ABSTRACT
Interactions among species, which range from competition to facilitation, have profound effects on ecosystem functioning. Large carnivores are of particular importance in shaping community ...structure since they are at the top of the food chain, and many efforts are made to conserve such keystone species. Despite this, the mechanisms of carnivore interactions are far from understood, yet they are key to enabling or hindering their coexistence and hence are highly relevant for their conservation. The goal of this review is thus to provide detailed information on the extents of competition and facilitation between large carnivores and their impact in shaping their life histories. Here, we use the example of spotted hyaenas (Crocuta crocuta) and lions (Panthera leo) and provide a comprehensive knowledge of their interactions based on meta‐analyses from available literature (148 publications). Despite their strong potential for both exploitation and interference competition (range and diet overlap, intraguild predation and kleptoparasitism), we underline some mechanisms facilitating their coexistence (different prey‐age selection and scavenging opportunities). We stress the fact that prey abundance is key to their coexistence and that hyaenas forming very large groups in rich ecosystems could have a negative impact on lions. We show that the coexistence of spotted hyaenas and lions is a complex balance between competition and facilitation, and that prey availability within the ecosystem determines which predator is dominant. However, there are still many gaps in our knowledge such as the spatio‐temporal dynamics of their interactions. As both species' survival becomes increasingly dependent on protected areas, where their densities can be high, it is critical to understand their interactions to inform both reintroduction programs and protected area management.
The costs of foraging can be high while also carrying significant risks, especially for consumers feeding at the top of the food chain.
To mitigate these risks, many predators supplement active ...hunting with scavenging and kleptoparasitic behaviours, in some cases specializing in these alternative modes of predation.
The factors that drive differential utilization of these tactics from species to species are not well understood.
Here, we use an energetics approach to investigate the survival advantages of hunting, scavenging and kleptoparasitism as a function of predator, prey and potential competitor body sizes for terrestrial mammalian carnivores.
The results of our framework reveal that predator tactics become more diverse closer to starvation, while the deployment of scavenging and kleptoparasitism is strongly constrained by the ratio of predator to prey body size.
Our model accurately predicts a behavioural transition away from hunting towards alternative modes of predation with increasing prey size for predators spanning an order of magnitude in body size, closely matching observational data across a range of species.
We then show that this behavioural boundary follows an allometric power‐law scaling relationship where the predator size scales with an exponent nearing 3/4 with prey size, meaning that this behavioural switch occurs at relatively larger threshold prey body size for larger carnivores.
We suggest that our approach may provide a holistic framework for guiding future observational efforts exploring the diverse array of predator foraging behaviours.
Our paper presents a theoretical framework predicting behavioural transitions in large carnivores, from hunting to scavenging to stealing, based on predator and prey body size. We reveal how these strategies are not random but follow a predictable pattern dictated by the predator's body size, offering insights into the foraging ecology of mammalian carnivores. Description: Lions consume a giraffe carcass in Ruaha National Park, Tanzania. Photo credit: Chris Darimont.
The social environment can play an important role in shaping the foraging behaviour of animals. In this study we investigated whether archerfish, Toxotes jaculatrix, display any behavioural changes ...in response to the presence of an audience while using their specialized foraging tactic of shooting, spitting precisely aimed jets of water, at prey targets. As any prey items shot down are potentially available to competitors, we hypothesized that shooting fish would be sensitive to the presence of potential competitors, especially given the suggestion that, in the wild, this species shows intraspecific kleptoparasitism and faces interspecific competition. We found that in the presence of another fish, archerfish took longer to shoot, made more orientations (aiming events) per shot, and tended to be closer to the target at the time of shooting. Additionally, archerfish showed high interindividual differences in latency to shoot, and these differences were consistent across contexts, with and without an audience. Our results show that archerfish are sensitive to, and adjust their shooting behaviour in response to, the presence of an audience and highlight the importance of social context in this fish species. We also suggest that interindividual differences may play an important role in archerfish shooting behaviour. This study highlights the importance of social effects and competition on foraging behaviour and decision making. Further work in this species could explore whether differences in competitive foraging ability are linked to sensitivity to the presence of an audience.
•Archerfish prey shooting behaviour is affected by the presence of conspecifics.•Latency to shoot and number of aiming events increased with an audience.•Archerfish show consistent interindividual differences in latency to shoot.
Pumas (Puma concolor) are solitary large carnivores that exhibit high energetic investments while hunting prey that often take multiple days to consume. Therefore, pumas should behave in a way to ...maximize their energetic gains, including using caching, which is a behavior used by many mammal species to preserve and store food or to conceal it from conspecifics and scavengers to limit their losses. Yet pumas do not always cache their kills. In order to understand caching behavior, we used variables associated with the kills such as prey mass, search time, climate, and habitat to test 20 ecological models (representing four a priori hypotheses: food perishability, resource pulse, consumption time, and kleptoparasitism deterrence) in an information-theoretic approach of model selection to explore factors related to the caching behavior. Models were run with information from tracked radio-collared pumas in California over a 2.5-year period and identified a total of 352 kills. Overall, we documented pumas caching 61.5% of their kills, including 71.6% of Black-tailed Deer (Odocoileus hemionus columbianus), their primary prey in the study area. The model with a quadratic effect of adjusted mass of prey on puma caching probability had all of the empirical support (w = 1.00). Specifically, pumas were most likely to cache intermediate-sized prey, such as yearling and adult female deer, and also fed from cached kills for longer periods of time. Larger prey may be too large to easily cache, making it less energetically efficient—while small prey can often be consumed quickly enough to not require caching. This suggests that intermediate-sized prey may be the optimal size for caching, allowing a puma to feed for multiple days while not greatly increasing energetic output. The hypotheses we tested were not mutually exclusive and pumas caching their prey may occur for several reasons; nevertheless, our study demonstrated that pumas use caching to extend their foraging time and maximize energetic gains when preying on intermediate-sized prey. El esconder comida es un comportamiento utilizado por muchas especies, entre ellos los carnívoros, para conservar y almacenar alimentos u ocultarlos de congéneres y de carroñeros. Los pumas (Puma concolor) son grandes carnívoros solitarios que invierten gran cantidad de energía en cazar sus presas, que a menudo tardan varios días en consumir. Por lo tanto, los pumas deberían comportarse de manera que puedan maximizar sus ganancias energéticas, incluyendo el esconder su comida para reducir las pérdidas a manos de vertebrados carroñeros; sin embargo, los pumas no siempre esconden sus presas. En California rastreamos pumas con radio collares durante 2años y medio, e identificamos 352 presas cazadas. Usando variables asociadas a las cacerías, probamos 20 modelos, que representan 4 hipótesis a priori (alimento-caducidad, recurso-pulso, consumo-tiempo y cleptoparasitismo-disuasión), con un enfoque teórico de la información para explorar factores relacionados con el comportamiento de esconder el alimento. En general, documentamos que los pumas escondieron el 61,5% de sus presas, de las cuales 71,6% eran de ciervo de cola negra (Odocoileus hemionus columbianus), su principal presa en el área de estudio. El modelo con efecto cuadrático de la masa corporal de la presa ajustada (proporción de peso de presa:peso de puma) sobre la tasa de escondido de presa del puma tuvo todo el soporte (w = 1,00). Específicamente, era más probable que los pumas escondieran presas de tamaño intermedio, como ciervos jóvenes de un año y hembras adultas, y los pumas también se alimentaban de las presas escondidas durante períodos de tiempo más largos, lo que respalda la hipótesis de que este comportamiento incrementa la energía ganada. Las presas más grandes pueden ser demasiado grandes para esconderlas fácilmente, haciendo que la actividad sea menos eficiente desde el punto de vista energético, mientras que las presas pequeñas a menudo se pueden consumir lo suficientemente rápido como para no requerir ser escondidas. Esto sugiere que las presas de tamaño intermedio pueden ser el tamaño óptimo para ser escondidas, lo que permite que un puma se alimente durante varios días sin ser energéticamente costoso. Las hipótesis que probamos no son mutuamente excluyentes, por lo que el esconder las presas puede ocurrir por varias razones. nuestro estudio ilustra cómo los pumas suelen esconder su alimento para extender su tiempo de alimentación y maximizar las ganancias energéticas al consumir presas de tamaño intermedio.
Kleptoparasitism is a foraging strategy where one individual steals a procured food item from another individual. Individual kleptoparasites can optimize their foraging strategy by targeting more ...profitable hosts or by modifying their behaviour to expend less energy than they would by foraging independently. Herring gulls, Larus argentatus, kleptoparasitize Atlantic puffins, Fratercula arctica, by intercepting adults as they return to their burrows with fish for their chicks. While this system has been studied extensively, much remains unknown, particularly from the herring gull's perspective. We tested predictors of herring gull host choice and the probability of success during kleptoparasitic attacks by conducting 73 30-minute focal samples of individual herring gulls at a breeding colony in Newfoundland, Canada. We recorded each puffin that approached the focal gull, categorizing them according to prey type carried, whether or not they landed, and whether or not they were attacked. For those puffins that were attacked, we also noted whether the gull succeeded in obtaining prey. Herring gulls did not attack puffins at random, but, rather, preferentially attacked puffins that carried larger prey, had already completed their landing, and landed closer to and/or in front of the gull. Gulls tended to be more successful at stealing a puffin's food when they attacked landed puffins and made physical contact with the puffin, but not when the puffin landed closer to them or when they were oriented towards the puffin. These findings suggest that herring gulls optimize their kleptoparasitic foraging strategy by targeting more profitable hosts.
•Kleptoparasitism, or stealing another's food, can be an efficient foraging strategy.•Herring gulls do not kleptoparasitize Atlantic puffins at random.•Gulls preferentially targeted more profitable hosts.•Focal gulls attacked 7.7% of approaching provisioning puffins.•Gulls were successful in more than 25% of attacks on landed puffins.
1. Food caching is a common strategy used by a diversity of animals, including carnivores, to store and/or secure food. Despite its prevalence, the drivers of caching behaviour, and its impacts on ...individuals, remain poorly understood, particularly for short-term food cachers. 2. Leopards Panthern pardus exhibit a unique form of short-term food caching, regularly hoisting, storing and consuming prey in trees. We explored the factors motivating such behaviour among leopards in the Sabi Sand Game Reserve, South Africa, associated with four not mutually exclusive hypotheses: food-perishability, consumption-time, resource-pulse and kleptoparasitism-avoidance. 3. Using data from 2032 prey items killed by 104 leopards from 2013 to 2015, we built generalized linear mixed models to examine how hoisting behaviour, feeding time and the likelihood of a kill being kleptoparasitized varied with leopard sex and age, prey size and vulnerability, vegetation, elevation, climate, and the immediate and long-term risk posed by dominant competitors. 4. Leopards hoisted 51% of kills. They were more likely to hoist kills of an intermediate size, outside of a resource pulse and in response to the presence of some competitors. Hoisted kills were also fed on for longer than non-hoisted kills. At least 21% of kills were kleptoparasitized, mainly by spotted hyaenas Crocuta crocuta. Kills were more likely to be kleptoparasitized at lower temperatures and if prey were larger, not hoisted, and in areas where the risk of encountering hyaenas was greatest. Female leopards that suffered higher rates of kleptoparasitism exhibited lower annual reproductive success than females that lost fewer kills. 5. Our results strongly support the kleptoparasitism-avoidance hypothesis and suggest hoisting is a key adaptation that enables leopards to coexist sympatrically with high densities of competitors. We further argue that leopards may select smaller-sized prey than predicted by optimal foraging theory, to balance trade-offs between kleptoparasitic losses and the energetic gains derived from killing larger prey. 6. Although caching may provide the added benefits of delaying food perishability and enabling consumption over an extended period, the behaviour primarily appears to be a strategy for leopards, and possibly other short-term cachers, to reduce the risks of kleptoparasitism.
The Sarcophagidae (flesh flies) comprise a large and widely distributed radiation within the Calyptratae (Diptera). Larval feeding habits are ecologically diverse and include sarcosaprophagy, ...coprophagy, herbivory, invertebrate and vertebrate predation, and kleptoparasitism. To elucidate the geographic origin and evolution of flesh fly life‐history, we inferred a backbone phylogeny based on transcriptomic data from 26 sarcophagid species covering all three subfamilies plus 15 outgroups. The phylogeny was inferred using maximum parsimony and maximum likelihood methods based on a series of supermatrices, one set with overall information content improved by MARE (2290 loci), one set with 100% gene coverage for all included species (587 loci), and the last set including mitochondrial and nuclear genes (589 loci) and additional taxa. In order to obtain a more detailed hypothesis, we utilized the supertree approach to combine results from the present study with previously published hypotheses. This resulted supertree covers 84 of the one hundred currently recognized sarcophagid genera and formed the basis for the ancestral state reconstructions. The monophyletic Sarcophagidae is well‐supported as sister to {Mystacinobiidae + Oestridae}, and relationships at the subfamily level are inferred as {Sarcophaginae, (Paramacronychiinae + Miltogramminae)}. The Sarcophagidae and each subfamily originated in the Americas, with Sarcophaginae diversifying mainly in the Neotropics, whereas the major radiation of both Miltogramminae and Paramacronychiinae occurred in the Palaearctic. Sarcosaprophagy is reconstructed as the ancestral larval feeding habit of the family Sarcophagidae and each subfamily. The ancestral sarcophagid larva probably utilized dead invertebrates as food, and the food spectrum expanded together with the diversification of breeding strategies. Particularly, kleptoparasitism in Miltogramminae is derived from sarcosaprophagy and may be seen as having derived from the breeding biology of ‘lower’ miltogrammines, the larvae of which feed on buried vertebrate carrion.
Abstract
Mutualistic interactions between butterflies and ants can evolve into complex social parasitism. ‘Cuckoo’ caterpillars, known only in the Lycaenidae, use multimodal mimetic traits to achieve ...social integration into ant societies. Here, we present the first known ‘cuckoo’ butterfly in the family Riodinidae. Aricoris arenarum remained in taxonomic limbo for > 80 years, relegated to nomen dubium and misidentified as Aricoris gauchoana. We located lost type material, designated lectotypes and documented the morphology and natural history of the immature stages. The multifaceted life cycle of A. arenarum can be summarized in three phases: (1) females lay eggs close to honeydew-producing hemipterans tended by specific Camponotus ants; (2) free-living caterpillars feed on liquids (honeydew and ant regurgitations); and (3) from the third instar onward, the caterpillars are fed and tended by ants as ‘cuckoos’ inside the ant nest. This life cycle is remarkably similar to that of the Asian lycaenid Niphanda fusca, despite divergence 90 Mya. Comparable eco-evolutionary pathways resulted in a suite of ecomorphological homoplasies through the ontogeny. This study shows that convergent interactions can be more important than phylogenetic proximity in shaping functional traits of social parasites.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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