Aim Arthropods as vertebrate predators is a generally overlooked aspect in ecology due to the cryptic nature of these events, the relatively small size of arthropods and the difficulty in finding published data. This study represents the largest global assessment of arthropods preying on vertebrates to provide a conceptual framework, identify global patterns and provide a searchable database. Location Global. Time period Present. Major taxa studied Arthropods and vertebrates. Methods A systematic literature review was conducted. Results Over 1,300 recorded observations were collated from 89 countries. Arthropod predators were from 6 classes and 83 families. Vertebrate prey were from 5 classes and 163 families. Spiders represented over half of all predatory events and were the main predator for all vertebrates except birds, which were mostly preyed upon by praying mantises. Forty percent of all prey were amphibians, specifically frogs. Depredated reptiles were nearly all lizards, half of mammal prey were bats, nearly a third of fish were Cypriniformes and half of bird prey were passerines. Predation by spiders was mainly documented from the U.S., Brazil and Australia, and biased mostly everywhere except the U.S.; insect predatory events were mainly documented from Europe, Australia and the Americas, and biased toward North America; amphibian events were mainly from the Americas and strongly biased everywhere, except for the U.S. and Australia; reptiles events were recorded mostly from the Americas and Australia, and biased towards the U.S. and Australia; predation on birds were mainly from the Americas, Australia and Europe, and biased towards Central America and Europe; and mammal events were mostly reported from North and Central America, Australia, and Asia, and strongly biased everywhere except Brazil. Main conclusions This study demonstrates that arthropods are underestimated predators of vertebrates. Recognizing and quantifying these predator–prey interactions is vital for identifying patterns and the potential impact of these relationships on shaping vertebrate populations and communities.

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Seedling emergence in plant communities depends on the composition in the soil seed bank, in combination with species-specific responses to the environment. It is generally assumed that this juvenile transition, known as the recruitment niche, is a crucial filter that determines species’ distributions and plant community assemblies. The relative importance of this filter, however, has been widely debated. Empirical descriptions of the recruitment niche are scarce, as most field studies focus on environmental effects at later life stages. In this study, we examine the importance of the recruitment niche for predicting plant communities across a hydrological gradient in a disturbed and undisturbed area in Lake Schmiechen, Baden-Württemberg, Germany. We combine a seed bank experiment, measuring germination in water basins under standardized conditions and different water levels, with field observations of plant communities along a hydrological gradient in plowed and undisturbed transects in a former agricultural wetland. We find that hydrology consistently predicted plant community composition in both the germination experiment and in the field. The hydrological recruitment niches measured in the seed bank experiment correlated with the hydrological niche in both the plowed and undisturbed area, with slightly stronger correlation in the plowed area. We explain the latter by the fact that the seed bank experiment most closely resembles the plowed area, whereas succession and competitive interactions become more important in the undisturbed area. Our results support the view that the recruitment niche is an important driver of species composition, in both the plowed and undisturbed area. Recognizing the recruitment niche and the response of seeds within a seed bank to environmental gradients and anthropogenic disturbance is necessary to understand and predict future plant community composition.

The role of invertebrate predation in shaping vertebrate communities is often overlooked. This is evident with predaceous diving beetles (Coleoptera: Dytiscidae), which are often the top predator in many aquatic freshwater habitats. During weekly monitoring of a reintroduction for an endangered frog, a group of a dozen adult diving beetles were encountered attacking and quickly dismembering and consuming a tadpole. A single adult diving beetle was also discovered burrowing its head inside and consuming a tadpole approximately 3–4 times its size by seemingly piercing its prey to suck out its liquefied remains. This is in contrast with the well known behaviour of adult dytiscids, which involves tearing prey into small pieces with their chewing mouthparts. Although dytiscids are known to occasionally consume vertebrates such as tadpoles, adults are typically considered scavengers, and this communal predatory behaviour and feeding method have not previously been documented. Moreover, over 80% of the tadpoles in the monitored site were found in ponds with no beetles and despite representing only a quarter of all ponds, half of the tadpoles across the landscape were in ponds free of diving beetles, demonstrating a possible influence of diving beetles on tadpoles. These observations may have implications for amphibian conservation since management efforts are not typically concerned with naturally occurring ubiquitous threats such as those from small invertebrate predators, as it has rarely been observed in nature. Although amphibian conservation plans expect some losses from natural predation, diving beetles may affect conservation efforts such as captive breeding and reintroductions with populations where every individual is critical to success.

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Species richness is the most commonly used metric to quantify biodiversity. However, examining dark diversity, the group of missing species which can potentially inhabit a site, can provide a more thorough understanding of the processes influencing observed biodiversity and help evaluate the restoration potential of local habitats. So far, dark diversity has mainly been studied for specific habitats or large‐scale landscapes, while less attention has been given to variation across broad environmental gradients or as a result of local conditions and biotic interactions. In this study, we investigate the importance of local environmental conditions in determining dark diversity and observed richness in plant communities across broad environmental gradients. Using the ecospace concept, we investigate how these biodiversity measures relate to abiotic gradients (defined as position), availability of biotic resources (defined as expansion), spatiotemporal extent of habitats (defined as continuity), and species interactions through competition. Position variables were important for both observed diversity and dark diversity, some with quadratic relationships, for example, plant richness showing a unimodal response to soil fertility corresponding to the intermediate productivity hypothesis. Interspecific competition represented by community mean Grime C had a negative effect on plant species richness. Besides position‐related variables, organic carbon was the most important variable for dark diversity, indicating that in late‐succession habitats such as forests and shrubs, dark diversity is generally low. The importance of highly competitive species indicates that intermediate disturbance, such as grazing, may facilitate higher species richness and lower dark diversity.

Gastropods are known to secrete mucus for a variety of purposes, including locomotion, reproduction, adhesion to surfaces and lubrication. A less commonly known function of mucus secretion in this group involves its use as a defence against predation. Amongst the terrestrial slugs, mucus that serves this particular purpose has been studied for only a handful of species under laboratory conditions, where it is thought to be produced to make individuals unpalatable or difficult to consume. However, the mechanisms of how these defensive secretions operate and their effectiveness in deterring predation in the natural world have not been described in much detail. In this study, we provide evidence of adhesive mucus secretions in the red triangle slug (Triboniophorus graeffei) as an adaptation against predation. Field observations of a large red‐eyed green tree frog (Litoria chloris) trapped in the mucus secretions of a nearby T. graeffei revealed that this mucus serves to incapacitate predators rather than just an overall deterrence. Mechanical stimulation of T. graeffei under laboratory conditions revealed that adhesive secretions were produced from discrete sections of the dorsal surface when disturbed, leading to the production of a highly sticky and elastic mucus that was unlike the thin and slippery mucus used during locomotion. The adhesiveness of the defensive secretions was strengthened and reactivated when in contact with water. This appears to not only be the first description of defensive mucus production in this slug species but one of the first natural observations of slug secretions incapacitating a relatively large vertebrate. The biomechanical properties of this mucus and its ability to maintain and strengthen its hold under wet conditions make it potentially useful in the development of new adhesive materials.

In highly ephemeral freshwater habitats, predatory vertebrates are typically unable to become established, leaving an open niche often filled by macroinvertebrate predators. However, these predators are faced with the challenge of finding sufficient food sources as the rapid rate of desiccation prevents the establishment of extended food chains and limits the number of prey species present. It could therefore be advantageous for predators to synchronize their phenology with that of their prey within sites of extreme ephemerality. We report the first case of adult diving beetles (Hydaticus parallelus) ovipositing their eggs within spawn of an amphibian species (sandpaper frog, Lechriodus fletcheri). This behavior was found among several pools used by L. fletcheri for reproduction. Beetle eggs oviposited in frog spawn were found to hatch within 24 h of the surrounding L. fletcheri eggs, with the larvae becoming voracious consumers of the hatched tadpoles. Although it has yet to be established experimentally whether this is an adaptive behavior, the laying of eggs among potential future tadpole prey in this instance should confer significant fitness benefits for the offspring upon hatching, ensuring that they are provided an immediate source of food at the start of their development and potentially throughout. This oviposition behavior might be common among diving beetles and could form a significant predatory threat for amphibians with a free‐swimming larval stage in ephemeral freshwater habitats.