possible functions of these specialised grasping structures.

Convergent evolution is a common phenomenon, independently leading to similar morphologies in different evolutionary lineages. Often similar functional demands drive convergent evolution. One example is the independent evolution of grasping structures in different lineages of Euarthropoda, though the exact morphology of these grasping structures varies significantly. In this study, we investigated grasping apparatuses with two movable counteracting structures as well as some related structures, exemplified by the stylets (compound structures of mouthparts) of aphidlion-like larvae (part of Neuroptera or lacewings) and the cerci of immature earwigs (Dermaptera). For the stylets of aphidlion-like larvae, studies have pointed to a significant loss in morphological diversity in the last 100 million years. We used quantitative morphology to evaluate if a similar process has also occurred in the cerci of earwigs. The cerci of extant immature earwigs exhibit two distinct types of morphologies in the modern fauna: elongated cerci divided into several ringlets with a feeler-type function, and pincer-like stout cerci. In some fossil immature earwigs, however, the cerci are generally elongated but undivided and roughly occupy the morphospace between those of the two modern cerci types; hence this fossil cerci morphology appears to have been lost. To some extent, a comparable loss is also found in certain lacewing larvae. Outgroup comparisons suggest that the morphologies no longer present today are in fact not ancestral, but instead specialised, hence their loss is possibly resulting from disruptive evolution in earwigs as well as lacewings. We discuss the possible functions of these specialised grasping structures. [ABSTRACT FROM AUTHOR]

The Dermaptera is a polyneopteran order with > 2,000 described species from mainly tropical, subtropical, and warm temperate regions. More than 310 species of the Dermaptera belonging to nine families have been reported from the Indian subcontinent (India, Pakistan, Nepal, Bhutan, Bangladesh and Sri Lanka) as a result of the extensive work of Gyanendra Kumar Srivastava. Embracing environmental and climatic heterogeneity, the Indian subcontinent is an intersection of multiple faunal regions and includes several dermapteran groups of special interest. To restart the studies on the Dermaptera of this region, which has been stagnant for a decade, this paper includes a beginner's guide for collecting and identifying Dermaptera, together with a brief summary of recent advances in their classification and phylogeny. [ABSTRACT FROM AUTHOR]

Orthopteroidea is an ecologically diverse group of incompletely transformed insects that includes several insect orders similar in development and structure. Many species from Dermaptera, Orthoptera, Mantodea, and Blattodea are sensitive to anthropogenic influences and are indicators of the external environment. Some species cause damage to agriculture and forestry; others are inhabitants of human dwellings and pests of food supplies. The aim of this study is to describe fauna of some orders of Orthopteroidea in the Republic of Mordovia, in the central part of European Russia. This study was conducted in April–October 1971, 1984, 1995, 1996, 1998, 2000, 2001, and 2004–2023. All possible habitats were studied using a variety of methods (entomological traps, pitfall traps, pan traps, etc.). An acoustic method of species identification was also used. For each observation, the coordinates of location, abundance, and dates were recorded. The dataset contains 4865 occurrences. In total, 16,644 specimens of Orthopteroidea were studied. The dataset contains 71 species including Dermaptera (4), Orthoptera (62), Mantodea (1), and Blattodea (4). Of these, 13 species are identified for the first time in the region; these mainly inhabit steppe areas. The presence of two Orthoptera species has not been confirmed yet during our studies; these species are noted in this paper according an old published paper. The biodiversity of Mordovia includes 73 species from four orders. The biology of numerous species, their seasonal dynamics, and some descriptions of biotopes and number of new species are described. Dataset:  https://doi.org/10.15468/cmr3yy. Dataset License: Creative Commons Attribution (CC-BY) 4.0 License [ABSTRACT FROM AUTHOR]

New Dermaptera taxa (one new genus and four new species) are reported from amber pieces proceeding from Mina Los Pocitos near Simojovel de Allende, Chiapas. The amber pieces were collected in the lower Miocene Mazantic Shale, including well-preserved earwigs, with only one antecedent for this insect group in the Mexican amber. The presence of this kind of insects supports the paleoenvironmental interpretation for the Mazantic Shale amber as of a humid forest. [ABSTRACT FROM AUTHOR]

Simple Summary: Italy plays a central role in the research on Europe's biogeography because of its position in the middle of the Mediterranean, which is a global hotspot of diversity. This study investigated how present patterns of earwig species richness and composition in Italy are affected by climatic, geographical, and historical factors. Earwig richness does not decrease from the base to the tip of the Italian peninsula, which contrasts with the so-called 'peninsula effect'. However, richness does not increase southward either, suggesting that southern regions did not play a crucial role as a refuge during Pleistocene glaciations. Inter-regional similarities in species composition between regions is more influenced by their geographical proximity than climatic similarity, although richness is positively correlated with precipitation, in accordance with earwig preferences for humid conditions. The similarity in species composition with central European fauna decreases southward, indicating possible exchanges between central Europe and Italy. The majority of the earwigs of the Italian fauna are either widespread across Europe and the Palearctic, or confined to the main Italian mountain ranges, that is, the Alps and the Apennines. The isolation of ancient earwig populations on mountains resulted in the development of a high proportion of endemics, making the Italian earwig fauna one of the richest in Europe. Placed in the center of the Mediterranean biodiversity hotspot, Italy plays a central role for the study of Europe's biogeography. In this paper, the influence of climatic, spatial, and historical factors on current patterns of variation in earwig species richness and composition is investigated. The Italian earwig fauna is mainly composed of species which are either widely distributed in Europe and the Palearctic region or that are endemic to the Alps and the Apennines. Variation in species richness does not follow any obvious geographical patterns, but a positive influence of precipitation on richness is consistent with earwig preferences for humid climates. European mainland territories did not contribute substantially to the current biodiversity of Italian earwigs, which explains the lack of a distinct peninsula effect, although a southward decrease in similarity with the central European fauna was observed. However, southern areas did not exert a pivotal role during Pleistocene glaciations in determining current patterns of species richness. Variation in species composition among Italian regions can be mostly explained by geographical proximity, while climatic differences and historical (paleogeographical and paleoecological) events seem to have played a minor role. However, the isolation of ancient earwig stocks on Italian mountains led to the origin of a relatively large number of endemics, which makes the Italian earwig fauna one of the richest in Europe. [ABSTRACT FROM AUTHOR]

Data on reproduction of the earwig Forficula vicaria Semenov (Dermaptera, Forficulidae) in Primorskii Territory of Russia are presented. The total period of reproductive activity lasts from 47 to 52 days. The earliest mating couples were recorded at the beginning of the last third of August, and the latest ones, in mid-October. The time spent by the male and female in the cage before mating was 28 days for the couple formed in late July, 17 days for that formed in early August, 5 days for that formed in mid-August, and less than a day for that formed in late August. The couples mated repeatedly 11–17 times over the entire period of observation. From 1 to 3 copulations were recorded daily, each lasting from 30 min to 10 h with intervals varying from 20 min to 9 h. Active feeding was observed for 1.5–4 h after mating. Females started laying eggs in late September; their fecundity ranged from 52 to 71 eggs per female, and from 4 to 33 eggs were laid daily between copulations. Mature eggs were present in the ovaries of dissected females until mid-October. Forficula vicaria is characterized by parental care; starting with mid-September, the adults make wintering shelters in which they hibernate protecting their eggs. [ABSTRACT FROM AUTHOR]

A growing number of studies show that anthropization can alter the behaviour, survival, physiology, cognition and reproduction of many animal species. However, its impact on parental care, a common behaviour where even subtle changes can have dramatic effects on the viability of future generations and thereby jeopardize population dynamics, remains surprisingly unclear. Here, we studied the effects of exposure to cadmium, a highly toxic chemical pollutant widely distributed in the trophic chain, on egg production and maternal egg care in the European earwig, Forficula auricularia. We fed 200 females with food containing cadmium at five different concentrations for several weeks, and then quantified the number of eggs produced, the expression of six forms of egg care and three forms of noncare behaviours, as well as maternal survival and egg development. In contrast to most results reported in other animal species, we found no evidence that ingestion of even substantial doses of cadmium affects egg production or maternal egg care in the form of grooming, antennation, displacement, gathering, defence or retrieval. Moreover, it neither affected maternal exploration, inactivity or self-grooming behaviours, nor egg development time, hatching rate or juvenile weight. Overall, these results reveal that egg care is resilient to environmental cadmium pollution in earwigs and suggest that females possess efficient and fast-acting physiological processes that help them reduce their sensitivity to heavy metal contamination. More generally, our findings may suggest that selection pressures associated with the necessity to express egg care has directly or indirectly selected for higher resistance/tolerance against certain chemical pollution, and thus that species with parental care could be more resilient in the face of increasing levels of anthropogenic pollution. • Egg care is an essential behaviour to ensure the viability of future generations. • Cadmium is highly toxic to organisms and affects numerous fitness-related traits. • We tested the effects of cadmium on egg care and reproduction in earwig females. • We found that egg care and female reproduction were independent of cadmium exposure. • The critical importance of egg care could explain the robustness of this behaviour. [ABSTRACT FROM AUTHOR]

Insects are the dominant group of animals on Earth. Despite this abundance, most of our knowledge about many aspects of their biology and development come from a unique model, the vinegar fly, Drosophila melanogaster. Nevertheless, in the last years, the advances in molecular tools and imaging techniques have allowed the emergence of new insect models, adding valuable information to decipher the morphogenetic bases behind the formation and evolution of the vast diversity of shapes, sizes, and patterns that characterize them. Earwigs belong to Dermaptera which is a small order clustered in the Polyneopteran group. They are hemimetabolous insects with a flattened body, characteristic abdominal pincers, and maternal care behavior. This last feature and their role in agroecosystems have been studied in cosmopolitan species such as Forficula auricularia and Euborellia annulipes; however, their reproduction and embryonic development have been poorly addressed in laboratory conditions. In response, here we describe the ring‐legged earwig Euborellia annulipes embryogenesis and life cycle from nymphal to adult stages, its reproduction, and essential morphological and behavioral characters. Additionally, using confocal and transmission electron microscopy we analyzed in detail the morphogenesis of its peculiar meroistic polytrophic ovary. Our aim is to provide an emerging model system to perform comparative studies on insect oogenesis, development, and morphological evolution. RESEARCH HIGHLIGHTS: Euborellia annulipes is proposed as an emerging model system to perform comparative studies on insect oogenesis, development, and morphological evolution.A temporal description of embryogenesis stages is reported in this polyneopteran hemimetabolous species.Cellular and morphological description of the dermapteran meroistic ovariole, with its single nurse cell nourishing the oocyte, is reported in E. annulipes. [ABSTRACT FROM AUTHOR]

Simple Summary: Earwigs (Dermaptera) have their highest diversity in the tropical areas of the southern hemisphere, whereas the temperate regions of the northern hemisphere have relatively few species. This pattern has been considered a reflection of their origin in Gondwana, the supercontinent that grouped most of the land masses in today's southern hemisphere, including Antarctica, South America, Africa and Madagascar. An analysis of the distributions of the major evolutionary lineages of earwigs supports the role of the Gondwanan breakup in determining the current patterns of their diversity, as well the influence of the Indian collision with the Eurasian plate. The dispersal into the Eurasian plate was largely constrained by the Himalayan orogenesis and the presence of colder temperatures. This climatic barrier was probably the most important factor that largely hampered the colonization of North America from South America. The Dermaptera are an insect order exhibiting their highest diversity in the tropical areas of the southern hemisphere. This pattern has been considered a reflection of a Gondwanan origin. However, this hypothesis has not been tested through analytical methods. In this paper, the world distribution of earwigs was analysed by using the 'Cladistic Analysis of Distributions and Endemism' (CADE), a method which groups areas of endemism on the basis of shared distributions and phylogenetic relationships among taxa. In addition, clustering techniques were applied to depict biotic relationships based on similarity indices. Results of CADE support the idea that Gondwanan fragmentation exerted a crucial role in shaping the current distribution of the main clades of earwigs. However, the relationships between India with South East Asia suggested a biotic interchange occurred after the Indian collision with the Eurasian plate. The overall scenario emerging from cluster analyses revealed a strong influence of dispersal events. Overall, the distribution of earwig major clades indicates that their biogeographical history was mainly characterized by vicariance events (led by the break-up of Gondwana) followed by large scale dispersal processes constrained by the Himalayan orogenesis and the presence of colder temperatures, which have largely hampered the colonization of the northern hemisphere. [ABSTRACT FROM AUTHOR]

The benefits of parental care are often seen as a cornerstone of family life evolution. However, recent studies show that sibling interactions can also confer substantial benefits to juveniles. Here, we tested a new hypothesis suggesting that the need for juveniles to access sibling interactions may encourage juveniles to remain in a family group, thereby consolidating the early stages of family life evolution when parental care is facultative. We set up juveniles of the European earwig, Forficula auricularia (a family-living insect in which maternal care is facultative and juveniles can forage for themselves and cooperate with siblings) either alone, with siblings, or with siblings and their mother, and then quantified effects on the development, morphology and four fitness-related behaviours of the resulting adults. We found that isolated juveniles reached adulthood more quickly and that these adults were overall larger but showed impaired aggregation behaviour when compared with juveniles raised together with siblings or with siblings and their mother. By contrast, sibling deprivation did not affect offspring survival, male forceps length (an ornament involved in reproductive success) and three other behaviours in adults (boldness, general activity and exploration). All these results were independent of adult sex, although females overall reached adulthood earlier and were larger than males. Altogether, our findings suggest that the potential benefits of sibling interactions measured in this study play a minor role in the maintenance of earwig family life. They also emphasize the need to study the evolutionary drivers of family life in species where all members can switch from family to solitary life, a scenario that probably prevailed in the early evolution of sociality. • Do the benefits of sibling interactions support the maintenance of family life? • We addressed this question by testing the effects of sibling deprivation in earwigs. • We found that it produces adults with impaired aggregation and faster development. • But it has no effect on survival and three other fitness-related behaviours. • This questions the role of sibling interactions in the emergence of family life. [ABSTRACT FROM AUTHOR]

The phenology of the earwig Forficula vicaria was studied in Primorskii Territory based on three-year observations in nature and in stationary cages. The species has a univoltine life cycle, with females and eggs overwintering in underground nests. The overwintered females protect their eggs and nymphs in spring, but later leave their nests and die in mid-June. The I instar nymphs appear since the middle third of May; the II instar nymphs, since the last third of May; the III instar nymphs, from the beginning of the middle third of June, and the IV instar nymphs, from the last third of June. The postembryonic development takes on average 65 days. Adult males appear in the beginning third of July, and adult females, in mid-July. Mating takes place from late August to mid-October, and oviposition, from late September to mid-October. The mean fecundity is about 60 eggs per female. Adults can be found on the soil surface and in natural shelters until the end of September. Males assist females in building the nests, but die after the first ground frost in October. [ABSTRACT FROM AUTHOR]

Sublethal exposure to pesticides can alter the survival and reproduction of a wide range of non-target organisms. However, it remains unclear whether this exposure can alter behaviours that are often essential for long-term population dynamics and maintenance, such as parental care. In this study, we tested the effect of pyriproxyfen exposure (an insect growth regulator) on maternal care in the European earwig, an insect that is both used in pest control in pip-fruit orchards and considered a pest in stone fruit orchards. We exposed 424 females at doses either 10 times lower, equivalent or 10 times higher than normal application rates in French orchards. As maternal care can change over the weeks of family life, we exposed the earwig mothers at five different days before and after egg hatching. We then measured the expression of ten forms of maternal care towards eggs and juveniles, six non-caring behaviours, eggs and juvenile development, metabolic reserves in mothers at egg hatching and females' production of a terminal clutch. First, our results revealed that the three tested doses of pyriproxyfen were non-lethal and confirmed that maternal care decreased throughout both pre- and post-hatching family life. However, we did not detect any effect of pyriproxyfen on maternal care and non-care behaviours, eggs and juvenile development, quantities of lipids, proteins and glycogen in mothers at egg hatching, and on the production of a future clutch. Overall, these findings suggest that the maximal doses of pyriproxyfen authorized in French orchards is likely to have limited effects on the short- and long-term maintenance of populations of the European earwig and raises fundamental questions about the nature of the link between juvenile hormone and parental care in insects. [ABSTRACT FROM AUTHOR]

One of the most investigated patterns in species diversity is the so-called latitudinal gradient, that is, a decrease in species richness from the equator to the poles. However, few studies investigated this pattern in insects at a global scale because of insufficient taxonomic and biogeographical information. Using estimates of earwig species richness at country level, their latitudinal diversity gradient was modelled globally and for the two hemispheres separately after correcting for differences in country areas. Separate analyses were also conducted for mainland and island countries. All analyses clearly indicated the existence of latitudinal gradients. The most plausible explanation for the observed pattern is the so-called tropical conservatism hypothesis, which postulates (1) a tropical origin of many extant clades, (2) a longer time for cladogenesis in tropical environments thanks to their environmental stability, and (3) a limited ability of historically tropical lineages to adapt to temperate climates. Earwigs probably evolved on Gondwana and secondarily colonized the Northern Hemisphere. This colonization was hampered by both geographical and climatic factors. The Himalayan orogenesis obstructed earwig dispersal into the Palearctic region. Additionally, earwig preferences for warm/hot and humid climates hampered the colonization of temperate regions. Pleistocene glaciation further contributed to reducing diversity at northern latitudes. [ABSTRACT FROM AUTHOR]

The first overview of the Laboulbeniomycetes of Ukraine is presented and includes 37 species belonging to 16 genera, 2 families (Laboulbeniaceae and Herpomycetaceae) and 2 orders (Laboulbeniales and Herpomycetales). Among them, Amorphomyces italicus, Botryandromyces heteroceri, Dimorphomyces myrmedoniae, Distolomyces forficulae, Herpomyces stylopygae, H. ectobiae, Hesperomyces virescens, Laboulbenia egens, L. flagellata, L. hyalopoda, L. luxurians, L. thaxteri, L. uncinata, L. vulgaris, Monoicomyces drusillae and M. labiatus are newly reported for Ukraine. All genera above, except for Laboulbenia, are reported for the first time from Ukraine. New records for Cantharomyces italicus, Laboulbenia cristata, L. pedicellata, L. rougetii, Misgomyces dyschirii and Rickia peyerimhoffii are also mentioned. [ABSTRACT FROM AUTHOR]

Orthopteroidea is an ecologically diverse group of incompletely transformed insects that includes several insect orders similar in development and structure. Many species from Dermaptera, Orthoptera, Mantodea, and Blattodea are sensitive to anthropogenic influences and are indicators of the external environment. Some species cause damage to agriculture and forestry; others are inhabitants of human dwellings and pests of food supplies. The aim of this study is to describe fauna of some orders of Orthopteroidea in the Republic of Mordovia, in the central part of European Russia. This study was conducted in April–October 1971, 1984, 1995, 1996, 1998, 2000, 2001, and 2004–2023. All possible habitats were studied using a variety of methods (entomological traps, pitfall traps, pan traps, etc.). An acoustic method of species identification was also used. For each observation, the coordinates of location, abundance, and dates were recorded. The dataset contains 4865 occurrences. In total, 16,644 specimens of Orthopteroidea were studied. The dataset contains 71 species including Dermaptera (4), Orthoptera (62), Mantodea (1), and Blattodea (4). Of these, 13 species are identified for the first time in the region; these mainly inhabit steppe areas. The presence of two Orthoptera species has not been confirmed yet during our studies; these species are noted in this paper according an old published paper. The biodiversity of Mordovia includes 73 species from four orders. The biology of numerous species, their seasonal dynamics, and some descriptions of biotopes and number of new species are described.

Many animals consume the feces of their conspecifics. This allo‐coprophagy can have benefits, such as access to nutrients and symbionts, but also risks for consumers, mainly due to direct contact with pathogens that develop on feces. In the European earwig Forficula auricularia, mothers and juveniles live in nests lined with their feces. This surprising habit allows juveniles to consume the feces of their siblings during family life and provides them with nutritional benefits when mothers provide low care. However, it was unclear whether earwig mothers also practice allo‐coprophagy, and whether this behavior is motivated by their nutritional needs. Here, we set up four types of experimental families in which we manipulated the nutritional needs of mothers and/or juveniles and measured the effects on the production of feces by the juveniles, and the consumption of these feces by the mothers. Our results first show that fed juveniles produced more feces pellet in presence of fed compared to food‐deprived mothers. We also found that, overall, about 50% of the mothers consumed juveniles feces. This consumption was both more likely and larger when the feces were produced by fed compared to food‐deprived juveniles, while the proportion of feces pellets eaten was larger in food‐deprived compared to fed mothers. Overall, our results reveal that allo‐coprophagy involves every family member and suggest that it can have both nutritional and non‐nutritional benefits for earwig mothers. Allo‐coprophagy could thus favor the maintenance of mothers in the nest and, more generally, promote the early evolution of family life. [ABSTRACT FROM AUTHOR]

The phylogenetic position and inner relationships of Dermaptera remain unresolved despite the numerous efforts using morphological and molecular data. To facilitate the resolution of problems, this study sequenced the complete mitogenome of Apachyus feae de Bormans, 1894 (Apachyidae) and the nearly complete mitogenome of Diplatys flavicollis Shiraki, 1907 (Diplatyidae). The 19,029-bp long mitogenome of A. feae exhibited an extra trnV gene and two control regions in addition to the typical set of 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and two ribosomal RNA (rRNA) genes. The 12,950-bp long partially sequenced mitogenome of D. flavicollis was composed of 10 and a partial fragment of PCGs, 18 tRNA genes, two rRNA genes, and a control region. Comparative analysis of available earwig mitogenomes revealed variable mitogenomic structure and extensive gene rearrangements in Dermaptera. The preliminary phylogenetic analyses using Bayesian inference and maximum likelihood methods showed identical results, but the limited sampling and different types of molecular data lead to an apparent incongruence with previous phylogenetic studies. [ABSTRACT FROM AUTHOR]

Placed in the center of the Mediterranean biodiversity hotspot, Italy plays a central role for the study of Europe’s biogeography. In this paper, the influence of climatic, spatial, and historical factors on current patterns of variation in earwig species richness and composition is investigated. The Italian earwig fauna is mainly composed of species which are either widely distributed in Europe and the Palearctic region or that are endemic to the Alps and the Apennines. Variation in species richness does not follow any obvious geographical patterns, but a positive influence of precipitation on richness is consistent with earwig preferences for humid climates. European mainland territories did not contribute substantially to the current biodiversity of Italian earwigs, which explains the lack of a distinct peninsula effect, although a southward decrease in similarity with the central European fauna was observed. However, southern areas did not exert a pivotal role during Pleistocene glaciations in determining current patterns of species richness. Variation in species composition among Italian regions can be mostly explained by geographical proximity, while climatic differences and historical (paleogeographical and paleoecological) events seem to have played a minor role. However, the isolation of ancient earwig stocks on Italian mountains led to the origin of a relatively large number of endemics, which makes the Italian earwig fauna one of the richest in Europe.

The Dermaptera are an insect order exhibiting their highest diversity in the tropical areas of the southern hemisphere. This pattern has been considered a reflection of a Gondwanan origin. However, this hypothesis has not been tested through analytical methods. In this paper, the world distribution of earwigs was analysed by using the ‘Cladistic Analysis of Distributions and Endemism’ (CADE), a method which groups areas of endemism on the basis of shared distributions and phylogenetic relationships among taxa. In addition, clustering techniques were applied to depict biotic relationships based on similarity indices. Results of CADE support the idea that Gondwanan fragmentation exerted a crucial role in shaping the current distribution of the main clades of earwigs. However, the relationships between India with South East Asia suggested a biotic interchange occurred after the Indian collision with the Eurasian plate. The overall scenario emerging from cluster analyses revealed a strong influence of dispersal events. Overall, the distribution of earwig major clades indicates that their biogeographical history was mainly characterized by vicariance events (led by the break-up of Gondwana) followed by large scale dispersal processes constrained by the Himalayan orogenesis and the presence of colder temperatures, which have largely hampered the colonization of the northern hemisphere.

One of the most investigated patterns in species diversity is the so-called latitudinal gradient, that is, a decrease in species richness from the equator to the poles. However, few studies investigated this pattern in insects at a global scale because of insufficient taxonomic and biogeographical information. Using estimates of earwig species richness at country level, their latitudinal diversity gradient was modelled globally and for the two hemispheres separately after correcting for differences in country areas. Separate analyses were also conducted for mainland and island countries. All analyses clearly indicated the existence of latitudinal gradients. The most plausible explanation for the observed pattern is the so-called tropical conservatism hypothesis, which postulates (1) a tropical origin of many extant clades, (2) a longer time for cladogenesis in tropical environments thanks to their environmental stability, and (3) a limited ability of historically tropical lineages to adapt to temperate climates. Earwigs probably evolved on Gondwana and secondarily colonized the Northern Hemisphere. This colonization was hampered by both geographical and climatic factors. The Himalayan orogenesis obstructed earwig dispersal into the Palearctic region. Additionally, earwig preferences for warm/hot and humid climates hampered the colonization of temperate regions. Pleistocene glaciation further contributed to reducing diversity at northern latitudes.

Although pesticides are typically used to limit pest population, the diversity and nature of their unintentional effects on non-target organisms remain unclear. Better understanding these effects requires to carry out risk assessments on key physiological and behavioral processes specific to beneficial insects. In this study, we addressed this question by exposing mothers of the European earwig (a beneficial insect) to two sublethal doses of deltamethrin (a common pesticide in agriculture) during family life and measured the short- and long-term effects on a series of behavioral, physiological, and reproductive traits. Somewhat surprisingly, our results first revealed that high and low doses of deltamethrin enhanced mothers' future reproduction by augmenting their likelihood to produce a second clutch, shortening the number of days until its production, and increasing the resulting number of eggs and their hatching rate. Conversely, the high dose of deltamethrin was detrimental, as it limited maternal brood defence, and reduced food consumption and expression of self-grooming. Finally, other traits were independent of deltamethrin exposure, such as three proxies of family interactions (i.e., distance to the brood, occurrence, and duration of mother-offspring contacts), mothers' walking distance, and mother weight gain during family life. Our study overall demonstrates that sublethal exposure to a pesticide such as deltamethrin can have both positive and negative effects on non-target beneficial insects. It thus emphasizes that focusing on narrow parameters can lead to misleading conclusions about the unintended impacts of pesticides in treated agro-ecosystems and call for better considering this parameters diversity in integrated pest management programs. [ABSTRACT FROM AUTHOR]

We present herein the first phylogenetic analysis of the genus Chelidura and the taxonomic revision of the genus Chelidurella , stat. restit. , based on DNA sequences. The results confirm the generic status of Chelidurella Verhoeff, 1902 and Mesochelidura Verhoeff, 1902 , and they are removed from the synonymy with Chelidura and reinstated as valid genera. Many individual Chelidurella species are defined based on the combination of a few variable characters on the pygidium and forceps, and the systematics and phylogeny of this genus are unclear. The validity of most of the species is revisited here by molecular phylogenetic analyses, and individual morphological characters are evaluated for their relevance in the identification of all described species. We describe two new species to science, Chelidurella galvagnii Kirstová & Kočárek, sp. nov. from Austria, and C. pseudovignai Kočárek & Kirstová, sp. nov. from Italy and Austria; two species, C. guentheri Galvagni, 1994 and C. tatrica Chládek, 2017 are newly synonymized. Critical diagnostic characters are illustrated, and an identification key for males of Chelidurella is provided. [ABSTRACT FROM AUTHOR]

The microbes residing within the gut of an animal host often increase their own fitness by modifying their host's physiological, reproductive and behavioural functions. Whereas recent studies suggest that they may also shape host sociality and therefore have critical effects on animal social evolution, the impact of the gut microbiota on maternal care remains unexplored. This is surprising, as this behaviour is widespread among animals, often determines the fitness of both juveniles and parents, and is essential in the evolution of complex animal societies. Here, we tested whether life‐long alterations of the gut microbiota with rifampicin—a broad‐spectrum antibiotic—impair pre‐ and post‐hatching maternal care in the European earwig. Our results first confirm that rifampicin altered the mothers' gut microbial communities and indicate that the composition of the gut microbiota differs before and after egg care. Contrary to our predictions, however, the rifampicin‐induced alterations of the gut microbiota did not modify pre‐ or post‐hatching care. Independent of maternal care, rifampicin increased the females' faeces production and resulted in lighter eggs and juveniles. By contrast, rifampicin altered none of the other 21 physiological, reproductive and longevity traits measured over the 300 days of a female's lifetime. Overall, these findings reveal that altering the gut microbiota with a large spectrum antibiotic such as rifampicin does not necessarily affect host sociality. They also emphasize that not all animals have evolved a co‐dependence with their microbiota and call for caution when generalizing the central role of gut microbes in host biology. [ABSTRACT FROM AUTHOR]

BACKGROUND The European earwig, Forficula auricularia is an invasive insect pest found in many temperate regions of the world. Despite being well known predators, earwigs are considered pests in sweet cherry though this has never been empirically tested. Our aim was to quantify the relationship between damaged cherry fruit and earwig population size, cherry bunch size and earwig distribution in cherry tree canopies in the cherry varieties Ron's Seedling, Lewis, Sweet Georgia, and Lapin. RESULTS: Significant differences in earwig damage type and frequency were observed between varieties with earwig exclusion significantly reducing damage by 21% in Lapin and 34% in Ron's Seedling. Earwigs were strongly aggregated within cherry bunches, with greater numbers and damage observed in larger bunch sizes in all varieties except Ron's Seedling where stem damage was independent of bunch size. In Ron's Seedling, cherry stems were 40× more likely to be damaged than Lewis stems and Lewis fruit two times more likely to be damaged than Ron's Seedling fruit. Sweet Georgia fruit were 4.5 times and stems five times more likely to be damaged than in Lapin. No predictive relationship between cherry damage levels and earwig numbers either within the tree canopies or within monitoring traps could be determined. CONCLUSION: European earwigs may have a significant economic impact to sweet cherry production. The nature of this impact differs between cherry varieties and severity is strongly influenced by factors including bunch size. However, why damage differs between varieties remains unknown and warrants further investigation if the impact of earwigs to sweet cherry production is to be minimized. [ABSTRACT FROM AUTHOR]

Los cromosomas holocinéticos carecen de una constricción primaria y se encuentra mayormente en insectos, entre ellos el orden Dermaptera, comúnmente conocido como “tijeretas”. Los integrantes del género Doru son depredadores de plagas en cultivos de maíz, caña de azúcar y algodón, que se distribuyen ampliamente en Sudamérica. En Argentina se encuentran dos especies: D. lineare (Eschs.) y D. luteipes (Scudder). El material se recolectó en la provincia de Tucumán (Argentina). Para teñir los cromosomas se aplicaron técnicas citogenéticas clásicas, así como el método fluorescente DAPI. El análisis comparativo entre D. luteipes y D. lineare reveló que ambos taxones tienen fórmula haploide n = 10 (9A + XY) y 2n = 20. Además, se encontraron numerosas irregularidades meióticas y se observaron cromosomas holocinéticos sin constricción primaria que varían gradualmente en tamaño. Se presenta por primera vez información citogenética para D. luteipes, se realizan las primeras descripciones de los cariotipos para ambas especies y se discute el posible origen poliploide del género.

The subfamily Anataeliinae Burr, 1909 is restored in its original composition as one containing two genera: Anataelia Bolivar, 1899 and Challia Burr, 1904. Challiinae Steinmann, 1973, syn. n. is synonymized with Anataeliinae. Challia steinerisp. n. is described from Laos. "Anataelia" ramalhoi Sakai, 1996 described from Brazil is argued to belong to neither Anataelia nor Anataeliinae; it probably belongs to the subfamily Pygidicraninae. A detailed morphological redescription of A. canariensis Bolivar, 1899 is given. The history of the study, diagnoses, and possible apomorphies of the above-mentioned taxa are briefly discussed. The present wide distribution of Anataeliinae (the Canary Islands for Anataelia and East and South-East Asia for Challia) is apparently relict. [ABSTRACT FROM AUTHOR]

Technologies to fold structures into compact shapes are required in multiple engineering applications. Earwigs (Dermaptera) fold their fanlike hind wings in a unique, highly sophisticated manner, granting them the most compact wing storage among all insects. The structural and material composition, in-flight reinforcement mechanisms, and bistable property of earwig wings have been previously studied. However, the geometrical rules required to reproduce their complex crease patterns have remained uncertain. Here we show the method to design an earwig-inspired fan by considering the flat foldability in the origami model, as informed by X-ray microcomputed tomography imaging. As our dedicated designing software shows, the earwig fan can be customized into artificial deployable structures of different sizes and configurations for use in architecture, aerospace, mechanical engineering, and daily use items. Moreover, the proposed method is able to reconstruct the wing-folding mechanism of an ancient earwig relative, the 280-million-year-old Protelytron permianum. This allows us to propose evolutionary patterns that explain how extant earwigs acquired their wing-folding mechanism and to project hypothetical, extinct transitional forms. Our findings can be used as the basic design guidelines in biomimetic research for harnessing the excellent engineering properties of earwig wings, and demonstrate how a geometrical designing method can reveal morphofunctional evolutionary constraints and predict plausible biological disparity in deep time. [ABSTRACT FROM AUTHOR]

In order to determine the composition, abundance and diversity of soil dwelling insects in an agricultural field of corn production (5 ha), in the district of La Molina (Lima, Peru), 12 pit falls were installed, which were evaluated weekly for approximately 4 months (March-June). Collective samples were processed by separating individuals by morphotypes, recording the quantity and date of the collection. Finally, the specimens were identified in the Laboratory of the Klaus Raven Büller Entomology Museum with the help of identification keys and, in some cases, by comparison with museum specimens. Individuals of the orders Orthoptera (Families Acrididae and Gryllidae); Dermaptera (Family Anisolabididae); Coleoptera (Families Carabidae, Staphylinidae, Tenebrionidae, Scarabaeidae and Elateridae); and Hymenoptera (Family Formicidae) were identified. Order Hymenoptera was the most abundant with genus Linepithema sp. (Family Formicidae). Order Coleoptera registered the highest number of identified morphospecies, among which Blennidus peruvianus was the most predominant. The analysis of diversity gave a high value of Simpson's dominance index (0.91 ± 0.006), whereas the Shannon index value was intermediate (2.67 ± 0.05). The Chao1 and ACE estimators indicated that the specific richness observed in the field was very close to the estimated, giving a sampling effort between 81.9 and 84.7%. [ABSTRACT FROM AUTHOR]

• Gregarines are among the most frequently found parasites in the gut of arthropods. • Gregarines have long been known for the costs they incur to their hosts. • We showed that gregarine infection is not costly in the European earwig. • Moreover, it comes with apparent benefits in terms of survival. • We discuss why gregarines could be involved in a mutualistic relationship. Studying the costs and benefits of host-parasite interactions is of central importance to shed light on the evolutionary drivers of host life history traits. Although gregarines (Apicomplexa: Sporozoa) are one of the most frequent parasites in the gut of invertebrates, the diversity of its potential impacts on a host remains poorly explored. In this study, we addressed this gap in knowledge by investigating the prevalence of natural infections by the gregarine Gregarina ovata and testing how these infections shape a large set of morphological, behavioural and physiological traits in the European earwig Forficula auricularia. Our results first show that G. ovata was present in 76.8% of 573 field-sampled earwigs, and that its prevalence was both higher in males compared with females and increased between July and September. The load of G. ovata in the infected individuals was higher in males than females, but this sex difference vanished during the season. Our experiments then surprisingly revealed apparent benefits of G. ovata infections. Food-deprived hosts survived longer when they exhibited high compared with low gregarine loads. Moreover, the presence of gregarines was associated with a reduced phenoloxidase activity, indicating a lower immune resistance or a higher immune tolerance of the infected hosts. By contrast, we found no effect of G. ovata presence and number on earwigs' development (eye distance, forceps length), activity, food consumption or resistance against a fungal pathogen. Overall, our findings suggest that G. ovata could be involved in a mutualistic relationship with the European earwig. Given the ubiquitous presence of gregarines among invertebrates, our data also suggest that this common member of insect gut flora could have a broad and positive role in the life history of many host species. [ABSTRACT FROM AUTHOR]

In many animal species, mothers eat some of their own eggs. While this filial egg cannibalism can have profound impacts on both parental and offspring fitness, it remains unclear whether this behaviour is a simple by-product of a generally low maternal investment in egg care and whether it is determined before or after egg production. Here, we addressed these questions in the European earwig, Forficula auricularia, an insect in which females vary in their level of investment in egg care and in their expression of egg cannibalism. Using a cross-fostering experiment, we investigated the benefits of egg cannibalism for mothers, the potential association between egg cannibalism and egg care, and whether egg cannibalism is a maternal strategy that is determined before or after egg laying. Our results first revealed that egg cannibalism provided direct benefits to mothers, as the females that consumed some of their eggs increased their investment in future reproduction. We then showed that egg cannibalism was independent of the level of maternal investment in two important forms of egg care (egg defence and the time taken to return after a simulated predator attack). Overall, this suggests that access to egg cannibalism may select for mothers to remain with their eggs, independent of the potential benefits of care for the eggs. Finally, we demonstrated that the number of eggs received, but not the number of eggs produced by foster mothers, determined the level of egg cannibalism. This highlights that egg cannibalism is determined after egg laying and is not the outcome of anticipatory maternal effects. Overall, these findings provide novel insights into our understanding of the early evolution of parental care, as they suggest that the direct benefits of filial egg cannibalism for mothers could have promoted egg attendance from an ancestral egg abandonment state. • Filial egg cannibalism has profound impacts on both parental and offspring fitness. • European earwig mothers benefited directly from eating some of their eggs. • Egg cannibalism was independent of the level of maternal investment. • It is determined after egg laying and is not an anticipatory maternal effect. • It is not a simple by-product of a low maternal investment in care. [ABSTRACT FROM AUTHOR]

Neuropeptides are among the structurally most diverse signaling molecules and participate in intercellular information transfer from neurotransmission to intrinsic or extrinsic neuromodulation. Many of the peptidergic systems have a very ancient origin that can be traced back to the early evolution of the Metazoa. In recent years, new insights into the evolution of these peptidergic systems resulted from the increasing availability of genome and transcriptome data which facilitated the investigation of the complete neuropeptide precursor sequences. Here we used a comprehensive transcriptome dataset of about 200 species from the 1KITE initiative to study the evolution of single-copy neuropeptide precursors in Polyneoptera. This group comprises well-known orders such as cockroaches, termites, locusts, and stick insects. Due to their phylogenetic position within the insects and the large number of old lineages, these insects are ideal candidates for studying the evolution of insect neuropeptides and their precursors. Our analyses include the orthologs of 21 single-copy neuropeptide precursors, namely ACP, allatotropin, AST-CC, AST-CCC, CCAP, CCHamide-1 and 2, CNMamide, corazonin, CRF-DH, CT-DH, elevenin, HanSolin, NPF-1 and 2, MS, proctolin, RFLamide, SIFamide, sNPF, and trissin. Based on the sequences obtained, the degree of sequence conservation between and within the different polyneopteran lineages is discussed. Furthermore, the data are used to postulate the individual neuropeptide sequences that were present at the time of the insect emergence more than 400 million years ago. The data confirm that the extent of sequence conservation across Polyneoptera is remarkably different between the different neuropeptides. Furthermore, the average evolutionary distance for the single-copy neuropeptides differs significantly between the polyneopteran orders. Nonetheless, the single-copy neuropeptide precursors of the Polyneoptera show a relatively high degree of sequence conservation. Basic features of these precursors in this very heterogeneous insect group are explained here in detail for the first time. [ABSTRACT FROM AUTHOR]

The recent development of human societies has led to major, rapid, and often inexorable changes in the environment of most animal species. Over the last decades, a growing number of studies formulated predictions on the modalities of animal adaptation to novel or changing environments, questioning how and at what speed animals should adapt to such changes, discussing the levels of risks imposed by changes in the mean and/or variance of temperatures on animal performance, and exploring the underlying roles of phenotypic plasticity and genetic inheritance. These fundamental predictions, however, remain poorly tested using field data. Here, we tested these predictions using a unique continental‐scale data set in the European earwig Forficula auricularia L., a univoltine insect introduced in North America one century ago. We conducted a common garden experiment, in which we measured 13 life‐history traits in 4,158 field‐sampled earwigs originating from 19 populations across North America. Our results first demonstrate that 10 of the 13 measured life‐history traits are associated with two sets of variations in seasonal temperatures, that is, winter–summer and autumn–spring. We found, however, no association with the overall mean monthly temperatures of the invaded locations. Furthermore, our use of a common garden setup reveals that the observed patterns of variation in earwigs' life‐history traits are not mere plastic responses to their current environment, but are either due to their genetic background and/or to the environmental conditions they experienced during early life development. Overall, these findings provide continent‐scale support to the claims that adaptation to thermal changes can occur quickly (in less than 100 generations), even in insects with long life cycles, and emphasize the importance of variation in seasonal temperature over mean population temperatures in climate adaptation. [ABSTRACT FROM AUTHOR]

Earwigs (Dermaptera) use different strategies to increase their reproductive success. Most species lay eggs; however, viviparity of the matrotrophic type has been reported in two groups: Hemimeridae and Arixeniidae. In Arixeniidae, offspring develop in two separate places: inside an ovary (the intraovarian phase) and within a uterus (the intrauterine phase). Both morphological and physiological aspects of viviparity in Arixeniidae have begun to be unraveled only recently. Here, we characterize how the first instar larvae of Arixenia esau, developing inside the mother's reproductive system, manage respiration and gas exchange. Using modern light and electron microscopy techniques as well as immunological approach, we provide a detailed account of the maternal and larval tissue interactions during the intrauterine development. We demonstrate that respiration in the Arixenia first instar larvae relies on the extensive tracheal system of the mother as well as a respiratory pigment (hemocyanin) present within the body cavity of the larvae. Our results indicate that the larval fat body tissue is the likely place of the hemocyanin synthesis. Our study shows that characteristic cone-shaped lobes of the outgrowths located on the larval abdomen are a part of a placenta-like organ and mediate the gas exchange between the maternal and larval organisms. Based on the obtained results, we propose that Arixenia esau evolved a unique biphasic system supporting respiration of the first instar larvae during their development inside the mother's reproductive tract. [ABSTRACT FROM AUTHOR]

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the main pest of brassica crops worldwide. The ringlegged earwig, Euborellia annulipes (Lucas) (Dermaptera: Anisolabididae), has been reported as a potential predator of lepidopteran larvae, including this pest, and may therefore be used for biological control. Knowledge about predator–prey interactions is important to establish pest management strategies. Therefore, the objective of this work was to evaluate the influence of the developmental stage (larva and pupa) and density of P. xylostella on the preference and functional response of E. annulipes adult females. We used choice and no‐choice tests to evaluate the foraging behavior and preference of E. annulipes on DBM life stages and varied prey density to assess the type of functional response of the ringlegged earwig. Larvae were preferred over pupae, and the predator's functional response was type II for both prey stages. Our results report the potential of E. annulipes as a biocontrol agent of P. xylostella. Understanding their interactions may help in decision‐making and optimization of integrated management strategies. [ABSTRACT FROM AUTHOR]

The rejection of foreign individuals is considered a central parameter in the evolution of social life. Within family units, parents are typically thought to reject foreign offspring to ensure that their investment into care is directed towards their own descendants. Whereas selection for such kin bias is expected to be high when parental care is extended and involves numerous and energetically costly behaviors, it can be reduced when the acceptance of foreigners provide subsequent benefits to [ABSTRACT FROM AUTHOR]

Dispersion patterns within a group can reveal important aspects about social interactions and sexual selection within a species. We examined the distribution patterns of the maritime earwig (Anisolabis maritima), an insect well suited for studies of aggression, sociality, and sexual selection since both sexes live in close proximity and possess weaponry in the form of sexually dimorphic pincers. To examine intra‐ and intersexual interactions within small groups, we conducted trials with three earwigs with limited access to shelters. In single‐sex trios, we found that both males and females exhibited strong size‐based intrasexual aggression, as larger individuals were less likely to be excluded from shelters; however, males were more likely to cohabitate than females. In mixed‐sex trios, we found that both males and females preferred smaller opposite‐sex partners, and cohabitation patterns indicate that both sex‐ and size‐based differences in aggression can influence overall spatial distribution. We also examined larger single‐sex and mixed‐sex groups of 18 earwigs to determine whether they had random, uniform, or clumped distributions. Similar to previous field observations, males tended to form aggregations, whereas females were distributed uniformly, a pattern indicative of territoriality. Mixed‐sex groups, on the other hand, were uniform during nocturnal periods of high activity but then become clumped after settling into more stable daytime positions. Overall, our results suggest that females have high levels of aggression regardless of the social context, whereas males alter their aggressive behavior in the presence of females. [ABSTRACT FROM AUTHOR]

In the last 40 years, the number of species in the orthopteroid orders has increased by ~10% from that known in 1979. The largest order, the Orthoptera, has increased from 205 to 235 species known in Canada. The number of Blattodea has increased from 14 to 18 species, while Dermaptera has increased from 5 to 6 species. The number of species of Mantodea (3) and Phasmida (1) known in Canada have remained unchanged. Most new species records reported in Canada since 1979 have resulted from new collections along the periphery of the range of more widespread species. Some species reported since 1979 are recent introductions to Canada, including species restricted to homes or other heated buildings. The taxonomy of these orders has also changed, with only the Dermaptera having maintained its order definition since the 1979 treatment. Additional orthopteroid species are likely to occur in Canada, particularly in the orders Orthoptera and Blattodea. DNA barcodes are available for more than 60% of the species known to occur in Canada. [ABSTRACT FROM AUTHOR]

The ecology of earwigs in natural forest ecosystems is poorly understood. We used sweeping to determine the population densities of adult earwigs, by sex and species, on ten tree species in a temperate floodplain forest in southern Moravia (Czech Republic). We also determined the relationships between the properties of tree species and earwig density and diet as indicated by digestive tract contents. The densities and diet composition of earwigs differed between the three detected earwig species [Apterygida media (Hagenbach, 1822), Chelidurella acanthopygia (Genè, 1832) and Forficula auricularia Linnaeus, 1758] and among tree species. Earwig densities were related to lichen coverage and fungal coverage on the trees. The diet of earwigs was associated with specific leaf area, herbivore damage to the leaves, and light exposure of the trees. A. media was the most abundant of the three earwig species. Although the contents of its digestive tract changed depending on available food resources, A. media appeared to preferentially consume soft-bodied insect herbivores and fungi associated with wounds caused by herbivores rather than plant material. Therefore, this species has the potential to help reduce the population densities of soft-bodied pests of forest trees. [ABSTRACT FROM AUTHOR]

Earwig wings are highly foldable structures that lack internal muscles. The behaviour and shape changes of the wings during flight are yet unknown. We assume that they meet a great structural challenge to control the occurring deformations and prevent the wing from collapsing. At the folding structures especially, the wing could easily yield to the pressure. Detailed microscopy studies reveal adaptions in the structure and material which are not relevant for folding purposes. The wing is parted into two structurally different areas with, for example, a different trend or stiffness of the wing veins. The storage of stiff or more flexible material shows critical areas which undergo great changes or stress during flight. We verified this with high-speed video recordings. These reveal the extent of the occurring deformations and their locations, and support our assumptions. The video recordings reveal a dynamical change of a concave flexion line. In the static unfolded state, this flexion line blocks a folding line, so that the wing stays unfolded. However, during flight it extends and blocks a second critical folding line and prevents the wing from collapsing. With these results, more insight in passive wing control, especially within high foldable structures, is gained.