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Heart beat frequency variations in the moth Mamestra brassicae during ontogeny
3. Insect Physiol., 1972, Vol. 18, pp. 1739to 1744. Pergmon
Press. printed in Grmt Britain
HEART BEAT FREQUENCY VARIATIONS IN THE MOTH MAMESTRA 23R4SSICAE DURING ONTOGENY YVON QUEINNEC Laboratoire
and RAYMOND
CAMPAN
de Psychophysiologie, U.E.R. de Biologie Exp&irnentale, P. Sabatier, 31-Toulouse, France (Received 26 April 1971; revised 28 February
Univeraiti
1972)
Abstract-Records of the heart rate are made by implanting steel electrodes on intact fixed animals. Larvae and pharate pupae present one-directional pulsation waves; in old pharate pupae reversals begin and occur throughout the pharate adult stage. The heart beat frequency steadily decreases all through larval, pharate pupal, and the beginning of the pharate adult stages. Before adult emergence a marked tachycardy occurs. In adults the periodical frequency variation does not depend upon reversals. INTRODUCTION THE PHYSIOUX;Y
of the insect heart still raises many queations although the first studies are three centuries old (HARVEY,1628; MALPIGHI, 1669). In the past ten years, two reviews (JONES, 1964; MCCANN, 1970) have emphasized the lack of precision about heart frequency variations during larval, pupal, and adult development. On the other hand, the appearance, in some stages, of normal heart beat reversals (changes in the direction of the contraction waves) remains uncertain. There are only a few studies (NEWPORT, 1836; Massnu, 1936; JONES, 1956; SOANSand SOANS, 1968; ROW=, 1969; GHIASUDDINand NAIDU, 1970) dealing with cardiac variations during life; most authors have observed only a restricted number of developmental stages. Nevertheless, an investigation of heart rate is of great interest in relation to changes in developmental physiology. Results presented here reveal a decline of the heart rate during larval life and Some critical periods are clearly pointed out. Hearts of old metamorphosis. pharate pupae and pharate adults periodically exhibit reversals in beat direction. The duration of backward and forward contraction phases varies throughout all the pharate adult period. Adults show periodical changes in heart frequency without reversals. MATERIALS
AND METHODS
In this experiment we have tested 120 larvae, 30 pharate pupae, 58 pharate adults, and 33 emerged adults (11 females and 22 males) of the cabbage moth Mamestru (Bmuthra) bmssicae L. The animals were bred in a constant temperature room (18 + 1’C). To describe the different stages of insect development the terminology 1739
1740
YVON QU~INNECAND RAYMOND
CAMPAN
used is a histological one (HINTON, 1971) so the term ‘pharate pupae’ (HINTON, 1946) is referred to the animal after larval-pupal apolysis, a 5-day-long period between the end of the feeding phase of the sixth larvae and the larvalpupal ecdysis. The pharate adult refers to the adult still enclosed within the pupal cuticle. We say ‘old pharate pupae’ for individuals 1 day before ecdysis ; young males and females are 3 days after emergence, old males are 10 days after emergence. Electrocardiographic records (EKG) were made on larvae (stages I to VI), pharate pupae (young and old), pharate adults (throughout metamorphosis) and emerged adults (young females, young and old males). The anatomy of the dorsal vessel is simple. Larvae have a straight tube without diverticula; the abdominal part has a series of segmental saclike dilatations (heart chambers) ; the thoracic part or aorta is unchambered. The adult heart is comparable to the larval one ; the aorta running from the abdominal heart to the head presents an arrangement including a mesothoracic dorsal vertical chamber with meta- and prothoracic . branches (-EL, 1966). Heart potentials were recorded from the hearts of intact but immobilized individuals using steel electrodes ; the records were subsequently amplified and registered on a pen-recorder (ALVAR Praxigraph XI). Continuous visual observations were made with a TEKTRONIX 502 A Oscilloscope. The movements of the heart observed through the transparent integument coincide with the polygraph records. In some adults two pairs of electrodes were implanted; the first one was placed in the mesothorax and the second in the segments of the middle of the abdomen. We took the first heart recording 30 min after implanting electrodes and a second one 15 min later. RESULTS Within a given instar, the larvae from the first to the last stage (stage VI) as well as pharate pupae exhibited a steady heart rate without reversals: the haemolymph was always pulsed forward from the abdominal end to the head. Heart beat frequency during the course of larval life steadily decreased from 82.8 beats/ min in newly eclosed larvae to 44.6 beatsfmin at the end of the feeding period (Fig. 1). A large frequency decrease occurred following the food intake of the first stage larvae; a marked slowing occurred during pharate pupal life (resting time during cocoon spinning). These results are in good agreement with those found in Sphinx (NEWWRT, 1836), Bombyx (MASS, 1936), Anopheles (JONES, 1956), Ctin&Zlu (SOANS and SOANS, 1968) and Locusta (Roussa, 1969) larvae and/or adults. Temperature increase induced a significant shift of the heart rate values to higher frequencies (Fig. 1); these results are in good agreement with those given by many authors {e.g. FRIES, 1926; RICIMIDS, 1963; ROUSSEL,1969). In the pharate pupae reaching the larval-pupal ecdysis as well as in pharate adults, periodic variations appear in the direction of haemolymph propagation in the dorsal vessel: rather high frequency beats (forward pulsations) regularly
HEART EzEATFREQUENCY VARIATIONS W MAMESTRA
1741
BRASSICAE
alternated with lower frequency beata (backward pulsations). Four sets of data were used to study this alternating rhythm and its ontogenetic changes (Table 1). The fast phase frequency was low during the early part of the pharate adult stage (29.56 beatalmin), and remained constant during the first two-thirds of this
lls Phamte pupae
Phamte
Adult
adult
1. Heart beat frequency evolution veraus developmental stages. The temperature efiect is atresaed by the comparison between the cross (27°C) and black circles (22°C) plotted lines. The rate of the one-directional pulsations decreases during the larval period. The white circles indicate the appearance and variation of the fast phaae frequency of the double rhythm with reversals. The values of the frequency of the feet phase in adult one directional rhythm are plotted with white triangles. LP = larval-pupal ecdysia; PA = pupal-adult ecdysis. The dispersion index indicates + 1 standard error about the average. TABLE
~--CI.IARAC~ERISTICS
Stages Old pharate pupae 3 days after larval-pupal ecdysis Middle-stage pharate adult Pharate adult close to emergence Young females Young males Old males
OF SLOW AND FAST WEAR-r RATES
Frequency (beats/mm)
Mean duration fast phase (F.P.) (set)
Mean duration slow phase (S-P.) (set)
Ratio S.P.1F.P.
28.1 + 2.21
127.2 & 30.17
232 + 32.76
2.04
29.5 f 1.22 28-2 f 1.24 56*1+- 6-O 88.6 f 6.53 86.7 f 5.99 74.7 f 5.30
394.5 f. 107.20 928.45 118.83 135.0 + 32.65 104.5 & 6.76 106.0 +- 12.26 124.9 + 9.51
238.7 661.7 116.0 41.5 29.6 37.7
+ 75.99 + 110.24 +132-W f3.80 + 0.83 + 0.58
0.60 0.89 0.86 0.39 0.28 0.30
1742
YVON
QUEINNEC AND
RAYMOND
CAMPAN
period (28.2 beats/mm). A marked frequency increase occurred during the last part of the pupal stage, up to 75 beats/min just before adult emergence. The alternating fast-slow beating varied during the pharate adult time, although rather fast at first it strongly decreased in the middle of this stage. It then became very fast again close to the pupal-adult ecdysis. The proportion of the slow phase duration over the fast phase duration was relatively small at the beginning of the pharate adult stage, then strongly increased in the middle part and finally decreased. C I
B I
A 100
!
IF
(a)
90
&dN
SO-
I-
v
:
:
If-rrri-, ,
2mv Number
of contmctions.
Jbeats per bbck
4
I
h
I
?‘
FIG. 2. Frequency variation during slow and fast phases in young adults. Each point of the curve is corresponding to the mean frequency of five consecutive cardiac cycles. The spe&c times of the records are indicated by corresponding letters. On each record the upper trace is picked up in the thorax and the lower one in the abdominal segments. The abdominal potentials are always slightly delayed.
In the emerged adult the regular alternation of fast and slow beating phases persisted (Fig. 2), but we have never been able to see backward contractions. The analysis of records with two pairs of electrodes (Fig. 2) enabled us to demonstrate that the depolarization wave runs forward along the dorsal vessel at any frequency. The propagation speed of the wave is about 17.5-20 mm/set according to the results of TENNEY (1953) in the moth TeleapoZyphemus and those of HECHT (1918) in the ascidian tubular heart. Nevertheless, some short and irregular reversals were sometimes recorded. There are no significant differences between the heart characteristics of females and males. During ageing, adult males showed a slight heart beat frequency decrease, with a lengthening of the fast phase duration so that the number of beats during a fast phase remained quite constant (mean values: young females = 153.6, young males = 153.8, old males = 154.8 beats/fast phase). In conclusion, the main features of the ontogenetic evolution of the heart activity in M. bras&m are: (a) heart-rate decrease in the course of larval and
HEARTBEATFREQU’l3NCY VARIATIONS IN MAMESTRA
Z3ZtASSZCAZi
1743
pharate pupal stages; (b) occurrence, during metamorphosis, of regular heart-beat reversals associated with two different frequency values. This process is possibly related to the cardiac restructuring described in Lepidoptera, particularly to the histolysis of the hind regions (GEROULD,1938); (c) persistence of two frequencies in adults, but in this case the haemolymph circulation always remains anterograde, and does not periodically reverse.
Nous avons effectue l’enregistrement de l’activite &ctrique du tube cardiaque, par implantation d’une paire d’&ctrodes d’acier a&&s par &ctrolyse, chex des individus appartenant aux d&rents stades du developpement de la noctuelle du thou. Les larves pr&entent des ondes de contraction se pmpageant toujours de la partie poat&ieure de I’abdomen vers la t&e, le long du vaiaseau dorsal. Mais peu avant la nymphale on mue observe un double rythme avec altemance r&uliere d’ondes cimulant aoit de la r&ion cephalo-thoracique vers la partie posterieure abdominale (ondes retrogrades) aoit en sens inverse (conduction antemgrade). Cette altemance du aens de propagation des ondes de contraction cardiaque peraiste pendant toute la vie de la pupe. Chez les larves et d&s le debut de la m&amorphose la fr&quence cardiaque d&mlt r&uli&ement. Une forte tachycardie apparait avant la mue imagmale et peraiate chez l’adulte au moins pendant les phases dims de rythme rapide. En &et le rythme cardiaque de l’adulte pr&ente une recurrence de phases ir frequence Clew& et de phases & fr&uence relativement basse. Cette alternance de rythmes de frcquences di!%rentes ne s’accompagne pas, dans ce cas, de modification dans le sens de pmpagation de l’onde de contraction qui est toujours antCmgrade. Cela a Ctc coniirrn~ par I’analyae des enregistrements efIectu4s en implantant chez des adultes deux paires d’hlectrodes: une paire dans le m&aothorax et une autre dans l’abdomen. REFERENCES FRIES E. F. B. (1926) Temperature and frequency of heart beat in the cockroach. J. gen. Phyti. 10, 227-237. GEROULDJ. H. (1938) Structure and action of the heart of BOW&Wmti and other insects. Acta Zool. 19, 297-352. GHIA.WDDINS. M. and NAIDU M. B. (1970) Heart-beat frequency of American co&roach, Periplaneta americana (L.) with reference to age and sex. J. anim. Murph. Physiol. 17,137-145. HARVEVW. (1628) Exercitatio Anatomica de Moto Cordis et Sanguinis in Animalibus, Sumptibus Guilielini Fitzeri, Francofurti. HECHT S. (1918) The physiology of Ascidia atria Lesueur-XII. The blood system. Am. J. Physiol. 45, 157-187. HEZXEL J. H. (1966) A prehminary comparative anatomical study of the mesothoracic aorta of the Lepidoptera. Ann. ent. Sot. Am. 59,1217-1227. HINTON H. E. (1946) Concealed phases in the metamorphosis of insects. Nature, Land. 157, 552-553. HINTON H. E. (1971) Some neglected phases in the metamorphosis. PYOC. R. ent. Sot. Land. (C) 35, 55-64. JONES J. C. (1956) A study of normal heart rates in intact Anopheles quadkacsdat~s Say larvae. J. exp. ZooI. 131, 223-233. JONES J. C. (1964) The circulatory system of insects. In Physiology of Insecta (Ed. by RWK~TEIN M.), 3, l-107. Academic Press, New York. MCCANN F. V. (1970) Physiology of insect hearts. A. Rev. Ent. 15,173-200.
1744
YVON
QVHNNECAND RAYMONDCAMP-
MALPICHI M. (1669) Dksertutio Epistolicu de Bombyce. J. Martyn et J. Ahestry, Londini. MMBRA E. (1936) 11 ritmo de1 vaso puIsante ai phenomeni respiratori e di accrescimento nel Bombyx 1110+3 L. Ann. R. Stux. Baco. Splrinr. Padova 48,313-320. NBWPORTG. (1836-1839) Insecta. In The Cyc&wedia of Anutomy and PhysioZogy (Ed. by TODD R. B.), 2.853-994. Longmans, London. RICHARDSA. G. (1963) The e&t of temperature on heart-beat frequency in the cockroach,
Periplaneta americana. J. Insect Phytiol. 9, 597606. ROUSSBLJ. P. (1969) Le rythme cardiaque chez Locusta migratork. Bull. Sot. 2001. FT. 94, 677-695. SOANSA. B. and SOANSJ. S. (1968) Observations on the rate of heart beat in the various stages of the tiger beetle, Ct&dello cancel&a Dej. Cum. 5%. Indin 37, 108. TENNEYS. M. (1953) Observations on the physiology of the lepidopteran heart with special reference to revetsal of the beat. Physiol. Camp. Oecol. 3,286-306.
Press. printed in Grmt Britain
HEART BEAT FREQUENCY VARIATIONS IN THE MOTH MAMESTRA 23R4SSICAE DURING ONTOGENY YVON QUEINNEC Laboratoire
and RAYMOND
CAMPAN
de Psychophysiologie, U.E.R. de Biologie Exp&irnentale, P. Sabatier, 31-Toulouse, France (Received 26 April 1971; revised 28 February
Univeraiti
1972)
Abstract-Records of the heart rate are made by implanting steel electrodes on intact fixed animals. Larvae and pharate pupae present one-directional pulsation waves; in old pharate pupae reversals begin and occur throughout the pharate adult stage. The heart beat frequency steadily decreases all through larval, pharate pupal, and the beginning of the pharate adult stages. Before adult emergence a marked tachycardy occurs. In adults the periodical frequency variation does not depend upon reversals. INTRODUCTION THE PHYSIOUX;Y
of the insect heart still raises many queations although the first studies are three centuries old (HARVEY,1628; MALPIGHI, 1669). In the past ten years, two reviews (JONES, 1964; MCCANN, 1970) have emphasized the lack of precision about heart frequency variations during larval, pupal, and adult development. On the other hand, the appearance, in some stages, of normal heart beat reversals (changes in the direction of the contraction waves) remains uncertain. There are only a few studies (NEWPORT, 1836; Massnu, 1936; JONES, 1956; SOANSand SOANS, 1968; ROW=, 1969; GHIASUDDINand NAIDU, 1970) dealing with cardiac variations during life; most authors have observed only a restricted number of developmental stages. Nevertheless, an investigation of heart rate is of great interest in relation to changes in developmental physiology. Results presented here reveal a decline of the heart rate during larval life and Some critical periods are clearly pointed out. Hearts of old metamorphosis. pharate pupae and pharate adults periodically exhibit reversals in beat direction. The duration of backward and forward contraction phases varies throughout all the pharate adult period. Adults show periodical changes in heart frequency without reversals. MATERIALS
AND METHODS
In this experiment we have tested 120 larvae, 30 pharate pupae, 58 pharate adults, and 33 emerged adults (11 females and 22 males) of the cabbage moth Mamestru (Bmuthra) bmssicae L. The animals were bred in a constant temperature room (18 + 1’C). To describe the different stages of insect development the terminology 1739
1740
YVON QU~INNECAND RAYMOND
CAMPAN
used is a histological one (HINTON, 1971) so the term ‘pharate pupae’ (HINTON, 1946) is referred to the animal after larval-pupal apolysis, a 5-day-long period between the end of the feeding phase of the sixth larvae and the larvalpupal ecdysis. The pharate adult refers to the adult still enclosed within the pupal cuticle. We say ‘old pharate pupae’ for individuals 1 day before ecdysis ; young males and females are 3 days after emergence, old males are 10 days after emergence. Electrocardiographic records (EKG) were made on larvae (stages I to VI), pharate pupae (young and old), pharate adults (throughout metamorphosis) and emerged adults (young females, young and old males). The anatomy of the dorsal vessel is simple. Larvae have a straight tube without diverticula; the abdominal part has a series of segmental saclike dilatations (heart chambers) ; the thoracic part or aorta is unchambered. The adult heart is comparable to the larval one ; the aorta running from the abdominal heart to the head presents an arrangement including a mesothoracic dorsal vertical chamber with meta- and prothoracic . branches (-EL, 1966). Heart potentials were recorded from the hearts of intact but immobilized individuals using steel electrodes ; the records were subsequently amplified and registered on a pen-recorder (ALVAR Praxigraph XI). Continuous visual observations were made with a TEKTRONIX 502 A Oscilloscope. The movements of the heart observed through the transparent integument coincide with the polygraph records. In some adults two pairs of electrodes were implanted; the first one was placed in the mesothorax and the second in the segments of the middle of the abdomen. We took the first heart recording 30 min after implanting electrodes and a second one 15 min later. RESULTS Within a given instar, the larvae from the first to the last stage (stage VI) as well as pharate pupae exhibited a steady heart rate without reversals: the haemolymph was always pulsed forward from the abdominal end to the head. Heart beat frequency during the course of larval life steadily decreased from 82.8 beats/ min in newly eclosed larvae to 44.6 beatsfmin at the end of the feeding period (Fig. 1). A large frequency decrease occurred following the food intake of the first stage larvae; a marked slowing occurred during pharate pupal life (resting time during cocoon spinning). These results are in good agreement with those found in Sphinx (NEWWRT, 1836), Bombyx (MASS, 1936), Anopheles (JONES, 1956), Ctin&Zlu (SOANS and SOANS, 1968) and Locusta (Roussa, 1969) larvae and/or adults. Temperature increase induced a significant shift of the heart rate values to higher frequencies (Fig. 1); these results are in good agreement with those given by many authors {e.g. FRIES, 1926; RICIMIDS, 1963; ROUSSEL,1969). In the pharate pupae reaching the larval-pupal ecdysis as well as in pharate adults, periodic variations appear in the direction of haemolymph propagation in the dorsal vessel: rather high frequency beats (forward pulsations) regularly
HEART EzEATFREQUENCY VARIATIONS W MAMESTRA
1741
BRASSICAE
alternated with lower frequency beata (backward pulsations). Four sets of data were used to study this alternating rhythm and its ontogenetic changes (Table 1). The fast phase frequency was low during the early part of the pharate adult stage (29.56 beatalmin), and remained constant during the first two-thirds of this
lls Phamte pupae
Phamte
Adult
adult
1. Heart beat frequency evolution veraus developmental stages. The temperature efiect is atresaed by the comparison between the cross (27°C) and black circles (22°C) plotted lines. The rate of the one-directional pulsations decreases during the larval period. The white circles indicate the appearance and variation of the fast phaae frequency of the double rhythm with reversals. The values of the frequency of the feet phase in adult one directional rhythm are plotted with white triangles. LP = larval-pupal ecdysia; PA = pupal-adult ecdysis. The dispersion index indicates + 1 standard error about the average. TABLE
~--CI.IARAC~ERISTICS
Stages Old pharate pupae 3 days after larval-pupal ecdysis Middle-stage pharate adult Pharate adult close to emergence Young females Young males Old males
OF SLOW AND FAST WEAR-r RATES
Frequency (beats/mm)
Mean duration fast phase (F.P.) (set)
Mean duration slow phase (S-P.) (set)
Ratio S.P.1F.P.
28.1 + 2.21
127.2 & 30.17
232 + 32.76
2.04
29.5 f 1.22 28-2 f 1.24 56*1+- 6-O 88.6 f 6.53 86.7 f 5.99 74.7 f 5.30
394.5 f. 107.20 928.45 118.83 135.0 + 32.65 104.5 & 6.76 106.0 +- 12.26 124.9 + 9.51
238.7 661.7 116.0 41.5 29.6 37.7
+ 75.99 + 110.24 +132-W f3.80 + 0.83 + 0.58
0.60 0.89 0.86 0.39 0.28 0.30
1742
YVON
QUEINNEC AND
RAYMOND
CAMPAN
period (28.2 beats/mm). A marked frequency increase occurred during the last part of the pupal stage, up to 75 beats/min just before adult emergence. The alternating fast-slow beating varied during the pharate adult time, although rather fast at first it strongly decreased in the middle of this stage. It then became very fast again close to the pupal-adult ecdysis. The proportion of the slow phase duration over the fast phase duration was relatively small at the beginning of the pharate adult stage, then strongly increased in the middle part and finally decreased. C I
B I
A 100
!
IF
(a)
90
&dN
SO-
I-
v
:
:
If-rrri-, ,
2mv Number
of contmctions.
Jbeats per bbck
4
I
h
I
?‘
FIG. 2. Frequency variation during slow and fast phases in young adults. Each point of the curve is corresponding to the mean frequency of five consecutive cardiac cycles. The spe&c times of the records are indicated by corresponding letters. On each record the upper trace is picked up in the thorax and the lower one in the abdominal segments. The abdominal potentials are always slightly delayed.
In the emerged adult the regular alternation of fast and slow beating phases persisted (Fig. 2), but we have never been able to see backward contractions. The analysis of records with two pairs of electrodes (Fig. 2) enabled us to demonstrate that the depolarization wave runs forward along the dorsal vessel at any frequency. The propagation speed of the wave is about 17.5-20 mm/set according to the results of TENNEY (1953) in the moth TeleapoZyphemus and those of HECHT (1918) in the ascidian tubular heart. Nevertheless, some short and irregular reversals were sometimes recorded. There are no significant differences between the heart characteristics of females and males. During ageing, adult males showed a slight heart beat frequency decrease, with a lengthening of the fast phase duration so that the number of beats during a fast phase remained quite constant (mean values: young females = 153.6, young males = 153.8, old males = 154.8 beats/fast phase). In conclusion, the main features of the ontogenetic evolution of the heart activity in M. bras&m are: (a) heart-rate decrease in the course of larval and
HEARTBEATFREQU’l3NCY VARIATIONS IN MAMESTRA
Z3ZtASSZCAZi
1743
pharate pupal stages; (b) occurrence, during metamorphosis, of regular heart-beat reversals associated with two different frequency values. This process is possibly related to the cardiac restructuring described in Lepidoptera, particularly to the histolysis of the hind regions (GEROULD,1938); (c) persistence of two frequencies in adults, but in this case the haemolymph circulation always remains anterograde, and does not periodically reverse.
Nous avons effectue l’enregistrement de l’activite &ctrique du tube cardiaque, par implantation d’une paire d’&ctrodes d’acier a&&s par &ctrolyse, chex des individus appartenant aux d&rents stades du developpement de la noctuelle du thou. Les larves pr&entent des ondes de contraction se pmpageant toujours de la partie poat&ieure de I’abdomen vers la t&e, le long du vaiaseau dorsal. Mais peu avant la nymphale on mue observe un double rythme avec altemance r&uliere d’ondes cimulant aoit de la r&ion cephalo-thoracique vers la partie posterieure abdominale (ondes retrogrades) aoit en sens inverse (conduction antemgrade). Cette altemance du aens de propagation des ondes de contraction cardiaque peraiste pendant toute la vie de la pupe. Chez les larves et d&s le debut de la m&amorphose la fr&quence cardiaque d&mlt r&uli&ement. Une forte tachycardie apparait avant la mue imagmale et peraiate chez l’adulte au moins pendant les phases dims de rythme rapide. En &et le rythme cardiaque de l’adulte pr&ente une recurrence de phases ir frequence Clew& et de phases & fr&uence relativement basse. Cette alternance de rythmes de frcquences di!%rentes ne s’accompagne pas, dans ce cas, de modification dans le sens de pmpagation de l’onde de contraction qui est toujours antCmgrade. Cela a Ctc coniirrn~ par I’analyae des enregistrements efIectu4s en implantant chez des adultes deux paires d’hlectrodes: une paire dans le m&aothorax et une autre dans l’abdomen. REFERENCES FRIES E. F. B. (1926) Temperature and frequency of heart beat in the cockroach. J. gen. Phyti. 10, 227-237. GEROULDJ. H. (1938) Structure and action of the heart of BOW&Wmti and other insects. Acta Zool. 19, 297-352. GHIA.WDDINS. M. and NAIDU M. B. (1970) Heart-beat frequency of American co&roach, Periplaneta americana (L.) with reference to age and sex. J. anim. Murph. Physiol. 17,137-145. HARVEVW. (1628) Exercitatio Anatomica de Moto Cordis et Sanguinis in Animalibus, Sumptibus Guilielini Fitzeri, Francofurti. HECHT S. (1918) The physiology of Ascidia atria Lesueur-XII. The blood system. Am. J. Physiol. 45, 157-187. HEZXEL J. H. (1966) A prehminary comparative anatomical study of the mesothoracic aorta of the Lepidoptera. Ann. ent. Sot. Am. 59,1217-1227. HINTON H. E. (1946) Concealed phases in the metamorphosis of insects. Nature, Land. 157, 552-553. HINTON H. E. (1971) Some neglected phases in the metamorphosis. PYOC. R. ent. Sot. Land. (C) 35, 55-64. JONES J. C. (1956) A study of normal heart rates in intact Anopheles quadkacsdat~s Say larvae. J. exp. ZooI. 131, 223-233. JONES J. C. (1964) The circulatory system of insects. In Physiology of Insecta (Ed. by RWK~TEIN M.), 3, l-107. Academic Press, New York. MCCANN F. V. (1970) Physiology of insect hearts. A. Rev. Ent. 15,173-200.
1744
YVON
QVHNNECAND RAYMONDCAMP-
MALPICHI M. (1669) Dksertutio Epistolicu de Bombyce. J. Martyn et J. Ahestry, Londini. MMBRA E. (1936) 11 ritmo de1 vaso puIsante ai phenomeni respiratori e di accrescimento nel Bombyx 1110+3 L. Ann. R. Stux. Baco. Splrinr. Padova 48,313-320. NBWPORTG. (1836-1839) Insecta. In The Cyc&wedia of Anutomy and PhysioZogy (Ed. by TODD R. B.), 2.853-994. Longmans, London. RICHARDSA. G. (1963) The e&t of temperature on heart-beat frequency in the cockroach,
Periplaneta americana. J. Insect Phytiol. 9, 597606. ROUSSBLJ. P. (1969) Le rythme cardiaque chez Locusta migratork. Bull. Sot. 2001. FT. 94, 677-695. SOANSA. B. and SOANSJ. S. (1968) Observations on the rate of heart beat in the various stages of the tiger beetle, Ct&dello cancel&a Dej. Cum. 5%. Indin 37, 108. TENNEYS. M. (1953) Observations on the physiology of the lepidopteran heart with special reference to revetsal of the beat. Physiol. Camp. Oecol. 3,286-306.