Peter Duelli

• PhD
• Retired Researcher at Swiss Federal Institute for Forest, Snow and Landscape Research

Windthrow disturbance is an important driver of arthropod diversity in forests. In the past, studies have mainly focused on the first years after disturbance, and there are hardly any data on arthropod trajectories in windthrows and on salvage logging effects over decades. We sampled arthropods of different functional groups on 16 permanent plots f...

Most insects were dead when they were named by taxonomists, and predominantly morphological criteria have been used for more than two centuries. But in nature there are populations with individuals looking identical, that turn out to represent two or more different species, and others that look different but are single biological species. Coastal a...

While many studies on insect diversity report declines, others show stable, fluctuating or increasing trends. For a thorough understanding of insect trends and their effects on ecosystem functioning, it is important to simultaneously assess insect richness, abundance and biomass, and to report trends for multiple taxa. We analysed insect richness,...

Recent studies reporting widespread declines in arthropod biomass, abundance and species diversity raised wide concerns in research and conservation. However, repeated arthropod surveys over long periods are rare, even though they are key for assessing the causes of the decline and for developing measures to halt the losses. We repeatedly sampled a...

All nine presently known European species of the Apertochrysa prasina group (formerly the Pseudomallada prasinus group) are diagnosed. Separate keys for the identification of living and preserved specimens of each sex are presented. For males, the “furwing” trait (increased numbers of setae on costal crossveins) is often crucial for identification,...

Two of the most intriguing yet poorly understood taxa in the Chrysoperla carnea-group of green lacewings are the European species (alternatively, forms or ecotypes) known as Chrysoperla renoni and C. ankylopteryformis. These two rare taxa have been variously combined and separated by systematists over the years, but their taxonomic status remains c...

The mid-term impact of forest fires and windthrows on species compositions in the insect orders Neuroptera, Raphidioptera and Mecoptera was assessed in Swiss forests using standardized flight interception traps. For 50 species the abundances in intact control plots were compared to those in moderately or strongly disturbed forest stands. The catche...

Chrysopa walkeri MacLachlan, 1893 was found in 2002 and 1991 at two places in southern Switzerland (Canton Ticino: Meride and Castel San Pietro). Old museum specimens labelled as Chrysopa phyllochroma Wesmael, 1848 in the collection of Willy Eglin at the Natural History Museum in Basel turned out to be Chrysopa commata Kis & Ujhelyi, 1965 from the...

One goal was to get more data on the two presently known species of Sisyridae in Switzerland, Sisyra nigra (Retzius, 1783) (mainly still waters) and Sisyra terminalis Curtis, 1854 (mainly running waters). A second goal was to find additional species in Switzerland or in nearby regions. No further species was found within Switzerland. The most likel...

Tras más de un siglo de citas, dudas y conjeturas, se confirma la presencia de Sisyra nigra (Retzius, 1783) (Neuropterida, Neuroptera: Sisyridae) en la Península Ibérica, en base a nuevo material recolectado en el País Vasco. Se aportan datos sobre la morfología y genitalia de esta especie, y se incluye en la clave actualizada de los imagos de las...

Historically serving as repositories for morphologically-based taxonomic research, natural history collections are now increasingly being targeted in studies utilizing DNA data. The development of advanced molecular techniques has facilitated extraction of useable DNA from old specimens, including type material. Sequencing diagnostic molecular mark...

Larval morphology and substrate-borne vibrational courtship songs have been hypothesized to distinguish and isolate Chrysoperla 'nipponensis-B' from true 'Type A' Chrysoperla nipponensis (Okamoto), both of which occur sympatrically in eastern Asia. Here, we formally describe C. 'nipponensis-B' as Chrysoperla nigrocapitata sp.n., based on population...

Elevational gradients influence the distribution and abundance of species drastically and can lead to variation in community composition. Although coprophagous flies are of ecological and economic importance, their biodiversity and distribution are largely neglected. We studied the impact of steep elevational gradients and geography on the distribu...

Two collecting trips of two weeks each in 2012 and 2013 to the Greater and Lesser Caucasus region in the Republic of Georgia increased the species list of Neuroptera for Georgia from 32 to 63 species. Most of the 31 species new to Georgia were found in the family Chrysopidae, largely because several new species of that genus have been described in...

A new species of spongilla-fly (Neuropterida, Neuroptera, Sisyridae: Sisyra) is described from Western Africa (Guinea and Ivory Coast). This new Sisyra species differs from all other known African species both in its morphology and genitalia, and it seems to be most closely related to a species in Thailand.

Pristine forests are generally assumed to be biodiversity hotspots. Is management detrimental to biodiversity? In some of the last European remains of pristine beech forest in Transcarpathia (Western Ukraine) the influence of forest management on arthropod biodiversity was assessed. Pitfall and flight interception traps were used to compare species...

Atlantochrysa atlantica (McLachlan) is restricted to Madeira and the Canary Islands. To determine its origin, molecular and morphological methods were used to identify its closest relatives among 40 species of Chrysopidae in 23 genera. Phylogenetic analysis of nuclear DNA from PepCK, wg, and ATPase show monotypic Atlantochrysa in a clade that inclu...

Properties of single cells in the posterior lateral (PL) eyes of the jum ping spider Plexippus validus are described. Only one spectral class of cells was encountered and the spectra sensitivity was indistinguishable from that measured from the ERG , both peaking at ca. 535 nm. Angular sensi­ tivity (width of angular sensitivity function at the 50%...

Parallel (or convergent) evolution of vibrational mating songs between species confined to different continents has been found several times in the Chrysoperla carnea species‐group of cryptic (morphologically indistinguishable) green lacewings. Repeated parallel speciation resulting in taxa that differ in duetting songs but not in appearance or eco...

Green lacewings in the genus Chrysoperla are not always green. They can be yellow (autosomal recessive mutant); change from whitish-yellow to green as young adults; or temporarily turn yellowish, reddish, or brown during diapause. New findings on a yellow mutant in a natural population in southern California and on species-specific diapause colorat...

Windthrows in spruce forests provide a prime substrate for the population build‐up of bark beetles. Until now, no information has been available on the population development of associated parasitoids. The development of bark beetle and parasitoid populations was monitored on cleared and uncleared windthrow areas for 4 years, corresponding to the s...

Many species that depend on old trees and dead wood are suffering from habitat losses and intensive forest management. For the conspicuous cerambycid beetle Rosalia alpina, a relative sampling analysis combined with a distribution model showed a population decrease in Switzerland between 1900 and World War II. This negative trend can be ascribed to...

An unusual system of communication has evolved in green lacewings of the Chrysoperla carnea-group, triggering rapid proliferation of numerous cryptic species across all of the Northern Hemisphere and large portions of Africa. The system is based on sexually monomorphic, substrate-borne vibrational signals, produced by abdominal oscillation. These l...

Il numero di persone che vive in città è sempre maggiore. Le esigenze espresse dalla popolazione sugli spazi e gli ambienti verdi in città sembrano essere ottime premesse per una natura urbana diversificata e vitale, favorevole a molte specie di piante e animali presenti in città. Sono queste le conclusioni alle quali è giunto un vasto studio inter...

An unusual system of communication has evolved in green lacewings of the Chrysoperla carnea‐group, triggering rapid proliferation of numerous cryptic species across all of the Northern Hemisphere and large portions of Africa. The system is based on sexually monomorphic, substrate‐borne vibrational signals, produced by abdominal oscillation. These l...

Green lacewings of the Chrysoperla carnea species group use substrate-borne vibrational duetting songs rather than morphology or pheromones for species recognition. Because each of the many cryptic, reproductively isolated song species typically has an extensive geographic range, potentially interfertile biological species are broadly sympatric, an...

Les villes sont de plus en plus peuplées. Nos exigences vis-à-vis des espaces de détente et des paysages quotidiens coïncident étonnamment bien avec les conditions qui favorisent une nature urbaine diversifiée, habitat d’un grand nombre d’animaux et de plantes. Telle est la conclusion de l’étude en écologie et en sciences sociales à vaste échelle B...

In den Städten leben immer mehr Menschen. Unsere Ansprüche an Erholungsräume und Alltagslandschaften decken sich mit den Vor- aussetzungen für eine vielfältige Stadtnatur als Lebensraum für eine grosse Anzahl von Tieren und Pflanzen erstaunlich gut. Zu diesem Fazit kommt die breit angelegte ökologische und sozialwissenschaftliche Studie Biodive...

Across the Indian subcontinent, the agriculturally important Chrysoperla carnea species-group of Chrysopidae is represented by a single common species, Chrysoperla sillemi (Esben-Petersen, 1935). However, the cryptic species within the carnea group can be reliably distinguished from one another only by their substrate-borne vibrational duetting son...

It is often suggested that fire acts as an environmental filter that selects species and functional traits, and reduces trait variability within communities, affecting ecosystem function and underlying services. This may be particularly important in fire-sensitive ecosystems, such as the central European Alps, where fires are scarce. According to c...

Urban areas are a particular landscape matrix characterized by a fine-grained spatial arrangement of very diverse habitats (urban mosaic). We investigated arthropods to analyse biodiversity-habitat associations along five environmental gradients (age, impervious area, management, configuration, composition) in three Swiss cities (96 study sites). W...

Rapid biodiversity assessment (RBA) is proposed as an affordable indicator for monitoring local species richness of arthropods and sustainability of related ecosystem services. The indicator is based on strictly standardised sampling procedures and the identification of parataxonomic units (morphospecies) instead of species identification. The coll...

An important goal of ecological compensation areas (ECAs) is to increase biodiversity in adjacent intensively managed farmland and the agricultural landscape at large. We tested whether this goal can be achieved in the case of the agri-environmental restoration scheme implemented for Swiss grassland using five large arthropod taxa (bees, true bugs,...

According to the forest law, the conservation of biological diversity is an integral part of the multifunctional forestry in Switzerland. To date, biodiversity conservation has mainly been addressed by sustainable and partly nature-close forest practices and the conservation of rare biotopes and single threatened species. Some studies show that thi...

Agri-environment schemes play an increasingly important role for the conservation of rare plants in intensively managed agricultural landscapes. However, little is known about their effects on gene flow via pollen dispersal between populations of these species. In a 2-year experiment, we observed effective pollen dispersal from source populations o...

Background Agri-environment schemes play an increasingly important role for the conservation of rare plants in intensively managed agricultural landscapes. However, little is known about their effects on gene flow via pollen dispersal between populations of these species. Methodology/Principal Findings In a 2-year experiment, we observed effective...

The influence of natural disturbance on biodiversity is poorly known in the intensively cultivated landscape of Europe. As an example of insect disturbance we studied effects of gaps generated by outbreaks of the spruce bark beetle (Ips typographus) on biodiversity in the area of the National Park “Bavarian Forest” and compared them with openings (...

The influence of fire upon biodiversity has been investigated in many ecosystems under a wide range of environmental conditions. However, there is no information on how fire affects faunal biodiversity in deciduous forest ecosystems prone to winter fires, such as those on the southern slopes of the Alps. The main aim of this study was to analyse th...

The flight behaviour of Chrysopa cornea Steph. (Neuroptera: Chrysopidae) with regard to dispersal activity has been investigated in field experiments. There are three main types of flight activities. Shortly after emergence (in the first two nights) the adults perform adaptive dispersal flights which are straight downwind flights mostly at elevatio...

Abstract Systematic relationships among higher taxa within Chrysopidae, a large and agriculturally significant neuropteran family, are poorly understood. A molecular phylogenetic survey of Chrysopidae was performed with three nuclear genes, namely wingless (546 bp), phosphoenolpyruvate carboxykinase (483 bp), and sodium/potassium ATPase alpha subun...

We report the capture of two bee species new to Switzerland, Anthidium florentinum (Fabricius, 1775) and Stelis simillima (Morawitz, 1876), and of three rare species, Coelioxys echinata (Förster, 1853), Lithurgus chrysurus (Fonscolombe, 1834) and Lasioglossum discum (Smith, 185). All specimens were collected within the city limits of Lugano in the...

1. We studied the community and food-web structure of trap-nesting insects in restored meadows and at increasing distances within intensively managed grassland at 13 sites in Switzerland to test if declining species diversity correlates with declining interaction diversity and changes in food-web structure. 2. We analysed 49 quantitative food webs...

The success of the hotspot approach for biodiversity conservation depends on the spatial scale and the indicator species used. In this study, we investigated grasshopper species richness in Switzerland at a 1ha resolution including a total of 111 species. We compared the representativeness of common and of endangered grasshopper species for the ove...

1. Agri-environment schemes attempt to counteract the loss of biodiversity and associated ecosystem services such as pollination and natural pest control in agro-ecosystems. However, only a few studies have evaluated whether these attempts are successful. 2. We studied the effects of managing meadows according to the prescriptions of ecological co...

  We evaluated the preferred home ranges of three saproxylic beetle taxa along transects from the open field into the forest interior, and from the forest floor up to the canopy. By means of trap sets on metal scaffolds, vertical and horizontal strata were sampled across two types of forest edges: soft-edge ecotones with a gradual transition from t...

Landscape research needs to consider physical features and processes, as well as human prefer- ences. Anthropocentric value systems rule the world of perception and valuation of landscape quality, but different stakeholders have different motivations for planning, managing or protect- ing landscapes. The potential for conceptual or practical confli...

Crop and gut contents of field-collected adults of the European neuropteran species, Osmylus fulvicephalus (Scop.), were examined with glass slide preparations. Well chewed and partially digested insect fragments as well as pollen and fungal spores were found. Aphids, Heteroptera, Coleoptera, Diptera, and mites were noted. We assume that lepidopter...

The taxonomic status of green lacewings of the Chrysoperla carnea group from Africa and the Arabian Peninsula is investigated using comparative analyses of substrate‐borne vibrational songs, adult morphology, larval morphology and ecology. For the first time, the courtship song of C. zastrowi (Esben‐Petersen) is described and compared to the songs...

Changes in ecosystem functions following disturbances are of central concern in ecology and a challenge for ecologists is to understand the factors that affect the resilience of community structures and ecosystem functions. In many forest ecosystems, one such important natural disturbance is fire. The aim of this study was to understand the variati...

Effects of grassland management type and intensity on carabid species richness, number of individuals and species composition were studied in the Swiss Prealps. Carabids were censused in 2001 and 2002 in 21 mown and 20 grazed meadows by means of pitfall traps.Mean species richness was significantly higher in mown plots than in grazed plots and spec...

The forest fire area above Leuk (Canton Valais, Switzerland)has served since 2004 for several studies on ecological resilience. On the 300 ha patch that ranges from 800 to 2100 m a.s.l., several samples have been installed. Vegetation changes were monitored representatively on a grid of 125 m cell size. The vegetation of the intact forest vegetatio...

What makes virgin forests better forests? Biodiversity evaluation depends on the value systems of the stakeholders involved. Indicators for conservation value, ecosystem functions, wilderness, uniqueness, or species richness may not correlate, or even correlate negatively. Based on arthropod data from a comparative study in two types of virgin fore...

The species composition of arthropods was used for a pair-wise comparison of the biodiversity in virgin forests of the Ukrainian Carpathians and managed Swiss forests with similar tree species composition. In both countries, pure beech forests and fir-spruce-beech forests were assessed at comparable altitudes and exposures. Both types of extensivel...

This paper reviews the effects that windstorm-induced drastic changes (micro-climate, soil, vegetation, and ground structural heterogeneity) have on forest insect communities. In the current context of shady and CWD-deprived managed forests, windthrow gaps act as regional biodiversity hotspots by maintaining habitat continuity in a mosaic landscape...

Since prehistoric times, natural and man made fires have been important factors of natural disturbance in many forest ecosystems, like those on the southern slopes of the Alps. Their effect on scarce, endangered or stenotopic species and on the diversity of invertebrate species assemblages which depend on a mosaic of successional habitat stages, is...

An important goal of ecological compensation measures in agricultural areas is the conservation and enhancement of regional species diversity. However, some current European agri-environment schemes seem to be rather ineffective. A likely explanation is the lack of source populations in intensely cultivated landscapes. Remnants of natural and semin...

Ideally, an indicator for biodiversity is a linear correlate to the entity or aspect of biodiversity under evaluation. Different motivations for assessing entities or aspects of biodiversity lead to different value systems; their indicators may not correlate at all. For biodiversity evaluation in agricultural landscapes, three indices are proposed,...

On a continental basis, Cc3 larvae are reasonably distinct from those of C. mediterranea (Henry et al., 1999a), but are more easily confused with larvae of C. pallida, C. carnea and especially C. lucasina. Compared with C. mediterranea, Cc3 exhibits darker pigmentation of the dorsolateral stripe and displays a dark spot within the stripe that is us...

What was once considered a single Holarctic species of green lacewing, Chrysoperla carnea (Stephens), has recently been shown to be a complex of many cryptic, sibling species, the carnea species group, whose members are reproductively isolated by their substrate-borne vibrational songs. Because species in the complex are diagnosed by their song phe...

The Holarctic carnea-group of Chrysoperla green lacewings consists of numerous cryptic, sibling species, distinguished principally by vibrational courtship songs. A European member of this species-group, C. mediterranea (Hölzel), was originally diagnosed by its dark green coloration, red band across the front of the head, narrow wings, minute basal...

After the severe windthrow caused by the storm Vivian in 1990 in the Alps, political conflicts arose over the question whether clearing of the resulting gaps in the forest should be promoted and publicly subsidised. One argument against clearing was that uncleared windthrow areas would be better for the enhancement and conservation of biodiversity....

Storms are important disturbance factors in the development of forest ecosystems. They trigger definite changes in vegetation composition and hence also in the associated insect fauna. Three windthrow areas created by the storm Vivian in 1990 in alpine spruce forests were each subdivided into a cleared and an uncleared treatment. The abundance of t...

In a research project investigating the contribution of forest ecotone structures to regional arthropod biodiversity, the neuropteran fauna was assessed at five differently-structured forest edges and, for comparison, 50 m inside the forest. Arthropods were collected from February to November by means of pitfall traps, window (interception) traps a...

In agriculture, sustainability can be linked to ecological resilience. In view of present or imminent environmental changes in agricultural landscapes, the diversity of species and genotypes, particularly of potential beneficials and alternative prey, may become of increasing importance. However, the available methods and empirical data concerning...

Die Geschichte des Naturschutzes in seinen ersten hundert Jahren gleicht einer endlosen Reihe von Feuerwehrübungen: Rettung von Tier- und Pflanzenarten vor dem Aussterben, Bewahren von Biotopen und Landschaften in Schutzgebieten, fast immer in Eile und als Reaktion auf Eingriffe der nutzsuchenden Menschen. Ist Naturschutz im großen und ganzen erfol...

Based on a transect consisting of 19 identical trap stations in cultivated areas and seminatural habitats, the correlation of species numbers of higher taxonomic groups with total species numbers of flowering plants and arthropods per trap site was calculated. A total of 191214 invertebrate specimens and 2221 species of plants and animals were anal...

Numerous windthrows caused by the storm Vivian 1990 in Europe highlighted conflicting views on whether public money should be spent to clear windthrow areas. Enhancement of biodiversity, one of the prime arguments against clearing, was investigated in three regions in the Swiss Alps in pairwise comparisons between cleared and uncleared windthrow ar...

Evaluating biodiversity in agricultural areas requires two steps: (i) adequate measurement and (ii) pertinent interpretation. Since the whole spectrum of biodiversity in the sense of the Rio Convention cannot possibly be measured as such, adequate measurable correlates or surrogates have to be found. One possibility are standardized inventories to...

Mark-release-recapture experiments with both newly emerged and flight experienced Ips typographus L. were performed in a pine forest near Prague. Three concentric trap circles around the release site with a radius of 5 m, 200 m and 500 m, and intertrap distances of 6 m, 16 m and. maximally, 40 m, were installed with the intention of collecting all...

The existence of cryptic, sibling species, distinguished principally by vibrational courtship songs, has been confirmed for the carnea-group of Chrysoperla green lacewings in Europe and western Asia. One member of this species-group, C.lucasina (Lacroix), is characterized by several morphological traits as well, but its taxonomic validity has been...

Catches of six different groups of arthropods, collected in four habitat types, were analysed for the efficiency of two types of pitfall traps: plastic cups and plastic funnels. An ANOVA indicates influences of trap type, habitat and systematic group (spiders stand out) on capture success (Tab. 2). Correlation analysis of numbers captured per cm tr...

‘Edge permeability’ between habitat patches in a mosaic landscape of mixed intense agriculture and semi-natural areas was investigated with directional trap devices along field borders and in a 300-m long transect through crap fields, pasture, wetland and a dry meadow.Almost all identified arthropod species performaned population exchanges over the...

Brown lacewing eggs (Planipennia: Hemerobiidae) glued to the top of hairs of maize leaves can be seen as an intermediary evolutionary step between depositing the egg directly on the substrate (as in most neuropteroid families) and the protective behavioral adaptation of depositing the egg on a long thin pedicel (as e.g. in the Chrysopidae).