Theoretical developments are helping us to comprehend the basic parameters governing the dynamics of the interactions between generalist predators and their many pest and nonpest prey. In practice, however, inter- and intraspecific interactions between generalist predators, and between the predators and their prey, within multispecies systems under the influence of rapidly changing biotic and abiotic variables are difficult to predict. We discuss trade-offs between the relative merits of specialists and generalists that allow both to be effective, and often complementary, under different circumstances. A review of manipulative field studies showed that in approximately 75% of cases, generalist predators, whether single species or species assemblages, reduced pest numbers significantly. Techniques for manipulating predator numbers to enhance pest control at different scales are discussed. We now need to find ways of disentangling the factors influencing positive and negative interactions within natural enemy communities in order to optimize beneficial synergies leading to pest control.

Can generalist predators be effective biocontrol agents

Invasions by non-native ants are an ecologically destructive phenomenon affecting both continental and island ecosystems throughout the world. Invasive ants often become highly abundant in their introduced range and can outnumber native ants. These numerical disparities underlie the competitive asymmetry between invasive ants and native ants and result from a complex interplay of behavioral, ecological, and genetic factors. Reductions in the diversity and abundance of native ants resulting from ant invasions give rise to a variety of direct and indirect effects on non-ant taxa. Invasive ants compete with and prey upon a diversity of other organisms, including some vertebrates, and may enter into or disrupt mutualistic interactions with numerous plants and other insects. Experimental studies and research focused on the native range ecology of invasive ants will be especially valuable contributions to this field of study.

The Causes and Consequences of Ant Invasions

In the last 15 years understanding of the higher systematics of Araneae has changed greatly. Large classical superfamilies and families have turned out to be polyor paraphyletic; posited relationships were often based on sym­ plesiomorphies. In this brief review we summarize current taxonomic and phylogenetic knowledge and suggest where future efforts might profitably be concentrated. We lack space to discuss fully all the clades mentioned, and the cited numbers of described taxa are only approximate. Other aspects of spider biology have been summarized by Barth (7), Eberhard (47), Jackson & Parks (72), Nentwig (l05), Nyffeler & Benz ( 1 06), Riechert & Lockley ( 134), Shear ( 1 49) and Turnbull ( 160).

Systematics and Evolution of Spiders (Araneae)

Spiders as Biological Control Agents

The BAWBILT bases in Europe.- The Bawbilt Context in Europe.- The Directory of European Experts.- The Bawbilt Database.- Damage and Control of Bawbilt Organisms an Overview.- Bark Beetles.- Taxonomy and Systematics of Bark and Ambrosia Beetles.- Genetic Tools in Scolytid Research.- General Biology of Bark Beetles.- Chemical Ecology of Bark Beetles in a Complex Olfactory Landscape.- Host Resistance to Bark Beetles and Its Variations.- Fungal Associates of European Bark Beetles With Special Emphasis on the Ophiostomatoid Fungi.- Research on Parasitoids and Predators of Scolytidae - A Review.- Pathogens in Bark Beetles.- Bark Weevils.- Taxonomy and Systematics of Bark Weevils.- General Biology and Life Cycles of Bark Weevils.- Semiochemicals in the Life of Bark Feeding Weevils.- Hylobius Abietis - Host Utilisation and Resistance.- Fungi Associated With Hylobius Abietis and Other Weevils.- Parasitoids, Predators, Nematodes and Pathogens Associated with Bark Weevil Pests.- Damage, Control and Management of Weevil Pests, Especially Hylobius Abietis.- Buprestids and Longhorns.- Biology, Ecology and Economic Importance of Buprestidae and Cerambycidae.- Natural Enemies of Cerambycidae and Buprestidae Infesting Living Trees.- "Non-Coleopteran" Bawbilt organisms.- "Non-Coleopteran Insects".- Research needs and priorities for Europe.- General Conclusions and Research Priorities for Bawbilt Organisms in Europe.

Bark and Wood Boring Insects in Living Trees in Europe, a Synthesis

Bemerkenswerte Spinnenfunde in Wiesen und Getreidefeldern bei Zürich

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Eine Notiz über borkenkäfertötende Spinnen

Abstract. In this paper, we present an update on our knowledge on egg predation (oophagy) by spiders. Based on a survey of 233 reports, ghost spiders (Anyphaenidae), lynx spiders (Oxyopidae), jumping spiders (Salticidae), and yellow sac spiders (Cheiracanthiidae) were the most prominent groups of spiders engaged in oophagy. Around 75% of the reports referred to the consumption of lepidopteran and spider eggs worldwide. Another 10% referred to the consumption of eggs/embryos of anurans – especially predation upon embryos of glass frogs (Centrolenidae) by spiders from the families Anyphaenidae and Trechaleidae in the Neotropics. The remaining 17% included rare instances of feeding on eggs of coleopterans, dermapterans, dipterans, heteropterans, homopterans, hymenopterans, acarids, neuropterans, opilionids, and squamates. Our study demonstrates that oophagy in spiders is much more widespread than previously thought, both geographically and taxonomically. The finding that spiders feed on eggs/embryos from so many different invertebrate and vertebrate taxa is novel.

Oophagy in spiders: consumption of invertebrate and vertebrate eggs

Abstract. In this review, we report on harvestmen and spiders feeding on fungi, fruits, and seeds. Fungivory in harvestmen is widespread, with most reports referring to tropical species in the family Sclerosomatidae, which consume mainly small forest mushrooms (families Marasmiaceae and Mycenaceae). In contrast, consumption of fungal material by spiders apparently occurs only if airborne spores trapped in the viscid threads of orb-webs (e.g., Araneidae and Tetragnathidae) are ingested along with old webs prior to the construction of new webs. Consumption of fruit pulp by harvestmen is also widespread, with several records of Leiobunum spp. (Sclerosomatidae) feeding on Rubus spp. berries and other lipid-poor fruits in the Holarctic region. In Neotropical forests, harvestmen in the families Cosmetidae and Gonyleptidae feed on lipid-poor pulp of fallen fruits. Among spiders, we document several cases of synanthropic species opportunistically feeding on fruit waste (e.g., pieces of banana, papaya, watermelon, or orange pulp) inside houses or disposed in yards. Only one case of a spider feeding on a wild fruit in the field was found in our search. Finally, we report several cases of harvestmen and spiders feeding on elaiosomes or arils (i.e., lipid-rich seed appendages). In conclusion, harvestmen consume mushrooms, fruit pulp, seeds, and seed appendages more frequently than spiders probably because they are “solid food feeders”, which means they can ingest solid tissues by biting off small pieces. In turn, spiders are “fluid feeders” and feed on vegetable matter most frequently in the form of fluids (e.g., nectar, stigmatic exudate, plant sap, and honey dew), rather than fungal or plant tissues.

Fungus and fruit consumption by harvestmen and spiders (Opiliones, Araneae): the vegetarian side of two predominantly predaceous arachnid groups

In this paper the findings of a global literature and social media survey of spider mycoses are presented. Our survey revealed that spider mycoses occur in the geographic belt between latitude 78° N and 52° S, and that more than 40 out of the known 132 spider families (>30%) are attacked by fungal pathogens. Jumping spiders (Salticidae), cellar spiders (Pholcidae), and sheet web spiders (Linyphiidae) are the families most frequently reported to be attacked by fungal pathogens (combined >40% of all reported cases). Ninety-two percent of the infections of spiders can be attributed to pathogens in the order Hypocreales / phylum Ascomycota (i.e., almost exclusively families Cordycipitaceae and Ophiocordycipitaceae). Within the Hypocreales, the anamorph genus Gibellula is an historically species-rich and widespread genus of specific spider-pathogenic fungi. For ≈70 species of spider-pathogenic fungi their hosts could be identified at least to family level. The data presented here reaffirms the findings of previous studies that spider-pathogenic fungi are most common and widespread in tropical and subtropical forested areas, with free-living cursorial hunters (especially Salticidae) being most frequently infected. Free-living cursorial hunters (especially Salticidae) and subterranean cellar spiders (Pholcidae) are the most frequently fungus-infected spiders in North America, whereas web-weavers (especially Linyphiidae and Pholcidae) are the most common spider hosts in Europe. Our survey implies that spider- pathogenic fungi are an important mortality factor of spiders which has hitherto been underestimated.

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Martin Nyffeler

Papers

Bemerkenswerte Spinnenfunde in Wiesen und Getreidefeldern bei Zürich

Eine Notiz über borkenkäfertötende Spinnen

Oophagy in spiders: consumption of invertebrate and vertebrate eggs

Fungus and fruit consumption by harvestmen and spiders (Opiliones, Araneae): the vegetarian side of two predominantly predaceous arachnid groups

Diversity of spider families parasitized by fungal pathogens: a global review