William N. Tavolga

Ultrasound detection by clupeiform fishes.

It has previously been shown that at least one species of fish (the American shad) in the order clupeiforms (herrings, shads, and relatives) is able to detect sounds up to 180 kHz. However, it has not been clear whether other members of this order are also able to detect ultrasound. It is now demonstrated, using auditory brainstem response (ABR), that at least one additional species, the gulf menhaden (Brevoortia patronus), is able to detect ultrasound, while several other species including the bay anchovy (Anchoa mitchilli), scaled sardine (Harengula jaguana), and Spanish sardine (Sardinella aurita) only detect sounds to about 4 kHz. ABR is used to confirm ultrasonic hearing in the American shad. The results suggest that ultrasound detection may be limited to one subfamily of clupeiforms, the Alosinae. It is suggested that ultrasound detection involves the utricle of the inner ear and speculate as to why, despite having similar ear structures, only one group may detect ultrasound.

Acoustic intensity limens in the goldfish

Abstract Thresholds for acoustic stimuli and discrimination limens for different acoustic intensities were obtained in the goldfish, Carassius auratus, by means of avoidance conditioning techniques. The audiogram for this species, based on mean thresholds determined by the staircase audiometric method, ranged from about −25 dB (re 1 μb) at 50 Hz to a low point of almost −46 dB at 500 Hz and rose to −2 dB at 2000 Hz. Above this point the audiogram rose sharply and the practical limit of hearing was at 3000 Hz with a threshold value of about +22 dB. Comparison with other species showed that the sensitivity and frequency range of the goldfish, as well as of other ostariophysine species (possessing a Weberian apparatus), were significantly greater than in other teleosts. Based upon measurements of ambient noise, it was assumed that these threshold values were not masked by external noise. Goldfish were found to be capable of discriminating the intensity of two pure tones when the difference between the two was from 3 to 6 dB of acoustic pressure. Over a range of 30 dB there was no significant difference in the discrimination limen. This limen is smallest in the 300 to 400 Hz range and increases sharply above 1000 Hz. The upper limit of any frequency discrimination is about 1500 Hz. Comparisons of these data with mammalian auditory capacities show both quantitative and qualitative differences, and the problem of distinguishing between the pressure (far-field) and displacement (near-field) reception is discussed.

Signal/noise ratio and the critical band in fishes

Auditory thresholds in the presence of masking noise and masking tones were measured in three species of teleost fishes: goldfish (Carassius auratus, family Cyprinidae); pin fish (Lagodon rhomboides, family Sparidae); African mouth‐Breeder (Tilapia macrocephala, family Cichlidae). In the goldfish, the signal‐to‐noise ratio to broad‐band noise was about 22 dB, and direct measurement of the critical band yielded a value between 100 and 200 Hz. Single‐tone masking effects in the goldfish showed partial remote masking, and strong masking at frequencies within 5 to 20 Hz of the signal. The audiograms for pinfish and Tilapia were significantly higher than in the goldfish, but the signal‐to‐noise ratio values were in the same range. Provisionally, the evidence supports the existence of a critical band in the goldfish, but not in the other species tested. The question of the relationship of signal‐to‐noise ratio to the critical band was discussed in reference to the frequency‐discrimination capacities and hearing...

Acoustic frequency discrimination in the goldfish

The capacity of the goldfish (Carassius auratus) to discriminate between two acoustic frequencies was tested by means of avoidance conditioning techniques. The pulsed-tone method was used in which the subject had to discriminate between a pulsed single frequency and pulses of two frequencies in alternation. Sound pressure levels were kept at 0 dB re 1 μb. This is equivalent to a sensation level of 40 to 45 dB at the frequencies used. Discrimination limens (JND) were determined by the staircase audiometric method. At 200 Hz, the mean JND was 9-4 Hz (4·7 per cent difference); at 500 Hz, the mean JND was 17·4 Hz (3·5 per cent difference); and at 1000 Hz, the mean JND was 50·1 Hz (5·0 per cent difference). The JND at 500 Hz was significantly lower than at the other two frequencies tested. The standard frequencies covered the most sensitive hearing range of this species. Comparison with human frequency discrimination showed that the goldfish JND was an order of magnitude greater. The problem of the mechanism of frequency analysis in fish was discussed.

Effects of Gonadectomy and Hypophysectomy on Prespawning Behavior in Males of the Gobiid Fish, Bathygobius soporator

WRIGHT, P. A. 1946. Response of the melanophores of frog skin to pituitary extracts in vitro. Anat. Rec., 96:540-41. -. 1947. Antagonism of adrenalin and intermedin on the melanophores of frog skin in vitro. Ibid., 99:595. -. 1948. Photoelectric measurement of melanophoral activity of frog skin induced in vitro. Jour. Cell. and Comp. Physiol., 31:111-23. . 1951. Effect of boiling on intermedin activity of frog pituitary. Anat. Rec., 111:501-2. -. 1952a. The effect of colchicine on intermedin-induced melanophoral activity in excised frog skin (Rana pipiens). Ibid., 113:565. --. 1952b. Effect of respiratory inhibitors on melanophoral activity of frog skin in vitro. Biol. Bull., 103:311-12. --. 1953. Iodoacetate poisoning of melanophoral activity in isolated frog skin (Rana pipiens). Anat. Rec., 117:538. --. 1954. A convenient and rapid technique for assay of intermedin. Papers Michigan Acad. Sci., Arts, and Letters, 39:271-79. WRIGHT, P. A., and SABAL, J. 1952. Effect of colchicine on melanophoral activity in excised frog skin (Rana pipiens). Biol. Bull., 103:312-13.

Auditory capacities in fishes: Threshold variability in the blue-striped grunt,Haemulon sciurus

Abstract Auditory thresholds in the blue-striped grunt, Haemulon sciurus (Pisces, Family Pomadasyidae) were determined by the use of avoidance conditioning. A total of 421 threshold determinations on 23 subjects showed both intra-and inter-individual variability. The thresholds from 50 c.p.s. to 200 c.p.s. averaged about 20 db below one microbar, and from 300 c.p.s. the threshold curve rose along an exponential curve to a maximum of 39 db above one microbar at 1,000 c.p.s. The accuracy of the obtained thresholds was about ±2·5 db taking both equipment and testing errors into account. Repeated tests of the same animals at the same frequencies resulted in progressively lower thresholds, and three successive tests were generally required to determine the lowest threshold. This variation was greatest at frequencies below 300 c.p.s. Individual differences in auditory sensitivity among the several animals were distinct, with variations over 10 db at some frequencies. These individual differences were most apparent at frequencies below 300 c.p.s. The latency of response to the signal rose as the threshold was approached, but the frequency of intertrial crossings decreased significantly. The testing method was based on the “staircase” technique, and both 2 db and 5 db steps were used. No significant difference in threshold was observed for the two step sizes.

Pre-Spawning Behavior in the Gobiid Fish, Bathygobius Soporator

The gobiid fish, Bathygobius soporator (Cuvier and Valenciennes), is a shallow water, tidal zone species with shelter-seeking, territorial habits. Males are particularly pugnacious toward each other, and exhibit a combat behavior which comprises a darkening of the coloration, fin erection, gaping, quivering, butting and biting. Prespawning behavior consists of (1) nest preparation, in which the male cleans out a shelter by fanning and scooping; (2) courtship - a light coloration with a blackened chin is exhibited by the male as he approaches a female and vibrates his body and tail; (3) nest entry - the female, if gravid, responds to the courtship by following the male and entering the nest. In spawning, the female extrudes adherent eggs on the inner surface of the nest, while the male releases sperm. After spawning, the male guards and fans the eggs for the 4 to 5 day incubation period. The establishment of a shelter and a territory by a male are necessary before coordinated pre-spawning behavior can take place. Females appear to exhibit less territoriality than males, and young males possess incompletely differentiated territorial, pre-spawning and spawning behavior patterns. In testing the reactions of resident males toward introduced animals, the tests had to be spaced in time sufficiently to avoid an overlapping of responses, because the reactions of the resident persist for some time after the removal of the intruder. The speed and type of reaction by the resident male could be influenced by rapid repetition of the tests. The first r e a c t i o n - c o m p l e x of the resident male toward an introduced animal comprises an approach to the intruder and, in many cases, is followed by or preceded by a color change. Frequently, especially with large males and gravid females as intruders, this reaction-complex shows a trend toward combat or courtship, respectively, before any activity on the part of the intruder. The responses of the introduced animals are varied but tend mostly toward retreat in small males and non-gravid females, combat in large males, and following in gravid females. The subsequent behavior of the resident shows a differentiation according to the sex, size and gonadal stage of the intruder. Combat is predominant towards large males, whereas courtship occurs toward gravid females. Sex discrimination by the resident male is variable, and the sensory cues involved are primarily behavioral in nature. It is thought that the intruding animal presents several visual cues (and possible non-visual ones), and these cues form a pattern which stimulates, channels and re-enforces, in that order, the behavior of the resident male.

ACOUSTIC ORIENTATION IN THE SEA CATFISH, GALEICHTHYS FELIS*

In an aquatic medium, the acoustic channel of communication appears to be the most effective. Chemical stimuli are transmitted slowly and are essentially nondirectional. Penetration of light is severely limited by turbidity, which is characteristic of most areas. In spite of the high impedance of water to the transmission of sound ( 150,000 acoustic ohms as opposed to about 42 acoustic ohms in air), the density of the medium permits faster transmission (approximately 1,500 m/sec in water and 330 m/sec in air) with consequent lower energy loss with distance. The acoustic sense, therefore, becomes the most impurtant distance receptor system. It is now well known that many species of fish produce sounds.IB The majority of sounds are low frequency pulses of short duration, with major energy below 100 Hz, although a few species produce sounds of a more sustained nature at frequencies of 300 Hz or more. Such low frequency sounds are generally produced by means of the swim bladder and its associated musculature, and some species possess highly specialized sonic mechanisms. In addition, higher frequency stridulatory sounds are sometimes produced, and very low frequency hydrodynamic noises result from locomotor activity. The hearing range for most fishes is also limited to the low frequencies.I8 Few species are able to detect frequencies above approximately 2,000 Hz, and the optimum range is usually from 100 to 500 Hz. Exceptions to this are found among the Ostariophysi, in which the presence of the Weberian ossicles evidently enhances not only overall sensitivity but high frequency response as well. This order of teleosts also possesses better pitch discrimination, and within the optimum range of frequencies some ostariophysines can discriminate differences of the order of 3 % (about a quarter-tone) . Most teleost fishes have two acoustic receptor systems. The inner ear and swim bladder form one of these systems, and this complex is primarily sensitive to the pressure oscillations (far-field) in the medium, since the swim bladder acts as an acoustic discontinuity in an otherwise acoustically transparent organism. The lateral line system, on the other hand, is an array of displacement-sensitive receptors that can detect particle displacements of the medium (near-field) in the order of magnitude of 20 Angstroms. The lateral line, therefore, can detect currents and other movements of the medium, but also low frequency (probably below 200 Hz) vibrations and similar hydrodynamic phenomena.3 Although many fishes are known to produce sounds, the exact functions of these sounds have been established for only a few species.18 Sounds are associated with alarm and territorial behavior, and in several instances, sounds play a definite role in courtship and spawning behavior. The possibility that sounds may be associated with orientation in fishes has been only sparsely investigated. Griffin5 reported a single case of a marine animal

Scotopic thresholds for monochromatic light in the cichlid fish, Tilapia heudelotii macrocephala

Abstract By means of avoidance conditioning techniques, thresholds for monochromatic light from 400 to 675 nm were obtained in the African mouth-breeding cichlid fish ( Tilapia heudelotn macrocephala ). The light stimulus was presented through overhead illumination, and the thresholds were calculated after dark-adaptation. Light intensity was measured in terms of irradiance (μW/cm 2 ) Peak sensitivity was at 525 nm with a threshold value of −4.63 log μW/cm 2 (= 234 × 10 −5 μW/cm 2 )

Application of the Concept of Levels of Organization to the Study of Animal Communication

The influence of the behavior of one animal on the behavior of another of the same or a different species is a well-known, extensively studied phenomenon. Whether this phenomenon is called “communication,” “interaction,” “signaling,” “language,” or some other name is often a matter of definition. It is sometimes reminiscent of Alice’s conversation with Humpty Dumpty: “When I use a word,” Humpty Dumpty said... “it means just what I choose to mean—neither more or less.” “The question is,” said Humpty Dumpty, “which is to be the master—that’s all.”... “Impenetrability! That’s what I say!” “Would you tell me please,” said Alice, “what that means?” ... “I meant by ‘impenetrability’ that we’ve had enough of that subject....” (From Through the Looking Glass,by Lewis Carroll.)