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Light responsivity in chick and duck embryos just prior to hatching
Anim. Behav., 1968, 16, 276-280
LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS JUST PRIOR TO HATCHING BY RONALD W . OPPENHEIM*
Washington University, St Louis, Missouri
The visual systems of chick and duck embryos 1 to 2 days before hatching are morphologically (Weysse & Burgess, 1906 ; Coulombre, 1955 ; Shen et al., 1956 ; Schifferli, 1948), biochemically (Lindeman, 1947 ; Rudnick & Waelsch, 1955), and physiologically (Patteta-Queriolo & GarciaAustt, 1956 ; Peters et al., 1958 ; Paulson, 1965) prepared for their role as a receptor of light stimulation . However, whether the embryo is responsive to visual stimulation remains to be determined, since in the final analysis the question of whether an animal is responsive to specific stimulation has to be settled on the basis of behavioural studies . This point is well exemplified in the case of colour vision in the cat . The cat is known to have the neurophysiological and morphological basis for colour vision . Yet the presence of overt spectral vision (Bartley, 1959) has been exceedingly difficult to demonstrate (Sechzer & Brown, 1964) . Both Lindeman (1948) and Kuo (1932) reported that light stimulation becomes effective in producing an overt response in the chick embryo between 18 and 20 days incubation. Lindeman used the pupillary constriction reflex as an indicator of responsivity, while Kuo used opening and closing of the eyelid as the characteristic embryonic response to light. Although the results obtained by these investigators may be correct, their conclusions that the chick embryo is responsive to light are not supported by the brief and incomplete presentation of the data . Neither investigator established a base rate for the occurrence of the response indicator used (both of these responses occur spontaneously in the absence of any specific introduced stimulation) . The possibility that the responses observed were caused by temperature increases from the light source cannot be eliminated, since these investigators did not consider this variable . In addition, both Kuo and Lindeman failed to utilize appropriate controls (the embryos were not examined in the absence of visual stimula-
tion) or to make any statistical analysis in arriving at their conclusions . In the present study, an attempt was made to re-investigate the visual sensitivity of chick and duck embryos under carefully controlled experimental conditions . Methods Subjects Twenty-five chick embryos from a mixed flock of white leghorn chickens and twenty-five Peking duck embryos (Anas platyrhynchos) were used in this investigation . The eggs were incubated in a large forced-draft incubator with a temperature of 100 ° F and a relative humidity of between 65 to 70 per cent . The ages of the chick embryos at the time of testing ranged from 19 days 0 hr of incubation to 20 days 16 hr with an average age of 20 days 4 hr . The ages of the duck embryos ranged from 25 days 6 hr to 27 days 4 hr with an average of 26 days 8 hr. These ages are comparable to chick stages 44 to 45 (Hamburger & Hamilton, 1951) and duck stages 30 to 31 (Koecke, 1958) . Procedure and Apparatus Prior to testing, the eggs were candled to determine the approximate position of the head, and the shell over this region was then removed. The inner shell membrane, chorio-allantoic membrane and the amniotic sac were then carefully cut and deflected over the head region to expose the beak and right eye (Fig . 1, insert) . The behavioural response used in this investigation was beak-clapping, i .e . the rapid opening and closing of the beak which occurs during the latter one-third of incubation in chick and duck embryos . Changes in the rate of beak-clapping previously have been shown to be a sensitive indicator of auditory responsiveness in chick and duck embryos (Gottlieb, 1965) . Beak-clapping was measured by threading a fine (size 4-0) piece of surgical silk through the loose skin on the ventral side of the lower beak and connecting this to a Linearsyn transducer . This served as a strain gauge which detected all vertical displacements of the lower beak . These movements were then recorded automatically on a Sanborn
*Present address : N.C. Dept. of Mental Health, Division of Research, Neuroembryology Lab., Dorothea Dix Hospital, Raleigh, North Carolina. 276
OPPENHEIM : LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS PRIOR TO HATCHING 277
Fig. 1 . Schematic drawing of Plexiglas testing chamber and recording apparatus . A . light source ; B . copper sulphate solution ; C . duck embryo in egg holder with head exposed ; D. thermistor probe ; E. string attached to embryo's bill passing through hole in testing box ; F . heating unit ; G. fan for circulating heat ; H . strain gauge ; distance between strain gauge and embryo is approximately 30 inches .
Fflosee-+4 A
CHICK 14
Fig. 2. A,, movement artifact ; A, beak-clapping. Quality of beak-clapping is different in the two embryos . The ducks tend to have a more rapid rate of beak-clapping with lower amplitude than the chicks . Ducks also exhibit more movement artifacts. polygraph (Fig. 2). All testing was conducted in a Plexiglas testing chamber with temperature and humidity held constant at levels similar to those in the incubator (Fig. 1); The light source was a microscope light placed inside the Plexiglas chamber, approximately 16 cm from the head of the embryo . The light, which F
was aimed at the right eye of the embryo, was filtered through a beaker of copper sulphate solution which absorbed most of the infra-red portion of the light so that after passing through this solution the light had a peak transmittance towards the blue portion of the spectrum . Temperature was monitored by a thermistor
278
ANIMAL BEHAVIOUR, 16, 2-3
probe (painted black for increased light absorption) placed in the direct beam of light. No measurable increase in temperature was recorded under the conditions of illumination . The incident intensity of the light as measured at the eye of the embryo was approximately 1500 ft-candles. After the embryo had been properly exposed and prepared for testing, it was placed in the testing chamber. All testing was done at night with the room lights . off and the testing chamber covered by a piece of black cloth . The embryo was placed in the dark chamber for 30 min before the initiation of testing . Next, 10 min of baseline recording was taken in the dark, and at the end of this 10-min period, the light was turned on for 1 min . Following the I min of illumination an additional 5 min of base line recording was obtained from each embryo . In this way, each embryo served as its own control . There were no extraneous auditory cues to indicate the turning on or off of the light source . At the end of its recording period, each embryo was returned to the incubator and allowed to hatch . All fifty embryos hatched between 12 to 40 hr after testing. Results The results from each embryo are presented in Table I. The recordings were evaluated in terms of the average rate per min of beakclapping. That is, the overall number of beak claps during a specified observation period were divided by the number of minutes in the recording period (10 min, 5 min) . The average base rate for the chick embryos during the initial 10 min of recording in the dark was 19 . 6 per min . During the 1 min of light stimulation, the rate increased to 39 . 1 per min and then decreased to near the base rate (22 . 5 per min) during the final 5 min of recording in the dark. The comparable values for the duck are 37 . 9 (10 min dark), 66 . 1 (1 min light) and 34 . 5 (5 min dark) . The standard deviations for each embryo along with the average standard deviations are also shown in Table I . Using the Wilcoxon matched-pairs signedranks test, the increase in beak-clapping between the base rate (10 min dark) and the I min of light stimulation was found to be significant for both the chicks and the ducks (P<0 .01). Both Pvalues are based on two-tailed tests of significance . Twenty of the twenty-five chicks and twenty of the twenty-five ducks contributed to the increase in beak-clapping rate . The remain-
ing embryos either showed a decrease or no change in beak-clapping rate. The differences between 1 min of light stimulation and 5 min dark were also found to be reliable for both chicks and ducks (P<0 .01). Discussion It seems quite clear from these results that both the chick and duck embryo, at the ages studied, are behaviourally responsive to light stimulation. The present study substantiates the earlier studies of Kuo and Lindeman regarding the presence of light responsivity in the chick embryo . Further studies are under way to determine the earliest time at which this responsivity occurs . The evidence for light responsivity in this investigation was obtained from embryos in which the shell and membranes covering the eye had been removed and in which a relatively intense light stimulus was used . Whether sufficient light penetrates the shell and membranes in the intact egg to stimulate the retina is a question which is in no way answered by this study . However, the ability of chick and duck embryos to respond to light under experimental conditions prior to hatching does provide an opportunity for evaluating the effects of specific embryological stimulation on post-hatching behaviour . It is also of interest to know whether the embryo can respond differentially to various intensities or wavelengths of light since it is known that newlyhatched chicks and ducks are capable of making such discriminations (Hess, 1956 ; Oppenheim, in preparation), and it has been reported since that chick embryos fail to give an ERG response to wavelengths shorter than 510 mµ (PattetaQueriolo & Garcia-Austt, 1956) . Although forty out of fifty embryos in this investigation showed the initial increase in beak-clapping during light stimulation, it is interesting that a few embryos (chick and duck) which were subjected to more than one dark-light-dark sequence seemed to habituate to the light so that after three to four exposures they no longer showed changes in their beak-clapping rate during light stimulation . The author has also observed this rapid habituation of the embryo in response to tactile and proprioceptive stimulation . These casual observations regarding habituation will have to be confirmed by further systematic experiments . In addition, thirteen of the fifty embryos showed an increase rather than a decrease in their beak-clapping rate when the light went off (5 min dark) . It may be that some
OPPENHEIM : LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS PRIOR TO HATCHING
279
Table L Rate of Beak-clapping (per min) In Chick and Dock Embryos before (10 min), during (1 min), and after (5 min) Exposure to Light Stimulation CHICKS Em-
bryo
10 min dark
Age Day
1 min light
Ducxs 5 min dark
10 min dark
Age
Hr
Mean
SID
Mean
Mean
SD
Day Hr
1 min light
5 min dark
Mean
SD
Mean
Mean
SD
1
19
0
5-8
5-6
5.0
7-8
11 . 1
25
6
60-8
16-3
73-0
22-9
8-9
2
19
6
13 . 5
3-2
21-0
9 .0
5-8
25
10
16-6
7-1
8-0
15-3
8-4
3
19
20
26-1
5.1
73-0
21-5
14-6
25
12
23 . 5
2-8
36.0
10-0
9-6
4
19
23
7-4
4-0
25-0
9-2
5-1
26
0
17-3
9.4
12-0
58-5
11-0
5
20
0
7-6
8-5
3-0
8.9
6-1
26
0
35-8
3 .3
55-0
36-4
7.7
6
20
1
23-0
6.8
77-0
19 . 5
5-8
26
2
81-8
30-4
74-0
53-2
29-2
7
20
2
10-7
5-0
59-0
11 .0
7 .9
26
3
33-5
6-6
27-0
31-2
6-0
8
20
3
9.1
5-8
13 .0
21-5
14-0
26
6
14-2
6 .5
21-0
33-0
5-8
9
20
3
19-3
7-3
36-0
11-8
6-3
26
6
28-4
8-2
46.0
20-8
7-7
10
20
3
26-3
6-2
46 .0
27-2
10-7
26
6
36-9
21-9
88 . 0
28-0
12-2
11
20
3
17-5
5-6
9-0
21-0
20-0
26
6
30-0
16-9
54-0
13-0
9-2
12
20
3
17-9
8-5
25-0
28-6
11 . 1
26
7
86-7
14-6
112-0
58-6
17-2
13
20
5
18-3
5.0
59-0
63-6
12-0
26
7
15-5
6-5
35-0
7-0
18-3
14
20
5
14-2
6-0
38-0
9-4
9.1
26
8
33-7
12-5
65-0
25-4
15-2
15
20
6
55-2
7-4
70 . 0
38-6
8-1
26
9
67-8
15-0
104-0
76 . 3
17-9
16
20
6
15-4
12-9
36-0
20-0
9-6
26
9
20-5
11-7
22-0
24 . 0
7-7
17
20
6
30 .0
10-1
55-0
44-2
16-9
26
10
29-2
11-6
51-0
38-2
8-6
18
20
8
21 . 3
8-6
46-0
20-0
13-5
26
11
44-0
29-0
130-0
108-0
29-0
19
20
9
26 . 8
6-2
25-0
16-2
6-3
26
12
9-8
4-6
21-0
16-5
8-0
20
20
9
8 .1
4-8
30-0
13-8
4-4
26
14
44-2
17-3
82-0
23-0
16-2
21
20
10
24-3
5 .4
29-0
25-0
12-9
26
20
10-0
3-6
10 .0
11 .0
4-5
22
20
12
21-3
8-6
46-0
20-0
13 . 5
26
20
34-0
16-2
58-0
22-2
12-6
23
20
13
18-2
9-7
71-0
27-0
10. 1
27
3
67-8
29-0
120-0
65-6
13 . 1
24
20
15
22-5
8-0
31-0
21-0
8-1
27
4
56-8
18-4
150-0
27-1
16-2
25
20
16
31-1
5-0
33-0
37-8
9-8
27
12
48-6
25-1
200-0
37 . 1
23-9
Mean (
20
4
19-6
6-7
39 . 1
22-5
9 .8
26
8
37 . 9
13 . 7
66 . 1
34 . 5
12-9
embryos simply take a longer time to return to the base rate and that with additional recording they also would have exhibited a decrease in their average beak-clapping rate during this time .
Summary Twenty-five chick embryos and twenty-five duck embryos were tested 12 to 40 hr prior to hatching for light responsivity as measured by
2 80
ANIMAL BEHAVIOUR, 16, 2-3
changes in the rate of occurrence of an overt behavioural response (beak-clapping) . The rate of beak-clapping increased significantly in both chicks and ducks during the I min of light stimulation when compared with the base rate of beak-clapping recorded in the dark . Acknowledgments This study was supported by pre-doctoral research fellowship 1-F1-MH-25,937-01 from the Public Health Service . The author would like to thank Gilbert Gottlieb and Viktor Hamburger for critically reading an early draft of the manuscript . REFERENCES Bartley, S . H . (1959) . Central mechanisms of vision . In Handbook of Physiology . pp . 713-740. Section I. Neuro-physiology. Vol. I . (e d . by J . Field, H. W . Magoun and V . E. Hall). Washington, D .C. : American Physiological Society . Coulombre, A . S . (1955) . Correlation of structural and biochemical changes in the developing retina of the chick. Am . J. Anat ., 96, 153-190 . Gottlieb, G . (1965). Prenatal auditory sensitivity in chickens and ducks. Science, 147, 1596-1598 . Hamburger, V . & Hamilton, H. (1951) . A series of normal stages in the development of the chick embryo . J. Morph ., 88,49-92 . Hess, E . H . (1956) . Natural preferences of chicks and ducklings for objects of different colors. Psychol. Rep., 4, 477-483.
Koecke, H. (1958) . Normalstadien der Embryonalentwicklung bei der Hausente . Embryologia, 4, 55-78 . Kuo, Z. Y. (1932) . Ontogeny of embryonic behavior in Aves . I . The chronology and general nature of the behavior of the chick embryo. J. exp. Zool., 61, 395-430. Lindeman, V . F. (1947) . The cholinesterase and acetylcholine content of the chick retina, with special reference to functional activity as indicated by the pupillary constrictor reflex . Am. J. Physiol., 148, 40-44. Patteta-Queriolo, M. A . & Garcia-Austt, E. (1956) . Development of the electroretinogram in the chick embryo. EEG clin . Neurophysiol., 8, 155 . Paulson, G . W. (1965) . Maturation of evoked responses in the duckling . Expl. Neurol., 11, 324-333 . Peters, J. J ., Vonderahe, A. R. & Powers, T . H. (1958). Electrical studies of functional development of the eye and optic lobes in the chick embryo . J. exp . Zool., 139, 459-468 . Rudnick, D . & Waelsch, H . (1955). Development of glutamotransferase and glutamine synthetase in the nervous system of the chick . J. exp . Zool., 129, 309-326. Schifferli, A . (1948) . Ober Markscheidenbildung im Gehirn von Huhn and Star . Rev. Suisse Zool., 55, 117-122. Sechzer, J . A . & Brown, J. L . (1964) . Color discrimination in the cat . Science, 144, 427-429. Shen, S . C ., Greenfield, P . & Boell, E . J. (1956) . Localization of acetylcholinesterase in the chick retina during histogenesis . J. comp . Neurol., 106, 433-461 . Weysse, A . W. & Burgess, W . S . (1906). Histogenesis of the retina . Am. Naturalist, 40, 611-637 . (Received 16 June 1967 ; revised 21 August 1967 ; Ms . number: A596)
LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS JUST PRIOR TO HATCHING BY RONALD W . OPPENHEIM*
Washington University, St Louis, Missouri
The visual systems of chick and duck embryos 1 to 2 days before hatching are morphologically (Weysse & Burgess, 1906 ; Coulombre, 1955 ; Shen et al., 1956 ; Schifferli, 1948), biochemically (Lindeman, 1947 ; Rudnick & Waelsch, 1955), and physiologically (Patteta-Queriolo & GarciaAustt, 1956 ; Peters et al., 1958 ; Paulson, 1965) prepared for their role as a receptor of light stimulation . However, whether the embryo is responsive to visual stimulation remains to be determined, since in the final analysis the question of whether an animal is responsive to specific stimulation has to be settled on the basis of behavioural studies . This point is well exemplified in the case of colour vision in the cat . The cat is known to have the neurophysiological and morphological basis for colour vision . Yet the presence of overt spectral vision (Bartley, 1959) has been exceedingly difficult to demonstrate (Sechzer & Brown, 1964) . Both Lindeman (1948) and Kuo (1932) reported that light stimulation becomes effective in producing an overt response in the chick embryo between 18 and 20 days incubation. Lindeman used the pupillary constriction reflex as an indicator of responsivity, while Kuo used opening and closing of the eyelid as the characteristic embryonic response to light. Although the results obtained by these investigators may be correct, their conclusions that the chick embryo is responsive to light are not supported by the brief and incomplete presentation of the data . Neither investigator established a base rate for the occurrence of the response indicator used (both of these responses occur spontaneously in the absence of any specific introduced stimulation) . The possibility that the responses observed were caused by temperature increases from the light source cannot be eliminated, since these investigators did not consider this variable . In addition, both Kuo and Lindeman failed to utilize appropriate controls (the embryos were not examined in the absence of visual stimula-
tion) or to make any statistical analysis in arriving at their conclusions . In the present study, an attempt was made to re-investigate the visual sensitivity of chick and duck embryos under carefully controlled experimental conditions . Methods Subjects Twenty-five chick embryos from a mixed flock of white leghorn chickens and twenty-five Peking duck embryos (Anas platyrhynchos) were used in this investigation . The eggs were incubated in a large forced-draft incubator with a temperature of 100 ° F and a relative humidity of between 65 to 70 per cent . The ages of the chick embryos at the time of testing ranged from 19 days 0 hr of incubation to 20 days 16 hr with an average age of 20 days 4 hr . The ages of the duck embryos ranged from 25 days 6 hr to 27 days 4 hr with an average of 26 days 8 hr. These ages are comparable to chick stages 44 to 45 (Hamburger & Hamilton, 1951) and duck stages 30 to 31 (Koecke, 1958) . Procedure and Apparatus Prior to testing, the eggs were candled to determine the approximate position of the head, and the shell over this region was then removed. The inner shell membrane, chorio-allantoic membrane and the amniotic sac were then carefully cut and deflected over the head region to expose the beak and right eye (Fig . 1, insert) . The behavioural response used in this investigation was beak-clapping, i .e . the rapid opening and closing of the beak which occurs during the latter one-third of incubation in chick and duck embryos . Changes in the rate of beak-clapping previously have been shown to be a sensitive indicator of auditory responsiveness in chick and duck embryos (Gottlieb, 1965) . Beak-clapping was measured by threading a fine (size 4-0) piece of surgical silk through the loose skin on the ventral side of the lower beak and connecting this to a Linearsyn transducer . This served as a strain gauge which detected all vertical displacements of the lower beak . These movements were then recorded automatically on a Sanborn
*Present address : N.C. Dept. of Mental Health, Division of Research, Neuroembryology Lab., Dorothea Dix Hospital, Raleigh, North Carolina. 276
OPPENHEIM : LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS PRIOR TO HATCHING 277
Fig. 1 . Schematic drawing of Plexiglas testing chamber and recording apparatus . A . light source ; B . copper sulphate solution ; C . duck embryo in egg holder with head exposed ; D. thermistor probe ; E. string attached to embryo's bill passing through hole in testing box ; F . heating unit ; G. fan for circulating heat ; H . strain gauge ; distance between strain gauge and embryo is approximately 30 inches .
Fflosee-+4 A
CHICK 14
Fig. 2. A,, movement artifact ; A, beak-clapping. Quality of beak-clapping is different in the two embryos . The ducks tend to have a more rapid rate of beak-clapping with lower amplitude than the chicks . Ducks also exhibit more movement artifacts. polygraph (Fig. 2). All testing was conducted in a Plexiglas testing chamber with temperature and humidity held constant at levels similar to those in the incubator (Fig. 1); The light source was a microscope light placed inside the Plexiglas chamber, approximately 16 cm from the head of the embryo . The light, which F
was aimed at the right eye of the embryo, was filtered through a beaker of copper sulphate solution which absorbed most of the infra-red portion of the light so that after passing through this solution the light had a peak transmittance towards the blue portion of the spectrum . Temperature was monitored by a thermistor
278
ANIMAL BEHAVIOUR, 16, 2-3
probe (painted black for increased light absorption) placed in the direct beam of light. No measurable increase in temperature was recorded under the conditions of illumination . The incident intensity of the light as measured at the eye of the embryo was approximately 1500 ft-candles. After the embryo had been properly exposed and prepared for testing, it was placed in the testing chamber. All testing was done at night with the room lights . off and the testing chamber covered by a piece of black cloth . The embryo was placed in the dark chamber for 30 min before the initiation of testing . Next, 10 min of baseline recording was taken in the dark, and at the end of this 10-min period, the light was turned on for 1 min . Following the I min of illumination an additional 5 min of base line recording was obtained from each embryo . In this way, each embryo served as its own control . There were no extraneous auditory cues to indicate the turning on or off of the light source . At the end of its recording period, each embryo was returned to the incubator and allowed to hatch . All fifty embryos hatched between 12 to 40 hr after testing. Results The results from each embryo are presented in Table I. The recordings were evaluated in terms of the average rate per min of beakclapping. That is, the overall number of beak claps during a specified observation period were divided by the number of minutes in the recording period (10 min, 5 min) . The average base rate for the chick embryos during the initial 10 min of recording in the dark was 19 . 6 per min . During the 1 min of light stimulation, the rate increased to 39 . 1 per min and then decreased to near the base rate (22 . 5 per min) during the final 5 min of recording in the dark. The comparable values for the duck are 37 . 9 (10 min dark), 66 . 1 (1 min light) and 34 . 5 (5 min dark) . The standard deviations for each embryo along with the average standard deviations are also shown in Table I . Using the Wilcoxon matched-pairs signedranks test, the increase in beak-clapping between the base rate (10 min dark) and the I min of light stimulation was found to be significant for both the chicks and the ducks (P<0 .01). Both Pvalues are based on two-tailed tests of significance . Twenty of the twenty-five chicks and twenty of the twenty-five ducks contributed to the increase in beak-clapping rate . The remain-
ing embryos either showed a decrease or no change in beak-clapping rate. The differences between 1 min of light stimulation and 5 min dark were also found to be reliable for both chicks and ducks (P<0 .01). Discussion It seems quite clear from these results that both the chick and duck embryo, at the ages studied, are behaviourally responsive to light stimulation. The present study substantiates the earlier studies of Kuo and Lindeman regarding the presence of light responsivity in the chick embryo . Further studies are under way to determine the earliest time at which this responsivity occurs . The evidence for light responsivity in this investigation was obtained from embryos in which the shell and membranes covering the eye had been removed and in which a relatively intense light stimulus was used . Whether sufficient light penetrates the shell and membranes in the intact egg to stimulate the retina is a question which is in no way answered by this study . However, the ability of chick and duck embryos to respond to light under experimental conditions prior to hatching does provide an opportunity for evaluating the effects of specific embryological stimulation on post-hatching behaviour . It is also of interest to know whether the embryo can respond differentially to various intensities or wavelengths of light since it is known that newlyhatched chicks and ducks are capable of making such discriminations (Hess, 1956 ; Oppenheim, in preparation), and it has been reported since that chick embryos fail to give an ERG response to wavelengths shorter than 510 mµ (PattetaQueriolo & Garcia-Austt, 1956) . Although forty out of fifty embryos in this investigation showed the initial increase in beak-clapping during light stimulation, it is interesting that a few embryos (chick and duck) which were subjected to more than one dark-light-dark sequence seemed to habituate to the light so that after three to four exposures they no longer showed changes in their beak-clapping rate during light stimulation . The author has also observed this rapid habituation of the embryo in response to tactile and proprioceptive stimulation . These casual observations regarding habituation will have to be confirmed by further systematic experiments . In addition, thirteen of the fifty embryos showed an increase rather than a decrease in their beak-clapping rate when the light went off (5 min dark) . It may be that some
OPPENHEIM : LIGHT RESPONSIVITY IN CHICK AND DUCK EMBRYOS PRIOR TO HATCHING
279
Table L Rate of Beak-clapping (per min) In Chick and Dock Embryos before (10 min), during (1 min), and after (5 min) Exposure to Light Stimulation CHICKS Em-
bryo
10 min dark
Age Day
1 min light
Ducxs 5 min dark
10 min dark
Age
Hr
Mean
SID
Mean
Mean
SD
Day Hr
1 min light
5 min dark
Mean
SD
Mean
Mean
SD
1
19
0
5-8
5-6
5.0
7-8
11 . 1
25
6
60-8
16-3
73-0
22-9
8-9
2
19
6
13 . 5
3-2
21-0
9 .0
5-8
25
10
16-6
7-1
8-0
15-3
8-4
3
19
20
26-1
5.1
73-0
21-5
14-6
25
12
23 . 5
2-8
36.0
10-0
9-6
4
19
23
7-4
4-0
25-0
9-2
5-1
26
0
17-3
9.4
12-0
58-5
11-0
5
20
0
7-6
8-5
3-0
8.9
6-1
26
0
35-8
3 .3
55-0
36-4
7.7
6
20
1
23-0
6.8
77-0
19 . 5
5-8
26
2
81-8
30-4
74-0
53-2
29-2
7
20
2
10-7
5-0
59-0
11 .0
7 .9
26
3
33-5
6-6
27-0
31-2
6-0
8
20
3
9.1
5-8
13 .0
21-5
14-0
26
6
14-2
6 .5
21-0
33-0
5-8
9
20
3
19-3
7-3
36-0
11-8
6-3
26
6
28-4
8-2
46.0
20-8
7-7
10
20
3
26-3
6-2
46 .0
27-2
10-7
26
6
36-9
21-9
88 . 0
28-0
12-2
11
20
3
17-5
5-6
9-0
21-0
20-0
26
6
30-0
16-9
54-0
13-0
9-2
12
20
3
17-9
8-5
25-0
28-6
11 . 1
26
7
86-7
14-6
112-0
58-6
17-2
13
20
5
18-3
5.0
59-0
63-6
12-0
26
7
15-5
6-5
35-0
7-0
18-3
14
20
5
14-2
6-0
38-0
9-4
9.1
26
8
33-7
12-5
65-0
25-4
15-2
15
20
6
55-2
7-4
70 . 0
38-6
8-1
26
9
67-8
15-0
104-0
76 . 3
17-9
16
20
6
15-4
12-9
36-0
20-0
9-6
26
9
20-5
11-7
22-0
24 . 0
7-7
17
20
6
30 .0
10-1
55-0
44-2
16-9
26
10
29-2
11-6
51-0
38-2
8-6
18
20
8
21 . 3
8-6
46-0
20-0
13-5
26
11
44-0
29-0
130-0
108-0
29-0
19
20
9
26 . 8
6-2
25-0
16-2
6-3
26
12
9-8
4-6
21-0
16-5
8-0
20
20
9
8 .1
4-8
30-0
13-8
4-4
26
14
44-2
17-3
82-0
23-0
16-2
21
20
10
24-3
5 .4
29-0
25-0
12-9
26
20
10-0
3-6
10 .0
11 .0
4-5
22
20
12
21-3
8-6
46-0
20-0
13 . 5
26
20
34-0
16-2
58-0
22-2
12-6
23
20
13
18-2
9-7
71-0
27-0
10. 1
27
3
67-8
29-0
120-0
65-6
13 . 1
24
20
15
22-5
8-0
31-0
21-0
8-1
27
4
56-8
18-4
150-0
27-1
16-2
25
20
16
31-1
5-0
33-0
37-8
9-8
27
12
48-6
25-1
200-0
37 . 1
23-9
Mean (
20
4
19-6
6-7
39 . 1
22-5
9 .8
26
8
37 . 9
13 . 7
66 . 1
34 . 5
12-9
embryos simply take a longer time to return to the base rate and that with additional recording they also would have exhibited a decrease in their average beak-clapping rate during this time .
Summary Twenty-five chick embryos and twenty-five duck embryos were tested 12 to 40 hr prior to hatching for light responsivity as measured by
2 80
ANIMAL BEHAVIOUR, 16, 2-3
changes in the rate of occurrence of an overt behavioural response (beak-clapping) . The rate of beak-clapping increased significantly in both chicks and ducks during the I min of light stimulation when compared with the base rate of beak-clapping recorded in the dark . Acknowledgments This study was supported by pre-doctoral research fellowship 1-F1-MH-25,937-01 from the Public Health Service . The author would like to thank Gilbert Gottlieb and Viktor Hamburger for critically reading an early draft of the manuscript . REFERENCES Bartley, S . H . (1959) . Central mechanisms of vision . In Handbook of Physiology . pp . 713-740. Section I. Neuro-physiology. Vol. I . (e d . by J . Field, H. W . Magoun and V . E. Hall). Washington, D .C. : American Physiological Society . Coulombre, A . S . (1955) . Correlation of structural and biochemical changes in the developing retina of the chick. Am . J. Anat ., 96, 153-190 . Gottlieb, G . (1965). Prenatal auditory sensitivity in chickens and ducks. Science, 147, 1596-1598 . Hamburger, V . & Hamilton, H. (1951) . A series of normal stages in the development of the chick embryo . J. Morph ., 88,49-92 . Hess, E . H . (1956) . Natural preferences of chicks and ducklings for objects of different colors. Psychol. Rep., 4, 477-483.
Koecke, H. (1958) . Normalstadien der Embryonalentwicklung bei der Hausente . Embryologia, 4, 55-78 . Kuo, Z. Y. (1932) . Ontogeny of embryonic behavior in Aves . I . The chronology and general nature of the behavior of the chick embryo. J. exp. Zool., 61, 395-430. Lindeman, V . F. (1947) . The cholinesterase and acetylcholine content of the chick retina, with special reference to functional activity as indicated by the pupillary constrictor reflex . Am. J. Physiol., 148, 40-44. Patteta-Queriolo, M. A . & Garcia-Austt, E. (1956) . Development of the electroretinogram in the chick embryo. EEG clin . Neurophysiol., 8, 155 . Paulson, G . W. (1965) . Maturation of evoked responses in the duckling . Expl. Neurol., 11, 324-333 . Peters, J. J ., Vonderahe, A. R. & Powers, T . H. (1958). Electrical studies of functional development of the eye and optic lobes in the chick embryo . J. exp . Zool., 139, 459-468 . Rudnick, D . & Waelsch, H . (1955). Development of glutamotransferase and glutamine synthetase in the nervous system of the chick . J. exp . Zool., 129, 309-326. Schifferli, A . (1948) . Ober Markscheidenbildung im Gehirn von Huhn and Star . Rev. Suisse Zool., 55, 117-122. Sechzer, J . A . & Brown, J. L . (1964) . Color discrimination in the cat . Science, 144, 427-429. Shen, S . C ., Greenfield, P . & Boell, E . J. (1956) . Localization of acetylcholinesterase in the chick retina during histogenesis . J. comp . Neurol., 106, 433-461 . Weysse, A . W. & Burgess, W . S . (1906). Histogenesis of the retina . Am. Naturalist, 40, 611-637 . (Received 16 June 1967 ; revised 21 August 1967 ; Ms . number: A596)