Forficula Auricularia Research Articles

Heat waves during egg development alter maternal care and offspring quality in the European earwig

Heat waves during egg development alter maternal care and offspring quality in the European earwig

Intraguild Predation or Spatial Separation? The efficacy and Interactions of Two Natural Enemy Species for the Biological Control of Pear Psyllid (Cacopsylla pyri)

AbstractPear psyllid (Cacopsylla pyri) is a persistent pest to the pear industry; with an estimated cost of £5 million per annum in the UK alone. This phloem feeding insect is resistant to a large proportion of approved pesticides, necessitating the use of alternative control strategies. Many pear growers practice integrated pest management (IPM) of pear psyllid, focusing on maximizing natural enemy populations, whilst minimizing the use of agrochemical sprays. The anthocorid Anthocoris nemoralis and the European earwig Forficula auricularia are particularly effective at controlling pear psyllid populations during the summer months. Despite the effectiveness of both natural enemies, there is a lack of understanding on whether both species should be promoted together or separately, due to the risk of intraguild predation (IGP) or interference competition. Furthermore, abiotic factors including temperature may influence both behaviors, altering activity level and niche overlap. Although IGP and interference competition have been documented between multiple species of natural enemies neither have been studied between these two specific predators. Using microcosm experiments, olfactometer assays and survival analyses this study demonstrated whether A. nemoralis and F. auricularia can be used in synchrony to control pear psyllid. Results indicated that IGP is present; F. auricularia will consume A. nemoralis when predators are not spatially separate and in absence of psyllid prey. There was no evidence for interference competition, although both predators consumed more prey at higher temperatures. This confirms that pear growers can encourage both predators for the control of pear psyllid without losing predation efficacy.

The European earwig: a model species for studying the (early) evolution of social life

The European earwig: a model species for studying the (early) evolution of social life

New perspective on the role of Doru luteipes as a predator of the fall armyworm: Non‐consumptive effects, predatory preference and functional response

AbstractIn Brazil, the common earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae) is considered an important biocontrol agent for the maize crop, consuming the fall armyworm Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) eggs and caterpillars from 1st to the 3rd instar. Despite this, several aspects of the interaction between these species have not yet been studied. We aim to evaluate the non‐consumptive effects of earwigs on the oviposition of moths, the earwig's predatory preference between eggs and neonates and its functional response to S. frugiperda eggs. In no‐choice tests between plants with or without the presence of the predator, S. frugiperda moths deposited a smaller number of eggs on plants with risk of predation. In choice‐based tests, earwigs initially attacked newborn caterpillars, but preferred to feed on eggs. Males and females fed more on eggs with increasing supply density and consumption was adjusted to the type II functional response curve. D. luteipes males were more efficient predators than females when exposed to higher egg densities. These findings clarify aspects of the predatory role of D. luteipes on S. frugiperda that had not yet been addressed and suggest that the earwig has potential for impacting the colonization and population growth of S. frugiperda in maize crops, if conditions are favourable to its early arrival.

Limited effects of a glyphosate-based herbicide on the behaviour and immunity of males from six populations of the European earwig.

The use of herbicides on crops often results in unintentional, low-dose exposure of non-target organisms, such as insects. While these exposures are increasingly known to alter the survival and physiology of insects, it remains unclear whether these effects can vary between populations and modify other fitness-related traits, such as behaviour and immunity. Here, we addressed these questions by testing the effects of sublethal exposure to a glyphosate-based herbicide (GBH) on the behaviour and immunity of European earwig males from six natural populations. We exposed each male to a dose of a common GBH (Roundup©) that was either recommended for crops, five times lower than that recommended for crops, or to a control solution. Twenty-four hours later, we measured the activity, boldness, and aggregation of each male. We then exposed them to an entomopathogenic fungus, monitored their survival for 6weeks, and measured the immune response of the survivors. We found a condition-dependent effect of GBH exposure on male activity. Exposure to low doses induced a positive association between activity and weight, which was not observed in the high-dose and control groups. However, GBH had no effect on any of the other measured traits. All these results were consistent across the six populations tested, although we did find population-specific differences in almost all measurements on males. Further research is now needed to better understand the dose-response to GBH on male activity and its biological impact, as well as to evaluate the effectiveness of detoxification processes in this species. Overall, these results emphasise the importance of investigating the effects of herbicides on insects to expand our general understanding of the use and potential risks of plant protection products in integrated pest management programs.

Relationship between weapon size and six key behavioural and physiological traits in males of the European earwig

Relationship between weapon size and six key behavioural and physiological traits in males of the European earwig

A shift towards softer pest management differently benefits earwig and spider communities in a multiyear experiment in apple orchards.

Environmentally-friendly crop protection practices are needed to enhance the sustainability of current agricultural systems. This is crucial in orchards which are extensively treated to impair various pests, at the expense of natural enemies. However, the effect of a shift towards softer pest management on the beneficial arthropod community is poorly documented. Earwigs (Dermaptera: Forficulidae) and spiders (Araneae) are relevant groups to assess such effects because they are highly sensitive to agricultural practices. They were monitored for 6 and 4 years, respectively, in apple orchards under three pest management regimes: Organic, Low-input and Conventional, with pest management being switched during the survey from a broad-spectrum insecticide schedule to mating disruption in the latter one, and more selective compounds in all orchards. The survey displayed that earwig abundance (mainly Forficula auricularia) that was initially very low in the Conventional orchard (annual mean 0.5-1.7 earwigs per shelter in the 2010-2012 period) increased to the same level as that of Low-input and Organic orchards (over 10 earwigs per shelter) in the same year that changes in pest management occurred. The epigeal and arboreal spider communities were not responsive, and no recovering was observed 4 years after change in practices. Predatory arthropod communities are differently affected over time by changes in pest management, most probably due to their biology (dispersion, reproduction rate, susceptibility to pesticides etc.). This outlines the importance of documenting the time required to recover after perturbations and build a natural enemy community to enhance pest control in a win-win perspective. © 2024 Society of Chemical Industry.

The unreliable signal: No correlation between forceps length and male quality in European earwigs

The unreliable signal: No correlation between forceps length and male quality in European earwigs

Orthopteroids on three Species of Cistaceae in the Region of Tlemcen (Algeria)

The region of Tlemcen is located in the northwestern part of Algeria. It is characterized by the Mediterranean climate. It moves away from the coast about 60 km.Cistus salvifolius or Cistus with sage leaves is a thermophilic shrub characterizing the Mediterranean region. It is a moderately fragrant plant that can reach 100 cm in height. Cistus ladaniferus or Cistus gum is a woody pyrophyte shrub with glutinous leaves, used in medicine up to 1.5 m in height. These two cists are found in the mountains of Tlemcen. On the other hand, Cistus monspeliensis is a shrub with very vigorous vegetation known for its medicinal virtues and is present in the Nedroma zone.We propose to study the Orthopteroid fauna associated with these three Cistaceae. It includes 3 orders namely Orthoptera, Mantoptera and Dermaptera. The order of Orthoptera is divided into 02 sub-orders: that of Caelifera includes 03 families: those of Pamphagidae, Pyrgomorphidae and Acrididae. The second suborder, which of the Ensifers, comprises 2 families: those of the Gryllidae and the Tettigoniidae. The order Mantoptera includes the family Mantidae. The order Dermaptera has only one family, that of Forficulidae. Of the 3 Cistaceae, 25 species of Orthopteroids have been inventoried. Cistus ladaniferus has 16 species; C.salvifolius and C. monspeliensis have 15 species respectively. Orthoptera are the most numerous. We count 13 species on the sage-leaved cistus.Two species of Mantidae are found on the rockrose. Mantis religiosa is found in the different stations of Cistaceae. Sphodromantis linicola is found on Cistus ladaniferus. Forficula auricularia (Dermaptera) is present on all three Cists. Six species of Orthopteroids seem common to the 3 plants considered.

Arthropods in the spotlight – identifying predators of vineyard pest insects with infrared photography

AbstractGrape berry moths, particularly Lobesia botrana Denis & Schiffermüller (Lepidoptera: Tortricidae), and vinegar flies, such as Drosophila melanogaster Meigen and Drosophila suzukii Matsumura (Diptera: Drosophilidae), are important vineyard pests, causing severe quality loss of grapes. Several arthropod taxa may be involved in the natural control of these pests. However, the role of arthropod predators in the natural control of vineyard pests remains unclear. We investigated 32 vineyards in the Palatinate region, southwest Germany, under organic and conventional management, which in both cases received either full or reduced fungicide applications (2 × 2 design). Predation of L. botrana eggs and pupae and D. melanogaster pupae on sentinel cards exposed in the vineyards was observed with infrared cameras. In total, nine predator taxa could be identified. The most dominant predator was the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), with 90% of all predation events. We conclude that F. auricularia is likely a key predator of vineyard pests, and that special attention should be paid to maintain it at high population densities.

With or without you: gut microbiota does not predict aggregation behavior in European earwig females

Abstract 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.

Arthropods as Vectors of Grapevine Trunk Disease Pathogens: Quantification of Phaeomoniella chlamydospora on Arthropods and Mycobiome Analysis of Earwig Exoskeletons.

Viticulture worldwide is challenged by grapevine trunk diseases (GTDs). Involvement of arthropods in the dissemination process of GTD pathogens, notably esca pathogens, is indicated after detection of associated pathogens on arthropod exoskeletons, and demonstration of transmission under artificial conditions. The present study is the first to quantify spore loads via qPCR of the esca-relevant pathogen Phaeomoniella chlamydospora on arthropods collected in German vineyards, i.e., European earwigs (Forficula auricularia), ants (Formicidae), and two species of jumping spiders (Marpissa muscosa and Synageles venator). Quantification of spore loads showed acquisition on exoskeletons, but most arthropods carried only low amounts. The mycobiome on earwig exoskeletons was described for the first time to reveal involvement of earwigs in the dispersal of GTDs in general. Metabarcoding data support the potential risk of earwigs as vectors for predominantly Pa. chlamydospora and possibly Eutypa lata (causative agent of Eutypa dieback), as respective operational taxonomical unit (OTU) assigned genera had relative abundances of 6.6% and 2.8% in total reads, even though with great variation between samples. Seven further GTD-related genera were present at a very low level. As various factors influence the successful transmission of GTD pathogens, we hypothesize that arthropods might irregularly act as direct vectors. Our results highlight the importance of minimizing and protecting pruning wounds in the field.

Dermaptera Community Structure on Oil Palm Ecosystem in Dharmasraya District, Indonesia

The oil palm ecosystem is one of the suitable habitats for the order Dermaptera. Several physical factors, especially humidity in the oil palm ecosystem, support these insects' existence. In the oil palm ecosystem, Dermaptera has several functions, including as a predator of oil palm pests, but on the other hand, these insects also prey on Elaeidobius kamerunicus Faust, the primary pollinator of oil palm plants. For that reason, research was conducted to study the structure of the Dermaptera community in the ecosystem of oil palm plantations in the Sitiung sub-district. This research was a survey conducted at three locations- Sitiung, Gunung Medan, and Sungai Duo Villages—the collection of insect samples by hand collection. Identification of insect samples was carried out at the species level according to Burr (1910) and Borror et al. (1996). In this study, 214 individuals of the order Dermaptera were found to consist of three species: Cheslisoches mario, Forficula auricularia, and Vostox brunneipennis. C. mario was the dominant Dermaptera species found with an Importance Value Index (IVI) was 1.27. Based on this research, it is known that the community structure of the order Dermaptera was simple because it has low diversity values.

New nephridiophagid genera (Fungi, Chytridiomycota) in a mallow beetle and an earwig.

Nephridiophagids are unicellular fungi (Chytridiomycota) that infect the Malpighian tubules of insects. Most species have been found in cockroach hosts and belong to the genus Nephridiophaga. Three additional genera have been described from beetles and an earwig. Here, we characterise morphologically and molecular phylogenetically the nephridiophagids of the European earwig Forficulaauricularia and the mallow beetle Podagricamalvae. Their morphology and life cycle stages resemble those of other nephridiophagids, but their rRNA gene sequences support the existence of two additional genera. Whereas the earwig nephridiophagid (Nephridiochytriumforficulaegen. nov. et sp. nov.) forms a sister lineage of the Nephridiophaga cluster, the mallow beetle nephridiophagid (Malpighivincopodagricaegen. nov. et sp. nov.) represents the earliest divergent lineage within the nephridiophagids, being sister to all other species. Our results corroborate the hypothesis that different insect groups harbour distinct nephridiophagid lineages.

Environmental complexity and predator density mediate a stable earwig-woolly apple aphid interaction

Regulation of insect pests by predators is an integral component of biological pest control. However, predator-prey interactions often reach a stable state leading to coexistence, which can be problematic for plant protection if the persisting herbivores exceed a damage threshold. Consequently, understanding the factors mediating this stability is crucial for successful biocontrol. Here, we investigated the predator-prey interaction of an important apple pest, the woolly apple aphid (WAA) (Eriosoma lanigerum Hausm.) (Hemiptera: Aphididae), and its predator, the omnivorous common earwig (Forficula auricularia L.) (Dermaptera: Forficulidae). To this end, we introduced increasing densities of earwigs in gauze-bagged branches harbouring defined amounts of WAA and recorded predation on individual WAA colonies for almost one month. We showed that the spatial complexity of the predation environment and the earwig density determined the predation efficiency on WAAs. Earwigs could eradicate WAAs regardless of density on short apple branches without lateral twigs (first trial). However, on longer, more complex branches (second trial), stable states of WAAs and earwigs were observed. Only the highest earwig density could completely consume WAA regardless of branch complexity. We introduce a conceptual model to describe the searching capability of earwigs, which determines their efficiency in locating prey. Our model predicts that searching capability is reduced by environmental complexity; this effect is alleviated by increased earwig density, as more predators possess a higher searching capability. Conclusively, our model explains why only the highest earwig density could completely consume WAA irrespective of complexity and illustrates how predator density and environmental complexity jointly influence predation. Thus environmental characteristics not inherent to our predator-prey interaction were a decisive factor for effective predation on gauze-bagged branches. Based on these results, reducing tree complexity by pruning or augmenting earwig populations in orchards can increase biocontrol of the WAA.

The Molecular Resistance Mechanisms of European Earwigs from Apple Orchards Subjected to Different Management Strategies.

To date, apple orchards are among the most treated crops in Europe with up to 35 chemical treatments per year. Combining control methods that reduce the number of pesticide treatments is essential for agriculture and more respectful of the environment, and the use of predatory insects such as earwigs may be valuable to achieve this goal. European earwigs, Forficula auricularia (Dermaptera: Forficulidae) are considered beneficial insects in apple orchards where they can feed on many pests like aphids. The aim of this study was to investigate the potential impact of orchards' insecticide treatments on resistance-associated molecular processes in natural populations of earwigs. Because very few molecular data are presently available on earwigs, our first goal was to identify earwig resistance-associated genes and potential mutations. Using earwigs from organic, integrated pest management or conventional orchards, we identified mutations in acetylcholinesterase 2, α1 and β2 nicotinic acetylcholine receptors. In addition, the expression level of these targets and of some essential detoxification genes were monitored using RT-qPCR. Unexpectedly, earwigs collected in organic orchards showed the highest expression for acetylcholinesterase 2. Four cytochromes P450, one esterase and one glutathione S-transferases were over-expressed in earwigs exposed to various management strategies in orchards. This first study on resistance-associated genes in Forficula auricularia paves the way for future experimental studies aimed at better understanding the potential competition between natural enemies in apple orchards in order to optimize the efficiency of biocontrol.

Turning a Pest into a Natural Enemy: Removing Earwigs from Stone Fruit and Releasing Them in Pome Fruit Enhances Pest Control.

The European earwig Forficula auricularia (L.) (Dermaptera: Forficulidae) is an omnivorous insect that is considered a minor pest of stone fruit and a key predator of pests in pome fruit orchards. In many pome fruit orchards, earwigs are absent or in low abundance due to broad-spectrum spray programs and the slow recolonization rate of earwigs. Orchards in transition to organic or "selective" conventional programs often struggle to achieve effective levels of biological control, and thus, may benefit from inoculating earwigs to expedite their re-establishment. In a two-year study, we evaluated the potential for mass trapping earwigs from stone fruit using rolled cardboard traps to reduce fruit damage and provide earwigs for augmentation in pome fruit. We also tested whether a single mass release or five releases (on alternating weeks) of the same total number of earwigs in apples and pears reduced pests relative to plots where no releases occurred. Mass trapping did not decrease earwig abundance or substantially reduce fruit damage in stone fruit orchards. However, trapping was an efficient method for providing earwigs for augmentation. Earwig abundances were only increased in orchards where earwigs were previously low or absent; however, multiple orchards with varying prior levels of earwigs exhibited reductions in key pests (woolly apple aphid and pear psylla). For some other pests evaluated, plots with mass releases of earwigs had a slight trend in overall lower pest density when compared with control plots. A strategy for moving earwigs out of stone fruit orchards and into pome fruit orchards could be an effective method for augmenting orchard predator populations.

Lethal and behavioural toxicity of differently aged insecticide residues on European earwigs (Forficula auricularia) in the laboratory and in the field

Pesticide residues are an important topic in many environmental studies, but little is known about the effects of pesticide residues of different ages on beneficial arthropods. Therefore, in this study the activity of residues of three different ages of several commonly used insecticides on the behaviour and mortality of European earwigs was evaluated in the laboratory and the effect of the insecticides was verified in the field. All residues of the biorational SpinTor® (spinosad), Radiant SC (spinetoram), and the conventional Steward® (indoxacarb) showed significantly faster mortality progression compared to the control in the laboratory. All the Steward® residues caused a significant wave of erratic behaviour as the earwigs went through a deep and relatively long moribund stage and resurrected. We verified the effects of SpinTor® and Steward® on changes in earwig abundance and their behaviour in the orchard. Earwigs abundance was significantly lower 16 days after application of biorational SpinTor® and conventional Steward® which had a significantly more pronounced and longer lasting effect. The earwig population stabilised by day 53 after the insecticide applications. Field applications of insecticides had no effect on earwig behaviour and sex ratio. Our results show that older residues have a negative effect on European earwigs equal to that of fresh residues, although their degradation should occur. It is interesting to note that biorational insecticides may not be safer than chemical insecticides.

Earwig Releases Provide Accumulative Biological Control of the Woolly Apple Aphid over the Years.

Nature-based solutions, such as biological control, can strongly contribute to reducing the use of plant protection products. In our study, we assessed the effect of augmentative releases of the European earwig (Forficula auricularia) to control the woolly apple aphid (Eriosoma lanigerum), a worldwide pest that causes serious damage to apple trees. The trials were carried out in two organic apple orchards located in Catalonia (NE Spain) from 2017 to 2020. Two treatments were compared: with vs. without earwig release. For the treatment, 30 earwigs per tree were released by means of a corrugated cardboard shelter. These releases were performed once per season and were repeated every year. We periodically assessed the length of the woolly apple aphid colonies, the number of colonies per tree, the percentage of aphids parasitized by Aphelinus mali, and the number of earwigs per shelter. Our results showed that earwig releases reduced the length of the colonies, but this effect was noticeable only for the second year onwards. Moreover, we found that those releases were compatible with A. mali. Overall, we demonstrated the positive impact of earwig releases on the woolly apple aphid control and the importance of considering time on augmentative biological control strategies.

Organic orchard floor management in peach: effects on arthropods and associated fruit injury in the Intermountain West.

Understanding orchard floor management is critical to organic tree-fruit production systems given its impact on weeds, soil fertility, tree health, and crop yield. Several viable options are available to producers for weed management and promotion of organic fertility, including use of turf and broadleaf alleyway covers and living and nonliving tree-row mulches. While these measures can be effective, little is known about how these strategies influence arthropod pests, which cause fruit injury. Here, we assessed 6 organic orchard floor management strategies for their impact on arthropod abundance and diversity in an organic peach production system in northern Utah from 2010 to 2014, using sweep netting and pitfall collections along with observed peach fruit damage. Generally, we found that alleyway and tree-row treatments had no impact on total arthropod diversity, species richness, or community diversity. However, earwig (Forficula auricularia) abundance was significantly impacted by alleyway and tree-row treatments that resulted in increased fruit injury. Trefoil alleyway treatments consistently increased earwig abundance across life-history stages, while mulch or Alyssum (straw) tree-row treatments harbored more earwigs and, as a result, increased earwig fruit injury. Since earwigs are especially prone to damaging young, developing fruits, it is imperative that more work is done to assess earwig abundances and life-history traits. Our results demonstrate that detrimental arthropods are sensitive to orchard floor management and can further inform integrated pest management approaches that complement sustainability goals.