scholarly journals A unique feeding strategy of the extinct marine mammal Kolponomos : convergence on sabretooths and sea otters

2016 ◽  
Vol 283 (1826) ◽  
pp. 20160044 ◽  
Author(s):  
Z. Jack Tseng ◽  
Camille Grohé ◽  
John J. Flynn
Keyword(s):  
Prey Capture ◽  
Driving Forces ◽  
Feeding Strategy ◽  
Structural Stiffness ◽  
Sea Otters ◽  
Form Function ◽  
Masticatory Biomechanics ◽  
Prey Killing ◽  
Head Flexion ◽  
Shape Analyses

Mammalian molluscivores feed mainly by shell-crushing or suction-feeding. The extinct marine arctoid, Kolponomos , has been interpreted as an otter-like shell-crusher based on similar dentitions. However, neither the masticatory biomechanics of the shell-crushing adaptation nor the way Kolponomos may have captured hard-shelled prey have been tested. Based on mandibular symphyseal morphology shared by Kolponomos and sabre-toothed carnivores, we hypothesize a sabretooth-like mechanism for Kolponomos prey-capture, whereby the mandible functioned as an anchor. Torque generated from jaw closure and head flexion was used to dislodge prey by prying, with prey then crushed using cheek teeth. We test this hypothesized feeding sequence using phylogenetically informed biomechanical simulations and shape analyses, and find a strongly supported, shared high mandibular stiffness in simulated prey-capture bites and mandibular shape in Kolponomos and the sabre-toothed cat Smilodon . These two distantly related taxa converged on using mandibles to anchor cranial torqueing forces when prying substrate-bound prey in the former and sabre-driving forces during prey-killing in the latter. Simulated prey-crushing bites indicate that Kolponomos and sea otters exhibit alternative structural stiffness-bite efficiency combinations in mandibular biomechanical adaptation for shell-crushing. This unique feeding system of Kolponomos exemplifies a mosaic of form-function convergence relative to other Carnivora.

scholarly journals Quantitative Analysis of Lysobacter Predation

2015 ◽  
Vol 81 (20) ◽  
pp. 7098-7105 ◽  
Author(s):  
Ivana Seccareccia ◽  
Christian Kost ◽  
Markus Nett
Keyword(s):  
Experimental Data ◽  
Feeding Strategy ◽  
Predatory Behavior ◽  
Bacterial Group ◽  
Potential Prey ◽  
Bacterial Populations ◽  
Content Type ◽  
Predator Prey ◽  
Prey Killing ◽  
Predatory Potential

ABSTRACTBacteria of the genusLysobacterare considered to be facultative predators that use a feeding strategy similar to that of myxobacteria. Experimental data supporting this assumption, however, are scarce. Therefore, the predatory activities of threeLysobacterspecies were tested in the prey spot plate assay and in the lawn predation assay, which are commonly used to analyze myxobacterial predation. Surprisingly, only one of the testedLysobacterspecies showed predatory behavior in the two assays. This result suggested that not allLysobacterstrains are predatory or, alternatively, that the assays were not appropriate for determining the predatory potential of this bacterial group. To differentiate between the two scenarios, predation was tested in a CFU-based bioassay. For this purpose, defined numbers ofLysobactercells were mixed together with potential prey bacteria featuring phenotypic markers, such as distinctive pigmentation or antibiotic resistance. After 24 h, cocultivated cells were streaked out on agar plates and sizes of bacterial populations were individually determined by counting the respective colonies. Using the CFU-based predation assay, we observed thatLysobacterspp. strongly antagonized other bacteria under nutrient-deficient conditions. Simultaneously, theLysobacterpopulation was increasing, which together with the killing of the cocultured bacteria indicated predation. Variation of the predator/prey ratio revealed that all threeLysobacterspecies tested needed to outnumber their prey for efficient predation, suggesting that they exclusively practiced group predation. In summary, the CFU-based predation assay not only enabled the quantification of prey killing and consumption byLysobacterspp. but also provided insights into their mode of predation.

scholarly journals First evidence of prey capture and meat eating by wild Yunnan snub-nosed monkeys Rhinopithecus bieti in Yunnan, China

2010 ◽  
Vol 56 (2) ◽  
pp. 227-231 ◽  
Author(s):  
Baoping Ren ◽  
Dayong Li ◽  
Zhijin Liu ◽  
Baoguo Li ◽  
Fuwen Wei ◽  
...  
Keyword(s):  
Nonhuman Primates ◽  
Prey Capture ◽  
Dietary Diversity ◽  
Group Structure ◽  
Feeding Strategy ◽  
Rhinopithecus Bieti ◽  
Spatial Spread ◽  
Meat Eating ◽  
Begging Behavior ◽  
Animal Consumption

Abstract Most extant nonhuman primates occasionally prey on fast-moving, warm-blooded animals; however, Indriidae, Lepilemuridae, and Colobinae either scavenged for meat or did not eat meat at all. Here we report six cases of animal consumption by the snub-nosed monkey Rhinopithecus bieti in a wild, habituated group between 2004 and 2009 in Yunnan, China. At present, only males in an all-male unit within the study group were involved in active hunting. Such a male-biased activity may be related to the group structure and spatial spread of R. bieti. Two females were observed eating freshly killed birds. The findings confirmed that R. bieti engaged in scavenging and, when hunting, employed a cranio-cervical bite to kill their prey. Meat eating is likely a nutrient maximization feeding strategy in R. bieti, especially in males. A begging behavior occurred after successful prey capture. Although begging was observed, no sharing of the meat was seen. The present findings illuminate the dietary diversity of R. bieti and their ability to expand their dietary spectrum.

scholarly journals Ontogenetic Changes of the Aquatic Food Uptake Mode in the Danube Crested Newt (Triturus dobrogicus Kiritzescu 1903)

2021 ◽  
Vol 9 ◽  
Author(s):  
Nikolay Natchev ◽  
Kristina Yordanova ◽  
Sebastian Topliceanu ◽  
Teodora Koynova ◽  
Dimitar Doichev ◽  
...  
Keyword(s):  
Prey Capture ◽  
Feeding Strategy ◽  
Body Movement ◽  
Evolutionary Development ◽  
Integrative Approach ◽  
Feeding Apparatus ◽  
Locomotor System ◽  
Locomotor Apparatus ◽  
Food Uptake ◽  
Crested Newt

The study of the feeding mechanisms in vertebrates requires an integrative approach since the feeding event consists of a chain of behaviors. In the present study we investigated the food uptake behavior in different ontogenetic stages in the Danube crested newt (Triturus dobrogicus). We focused on the coordination in the kinematics of the elements of the locomotor and the feeding systems at the transition between the approach of the newt to the prey and the food uptake start. In the feeding strategy of the larvae of T. dobrogicus, the phase of food search is replaced by an initial “food detection phase.” In both larvae and adult specimens, the animals approached the food to a close distance by a precise positioning of the snout besides the food item. The larvae were able to reach food items offered at over 80° relative to the longitudinal midline of the head. When the food was offered at a large distance or laterally, the food uptake was either not successful or the coordination chain at the transition between food approach and food uptake was interrupted. In young larvae we detected an abrupt change in the activity of the locomotor system and the feeding system. The larvae approached the food by tail undulation and after reaching the final position of attack, no further activity of the locomotor apparatus was detectable. The larvae used a pure form of inertial suction to ingest food. In pre-metamorphic larvae and adults we registered an integrated activation of the locomotor apparatus (both limbs and tail) and the feeding apparatus during prey capture in the form of compensatory suction. The drastic change in the feeding mode of the pre-metamorphotic larvae and the adults compared to the younger larvae in T. dobrogicus may indicate the evolutionary development of a defined relation in the activity of the locomotor system and the control of the feeding apparatus. We propose that in newts, the interaction between the control execution in both systems switched from successive (body movement – feeding) into integrated (body movement – body movement and feeding) during the ontogeny. The main trigger for such a switch (at least in T. dobrogicus) is the formation of functional limbs during the late larval development.

Functional morphology and feeding strategy of the hydrothermal-vent polychaete Archinome rosacea (family Archinomidae)

2003 ◽  
Vol 81 (4) ◽  
pp. 582-590 ◽  
Author(s):  
Megan E Ward ◽  
Cheryl D Jenkins ◽  
Cindy Lee Man Dover
Keyword(s):  
Hydrothermal Vent ◽  
Trophic Ecology ◽  
Prey Capture ◽  
Feeding Strategy ◽  
Gut Content ◽  
Large Component ◽  
Feeding Mode ◽  
Morphological Studies ◽  
Toxic Materials ◽  
Content Analyses

Polychaetes are a large component of deep-sea hydrothermal-vent invertebrate faunas, yet little is known about the trophic ecology of most species. In this study, the feeding mode of a common and widespread vent polychaete, Archinome rosacea (order Amphinomida), is investigated through morphological studies and gut-content analyses. The foregut of this polychaete is similar in structure to that of other shallow-water Amphinomida. Prey capture is facilitated by a ventral muscular eversible proboscis with two glandular lateral-lip structures. Extracellular digestion is suggested by packets of digestive enzymes observed to be discharged from the apical ends of the midgut epithelial cells into the lumen. Midgut tissues also contain inclusions resembling spherocrystals, possibly sites where toxic materials are sequestered. Gut-content analyses indicate a preference for mobile prey, including polychaetes and crustaceans. We propose that predation and scavenging are important trophic strategies for A. rosacea.

scholarly journals Testing Darwin’s hypothesis about the most wonderful plant in the world: The Venus flytrap’s marginal spikes are a ‘horrid prison’ for moderate-sized insect prey

2018 ◽  
Author(s):  
Alexander L. Davis ◽  
Matthew H. Babb ◽  
Brandon T. Lee ◽  
Christopher H. Martin
Keyword(s):  
Prey Capture ◽  
Feeding Strategy ◽  
Adaptive Landscape ◽  
Large Prey ◽  
Capture Success ◽  
Dionaea Muscipula ◽  
Lab Experiments ◽  
Morphological Adaptations ◽  
The World ◽  
Laboratory Results

AbstractBotanical carnivory is a novel feeding strategy associated with numerous physiological and morphological adaptations. However, the benefits of these novel carnivorous traits are rarely tested. Here, we used field observations and lab experiments to test the prey capture function of the marginal spikes on snap traps of the Venus flytrap (Dionaea muscipula). Our field and laboratory results suggested surprisingly inefficient capture success: fewer than 1 in 4 prey encounters led to prey capture. Removing the marginal spikes decreased the rate of prey capture success for moderate-sized cricket prey by 90%, but this effect disappeared for larger prey. The nonlinear benefit of spikes suggests that they provide a better cage for capturing more abundant insects of moderate and small sizes, but may also provide a foothold for rare large prey to escape. Our observations support Darwin’s hypothesis that the marginal spikes form a ‘horrid prison’ that increases prey capture success for moderate-sized prey, but the decreasing benefit for larger prey is unexpected and previously undocumented. Thus, we find surprising complexity in the adaptive landscape for one of the most wonderful evolutionary innovations among all plants. These findings further enrich our understanding of the evolution and diversification of novel trap morphology in carnivorous plants.

scholarly journals Marine Protection Induces Morphological Variation in the California Moray, Gymnothorax mordax

2020 ◽  
Vol 60 (2) ◽  
pp. 522-534
Author(s):  
Rita S Mehta ◽  
Katherine E Dale ◽  
Benjamin A Higgins
Keyword(s):  
Local Community ◽  
Prey Capture ◽  
Feeding Habits ◽  
Feeding Strategy ◽  
Marine Conservation ◽  
Large Prey ◽  
Community Interactions ◽  
Conservation Area ◽  
Adductor Muscles ◽  
Insight Into

Synopsis The effectiveness of marine protected areas (MPAs) on the general health and conservation of species, habitats, and community interactions is of great interest to researchers, managers, and recreationalists. However, the ecological and behavioral diversity of vertebrate predators of southern California kelp forests limits our ability to make general conclusions about MPA effectiveness across a variety of species. Identifying and studying species with extreme feeding habits or prey-capture strategies may offer greater insight into predator–prey relationships and reveal the trophic importance of an animal in the larger community. Moray eels (family Muraenidae) have been shown to have morphological and behavioral adaptations that allow them to consume large prey whole, identifying them as important predators. From 2015 to 2018, we studied the health and feeding behavior of a long-lived, elusive, and benthic kelp forest predator, the California moray eel (Gymnothorax mordax). We trapped eels inside and outside of Blue Cavern Onshore State Marine Conservation Area, an MPA on the northwest side of Santa Catalina Island, CA which prohibits the take of any species. Over 4 years, we captured 1736 eels. Overall, we found that morays were longer, older, heavier, had higher body condition, and were found in greater abundance within the MPA. Although fish comprised the majority of their summer diet, morays outside of the MPA were consuming a more diverse set of fish, while kelp bass comprised more than half of the diet for morays inhabiting the MPA. Additionally, we found that morays within the MPA had larger relative vertical gape distances (VGDs) and narrower heads. Our recapture data support the high site fidelity of morays, indicating that their diet and morphology are influenced by their local community. While the majority of morays are thriving in the MPA, as suggested by their robust sizes and longevity, high abundance appears to result in higher frequencies of cannibalism, the presence of an undescribed disease, and lower growth rates. Our results suggest that the MPA affects the life history of morays and may select for an alternative feeding strategy in which eels develop larger VGDs, smaller adductor muscles, and a specialized diet which is presumably influenced by the local environment. In addition, observations of cannibalistic behavior and species-specific disease provide us with important insight into natural factors that may still regulate populations removed from anthropogenic disturbances such as fishing.

scholarly journals Polyp expansion of passive suspension feeders: a red coral case study

2019 ◽  
Author(s):  
Sergio Rossi ◽  
Lucia Rizzo ◽  
Jean-Claude Duchêne
Keyword(s):  
Water Temperature ◽  
Laboratory Experiments ◽  
Prey Capture ◽  
Driving Forces ◽  
Water Movement ◽  
Flow Speed ◽  
Current Speed ◽  
Passive Suspension ◽  
Suspension Feeders ◽  
Biological Variables

Polyp activity in passive suspension feeders has been linked to several environmental factors such as hydrodynamics, water temperature and food concentration. To better elucidate the driving forces controlling polyp expansion in these organisms and the potential role of particle concentration, the octocoral Corallium rubrum was investigated in accordance with two approaches: 1) High-frequency in-situ observations testing various environmental and biological variables affecting the water column, and 2) Video-recorded flume-controlled laboratory experiments performed under a range of environmental and biological conditions in terms of water temperature, flow speed, chemical signals and zooplankton. In the field, C. rubrum polyp activity correlated positively with particle (seston and zooplankton) concentration, which was related to current speed. This observation was confirmed by the flume video records of the laboratory experiments, which showed differences in polyp activity due to changes in temperature and current speed, but especially in response to nutritional stimuli and the presence of zooplankton. Zooplankton and water movement appeared to be the main factors controlling polyp expansion. These results suggest that the energy budget of passive suspension feeders (and probably the benthic community as a whole) may rely on their ability to maximise prey capture during food pulses. The latter, which may be described as discontinuous organic matter (dead or alive) input, may be the key to a better understanding of benthic-pelagic coupling processes and trophic impacts on animal forests composed of sessile suspension feeders.

scholarly journals Polyp expansion of passive suspension feeders: a red coral case study

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7076 ◽  
Author(s):  
Sergio Rossi ◽  
Lucia Rizzo ◽  
Jean-Claude Duchêne
Keyword(s):  
Water Temperature ◽  
Laboratory Experiments ◽  
Prey Capture ◽  
Driving Forces ◽  
Water Movement ◽  
Maximum Activity ◽  
Current Speed ◽  
Passive Suspension ◽  
Suspension Feeders ◽  
Biological Variables

Polyp activity in passive suspension feeders has been considered to be affected by several environmental factors such as hydrodynamics, water temperature and food concentration. To better elucidate the driving forces controlling polyp expansion in these organisms and the potential role of particle concentration, the octocoral Corallium rubrum was investigated in accordance with two approaches: (1) high-frequency in-situ observations examining various environmental and biological variables affecting the water column, and (2) video-recorded flume-controlled laboratory experiments performed under a range of environmental and biological conditions, in terms of water temperature, flow speed, chemical signals and zooplankton. In the field, C. rubrum polyp expansion correlated positively with particle (seston and zooplankton) concentration and current speed. This observation was confirmed by the flume video records of the laboratory experiments, which showed differences in polyp activity due to changes in temperature and current speed, but especially in response to increasing nutritional stimuli. The maximum activity was observed at the highest level of nutritional stimulus consisting of zooplankton. Zooplankton and water movement appeared to be the main factors controlling polyp expansion. These results suggest that the energy budget of passive suspension feeders (and probably the benthic community as a whole) may rely on their ability to maximise prey capture during food pulses. The latter, which may be described as discontinuous organic matter (dead or alive) input, may be the key to a better understanding of benthic-pelagic coupling processes and trophic impacts on animal forests composed of sessile suspension feeders.

scholarly journals Polyp expansion of passive suspension feeders: a red coral case study

2019 ◽  
Author(s):  
Sergio Rossi ◽  
Lucia Rizzo ◽  
Jean-Claude Duchêne
Keyword(s):  
Water Temperature ◽  
Laboratory Experiments ◽  
Prey Capture ◽  
Driving Forces ◽  
Water Movement ◽  
Flow Speed ◽  
Current Speed ◽  
Passive Suspension ◽  
Suspension Feeders ◽  
Biological Variables

Polyp activity in passive suspension feeders has been linked to several environmental factors such as hydrodynamics, water temperature and food concentration. To better elucidate the driving forces controlling polyp expansion in these organisms and the potential role of particle concentration, the octocoral Corallium rubrum was investigated in accordance with two approaches: 1) High-frequency in-situ observations testing various environmental and biological variables affecting the water column, and 2) Video-recorded flume-controlled laboratory experiments performed under a range of environmental and biological conditions in terms of water temperature, flow speed, chemical signals and zooplankton. In the field, C. rubrum polyp activity correlated positively with particle (seston and zooplankton) concentration, which was related to current speed. This observation was confirmed by the flume video records of the laboratory experiments, which showed differences in polyp activity due to changes in temperature and current speed, but especially in response to nutritional stimuli and the presence of zooplankton. Zooplankton and water movement appeared to be the main factors controlling polyp expansion. These results suggest that the energy budget of passive suspension feeders (and probably the benthic community as a whole) may rely on their ability to maximise prey capture during food pulses. The latter, which may be described as discontinuous organic matter (dead or alive) input, may be the key to a better understanding of benthic-pelagic coupling processes and trophic impacts on animal forests composed of sessile suspension feeders.

scholarly journals Research on the Structural Rigidity Characteristics of a Reconfigurable TBM Thrust Mechanism

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Younan Xu ◽  
Xinjun Liu ◽  
Jiyu Xu
Keyword(s):  
Driving Forces ◽  
Structural Parameters ◽  
Hydraulic Cylinder ◽  
Structural Stiffness ◽  
Factors Affecting ◽  
Structural Rigidity ◽  
Performance Indexes ◽  
Hydraulic Cylinders ◽  
Working Status ◽  
Type V

AbstractTo improve the adaptability of TBMs in diverse geological environments, this paper proposes a reconfigurable Type-V thrust mechanism (V-TM) with rearrangeable working states, in which structural stiffness can be automatically altered during operation. Therefore, millions of configurations can be obtained, and thousands of instances of working status per configuration can be set respectively. Nonetheless, the complexity of configurations and diversity of working states contributes to further complications for the structural stiffness algorithm. This results in challenges such as difficulty calculating the payload compliance index and the environment adaptability index. To solve this problem, we use the configuration matrix to describe the relationship between propelling jacks under reconfiguration and adopt pattern vectors to describe the working state of each hydraulic cylinder. Then, both the dynamic compatible equation between propeller forces of the hydraulic cylinders and driving forces, and the kinematic harmonizing equation between the hydraulic cylinder displacements and their deformations are established. Next, we derive the stiffness analytical equation using Hooke’s law and the Jacobian Matrix. The proposed approach provides an effective algorithm to support structural rigidity analysis, and lays a solid theoretical foundation for calculating the performance indexes of the V-TM. We then analyze the rigidity characteristics of typical configurations under different working states, and obtain the main factors affecting structural stiffness of the V-TM. The results show the deviation degree of structural parameters in hydraulic cylinders within the same group, and the working status of propelling jacks. Finally, our constructive conclusions contribute valuable information for matching and optimization by drawing on the factors that affect the structural rigidity of the V-TM.

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