Muscle power production during intermittent swimming in bluegill sunfish.

Locomotion is essential for the survival and fitness of animals. Fishes have evolved a variety of mechanisms to minimize the cost of transport. For instance, bluegill sunfish have recently been shown to employ intermittent swimming in nature and in laboratory conditions.

Drag coefficient estimates from coasting bluegill sunfish Lepomis macrochirus.

The drag coefficient bluegill sunfish Lepomis macrochirus was estimated from coasting deceleration as (mean ± SD) 0.0154 ± 0.0070 at a Reynolds number of 41,000 ± 14,000.

Linking muscle metabolism and functional variation to field swimming performance in bluegill sunfish (Lepomis macrochirus).

Skeletal muscle has diverse mechanical roles during locomotion. In swimming fish, power-producing muscles work in concert with the accessory muscles of the fins which augment and control power transfer to the water. Although fin muscles represent a significant proportion of the locomotor muscle mass, their physiological properties are poorly characterized.

Field swimming performance of bluegill sunfish, : implications for field activity cost estimates and laboratory measures of swimming performance.

Mobility is essential to the fitness of many animals, and the costs of locomotion can dominate daily energy budgets. Locomotor costs are determined by the physiological demands of sustaining mechanical performance, yet performance is poorly understood for most animals in the field, particularly aquatic organisms. We have used 3-D underwater videography to quantify the swimming trajectories and propulsive modes of bluegills sunfish (, Rafinesque) in the field with high spatial (1-3 mm per pixel) and temporal (60 Hz frame rate) resolution.

Field swimming behavior in largemouth bass deviates from predictions based on economy and propulsive efficiency.

Locomotion is energetically expensive. This may create selection pressures that favor economical locomotor strategies, such as the adoption of low-cost speeds and efficient propulsive movements. For swimming fish, the energy expended to travel a unit distance, or cost of transport (COT), has a U-shaped relationship to speed.

Locomotor and energetic consequences of behavioral thermoregulation in the sanguivorous leech Hirudo verbana.

Medicinal leeches (Hirudo verbana) thermoregulate with respect to their sanguivorous feeding behavior. Immediate postprandial preferences are for warmer than their initial acclimation temperature (T, 21°C, Petersen et al. 2011), while unfed leeches have a lower preferred temperature (T, 12.

Scaling of the fast-start escape response of juvenile bluegills.

Morphology, size and physiological properties change markedly across fish ontogeny. This impacts locomotor performance and organismal fitness, although the effects are unpredictable due to the complexity of phenotype-function relationships. Morphological and behavioral changes with growth are often paralleled by changes in habitat use, diet and vulnerability to predators.

The effects of steady swimming on fish escape performance.

Escape maneuvers are essential to the survival and fitness of many animals. Escapes are frequently initiated when an animal is already in motion. This may introduce constraints that alter the escape performance.

Trade-offs between performance and variability in the escape responses of bluegill sunfish (Lepomis macrochirus).

Successful predator evasion is essential to the fitness of many animals. Variation in escape behaviour may be adaptive as it reduces predictability, enhancing escape success. High escape velocities and accelerations also increase escape success, but biomechanical factors likely constrain the behavioural range over which performance can be maximized.

Resolving shifting patterns of muscle energy use in swimming fish.

Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy.

Variation in fast-start performance within a population of polyphenic bluegill (Lepomis macrochirus).

Bluegill sunfish Lepomis macrochirus exhibit intraspecific variation in their morphology and swimming performance based on habitat. The pelagic form has a relatively streamlined, fusiform body shape associated with greater steady-state swimming speed and energy economy. In contrast, littoral bluegill have deeper bodies with fins located farther from their center of mass to enhance maneuverability among littoral vegetation.

Serotonin as an integrator of leech behavior and muscle mechanical performance.

The obliquely striated muscle in the leech body wall has a broad functional repertoire; it provides power for both locomotion and suction feeding. It also operates over an unusually high strain range, undergoing up to threefold changes in length. Serotonin (5-HT) may support this functional flexibility, integrating behavior and biomechanics.

Function of a large biarticular hip and knee extensor during walking and running in guinea fowl (Numida meleagris).

Physiological and anatomical evidence suggests that in birds the iliotibialis lateralis pars postacetabularis (ILPO) is functionally important for running. Incorporating regional information, we estimated the mean sarcomere strain trajectory and electromyographic (EMG) amplitude of the ILPO during level and incline walking and running. Using these data and data in the literature of muscle energy use, we examined three hypotheses: (1) active lengthening will occur on the ascending limb of the length-tension curve to avoid potential damage caused by stretch on the descending limb; (2) the active strain cycle will shift to favor active shortening when the birds run uphill and shortening will occur on the plateau and shallow ascending limb of the length-tension curve; and (3) measures of EMG intensity will correlate with energy use when the mechanical function of the muscle is similar.

Mechanisms producing coordinated function across the breadth of a large biarticular thigh muscle.

We examined the hypothesis that structural features of the iliotibialis lateralis pars postacetabularis (ILPO) in guinea fowl allow this large muscle to maintain equivalent function along its anterior-posterior axis. The ILPO, the largest muscle in the hindlimb of the guinea fowl, is a hip and knee extensor. The fascicles of the ILPO originate across a broad region of the ilium and ischium posterior to the hip.

Differential segmental strain during active lengthening in a large biarticular thigh muscle during running.

The iliotibialis lateralis pars postacetabularis (ILPO) is the largest muscle in the hindlimb of the guinea fowl and is thought to play an important role during the stance phase of running, both absorbing and producing work. Using sonomicrometry and electromyography, we examined whether the ILPO experiences differential strain between proximal, central and distal portions of the posterior fascicles. When the ILPO is being lengthened while active, the distal portion was found to lengthen significantly more than either the proximal or central portions of the muscle.

The seed dispersal catapult of Cardamine parviflora (Brassicaceae) is efficient but unreliable.

Premise Of The Study: Seed dispersal performance is an essential component of plant fitness. Despite their significance in shaping performance, the mechanical processes that drive dispersal are poorly understood. We have quantified seed dispersal mechanics in Cardamine parviflora (Brassicaceae), a ballistic disperser that launches seeds with specialized catapult-like structures.

Serotonin modulates muscle function in the medicinal leech Hirudo verbana.

The body wall muscles of sanguivorous leeches power mechanically diverse behaviours: suction feeding, crawling and swimming. These require longitudinal muscle to exert force over an extremely large length range, from 145 to 46 per cent of the mean segmental swimming length. Previous data, however, suggest that leech body wall muscle has limited capacity for force production when elongated.

Leeches run cold, then hot.

Food processing is costly, potentially limiting the energy and time devoted to other essential functions such as locomotion or reproduction. In ectotherms, post-prandial thermophily, the selection of a warm environmental temperature after feeding, may be advantageous in minimizing the duration of this elevated cost. Although present in many vertebrate taxa, this behaviour had not previously been observed in invertebrates.

The mechanical function of linked muscles in the guinea fowl hind limb.

Although mechanical linkages between the proximal and distal limb are present in a range of species, their functional significance is unknown. We have investigated the mechanical function of the flexor cruris lateralis pars pelvica (FCLP), flexor cruris lateralis pars accessoria (FCLA) and gastrocnemius intermedia (GI), a system of linked muscles spanning proximal and distal limb segments in the guinea fowl (Numida meleagris) hind limb. The FCLP, which is in the anatomical position of a hamstring muscle, is the primary component of the linkage.

The physiology and mechanics of undulatory swimming: a student laboratory exercise using medicinal leeches.

The medicinal leech is a useful animal model for investigating undulatory swimming in the classroom. Unlike many swimming organisms, its swimming performance can be quantified without specialized equipment. A large blood meal alters swimming behavior in a way that can be used to generate a discussion of the hydrodynamics of swimming, muscle mechanics, hydrostatic skeletons, and the physiological features that allow leeches to deal with the volume increase and osmotic load imposed by the meal.

The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis).

Explosive dehiscence ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. The resulting seed dispersal patterns have been investigated in some ballistic dispersers, but the mechanical performance of a launch mechanism of this type has not been measured.

The effects of acute temperature change on swimming performance in bluegill sunfish Lepomis macrochirus.

Many fish change gait within their aerobically supported range of swimming speeds. The effects of acute temperature change on this type of locomotor behavior are poorly understood. Bluegill sunfish swim in the labriform mode at low speeds and switch to undulatory swimming as their swimming speed increases.

Mechanical and energetic factors underlying gait transitions in bluegill sunfish (Lepomis macrochirus).

As their swimming speed increased, bluegill sunfish (Lepomis macrochirus) switched from pectoral-fin-powered labriform swimming to undulations of the body axis. This gait transition occurred at a mean swimming speed of 0.24+/-0.

Modulation of pectoralis muscle function in budgerigars Melopsitaccus undulatus and zebra finches Taeniopygia guttata in response to changing flight speed.

Flight power varies in a U-shaped relationship with flight speed, requiring the modulation of flight muscle power in order to meet these changing power demands. The power output of the pectoralis muscle can potentially be modulated by changing strain trajectory and the relative timing and intensity of muscle activity. Pectoralis muscle length change and activity patterns were recorded in budgerigars Melopsitaccus undulatus and zebra finches Taeniopygia guttata at a range of flight speeds using sonomicrometry and electromyography (EMG).