The Effects of Satiation on Strike Mode and Prey Capture Kinematics in the Largemouth bass, Micropterus salmoides

The feeding mechanism and kinematics of prey capture have been studied in many fishes. However, the effects of satiation on the strike mode and prey capture kinematics have never been directly measured. We analyze 12 kinematic variables to determine the effects of satiation on prey capture in five largemouth bass, Micropterus salmoides, by using high speed videography. We also present the first experimental test for modulatory capabilities in response to satiation, by using the ram-suction index. Significant changes in the kinematic variables of maximum lower jaw depression, maximum gape distance, maximum hyoid depression, time to maximum hyoid depression, and time from maximum hyoid depression to recovery were seen with the effects of satiation. Change in the kinematic variables imply a decrease in jaw opening velocity and the magnitude of suction velocity created during repetitive strikes by M. salmoides with increasing satiation. The bass primarily uses a ram strike mode, with some suction bites occasionally. Ram-suction index analyses suggests that M. salmoides does not modulate strike mode in response to satiation. However, the bass modulate prey capture kinematics without altering strike mode with the effects of satiation. Prey capture success decreases in each bass, as the probability of a successful prey capture event becomes lower, with increasing satiation. These findings demonstrate that satiation can have major effects on prey capture kinematics and future studies of feeding kinematics should account for satiation in their analyses.     

Trap‐jaws revisited: the mandible mechanism of the ant Acanthognathus

Abstract.Ants of the genus Acanthognathus stalk small insects and catch their prey by a strike with their long, thin mandibles. The mandibles close in less than 2.5 ms and this movement is controlled by a specialized closer muscle. In Acanthognathus , unlike other insects, the mandible closer muscle is subdivided into two distinct parts: as in a catapult, a large slow closer muscle contracts in advance and provides the power for the strike while the mandibles are locked open. When the prey touches specialized trigger hairs, a small fast closer muscle rapidly unlocks the mandibles and thus releases the strike. The fast movement is steadied by large specialized surfaces in the mandible joint and the sensory‐motor reflex is controlled by neurones with particularly large, and thus fast‐conducting, axons.     

Comparisons of aquatic versus terrestrial predatory strikes in the pitviper, Agkistrodon piscivorus

Recent studies comparing terrestrial versus aquatic locomotion in animals have shown that changes in kinematics, muscular activation patterns, and performance across media are often dramatic. Surprisingly, however, despite the importance of feeding to the survival of most animals, few studies have compared differences in feeding behaviour between media. The present study compares prey-capture behaviour, strike success, strike velocity and acceleration, and prey-capture kinematics in a semi-aquatic pitviper (Agkistrodon piscivorus) when capturing both terrestrial (mice) and aquatic (fish) prey in a standardized laboratory setting. Strike velocity and acceleration did not differ significantly between media, but instead were positively correlated with initial prey distance. By contrast, the kinematics of terrestrial and aquatic strikes differed significantly in several aspects: max gape angle during the retraction phase, angular velocity of mouth closing during the strike, and the initial head angle before the strike. Terrestrial strikes were associated with higher gape angles during the retraction phase, higher angular velocities of mouth closure, and a more inclined head angle at the onset of the strike. Finally, strike success differed significantly between strike types, with terrestrial strikes being considerably more successful than aquatic strikes. Strike success likely differed due to the relatively slow mouth-closing velocity of aquatic strikes.     

Modulation and variability of prey capture kinematics in clariid catfishes

Species with narrow or limited diets (trophic specialists) are expected to be less flexible in their feeding repertoire compared to species feeding on a wide range of different prey (trophic generalists). The ability to modulate prey capture kinematics in response to different prey types and prey position, as well as the overall variability in prey capture kinematics, is evaluated in four clariid species ranging from trophic generalist (Clarias gariepinus) to species with morphological specializations and a narrow diet (Channallabes apus and Gymnallabes typus). High-speed video recordings were made of prey captures on two prey that differ in shape, attachment strength and hardness. While the observed amount of strike-to-strike variability in prey capture kinematics is similar for all species and not influenced by prey type, only the two less specialized species showed the ability to modulate their prey capture kinematics in function of the presented prey types. All species did, however, show positional modulation during the strike by adjusting the magnitude of neurocranial elevation. These results indicate that the narrow dietary breadth of trophic specialists is indeed indicative of functional stereotypy in this group of fishes. Although most studies focussing on prey processing found a similar result, the present study is one of the few that was able to demonstrate this relationship when focussing on prey capture mechanics. Possibly, this relationship is less frequently observed for prey capture compared to prey processing because, regardless of prey type, the initial capture of prey requires a higher amount of variability.     

Mandible strike: the lethal weapon of Odontomachus opaciventris against small prey

In order to study both the hunting efficiency and the flexibility of their predatory behavior, solitary hunters of the trap-jaw ant Odontomachus opaciventris were offered small prey (termites, fruit flies and tenebrionid larvae), presenting different morphological or defensive characteristics. The monomorphic hunters showed a moderately flexible predatory behavior characterized by short capture sequences and a noteworthy efficiency of their mandible strike (76.7-100% of prey retrievals), even when presented with Nasutitermes soldiers. Contrary to most poneromorph ants, antennal palpation of the prey before the attack was always missing, no particular targeted region of the prey's body was preferred, and no 'prudent' posture was ever exhibited. Moreover, stinging was regularly performed on bulky, fast moving fruit flies, very scarcely with sclerotized tenebrionid larvae, but never occurred with Nasutitermes workers or soldiers despite their noxious chemical defense. These results suggest that, whatever the risk linked to potentially dangerous prey, O. opaciventris predatory strategy optimizes venom use giving top priority to the swiftness and strength of the lethal trap-jaw system used by hunters as first strike weapon to subdue rapidly a variety of small prey, ranging from 0.3 to 2 times their own body size and from 0.1 to 2 times their weight. Such risk-prone predatory behavior is likely to be related to the large size of O. opaciventris colonies where the death of a forager might be of lesser vital outcome than in small colony-size species.     

The effects of intraspecific competition on the prey capture behavior and kinematics of the bluegill sunfish, Lepomis macrochirus

Competition has broad effects on fish and specifically the effects of competition on the prey capture kinematics and behavior are important for the assessment of future prey capture studies in bony fishes. Prey capture kinematics and behavior in bony fishes have been shown to be affected by temperature and satiation. The densities at which bony fish are kept have also been shown to affect their growth, behavior, prey selection, feeding and physiology. We investigated how density induced intraspecific competition for food affects the prey capture kinematics of juvenile bluegill sunfish, Lepomis macrochirus. High speed video was utilized to film five bold individuals feeding at three different densities representing different levels of intraspecific competition. We hypothesized that: (1) the feeding kinematics will be faster at higher levels of competition compared to lower levels of competition, and (2) bluegill should shift from more suction-based feeding towards more ram-based feeding with increasing levels of competition in order to outcompete conspecifics for a prey item. We found that, with increased intraspecific competition, prey capture became faster, involving more rapid jaw opening and therefore greater inertial suction, shorter mouth closing times, and shorter gape cycles. Furthermore, the attack velocity of the fish increased with increasing competition, however a shift towards primarily ram based feeding was not confirmed. Our study demonstrates that prey capture kinematics are affected by the presence of conspecifics and future studies need to consider the effects of competition on prey capture kinematics.     

Modulation of prey capture kinematics and the role of lingual sensory feedback in the lizard Pogona vitticeps

Most organisms feed on a variety of prey that may differ dramatically in their physical and behavioural characteristics (e.g. mobility, mass, texture, etc.). Thus the ability to modulate prey capture behaviour in accordance with the characteristics of the food appears crucial. In animals that use rapid tongue movements to capture prey (frogs and chameleons), the coordination of jaws and tongue is based on visual cues gathered prior to the prey capture event. However, most iguanian lizards have much slower tongue-based prey capture systems suggesting that sensory feedback from the tongue may play an important role in coordinating jaw and tongue movements. We investigated the modulation of prey capture kinematics in the agamid lizard Pogona vitticeps when feeding on a range of food items differing in their physical characteristics. As the lizard is a dietary generalist, we expected it to be able to modulate its prey capture kinematics as a function of the (mechanical) demands imposed by the prey. Additionally, we investigated the role of lingual sensory feedback by transecting the trigeminal sensory afferents. Our findings demonstrated that P. vitticeps modulates its prey capture kinematics according to specific prey properties (e.g. size). In addition, transection of the trigeminal sensory nerves had a strong effect on prey capture kinematics. However, significant prey type effects and prey type by transection effects suggest that other sources of sensory information are also used to modulate the prey capture kinematics in P. vitticeps.     

Jaws that snap: control of mandible movements in the ant Mystrium

Ants of the genus Mystrium employ a peculiar snap-jaw mechanism in which the closed mandibles cross over to deliver a stunning blow to an adversary within about 0.5 ms. The mandible snapping is preceded by antennation and antennal withdrawal. The strike is initiated by contact of the adversary with mechanosensory hairs at the side of the mandible, and is powered by large yet slow closer muscles whose energy is stored by a catapult mechanism. Recording of closer muscle activity indicates that the mandibles are not triggered by any fast muscle. Instead, we suppose that activity differences between the left and right mandible muscles imbalance a pivot at the mandible tip and release the strike. The likelihood for the strike to occur can be modulated by an alarm pheromone. The presence of specialized sensilla and of a complex muscle receptor organ shows that the mandibles are also adapted to functions other than snapping and suggests that the force of the mandible can be finely adjusted for other tasks.     

Fin-tail coordination during escape and predatory behavior in larval zebrafish

Larval zebrafish innately perform a suite of behaviors that are tightly linked to their evolutionary past, notably escape from threatening stimuli and pursuit and capture of prey. These behaviors have been carefully examined in the past, but mostly with regard to the movements of the trunk and tail of the larvae. Here, we employ kinematics analyses to describe the movements of the pectoral fins during escape and predatory behavior. In accord with previous studies, we find roles for the pectoral fins in slow swimming and immediately after striking prey. We find novel roles for the pectoral fins in long-latency, but not in short-latency C-bends. We also observe fin movements that occur during orienting J-turns and S-starts that drive high-velocity predatory strikes. Finally, we find that the use of pectoral fins following a predatory strike is scaled to the velocity of the strike, supporting a role for the fins in braking. The implications of these results for central control of coordinated movements are discussed, and we hope that these results will provide baselines for future analyses of cross-body coordination using mutants, morphants, and transgenic approaches.     

The fast mandible strike in the trap-jaw ant Odontomachus

Ants of the ponerine genus Odontomachus employ a trap-jaw mechanism that allows them to instantaneously close their long, sturdy mandibles to catch prey or to defend themselves. Photoelectric scanning has revealed that these trap-jaws can be closed in less than 0.5 ms and that they decelerate before they collide with each other. The mandible strike is released in a reflexlike action when particular trigger hairs are touched. This reflex takes 4 to 10 ms and is probably the fastest reflex yet described for any animal. This speed is based on a catch mechanism in the mandible joint that keeps the extended mandibles open during contraction of the powerful closer muscle and allows the potential energy it produces to be stored within cuticular elements, apodemes, and the closer muscle itself. During a strike a relatively small specialized trigger muscle unlocks the catch, instantaneously releasing the stored energy to accelerate the mandible.     

Largemouth bass (Micropterus salmoides) switch feeding modalities in response to sensory deprivation

Animals use a suite of sensory modalities to precisely locate and capture prey. While numerous studies have examined the effects of sensory deprivation on the behaviors leading to prey capture and while it is generally believed that information in the pre-strike period determines the way fish capture prey, this study is the first to examine the contribution of sensory information to jaw kinematics during capture. Largemouth bass were filmed using high-speed videography while capturing live mosquitofish. Bass were examined intact, with visual deprivation under infrared light, and with lateral line deprivation following treatment with cobalt chloride. Deprived of visual cues, this visual ram-feeding predator switches towards suction-based feeding to successfully capture prey. They approach prey slowly but open their mouths more rapidly, which has been shown to result in greater buccal pressure, causing their prey to move a greater distance at a more rapid velocity as they are being drawn into the predators' mouths. Deprived of lateral line cues, bass have higher forward velocities during capture and capture prey earlier in the gape cycle. This study demonstrates that sensory pre-strike information directly affects the capture modality employed by fishes and that fish can modulate between ram and suction not only by adjusting the amount of ram by increasing or decreasing their movements, but also by actively increasing the amount of suction used. These results suggest that the ability to modulate feeding behavior may allow animals to not only exploit a broader breadth of prey items, but also to be capable of doing so in a wider variety of environments.     

Piscivorous cyprinid fish modulates suction feeding kinematics to capture elusive prey

Previous studies have shown that evasive prey generally elicit a different kinematical pattern of prey capture from suction feeding fish compared to non-evasive types of prey. However, no evidence exists that predatory fish can modulate their prey capture kinematics in response to whether or not an elusive prey performs an escape response. Here, we analyse prey capture kinematics of a specialist piscivore (asp, Aspius aspius) during feeding on untethered, live goldfish, which regularly displayed escape attempts when attacked by the asp. Significant modulation occurred in function of the escape attempts of prey: mouth opening was prolonged and increased in magnitude, and one individual also showed an increased hyoid depression when feeding on prey trying to escape. As the orientation of the prey with respect to the predator prior to the start of mouth opening was related to the probability of observing an escape attempt, asp could theoretically perform this type of modulation by a priori choosing a pre-programmed motor pattern. However, since contact between the prey and the asp's mouth appeared to be a factor improving the timing of mouth closing, this fine-tuning of prey capture kinematics is more likely to be caused by reflexive neural feedback control.     

Geographical variation in mandible morphologies specialised for collembolan predation depend on prey size in the ant Strumigenys lewisi

1. Ants in the genus Strumigenys are predator ants that feed on tiny soil arthropods. The mandibles are modified into high‐speed traps to capture swift collembolan prey. The peculiar mandible morphologies of these ants have evolved depending on characteristics of the prey. Specifically, the evolution of mandible size and shape may be directly driven by prey size. 2. In the present study, the intraspecific variation of the morphological traits of Strumigenys lewisi populations were observed in central Japan. The relationships between the morphological variations and the prey body size were analysed. 3. In workers and queens, three morphological traits, head width, mandible length, and mandible width were significantly different among the multiple sites. Specifically, the mandible length was shorter in southwestern Japan than in other sampling locations. The ancova model revealed that the allometry of the mandible length to the head width was different among the sites. 4. As predicted, the mandible length was positively correlated with the average body size of collembolans in the Entomobryidae family. Furthermore, multiple regression analysis showed that the variation of the mandible length was affected by environmental factors represented as location information. However, the effect of collembolan body size was more effective at predicting mandible length. The study suggests that the geographical variation of mandible morphologies in S. lewisi has been selected by predator–prey interactions with collembolans.     

Separating the effects of prey size and speed on the kinematics of prey capture in the omnivorous lizard Gerrhosaurus major

Feeding behavior is known to be modulated as prey properties change. During prey capture, external prey properties, including size and mobility, are likely some of the most important components in predator–prey interactions. Whereas prey size has been demonstrated to elicit modulation of jaw movements during capture, how prey speed affects the approach and capture of prey remains unknown. We quantified the kinematics associated with movements of both the feeding and locomotor systems during prey capture in a lizard, Gerrhosaurus major, while facing prey differing in size and mobility (newborn mice, grasshoppers, and mealworms). Our data show that the feeding and locomotor systems were recruited differently in response to changes in the size or speed of the prey. The timing of jaw movements and of the positioning of the head are affected by changes in prey size—and speed, to a lesser extent. Changes in prey speed resulted in concomitant changes in the speed of strike and an early and greater elevation of the neck. External prey properties, and prey mobility in particular, are relevant in predator–prey interactions and elicit specific responses in different functional systems.     

Modulation of prey capture kinematics in the cheeklined wrasse Oxycheilinus digrammus (Teleostei: Labridae)

The ability to modulate prey capture behaviors is of interest to organismal biologists as it suggests that predators can perceive features of the prey and select suitable behaviors from an available repertoire to successfully capture the item. Thus, behavior may be as important a trait as morphology in determining an organism's diet. Using high-speed video, we measured prey capture kinematics in three cheeklined wrasse, Oxycheilinus digrammus. We studied the effects of three experimental prey treatments: live fish, dead prawn suspended in the water column, and dead prawn pieces anchored to the substrate in a clip. Live prey elicited significantly more rapid strikes than dead prey suspended in the water column, and the head of the predator was expanded to significantly larger maxima. These changes in prey capture kinematics suggest the generation of more inertial suction. With greater expansion of the head, more water can be accelerated into the buccal cavity. The attached prey treatment elicited strikes as rapid as those on live prey. We suggest that the kinematics of rapid strikes on attached prey are indicative of attempts to use suction to detach the prey item. More rapid expansion of the buccal or mouth cavity should lead to higher velocities of water entering the mouth and therefore to enhanced suction. Further modulation in response to the attached prey item, such as clipping or wrenching behaviors, was not observed. J. Exp. Zool. 290:88-100, 2001.     

Predatory behavior in the genusLeptogenys: A comparative study

We studied the predatory behavior of seven species of the genusLeptogenys from Mexico and Cameroon. The ants of this genus are armed with long, thin, curved mandibles articulated at the extreme corners of the anterior margin of the head, permitting them easily to seize oniscoid isopods, the obligate or the principal prey of mostLeptogenys species. Workers hunt these prey, which are able to roll themselves up, solitarily. Foraging behavior comprises sequences of up to eight activities. The prey can be seized by the body (rolled up or not), or alternatively by the edge of the shell, then turned over and stung on the ventral face. A relationship between the mandible size of the workers and the handling method permitted us to established that the phase “seizure by the edge of the shell” (compared to grasping the prey by the body) was more frequent as the prey size increased or the mandible length of the workers decreased. The rate of prey escape followed the same pattern. When a prey escaped, workers reacted by using a local searching or “reserve” behavior: they moved by increasing both sinuosity and speed. Recruitment occurred mainly after a worker found a group of prey or a large prey.L. mexicana are attractive at a distance to the isopods Bathytropidae living in the same natural environment. As a consequence, prey capture is possible without foraging for this species.     

Functional morphology of bite mechanics in the great barracuda (Sphyraena barracuda)

The great barracuda, Sphyraena barracuda, is a voracious marine predator that captures fish with a swift ram feeding strike. While aspects of its ram feeding kinematics have been examined, an unexamined aspect of their feeding strategy is the bite mechanism used to process prey. Barracuda can attack fish larger than the gape of their jaws, and in order to swallow large prey, can sever their prey into pieces with powerful jaws replete with sharp cutting teeth. Our study examines the functional morphology and biomechanics of 'ram-biting' behavior in great barracuda where the posterior portions of the oral jaws are used to slice through prey. Using fresh fish and preserved museum specimens, we examined the jaw mechanism of an ontogenetic series of barracuda ranging from 20 g to 8.2 kg. Jaw functional morphology was described from dissections of fresh specimens and bite mechanics were determined from jaw morphometrics using the software MandibLever (v3.2). High-speed video of barracuda biting (1500 framess(-1)) revealed that prey are impacted at the corner of the mouth during capture in an orthogonal position where rapid repeated bites and short lateral headshakes result in cutting the prey in two. Predicted dynamic force output of the lower jaw nearly doubles from the tip to the corner of the mouth reaching as high as 58 N in large individuals. A robust palatine bone embedded with large dagger-like teeth opposes the mandible at the rear of the jaws providing for a scissor-like bite capable of shearing through the flesh and bone of its prey.     

Zooplankton capture by a coral reef fish: an adaptive response to evasive prey

Synopsis High-speed cinematography and video using modified Schlieren optics and laser illumination helped elicit details of prey capture mechanisms used by Chromis viridis while feeding on calanoid copepods and Artemia. Chromis viridis is capable of a ram-jaw, low-suction feeding, as well as a typical suction feeding behavior described for other species of planktivores. By adjusting the degree of jaw protrusion and amount of suction used during a feeding strike, this fish can modulate its feeding strikes according to the prey type being encountered. The ram-jaw feeding mode enables C. viridis to capture highly evasive calanoid copepods within 6 to 10 msec. The use of specialized feeding behavior for evasive prey and the ability to vary feeding behavior are adaptations for feeding on evasive prey.     

Effects of luminance, size, and angular velocity on the recognition of nonlocomotive prey models by the praying mantis

Adult females of the mantis Tenodera angustipennis were presented with the "nonlocomotive" prey model, a static rectangle with two lines oscillating regularly at its sides, generated on a computer display. The models were varied in rectangle luminance (black, gray, and light gray), rectangle height (0.72, 3.6, and 18 mm), rectangle width (0.72, 3.6, and 18 mm), and angular velocity of oscillating lines (65°, 260°, and 1040°/s) to examine their effects on prey recognition. Before striking the model, the mantis sometimes showed peering movements that involved swaying its body from side to side. The black model of medium size (both height and width) elicited higher rates of fixation, peering, and strike responses than the large, small, or gray model. The model of medium angular velocity elicited a higher strike rate than that of large or small angular velocity, but angular velocity had little effect on fixation and peering. We conclude that mantises respond to a rectangle in deciding whether to fixate, and to both rectangle and lines in deciding whether to strike after fixation. Received: September 2, 1999 / Accepted: March 21, 2000     

Kinematics Analyses Related to Stretch-Shortening Cycle during Soccer Instep Kicking After Different Acute Stretching

ABSTRACT: Amiri-Khorasani, M, MohammadKazemi, R, Sarafrazi, S, Riyahi-Malayeri, S, and Sotoodeh, V. Kinematics analyses related to stretch-shortening cycle during soccer instep kicking after different acute stretching. J Strength Cond Res 26(11): 3010-3017, 2012-The purpose of this study was to examine the effects of static and dynamic stretching within a preexercise warm-up on angular velocity of knee joint, deepest knee flexion (DKF), and duration of eccentric and concentric contractions, which are relative to the stretch-shortening cycle (SSC) during instep kicking in professional soccer players. The kicking motions of dominant legs were captured from 18 Olympic professional male soccer players (height: 180.38 ± 7.34 cm; weight: 69.77 ± 9.73 kg; age: 19.22 ± 1.83 years) using 4 digital video cameras at 50 Hz. There was a significant difference in the DKF after the dynamic stretching (-3.22 ± 3.10°) vs. static stretching (-0.18 ± 3.19°) relative to the no-stretching method with p < 0.001. Moreover, there was significant difference in eccentric duration after the dynamic stretching (0.006 ± 0.01 seconds) vs. static stretching (-0.003 ± 0.01 seconds) relative to the no-stretching method with p < 0.015. There was a significant difference in the concentric duration after the dynamic stretching (-0.007 ± 0.01 seconds) vs. static stretching (0.002 ± 0.01 seconds) relative to the no-stretching method with p < 0.001. There was also a significant difference in knee angular velocity after the dynamic stretching (4.08 ± 3.81 rad·s) vs. static stretching (-5.34 ± 4.40 rad·s) relative to the no-stretching method with p < 0.001. We concluded that dynamic stretching during warm-ups, as compared with static stretching, is probably the most effective way as preparation for the kinematics characteristics of soccer instep kick, which are relative to the SSC.