Quantitative analysis of feeding kinematics in dusky salamanders (Desmognathus)

1988 ◽  
Vol 66 (6) ◽  
pp. 1309-1317 ◽  
Author(s):  
John H. Larsen Jr. ◽  
John T. Beneski Jr.
Keyword(s):  
Quantitative Analysis ◽  
Prey Item ◽  
Prey Capture ◽  
Large Prey ◽  
Selective Force ◽  
Mandibular Symphysis ◽  
Lower Jaw ◽  
Feeding Kinematics

Gape formation by the dusky salamander (Desmognathus) involves both upper and lower jaws and occurs in a manner similar to that of other terrestrial salamanders. As Desmognathus opens its mouth, ventral rotation of the mandibles is restricted but not stopped by the atlas–mandibular ligaments; the lower jaw is not propelled anteriorly. Tongue protraction, well beyond the mandibular symphysis, is always a major component of prey capture by this genus. After the sticky tongue pad has made contact with the prey, the salamander's head surges forward and the pad is rapidly retracted with the prey item attached. Aided by a unique suite of characters the mouth then snaps shut with considerable force. Our study supports the premise that Desmognathus is no different from most, if not all, terrestrial salamanders in its employment of tongue projection as a major feature in prey capture. We argue that the primary selective force for the unique configuration of desmognathine cephalic structures was enhancement of the ability of these small salamanders to capture relatively large prey without an increase in the size of the head and body.

scholarly journals Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche

2019 ◽  
Author(s):  
Michelle E. St. John ◽  
Roi Holzman ◽  
Christopher H. Martin
Keyword(s):  
Surface Area ◽  
Ecological Niche ◽  
Prey Capture ◽  
F1 Hybrids ◽  
Obtuse Angle ◽  
F1 Hybrid ◽  
San Salvador ◽  
Lower Jaw ◽  
Foraging Preferences ◽  
Feeding Kinematics

AbstractThe origins of novel trophic specialization, in which organisms begin to exploit novel resources for the first time, may be explained by shifts in behavior such as foraging preferences or feeding kinematics. One way to investigate the behavioral mechanisms underlying ecological novelty is by comparing prey capture kinematics between groups. In this study, we investigated the contribution of kinematics to the origins of a novel ecological niche for scale-eating within a microendemic adaptive radiation of pupfishes on San Salvador Island, Bahamas. We compared prey capture kinematics across three species of pupfish while consuming shrimp and scales in the lab and found that scale-eating pupfish exhibited peak gape sizes that were twice as large as all other groups, but also attacked prey with a more obtuse angle between their lower jaw and suspensorium. We then investigated how this variation in feeding kinematics could explain scale-biting performance by measuring the surface area removed per strike from standardized gelatin cubes. We found that a combination of larger peak gape and more obtuse lower jaw and suspensorium angles resulted in 67% more surface area removed per strike, indicating that scale-eaters may reside on a performance optimum for scale-biting. We also measured feeding kinematics of F1 hybrids to test whether feeding performance could contribute to reproductive isolation between species and found that F1 hybrid kinematics and performance more closely resembled those of generalists, suggesting that they may have low fitness in the scale-eating niche. Ultimately, our results suggest that the evolution of strike kinematics in this radiation is an adaptation to the novel niche of scale-eating.

scholarly journals Scaling the feeding mechanism of largemouth bass (Micropterus salmoides): kinematics of prey capture

1995 ◽  
Vol 198 (2) ◽  
pp. 419-433 ◽  
Author(s):  
B Richard ◽  
P Wainwright
Keyword(s):  
Body Size ◽  
Largemouth Bass ◽  
High Speed ◽  
Time Course ◽  
Prey Capture ◽  
Micropterus Salmoides ◽  
Feeding Mechanism ◽  
Functional Changes ◽  
Lower Jaw ◽  
Feeding Kinematics

We present the first analysis of scaling effects on prey capture kinematics of a feeding vertebrate. The scaling of feeding kinematics of largemouth bass (Micropterus salmoides) was investigated using high-speed video (200 fields s-1) to determine what functional changes occur in the feeding mechanism as a consequence of body size. A size series of ten bass ranging from 32 to 210 mm standard length was used for the study and ten feeding sequences from each individual were analyzed to quantify movements of the feeding apparatus during prey capture. Maximal linear and angular displacements of the strike scaled isometrically. The time course of the strike was longer in larger fish. Maximal velocities of displacement were more rapid in larger fish, but their scaling exponents indicated that the intrinsic rate of muscle shortening decreased with fish size. Morphological measurements of the lever arms of the lower jaw and of the two major muscles that drive the feeding mechanism were made to relate possible biomechanical changes in the feeding mechanism to the observed kinematic relationships. The lever arms of the lower jaw and the muscles scaled isometrically; hence, the relative slowing of movements with increasing body size cannot be attributed to changes in mechanical advantage with change in body size. The scaling of feeding kinematics in the largemouth bass is in accord with the scaling of rates of muscle contraction found in other lower vertebrates. These findings demonstrate that body size can have major effects on feeding kinematics and that future comparative studies of feeding kinematics should use empirical data on size effects in kinematic comparisons between taxa.

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.

Functional implications of supercontracting muscle in the chameleon tongue retractors

2001 ◽  
Vol 204 (21) ◽  
pp. 3621-3627 ◽  
Author(s):  
Anthony Herrel ◽  
Jay J. Meyers ◽  
Peter Aerts ◽  
Kiisa C. Nishikawa
Keyword(s):  
Prey Capture ◽  
Three Dimensional ◽  
Force Production ◽  
Retractor Muscle ◽  
Muscle Physiology ◽  
Large Prey ◽  
Wide Range ◽  
Ambush Predators ◽  
Full Body

SUMMARYChameleons capture prey items using a ballistic tongue projection mechanism that is unique among lizards. During prey capture, the tongue can be projected up to two full body lengths and may extend up to 600 % of its resting length. Being ambush predators, chameleons eat infrequently and take relatively large prey. The extreme tongue elongation (sixfold) and the need to be able to retract fairly heavy prey at any given distance from the mouth are likely to place constraints on the tongue retractor muscles. The data examined here show that in vivo retractor force production is almost constant for a wide range of projection distances. An examination of muscle physiology and of the ultrastructure of the tongue retractor muscle shows that this is the result (i) of active hyoid retraction, (ii) of large muscle filament overlap at maximal tongue extension and (iii) of the supercontractile properties of the tongue retractor muscles. We suggest that the chameleon tongue retractor muscles may have evolved supercontractile properties to enable a substantial force to be produced over a wide range of tongue projection distances. This enables chameleons successfully to retract even large prey from a variety of distances in their complex three-dimensional habitat.

Variation in the feeding kinematics of mole salamanders (Ambystomatidae: Ambystoma)

1995 ◽  
Vol 73 (2) ◽  
pp. 353-366 ◽  
Author(s):  
John T. Beneski Jr. ◽  
John H. Larsen Jr. ◽  
Brian T. Miller
Keyword(s):  
Feeding Behavior ◽  
High Speed ◽  
Prey Capture ◽  
Mouth Opening ◽  
General Increase ◽  
Feeding Kinematics ◽  
High Speed Cinematography ◽  
Mode A ◽  
General Reduction

High-speed cinematography was used to investigate the prey-capture kinematics of six species of mole salamanders (Ambystomatidae). We compared the feeding behavior of the subgenus Ambystoma (A. californiense and A. macrodactylum) with that of the subgenus Linguaelapsus (A. mabeei, A. texanum, A. annulatum, and A. cingulatum). Prey capture by all six species is characterized by a 3-part gape cycle (a period of rapid mouth opening prior to extraoral tongue protraction, followed by a period of relatively stable gape angle during extraoral tongue protraction and retraction, followed by a period of rapid mouth closure), a tongue-extension cycle (protraction and retraction), and anterior head–body displacement. Among the six species, two distinct modes of prey capture are evident: (1) the Ambystoma mode (A. californiense, A. macrodactylum, A. mabeei, and A. texanum), and (2) the Linguaelapsus mode (A. annulatum and A. cingulatum). Most differences in prey-capture kinematics between the two modes are primarily differences of degree rather than the addition or loss of unique behaviors, and include a general reduction in the gape angles and a general increase in the elapsed times associated with specific events in the Linguaelapsus mode. We hypothesize that these differences are primarily the result of a prolonged period of tongue protraction in the Linguaelapsus mode during which the glandular tongue pad is fitted to the prey. In addition to differing from each other, the gape profiles of the ambystomatid subgenera differ markedly from the 4-part gape profiles of plethodontids and salamandrids.

scholarly journals How within-group behavioural variation and task efficiency enhance fitness in a social group

2010 ◽  
Vol 278 (1709) ◽  
pp. 1209-1215 ◽  
Author(s):  
Jonathan N. Pruitt ◽  
Susan E. Riechert
Keyword(s):  
Prey Capture ◽  
Common Garden ◽  
Division Of Labour ◽  
Large Prey ◽  
Task Specialization ◽  
Capture Success ◽  
Social Phenotype ◽  
Individual Task ◽  
Task Efficiency

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus , colony members exhibit a behavioural polymorphism; females either exhibit an aggressive ‘asocial’ or docile ‘social’ phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

The Inactivity of Animals: Influence of Stochasticity and Prey Size

Behaviour ◽  
1985 ◽  
Vol 92 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
Dorian Moss ◽  
William J. Sutherland
Keyword(s):  
Food Supply ◽  
Prey Capture ◽  
Prey Size ◽  
Large Prey ◽  
Small Prey ◽  
Sufficient Food

As a consequence of prey capture being partly dependent upon chance, each individual may usually spend much of the day inactive even if the population is limited by its food supply. This applies particularly to species that eat large prey and thus experience considerable day-to-day variation in intake which restricts them to relatively rich habitats. Food will be found easily on most days and little time need be spent hunting although, occasionally, they will be unlucky and, despite searching all day, risk starvation. Predators of small prey can survive in environments that provide barely sufficient food as they experience little variation in intake: but they need to search all day to sustain themselves.

Lower Jaw Action during Prey Capture by Pelicans

The Auk ◽  
1977 ◽  
Vol 94 (4) ◽  
pp. 785-786 ◽  
Author(s):  
P. J. K. Burton
Keyword(s):  
Prey Capture ◽  
Lower Jaw

Determination of prey capture rates in the stony coral Galaxea fascicularis: a critical reconsideration of the clearance rate concept

2011 ◽  
Vol 92 (4) ◽  
pp. 713-719 ◽  
Author(s):  
Ronald Osinga ◽  
Sanne Van Delft ◽  
Muhammad Wahyudin Lewaru ◽  
Max Janse ◽  
Johan A.J. Verreth
Keyword(s):  
Clearance Rate ◽  
Prey Item ◽  
Prey Capture ◽  
Capture Efficiency ◽  
Accurate Estimation ◽  
Surrounding Water ◽  
Galaxea Fascicularis ◽  
Feeding Experiments ◽  
Total Capture ◽  
Capture Rates

In order to determine optimal feeding regimes for captive corals, prey capture by the scleractinian coral Galaxea fascicularis was determined by measuring clearance of prey items from the surrounding water. Colonies of G. fascicularis (sized between 200 and 400 polyps) were incubated in 1300 ml incubation chambers. Nauplii of the brine shrimp Artemia sp. were used as the prey item. A series of incubation experiments was conducted to determine the maximal capture per feeding event and per day. To determine maximal capture per feeding event, total uptake of nauplii after one hour was determined for different prey item availabilities ranging from 50 to 4000 nauplii per polyp. To determine maximal capture per day, the corals were subjected to four repetitive feeding events at three different prey item densities (50, 100 and 150 nauplii per polyp). Alongside these quantitative experiments, it was tested to what extent the feeding response of corals is triggered by chemical cues. One hour after food addition, extract of Artemia nauplii was added to the incubation chambers to test its effect on subsequent prey capture rates. In all experiments, prey capture was expressed as the number of nauplii consumed per coral polyp. Total capture of Artemia nauplii by G. fascicularis after a single feeding event increased linearly up till a prey item availability of 2000 nauplii per polyp. Maximal capture per feeding event was estimated at 1200 nauplii per polyp, which is higher than rates reported in previous studies. It became apparent that at high densities of Artemia nauplii, the clearance rate method does not discriminate between active capture and passive sedimentation. Repetitive feeding with 50 nauplii per polyp resulted in a constant total prey capture per feeding event. At a supply of 100 nauplii per polyp, total capture decreased after the first feeding event, and remained constant during the subsequent feeding events at a level comparable to the lower food availability. However, at a supply of 150 nauplii per polyp, total capture per event was higher throughout the entire four-hour incubation period, which obfuscates an accurate estimation of the maximal daily food uptake. In all incubations, a decrease in capture efficiency was observed within the course of the feeding event. In all repetitive feeding experiments, capture efficiency increased immediately upon addition of a new batch of food. This increase in efficiency was not caused by a priming effect of extract of Artemia. The inconsistencies in the data show that estimates of prey capture based on clearance rates should be interpreted with caution, because this method does not take into account potential dynamics of prey capture and release.

scholarly journals Resting networks and personality predict attack speed in social spiders

2019 ◽  
Author(s):  
Edmund R. Hunt ◽  
Brian Mi ◽  
Rediet Geremew ◽  
Camila Fernandez ◽  
Brandyn M. Wong ◽  
...  
Keyword(s):  
Social Network ◽  
Developmental Stages ◽  
Prey Capture ◽  
Large Prey ◽  
Interaction Patterns ◽  
Social Spiders ◽  
Behavioral Traits ◽  
The Social ◽  
Group Members ◽  
Behavioral Attributes

AbstractGroups of social predators capture large prey items collectively, and their social interaction patterns may impact how quickly they can respond to time-sensitive predation opportunities. We investigated whether various organizational levels of resting interactions (individual, sub-group, group), observed at different intervals leading up to a collective prey attack, impacted the predation speed of colonies of the social spider Stegodyphus dumicola. We found that in adult spiders overall group connectivity (average degree) increased group attack speed. However, this effect was detected only immediately before the predation event; connectivity two and four days before prey capture had little impact on the collective dynamics. Significantly, lower social proximity of the group’s boldest individual to other group members (closeness centrality) immediately prior and two days before prey capture was associated with faster attack speeds. These results suggest that for adult spiders, the long-lasting effects of the boldest individual on the group’s attack dynamics are mediated by its role in the social network, and not only by its boldness. This suggests that behavioural traits and social network relationships should be considered together when defining keystone individuals in some contexts. By contrast, for subadult spiders, while the group maximum boldness was negatively correlated with latency to attack, no significant resting network predictors of latency to attack were found. Thus, separate behavioural mechanisms might play distinctive roles in determining collective outcomes at different developmental stages, timescales, and levels of social organization.Significance statementCertain animals in a group, such as leaders, may have a more important role than other group members in determining their collective behavior. Often these individuals are defined by their behavioral attributes, for example, being bolder than others. We show that in social spiders both the behavioral traits of the influential individual, and its interactions with other group members, shape its role in affecting how quickly the group collectively attacks prey.

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