Hunting behaviour, prey capture and ant avoidance in the tropical social waspPolybia sevicea (Hymenoptera: Vespidae)

1991 ◽  
Vol 38 (2) ◽  
pp. 139-147 ◽  
Author(s):  
M. Raveret Richter ◽  
R. L. Jeanne
Keyword(s):  
Prey Capture ◽  
Hunting Behaviour

scholarly journals Parallel channels for motion feature extraction in the pretectum and tectum of larval zebrafish

2019 ◽  
Author(s):  
Kun Wang ◽  
Julian Hinz ◽  
Yue Zhang ◽  
Tod R. Thiele ◽  
Aristides B Arrenberg
Keyword(s):  
Feature Extraction ◽  
Visual Field ◽  
Prey Capture ◽  
Receptive Fields ◽  
Lower Visual Field ◽  
Motion Feature ◽  
Hunting Behaviour ◽  
Sensorimotor Transformations ◽  
Visual Areas ◽  
Tectal Neurons

AbstractNon-cortical visual areas in vertebrate brains extract different stimulus features, such as motion, object size and location, to support behavioural tasks. The optic tectum and pretectum, two primary visual areas, are thought to fulfil complementary biological functions in zebrafish to support prey capture and optomotor stabilisation behaviour. However, the adaptations of these brain areas to behaviourally relevant stimulus statistics are unknown. Here, we used calcium imaging to characterize the receptive fields of 1,926 motion-sensitive neurons in diencephalon and midbrain. We show that many caudal pretectal neurons have large receptive fields (RFs), whereas RFs of tectal neurons are smaller and mostly size-selective. RF centres of large-size RF neurons in the pretectum are predominantly located in the lower visual field, while tectal neurons sample the upper-nasal visual field more densely. This tectal visual field sampling matches the expected prey item locations, suggesting that the tectal magnification of the upper-nasal visual field might be an adaptation to hunting behaviour. Finally, we probed optomotor responsiveness and found that even relatively small stimuli drive optomotor swimming, if presented in the lower-temporal visual field, suggesting that the pretectum preferably samples information from this region on the ground to inform optomotor behaviour. Our characterization of the parallel processing channels for non-cortical motion feature extraction provides a basis for further investigation into the sensorimotor transformations of the zebrafish brain and its adaptations to habitat and lifestyle.

Notes on the diet and foraging habits of the Giant Barred Frog Mixophyes iteratus

2020 ◽  
Author(s):  
G. Madani
Keyword(s):  
Stomach Content ◽  
Prey Capture ◽  
Limited Information ◽  
Foraging Patterns ◽  
Faecal Analysis ◽  
Hunting Behaviour ◽  
Direct Observations ◽  
Ambush Predators

Australian anurans generally display little prey specialisation. Most data available of frog diet is limited to stomach content and faecal analysis with few direct observations of prey capture. Limited information is available on the diet of adult Giant Barred Frogs Mixophyes iteratus. In this paper I report on several observations of M. iteratus feeding on a variety of prey from various taxa. These observations suggest that M. iteratus are opportunistic, ambush predators with a broad diet. Their morphology and hunting behaviour align with existing models of amphibian foraging patterns.

scholarly journals Past thermal conditions affect hunting behaviour in larval antlions

2021 ◽  
Vol 8 (6) ◽  
pp. 210163
Author(s):  
Krzysztof Miler ◽  
Marcin Czarnoleski
Keyword(s):  
Elevated Temperatures ◽  
Prey Capture ◽  
Thermal Conditions ◽  
Thermal Exposure ◽  
Hunting Behaviour ◽  
Abiotic And Biotic Factors ◽  
Trap Size ◽  
Harsh Conditions ◽  
Antlion Larvae ◽  
Past Conditions

Some sit-and-wait predators, such as antlion larvae, construct traps to capture passing prey. The location of these traps depends on many abiotic and biotic factors, including temperature and the presence of conspecifics, which probably stimulate behaviours that minimize the costs and maximize the benefits of trap building. Here, we exposed second instar antlion larvae to elevated temperatures of 25°C (mild treatment) or 31°C (harsh treatment) for one month and then transferred them to common conditions (20°C) to examine the effects of previous thermal treatment on aggregation tendency and trap size. We predicted that antlions that experienced harsh conditions would subsequently increase the neighbouring distance and trap diameter to reduce competition with conspecifics and improve prey capture success, compensating for past conditions. In contrast with these predictions, antlions exposed to harsh conditions displayed a trend in the opposite direction, towards the decreased neighbouring distance. Furthermore, some of these antlions also built smaller traps. We discuss possible reasons for our results. The effects of previous thermal exposure have rarely been considered in terms of trap construction in antlions. Described effects may possibly apply to other sit-and-wait predators and are significant considering that many of these predators are long-lived.

scholarly journals First evidence of underwater vocalisations in hunting penguins

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8240 ◽  
Author(s):  
Andréa Thiebault ◽  
Isabelle Charrier ◽  
Thierry Aubin ◽  
David B. Green ◽  
Pierre A. Pistorius
Keyword(s):  
Prey Capture ◽  
Group Formation ◽  
Maximum Amplitude ◽  
Sea Surface ◽  
Foraging Success ◽  
Video Cameras ◽  
Marine Predators ◽  
Hunting Behaviour ◽  
Study Species ◽  
Behavioural Adaptations

Seabirds are highly vocal on land where acoustic communication plays a crucial role in reproduction. Yet, seabirds spend most of their life at sea. They have developed a number of morphological, physiological and behavioural adaptations to forage in the marine environment. The use of acoustic signals at sea could potentially enhance seabirds’ foraging success, but remains largely unexplored. Penguins emit vocalisations from the sea surface when commuting, a behaviour possibly associated with group formation at sea. Still, they are unique in their exceptional diving abilities and feed entirely underwater. Other air-breathing marine predators that feed under water, like cetaceans, pinnipeds and marine turtles, are known to emit sound underwater, but such behaviour has not yet been described in seabirds. We aimed to assess the potential prevalence and diversity of vocalisations emitted underwater by penguins. We chose three study species from three different genera, and equipped foraging adults with video cameras with built-in microphones. We recorded a total of 203 underwater vocalisation from all three species during 4 h 43 min of underwater footage. Vocalisations were very short in duration (0.06 s on average), with a frequency of maximum amplitude averaging 998 Hz, 1097 Hz and 680 Hz for King, Gentoo and Macaroni penguins, respectively. All vocalisations were emitted during feeding dives and more than 50% of them were directly associated with hunting behaviour, preceeded by an acceleration (by 2.2 s on average) and/or followed by a prey capture attempt (after 0.12 s on average). The function of these vocalisations remain speculative. Although it seems to be related to hunting behaviour, these novel observations warrant further investigation.

Predatory behaviour and prey-capture decision-making by the web-weaving spider Micrathena sagittata

2005 ◽  
Vol 83 (2) ◽  
pp. 268-273 ◽  
Author(s):  
Francisco Díaz-Fleischer
Keyword(s):  
Prey Item ◽  
Prey Capture ◽  
Prey Size ◽  
Prey Type ◽  
Optimal Foraging Theory ◽  
Choice Test ◽  
Large Prey ◽  
Predatory Behaviour ◽  
Hunting Behaviour ◽  
The Web

Optimal-foraging theory predicts how a predator would feed most efficiently when faced with a choice of two types of prey differing in profitability and density in the habitat. The predator should focus only on the more profitable prey, since any prey item eaten by the predator has a cost in terms of the time and resources taken to subdue and eat it. A study of the hunting behaviour and prey-type selection of the web-weaving spider Micrathena sagittata (Walckenaer, 1841) (Araneae: Araneidae) in the field is documented. In the first part of the study, prey of two sizes were offered in four sectors of the web (top, bottom, right, and left). A prey item was provided at one position of the web at a time. Attack time was recorded at each position. Also, choice and no-choice tests were carried out by offering prey in opposing web sectors (top and bottom) simultaneously. Large prey were more successfully captured in the upper parts than in the bottom parts of the web. In the choice test, spiders always preferred large prey to small prey, while in the no-choice test, spiders always responded to the first stimulus received. Two different attack strategies, depending on prey size, were observed. Hunting strategies and prey-size preference can be related to the cost of web construction and profitability of the prey type.

Dominance determines fish community biomass in a temperate seagrass ecosystem

2019 ◽  
Author(s):  
Aaron Matthius Eger ◽  
Rebecca J. Best ◽  
Julia Kathleen Baum
Keyword(s):  
Species Richness ◽  
Ecosystem Function ◽  
Fish Community ◽  
Prey Capture ◽  
Fish Communities ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Community Biomass ◽  
Ecosystem Valuation ◽  
Species Abundances

Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combined surveys of natural fish communities (conducted in July and August, 2016) with morphological trait data to examine relationships between diversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54° N 130° W). We employed both taxonomic and functional trait measures of diversity to investigate if ecosystem function is driven by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we found that fish community biomass is maximized when taxonomic richness and functional evenness is low, and in communities dominated by species with particular trait values – those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.

Kalahari Cheetahs

2017 ◽  
Author(s):  
Gus Mills ◽  
Margaret Mills
Keyword(s):  
Reproductive Success ◽  
Spatial Ecology ◽  
Prey Selection ◽  
Arid Ecosystems ◽  
Foraging Success ◽  
Ecological Processes ◽  
Demographic Groups ◽  
Important Prey ◽  
Hunting Behaviour ◽  
The Impact

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.

scholarly journals Extensive Variation in the Activities of Pseudocerastes and Eristicophis Viper Venoms Suggests Divergent Envenoming Strategies Are Used for Prey Capture

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 112
Author(s):  
Bianca op den Brouw ◽  
Francisco C. P. Coimbra ◽  
Lachlan A. Bourke ◽  
Tam Minh Huynh ◽  
Danielle H. W. Vlecken ◽  
...  
Keyword(s):  
Prey Capture ◽  
Anticoagulant Activity ◽  
Protein Composition ◽  
Coagulation Factors ◽  
Arid Environments ◽  
Factor X ◽  
Venom Protein ◽  
Research Attention ◽  
Future Assessment ◽  
Viper Venoms

Snakes of the genera Pseudocerastes and Eristicophis (Viperidae: Viperinae) are known as the desert vipers due to their association with the arid environments of the Middle East. These species have received limited research attention and little is known about their venom or ecology. In this study, a comprehensive analysis of desert viper venoms was conducted by visualising the venom proteomes via gel electrophoresis and assessing the crude venoms for their cytotoxic, haemotoxic, and neurotoxic properties. Plasmas sourced from human, toad, and chicken were used as models to assess possible prey-linked venom activity. The venoms demonstrated substantial divergence in composition and bioactivity across all experiments. Pseudocerastes urarachnoides venom activated human coagulation factors X and prothrombin and demonstrated potent procoagulant activity in human, toad, and chicken plasmas, in stark contrast to the potent neurotoxic venom of P. fieldi. The venom of E. macmahonii also induced coagulation, though this did not appear to be via the activation of factor X or prothrombin. The coagulant properties of P. fieldi and P. persicus venoms varied among plasmas, demonstrating strong anticoagulant activity in the amphibian and human plasmas but no significant effect in that of bird. This is conjectured to reflect prey-specific toxin activity, though further ecological studies are required to confirm any dietary associations. This study reinforces the notion that phylogenetic relatedness of snakes cannot readily predict venom protein composition or function. The significant venom variation between these species raises serious concerns regarding antivenom paraspecificity. Future assessment of antivenom is crucial.

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