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Figure 2 in Spiders that prey on jumping spiders (Araneae: Salticidae)

Figure 2. Theridiids of the genus Ariamnes feeding on various arthropods. 1, Feeding on another Ariamnes. 2, Feeding on a sparassid spider of the genus Gnathopalystes Rainbow 1899. 3, Feeding on a Green Tree Ant, Oecophylla smaragdina. 4, Feeding on a tetragnathid of the genus Leucauge White 1841. 5, Feeding on a tetragnathid of the genus Tetragnatha Latreille 1804. 6, Feeding on a thomisid of the genus Thomisus Walckenaer 1805. Photographs by Abhijith A. P. C.

Figure 1 in Portia cf. labiata (Araneae: Salticidae: Spartaeini) as predator and prey of cellar spiders (Araneae: Pholcidae: Crossopriza) in Karnataka, India

Figure 1. Female Portia representing three species that have been found in India. 1, P. albimana, Kundannor, Maradu, Ernakulam, Kerala, India (21 JUL 2013). 2, P. albimana, Halanayakanahalli, Karnataka, India (8 MAY 2021). 3, P. fimbriata, Daintree Forest, Queensland, Australia (9 DEC 2018). 4, P. labiata, Singapore (17 NOV 2021). 5, P. labiata, Malaysia (SEP 2019). 6, P. labiata with spider prey, Penang, Malaysia (FEB 2018). Species names have not been confirmed by microscopic examination. Photo credits (all from iNaturalist): 1, Sunny Josef; 2, Thomas Job; 3, martisma; 4, budak; 5-6, Richard Ong. Photographs used under either a CC BY 4.0 license (1), or a CC BY-NC 4.0 license (2-6).

Figure 3 in Portia cf. labiata (Araneae: Salticidae: Spartaeini) as predator and prey of cellar spiders (Araneae: Pholcidae: Crossopriza) in Karnataka, India

Figure 3. Female Portia cf. labiata near her nest and emergent (second instar) young. 1, Dorsal view of female on vertical wall. 2, Female beneath her nest. 3, Female clinging to her nest. Note emergent young above the nest. 4, Female concealed by debris, suspended with silk lines (detail of 5). 5, Female position in debris (yellow rectangle), near nest (arrow). 6-7, Two more views of female at nest, with emergent young. 8, Detail of emergent Portia above nest. 9-11, Three views of an emergent Portia feeding on a small, immature Crossopriza. Photographs by Abhijith A. P. C., taken at his Indraprastha Organic Farm, Kalalwadi Village, Karnataka, India.

Figure 4 in Spiders that prey on jumping spiders (Araneae: Salticidae)

Figure 4. Theridiid spiders feeding on other spiders. 1-2, Rhomphaea feeding on a captured araneid spider of the genus Eriovixia Archer 1951. 3-4, Rhomphaea with a captured tetragnathid spider, Leucauge fastigata (Simon 1877). 5, Kleptoparasitic theridiid of the genus Argyrodes Simon 1864 that has been feeding on a salticid (below). Photographs by Abhijith A. P. C.

Figure 8 in Spiders that prey on jumping spiders (Araneae: Salticidae)

Figure 8. Female oxyopid spider of the genus Hamadruas Deeleman-Reinhold 2009 feeding on a penultimate male salticid of the genus Hyllus. Photographs by Abhijith A. P. C.

Figure 2 in Portia cf. labiata (Araneae: Salticidae: Spartaeini) as predator and prey of cellar spiders (Araneae: Pholcidae: Crossopriza) in Karnataka, India

Figure 2. Adult female Portia cf. labiata. 1, Portia (at right) watching a nearby pholcid spider of the genus Crossopriza. 2-4, Three sequential images of a Portia feeding on a captured Crossopriza. Photographs by Abhijith A. P. C., taken at his Indraprastha Organic Farm, Kalalwadi Village, Karnataka, India.

opencc-by-nd-4.0Aug 2021View details →

Figure 1. Female Tutelina elegans with prey. 1 in Fluorescence in jumping spiders of the genus Tutelina (Araneae: Salticidae: Dendryphantini)

Figure 1. Female Tutelina elegans with prey. 1, Feeding on a large ant (Formica), Occoquan Bay National Wildlife Refuge, Woodbridge, Virginia, 4 SEP 2016. 2, Feeding on midge (Chironomus), Bear Creek Lake State Park, Cumberland, Virginia, 4 OCT 2020. Photographs by Judy Gallagher, used under a Creative Commons Attribution 2.0 Generic (CC BY 2.0) license.

opencc-zeroMar 2022View details →

Quantifying the relationship between prey density, livestock and illegal killing of leopards

Many large mammalian carnivores are facing population declines due to illegal killing (e.g., shooting) and habitat modification (e.g., livestock farming). Illegal killing occurs cryptically and hence is difficult to detect. However, reducing illegal killing requires a solid understanding of its magnitude and underlying drivers, while accounting for the imperfect detection of illegal killing events. Despite the importance of illegal killing of large carnivores in comparison with other causes of mortality, its relationship with potential drivers such as livestock density and wild prey abundance is rarely described. Using ranger-collected data (2007-2019) of leopard killing events and data on covariates (livestock density, wild prey abundance, road length, protected area size, elevation) across Iran, we applied a single-visit N-mixture model to jointly model variation in detection probability and expected annualized number of leopard killing events. Over the study period, we estimated 428 leopard mortalities (95% CI 184–1014), which was 45% larger than the observed number. Expected intensity of leopard killing was positively related to protected area size, livestock density and wild prey abundance. Detection of leopard killing was higher in areas with more developed road networks. Synthesis and applications Ranger based monitoring data on poaching of carnivores are cost-effective, but traditional analysis does not take into account imperfect detection. We show that innovative statistics (single-visit N-mixture modeling) can reliably quantify poaching events and address their drivers, at large geographical scales. We used the example of the Persian leopard across Iran, but our approach is also applicable to understand killing dynamics of other species. Results suggest that a high frequency of leopard killing is likely to occur in areas with > 100 livestock per km2 and > 450 individuals of wild prey per km2. This highlights the need for improved management of livestock grazing and effective measures around high-risk protected areas to mitigate human-leopard conflict and reduce killing of leopards.

opencc-by-4.0Apr 2022View details →

Fig. 1 in Diet, Prey Selection and Biomass Consumption of the Great Cormorant (Phalacrocorax carbo) in Algeria

Fig. 1. Geographical location of Beni-Haroun Dam Lake in Algeria.

opencc-zeroDec 2021View details →

Data from: Prey encounters and spatial memory influence use of foraging patches in a marine central place forager

Given the patchiness and long-term predictability of marine resources, memory of high-quality foraging grounds is expected to provide fitness advantages for central place foragers. However, it remains challenging to characterise how marine predators integrate memory with recent prey encounters to adjust fine-scale movement and use of foraging patches. Here, we used two months of movement data from harbour seals (Phoca vitulina) to quantify the repeatability in foraging patches as a proxy for memory. We then integrated these data into analyses of fine-scale movement and underwater behaviour to test how both spatial memory and prey encounter rates influenced the seals' Area Restricted Search (ARS) behaviour. Specifically, we used one month's GPS data from 29 individuals to build spatial memory maps of searched areas, and archived accelerometry data from a subset of five individuals to detect prey catch attempts, a proxy for prey encounters. Individuals were highly consistent in the areas they visited over two consecutive months. Hidden Markov Models showed that both spatial memory and prey encounters increased the probability of seals initiating ARS. These results provide evidence that predators use memory to adjust their fine scale movement and this ability should be accounted for in movement models.

opencc-zeroApr 2022View details →

Linking agri-environment scheme habitat area, predation and the abundance of chick invertebrate prey to the nesting success of a declining farmland bird

Across Europe, farmland bird populations have continued to decline since the 1970s owing to the intensification of farming practices. Studies of such declines have tended to focus specifically on either the impacts of habitats (nesting and foraging), nest predators or prey availability on bird demographics. The study presented here provides new insights into the relative effects of each of these factors on Yellowhammer nest survival. The Yellowhammer was selected for this study as it is a UK red-listed bird species whose population is in decline across much of Europe. We use a long-term dataset of 147 nests, monitored between 1995 and 2007, to provide an insight into how Yellowhammer nest survival is influenced by nesting habitat (nest concealment and nest height), foraging habitats (habitat coverage within 100 m of nests), the removal of nest predators (Magpie Pica pica abundance as an inverse measure of avian predator removal through gamekeeping) and food availability (measured with a D-vac invertebrate suction sampler). Our results indicated that Yellowhammer hatching success was negatively related to the coverage of spring agri-environment scheme habitats, a group which represents invertebrate-rich agri-environment habitats, but hatching success increased with nest height. Fledging success was positively related to the coverage of the seed-rich habitat Wild Bird Seed mixture. The farm-level abundance of Yellowhammer chick-food invertebrates declined over the study period. Our results highlight the importance of simultaneously considering multiple agents that shape avian breeding success, i.e. their ability to produce offspring, to inform conservation management. Our key finding for land managers relates to the positive relationship between the proportion seed rich foraging habitat within the Yellowhammer's average foraging range and Yellowhammer fledging success, which shows that a habitat intended primarily to provide winter food resources is also important to breeding birds. Chick food abundance in this habitat was, however, similar to broadleaf and cereal crops. We recommend that this habitat should be provided near to potential Yellowhammer nesting sites and adjacent to invertebrate-rich agri-environment scheme habitats such as beetle banks and conservation headlands to further boost invertebrate resources for a declining farmland bird.

opencc-zeroMay 2022View details →

Metabarcoding prey Araneus diadematus: TREE platform

Trophic interactions may strongly depend on body size and environmental variation, but this prediction has been seldom tested in nature. Many spiders are generalist predators that use webs to intercept flying prey. The size and mesh of orb webs increases with spider size, allowing a more efficient predation on larger prey. We studied to this extent the orb-weaving spider Araneus diadematus inhabiting forest fragments differing in edge distance, tree diversity and tree species. These environmental variables are known to correlate to insect composition, richness and abundance. We anticipated these forest characteristics to be a principle driver of prey consumption. We additionally hypothesised them to impact spider size at maturity and expect shifts towards larger prey-size distributions in larger individuals independently from the environmental context. We quantified spider diet by means of metabarcoding of nearly 1000 A. diadematus from a total of 53 forest plots. This approach allowed a massive screening of consumption dynamics in nature, though at the cost of identifying the exact prey identity, as well as their abundance and putative intraspecific variation. Our study confirmed A. diadematus as a generalist predator, with more than 300 prey ZOTUs detected in total. At the individual level, we found large spiders to consume fewer different species, but adding larger species to their diet. Tree species composition affected both prey species richness and size in the spider's diet, although tree diversity per se had no influence on the consumed prey. Edges had an indirect effect on the spider diet as spiders closer to the forest edge were larger and therefore consumed larger prey. We conclude that both intraspecific size variation and tree species composition shape the consumed prey of this generalist predator.

opencc-zeroMay 2022View details →

Does prey scarcity increase the risk of wolf attacks on domestic dogs?

Gray wolf (Canis lupus) predation on domestic dogs (Canis familiaris) is a considerable wolf-human conflict issue in several regions of Europe and North America but has not been well documented in the scientific literature. Livestock depredations by wolves may be related to the abundance of wild prey. Regardless of the presumed motivations of wolves for attacking dogs (likely due to interference competition and predation), the abundance of wild prey populations may also influence the risk of wolf attacks on dogs. We examined whether the annual number of tatal attacks by wolves on dogs was related to the abundance of primary prey, including wild boar (Sus scrofa) and roe deer (Capreolus capreolus) in Estonia, as well as the abundance of moose (Alces alces) in Finland. Statistical models resulted in significant negative relationships, thus providing evidence that the risk of attacks in both house yards (Estonia) and hunting situations (Finland) was highest when the density of wild prey was low. Wild ungulates cause damage to agriculture and forestry, but they seem to mitigate conflicts between wolves and humans; therefore, it is necessary to develop a holistic, multispecies management approach in which the importance of wild ungulates for large carnivores is addressed.

opencc-zeroMay 2022View details →

RNA allows identifying the consumption of carrion prey

Facultative scavenging by predatory carnivores is a prevalent but frequently underestimated feeding strategy. DNA-based methods for diet analysis, however, do not allow to distinguish between scavenging and predation, thus, the significance of scavenging on population dynamics and resource partitioning is widely unknown. Here, we present a methodological innovation to differentiate between scavenging and fresh prey consumption using prey RNA as a target molecule. We hypothesized that the rapid post-mortem breakdown of RNA in prey tissue should lead to a significantly lower detection probability of prey RNA than DNA when carrion rather than fresh prey is consumed. To test this hypothesis, ground beetles (Pseudoophonus rufipes (De Geer)) were offered either fresh or one-day-old dead Drosophila melanogaster fruit flies (carrion). The detectability of prey RNA and DNA in the beetles' regurgitates was assessed with diagnostic Drosophila-specific RT-PCR and PCR assays at 0, 6, 12, 24 and 48 hours post-feeding. After fresh fly consumption, prey RNA and DNA were detectable equally well at all times. When carrion prey was consumed, the detection strength of prey RNA immediately after feeding was significantly lower than that of prey DNA and reached zero in most samples within 6 hours of digestion. Our findings provide evidence that prey RNA allows distinguishing between the consumption of fresh and scavenged prey, thereby overcoming a long-known weakness of molecular diet analysis. The assessment of prey RNA offers a generally applicable approach for examining the importance of scavenging in food webs to unravel its functional consequences for populations, communities, and ecosystems.

opencc-zeroJun 2022View details →

Use of road underpasses by mammals and a monitor lizard in eastern Australia and consideration of the prey-trap hypothesis

Road networks continue to expand globally with predictable effects on ecological systems. Research into the effectiveness of road underpasses and overpasses for wildlife has been concentrated in North America and Europe. In Australia, most studies of underpasses have been of relatively short duration and without reference sites to give context to the measured rates of use. We studied 5–7 road underpasses at two locations in eastern Australia over 2–3 years, comparing camera trap detections of animals in underpasses with those at nearby forest sites. Three species of large macropod (wallabies and kangaroos) were frequently detected in the underpasses, with some underpasses traversed 1–4 times per week, and in many cases exceeded detections in the forest. The lace monitor (Varanus various) was detected in all underpasses, often once per week during spring and summer, and infrequently in the forest. At each location a different small macropod species, including one regionally threatened, showed a higher probability of detection in one underpass compared to several of the forest sites. The vulnerable koala (Phascolartos cinereus) was detected infrequently in underpasses and in the adjoining forest. The short-beaked echidna (Tachyglossus aculeatus) had a high probability of detection in a single underpass. The 'prey-trap hypothesis' postulates that predators will exhibit increased activity at underpasses as a consequence of prey being funnelled. We found the red fox (Vulpes vulpes) had high activity in some underpasses. However, its activity coincided less than expected with the activity of the mammals most at risk to it. Our results provide no consistent support for the 'prey-trap hypothesis'. Instead, our study confirms the generic value of underpasses for a range of medium-large mammals as well as one large reptile. Habitat adjoining underpasses exerts a strong influence on their use and requires greater consideration to maximise underpass use.

opencc-zeroJun 2022View details →

Cross-continental comparison of parasite communities in a wide-ranging carnivore suggests associations with prey diversity and host density

Parasites are integral to ecosystem functioning yet often overlooked. Improved understanding of host-parasite associations is important, particularly for wide-ranging species for which host range shifts and climate change could alter host-parasite interactions and their effects on ecosystem function. Among the most widely distributed mammals with diverse diets, grey wolves (Canis lupus) host parasites that are transmitted among canids and via prey species. Grey wolf-parasite associations may therefore influence the population dynamics and ecological functions of both wolves and their prey. Our goal was to identify large-scale processes that shape host-parasite interactions across populations, with the grey wolf as a model organism. By compiling data from various studies, we examined the faecal prevalence of gastrointestinal parasites in six wolf populations from two continents in relation to wolf density, diet diversity, and other ecological conditions. As expected, we found that the faecal prevalence of parasites transmitted directly to wolves via contact with other canids or their excreta was positively associated with wolf density. Contrary to our expectations, the faecal prevalence of parasites transmitted via prey was negatively associated with prey diversity. We also found that parasite communities reflected landscape characteristics and specific prey items available to wolves. Several parasite taxa identified in this study, including hookworms and coccidian protozoans, can cause morbidity and mortality in canids, especially in pups, or in combination with other stressors. The density-prevalence relationship for parasites with simple lifecycles may reflect a regulatory role of gastrointestinal parasites on wolf populations. Our result that faecal prevalence of parasites was lower in wolves with more diverse diets could provide insight into the mechanisms by which biodiversity may regulate disease. A diverse suite of predator-prey interactions could regulate the effects of parasitism on prey populations and mitigate the transmission of infectious agents, including zoonoses, spread via trophic interactions.

opencc-by-4.0Jun 2022View details →

Trans- and Within-Generational Developmental Plasticity May Benefit the Prey but Not Its Predator during Heat Waves

Dataset of the results in the article: Trans- and Within-Generational Developmental Plasticity May Benefit the Prey but Not Its Predator during Heat Waves in Biology. https://doi.org/10.3390/biology11081123 This research was funded by the Austrian Science Fund (FWF).

opencc-zeroJun 2022View details →

Prey naiveté alters the balance of consumptive and non-consumptive predator effects and shapes trophic cascades in freshwater plankton

Predators drive trophic cascades by reducing prey biomass and altering prey traits, selecting for prey that exhibit constitutive and induced anti-predator defenses that decrease susceptibility to consumption. These defense traits are often costly, generating a tradeoff between consumptive (CEs) and non-consumptive predator effects (NCEs). The ecological and evolutionary experience that prey share with a given predator may determine their position along this tradeoff curve, affecting the nature and strength of top-down control of ecosystems. Conceptual models predict that predator-experienced prey suffer greater NCEs than predator-naive prey, which suffer stronger CEs and total predator effects (CEs + NCEs), but this has not been tested in diverse prey communities. We tested these predictions by comparing the effects of predation (CEs + NCEs) and predation risk (NCEs only) of planktivorous fish on food web structure in pond mesocosms with diverse natural communities of either predator-naive or predator-experienced zooplankton. Contrary to expectations, top-down control of zooplankton and phytoplankton biomass was strengthened by prey community experience: in systems with experienced relative to naive zooplankton communities both predation risk (NCEs only) and predation (CEs + NCEs) had stronger effects on zooplankton prey biomass and trophic cascades were twice as strong. These results show that the ecological and evolutionary experience of diverse prey communities alters the balance of consumptive and non-consumptive predator effects and influences trophic cascade strength.

opencc-zeroJul 2022View details →

Data from: Large trees and forest heterogeneity facilitate prey capture by California spotted owls

Predators are among the most threatened animal groups globally, with prey declines contributing to their endangerment. However, assessments of the habitat conditions that influence the successful capture of different prey species are rare, especially for small, cryptic predators. Accordingly, most predator conservation plans are based on the relative importance of habitats inferred from coarse-scale <a name="_Hlk99628060"></a>studies that do not consider habitat features contributing to hunting success, which can vary among prey species. To address this limitation, we integrated high-resolution GPS tracking and nest video monitoring to characterize habitat features at prey capture locations during the nestling provisioning stage for the Spotted Owl (Strix occidentalis) a small, cryptic predator that has been at the center of a decades-long forest management conflict in western North America. When all prey species were considered collectively, males provisioning nests tended to capture prey: (i) in areas with more large-tree forest, (ii) in areas with more medium trees/medium canopy forest, and (iii) at edges between conifer and hardwood forests. However, when we considered the owl's two key prey species separately, males captured woodrats (Neotoma fuscipes) and Humboldt flying squirrels (Glaucomys oregonensis) in areas with markedly different habitat features. Our study provides clarity for forest management in mixed-ownership landscapes because different prey species achieve high densities in different habitat types. Specifically, our results suggest that promoting large trees, increasing forest heterogeneity, and creating canopy gaps in forests with medium trees/high canopy cover could benefit Spotted Owls and their prey, which has the ancillary benefit of enhancing forest resilience. Combining high-resolution GPS tagging with video-based information on prey deliveries to breeding sites can strengthen conservation planning for small predators by more rigorously defining those habitat features that are associated with successful prey acquisition.