Effect of various warm-up devices on bat velocity of intercollegiate baseball players

A variety of warm-up devices are available to baseball players to use before their game at-bat. Past baseball research evaluating warm-up devices indicates that implements that are ±12% of standard game bat weight produce the greatest bat velocities for high school and intercollegiate players. The purpose of this study was to examine the effect of various warm-up devices on bat velocity (BV) of intercollegiate baseball players. Twenty-two Division I intercollegiate baseball players (age = 20.0 ± 1.5 years, height = 182.6 ± 8.3 cm, body mass = 91.4 ± 11.4 kg, lean body mass = 78.8 ± 8.9 kg, % body fat = 13.6 ± 3.8) participated in a warm-up with 1 of 10 weighted devices on separate days. Each of the 10 testing sessions consisted of a standardized warm-up, 3 dry swings as hard as possible with the assigned warm-up device, 2 comfortable dry swings with a standard game baseball bat followed by 3 game swings (20-second rest between swings) while hitting a baseball off of a batting tee with the same standard game baseball bat. Results indicated that there were no statistically significant differences in BV after using any of the 10 warm-up devices. For male intercollegiate baseball players, results indicate that warm-up devices varying from 623.7 to 2,721.5 g (22-96 oz.) did not change mean BV of a standard game baseball bat, suggesting that intercollegiate players can use any of the 10 warm-up devices in the on-deck circle and maintain their BV. Therefore, personal preference as to which warm-up implement to use in the on-deck circle is advised.     

Effect of various warm-up devices on bat velocity of intercollegiate softball players

Numerous warm-up devices are available for use by softball players while they are in the on-deck circle. It is difficult to know which warm-up device produces the greatest bat velocity (BV) in the batter's box for softball players because on-deck studies with these individuals are sparse. Because the majority of warm-up device research has been conducted with baseball players, the primary purpose of this study was to examine the effect of various warm-up devices on the BV of female intercollegiate softball players and compare the results with those of male baseball players. A secondary purpose was to evaluate 2 new commercially available resistance devices as warm-up aids. Nineteen Division I intercollegiate softball players (age = 19.8 ± 1.2 years, height = 167.0 ± 4.7 cm, body mass = 69.2 ± 8.6 kg, lean body mass = 49.6 ± 3.6 kg, % body fat = 27.9 ± 5.9) participated in a warm-up with 1 of 8 resistance devices on separate days. Each of the 8 testing sessions had players perform a standardized dynamic warm-up, 3 maximal dry swings mimicking their normal game swing with the assigned warm-up device, 2 comfortable dry swings with a standard 83.8-cm, 652-g (33-in., 23-oz) softball bat followed by 3 maximal game swings (20-second rest between swings) while hitting a softball off a batting tee with the same standard softball bat. Results indicated that there were no statistically significant differences in BV after using any of the 8 warm-up devices (510.3-2,721.5 g or 18-96 oz) similar to in previous baseball research. This indicates that the results for both male and female intercollegiate players are similar and that intercollegiate softball players can use any of the 8 warm-up devices in the on-deck circle and have similar BVs. However, similar to in other previous baseball research, it is not recommended that female intercollegiate softball players warm up with the popular commercial donut ring in the on-deck circle because it produced the slowest BV.     

Numerical analysis of maximal bat performance in baseball

Metal baseball bats have been experimentally demonstrated to produce higher ball exit velocity (BEV) than wooden bats. In the United States, all bats are subject to BEV tests using hitting machines that rotate the bat in a horizontal plane. In this paper, a model of bat-ball impact was developed based on 3-D translational and rotational kinematics of a swing performed by high-level players. The model was designed to simulate the maximal performance of specific models of a wooden bat and a metal bat when swung by a player, and included material properties and kinematics specific to each bat. Impact dynamics were quantified using the finite element method (ANSYS/LSDYNA, version 6.1). Maximum BEV from both a metal (61.5 m/s) and a wooden (50.9 m/s) bat exceeded the 43.1 m/s threshold by which bats are certified as appropriate for commercial sale. The lower BEV from the wooden bat was attributed to a lower pre-impact bat linear velocity, and a more oblique impact that resulted in a greater proportion of BEV being lost to lateral and vertical motion. The results demonstrate the importance of factoring bat linear velocity and spatial orientation into tests of maximal bat performance, and have implications for the design of metal baseball bats.     

Determining ideal baseball bat weights using muscle force-velocity relationships

The equations of physics for bat-ball collisions were coupled to the physiology of the muscle force-velocity relationship to compute the ideal bat weight for individual baseball players. The results of this coupling suggest that some batters use bats that are too heavy for them, and some batters use bats that are too light, but most experienced batters use bats that are just right. However, ideal bat weight is not correlated with height, weight, or age. Decades of prior physiological research on force-velocity relationships of isolated muscle have shown that hyperbolic curves usually fit the data best. However, for the present data, the hyperbolic curves fit only one class of subjects best: for the others a straight line provides the best fit. We hypothesize that these two classes of players use different control strategies.     

Effects of training with a dynamic moment of inertia bat on swing performance

The purpose of this study was to investigate the effects of the 8-week dynamic moment of inertia (DMOI) bat training on swing velocity, batted-ball speed, hitting distance, muscle power, and grip force. The DMOI bat is characterized in that the bat could be swung more easily by reducing the moment of inertia at the initial stage of swing without decreasing the bat weight and has a faster swing velocity and lower muscle activity. Seventeen varsity baseball players were randomly assigned to the DMOI bat training group (n = 9) and the normal bat training group (n = 8). The training protocol was 7 swings each set, 5-8 sets each time, 3 times each week, and 8 weeks' training period. The results showed that the swing training with the DMOI bat for 8 weeks significantly increased swing velocity by about 6.20% (96.86 ± 8.48 vs. 102.82 ± 9.93 km·h(-1)), hitting distance by about 6.69% (80.06 ± 9.16 vs. 84.99 ± 7.26 m), muscle power of the right arm by about 12.04% (3.34 ± 0.41 vs. 3.74 ± 0.61 m), and muscle power of the left arm by about 8.23% (3.36 ± 0.46 vs. 3.61 ± 0.39 m) (p < 0.05). Furthermore, the DMOI bat training group had a significantly better change percentage in swing velocity, hitting distance, and grip force of the left hand than did the normal bat training group (p < 0.05). The findings suggested that the swing training with the DMOI bat has a positive benefit on swing performance and that the DMOI bat could be used as a new training tool in baseball.     

The Temporal Structure of Vertical Arm Movements

The present study investigates how the CNS deals with the omnipresent force of gravity during arm motor planning. Previous studies have reported direction-dependent kinematic differences in the vertical plane; notably, acceleration duration was greater during a downward than an upward arm movement. Although the analysis of acceleration and deceleration phases has permitted to explore the integration of gravity force, further investigation is necessary to conclude whether feedforward or feedback control processes are at the origin of this incorporation. We considered that a more detailed analysis of the temporal features of vertical arm movements could provide additional information about gravity force integration into the motor planning. Eight subjects performed single joint vertical arm movements (45° rotation around the shoulder joint) in two opposite directions (upwards and downwards) and at three different speeds (slow, natural and fast). We calculated different parameters of hand acceleration profiles: movement duration (MD), duration to peak acceleration (D PA), duration from peak acceleration to peak velocity (D PA-PV), duration from peak velocity to peak deceleration (D PV-PD), duration from peak deceleration to the movement end (D PD-End), acceleration duration (AD), deceleration duration (DD), peak acceleration (PA), peak velocity (PV), and peak deceleration (PD). While movement durations and amplitudes were similar for upward and downward movements, the temporal structure of acceleration profiles differed between the two directions. More specifically, subjects performed upward movements faster than downward movements; these direction-dependent asymmetries appeared early in the movement (i.e., before PA) and lasted until the moment of PD. Additionally, PA and PV were greater for upward than downward movements. Movement speed also changed the temporal structure of acceleration profiles. The effect of speed and direction on the form of acceleration profiles is consistent with the premise that the CNS optimises motor commands with respect to both gravitational and inertial constraints.     

High-performance vision training improves batting statistics for University of Cincinnati baseball players

Purpose

Baseball requires an incredible amount of visual acuity and eye-hand coordination, especially for the batters. The learning objective of this work is to observe that traditional vision training as part of injury prevention or conditioning can be added to a team''s training schedule to improve some performance parameters such as batting and hitting.

Methods

All players for the 2010 to 2011 season underwent normal preseason physicals and baseline testing that is standard for the University of Cincinnati Athletics Department. Standard vision training exercises were implemented 6 weeks before the start of the season. Results are reported as compared to the 2009 to 2010 season. Pre season conditioning was followed by a maintenance program during the season of vision training.

Results

The University of Cincinnati team batting average increased from 0.251 in 2010 to 0.285 in 2011 and the slugging percentage increased by 0.033. The rest of the Big East''s slugging percentage fell over that same time frame 0.082. This produces a difference of 0.115 with 95% confidence interval (0.024, 0.206). As with the batting average, the change for University of Cincinnati is significantly different from the rest of the Big East (p = 0.02). Essentially all batting parameters improved by 10% or more. Similar differences were seen when restricting the analysis to games within the Big East conference.

Conclusion

Vision training can combine traditional and technological methodologies to train the athletes'' eyes and improve batting. Vision training as part of conditioning or injury prevention can be applied and may improve batting performance in college baseball players. High performance vision training can be instituted in the pre-season and maintained throughout the season to improve batting parameters.     

Differences in the Head Movement During Baseball Batting between Skilled Players and Novices

ABSTRACT: Nakata, H, Miura, A, Yoshie, M, and Kudo, K. Differences in the head movement during baseball batting between skilled players and novices. J Strength Cond Res 26(10): 2632-2640, 2012-We investigated the pattern of head movement during baseball batting in 8 skilled players and 9 unskilled novices, using a high-speed video camera. The 2 directions of head movement were analyzed as an X-axis (from the home plate to the pitcher's plate) and Z-axis (vertical downward). On the X-axis, peak latency, peak value, the distance from the peak to the value at bat-ball impact, and data variability were compared between the 2 groups. On the Z-axis, peak latency, downward distance, and data variability were analyzed. Peak latency on the X-axis occurred significantly earlier in baseball players than in novices (p < 0.001), and the difference between the minimum peak and impact was significantly larger in the players (p < 0.05). The variability in peak latency on the X-axis was significantly larger in the novices (p < 0.05). The variability in peak value on the Z-axis was also significantly larger in the novices (p < 0.05). Our findings showed that the significant differences in head movement between the 2 groups should help baseball players, beginners, coaches, and strength and conditioning professionals to improve performance, be effectively applied to actual practice, and enhance coaching for batting.     

Analysis of Biomechanical Characteristics of Football Players at Different Levels Kicking with the Inner Edge of Instep

This study aims to analyze the difference in biomechanical properties of football players at different levels when kicking the football with the inner edge of the instep. Before the experiment, ten football players were selected; five were higher than the national level (group A), and the other five players were lower than the national level II (group B). During the experiment, the motion process was captured by a high-speed camera for biomechanical analysis. It was found that in group A, the thigh and leg swung in less time and larger amplitude, the acceleration of backswing and forward swing of the leg was larger, and the angular velocity of forward swing was also larger. At the moment of touching the ball, in the sagittal plane, the ankle joint angle and angular velocity of group A were larger than those of group B (P < 0.05). In conclusion, the high-level athletes can complete the high-quality kicking through a larger swing amplitude and speed of the kicking leg. In the training process, the athletes should pay attention to the speed and strength of the kicking leg to improve the kicking level.     

Relationship between upper-body strength and bat swing speed in high-school baseball players

This study aimed to clarify the relationship between upper-body strength and bat swing speed in high-school baseball players and to examine the physical characteristics of home run hitters (sluggers). The subjects were 30 male high-school baseball players with national tournament experience at the Koshien Stadium. Bat swing speed exerted by full effort was measured with a microwave-type speed-measuring instrument. One-repetition maximum (1RM) of a bench press (BP), BP power (bench power) using a light load (30 kg), and isokinetic chest press (0.4, 0.8, 1.2 m·s(-1)) were measured as upper-body strength. The relationships between bat swing speed and upper-body strength values were examined. Additionally, the t-test was used to reveal the mean differences between 14 home run hitters (group A) and 16 mediocre hitters (group B) for each measurement value. The bat swing speed showed significant and middle correlations with the 1RM BP (r = 0.59), bench power (0.41), and isokinetic chest press (0.48-0.55). Group A had significantly higher values in bench power and isokinetic chest press (high-speed) per kilogram of body weight than did group B. The swing speed showed significant correlations (r = 0.62) with the 1RM BP in group B but not in group A. In conclusion, to improve the hitting power of high-school baseball players, it may also be important to develop bench power with light loads in addition to 1RM BP.     

Electromyographic activity of lower limbs to stop baseball batting

We investigated the muscle activation pattern of the lower limbs for the stopping motion of baseball batting by recording surface electromyography (EMG) from 8 muscles, the left and right rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG) muscles. First, muscle activities for 'Swing' and 'Stopping' trials were examined in 10 skilled baseball players and 10 unskilled novices. Second, the characteristics of EMG activities for 'Stopping' were compared between the 2 groups. The peak latencies of EMG were significantly shorter in 'Stopping' than in 'Swing' at the right-TA, left-BF, and left-MG between both groups. The peak amplitudes of EMG activity were significantly larger in 'Swing' than in 'Stopping' at the right-TA, left-BF, and left-MG in both groups. In addition, the peak amplitudes of EMG activity for 'Stopping' were significantly larger in the players than in novices at the right-RF and right-TA. The characteristics of EMG activity clearly differed between 'Swing' and 'Stopping,' and between baseball players and nonplayers, indicating that evaluating the EMG activity in batting enables the understanding of proficiency. Our findings should help players, novices, and coaches to optimize batting performance.     

Pure acceleration is the primary determinant of speed to first-base in major-league baseball game situations

The purposes of this research were to (a) quantify interval sprint times between Home-Plate and the Foul-Line and the Foul-Line and First-Base, (b) determine if differences exist in interval velocities and acceleration between left- and right-handed batters or between-position groupings, and (c) to quantify determinants of time to First-Base in Major-League Baseball players during actual games. A total of 1,896 sprint times to the Foul-Line (13.7 m) and First-Base (27.4 m) were recorded in 302 baseball players by a single coach, positioned in the dugout with a hand-held stopwatch. Interval velocities and accelerations were computed between Home-Plate and the Foul-Line and the Foul-Line and First-Base; average velocity and acceleration were also determined over the entire 27.4 m. Velocity and acceleration for left-handed batters were greater than for right-handed batters from Home-Plate to the Foul-Line and from Home-Plate to First-Base; however, there were no differences in velocity or acceleration from the Foul-Line to First-Base. Interval velocity was significantly greater for outfielders and infielders compared with that for catchers from Home-Plate to the Foul-Line and from the Home-Plate to First-Base. Outfielders were faster than catchers from the Foul-Line to First-Base; no other between-group differences were evident. Accelerations from Home-Plate to the Foul-Line and from Home-Plate to First-Base were greater for outfielders compared with infielders and catchers. Infielders accelerated at greater rates than did catchers between these intervals. There were no between-position differences in acceleration from the Foul-Line to First-Base. These data indicate that time to First-Base is most affected by acceleration from Home-Plate to the Foul-Line. Coaches should implement strategies that encourage players to sprint maximally over the first 13.7 m to maximize chances of successfully reaching First-Base.     

The Aversive Effect of Electromagnetic Radiation on Foraging Bats—A Possible Means of Discouraging Bats from Approaching Wind Turbines

Large numbers of bats are killed by collisions with wind turbines and there is at present no accepted method of reducing or preventing this mortality. Following our demonstration that bat activity is reduced in the vicinity of large air traffic control and weather radars, we tested the hypothesis that an electromagnetic signal from a small portable radar can act as a deterrent to foraging bats. From June to September 2007 bat activity was compared at 20 foraging sites in northeast Scotland during experimental trials (radar switched on) and control trials (no radar signal). Starting 45 minutes after sunset, bat activity was recorded for a period of 30 minutes during each trial and the order of trials were alternated between nights. From July to September 2008 aerial insects at 16 of these sites were sampled using two miniature light-suction traps. At each site one of the traps was exposed to a radar signal and the other functioned as a control. Bat activity and foraging effort per unit time were significantly reduced during experimental trials when the radar antenna was fixed to produce a unidirectional signal therefore maximising exposure of foraging bats to the radar beam. However, although bat activity was significantly reduced during such trials, the radar had no significant effect on the abundance of insects captured by the traps.     

The relation between anthropometric and physiological variables and bat velocity of high-school baseball players before and after 12 weeks of training

The purpose of this article was to investigate the relation between anthropometric and physiological variables to linear bat swing velocity (BV) of 2 groups of high-school baseball players before and after completing a 12-week periodized resistance exercise program. Participants were randomly assigned to 1 of 2 training groups using a stratified sampling technique. Group 1 (n = 24) and group 2 (n = 25) both performed a stepwise periodized resistance exercise program and took 100 swings a day, 3 d·wk-1, for 12 weeks with their normal game bat. Group 2 performed additional rotational and full-body medicine ball exercises 3 d·wk-1 for 12 weeks. Fourteen variables were measured or calculated before and after 12 weeks of training. Anthropometric and physiological variables tested were height, body mass, percent body fat, lean body mass (LBM), dominant torso rotational strength (DTRS) and nondominant torso rotational strength (NDTRS), sequential hip-torso-arm rotational strength measured by a medicine ball hitter's throw (MBHT), estimated 1 repetition maximum parallel squat (PS) and bench press (BP), vertical jump (VJ), estimated peak power, angular hip velocity (AHV), and angular shoulder velocity (ASV). The baseball-specific skill of linear BV was also measured. Statistical analysis indicated a significant moderately high positive relationship (p ≤ 0.05) between prelinear BV and pre-NDTRS for group 1, pre-LBM, DTRS, NDTRS, peak power, and ASV for group 2; moderate positive relationship between prelinear BV and preheight, LBM, DTRS, peak power, BP, PS, and ASV for group 1, preheight, body mass, MBHT, BP, and PS for group 2. Significantly high positive relationships were indicated between postlinear BV and post-NDTRS for group 1, post-DTRS and NDTRS for group 2; moderately high positive relationships between postlinear BV and post-LBM, DTRS, peak power, BP, and PS for group 1, postheight, LBM, VJ, peak power for group 2; moderate positive relationships between postlinear BV and postheight, body mass, MBHT, and VJ for group 1, postbody mass, MBHT, BP, PS, and ASV for group 2. Significantly low positive relationships were indicated between prelinear BV and prebody mass, MBHT, and VJ for group 1, pre-VJ and AHV for group 2; postlinear BV and post-AHV for group 2. These data show that significant relationships do exist between height, body mass, LBM, rotational power, rotational strength, lower body power, upper and lower body strength, AHV, and ASV to linear BV of high-school baseball players. Strength coaches may want to consider using this information when designing a resistance training program for high-school baseball players. Those recruiting or scouting baseball players may want to use this information to further develop ways of identifying talented players. However, one should be cautious when interpreting this information when designing strength training programs for high-school baseball players to increase linear BV.     

The effects of two stretching protocols on the reactive strength index in female soccer and rugby players

The purpose of this study was to investigate the effects of 2 stretching protocols on stretch-shortening cycle performance in female Division I soccer players and female club rugby players. Fifteen soccer and rugby players (20.1 ± 5.9 years, 170.5 ± 14.2 cm, 70.4 ± 22.3 kg) participated in 3 test sessions with different treatments. The first treatment involved a warm-up of 10 minutes of exercise on a cycle ergometer (warm-up only [WO]), the second was this warm-up followed by static stretching (SS), and the third was this warm-up followed by dynamic stretching (DS). The treatments were administered randomly to negate an order effect. Each treatment was immediately followed by a reactive strength index (RSI) test requiring the athletes to drop off a box (45 cm in height) on to a force plate and upon landing immediately jump into the air while minimizing contact time (CT, milliseconds) and maximizing flight time (FT, milliseconds). The RSI was FT: CT. Repeated measures analysis of variance indicated that a significant treatment effect existed for RSI (F = 7.95, 2; p = 0.002) and FT (F = 7.43, 2; p = 0.003) but no significant effect for CT (F = 1.53, 2; p = 0.235). The RSI and FT were significantly greater in DS compared with that in SS and WO. Dynamic stretching is the preferred warm-up before an athletic event involving considerable jumping.     

The effect of static stretching on phases of sprint performance in elite soccer players

The purpose of this study was to determine which phase of a 30-m sprint (acceleration and/or maximal velocity) was affected by preperformance static stretching. Data were collected from 20 elite female soccer players. On two nonconsecutive days, participants were randomly assigned to either the stretch or no-stretch condition. On the first day, the athletes in the no-stretch condition completed a standard warm-up protocol and then performed three 30-m sprints, with a 2-minute rest between each sprint. The athletes in the stretch condition performed the standard warm-up protocol, completed a stretching routine of the hamstrings, quadriceps, and calf muscles, and then immediately performed three 30-m sprints, also with a 2-minute rest between each sprint. On the second day, the groups were reversed, and identical procedures were followed. One-way repeated-measures analyses of variance revealed a statistically significant difference in acceleration (p < 0.0167), maximal-velocity sprint time (p < 0.0167), and overall sprint time (p < 0.0167) between the stretch and no-stretch conditions. Static stretching before sprinting resulted in slower times in all three performance variables. These findings provide evidence that static stretching exerts a negative effect on sprint performance and should not be included as part of the preparation routine for physical activity that requires sprinting.     

Selective ion binding and membrane activity of synthetic cyclopeptides

Four cyclic peptides related to the membrane-active complexones PV, cyclo-(L-Pro-Lval-D-Pro-D-Val)3, and valinomycin were synthesized: (1) cyclo-(L-Pro-L-Ala-D-Val)3 or PVPA, (2) cyclo-(L-Ala-L-Val-D-Pro-D-Val)3 or PVAV, (3) cyclo-(L-Pro-L-Val-D-Pro-D-Val)2-L-Pro-D-Val or PV-10, (4) cyclo-(L-Pro-L-Val-D-Pro-D-Val)2 or PV-8. In a two-phase extraction assay the affinity of PV and PVPA for alkali picrates was about three orders or magnitude greater than that of valinomycin. It was about equal to valinomycin for PVAV and much lower for PV-10 and PV-8. PV, PVPA and PVAV showed a selectivity sequence similar to that of valinomycin, namely K+ approximately Rb+ greater than Cs+ greater than Na+ greater than Li+. In the series PV, PV-10, PV-, the preference for K+ over Na+ was 700, 5 and less than 1, respectively. Thus, it was possible to reverse the selectivity of PV for K+ over Na+ by reducing the ring size from 12 to 8 amino acid residues. In sheep red cell lipid bilayer membranes PVPA increased the membrane conductance significantly in the presence of either KCl or NaCl but it was less potent than PV. PV-10, PV-8 and PVAV on the other hand were ineffective in this assay. The inactivity of PVAV as a potassium carrier in membrane was in contrast to its high affinity for potassium picrate in two-phase assays. Such a behaviour may be observed of a compound that has too low an aqueous cation binding constant to use the solution-complexation mechanism of PV (Davis et al. (1976) Biochemistry 15, 768--774 and Pinkerton et al. (1969) Biochem. Biophys. Res. Commun. 35, 512--518) and too slow binding and release kinetics to use the interfacial-complexation mechanism of valinomycin.     

Does interspecific competition drive patterns of habitat use in desert bat communities?

Bodies of water are a key foraging habitat for insectivorous bats. Since water is a scarce and limiting resource in arid environments, bodies of open water may have a structuring effect on desert bat communities, resulting in temporal or spatial partitioning of bat activity. Using acoustic monitoring, we studied the spatial and temporal activity patterns of insectivorous bats over desert ponds, and hypothesised that sympatric bat species partition the foraging space above ponds based on interspecific competitive interactions. We used indirect measures of competition (niche overlap and competition coefficients from the regression method) and tested for differences in pond habitat selection and peak activity time over ponds. We examined the effect of changes in the activity of bat species on their potential competitors. We found that interspecific competition affects bat community structure and activity patterns. Competing species partitioned their use of ponds spatially, whereby each species was associated with different pond size and hydroperiod (the number of months a pond holds water) categories, as well as temporally, whereby their activity peaked at different hours of the night. The drying out of temporary ponds increased temporal partitioning over permanent ponds. Differences in the activity of species over ponds in response to the presence or absence of their competitors lend further support to the role of interspecific competition in structuring desert bat communities. We suggest that habitat use and night activity pattern of insectivorous bats in arid environments reflect the trade-offs between selection of preferred pond type or activity time and constraints posed by competitive interactions.     

Noctuid moths show neural and behavioural responses to sounds made by some bat-marking rings

Coloured rings are often used for marking bats so that specific individuals can be recognized. We noticed that the rings of mouse-eared bats, Myotis myotis and Myotis blythii, in a combination of one plastic-split and one metallic ring on the same forearm, emitted sounds that were largely ultrasonic each time the rings met in flight. We recorded the ring sounds and the echolocation calls produced by the bats, and played them back to neural preparations of lesser yellow underwing moths, Noctua comes, while making extracellular recordings from the moths' A1 auditory receptors. The peak energy of the ring sounds occurred much closer in frequency to the moth's best auditory frequency (the frequency at which the moth has the lowest auditory threshold) than the peak energy of the calls, for both bat species, and the ring sounds were detected at a threshold 5-6 dB peSPL lower than the calls. Moths performed evasive manoeuvres to playbacks of ring sounds more frequently than they did to control (tape noise) sequences. These neural and behavioural responses imply that certain bats should not be marked with two rings on one wing, as this may make the bat more apparent to tympanate insects, and may therefore reduce its foraging success. Copyright 1999 The Association for the Study of Animal Behaviour.     

同一山洞中五种蝙蝠的回声定位比较及生态位的分化

对同一山洞中5种蝙蝠的回声定位叫声和外部形态作了比较分析,根据蝙蝠回声定位叫声,形态特征与捕食策略之间的联系,并结合部分的野外观察研究,推断其捕食生境及捕食策略,并对洞中5种共栖蝙蝠的生态位分化进行了分析;研究结果如下：（1）南蝠（Ia io)在地面或树冠中间的开阔空间捕食个体较大的昆虫;（2）大鼠耳蝠（Myotis myotis)主要以掠食性方式（gleaning) 捕食森林或草地地表面的昆虫;（3）黄大蹄幅（Hipposideros pratti)主要在树冠周围或树冠上方进行捕蝇器式（Fly-catching)（即倒挂于一固定枝条或地点,探索周围飞行或接近的昆虫,探索到后捕捉回原倒挂地点再进食）或飞行捕食,它主要捕食个体较大的甲虫;（4）角菊头蝠（Rhinolophus cornutus)主要在较密集树木中（枝叶间）,农田及树木周围捕食型较小的翼拍动昆虫;（5）三叶蹄幅（Aselliscus wheeleri)是在树木,灌丛或在其周围空间内捕食较小的翼拍动昆虫,但其食性可能菊头蝠不同,根据以上研究结果,认为这5种蝙蝠的取食生态位存在着明显的分化。