Common Predators Research Articles

Experimental laboratory tests of short-term habitat selection by hatchery-reared juvenile red drum (Sciaenops ocellatus)

Structured estuarine habitats enhance the survival and growth of wild juvenile fishes by mediating density-dependent processes. However, the habitat selection behavior of hatchery-reared fishes upon release to the wild is not well understood. The red drum (Sciaenops ocellatus) is a highly sought-after, estuarine-dependent sportfish and the subject of stock enhancement efforts along the southeastern US Atlantic and Gulf coasts. We investigated the habitat associations of hatchery-reared red drum using experimental mesocosms intended to mimic the habitat types available at or nearby typical release sites in South Carolina, USA. Specifically, we presented juvenile red drum (overall mean ∼ 60 mm standard length) with a choice between salt marsh vegetation (Spartina alterniflora) and oyster shell in the presence and absence of a common estuarine predator (blue crab, Callinectes sapidus). Red drum more commonly associated with oyster shell over Spartina in both the presence and absence of a blue crab predator. Oyster shell habitat tended to be favored even when the location of the free-ranging blue crab predator was taken into account. Our results provide evidence that oyster shells, representative of a healthy restored or natural oyster reef, may be preferentially utilized by hatchery-reared red drum during the period immediately following release. Further investigation of post-release behaviors, including field-based experimental studies focusing on hatchery-reared red drum, is necessary to determine if the patterns of habitat selection behavior documented here have implications for post-release survival or mortality.

Red-backed shrike (Lanius collurio) versus common cuckoo (Cuculus canorus): An example of ineffective cuckoo-hawk mimicry.

The red-backed shrike (Lanius collurio) used to be one of the most common hosts of the common cuckoo (Cuculus canorus). Nevertheless, during the last 30 years, there is increasing evidence from Central Europe that the occurrence of cuckoo chicks in shrike nests has become scarcer, and that in some locations they have disappeared completely. Multiple hypotheses have been suggested to explain this abandonment. Here, we test the hypothesis that shrikes vigorously attack adult cuckoos, potentially resulting in ineffective parasitism. Adult common cuckoos resemble in appearance the Eurasian sparrowhawk (Accipiter nisus), a common predator of small passerines. One hypothesis presumes that the cuckoo has evolved this mimicry to avoid attack by small passerines when searching for their nests. Our results show that shrikes defending their nests attacked cuckoos very vigorously, more often, and more intensively than they did sparrowhawks. In the presence of a sparrowhawk dummy, parent shrikes only produced alarm calls and flew over the dummy. This suggests that cuckoo-hawk mimicry is ineffective in the case of shrikes and that they attack them much more often than they do any other presented intruder. Therefore, this activity could possibly result in the abandonment of shrikes as potential hosts for cuckoos.

Contribution of Surrounding Flowering Plants to Reduce Abundance of Aphis nerii (Hemiptera: Aphididae) on Oleanders (Nerium oleander L.)

Oleander is very frequently planted as an ornamental shrub in urban areas of the Mediterranean. Its most common pest is the aphid Aphis nerii, and heavy infestations produce aesthetic damage and disturbances to the citizens, and they are frequently sprayed with insecticides in order to reduce the population density. One alternative method is conservation biological control which is enhanced by the provisioning of alternative food, refuges, and reproduction sites. In this study, the usefulness of four flowering service plants (Lobularia maritima, Calendula officinalis, Coreopsis grandiflora, and Achillea millefolium) is evaluated for aphid infestation levels and aphid natural enemy abundances. Aphid levels were consistently lower in oleander plots surrounded by service plants. Natural enemy abundances tended to be higher in plots surrounded by service plants, but significant differences could not be found until the fourth year of the study, when more lacewings, total predators, and mummies were higher in plots surrounded by service plants. On these plots, hoverflies, ladybeetles, and lacewings were the most common predators. Paragus sp. and Hippodamia variegata were the prevalent hoverfly and ladybeetle species, respectively. The potential toxicity effect on the prevalence of natural enemy species is discussed. On service plants, significantly more hoverflies were recorded on L. maritima than on C. officinalis and C. grandiflora, and more true bugs were recorded on C. officinalis and A. millefolium than on L. maritima or C. grandiflora. Our results suggest that planting service plants (such as sweet alyssum, marigold, or yarrow) surrounding oleanders can improve conservation biological control by enhancing the abundance of aphid natural enemies and thus a reduction of the abundance of A. nerii.

Free-ranging dogs (Canis familiaris) in Lithuania: their distribution and impact on wildlife

The dog (Canis familiaris) is one of the most common predators in the world with a population of about 900 million, which continues to grow. Only 20% of the world population of dogs are considered pets. There are irresponsibly cared, free-roaming, or completely homeless individual dogs or their groups in the natural environment of Lithuania. The paper represents a study into the distribution of free-ranging dogs in the hunting areas of Lithuania and their impact on wild fauna. A telephone survey was conducted between 2019 and 2022 to find out the location of free-ranging dogs and their contact with wildlife between 2017 and 2021. Six-hundred-and-eighty users of hunting area units agreed to participate in the survey. In places where dogs were frequent, scats were collected and analysed. The conducted survey showed that in 361 hunting area units, the respondents observed free-ranging dogs at least once during the last five years, which makes 39.5% of all hunting area units in Lithuania. The dogs were observed in groups of 2–5 individuals that usually were larger than 15 kg. Free-ranging dogs interact with animals in the environment, the highest proportion of contacts (51.4%) is with roe deer (Capreolus capreolus); 35.4% of those contacts resulted in the death of roe deer. Plant residues were detected in 92% samples of scats, but roe deer residues accounted for the highest biomass consumption (49%).

Antipredator behaviors in urban settings: Ecological experimentation powered by citizen science.

Animal behaviors are often modified in urban settings due to changes in species assemblages and interactions. The ability of prey to respond to a predator is a critical behavior, but urban populations may experience altered predation pressure, food supplementation, and other human‐mediated disturbances that modify their responsiveness to predation risk and promote habituation.Citizen‐science programs generally focus on the collection and analysis of observational data (e.g., bird checklists), but there has been increasing interest in the engagement of citizen scientists for ecological experimentation.Our goal was to implement a behavioral experiment in which citizen scientists recorded antipredator behaviors in wild birds occupying urban areas. In North America, increasing populations of Accipiter hawks have colonized suburban and urban areas and regularly prey upon birds that frequent backyard bird feeders. This scenario, of an increasingly common avian predator hunting birds near human dwellings, offers a unique opportunity to characterize antipredator behaviors within urban passerines.For two winters, we engaged citizen scientists in Chicago, IL, USA to deploy a playback experiment and record antipredator behaviors in backyard birds. If backyard birds maintained their antipredator behaviors, we hypothesized that birds would decrease foraging behaviors and increase vigilance in response to a predator cue (hawk playback) but that these responses would be mediated by flock size, presence of sentinel species, body size, tree cover, and amount of surrounding urban area.Using a randomized control–treatment design, citizen scientists at 15 sites recorded behaviors from 3891 individual birds representing 22 species. Birds were more vigilant and foraged less during the playback of a hawk call, and these responses were strongest for individuals within larger flocks and weakest in larger‐bodied birds. We did not find effects of sentinel species, tree cover, or urbanization.By deploying a behavioral experiment, we found that backyard birds inhabiting urban landscapes largely maintained antipredator behaviors of increased vigilance and decreased foraging in response to predator cues. Experimentation in citizen science poses challenges (e.g., observation bias, sample size limitations, and reduced complexity in protocol design), but unlike programs focused solely on observational data, experimentation allows researchers to disentangle the complex factors underlying animal behavior and species interactions.

Were pronghorns (Antilocapra) primary prey for North American cheetahs (Miracinonyx)?

The Pronghorn ‘antelope’ (Antilocapra) of western North America have long been enigmatic because they are the second-fastest modern land mammal with no natural predators that come close to matching their speed. With the discovery of the now-extinct North American cheetah, Miracinonyx, the hypothesis was put forward that the incredible speed of pronghorns was related to being the primary prey of the fleet-footed Miracinonyx. However, there has been no direct means to test that relationship. Here, utilizing organic-molecule-rich bones from Natural Trap Cave, it is possible to test the predator-prey relationship between Antilocapra and Miracinonyx through isotopic analysis of bone collagen. Offsets in carbon and nitrogen isotopes between predator and prey are used to establish or discount predator-prey relationships between common predators found in Natural Trap Cave including wolves (Canis), cheetah-like cats (Miracinonyx), and North American lions (Panthera) with prey species like horses (Equus and Haringtonhippus), pronghorns (Antilocapra), sheep (Ovis), and bison (Bison). Results provide support the hypothesis that Miracinonyx preyed upon Antilocapra, but not exclusively. Antilocapra was also important prey for lions and wolves. Wolves appear to have fed more often on horses than lions or cheetahs.

Temporally auto-correlated predator attacks structure ecological communities.

For species primarily regulated by a common predator, the P* rule of Holt & Lawton (Holt & Lawton, 1993. Am. Nat. 142, 623–645. (doi:10.1086/285561)) predicts that the prey species that supports the highest mean predator density (P*) excludes the other prey species. This prediction is re-examined in the presence of temporal fluctuations in the vital rates of the interacting species including predator attack rates. When the fluctuations in predator attack rates are temporally uncorrelated, the P* rule still holds even when the other vital rates are temporally auto-correlated. However, when temporal auto-correlations in attack rates are positive but not too strong, the prey species can coexist due to the emergence of a positive covariance between predator density and prey vulnerability. This coexistence mechanism is similar to the storage effect for species regulated by a common resource. Negative or strongly positive auto-correlations in attack rates generate a negative covariance between predator density and prey vulnerability and a stochastic priority effect can emerge: with non-zero probability either prey species is excluded. These results highlight how temporally auto-correlated species’ interaction rates impact the structure and dynamics of ecological communities.

Evolution of toxins as a public good in phytoplankton.

Toxic phytoplankton blooms have increased in many waterbodies worldwide with well-known negative impacts on human health, fisheries and ecosystems. However, why and how phytoplankton evolved toxin production is still a puzzling question, given that the producer that pays the costs often shares the benefit with other competing algae and thus provides toxins as a 'public good' (e.g. damaging a common competitor or predator). Furthermore, blooming phytoplankton species often show a high intraspecific variation in toxicity and we lack an understanding of what drives the dynamics of coexisting toxic and non-toxic genotypes. Here, by using an individual-based two-dimensional model, we show that small-scale patchiness of phytoplankton strains caused by demography can explain toxin evolution in phytoplankton with low motility and the maintenance of genetic diversity within their blooms. This patchiness vanishes for phytoplankton with high diffusive motility, suggesting different evolutionary pathways for different phytoplankton groups. In conclusion, our study reveals that small-scale spatial heterogeneity, generated by cell division and counteracted by diffusive cell motility and turbulence, can crucially affect toxin evolution and eco-evolutionary dynamics in toxic phytoplankton species. This contributes to a better understanding of conditions favouring toxin production and the evolution of public goods in asexually reproducing organisms in general.

Incidence of invasive mealybugs, Phenacoccus solenopsis Tinsley and Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) on Gymnema sylvestre (R. Br) and its natural enemies in the semi-arid region of India

The invasive mealybugs, Phenacoccus solenopsis Tinsley and Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) are causing significant damage to Gymnema sylvestre in the semi-arid region. This study highlights the nature of the damage, severity of mealy bugs and natural enemy complex association. The severity of infestation was maximum during 23rd and 22nd Standard Meteorological Weeks (SMW) (3.67 and 3.66) of 2019 and 2020, respectively. The pooled data of both the years revealed that temperature has a significant positive correlation and rainfall has a negative correlation towards the severity of the pest incidence with respective r-values of 0.678** and −0.05. A total of 19 different natural enemies identified belong to 7 families of 4 insect orders. Cheilomenes sexmaculata (Fabricius) was the most common predator and among the parasitoids, three species of primary parasitoids viz., Aenasius arizonensis (Girault) and Pseudleptomastix mexicana Noyes & Schauff (Hymenoptera: Encyrtidae) were more abundant. Besides, six species are hyperparasitoids viz., Aprostocetus sp, Chartocerus sp., Cheiloneurus sp., Homalotylus turkmenicus Myartseva, Marietta leopardina Motschulsky and Prochiloneurus sp. were recorded from primary parasitoids.

Do Red-cockaded Woodpecker (Dryobates borealis) cavity locations provide olfactory concealment from predators?

Nest site selection is crucial for survival and fecundity of birds. Predators find nests using visual, aural, thermal, and olfactory cues, yet few studies have evaluated olfactory concealment of nests. Rat snakes (Pantherophis spp.) are common nest predators that use ground-level olfactory cues to detect nest locations. In Arkansas, USA, we evaluated if cavity locations of the Red-cockaded Woodpecker (Dryobates borealis, RCW), a species that experiences nest predation by rat snakes, were associated with airflow conditions known to provide olfactory concealment for other bird species. We used a 3-dimensional sonic anemometer to measure ground-level air velocity, turbulence, and turbulence intensity at cavity trees and unused trees, and at cavity and opposite orientations on trees. For all airflow variables, we found no differences between used and unused trees and orientations. Other factors such as landscape-scale vegetation cover, forest stand structure, and tree characteristics may be more important for providing visual concealment or optimal foraging conditions. However, it remains possible that such factors also convey olfactory concealment. For example, savannah-like forests preferred by RCWs may have greater air turbulence than closed forests. Further research on RCWs and other bird species to address additional aspects of olfactory concealment, and relationships between different dimensions of concealment (e.g., between visual and olfactory concealment), would give insight into how habitat management could provide multiple benefits to birds.

Variation in abundance and life-history traits of two congeneric Arctic wolf spider species, Pardosa hyperborea and Pardosa furcifera, along local environmental gradients

The Arctic tundra is characterised by harsh conditions and environmental gradients are especially pronounced. Variation in functional traits along such gradients provide insights into the drivers of species abundance and distribution and are particularly valuable in this region currently experiencing strong climate warming. Over three consecutive years, we analysed the interacting effect of two environmental factors, habitat and elevation, on the abundance, body size, and clutch size in two common Low-Arctic invertebrate predators (Lycosidae, Araneae), Pardosa furcifera (Thorell 1875) and Pardosa hyperborea (Thorell 1872). Using generalised linear models, we firstly showed a habitat partitioning between P. furcifera, which dominated wet habitats, like fens, and P. hyperborea, which was more associated with drier habitats, like shrubs. Secondly, we found smaller body sizes at high elevation in P. hyperborea, a species that has a southern distribution in Greenland, and we identified season length as a major driver of the development in this species. In P. furcifera, a species likely more cold adapted, we found no body size difference between elevations, suggesting that local conditions (e.g. prey availability or snowmelt timing) are more important in explaining body size variations. Finally, body size and clutch size were strongly correlated in both species, but clutch size was not affected by habitat or elevation. We argue that fecundity is likely influenced by trade-offs and that considering additional complementary trait measurements would allow for a better understanding of the mechanisms underlying patterns in species life-history traits along environmental gradients.

Predation‐mediated edge effects reduce survival of wader nests at a wet grassland‐forest edge

AbstractEdge effects occur when the matrix has adverse impacts on the patches of remnant habitat. A widely explored example of this is the hypothesis of a higher predation pressure on bird nests closer to the habitat edge. In parallel with the recent loss of open habitats through afforestation as a climate change mitigation measure, an interest in the impact of forest on species dependent on open habitats has re‐emerged. We follow wader nest survival to study the issue of an edge effect in a system of wet grasslands fragmented by forests in a region where it has not been tested before, focussing mainly on northern lapwing (Vanellus vanellus), common ringed plover (Charadrius hiaticula), common redshank (Tringa totanus) and southern dunlin (Calidris alpina schinzii). To record nest survival, we monitored 753 nests of 10 wader species on coastal grasslands in Estonia for 3 consecutive years. A subset (n = 85) of these nests was equipped with camera traps to record nest predation events and predator association with forest edge. The distance to nearest trees and forest and a forest cover within a 1‐km buffer around each nest was measured. We recorded extremely low daily nest survival rates (0.903–0.922 for different species), with most nests lost to predation. We showed that nest survival is lower closer to the forest edge and negatively affected by the proportion of forest within a 1‐km buffer around each nest. Based on camera trap recordings, we suggest that the edge effect is caused by elevated nest predation rates by the most common predator, the red fox (Vulpes vulpes), closer to the forest edge. Future afforestation plans of open habitats need to acknowledge that the resulting fragmentation has a negative impact on nest survival of ground‐breeding birds. On the other hand, our results imply that restoration efforts aimed at removal of most damaging forest plantations could benefit breeding waders.

Complete genome analysis of a novel picorna-like virus from a ladybird beetle (Cheilomenes sexmaculata).

The ladybird beetle Cheilomenes sexmaculata (family Coccinellidae, order Coleoptera) is a common insect predator of agricultural pests. In this study, the full genome sequence of a novel picorna-like virus, tentatively named "Cheilomenes sexmaculata picorna-like virus 1" (CSPLV1), was identified in C. sexmaculata. The full-length sequence of CSPLV1 is 11,384 nucleotides (nt) in length (excluding the polyA tail), with one predicted open reading frame (ORF) encoding a polyprotein of 3727 amino acids, a 13-nt 5' untranslated region (UTR), and a 187-nt 3' UTR. The ORF of CSPLV1 consists of four distinct domains, including an RNA virus helicase domain (nt 3029-3319), a peptidase domain (nt 5555-6121), an RNA-dependent RNA polymerase domain (nt 7154-8101), and a picorna-like coat protein domain (nt 8606-9283). Phylogenetic analysis based on the conserved RdRP sequence showed that CSPLV1, together with Wuhan house centipede virus 3, Hypera postica associated virus 1, and Diabrotica undecimpunctata virus 1, forms an unclassified group that is closely related to members of the family Solinviviridae. To the best of our knowledge, CSPLV1 is the first picorna-like virus discovered in C. sexmaculata.

Pattern formation and coarsening dynamics in apparent competition models

Apparent competition is an indirect interaction between species that share natural resources without any mutual aggression but negatively affect each other if there is a common enemy. The negative results of the apparent competition are reflected in the species spatial segregation, which impacts the dynamics of their populations. Performing a series of stochastic simulations, we study a model where organisms of two prey species do not compete for space but share a common predator. Our outcomes elucidate the central role played by the predator in the pattern formation and coarsening dynamics in apparent competition models. Investigating the effects of predator mortality on the persistence of the species, we find a crossover between a curvature driven scaling regime and a coexistence scenario. For low predator mortality, spatial domains mainly inhabited by one type of prey arise, surrounded by interfaces that mostly contain predators. We demonstrate that the dynamics of the interface network are curvature driven whose coarsening follows a scaling law common to other nonlinear systems. The effects of the apparent competition decrease for high predator mortality, allowing organisms of two prey species to share a more significant fraction of lattice. Finally, our results reveal that predation capacity in single-prey domains influences the scaling power law that characterises the coarsening dynamics. Our findings may be helpful to biologists to understand the pattern formation and dynamics of biodiversity in systems with apparent competition.

A multi-isotope approach to evaluate the potential of great cormorant eggs for contaminant monitoring

Contaminant monitoring in biota is important for determining environmental status and to detect or prioritize action on hazardous substances. Predators higher up a food chain are often used for monitoring of contaminants that bioaccumulate. However, it is not always possible to find higher predators that are both abundant and have a wide distribution for national or international contaminant monitoring. Great cormorants (Phalocrocorax carbo) are a widespread and increasingly common top predator of fish in fresh, brackish and salt water. We evaluate the suitability of great cormorant eggs as a matrix for contaminant monitoring by using stable isotopes of carbon, nitrogen and sulfur. Despite the fact that cormorants are migratory, egg isotope values showed a significant separation between five breeding colonies in Sweden (1 fresh water lake, 3 Baltic sites and 1 marine site). This high degree of separation indicates that eggs are primarily produced using local resources (not stored body resources) and that contaminants (mercury concentrations in this study) measured in eggs likely reflect levels in fish prey caught close to the breeding area. Compound specific stable isotope analysis was used to estimate cormorant trophic position (TP) and concentrations of mercury in eggs were positively related to TP. The results show that a multi-isotope approach, combined with good ecological diet knowledge allow for meaningful and comparative interpretation of mercury concentrations in biota and that great cormorant eggs appear a suitable matrix to measure locally derived and maternally transferred contaminants.

The effect of squash domestication on a belowground tritrophic interaction.

The domestication of plants has commonly resulted in the loss of plant defense metabolites, with important consequences for the plants' interactions with herbivores and their natural enemies. Squash domestication started 10'000years ago and has led to the loss of cucurbitacins, which are highly toxic triterpenes. The banded cucumber beetle (Diabrotica balteata), a generalist herbivore, is adapted to feed on plants from the Cucurbitaceae and is known to sequester cucurbitacins, supposedly for its own defense. However, the evidence for this is inconclusive. In this study we tested the impact of squash domestication on the chemical protection of D. balteata larvae against a predatory rove beetle (Dalotia coriaria). We found that cucurbitacins do not defend the larvae against this common soil dwelling predator. In fact, D. balteata larvae were less attacked when they fed on cucurbitacin-free roots of domesticated varieties compared to high-cucurbitacin roots of wild plants. This study appears to be the first to look at the consequences of plant domestication on belowground tritrophic interactions. Our results challenge the generalized assumption that sequestered cucurbitacins protect this herbivore against natural enemies, and instead reveals an opposite effect that may be due to a tradeoff between coping with cucurbitacins and avoiding predation.

Zelus renardii Roaming in Southern Italy.

Simple SummaryThe leafhopper assassin bug Zelus renardii (Hemiptera: Reduviidae) first entered Europe in 2012 and has since acclimatised. Z. renardii is now a common insect predator in agroecosystems and urban and peri-urban areas. We performed a metadata analysis of 165 years of Z. renardii literature. Moreover, we provide laboratory tests of Z. renardii predation. The latter indicates Z. renardii interplay with relevant insect targets, such as Philaenus spumarius, Neophilaenus campestris, Bactrocera oleae, Kermes vermilio, Nidularia pulvinata, Harmonia axyridis, Apis mellifera, Aleurocanthus spiniferus, Aleurothrixus floccosus, Macrohomotoma gladiata, Drosophila suzukii, Drosophila melanogaster, Megaselia scalaris, Pseudococcidae, Miridae, and Issidae. Furthermore, predation on Aphrophoridae and other olive pests brands Z. renardii as a good mass-rearing candidate for inundative biocontrol programs of Xylella fastidiosa pauca ST53 infections and could also reduce damage caused by other olive pests. Overall, this reduviid is harmless to humans and beneficial insects.This study collects data from the literature and updates our Zelus renardii Kolenati, 1856 (Leafhopper Assassin Bug, LAB) prey knowledge. The literature consists of ca. 170 entries encompassing the years 1856 to 2021. This reduviid originated in the Nearctic region, but has entered and acclimatised in many Mediterranean countries. Our quantitative predation experiments—in the laboratory on caged plants plus field or environmental observations—confirm that LAB prefers a selected array of prey. Laboratory predation tests on living targets (Hemiptera, Coleoptera, Diptera, and Hymenoptera) agree with the literature. Zelus renardii prefers comparatively large, highly mobile, and readily available prey. LAB preferences on available hemipterans targets suggest that Zelus renardii is a good inundative biocontrol agent for Xylella fastidiosa pauca ST53 infections. LAB also prey on other important olive pests, such as Bactrocera oleae. Therefore, Zelus renardii is a major integrated pest management (IPM) component to limit Xylella fastidiosa pandemics and other pest invasions.

Rickettsiae among mustelids - new data from south-west Poland.

Information on the prevalence on Rickettsia spp. in free-ranging mustelids and their specific ectoparasites is scarce. However, stone martens (Martes foina), pine martens (Martes martes) and European badgers (Meles meles) are common predators in many regions of Poland. In the present study we used tissue fragments to determine Rickettsia prevalence in these carnivores by molecular biology techniques. In addition, we included a data on several species of invertebrates that commonly feed on badgers.

Diversity of mite fauna and varietal screening against yellow mite, Polyphagotarsonemus latus (Bank) in chilli under Gangetic basin of West Bengal, India

The present study was undertaken to explore the diversity of predatory mites as well as their associated phytophagous prey mites for development of better and ecologically sound mite pest management strategy and to select suitable cultivars from an indigenous gene pool against yellow mite. Eight chilli cultivars were screened and incidence pattern of yellow mite was observed during the period of investigation. Results revealed that none of the cultivars were resistant against the yellow mite but BCCH-SL-4 was found least susceptible to yellow mite. Altogether 12 species of predatory mites belonging to 5 families were encountered in chilli crop. The predatory mite families included Phytoseiidae, Cunaxidae, Bdellidae, Tydeidae, and Ascidae represented by the genera Amblyseius, Typhlodromips, Euseius, Neoseiulus, Paraphytoseius, Scapulaseius, Cunaxa, Bdellodes and Tydeus. The associated phytophagous mite families were recorded like Tetranychidae, Tenuipalpidae and Tarsonemidae represented by the genera Tetranychus, Schizotetranychus, Eutetranychus, Brevipalpus and Polyphagotarsonemus. Mite in the family Phytoseiidae was found to be the most common predators and Typhlodromips syzygii was observed as predominant predory mite species followed by Amblyseius largoensis.

Nest remains are insufficient to identify predators of waterfowl nests

Context Nest predation is a leading cause of nest failure for most ground-nesting birds. Methods that allow for accurate classification of fate and identification of predators are important for understanding productivity and conservation strategies. Past studies have used a visual inspection of nest remains to determine nest fate and predict predator identity. Most formal assessments of these methods have addressed small-bodied birds nesting in trees or shrubs, and have revealed that use of evidence at nests can be relatively accurate for determining nest fate but may lead to incorrect conclusions regarding predator identity. However, few have tested the latter hypothesis for larger ground-nesting birds with precocial young. Aim We aimed to evaluate a classification system developed for determining nest fate and identifying predators of waterfowl nests, at both the scale of individual nests and across the study area. Methods From 2016 to 2020, we located 989 blue-winged teal (Spatula discors), mallard (Anas platyrhynchos) and gadwall (Mareca strepera) nests in central North Dakota. We placed cameras at a subset of 249 nests and recorded evidence of nest remains at depredated nests. Key results The most common predators were American badgers (Taxidea taxus), followed by striped skunks (Mephitis mephitis), raccoons (Procyon lotor) and red foxes (Vulpes vulpes). Using evidence of nest remains, we determined nest fates with high accuracy (98.0%). However, evidence of nest remains was only sufficient for identifying predators at 50% of nests, and the classification system was correct only 69.7% of the time. The predicted proportion of predators across the study area differed between the classification system and our video evidence as well. Conclusions The accuracy of predator identifications based upon the classification system that we evaluated was not supported at any scale. Implications Our results suggest that evidence of nest remains can be used to determine nest fate for large-bodied precocial, ground-nesting birds, but accurate identification of nest predators will require alternative methods such as nest cameras.