Elevation gradient affects the distribution and host utilisation of Zatypota anomala (Hymenoptera, Ichneumonidae) associated with mesh web weaving spiders (Araneae, Dictynidae)

The spatial distribution of parasitoids is closely linked to the distribution and ecological requirements of their hosts. Several studies have documented changes in the fauna composition of parasitoids in response to elevation, but data on parasitoids associated with spiders are missing. The koinobiont ichneumonid wasp Zatypota anomala is strictly specialised on spiders of the genus Dictyna (Dictynidae) in Europe. We examined the distribution of spiders of the family Dictynidae in forest ecotones in central Europe across a broad elevation gradient (110–1466 m a.s.l.). We checked the spiders for parasitism by Z. anomala. It was most abundant at the mid-elevations (median 712 m a.s.l., range 179–870 m a.s.l.). We identified four dictynid spider species as Z. anomala hosts. These were Dictyna arundinacea, Dictyna uncinata, Nigma flavescens, and Nigma walckenaeri. All four species and the genus Nigma were recorded as hosts for the first time. The parasitoids strongly preferred juvenile instars of their hosts. The body length differed between parasitised Dictyna and Nigma spiders (medians: 1.95 mm and 2.55 mm, respectively). The distribution of Dictyna and Nigma spiders overlapped along the elevation gradient, but parasitism incidence significantly differed between spider genera along the elevation gradient. Nigma was parasitized at lower elevations between 179–254 m a.s.l. and Dictyna at higher elevations between 361–870 m a.s.l. The phenology of Z. anomala is closely tied to the univoltine life strategy of its host spiders. The parasitoid female oviposits in autumn, and its offspring overwinter as larvae on the host, reach adulthood during spring, and pass the summer as an adult

The World Spider Trait database : a centralised global open repository for curated data on spider traits

Publisher Copyright: © The Author(s) 2021. Published by Oxford University Press.Spiders are a highly diversified group of arthropods and play an important role in terrestrial ecosystems as ubiquitous predators, which makes them a suitable group to test a variety of eco-evolutionary hypotheses. For this purpose, knowledge of a diverse range of species traits is required. Until now, data on spider traits have been scattered across thousands of publications produced for over two centuries and written in diverse languages. To facilitate access to such data, we developed an online database for archiving and accessing spider traits at a global scale. The database has been designed to accommodate a great variety of traits (e.g. ecological, behavioural and morphological) measured at individual, species or higher taxonomic levels. Records are accompanied by extensive metadata (e.g. location and method). The database is curated by an expert team, regularly updated and open to any user. A future goal of the growing database is to include all published and unpublished data on spider traits provided by experts worldwide and to facilitate broad cross-taxon assays in functional ecology and comparative biology. Database URL:https://spidertraits.sci.muni.cz/.Peer reviewe

Effect of the nutritional quality of primary food on the development, sex ratio, and size of a parasitoid in a quadri-trophic food web

This study explores the effect of nutritional composition on the fitness of consumers in a quadri-trophic food web. Specifically, we studied how enrichment of the food of fruit flies Drosophila melanogaster (Meigen, 1830) transfers to the spider Phylloneta impressa (L. Koch) (Theridiidae) and its parasitoid wasp, Zatypota percontatoria Mueller (Ichneumonidae). We reared fruit flies on balanced, protein-enriched, and lipid-enriched diets, and observed several fitness-related traits in both the predator and the parasitoid. In spiders, we did not find significant differences among treatments in their body size and the probability of building a cocoon web. In parasitoids, we failed to find significant differences among treatments in the time to wasp pupation, the duration of pupation, the length of the wasp tibia and pronotum, and the body mass. However, the sex ratio of hatched wasps differed significantly among treatments from the expected 1 : 1. In the balanced diet group, the majority of wasps were males. There was a significant positive relationship between the spider prosoma size and the length of the wasp fore wing. Our results suggest that the quality of the food of the primary consumer had little effect on the fitness of the organism at the fourth trophic level

New records of two spider-parasitoids of the genus Polysphincta (Hymenoptera, Ichneumonidae, Ephialtini) from Central Europe, with notes on their host interactions

A polysphinctine wasp Polysphincta longa, associated with the orb web building spider Araneus angulatus, was recorded for the first time in Slovakia. Further, the congener Polysphincta tuberosa was recorded in association with a new spider host Araneus sturmi. New distribution records of Polysphincta species from the Czech and Slovak Republics are presented. The final stage larva of both, P. longa and P. tuberosa, induced a specific alteration in web architecture: the spider constructed a unique 3D tangle of silk – so called “cocoon web” – to protect the parasitoid during the pupal stage. The host range of wasps belonging to the genus Polysphincta in Europe is discussed

Neunachweis der exotischen Speispinne Scytodes fusca (Araneae, Scytodidae) in Mitteleuropa aus Deutschland und der Slowakei

The spitting spider Scytodes fusca Walckenaer, 1837 is recorded for the first time in Central Europe from both Germany and Slovakia. The species was found in two localities, within the Botanical Garden in Bratislava (Slovakia), specifically from a heated greenhouse with high humidity, and the "Tropical Islands", a tropical holiday resort in Krausnick (Germany). It seems that this Pantropical species has probably been introduced here along with imported plants. A description of diagnostic characters, as well as figures, is given.Die Speispinne Scytodes fusca Walckenaer, 1837 konnte erstmals für Mitteleuropa in Deutschland und der Slowakei nachgewiesen werden. Die Funde stammen aus dem Botanischen Garten in Bratislava (Slowakei) sowie aus dem Freizeitbad "Tropical Islands" in Krausnick (Deutschland). Es wird vermutet, dass die pantropische Art durch Zierpflanzen eingeschleppt wurde. Die charakteristischen Merkmale der Art werden beschrieben und abgebildet

Data from: Biological control in winter: novel evidence for the importance of generalist predators

1. The role of generalist predators in pest control has been neglected because generalists are not able to track pest populations. Generalist predators are suggested to be important in spring before specialist predators become active. 2. Here, we show that some generalist predators are important even during winter, when the majority of arthropod pests and their enemies are dormant. We quantified the role of winter-active generalist predators on the suppression of pear psylla during winter using a discrete nonlinear model of an intraguild predation system. 3. To parameterize our model, we conducted a series of experiments on (i) functional responses, (ii) prey preferences and (iii) ontogenetic development and made observations on the population densities of spiders and potential prey. We ran the model for different winter scenarios, that is, for very cold and very warm winters. 4. Synthesis and applications. We found that winter-active predators considerably suppressed the pear psylla population. Predators exerted a stronger effect in a warmer winter than in a colder one. Orchard growers thus should avoid use of non-selective pesticides during this period and instead aim to support the community of generalist predators. Our results suggest more attention should be given to encouraging generalist predator populations in other systems, even in periods when crops are not producing

data

Measurements of functional response, body sizes, and potential pre