Solitary Hunting Research Articles

Comparative analysis of codon usage patterns of venom gland-specific honeybee-infecting viruses in solitary hunting and social wasps

To identify the evolutionary traits of honeybee-infecting viruses (HVs), including black queen cell virus (BQCV), deformed wing virus (DWV), and Israeli acute paralysis virus (IAPV), and their adaptation patterns in the venom gland of different hosts, we conducted a comparative analysis of codon usage patterns of venom gland-specific HVs in honeybees, solitary hunting, and social wasps. The nucleotides A and U, as well as the nucleotide composition at the third position of synonymous codons (A3s and U3s), were abundantly present with high frequencies in the polyprotein region of the three HVs in Apis mellifera, solitary hunting, and social wasps. Although the three HVs exhibited a high codon adaptation index, effective number of codons and the frequencies of GC3s were observed to be high and low, respectively, indicating a low codon usage bias in the three HVs. The relative abundance of dinucleotides, nucleotide compositions, and the aromaticity of amino acids might be considered as reasons for the different codon usage patterns of the three HVs in solitary hunting and social wasps compared to A. mellifera. The result of phylogenetic analysis revealed that DWV possesses a unique evolutionary pattern compared to the lineages of Aculeate species, possibly caused by specific ecological interactions. Our study provides further insights into the evolutionary aspects of venom gland-specific HVs in Aculeate species and might contribute as fundamental information for further research on the evolution of HVs.

Behavioural synchronisation between different groups of dogs and wolves and their owners/handlers: Exploring the effect of breed and human interaction.

Dogs have previously been shown to synchronise their behaviour with their owner and the aim of this study was to test the effect of immediate interactions, breed, and the effects of domestication. The behavioural synchronisation test was conducted in outdoor enclosures and consisted of 30 s where the owner/handler was walking and 30 s of standing still. Three studies were conducted to explore the effect of immediate interaction (study A), the effect of breed group (study B), and the effect of domestication (study C). In study A, a group of twenty companion dogs of various breeds were tested after three different human interaction treatments: Ignore, Pet, and Play. The results showed that dogs adjusted their movement pattern to align with their owner's actions regardless of treatment. Furthermore, exploration, eye contact, and movement were all influenced by the owners moving pattern, and exploration also decreased after the Play treatment. In study B, the synchronisation test was performed after the Ignore treatment on three groups: 24 dogs of ancient dog breeds, 17 solitary hunting dogs, and 20 companion dogs (data from study A). Irrespective of the group, all dogs synchronised their moving behaviour with their owner. In addition, human walking positively influenced eye contact behaviour while simultaneously decreasing exploration behaviour. In study C, a group of six socialised pack-living wolves and six similarly socialised pack-living dogs were tested after the Ignore treatment. Interestingly, these animals did not alter their moving behaviour in response to their handler. In conclusion, dogs living together with humans synchronise with their owner's moving behaviour, while wolves and dogs living in packs do not. Hence, the degree of interspecies behavioural synchronisation may be influenced by the extent to which the dogs are immersed in everyday life with humans.

The effects of social rank and payoff structure on the evolution of group hunting.

Group hunting is common among social carnivores, and mechanisms that promote this behavior are a central topic in evolutionary biology. Increased prey capture success and decreased losses from competitors are often invoked as factors promoting group hunting. However, many animal societies have linear dominance hierarchies where access to critical resources is determined by social rank, and group-hunting rewards are shared unequally. Despite this inequality, animals in such societies cooperate to hunt and defend resources. Game theoretic models predict that rank and relative rewards from group hunting vs. solitary hunting affect which hunting strategies will evolve. These predictions are partially supported by empirical work, but data needed to test these predictions are difficult to obtain in natural systems. We use digital evolution to test how social rank and tolerance by dominants of subordinates feeding while sharing spoils from group hunting influence which hunting strategies evolve in digital organisms. We created a computer-simulated world to reflect social and hunting dynamics of spotted hyenas (Crocuta crocuta). We found that group hunting increased as tolerance increased and as the relative payoff from group hunting increased. Also, top-ranking agents were more likely to group hunt than lower-ranking agents under despotic sharing conditions. These results provide insights into mechanisms that may promote cooperation in animal societies structured by dominance hierarchies.

Shedding Lights on Crude Venom from Solitary Foraging Predatory Ant Ectatomma opaciventre: Initial Toxinological Investigation

Some species of primitive predatory ants, despite living in a colony, exercise their hunting collection strategy individually; their venom is painful, paralyzing, digestive, and lethal for their prey, yet the toxins responsible for these effects are poorly known. Ectatomma opaciventre is a previously unrecorded solitary hunting ant from the Brazilian Cerrado. To overcome this hindrance, the present study performed the in vitro enzymatic, biochemical, and biological activities of E. opaciventre to better understand the properties of this venom. Its venom showed several proteins with masses ranging from 1–116 kDa, highlighting the complexity of this venom. Compounds with high enzymatic activity were described, elucidating different enzyme classes present in the venom, with the presence of the first L-amino acid oxidase in Hymenoptera venoms being reported. Its crude venom contributes to a state of blood incoagulability, acting on primary hemostasis, inhibiting collagen-induced platelet aggregation, and operating on the fibrinolysis of loose red clots. Furthermore, the E. opaciventre venom preferentially induced cytotoxic effects on lung cancer cell lines and three different species of Leishmania. These data shed a comprehensive portrait of enzymatic components, biochemical and biological effects in vitro, opening perspectives for bio-pharmacological application of E. opaciventre venom molecules.

Prey Status Affects Paralysis Investment in the Ponerine Ant Harpegnathos venator.

Simple SummarySome ants sting their prey to paralyze or kill them when foraging. Some studies have found that paralysis of prey may also be used in food storage. To further understand the foraging behavior of predatory ants and the underlying mechanism, we systematically observed the foraging behavior of Harpegnathos venator when provided with different types of food, different prey sizes, and different prey numbers, and we studied its paralysis behavior in relation to prey under different food supply conditions through controlled experiments. We found that the stings of Harpegnathos venator completely paralyzed the cockroaches. The stinging time was significantly longer at a higher prey activity level and for larger cockroaches. In addition, there was no significant difference in the stinging time of H. venator for different prey densities. It was much shorter for legless cockroaches than for normal cockroaches. The results showed that the longer the stinging time for similar cockroaches, the longer it took for the prey to revive and move. The results are helpful for further understanding the behavioral mechanism underlying prey storage in predatory insects.The paralysis behavior of some ponerine ants when foraging may be important for food storage and colony development. However, how workers invest in paralysis under different prey circumstances is often overlooked. Here, we report the prey-foraging behavior and paralysis behavior of Harpegnathos venator under different food supply conditions. Solitary hunting was the main foraging mode of H. venator, with occasional simple collective hunting. Nymphal cockroaches with high activity were the most attractive to H. venator. In the experiment, we found that the stings of H. venator completely paralyzed the cockroaches. The stinging time was significantly longer at a higher prey activity level and for larger cockroaches. In addition, there was no significant difference in the stinging time of H. venator for different prey densities. The results showed that the longer similar cockroaches were stung, the longer it took for them to revive and move. These results are helpful for further understanding the behavioral mechanism underlying the food storage of live prey by predatory insects.

Breed group differences in the unsolvable problem task: herding dogs prefer their owner, while solitary hunting dogs seek stranger proximity

The communicating skills of dogs are well documented and especially their contact-seeking behaviours towards humans. The aim of this study was to use the unsolvable problem paradigm to investigate differences between breed groups in their contact-seeking behaviours towards their owner and a stranger. Twenty-four dogs of ancient breeds, 58 herding dogs, and 17 solitary hunting dogs were included in the study, and their behaviour when presented with an unsolvable problem task (UPT) was recorded for 3 min. All breed groups interacted with the test apparatus the same amount of time, but the herding dogs showed a longer gaze duration towards their owner compared to the other groups and they also preferred to interact with their owner instead of a stranger. Interestingly, the solitary hunting dogs were more in stranger proximity than the other groups, and they also showed a preference to make contact with a stranger instead of their owner. Hence, we found differences in contact-seeking behaviours, reflecting the dog–human relationship, between breed groups that might not only be related to their genetic similarity to wolves, but also due to the specific breeding history of the dogs.

A new enemy of Apis mellifera (Hymenoptera: Apidae): First report of Nomamyrmex esenbeckii (Hymenoptera: Formicidae) attacking honey bee colonies

Nomamyrmex esenbeckii, commonly known as the legionary ant, belongs to the group of army ants. This social insect employs a cooperative hunting method that is considered more evolved than solitary hunting ants. Their main preys are other ants and termites. However, in this article, we report for the first time in Mexico the predatory behavior of N. esenbeckii on Apis mellifera colonies.

Niche partitioning between sympatric wild canids: the case of the golden jackal (Canis aureus) and the red fox (Vulpes vulpes) in north-eastern Italy

BackgroundTwo coexisting species with similar ecological requirements avoid or reduce competition by changing the extent of their use of a given resource. Numerous coexistence mechanisms have been proposed, but species interactions can also be aggressive; thus, generally a subordinate species modifies its realized niche to limit the probability of direct encounters with the dominant species. We studied niche partitioning between two sympatric wild canids in north-eastern Italy: the golden jackal and the red fox, which, based on competition theories, have a high potential for competition. We considered four main niche dimensions: space, habitat, time, and diet.ResultsWe investigated three study areas monitoring target species populations from March 2017 to November 2018 using non-invasive monitoring techniques. Red fox presence was ascertained in every study area, while golden jackal presence was not ascertained in one study area, where we collected data regarding wolf presence. Considering the two target species, we observed partial diet partitioning based on prey size, with the golden jackal mainly feeding on wild ungulates and the red fox mainly feeding on small mammals. The two canids had an extensive temporal overlap along the diel cycle, having both predominant crepuscular and nocturnal activity patterns, but marked spatial partitioning and differential use of habitats. The golden jackal proved to be specialist concerning the habitat dimension, while the red fox resulted completely generalist: the former selected less human-modified habitats and avoided intensively cultivated lands, while the latter was present in all habitats, including intensively cultivated lands.ConclusionsThe observed partitioning might be due partially to some ecological adaptations (e.g. specialist vs. generalist use of resources) and specific behaviours (e.g. cooperative vs. solitary hunting) and partially to the avoidance response of the red fox aimed at reducing the probability of direct encounters with the golden jackal.

Variation in the sacroiliac joint in Felidae.

Felidae species show a great diversity in their diet, foraging and hunting strategies, from small to large prey. Whether they belong to solitary or group hunters, the behavior of cats to subdue resisting small or large prey presents crucial differences. It is assumed that pack hunting reduces the per capita risk of each individual. We hypothesize that the sacroiliac articulation plays a key role in stabilizing the predator while subduing and killing prey. Using CT-scan from 59 felid coxal bones, we calculated the angle between both iliac articular surfaces. Correlation of this inter-iliac angle with body size was calculated and ecological stressors were evaluated on inter-iliac angle. Body size significantly influences inter-iliac angle with small cats having a wider angle than big cats. Arboreal species have a significantly larger angle compared to cursorial felids with the smallest value, and to scansorial and terrestrial species with intermediate angles. Felids hunting large prey have a smaller angle than felids hunting small and mixed prey. Within the Panthera lineage, pack hunters (lions) have a larger angle than all other species using solitary hunting strategy. According to the inter-iliac angle, two main groups of felids are determined: (i) predators with an angle of around 40° include small cats (i.e., Felis silvestris, Leopardus wiedii, Leptailurus serval, Lynx Canadensis, L. rufus; median = 43.45°), the only pack-hunting species (i.e., Panthera leo; median = 37.90°), and arboreal cats (i.e., L. wiedii, Neofelis nebulosa; median = 49.05°), (ii) predators with an angle of around 30° include solitary-hunting big cats (i.e., Acinonyx jubatus, P. onca, P. pardus, P. tigris, P. uncia; median = 31.80°). We suggest different pressures of selection to interpret these results. The tightening of the iliac wings around the sacrum probably enhances big cats’ ability for high speed and large prey control. In contrast, pack hunting in lions reduced the selective pressure for large prey.

Long-term stress in dogs is related to the human\u2013dog relationship and personality traits

Previously, we found that dogs belonging to the herding breed group, selected for human cooperation, synchronise their long-term stress levels with their owners. The aim of the current study was to investigate features that could influence long-term stress levels in ancient dog breeds, genetically closer to wolves, and dogs specifically selected to work independently of their owner. Twenty-four ancient breed dogs and 18 solitary hunting dogs were recruited and hair samples were obtained from both dogs and owners from which hair cortisol concentration (HCC) was analysed. Additionally, the owners completed lifestyle surveys, the Monash Dog Owner Relationship Scale (MDORS) on human–dog relationship, and both dog and owner personality questionnaires (Dog Personality questionnaire and Big Five Inventory survey). The results from the MDORS indicate that the subscale Perceived cost correlated to the dog HCC of tested breed groups: solitary hunting breeds (χ2 = 4.95, P = 0.026, β = 0.055), ancient breeds (χ2 = 2.74, P = 0.098, β = 0.027), and herding dogs included from a previous study (χ2 = 6.82, P = 0.009, β = − 0.061). The HCC of the solitary hunting dogs was also related to the owner personality traits Agreeableness (χ2 = 12.30, P < 0.001, β = − 0.060) and Openness (χ2 = 9.56, P = 0.002, β = 0.048) suggesting a more substantial influence of the owner on the solitary hunting dog’s HCC compared to the ancient breeds. No effect of owner HCC on dog HCC was found in either ancient or in solitary hunting breeds. Hence, the long-term stress synchronisation is likely to be a trait in breeds selected for human cooperation. In conclusion, dog HCC is often related to the owners’ personality, but is primarily influenced by the owner-dog relationship.

New evidence for truly gregarious behavior of ornithopods and solitary hunting by a theropod

New evidence for truly gregarious behavior of ornithopods and solitary hunting by a theropod

Heterospecific Foraging Associations Between Reef‐Associated Sharks: First Evidence of Kleptoparasitism in Sharks

Social predation allows groups of predators to search for, pursue, and capture prey with greater efficiency than using solitary hunting. During ~3,000 hours of underwater observations of nocturnal shark foraging activity, we report for the first time a heterospecific association between two shark species, with the nature of the interaction ranging from commensalism to kleptoparasitism and mutualism. These foraging associations with whitetip reef sharks offer grey reef sharks the opportunity to access different types of prey and increase their predation success. These findings add more evidence that heterospecific social associations may exist across animal groups including large marine predators. These photographs illustrate the article “Heterospecific foraging associations between reef-associated sharks: first evidence of kleptoparasitism in sharks” by Pierre Labourgade, Laurent Ballesta, Charlie Huveneers, Yannis Papastamatiou, and Johann Mourier published in Ecology. https://doi.org/10.1002/ecy.3117.

Influence of past and current social contexts on hunting behaviour in spiderlings

When foraging in a group, individuals adjust their behaviours to the actions of others in order to optimize their pay-offs. While many studies have examined the influence of group composition on behavioural strategies, relatively few have investigated how the presence or absence of conspecifics influences the expression of behaviours during hunting. Another aspect that has received little attention concerns the impact of prior social experience on the expression of predatory behaviour. Here, we studied how past and present social contexts influenced predatory behaviour in juveniles of the spider Agelena labyrinthica which, like most solitary species, exhibit a transient gregarious phase prior to dispersal. We tested, alone or in pairs, spiderlings that have been maintained in isolation or in groups for 24 h prior to behavioural assays. During the tests, we introduced a live prey to an experimental arena and we measured the latencies associated with the different phases of the hunting sequence. We found that spiders maintained in isolation captured prey faster than those kept in groups and that the presence of a sibling increased the latency of prey capture compared with individuals hunting alone. Such a social context effect adds another dimension to the already complex combination of factors that determine the success of spider foraging. Overall, our study reveals an influence of the social dimension, past and present, on hunting behaviour that may have been underestimated in carnivores. It is generally considered that hunting in group increases individual benefits compared with solitary hunting. However, relatively few studies have compared hunting performance between individuals hunting alone or in group to assess how the presence of conspecifics impacts the expression of predatory behaviours. Another aspect that has been little explored concerns the role of the social context previously experienced on hunting behaviour. This study examined the influence of past or present social context on hunting behaviour in juveniles of a solitary spider during their gregarious phase. We showed that spiderlings maintained in isolation or tested alone were faster at catching prey than congeners reared socially or tested in groups. This study highlights a cost to sociality that has so far received little attention, and which could be an important element to consider in understanding transitions to permanent sociality.

21. A Stylistic, Spatial and Cultural Assessment of the Bovid Petroglyphs from Humayma

During the summer of 2014, more than 150 petroglyphs were discovered in the sandstone ridges west of the ancient town Hawara (modern day al-Humayma). The site, located in southern Jordan’s Hisma desert, boasts a diverse occupational history spanning from the Neolithic period to the present and representing many diverse cultural groups. The petroglyphs discovered west of the site depict various imagery, including animals, humans, and footprints. Among the animals, various representations of bovids were discovered, including ibex, gazelle and oryx. This study analyzed the bovid petroglyphs, focusing on their spatial relationships with one another and the environment, as well as the various stylistic depictions observed and potential genus identifications. A cultural assessment was also completed to examine the animals’ role through time, and other petroglyph representations discovered in the region were examined to pursue potential meanings for the newly discovered bovid petroglyphs. The petroglyphs depicted different artistic styles and could be sorted into categories based on artistic design and themes. The themes included solitary animals, interacting animals, predator/prey relationships and human hunting. The occurrence of the categories was analyzed across three study areas and in relation to the environment allowing potential explanations for their meanings to be proposed, each linked to the cultural groups that theoretically produced these petroglyphs.

An insulin-binding protein from the venom of a solitary wasp Eumenes pomiformis binds to apolipophorin III in lepidopteran hemolymph

EpIBP, an insulin-like peptide-binding protein, is a major protein component of the venom of a solitary hunting wasp, Eumenes pomiformis. To evaluate the bioactivity, bacteria-expressed EpIBP was injected into Spodoptera exigua larvae, resulting in a higher survival rate and reduced loss of body weight under starvation conditions than control larvae. EpIBP was found to interact with apolipophorin III (apoLp III), implying that EpIBP might function by altering the apoLp III-mediated metabolism of prey.

Benefits of Group Foraging Depend on Prey Type in a Small Marine Predator, the Little Penguin.

Group foraging provides predators with advantages in over-powering prey larger than themselves or in aggregating small prey for efficient exploitation. For group-living predatory species, cooperative hunting strategies provide inclusive fitness benefits. However, for colonial-breeding predators, the benefit pay-offs of group foraging are less clear due to the potential for intra-specific competition. We used animal-borne cameras to determine the prey types, hunting strategies, and success of little penguins (Eudyptula minor), a small, colonial breeding air-breathing marine predator that has recently been shown to display extensive at-sea foraging associations with conspecifics. Regardless of prey type, little penguins had a higher probability of associating with conspecifics when hunting prey that were aggregated than when prey were solitary. In addition, success was greater when individuals hunted schooling rather than solitary prey. Surprisingly, however, success on schooling prey was similar or greater when individuals hunted on their own than when with conspecifics. These findings suggest individuals may be trading-off the energetic gains of solitary hunting for an increased probability of detecting prey within a spatially and temporally variable prey field by associating with conspecifics.

Comparative transcriptome analysis of the venom sac and gland of social wasp Vespa tropica and solitary wasp Rhynchium brunneum

To investigate genes differentially expressed in the venom of social and solitary wasps, a comparative transcriptome analysis was conducted. Subtractive expressed sequence tag (EST) libraries specific to the venom gland and sac (gland/sac) of a social wasp species, Vespa tropica and a solitary hunting wasp species, Rhynchium brunneum, was constructed by suppression subtractive hybridization. In BLASTx analysis, 41% and 56% of the total ESTs showed statistically best-matched hits (E≤10−4) in the libraries of V. tropica and R. brunneum, respectively. Although the functional category analysis did not show remarkable differences in the distribution of functional categories between the two venom gland/sac cDNA libraries, perhaps due to the lack of functional information on many of the venom components, there were groups of genes that are specific to either V. tropica or R. brunneum. Venom allergen 5 and serine protease were found to be social wasp-specific venom transcripts. In contrast, venom peptides, metalloendopeptidases, arginine kinase and dendrotoxin were observed in solitary wasp at much higher frequencies.

A Free Ride and Lunch: Stylopization in the Solitary Hunting Wasp, Ammophila Fernaldi Murray and A. Pictipennis (Walsh) (Hymenoptera: Sphecidae) By Paraxenos Lugubris Pierce (Strepsiptera)

Abstract. The intricate nest building, cleaning and provisioning habits of the solitary hunting wasps Ammophila fernaldi Murray and A. pictipennis (Walsh) (Hymenoptera: Sphecidae) are supposed to have developed in response to parasite pressure. This paper presents the first study to record the behavior of phoresy of Paraxenos lugubris Pierce (Strepsiptera: Stylopidae). Adapting to the provisioning of single-cell nests of the Ammophila sp., it is the tiny, free-living, first instar larvae of P. lugubris, that are phoretic. They are carried, not by a wasp stylopized by a female P. lugubris producing first instar larvae, but by an unstylopized foraging wasp, thereby discreetly gaining entry to a single-cell nest before it is sealed. Multiple first instar P. lugubris larvae are often taken by the host, A. fernaldi and A. pictipennis, to the single egg/ larvae in the cell, resulting in superparasitism. These observations further demonstrate that Strepsiptera have developed mechanisms for parasitizing a range o...

Venom peptides from solitary hunting wasps induce feeding disorder in lepidopteran larvae

The cell lytic activity and toxicity against lepidopteran larvae of 13 venom peptides (4 OdVPs and 9 EpVPs) from two solitary hunting wasps, Orancistrocerus drewseni and Eumenes pomiformis, were examined with mastoparan as a reference peptide. Of the 13 peptides, 7 were predicted to have α-helical structures that exhibit the typical character of amphipathic α-helical antimicrobial peptides. The remaining peptides exhibited coil structures; among these, EpVP5 possesses two Cys residues that form an internal disulfide bridge. All the helical peptides including mastoparan showed antimicrobial and insect cell lytic activities, whereas only two of them were hemolytic against human erythrocytes. The helical peptides induced a feeding disorder when injected into the vicinity of the head and thorax of Spodoptera exigua larvae, perhaps because their non-specific neurotoxic or myotoxic action induced cell lysis. At low concentrations, however, these helical peptides increased cell permeability without inducing cell lysis. These findings suggest that the helical venom peptides may function as non-specific neurotoxins or myotoxins and venom-spreading factors at low concentrations, as well as preservatives for long-term storage of the prey via antimicrobial, particularly antifungal, activities.

Identification and characterization of venom proteins of two solitary wasps, Eumenes pomiformis and Orancistrocerus drewseni

Secretory proteins were identified in the venoms of two solitary hunting wasps, Eumenes pomiformis and Orancistrocerus drewseni, by SDS-PAGE in conjunction with mass analysis. More than 30 protein bands (2–300 kDa) were detected from the crude venom of each wasp. With the aid of the previously constructed venom gland/sac-specific EST libraries, a total of 31 and 20 proteins were identified from 18 to 20 distinctive protein bands of E. pomiformis and O. drewseni venoms, respectively. Arginine kinase was the most predominant protein in both wasp venoms. Along with the full-length arginine kinase, a truncated form, which was known to have paralytic activity on a spider, was a common predominant protein in the two wasp venoms. Insulin/insulin-like peptide-binding protein was abundantly found only in E. pomiformis venom, which might be due to its unique behaviors of oviposition and provision. The presence of various immune response-related proteins and antioxidants suggested that wasps might use their venom to maintain prey fresh while feeding wasp larvae by protecting the prey from microbial invasion and physiological stresses. It seemed that some venom proteins are secreted into venom fluid from venom gland cells via exosomes, not by signal sequence-mediated transport processes.