Predatory Strategies Research Articles

The influence of spatial context on prey manipulation behaviors in the California moray eel (Gymnothorax mordax)

Predation strategies are shaped by multiple factors, such as prey type, prey density, and/or abiotic conditions. However, limited research has investigated the role of spatial constraints on post-capture prey behaviors. Our aim was to assess the impact of spatial context on prey manipulation in the California moray eel (Gymnothorax mordax), a crevice forager with a diverse prey handling repertoire. We first compared the duration engaged in specific manipulation behaviors between spatially “enclosed” and “open” foraging environments, followed by a comparison of tightly enclosed spaces that were scaled to individual moray diameter. We observed that the durations spent engaged in specific manipulation behaviors varied based on spatial context. Despite these changes, total feeding time, which consists of both manipulating and swallowing prey, did not vary across treatments. These results highlight the behavioral flexibility of morays, suggesting that they can adjust prey manipulation strategies for specific spatial contexts without compromising overall feeding duration. We additionally documented two previously undescribed behaviors (tail and body anchoring) which seem to be used in the narrowest treatments for leverage when knotting behavior was not possible due to spatial constraints. This research provides valuable insight into the foraging ecology of this locally abundant apex predator and aids in furthering our understanding of predator-prey interactions in the benthic community within the kelp forest ecosystem.

Mothballing as a Predatory Strategy

Abstract The deregulation of the electricity sector in Europe since the early 1990s led to new challenges. In particular, investors are increasingly exposed to risk and mothballing is an option of increasing interest and regulatory scrutiny. I argue that mothballing can be used to avoid losing the war of attrition of a standard exit game, by decreasing the value of rivals and driving them to quit earlier than if the plant was retired. I describe this phenomenon through the lens of simple game-theoretical settings, and propose a real-options game-theoretic model to describe and quantify the effects of mothballing.

Mechanism of bacterial predation via ixotrophy.

Ixotrophy is a contact-dependent predatory strategy of filamentous bacteria in aquatic environments for which the molecular mechanism remains unknown. We show that predator-prey contact can be established by gliding motility or extracellular assemblages we call "grappling hooks." Cryo-electron microscopy identified the grappling hooks as heptamers of a type IX secretion system substrate. After close predator-prey contact is established, cryo-electron tomography and functional assays showed that puncturing by a type VI secretion system mediated killing. Single-cell analyses with stable isotope-labeled prey revealed that prey components are taken up by the attacker. Depending on nutrient availability, insertion sequence elements toggle the activity of ixotrophy. A marine metagenomic time series shows coupled dynamics of ixotrophic bacteria and prey. We found that the mechanism of ixotrophy involves multiple cellular machineries, is conserved, and may shape microbial populations in the environment.

The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation.

Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, antipredator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to "leap" to the next level.

Molecular regulation of reversible cardiac remodeling: lessons from species with extreme physiological adaptations.

Some vertebrates evolved to have a remarkable capacity for anatomical and physiological plasticity in response to environmental challenges. One example of such plasticity can be found in the ambush-hunting snakes of the genus Python, which exhibit reversible cardiac growth with feeding. The predation strategy employed by pythons is associated with months-long fasts that are arrested by ingestion of large prey. Consequently, digestion compels a dramatic increase in metabolic rate and hypertrophy of multiple organs, including the heart. In this Review, we summarize the post-prandial cardiac adaptations in pythons at the whole-heart, cellular and molecular scales. We highlight circulating factors and cellular signaling pathways that are altered during digestion to affect cardiac form and function and propose possible mechanisms that may drive the post-digestion regression of cardiac mass. Adaptive physiological cardiac hypertrophy has also been observed in other vertebrates, including in fish acclimated to cold water, birds flying at high altitudes and exercising mammals. To reveal potential evolutionarily conserved features, we summarize the molecular signatures of reversible cardiac remodeling identified in these species and compare them with those of pythons. Finally, we offer a perspective on the potential of biomimetics targeting the natural biology of pythons as therapeutics for human heart disease.

Evidence for a by‐product mutualism in a group hunter depends on prey movement state

Abstract Group‐hunting animals have been shown to engage their prey in long pursuits (kms) to increase capture success, but the evidence for this is limited to a few terrestrial species. This predation strategy may be effective in the open‐ocean, where group‐hunts are characterised by large predator–prey size ratios and there are few places for prey to hide. However, recording the attack rates, capture rates and capture success probabilities of grouping predators during long‐distance pursuits through the open ocean, remains a significant challenge. Here we use a combination of underwater and aerial video to assess the attack and capture behaviour of striped marlin, Kajikia audax, in relation to the movement of their schooling prey (‘stationary’ and ‘mobile’ movement states) during group hunts. We found that the attack rate was higher when the prey school was ‘stationary’ and, during these times, individual marlin could make longer sequences of uninterrupted attacks on the prey school, effectively monopolising the prey resource for short periods over conspecifics. When the prey school was ‘mobile’, the attack pattern changed and individual marlin alternated their attacks on the prey school more frequently. Capture success probability (likelihood of capture per attack) was not affected by prey movement state. However, attacks on ‘mobile’ schools resulted in more prey fish becoming isolated from the school, and these isolated prey were easily captured—not by the attacker but by conspecifics swimming nearby. The likelihood of a prey becoming isolated from a ‘mobile’ school was predicted by prey school speed, with a 0.1 m s−1 increase leading to an 18.01% increase in the chance of isolation. Altogether this meant the capture rate at the group level was highest when the prey school was ‘mobile’ rather than ‘stationary’ because the predators that were pursuing the ‘mobile’ prey school had an increased availability of isolated and easy to capture prey. This mechanism provides evidence for a by‐product mutualism selecting for conspecific group formation and we discuss our findings in consideration of the social structure of the hunting group and the type of prey. Read the free Plain Language Summary for this article on the Journal blog.

A new species of Nabidae (Hemiptera, Heteroptera, Cimicomorpha) from Dominican amber

ABSTRACT A new species Arachnocoris furtivinabis Ma, Du et Yao sp. nov. is described and illustrated, which represents the first fossil record of Arachnocoris, also the first record in the family Nabidae from Cenozoic Dominican amber. Based on the distinctive morphological characters in this new species, including antennomere II much shorter than twice of antennomere I, labial segment III slightly longer than segment II, and parameres round, it is differentiated from other species within Arachnocoris. Compared with the spider-webdwelling taxa of the extant and extinct species in Heteroptera, the evolution of predation strategies for this special group during the Miocene was discussed.

Leeches Predate on Fast-Escaping and Entangling Blackworms by Spiral Entombment.

We investigate how the Helobdella sp. freshwater leeches capture and consume Lumbriculus variegatus blackworms despite the blackworm's ultrafast helical swimming escape reflex and ability to form large tangled "blobs". We describe a spiral "entombment" predation strategy, where Helobdellid leeches latch onto blackworms with their anterior sucker and envelop them in a spiral cocoon. Quantitative analysis shows that larger leeches succeed more often in entombing prey, while longer worms tend to escape. The rate of spiral contraction correlates with entombment outcomes, with slower rates associated with success. These insights highlight the complex interactions between predator and prey in freshwater ecosystems, providing new perspectives on ecological adaptability and predator-prey dynamics.

Load Balancing in Cloud Computing Using Meta-Heuristic Algorithm: Survey

Load balancing is essential within the cloud. Distributing the workload over many servers permits for a more efficient machine. Optimal resource use, decreased time to response, and more advantageous gadget performance are all results. Among the numerous challenges that traditional methods of accomplishing equilibrium come upon are problems with adaptability and the unpredictability of cloud structures. This survey focuses on the demanding situations associated with load balancing in cloud computing and proposes the usage of specialized algorithms as an answer. It determines the most reliable alternatives for facts placement in the cloud. Meta-heuristic algorithms draw concept from herbal approaches, which includes the foraging behavior of ants or the hunting strategies of predators. These algorithms excel at rapidly finding super answers in situations where conventional optimization algorithms fail to get great results. Various strategies have been proposed to attain paintings equilibrium in cloud computing. Evidence has shown that these techniques can enhance work balance in cloud computing.

A revised classification of the assassin bugs (Hemiptera: Heteroptera: Reduviidae) based on combined analysis of phylogenomic and morphological data

AbstractAssassin bugs (Hemiptera: Reduviidae Latreille) comprise not only one of the largest radiations of predatory animals (22 subfamilies; >6,800 spp.) but also include the medically important kissing bugs (Triatominae Jeannel). Reduviidae are morphologically diverse, engage in an astounding array of predatory strategies and have evolved some of the most unique anti‐predator and stealth techniques in the animal kingdom. While significant progress has been made to reveal the evolutionary history of assassin bugs and revise their taxonomy, the non‐monophyly of the second largest assassin bug subfamily, Reduviinae Latreille, remains to be addressed. Leveraging phylogenomic data (2,291 loci) and 112 morphological characters, we performed the first data‐ and taxon‐rich (195 reduvioid taxa) combined phylogenetic analysis across Reduvioidea and reconstructed morphological diagnostic features for major lineages. We corroborated the rampant polyphyly of Reduviinae that demands substantial revisions to the subfamilial and tribal classification of assassin bugs. Our new classification for Reduviidae reduces the number of subfamilies to 19 and recognizes 40 tribes. We describe three new subfamilies to accommodate distantly related taxa previously classified as Reduviinae (Heteropinae subfam. nov., Nanokeralinae subfam. nov., and Pasirinae subfam. nov.). Triatominae sensu nov. are expanded to include closely related predatory reduviine genera. Cetherinae Jeannel, Chryxinae Champion, Pseudocetherinae Villiers, Salyavatinae Amyot & Serville and Sphaeridopinae Amyot & Serville are treated as junior synonyms of Reduviinae sensu nov. Epiroderinae Distant are synonymized with Phimophorinae Handlirsch sensu nov. and Bactrodini Stål stat. nov. are reclassified as a tribe of Harpactorinae Amyot & Serville. Psophidinae Distant is treated as a valid subfamily. This new classification represents a robust framework for future taxonomic and evolutionary research on assassin bugs.Zoobank Registration: http://zoobank.org/urn:lsid:zoobank.org:pub:2310C9AA-0D53-4EF6-9E75-C2B3A98CE096

Lévy flights, optimal foraging strategies, and foragers with a finite lifespan

In some recent work, we have introduced some efficiency functionals to account for optimal dispersal strategies of predators in search of food. The optimization parameter in this framework is given by the L\'evy exponent of the dispersal of the predators. In this paper, we apply our model to the case of foragers with finite lifetime (i.e., foragers which need to eat a certain amount of food in a given time, otherwise they die). Specifically, we consider the case in which the initial distribution of the forager coincides with a stationary distribution of the targets and we determine the optimal L\'evy exponent for the associated efficiency functional. Namely, we show that if the Fourier transform of the prey distribution is supported in a sufficiently small ball, then the optimizer is given by a Gaussian dispersal, and if instead the Fourier transform of the prey distribution is supported in the complement of a suitable ball, then the ballistic diffusion provides an optimizer (precise conditions for the uniqueness of these optimizers are also given).

Social predation by a nudibranch mollusc.

Social predation is a common strategy used by predators to subdue and consume prey. Animals that use this strategy have many ways of finding each other, organizing behaviors and consuming prey. There is wide variation in the extent to which these behaviors are coordinated and the stability of individual roles. This study characterizes social predation by the nudibranch mollusc, Berghia stephanieae, which is a specialist predator that eats only the sea anemone, Exaiptasia diaphana. A combination of experimental and modeling approaches showed that B. stephanieae does predate upon E. diaphana in groups. The extent of social feeding was not altered by length of food deprivation, suggesting that animals are not shifting strategies based on internal state. It was unclear what cues the individual Berghia used to find each other; choice assays testing whether they followed slime trails, were attracted to injured anemones, or preferred conspecifics feeding did not reveal any cues. Individuals did not exhibit stable roles, such as leader or follower, rather the population exhibited fission-fusion dynamics with temporary roles during predation. Thus, the Berghia provides an example of a specialist predator of dangerous prey that loosely organizes social feeding, which persists across hunger states and uses temporary individual roles; however, the cues that it uses for aggregation are unknown.

Guarding Against China’s Predatory Acquisition of Foreign Technologies: A Quad Perspective

The study examines the response of the Quad countries (Australia, India, Japan and the United States) to People’s Republic of China (PRC)’s predatory acquisition of foreign technologies. This article looks at PRC’s science and technology (S&T) policy and its relation to the grand strategy of attaining global superpower status. The meteoric rise of the PRC in the last four decades has amazed many. Innovation and technological advancement and their alignment with government policies are important factors in this rise. The study notes that PRC’s S&T policy involves, among others, acquiring foreign technologies through illicit means that include stealing through espionage and sophisticated cyberattacks and forcing overseas companies operating in China to share intellectual property rights with local partners. Alarmed by PRC’s predatory strategy, the Quad countries have taken steps to regulate, and in some cases prohibit, the PRC’s targeted foreign investments and coercive and opportunistic takeovers. The article argues that the Quad countries need to coordinate their efforts to effectively counter PRC’s illicit acquisition of their technologies.

Predation, but not herbivory, declines with elevation in a tropical rainforest

AbstractNaturally, insect herbivore populations are controlled by their plant hosts and predators. These ‘bottom-up’ and ‘top-down’ controls influence leaf area lost to herbivory. Bottom-up control of herbivory may be driven by leaf nutrients and plant defences. Top-down control can be driven by abundance and species richness of natural enemies, host or prey specificity, and predation strategies (e.g., active searching or sit-and-wait ‘ambush’ predation). The relative importance of bottom-up and top-down controls is unresolved but likely to vary spatially and temporally and under different environmental conditions such as changing temperature. We surveyed leaf carbon and nitrogen, leaf area loss, and attacks on plasticine caterpillars across a tropical elevational gradient in Xishuangbanna, Yunnan Provence, China. We show that predatory foraging activity decreases with elevation and temperature, whereas leaf nutrients and leaf area loss from herbivory remains more or less constant. Predation patterns were driven by ants, which are thermophiles and therefore more active, abundant, and diverse at warmer, lower elevations. Leaf nutritional values are important in driving herbivory patterns as herbivory was stable across this gradient, but other factors such as mechanical defences and herbivore-induced plant volatiles demand further study. Elevational studies provide insight into how ecosystem function will shift under climate change. As increasing temperatures following climate change allows predatory groups like ants to exploit higher elevations, top-down control in high elevation habitats could increase, resulting in re-wiring of these ecologically sensitive communities. At the same time, top-down control at lower elevations may be at risk if critical thermal maxima for natural enemies are exceeded.

One size does not fit all: Differential predation on livestock species by leopards (Panthera pardus) in a multiuse landscape in the gangetic plains, India

There are underlying patterns involved in predation, particularly for an adaptable species like leopard. One of them is size of the prey. The selection of a prey by a carnivore is typically determined by the trade-off between energy spent and gained. Here size becomes even more consequential when conflict is involved, but most studies typically map all species as a single entity at a single spatial scale. This study aimed at understanding the multiscale nature of the conflict based on the size livestock attacked by leopards (large stock − cattle and small stock − goat and sheep). The methodology encompassed targeted sampling which included the collection of the GPS locations of the attack sites. Spatial layers of 14 environmental variables that represented three spatial scales i.e. proximate (cache-distance), local (daily-movement), and landscape (home-range) scale were then created through remotely sensed data. After that Generalized additive models were utilized for analysis, with ΔAIC used for model selection and evaluation was performed via AUC and TSS statistic. Our results indicate a spatial distinction in predation strategies. In the final model the statistically significant variables for large stock included a higher proportion of cover, and a lower proportion of settlements at the home-range scale, very low human population density at daily-movement scale, and NDVI representing moderately dense vegetation and terrain ruggedness index representing flat terrain at cache-distance scale. Similarly, for small stock the variables included a higher proportion of agricultural land and NDVI values representing open terrain. The effective degrees of freedom was higher than 2 for most of the variables, indicating non-linear relationships. We inferred that the leopards’ targeted large stock in more secluded dry deciduous forests farther from human settlements, where they may be found grazing alone. In contrast, smaller stock, being easier to catch, are killed more frequently in rugged terrain across a wider scrub landscape with scantier cover. Consequently, this selective selection based on size might have its basis in the perceived risk of being chased off by people and the reward in terms of the size of the acquired meal.

Genomic insights into the cellular specialization of predation in raptorial protists

BackgroundPredation is a fundamental mechanism for organisms to acquire energy, and various species have evolved diverse tools to enhance their hunting abilities. Among protozoan predators, raptorial Haptorian ciliates are particularly fascinating as they possess offensive extrusomes known as toxicysts, which are rapidly discharged upon prey contact. However, our understanding of the genetic processes and specific toxins involved in toxicyst formation and discharge is still limited.ResultsIn this study, we investigated the predation strategies and subcellular structures of seven Haptoria ciliate species and obtained their genome sequences using single-cell sequencing technology. Comparative genomic analysis revealed distinct gene duplications related to membrane transport proteins and hydrolytic enzymes in Haptoria, which play a crucial role in the production and discharge of toxicysts. Transcriptomic analysis further confirmed the abundant expression of genes related to membrane transporters and cellular toxins in Haptoria compared to Trichostomatia. Notably, polyketide synthases (PKS) and l-amino acid oxidases (LAAO) were identified as potentially toxin genes that underwent extensive duplication events in Haptoria.ConclusionsOur results shed light on the evolutionary and genomic adaptations of Haptorian ciliates for their predation strategies in evolution and provide insights into their toxic mechanisms.

A new giant Jurassic lacewing larva reveals a particular aquatic habit and its significance to the palaeoecology

AbstractNeuroptera, as a small relic group of Insecta undergoing a rapid species diversification during the Mesozoic Era, is known by diverse extinct endemic lineages preserved as impression fossils and in amber. The current understanding of Mesozoic neuropterans′ diversity has mainly focused on the adults, because the contemporaneous larvae have been fairly rare especially for the Jurassic lacewings. Herein, a new giant lacewing larva, Natator giganteus gen. et sp. nov., is described from the Middle Jurassic Daohugou Beds of China. The remarkable larva is characterized by its impressively large body size, distinctively elongated cervix, and presence of swimming hairs on legs, which provide direct evidence to reveal an aquatic habit for the Jurassic lacewing larva. The morphological analysis indicates this giant larva would have probably inhabited the benthic environments of Jurassic montane rivers and streams. In addition, its morphological specialization suggests that it might have adopted an ambush predation strategy to catch its prey. The finding enhances our knowledge of the species diversity and morphological plasticity for the Jurassic lacewing larvae, and reveals that the aquatic lineages of Neuroptera exhibited dramatically structural and ecological convergence across the evolutionary process.

Ankylosing spondylitis prediction using fuzzy K-nearest neighbor classifier assisted by modified JAYA optimizer

The diagnosis of ankylosing spondylitis (AS) can be complex, necessitating a comprehensive assessment of medical history, clinical symptoms, and radiological evidence. This multidimensional approach can exacerbate the clinical burden and increase the likelihood of diagnostic inaccuracies, which may result in delayed or overlooked cases. Consequently, supplementary diagnostic techniques for AS have become a focal point in clinical research. This study introduces an enhanced optimization algorithm, SCJAYA, which incorporates salp swarm foraging behavior with cooperative predation strategies into the JAYA algorithm framework, noted for its robust optimization capabilities that emulate the evolutionary dynamics of biological organisms. The integration of salp swarm behavior is aimed at accelerating the convergence speed and enhancing the quality of solutions of the classical JAYA algorithm while the cooperative predation strategy is incorporated to mitigate the risk of convergence on local optima. SCJAYA has been evaluated across 30 benchmark functions from the CEC2014 suite against 9 conventional meta-heuristic algorithms as well as 9 state-of-the-art meta-heuristic counterparts. The comparative analyses indicate that SCJAYA surpasses these algorithms in terms of convergence speed and solution precision. Furthermore, we proposed the bSCJAYA-FKNN classifier: an advanced model applying the binary version of SCJAYA for feature selection, with the aim of improving the accuracy in diagnosing and prognosticating AS. The efficacy of the bSCJAYA-FKNN model was substantiated through validation on 11 UCI public datasets in addition to an AS-specific dataset. The model exhibited superior performance metrics—achieving an accuracy rate, specificity, Matthews correlation coefficient (MCC), F-measure, and computational time of 99.23 %, 99.52 %, 0.9906, 99.41 %, and 7.2800 s, respectively. These results not only underscore its profound capability in classification but also its substantial promise for the efficient diagnosis and prognosis of AS.

The macroevolutionary singularity of snakes.

Snakes and lizards (Squamata) represent a third of terrestrial vertebrates and exhibit spectacular innovations in locomotion, feeding, and sensory processing. However, the evolutionary drivers of this radiation remain poorly known. We infer potential causes and ultimate consequences of squamate macroevolution by combining individual-based natural history observations (>60,000 animals) with a comprehensive time-calibrated phylogeny that we anchored with genomic data (5400 loci) from 1018 species. Due to shifts in the dynamics of speciation and phenotypic evolution, snakes have transformed the trophic structure of animal communities through the recurrent origin and diversification of specialized predatory strategies. Squamate biodiversity reflects a legacy of singular events that occurred during the early history of snakes and reveals the impact of historical contingency on vertebrate biodiversity.

Portia spider algorithm: an evolutionary computation approach for engineering application

The Portia spider, a notable member of the jumping spider family (Salticidae), is widely recognized for its intricate hunting strategies and remarkable problem-solving prowess. Several species fall under the “Portia” genus, with habitats spanning regions in Africa, Asia, and Australia. Demonstrating the ability to tackle new challenges, these spiders can learn and adapt their strategies based on prior experiences. This study introduces the Portia Spider Algorithm (PSA), a swarm-based technique inspired by the unique predatory strategies of the Portia spider. We conducted rigorous assessments of PSA performance against 23 classical test functions, 29 CEC2017 test cases, and 5 engineering optimization tasks. To demonstrate the effectiveness of the PSA, outcomes were juxtaposed with those of renowned algorithms. This paper explores the mechanics, advantages, and potential applications of PSA within the vast domain of computational optimization.Graphical