Rodent Predation Research Articles

Cascading carrion: Opportunistic predation at deer gut piles

Carrion is increasingly recognized as an important part of food web ecology that impacts multiple trophic levels and creates an arena for multiple species interactions. The pulsed nature of hunter-derived carrion, in the form of gut piles, is a form of carrion that has been overlooked in the study of food webs and scavenger interaction. The Offal Wildlife Watching project aims to better understand scavenger species that benefit from offal and how they interact with each other and this resource. Through citizen science efforts by hunters and Zooniverse volunteers, we have collected and analyzed over 230,000 images of scavengers at white-tailed deer gut piles. At some gut piles, we have observed barred owls and bobcats both scavenging at hunter provided gut piles and preying on rodents that were also attracted to the gut pile. This interaction, made possible by a food subsidy that is historically novel in time and space, may have implications for rodent populations, predator survival and fecundity, and the activity patterns of both. Continued research and investigation will shed light on the impacts of cascading carrion on species interaction.

Macro-parasites and micro-parasites co-exist in rodent communities but are associated with different community-level parameters

Wildlife species are often heavily parasitized by multiple infections simultaneously. Yet research on sylvatic transmission cycles, tend to focus on host interactions with a single parasite and neglects the influence of co-infections by other pathogens and parasites. Co-infections between macro-parasites and micro-parasites can alter mechanisms that regulate pathogenesis and are important for understanding disease emergence and dynamics. Wildlife rodent hosts in the Lyme disease system are infected with macro-parasites (i.e., ticks and helminths) and micro-parasites (i.e., Borrelia spp.), however, there has not been a study that investigates the interaction of all three parasites (i.e., I. pacificus, Borrelia spp., and helminths) and how these co-infections impact prevalence of micro-parasites. We live-trapped rodents in ten sites in northern California to collect feces, blood, ear tissue, and attached ticks. These samples were used to test for infection status of Borrelia species (i.e., micro-parasite), and describe the burden of ticks and helminths (i.e., macro-parasites). We found that some rodent hosts were co-infected with all three parasites, however, the burden or presence of concurrent macro-parasites were not associated with Borrelia infections. For macro-parasites, we found that tick burdens were positively associated with rodent Shannon diversity while negatively associated with predator diversity, whereas helminth burdens were not significantly associated with any host community metric. Ticks and tick-borne pathogens are associated with rodent host diversity, predator diversity, and abiotic factors. However, it is still unknown what factors helminths are associated with on the community level. Understanding the mechanisms that influence co-infections of multiple types of parasites within and across hosts is an increasingly critical component of characterizing zoonotic disease transmission and maintenance.

Silent killers? The widespread exposure of predatory nocturnal birds to anticoagulant rodenticides

Anticoagulant rodenticides (ARs) influence predator populations and threaten the stability of ecosystems. Understanding the prevalence and impact of rodenticides in predators is crucial to inform conservation planning and policy. We collected dead birds of four nocturnal predatory species across differing landscapes: forests, agricultural, urban. Liver samples were analysed for eight ARs: three First Generation ARs (FGARs) and five SGARs (Second Generation ARs). We investigated interspecific differences in liver concentrations and whether landscape composition influenced this. FGARs were rarely detected, except pindone at low concentrations in powerful owls Ninox strenua. SGARs, however, were detected in every species and 92 % of birds analysed. Concentrations of SGARs were at levels where potential toxicological or lethal impacts would have occurred in 33 % of powerful owls, 68 % of tawny frogmouths Podargus strigoides, 42 % of southern boobooks N. bookbook and 80 % of barn owls Tyto javanica. When multiple SGARs were detected, the likelihood of potentially lethal concentrations of rodenticides increased. There was no association between landscape composition and SGAR exposure, or the presence of multiple SGARs, suggesting rodenticide poisoning is ubiquitous across all landscapes sampled. This widespread human-driven contamination in wildlife is a major threat to wildlife health. Given the high prevalence and concentrations of SGARs in these birds across all landscape types, we support the formal consideration of SGARs as a threatening process. Furthermore, given species that do not primarily eat rodents (tawny frogmouths, powerful owls) have comparable liver rodenticide concentrations to rodent predators (southern boobook, eastern barn owl), it appears there is broader contamination of the food-web than anticipated. We provide evidence that SGARs have the potential to pose a threat to the survival of avian predator populations. Given the functional importance of predators in ecosystems, combined with the animal welfare impacts of these chemicals, we propose governments should regulate the use of SGARs.

Reducing seed predation by introduced rodents helps, but is insufficient, to prevent long-term decline of common forest trees

Understanding how novel biotic interactions can affect the persistence of plant and animal populations is of critical conservation concern. Rodents have been introduced to most oceanic islands and predate a wide range of seeds. However, little research has evaluated their effects on the long-term viability of plant populations. We assess the effects of seed predation by introduced rodents on the demography of three long-lived, common native trees in a Hawaiian forest. Using a 17-year demographic dataset, we assess if populations are viable under standard forest conservation practices; then we explore the potential effects of reducing seed predation by non-native organisms, reducing non-native understory cover, or reducing both, on population growth. Post-dispersal seed removal ranged from 40 to 98 % and increased as a function of understory cover. Survival was low for seedlings due to competition from non-native understory plants. Sixty-two percent of Pysdrax odorata seeds suffered pre-dispersal predation by an introduced moth and 72 % of Nestegis sandwicensis seeds were prematurely aborted. Integral projection models show that λ values under standard conservation were <1, indicating population decline. Reducing seed predation by introduced rodents had a strong positive effect on λ for Diospyros sandwicensis, but the effect was much smaller for the other two species. Seed predation by introduced rodents can drive slow population decline of common native trees even in areas actively managed for conservation. Further, reducing rodent predation alone is likely insufficient to ensure long-term persistence due to additional bottlenecks in viable seed production. More attention to common tree species on oceanic islands is critical.

Response of chestnut hybrid seedlings to forest management strategies in an Appalachian cove forest ecosystem

American chestnut (Castanea dentata (Marsh) Borkh.), once a co-dominant canopy species in eastern U.S. forests, has been functionally extinct for almost a century. Hybrid American-Chinese chestnuts, with the potential to be blight-resistant, present an opportunity to study its functional niche. The objective of this research was to identify silvicultural strategies related to light, herbivory, and competition for increasing the success of hybrid chestnut (BC3F3 generation) plantings in an Appalachian cove forest ecosystem in West Virginia (WV). Large and small circular canopy gaps were created to manipulate light with the prediction that seedlings would perform best in larger gaps. Within these gaps, landscape fabric was added to half of the seedlings to decrease vegetative competition and 30.5 cm tall tree shelters were placed around half of the seedlings to help mitigate rodent predation. After five years, results show an interaction between landscape fabric and gap size whereby landscape fabric had a positive effect on seedling height in large gaps but not in small gaps (p < 0.05). Survival was dependent on interactions between treatments with the highest seedling survival (80%) in small gaps with tree shelters and landscape fabric. Differences between treatments were less pronounced in large gaps where survival was much lower (45%). In conclusion, seedlings are likely to have the greatest long-term survival if they are planted in smaller gaps protected from vegetative competition and rodent predation.

First published record of rodent predation by guira cuckoo in Brazil: notes about vertebrate predation

Guira cuckoo (Guira guira) is a communal breeder bird species displaying a diversified diet. In this study, we report the first published predation event of a rodent by Guira cuckoo in Brazil. We searched for vertebrate predation by this bird species in Brazilian domains in the following databases: Google Scholar, SciELO, Scopus and Web of Science. We recorded the rodent predation event in a landscape composed of pasture and gallery forest in Campo Grande municipality, Mato Grosso do Sul, central-west Brazil. The predated rodent is a vesper mouse, Calomys sp. We found 19 vertebrate species predated by the Guira cuckoo, distributed in all Brazilian domains, within the orders: Anura (5 species), Passeriformes (1), Squamata (12), and Rodentia (1 - present study). Our result contributes to the natural history of the Guira cuckoo, and highlights that this cuckoo bird displays a generalist diet, feeding on a diversity of vertebrate species.

Weasel exposure to the anticoagulant rodenticide bromadiolone in agrarian landscapes of southwestern Europe.

Bromadiolone is an anticoagulant rodenticide (AR) commonly used as a plant protection product (PPP) against rodent pests in agricultural lands. ARs can be transferred trophically to predators/scavengers when they consume intoxicated live or dead rodents. ARs exposure in weasels Mustela nivalis, small mustelids specialized on rodent predation, is poorly known in southern Europe. Moreover, in this species there is no information on bioaccumulation of AR diastereomers e.g., cis- and trans-bromadiolone. Trans-bromadiolone is more persistent in the rodent liver and thus, is expected to have a greater probability of trophic transfer to predators. Here, we report on bromadiolone occurrence, total concentrations and diastereomers proportions (trans- and cis-bromadiolone) in weasels from Castilla y León (north-western Spain) collected in 2010-2017, where bromadiolone was irregularly applied to control outbreaks of common voles Microtus arvalis mainly with cereal grain bait distributed by the regional government. We also tested variables possibly associated with bromadiolone occurrence and concentration, such as individual features (e.g., sex), spatio-temporal variables (e.g., year), and exposure risk (e.g., vole outbreaks). Overall bromadiolone occurrence in weasels was 22% (n = 32, arithmetic mean of concentration of bromadiolone positives = 0.072 mg/kg). An individual showed signs of bromadiolone intoxication (i.e., evidence of macroscopic hemorrhages or hyperaemia and hepatic bromadiolone concentration > 0.1 mg/kg). All the exposed weasels (n = 7) showed only trans-bromadiolone diastereomer in liver, whilst a single analyzed bait from those applied in Castilla y León contained trans- and cis-bromadiolone at 65/35%. Bromadiolone occurrence and concentration in weasels varied yearly. Occurrence was higher in 2012 (100% of weasels), when bromadiolone was widely distributed, compared to 2016-2017 (2016: 20%; 2017: 8.33%) when bromadiolone was exceptionally permitted. The highest concentrations happened in 2014 and 2017, both years with vole outbreaks. Our findings indicate that specialist rodent predators could be exposed to bromadiolone in areas and periods with bromadiolone treatments against vole outbreaks.

The influence of sugarcane pre‐harvest fire on hantavirus prevalence in Neotropical small mammals

AbstractThe use of pre‐harvest fire in sugarcane fields surprisingly results in an increase in the abundance of Neotropical Sigmodontinae rodents, which might carry hantavirus. By contrast, fire suspension induces a decline in rodents in the first 5 years. The present study aimed to evaluate the effect of sugarcane harvest regimes on hantavirus prevalence in wild rodents. Field collections were carried out on a sugarcane production area in Northeast São Paulo, which is responsible for 30% of the ethanol production in Brazil. A few years after pre‐harvest fire suspension, a high prevalence of hantavirus was found in small rodents at lower population density, but apparently higher population growth rate. Differences in life cycle between the rodents and their predators may explain such density patterns, as small rodents can breed twice or even three times each year, whereas their predators usually breed only once a year. Similarly, the temporal dynamics of the predator–prey relationship suggests that hantavirus prevalence is related to small rodent's population growth and not density. OnlyAkodon montensis,Calomys tener, andNecromys lasiuruscontained immunoglobulin G antibodies against the recombinant nucleoprotein ofAraraquara orthohantavirus, a genotype ofAndes orthohantavirus, with no interspecific variation in seroprevalence among these species. However, males presented higher prevalence rate than females, possibly due to a male‐biased dispersal pattern and a higher frequency of antagonistic interactions. Governance measures to mitigate the role of small wild rodents on the emergence of hantavirus in agricultural landscapes dominated by sugarcane plantations should include the use of wildlife‐friendly management techniques (e.g., to mitigate the mortality of the predators of small rodents), human capacity building concerning wildlife‐related conflicts, and multifunctionality of agricultural landscapes. Future studies should prioritize the possible relationship between microhabitat structure and hantavirus prevalence in small rodents in agricultural landscapes dominated by sugarcane fields.

Enantiomer fraction evaluation of the four stereoisomers of second-generation anticoagulant rodenticides in biological matrices with polysaccharide-based chiral selectors and liquid chromatography tandem mass spectrometry

Numerous cases of wildlife exposure to five second-generation anticoagulant rodenticides have been reported worldwide, and residues of these chiral pesticides in biological matrices are still quantified by achiral liquid chromatography methods. However, they are a mixture of cis- and trans-diastereomers, thus a mixture of four stereoisomers. Their persistence must be evaluated in a differentiated way in the food chain of concerned predator species in order to reduce the environmental impact.This article presents an evaluation of the chiral selectivity of five polysaccharide-based chiral selectors for the four stereoisomers of bromadiolone, difenacoum, brodifacoum, flocoumafen and difethialone. Different chromatographic parameters, influencing the chiral separation, such as organic modifier (acetonitrile, methanol), percentage of formic acid and water content in the mobile phase are systematically tested for all columns. It was shown that little amount of water added to the acetonitrile mobile phase may influence the retention behaviors between reversed phase and HILIC-like modes, and consequently the enantiomer elution order of the four stereoisomers. On the contrary, reversed phase is always the observed mode for the methanol water mobile phase. A suitable combination of all these parameters is presented for each second-generation anticoagulant rodenticide with a description of the enantioresolution, the enantiomer elution order and the retention times of the respective stereoisomers. A method is validated for all stereoisomers of each second-generation anticoagulant rodenticide with chicken liver and according to an official bioanalytical guideline. As an example, the enantiomer fraction is evaluated in the liver of a raptor species (rodent predator) exposed to bromadiolone and difenacoum. The results showed that only one enantiomer of trans-bromadiolone and one enantiomer of cis-difenacoum is present in hepatic residues, although all four stereoisomers are present in bromadiolone and difenacoum rodenticide baits.

Flexibility and rigidity in hunting behaviour in rodents: is there room for cognition?

Predatory hunting is a complex species-typical behaviour involving different skills, some of which may include learning. This research aims to distinguish between rigid and flexible parts in live-insect hunting behaviour in nine herbivorous and granivorous rodent species, and to find out whether there is room for cognition in this activity. In laboratory experiments, all species studied manifest skilful attacks towards insects in a manner that is typical for specialised predators chasing a fleeing prey. Voles demonstrate a "core" and somewhat primitive scheme of a hunting pattern: approaching a potential victim, biting it, and then seizing and handling. Hamsters display the tendency to start their attacks by actions with paws, but they can achieve success only using teeth as well. Gerbils can successfully use both paws and teeth to start the attack, which brings their hunting behaviour closer to that of specialised rodent predators. We revealed variability in the display of hunting in different species, methods of seizing the prey, and the number of attempts to attack an insect before catching it. We found specific flexible fragments within the "bite-grasp-handle" bouts that can be precursors for adaptive phenotypic variations and include some cognitive attributes. We hypothesise that the divergence and specialisation of predatory behaviour in rodents can be based on the natural fragmentation of the original hunting patterns, that is, on the loss or recombination of particular behavioural elements. We consider a possible link between the fragmentation of hunting behaviour and social learning in different classes of animals and conjecture an intriguing correlation between predatory activity, cognitive skills and personal traits in rodents.

Native seed dispersal by rodents is negatively influenced by an invasive shrub

Refuge–mediated apparent competition is the mechanism by which invasive plants increase pressure on native plants by providing refuge for generalist consumers. In the UK, the invasive Rhododendron ponticum does not provide food for generalist seed consumers like rodents, but evergreen canopy provides refuge from rodent predators, and predation and pilferage risk are key factors affecting rodent foraging and caching behaviour. Here we used a seed removal/ seed fate experiment to understand how invasion by an evergreen shrub can alter seed dispersal, seed fate and early recruitment of native trees. We used seeds of four species, small and wind–dispersed (sycamore maple Acer pseudoplatanus and European ash Fraxinus excelsior) and large and animal–dispersed (pedunculate oak Quercus robur and common hazel Corylus avellana), and monitored seed predation and caching in open woodland, edge habitats, and under Rhododendron. In the open woodland, wind–dispersed seeds had a higher probability of being eaten in situ than cached seeds, while the opposite occurred with animal–dispersed seeds. The latter were removed from the open woodland and edge habitats and cached under Rhododendron. This pattern was expected if predation risk was the main factor influencing the decision to eat or to cach a seed. Enhanced dispersal towards Rhododendron cover did not increase the prospects for seed survival, as density of hazel and oak saplings under its cover was close to zero as compared to open woodland, possibly due to increased cache pilferage or low seedling survival under dense shade, or both. Enhanced seed predation of ash and sycamore seeds close to Rhododendron cover also decreased recruitment of these trees. Rhododendron patches biased rodent foraging behaviour towards the negative (net predation) side of the conditional rodent / tree interaction. This effect will potentially impact native woodland regeneration and further facilitate Rhododendron spread due to refuge–mediated apparent competition.

Diet and occurrences of the letter-winged kite in a predation refuge.

Nomadism is an advantageous life history strategy for specialised predators because it enables the predator to respond rapidly to changes in prey populations. The letter-winged kite (Elanus scriptus) is a nomadic nocturnal bird of prey endemic to arid and semi-arid zones of Australia. Letter-winged kites prey almost exclusively on nocturnal rodents and are often associated with rodent irruptions, but little is known about the ecology of letter-winged kites inside their core range. The Strzelecki Desert contains a known dingo-mediated predation refuge for native rodents. In this manuscript, we compare kite sightings, predator activity, and small mammal populations across survey sites in the Strzelecki Desert where dingoes were common and where dingoes were rare and use publicly available data from the Atlas of Living Australia (ALA) to assess trends in the occurrence of kites in the region. Ninety-five percent of ALA observations occurred in areas where dingoes were common. Similarly, all our observations of kites occurred where dingoes were common and during an extended population irruption of Notomys fuscus. Notomys fuscus was the most frequent item in the letter-winged kite diet at our study sites. We suggest that there is significant evidence that these sites in the Strzelecki Desert form part of the core range for the letter-winged kite whose use of this area is facilitated by a predation refuge for rodents mediated by the dingo. We conclude that predation refuges mediated by dingoes could be a factor driving the distributions of letter-winged kites and other predators of rodents, particularly nomadic predators.

Conservation Letter: Raptors and Anticoagulant Rodenticides

Conservation Letter: Raptors and Anticoagulant Rodenticides

Size-related seed use by rodents on early recruitment of Quercus serrata in a subtropical island forest

Rodents are ubiquitous seed predators in nature and their size-related seed choice plays an important role in the plant’s community structure. However, to understand how size-related seed predation by rodents affects plant recruitment, it is fundamental to predict seed and seedling response to rodent predation. We assessed the interactive effects between seed size and rodent exclusion on seed germination and early seedling survival of Quercus serrata in 10 subtropical forested islands in Thousand Island Lake, China. We found that rodent exclusion significantly improved the proportion of seed germination but not for early seedling survival. The proportion of seed germination in rodent-accessed plots was lower than rodent-exclosure plots and such reduction was strengthened by seed size. The proportion of early seedling survival was similar in both treatments and both increased with seed size. Our study found a significant size-related seed choice by rodents at the seed germination stage and showed that seeds would experience conflicting selective pressures across life stages in the early recruitment. Our findings highlight that size-dependent seed use by rodents is a key biotic factor to limit the oak early recruitment.

Unexpected involvement of a second rodent species makes impacts of introduced rats more difficult to detect

Rodent predators are implicated in declines of seabird populations, and removing introduced rats, often, but not always, results in the expected conservation gains. Here we investigated the relationship between small mammal (Norway rat, wood mouse and pygmy shrew) abundance and Manx shearwater breeding success on the island of Rum, Scotland, and tested whether localised rodenticide treatments (to control introduced Norway rats) increased Manx shearwater breeding success. We found that Manx shearwater breeding success was negatively correlated with late summer indices of abundance for rats and mice, but not shrews. On its own, rat activity was a poor predictor of Manx shearwater breeding success. Rat activity increased during the shearwater breeding season in untreated areas but was supressed in areas treated with rodenticides. Levels of mouse (and shrew) activity increased in areas treated with rodenticides (likely in response to lower levels of rat activity) and Manx shearwater breeding success was unchanged in treated areas (p < 0.1). The results suggest that, unexpectedly, negative effects from wood mice can substitute those of Norway rats and that both species contributed to negative impacts on Manx shearwaters. Impacts were intermittent however, and further research is needed to characterise rodent population trends and assess the long-term risks to this seabird colony. The results have implications for conservation practitioners planning rat control programmes on islands where multiple rodent species are present.

A non‐native earthworm shifts seed predation dynamics of a native weed

Abstract Introduced seed dispersers can shift seed predation dynamics in native species, impacting native plant establishment and spread. We studied the effect of the non‐native earthworm, Lumbricus terrestris, on seed loss dynamics in the large‐seeded native annual, Ambrosia trifida (giant ragweed), an expanding agricultural weed whose seeds are heavily predated by mice. Lumbricus terrestris may protect seeds against rodent predation by caching them in its burrows from which seedlings can emerge unharmed; however, little is known about the ability of earthworms to compete with rodents for seeds. We investigated this interaction and how environmental factors affected the competitive outcome. In a 2‐year field study, we analysed relative rates of seed removal by earthworms and mice for seeds dispersed at various times in habitats that varied in vegetative cover. Species‐specific responses to environmental conditions drove variation in the share of seeds taken by earthworms versus mice, with earthworms gaining relatively more seeds under warmer, wetter conditions and in low plant cover habitats, and mice obtaining more seeds under colder, drier conditions and in high cover habitats. Environmental factors also determined which competitor accessed seeds first, and this conferred a competitive advantage that was compounded over time. Earthworms cached some seeds under all experimental conditions, suggesting that L. terrestris can act mutualistically with giant ragweed in diverse environments. Synthesis and applications. Our results support the hypothesis that the non‐native earthworm Lumbricus terrestris behaves as a seed dispersal mutualist for the native annual giant ragweed by caching its seeds in its burrows, thereby reducing their availability to rodent seed predators. The data also support the view that interactions among the environment and competing seed predators determine the fate of seed pools in response to species‐specific environmental preferences. In crop fields where L. terrestris is abundant, additional efforts to prevent giant ragweed seed return may be warranted due to the likelihood that earthworms will increase giant ragweed soil seed pools. Lumbricus terrestris is expanding its range throughout temperate regions and may similarly affect secondary seed dispersal and seed predation dynamics of large‐seeded species in other plant communities.

Effects of mast seeding and insect infestation on predation and dispersal of Castanea mollissima nuts by rodents in the Qinling Mountains of China

Seed predation and dispersal by rodents plays an important role in woodland regeneration. To understand the impact of insect-infestation under different food abundance conditions on rodent predation and dispersal preferences, it is necessary to determine whether rodents have the ability to distinguish between infested and non-infested seeds and whether feeding strategies are affected by food abundance. Here, we compared the predation and dispersal fates of infested and non-infested nuts of Castanea mollissima in mast and non-mast years in a subtropical forest in the Qinling Mountains, central China. We found that rodents could discriminate between infested and non-infested nuts of C. mollissima. Harvest rates of non-infested nuts were relatively faster than those of infested nuts, and rodents preferred to consume infested nuts (typically in situ), while non-infested nuts were cached more often and dispersed farther. Mast seeding had a significant effect on seed predation and dispersal by rodents. When per capita food availability was low (i.e., in non-mast years), harvest rates and dispersal distances (including eaten and cached distances) were obviously accelerated and increased irrespective of insect-infestation. While in mast seed years rodents chose to cache more nuts, and selectively caching a higher proportion of non-infested seeds. This indicated that mast seeding could promote seed caching and result in more seeds escaping predation, which would enhance seed germination and forest regeneration.

An omnivorous mesopredator modifies predation of omnivore‐dispersed seeds

AbstractPost‐dispersal seed predation is an important determinant of plant recruitment. Although many plant species are dispersed following consumption by omnivorous vertebrates, the potential for these dispersal agents to indirectly affect seed fate by modifying seed predator behavior is poorly understood. We evaluated the hypothesis that the scat of an omnivorous vertebrate (coyote, Canis latrans), which is also a rodent predator, would reduce seed predation by rodent granivores. We also hypothesized that scat would lead to increased removal by arthropod seed predators by providing a resource that attracts ants and other arthropods. We examined the role of omnivore deposition on seed predation of two animal‐dispersed species that differed in size: Larger Prunus serotina seeds are attacked only by rodents, whereas smaller Rubus allegheniensis seeds are attacked by arthropods and rodents. Using an experiment that manipulated the presence of coyote scat and access by different granivore guilds, we found that scat reduced the total number of seeds removed from full‐access depots by 12%, but it increased the total number of seeds removed from arthropod‐only depots by 43%. Rodent removal of P. serotina seeds was 21% lower in the presence of scat. Scat composition was also important in affecting rodent seed predation, with seed predation 50% lower in the presence of meat‐rich scat compared with mixed or fruit‐rich scat. Arthropod removal of R. allegheniensis seeds was 43% higher in the presence of scat. Prunus serotina seeds were generally removed at greater rates than R. allegheniensis seeds in full‐access trays; however, scat reduced this difference in removal rates from 37% more P. serotina seeds removed to 18% more P. serotina seeds removed. These findings illuminate a new pathway through which omnivores may influence plant populations by modifying post‐dispersal seed predation by arthropods and rodents. Moreover, our results indicate that the ultimate effect of vertebrate omnivores on seed survival in a given region may depend upon omnivore diet, dominant seed predator guilds, and differences in granivore seed preference.

The Gaze Communications Between Dogs/Cats and Humans: Recent Research Review and Future Directions.

Dogs (Canis familiaris) and cats (Felis silvestris catus) have been domesticated through different processes. Dogs were the first domesticated animals, cooperating with humans by hunting and guarding. In contrast, cats were domesticated as predators of rodents and lived near human habitations when humans began to settle and farm. Although the domestication of dogs followed a different path from that of cats, and they have ancestors of a different nature, both have been broadly integrated into—and profoundly impacted—human society. The coexistence between dogs/cats and humans is based on non-verbal communication. This review focuses on “gaze,” which is an important signal for humans and describes the communicative function of dogs’ and cats’ eye-gaze behavior with humans. We discuss how the function of the gaze goes beyond communication to mutual emotional connection, namely “bond” formation. Finally, we present a research approach to multimodal interactions between dogs/cats and humans that participate in communication and bond formation.

New insights on the infection of pathogenic Leptospira species in American mink (Neovison vison) in southern Chile.

Leptospirosis is a zoonosis of global distribution, caused by the infection of pathogenic Leptospira, a group of bacteria capable of infecting both domestic and wild animals. Mink (Neovison vison) in southern Chile is recognized as a wild and synanthropic rodent predator (among various other prey), and Leptospira infection in them can be acquired through contact with the pathogen in the environment or by eating infected prey. Thus, the aim of this study was to provide more specifics regarding the source of the infection for the American mink under the conditions of Southern Chile. Minks were captured in the Los Ríos region, southern Chile, in an area with well-developed dairy farming. Two areas were selected for mink trapping, one with a high degree of dairy farming and a second with a low degree of dairy farming. Within them, 16 study sites were visited, and 45 American mink were trapped and euthanized to obtain kidney tissue and blood serum samples for bacteria isolation and determination of antibodies titers, respectively. Molecular characterization of the isolated strains was performed. Three minks from sites of high-dairy farming industry and only one from sites with low-degree dairy farming were detected as infected through molecular confirmation. This study shows evidence that confirms previous findings made in southern Chile, regarding mink as host of Leptospira interrogans serovar Hardjo-prajitno associated to cattle-farming areas. However, typing information ( Leptospira interrogans Copenhageni and Icterohaemorrhagiae ) suggests that the consumption of rodents may also be a potential source of infection.