H.C.Lim. M.Sc

Suggested short titIe:

Cytologicul studies of Teleogryllus species.

H.C.Lim. M.Sc. Entomology

Cytological studies of Teleogryllus species and their hybrids (Orthoptera:Gryllidae). By Hai-Choo Lim

Abstract

Testes from nymphs of the last three instars of ton populations of Australasian black field crickots, Teleogryllus commodus and T. oceanicus, and their hybrids were examined to determine the number and morphology of their chromosomes~ AlI strains gave counts of 27 in the male. The karyotypes of different strains and the hybrids are described in detail with illustrations and idiograms. Sorne anomalies in chromosomo number and structure were found, particularly in the intraspecific hybrids, notably in the occurrence ~f polyploid cells in the hybrids of !. commodus and in the interspecific hybrids. Polyploid cells also occurred occasionally within some strains of both species. This i8 the first report of polyploidy in Grylloidea.

Chromosomal polymorphism was common. Lampbrush chromosomes were round in Metaphase l of interspecific hybrids and in the intraspecific hybrids of !. oceanicus. This is probably the first report of lampbrush chromosomes in Metaphase l in the Orthoptera.

Variation in Karyotype indicate that speciation may be occurring in T. commodus. CYTOLOGICAL STUDIES OF TELEOGRYLLUS SPECIES AND THEIR HYBRIDS (ORTHOPTERA:GRYLLIDAE)

BY HAI-CHOO LIM

, A THESIS

Submitted ta the Faculty of Graduate Studies and Research in partial fulfilment of the requirements for the degree of Master of Science

McGill University April, 1968

\ 1 \ .0 Hai-Choo Lim 1969 / AC KNOWLEDGEMENTS

The author wishes to extend her sincere appreciation to Dr.

D.K.McE. Kevan and Dr. V.R. Viclœry, under whose. direction this work has been oarried out, for their guidance, encouragement and helpful criticism throughout the course of this study. l would also like to acknowledge Dr. W.F. Grant for his "advice on technique and for giving ungrudgingly of his tirne on numerous occasions.

The author would also like to express hor thanks to the mernbers of the staff and graduate students of the Department of Entomology at

Macdonald College for their interest and critioism. Thanks are also due to the laboratory technioians Mrs. E. Symthe and Miss D. Johnstone for their kind assistanoe.

Financial assistance from the National Researoh Council of Canada is gratefully acknowledged. TABLE OF CONTENTS

I. INTRODUCTION ...... " ...... 1

II. LITERATURE REVIEW' •••••••••••••••••••••••••••••••••••••••••••• 3

III. MATERIALS AND METHODS • •••••••••••••••••••••••••••••••••••••• 8 A. Materia1s ...... 8 B. Methods ...... 10 1. Dissection of gonad ...... 10 2. Fixative and staining • ••••••• $ •••••••••••••••••••••• 10 3. Method of ana1ysis ...... 11

IV. RESULTS ...... 13

A. Chromosome number • ••••••••••••••••••••••••• e • 0 •••••••••• 13 B. Chromosome structure ...... 14 C. Sex-determination ·...... 15 D. Description of karyotypes ·...... 16 1. Te1eogry11us oommodus ·...... 16 2. T. commodus Hybrids ••••••••••••••••••••••••••••••••• 19 3. Te1eogryllus oceanicus ...... 21 4. T. oceanicus Hybrids • ••••••• 0 ••••••••••••••••••••••• 23 5. Interapecific Hybrid • ••••••••••••••••••••••••••••••• 24

V. DISCUSSION ...... 26

VI. CONCLUSION ...... 36

VII. S~Y •••••••••••••••••••••••••••••• 0 ••••• ·••••••••••••••••• 38

VIII. REF'1'RENCES •••••••••••••••• e •••••••••• e: ••••••••••••••••••••• 40

IX. TABLES AND FIGURgS 1.

I. INTRODUCTION

Cytologists have long s~nce found that insects provide a very fel~ile field for investigation. In addition to the Diptera, Hemiptera and Coleoptera, the Orthoptera is a favoured order for cytologioal study.

Numerous species of the Superfamilies, Tetrigoidea and Aoridoidea, have been studied by many workers. The Superfrumily,Tettigonio~dea, has also been investigated by some workers, but less thoroughly. Among the

Ortho~tera, least attention has been paid to the Grylloidea. Sorne workers

(Ohmaohi, 1929; Randell.and Kevan, 1962) have encoUDtered considerable difficulty in preserving chromosomes of thè Gryllidae in good condition, and it is partly for this reason that the group has been neglected. No comprehensive study has been carried out on this group.

Recent cytological investigati9ns in the fieJd of insect taxonomy have dealt with five main are as of study:

1. Karyotypes of mitotic ohromosomes.

2. Meiotio chromosomes, including spermatogenesis and the mature sperme

3. Salivary gland chromosomes (almost entirely limited to the larval

stages of Diptera).

4. Heterochromatio regions of chromosomes and variations in DNA content. 5. Other variables, Buch as postreduotional meiotic ohromosomes, diffuse

centromeres, sex-determination and male haploidy.

Karyotypic analysis has played an important part in the solution of taxonomie problems in Many plant and animal groups. The present work has involved a study of the ohromosome complements of Australian black 2. field crickets of the genus Te1eogry11us Chopard. Interest has been fooused on the chromosome number and the morpho1ogy of ohromosomes in the germ ce11s, with special reference to the re1ationship botween cyto1ogica1 data and taxonomy. Ife II. LITERATURE REVIEVf

The oommon blaok field crickets of Australia and New Zealand, which are naw plaoed in the genus Teleogryllus Chopard,196l, have long

been confused under a single specifie nama, oommodus, combined with various generic names (Acheta, Gryllus, Gryllulus, Teleogryllus). Leroy (1964) and Chen, Vickeryand Kevan (1967), however, have shawn by means

of morpgological and other characters that two different species, Teleo gryllus commodus (Walker,1869) and !. ooeanicus (Le GUillou,184l), are involved; the former species being more southerly, and the latter more

northerly in distribution. The name servillei Saussure,1877, which has

also been used for the black field cricket of Australia, and which re-

placed the preoccupied name, f~liginosus Serville,1838, is now regarded

as a synonyrn of commodu~, although possibly meriting subspecific status

(Bigelaw and Cochaux, 1962; Chen, Vickery and Kevan, 1967). Ohmachi and

Matsuura (1951), who studied the morphological and physiological characters of Japanese field criokets naw placed in the genus Teleogryllus also found that more than one species had been oonfused under a single name, mitratus Burmeister,1838.

Teleogryllus commodus has been recorded by Chopard (1961) from widely distributed localities in Australia. Hogan (1966) also indicates that it has a wide distribution over the Australia continent, but that it is not present in central Australia. The species also occurs in New

Zealand.

II< In referring to species cited by other authors, the names used hare have been revised, rnostly in accordance with Randell (1964). 4.

Aooording to Chopard (1951), who olassified the Austra1ian black field oriokets in the genus Gryllu1us, oceanicus is not common in Australia but very widespread in Ooeania. He regarded it as an insular raoe of

OOIDnlodus. Both were transferred by Chopard (1961), on morpho1ogica1 grounds, to his new genus, Teleogryllus,.

No marked difference in morpho1ogy between field crickets from

Quoens1and and those from southorn Australia were found by Hogan (1965), but a genetio difference has been shown by other workers. Bige10w (1962) and Bigelow and Coohaux (1962) found that the crossing of FI progeny of southern (Victoria and South Austra1ia) strains produced large numbers of healthy F2 nymphs, but that orossing a Queensland strain with either the Victoria or South Australia strains'produoed only sterile FI offspring.

Chen, Viokery and Kevan (1967) in their morphological comparison of

Teleogryllus populations, showed that the Queensland strain:was ~orpho logical1y different from others studied by them and that its was simi1ar to the Hawaiian species, Te1eogryl1us oceanicus (Le Gui1lou). Hence, the Queensland strain must bel regarded as a distinct species from the southern strains. It should be noted, however, that there is evidence that both T. oommodus and T. ooeanicus ooour in S.E. Queensland (Chen,

Vickery and Kevan, 1967).

Re1ative1y 1itt1e work has been carried out on the oyto1ogy of crickets, the main oontributions being those of Baumgartner (1904,1929),

Brune1li (1909)*, Honda (1926), Ohmaohi (1927,1929,1932a,1935), Tateishi

(1932)''', Piza (1945,1946), Randell and Kevan (1962), and Manna and

Bhattacharjee (1962,1963,1964). A range of chromosome numbers in the

* Not consu1ted in original -- cited by Makino (1951) Gry110idea from 2nt=9 in Eneoptera aurinamensis (De Geer) (Piza, 1946) to 2nt=29 in several speoies of Gry11us (Baumgartner, 1904; Ohmaohi, * . 1929,1935; Tateishi, 1932 ; Piza, 1945; Rande11 and Kevan, 1962).

The number of spermatogonia1 ohromosomes in Te1eogry11us mitratus

(Burmeister) has been reported to be 27 by sorne authors (Honda, 1926;

II< Ohmaohi, 1927; Tateishi, 1932). Honda and Iriki (1932) a1so worked on this speoies and found that the chromosome number was 25 in individua1s from Manchuria, China, and 27 in those from Kyoto, Japan. In the former there was a V-shaped X chromosome, tvlenty-two rods and two other V-shaped chromosomes which were not found in the latter population. These two extra V-shaped chromosomes oou1d be oonsidered as multiple ohromosomes.

Multiple ohromosomes have been reported in the genus Loxob1emm~ (Gry11inae) with a ohromosome number of 13-15 being recorded by Honda

(1926), but 11-13 by Ohmaohi (1932b).

Both Gry11us assimi1is F.(sensu 1ato) and G. oampestris L. have the same chromosome number 2n~=29 (Baumgartner, 1904; Ohmaohi, 1929,1935;

Piza, 1945; Rande11 and Kevan, 1962). Ohmaohi states that the chromosomes are all short roda or spheres, with a V-shaped sex chromosome muoh larger than the autosomes and that "this is the highest chromosome number evor known in Grylloidea".

Acheta domestioua (L.) was studied by Baumgartner (1904), and

Meeka (1913) * , who observed simi1ar chromosome numbers: 21 in the male and 22 in the fema1e. Both authors recorded n e ll (t) in both Metaphase land Metaphaàe II.

II< Not consulted in orie.:inal -- cited by Makino (1951) 6.

Randell and Kevan (1962) worked on Gryllus pennsylvanicus

(Burmeister), G. fultoni (Alexander), ~. veletis (Alexander and Bigelow), and G. rubens (Scudder), and noted that the chromosome number at spermato gonial metaphase was very constant, with a count of 29 in aIl species.

The lowest chromosome number recorded for the subfamily Gryllinae is~';).l, reported fol' Modicogryllus minor (Shiraki) by Ohmachi (1929,1935).

The sex-mechanism in Gl'yl1oidea appears normal1y to be of the xot

XX~ type and the shape and the size of the sex chromosomes are remarkably oonstant (Honda, 1926; Ohmachi, 1927,1929), at least within the family

Gry11idae,s.str. Only a feVl exceptions are known and these are in species belonging to other families: for instance, in Oecanthus longicaudus

(Matsumura) (Oecanthidae), an XY-XX mechanism has been noted by Ohmachi

(1927). Multiple sex-mechanism was a1so found by Piza (1946) in Eneoptera surinamensis (De Geer) (Eneopteridae) in which there is an extra Y chromo some in the male (XY Y and XX). The X and YI are large metacentric 1 2 ohromosomes and the Y2 is rod shaped; the chromosome number is 9 in the male and 8 in the female of this species.

Randell and Kevan (1962) studied the hybridization of oertain

American field crickets. Crosses between Gryllus rubens and G. assimi1is showed no abnormalities in chromosome behaviour either at mitosis or at meiosis in FI and F2 offspring. Hybrids obtained between~. assimilis and "Texas half-triller" (a species not yet formally named), and between

~o pennsylvanicus and G. assimilis, both showed a wide variety in the number of chromosomes in Metaphase II; thi:;; may have been caused by the failure of synapsis. A double bridge was formed in Anaphase l of hybrids 7. between G. fultoni and G. veletis and the authors suggested that pairing had been inoomplete i~ the hybrid~ The phenomena of failure of synapsis and inoomplete pairing in.hybrids mny give rise to ohromosomal and genio sterility.

From studi~s of the ohromosomes of interspeoifio hybrids between

Teleogryllus (then Gryllulus) speoies, Ohmaohi, Fukuda and Kamizima (1953) found that the male diploid ohr'omosome number at the spermatogonial metaphase of T. ~ (Ohmaohi and Matsumura) was 27, vdth aIl the autosomes rod-shaped in appearance. In!. yezoemma (Ohmaohi and Matsumura), 2n was

25 for male, with a pair of V-shaped autosomes. In the hybrida obtained bet~een !. ~ females and !. yezoemma males, 2n for the male was 27 in

FI individuals, but the reciprocal hybrids between T. yezoemma females and T. ~males showed three different ohromosome numbersin FI and F2 males. These were: ffrst, 2n=27 (most of the offspring had this number); second, 2n=26 with one V-shaped chromosome: and third, 2n=25 with a pair of V-shaped chromosomes.

Manna and Bhattacharjee (1962,1963,1964) studied chromosomal polymorphism in Gry1lidae. From their observation of 417 males of

Pteronemobius taprobanensis (Walker) (Nemobiinae), they found that 309 individuals were heterozygous; 162 of those were heterozygous for chromo some 4, 69 for chromosome 6 and 78 for both chromosome 4 and 6. At

Metaphase l, heterozygous chromosomes appeared as hook-shaped struotures formed from a J-shaped and a rod-shaped chromosome D The separation of hetero",orphic chromosomes in anaphase was norme.l and no disturbance in the meiotic process was observed either in hGterozygous or in homozygous individuals. 8.

III. MATERIALS AND METHODS

· A. Materials

Specimens from ten strains of ,Teleogryllus crickets, belonging

to two species-- !o commodus (Walker) and!. oceanicu~ (Le Guillou) -- and originating in different geographical areas of Australia and New

Zealand, and from the Society Islands, were studied, together with their

hybrids. The strains had been in culture at Macdonald College of McGill

University for several generations. The strains, hybrids, sex and origins

of the material studied are shown in the following table:

Species Strain* Sex Origins (Fig. 1)

Teleogryllus Qa t+~ Adelaide, South Australia. commodus Qc 1; Burnley, Viotoria. Qd 1> Adelaide, South Australia. Qk t Kaikoura, South Island, New Zealand. Qt t Hobart, Tasmania. Qw ét-+!f- Perth, Western Australia o Qz ét-t!f Auckland, North Island, New Zealand. Hybrids QWc t Qwq. X Qca' Qwk ~ Qwq. X Qkt Qza t- Qz.!f X Qaô

Teleogryllus Qayr 6" ~~- Ayr, Queensland. oceanicus Qh t' Tahiti, Society Islands. Qn t' Inghrum, Queensland. Hybrids Qayrh t' QayrEl- X Qh~ Qhayr () Qh,!f- X Qayr

T. commodus X Qth t' Qt!f- X Qh

* The symbols used are consistent with those previously employed by Bigelow (1962), BigeloVl and Cochaux (1962) and Chen, Vickery and Kevan (1967), except that further strains have been included, necessitating additional symbols. The sources of strains not referred to by Chen et al. (1967) were as foll~ls: Qd from Dr. T.O. Browning, Adelaide; Qt,~ayr and Qh from Dr. T.W. Hogan, Burnley, Victoria; Dr. Hogan apparently obtained the last strain from Prof. G. Cousin or Dr. Yu Leroy, Paris. 9.

The tissues used for examination were testis and ovary. Attempts were made to use the nervous system, salivary glands and malpighian tubules, but they were unsucoessful. Mitotic division was either absent

or very rare in the testicular follicles and completely absent in the ovary of adult inidividuals, sa that it was necessary to use only the

immature stages (Randell and Kevan, 1962). The last three nymphal in

stars were examined. The instars were distinguished by means of their wing buds (Randell and Kevan. 1962). In the earliest instar used, the wing buds are visible although very small and not easy to see in the antepenultimate instar (they are not visible externally before this stage).

In the penultimate instar, the wing buds are still small and narrow, the posterior pair reaching only' to the middle of the second abdominal tergum.

In the last nymphal instar the wing buds are large and broader with the apices of the metathoracic pair reaching the middle of the third abdominal segment. The sex of the nymphs can be distinguished from the structure at the posterior end of the abdomen. The males were distinguishable from the females by the absence of any traces of needle-like ovipositor which is clearly differentiated even in the earliest instar studied.

During the investigation, male and female gonads were both examined.

It was, however, very difficult to obtain good and weIl spread metaphase plates from female gonads because cells in the metaphase stage were rare and because no meiotic division oocurs in immature avaries. The materials used for karyotype analysis were thus aIl spermatogonial metaphase cells.

The oogonial metaphase was .used merely to check the expected ohromosome number of the female. 10.

B. Methods

1. Dissection of gonad

The immature insect was put in a plastic tube plugged with cotton

saturated with ether. After a few minutes, the insect became quiescent

and was put on a dissecting tray, dorsal surface uppermost~ Fine-pointed

scissors were used to eut along the mid-dorsal line from behind the head to the anus and the specimen was then pinned fIat on the dissecting tray.

The rather large whi~e testes ware then apparent in the dorsolateral region

of the abdomen. In the famale, the ovaries were oval in shape, covered with the fat tissue and occupying the same relative position as the testes.

The testes or ovaries were removed caref~.llly with fine forceps and washed

in Ringer's solution (Darlington and La Cour, 1962, p.147), and then fixed.

2. Fixative and staining

Some common cytological fixative fluids were tried during the

developmant of the technique, but Most of these were not adopted because they were unsatisficatory or difficult to prepare. Farmer's fluid and

Carnoy's fluid (Smith, 1947) were used in the fixation of aIl material

used for general observation and counting.

A variety of slide-making techniques were tested. A major pro blem with paraffin sectioning methods was that it was difficult to obtain

exact chromosome numbers because one or more chromosomes might be lost or

added during the process. Preparation of par affin sections also was too time-consuming whon compared with the squash method. Another reason for

using the squash technique was that, in karyotype analysis, the data are

obtained frolll the measurement of chromosome sets in which a11 the chromosome ll. complements must be exposed in one plane with their entire length visible.

This is possible only by means of the squash method. AlI photographs and drawings were made from squash preparations. The preparation of stains and the staining sohedule are from Smith (1947), Darlington and

La Cour (1962, p.144 and 159), Snow (1963), and MacDonald and Harper

(1965). Among the different. methods tried, the alcoholic hydrochloric .: acid~carmine staining method gave the best results. Although the rapid

Feulgen squash method gave a means of quick preparation, the slide pro duced in this way became useless' after two or three days without permanent preparation.

Sometimes, the slides were made permanent, using a dry-ice freez- ing technique (Darlington and La Cour, 1962, p.164) and Euparal mounting medium, before examination. However, the making of permanent preparations was often unsuccessful, so that most of the slides examined were, in tact, temporary preparations, with the coverslips ringed with paraffin-vaseline sealing compound after squashing. By this method, preservation for three or four weeks was possible.

3. Method of analysis

AlI chromosome counts were made using weIl spread metaphase preparations observed at a magnification of 1250X. The number of chromosomes was determined by first counting the number in the spermatogonial lnetaphase. The number so obtained was then contirmed by making counts of the haploid number in both the first and second meiotic divisions.

Drawings of chromosome complements were made with the aid of a 12. camera 1ucida. The chromosomes were first out1ined in their actua1

1ength ré1ative to each other, after which a carefu1 study of each chromosome was made, and detai1s fi11edin.

Measurements were made of the 1ength of the ohromosomes, in both the drawings and photographs, by using a side-screw divider and triangular boxwood metric scale (both supplied by The Hughes-Owens Co., Montreal,

Canada.). The total chromosome length (T .CoL.) and arm ratio were then calculated, and idiograms made of the karyotype of each strain, according to the data obtained. In the idiograms, the chromosomes were arranged in order of descending length of the short arma

Chromosomes can be differentiated into groups according to the position of the centromere. Their classification on this basis has' beon attempted by Levan, Fredga and Sandberg (1964) whose recommended nomenclature of chromosomes is as follows:

Centromeric Position Arm Ratio Chromosome Designation

Median sensu stricto 1.0 M Median region m (metacentric) 1 0 7 Submedian 3.0 sm (submetacentric) Subterminal st (subtelocentric) 7 0 0 Terminal region t (acrocentric) Terminal sensu stricto 00 T (telocentric)

The present author, however, disagreeswith the limits of arm ratio of the first three groups. From the analysis of more than one hundred karyotypes li the following limits for the arm ratios were re- calculated. Tho chromosomes fall into four groups as follows:

metacentric 1.0-1.3 submetacentrio 1.3-1.7 subte locentric 1,.7-7.0 acrocentric 7.0- 00 13.

IV. RESULTS

Cytologioal preparations showed that mitotic division was commonest in the antepenu1timate nymphal instar, whi1e meiotic division was commonest in the last nymphal instar. The testicular follic1es of the peneu1timate nymphal instar contained cells in both meiotic and mitotic division.

A. Chromosome number

The resu1ts of observations are as listed below (mm;::mitotic metaphase; MI=meiotio metaphase 1; MII=meiotic metaphaseII):

Species Strain mm MI MIl Remarks

Te1eogrlllus Qa 276- 14 13,14 Polyploid cells in mm oommodus 28~ Qc 27 <3' 14 13,14 Qd 278- 14 13,14 6x polyploid cella in MI Qk 27g- 14 13,14 Qt 27 (J' 14 13,14 Qw 27 g. 14 13,14 281- Qz 278' 14 13,14 28.!} Hybrids Qwc 27'it 14** 13,14 Po1yp1oid ce11s in mm Qwk 27~ 14 ? Chromosomes strong1y confused with threads Qza 27t1' 14 13,14

Te1eo~ryllus Qayr 27~ 14 13,14 oceanicus 28~ Qh 27"3' 14 13,14 Qn 27 ëJ' 14 13,14 Po1yploid cells in mm Hybrids Qayrh 27 Cf' 14 13,14 Qhayr 27 é1' 14 13,14 Lampbrush chromosome in· MI T. commodus X Qth 25-28Ô' 14-16 variable Po1yploid cells in mm, super T'. oceanicue numerary chromosomes, single bridge in MI and MIl, 1amp brush chromosome in.MI

Ijt expected ** from Prophase l

AlI strains gave counts of 27 in the male and 28 in the fama1e. 14.

The ohromosome number was very stable throughout both speoies, even in the hybrids, except for the interspecific hybrid Qth.

B. Chromosome structure

Although the size range of ohromosomes among different pairs was small and it was difficult to distinguish between them, the X chromosome was very easy to distinguish from the autosomes due to its large size and to the fact that it' is unpaired in the male. During the spermatogonial division, the X chromosome was the largest, V-shaped but weak-staining; it never became full.y condensed like the autosomes (Fig. 16) and was always peripheral in position. In the remale, the difference in staining between the X chromosomes and the autosomes was 1ess obvious than in the male, but the two cou1d be distinguished by their size and shape (Fig. 17).

In meiotic prophase, the X chromosome of the male showed positive hetero pycnosis, being condensed and dark-staining, whi1e the autosomes were diffuse; it always maintained a V-shaped appearance at this stage, a1- though the armswere more flexible. There was no difference in staining between the X chromosome and the autosomes in Metaphase 1. At this stage, the X chromosome remained V-shaped without any chiasma formation; it was a1ways situated near one pole and moved towards that pole without previous

.heterotypic division. The X chromosome manifested a relative independence during interkinesis, i.e., it formed a separate vesic1e apart from the dividing nucleus (Fig. 18). In Metaphase II the X ohromosome took a periphera1 or central position, where it was quite difficu1t to distin guish from the autosomes.

1~ny of the autosomes appeared to be rod-shaped without evident 15. centromeres, having chiasmata that were terminal in Metaphase I.

Variation occurred in the length of the diffcrent chromosome pairs, which ranged in appearance from rounded dots to rods and V-shaped bodies several times longer than wide.

The variou6 pairs of autosomes were in"l;erconnected by fine threads, which were also connected to the X chromosome. The threads may perhaps be considered to be a DNA struoture, for, wh en using Feulgen staining, they appeared to clear more than when using other staining techniques. Feulgen staining ia one of the special techniques for the obser"vation of chemical substances of chromosomes. The threads may be of a simi1ar structure to the fine strands of the lampbrush chromosomes

(Figo 19). c. Sex-determination

The mechanism of sex-determination in Teleogryllus is of the protenor type, i.e., xot:XX~, the famala having a pair of homologous X chromosomes and the male onlya single X chromosome (Fig. 70). The 28 chromosomes of the femàle include 26 autosomes and two X chromosomes, the formula for which 18 AAXX. The male has 27 chromosomes which include

26 autosomes and a single X chromosome, for which the formula is AAXO.

During chromosomal reduction, aIl the ova receive 13 autosomes and one X chromosome. In spermatogenesis, the single X ohromosome passes to one pole at the reduction division, so that, two types of sperm are formed.

Half of them have the normal complElment of autosomes and an X chromosome; the other half have only autosomes w1thout an X chromosome (Fig. 20).

Fertilization is randomj zygotes with 26A+XX=28 chromosomes give rise to females; those with 26A+XO=27 chromosomes become males (Fig. 71). 16.

D. Description of karyotypes

1. Teleogryl.lus commodus

(a) Strain Qa, frOID Adelaide, South Australia.

The karyotype of this strain consisted of seven pairs of acro centria (I.II,III,IV,V,VII ffild VIII); two of subtelocentric (VI and IX); two of submetacentric (X and XII); and three of metacentric (XI,XIII and

~) chromosomes. The T.C.L. (total chromosome length) averaged 115.94M, ranging from 106.96 to 124.80M. In the 82 observed cells, 58 were hetero zygous for pair IX (a frequency of about 70.8%, as against 29.2% for the normal homozygous cells). Polyploid cells occurred oacasionally (Fig. 21).

(Seo 'tables 1,2, Figs. 2,22).

(b) Strain Qa, from Burnley, Victoria.

The karyotype of this strain was aharacterized by the presence of only three pairs of subtelocentric chromosomes (!V.XII and XIII) and a metacentric X chromosome, the remaining ten pairs aIl being acrocentric.

No V-shaped or J-shaped autosomes occurred. The mean T.C.L. was lI3.63M, ranging from 102.64 to 117.04~ Polymorphie chromosomes were not of

_~mmon occurrence, but an achromatic gap (understained segment of bi valent) appeared in some cells (Fig. 23). (See tables 1,2, Figs. 3,24).

Although this strain originated from the saros areas as the Qa strain, the morphology of chromosomes was found to differ. There were only three acrocentric chromosome pairs (l,II and VIII); the X chromo- 17.

sm~ was metaoontrio; pairs XII and XIII were also metaoentrio, the

latter having a seoondary constriotion on the middle of one armj the

remaining eight pairs inoluding two submetacentrio (III and VII) and six

subtelocentric pairs (IV,V,VI,IX,X and XI). The Mean T.C.L. was l32.09~,

ranging from 114.40 to l42.72~ At Metaphase l, pair XII and pair XIII

in particular in almost 90% of the oases formed ring-shaped struotures

(Fig. 25), and pair XIII sometimes fused with a bivalent to forro an ab normal oonfiguration (Fig. 72). Hexaploid (6)> polyploid) oells occurred

in Metaphase 1. Although the number of bivalents was impossible to

oount, the occurrenoe of three X ohromosomes in the polyploid cells indicated the condition to be hexaploid (Fig. 26). Chromosomul poly

morphism also occurred. (See tables 1,2, Figs. 4,27).

(d) Strain Qk, from Kaikoura, South Island, New Zealand.

The spermatogonial oomplement showed twenty-seven chromosomes.

The X chromosome was the longest metacentric ohromosome in the whole complement. The other thirteen pairs of autosomes could roughly be

- classified as follows: three pairs of acrooentric (IpII and VII); six of subtelooentric (III,IV,VIII-X and XI); three of submetaoentric (V, VI and XII); and one metacentric (XIII). The mean T.C.L. was 108.49#,

ranging from 100.24 to 119.36~. No heterozygous polymorphism appeared

in this strain. The smallest chromosome, pair l, formed smal1 sphere bivalent with a terminal chiasma in Metaphase l (Fig. 28). Pairs XII

and XIII were eitr~r ring-shaped or bridge-shaped in Metaphase l, the

frequency of appearance of the two forms was as follows: 18.

Total oells with a ring and with two with two observed a bridge form ring form bridge form 122 82 10 30 % 67.22 8.19 24.59 (See tables 1,2, Figs. 5,29).

(e) Strain Qt, from Hobart, Tasmania.

This strain had ~he largest ohromosome oomplement. The mean

T.C.L. was 151.06~ ranging from 137.52 to 180.80». The karyotype had only two aorooentrio ohromosome pairs" one of short (r, 2.52M), and one of long length (VIII, 5 .19JJ.). Besides the Xchrornosome, there were three

long metacentl'ic pairs (XI,XII and XIII, total length from 6.20 to 10. 34JJ.) ;

three submetaoentric (III,IV and VII); and five subtelocentrio (II,V,VID IX and X). Pair XII and pair XIII were always ring-shaped in Metaphase

l (Fig. 73). Out of 198 cells examined, 47 (about 23.7%) were hetero zygous. (See tables 1,2, Figs. 6,74).

(f) Strain Qw, from Perth, Western Australia (the approximate type looality of the speoies). Twenty-seven chromosomes were seen at the metaphasestage in spermatogonial cells. The karyotype consisted of a metacentric X chromosome; pairs III and XIII were short and long metacentric, respec- tively; pairs IV and VIII small submetaoentrio; pairs V to VII short

subtelocentrio; pairs IX and X long subtelooentric; the remaining three pairs (l,II and XI) appeared to be acrocentric. Pair XII was hetero- . morphic, composed of a J-shaped and a rod-shaped chromos orne, this was

weIl seen at Metaphase l on acoount of its hook-shaped appearanoe in

side view (Fig. 30). The mean T.C.L. was 115.05A ranging from 110.00 19. to l19.68~ Of the 87 observed cella, only three (3.5%) were homozygous compared with 84 (96.5%) that were heterozygous. In the 84 heterozygous cells, 61.9% of the J-shaped chromosomes of the heterozygous pair segre gated to the pole as the X chromosome, and 38.1% went to the pole without the X chromosome. (See tables 1,2, Figs. 7,31).

(g) Strain·Qz,fl'om Auckland, North Island, New Zealand.

Thirteen pairs of autosomes and a single X chromosome were seen in several immature males at mitotic metaphase, mitotic anaphase, Meta phase l, Anaphase land MetaphaseII stages in spermatogonial cells. The maan T.C.L. was 120.78.0., ranging froIn 112.30 to 144.64». The X chromosome appeared to bemetacentric; pairs IV, VII,X and XII were short to long submetaceDtric; pairs VI, VIII and XI were subtelocentric; pairs I-III and IX were short to long acrocentric; and pairs V and XIII were meta centric •. The. chromosomes of this strain with a few exceptions showed no polymorphism (Fig. 32). Pair XIII appeared either ring-shaped or elongate bridge-shaped in Metaphase I. Observation of 125 ceUs revealed that 54 cells (43.2%) had ring-shaped and 71 (56.8%) had the elongate bridge- shaped chromosome. (See tables 1,2, Figs. 8,33,34).

2. !. commodus Hybrids (a) Qwc hybrid: Perth (Qw) Strain female X Victoria (Qc) Strain male.

The mean T.C.L. was 90.20A, ranging from 85.84 to 93.4014 This was the sma1lest chromosome complement of any of the material studied.

The chromosomes of pair XIII were short metacentric with an arm ratio of 1.03; those of pair XI were short submetacentric; pairs II and VIII were subtelocentric; and remaining nine pairs were acrocentric of 20.

varying length. The X chromosome was metacentrj.c. In Metaphase l, the

member of the smallest pair (1) sometimes separated faster to the poles

than did other autosomes, as if they were supernumerary chromosomes, a1-

though they are not so (Fig. 35). The chromosomes in this hybrid also

showed polymorphisme Double heterozygous chromosome were common, either

pairs XII and VII or pairs XII and III, with a few occurrences .of a

single heterozygous pair. Pair XII was oonsistently heteromorphic; 5~3.3%

of pair VII and 36.1% of pair III appeared heteromorphio (Fig. 36). The

frequency dis'tribution of oells with heteromorphic chromosomeswas as

. follows:

Total célls Heter~morphic Heteromorphic Heteromorphic Heteromorphic observed XII XII and VII XII and III III and VII

94 6 63 34 1 % 6.38 56.38 36.17 1.07 It is interesting to note that polyploid cells occurred quite

commonly in this hybride The ohromosome number of polyploid cells was

108 (i.e., 8x or octoploid) (Fig. 37). In F2 individuals, polyploid oel1s also ocourred in the peritoneal sheath (Fig. 38) and fat tissues

(Fig. 39). (See tabl~s 1,2, Figs. 9,40).

(b) Qwk hybrid: Perth (Qw) Strain femals X Kaikoura (Qk) Strain male.

The karyotype was highly oonfused by the threads connecting the

chromosomes, it was impossible to associate the chromosomes into pairs or

to make reliable counts of the chromosome number. Even in Metaphase l,

the bivalents were always fused together (Fig. 41) and it was very difficult

to study the recombination and segregation of the chromosomes in detail.

Howover, in the diplotene stage and in the diakinesis, normal structurEls 21. were obaerved as in other strains. Fourteen bivalents could be Beon

(Fig. 42).

(a) Qza hybrid: Auckland (Qz) Strain female X Adelaide (Qa) Strain male.

The karyotype consisted of three metaoentria pairs (XII,XIII and

~); six aubmetacen.tria pairs (IV-V and VII-X); and t'ive aarocontria pairs

(I-IlI,VI and XI). No subtelocentria chromosome was present. The mean

T.C.L. was 121.30~, ranging from 113.28 to 128.96~ Pair VII was hetero- m~~rhiG, being an unequal bivalent and oeeul'ring in about 90% of the cells studied. (See tables 1,2, Figs. 10,43,44,,45).

3. Teleogryllus oceanicus

(a) Strain Qayr, fromAyr,Queenslarid. Both mal~ andfemale lndivi

\.,',' ,...... ," somewas metaeentric, with a armrat.:i.o ofle09~ .: The: chromosomes ranged . . " ." ~n length from 95 •. 76tolil.44JAwitha.xIY3a~T.C'.T.J.;~oflll.32~~ .A single heteromorphie pair (VIII) ,. (Fig.46)eo~ol'lly ~~peared in Metaphase l, . . . . . ' . and in a few oases, double heterolllorph:tc:pairsoeeurred(VII and VIII).

. " : From the .observation of 112 eells, 103 were heteromorphiè for pair VIII, and 8 for both pairs VII and VIII. Only one cell was homomorphie.

Thua, the fre~uency of heterozygotes for pair VIII alone was about 91.9%, and for pairs VII and VIII about 7.1%. Aohromatio gaps, present at one end of some bivalents, were aeen in Metaphase l (Fig. 47). (See tables

1,2~,~igso Il,48). 22 •.

(b) Strain Qh, from Tahiti, Society Islands.

Thirteen pairs of autosomes and an X chromosome were seen in males at mitotic metaphase, mitotic anaphase, Metaphase l, Anaphase l,

Metaphase II and Anaphase II. The mean T.C.L. was l28.60~ ranging from

117.04 to·133.20». The X chromosome was of the long metacentric type; pairs I-III,IV-VI,VIII-IX and XI were short to long acrocentric; pairs

VII and X were subtelooentric; pairs XII and XIII appeared as long metacentric chromos omes. Heterozygouschromos.omes were very rare in this strain (Fig. 49). Of 254 cells observed, only 8 showed single hetero zygotes. (See tables 1,2, Figs. 12,50).

(c) Strain Qn, from Ingham, Queensland. Six males were observed. The diploid complement consisted of a single metacentric X chromosome and thirteen pairs of autosomes; two subtelocentric. pairs (VII and XIII) and eleven acrocentric pairs (I-IV,

V-VI, VIII-IX and X-XII), ranging from short to long length. No V-'shaped or J-shaped autosomes were present. The mean T.C.L. was l13.65~, ranging from 100.40 to 130.88». Occasionally, polyploid (tetraploid) cells having

52 autosomes and 2 X ohromosomes occurred at mitotic metaphase (Fig. 51).

This may have been due to the non-segregation of chromosomes. Hetero- zygotes possessed the heteromorphic bivalent of either pair VII or pair

XII (Fig. 52). This could be weIl seen from the side view at Metaphase

I. The frequency distribution of cells with heteromorphic chromosomes (pairs VII and XII) was as followa:

Total cells Heteromorphie Heteromorphic Non observed VII XII heteromorphic 86 18 67 l % 20.9 77.9 1.2 23.

Sorne oe11s had aohromatio gaps which were seen at the two ends

of sorne bivalents (Figo 53). (See tables 1,2~ Figs. 13,54).

4. T. oceanicus Hybrids

(a) Qayrh hybrid: Ayr (Qayr) Strain fama1e X Tahiti (Qh) Strain male.

The karyotype of this hybrid was characterized by the presence

of an unequa1 pair of chromosomes: a V-shaped pairing with a rod-shaped

chromosome. Theother autosomes consistod of a sma11 submetacentric

pUir(XIII); two short subtelocentric pairs (II and IV), one long sub

telocentric (X); the remaining nine pairs were acrocentric, ranging

'from 1.99 to 4.16.u in 1ength. The X ohromosome was metacentric with a

secondary constriction at one end. The mean T.C.L. WB.S 102a32.Lt, ranging

fr-om 95.04 to l06.80P. Triple heterozygotes were not unoornmon and thore

were a few double heterozygotes, but no single heterozygotes(Fig. 55).

In the Metaphase l, three kinds of achromatic gaps appeared (Fig. 56).

(See tables 1,2, Figs. 14,57).

(b) Qhayr hybrid: Tahiti (Qh) Strain famale X Ayr (Qayr) Strain male.

The karyotype consisted of four metacentric pairs, including

,'the,X chromosome; six subt€looentric pairs (II-VI and,IX) and four

acrocentricpairs (VIII,X and XII long acrocentrio, l short acrocentric).

The three pairs ofmetacentric autosomes (VII,XI and XIII) all had a

secondary constriction at the end of one arm, they appeared as achromatic gaps of two different types (Figs. 58,59). The bivalents appeared as

1ampbrush chromosomes in Metaphase l (Figs. 58,59). A single hetero

mOl'phic chromosome pair cornmonly occurred (Fig.BO). Thore were a few

occurrences of a double heteromorphic pair and ocoasionally, all the 24.

chromosomes were homozygous. The frequency of heteromorphic chromosomes

was as follmvs:

Total cells Reter omorphic Heteromorphie Non observed IX VII and IX heteromorphic 113 88 17 8 % 77 .87 15.82 6.31 55.5% of the J-shaped chromosome of the heteromorphic pair went

to the pole without the X chromosome# while 44.5% went to the pole con

tainingthaX ch~om~some. 76.1% of pair XIII appeared ring-shaped in Metaphase I. (Seetables'1,2, Figs. 15,61).

5. InterspeOi~ic Hybrid Qth hybrid: !.commodus (Tasmani9.# 'Qt',Strain) female X T. oceanicus

""." (Tahiti, Qh, Strain) male.

Becausa of the variation in,chrOIIH)SOme number. it was difficult

" "-',.: to malœ an idiogram forthis hybr.i'd~,The ohromosome number varied from ,""'.' . 2nt=25-28, ,~epen~i~g:o~':g'~inorioss of' chromos'ornes. In this hybrid,

""": .. ;:,' ', .. '" ,', - ; ..... '.., "cYt,ologfCal,ob~erv'a~fbn' showedsorne abnormalities in ohromosome struoture.

The chromosomes formed' mahy unoonnected univalents in Prophase I. This

could bè seen very olearlyafter the diplotene stage (Fig. 62). In Metaphase l, ohromosomes showed slight lampbrush struoture (Fig. 63)

and there seemed to be one or two supernumerary ohromosomes (Fig. 64).

A single-bridge, or sometimes double-bridge form oocurred in Anaphase l (Fig. 65). In the telophase, some ohromosomes including the super-

numerary chromosomes, remained around the equator region and failed to

join the other chromosomes to form the dividing nuoleus (Fig. 66).

Thus l after the meiotio division, qne or two ohromosomes lay outside the daughter nuoleus (Fig. 67), later to disappear. Sorne spermatids were 25.

two or more times as large as normal (Fig. 68), presumablyas a result o~ unequal segrogation o~ ohromosomes. Oooasionally, polyploid oells ooourred (Fig. 69), but this was not so oommon as in the Qwo hybride 26.

v. DISCUSSION

Chromosomal polymorphism is (luite common in the order Orthoptera.

In Gryllidae, the occurrence of chromos omal polymorphism ia either due to the variable chromosome number in different individuals of a species, or due to the variation of the chromo!3ome structure. The chrOlnosomal polymorphism of Teleogryllus speciesis of the latter type.

The heteromorphic chromosome pairs are unequal and not asymme trical bivalents, as they show a difference in size between the two components. Asymmetrical bivalents shmv a difference in the position of the centromere but no difference in size between the two components.

The origin of unequal bivalents may be due either to sorne interchromo somal rearrangements (probably sorne duplication or deficiency of chromo somal parts of the heteromorphic pairs), or to the unequal pairing of chromosomes. l~na and Bhattacharjee (1964) in their studies on the chromosomal polymorphism in Pteronemobius taprobanensis (Walker) pointed out that the origin of heteromorphic fourth and sixth chromosome pairs may be caused by a duplication in one of the sixthchromosome pair and a deletion in one of the fourth chromosome pair, because the latter comprise two J-shaped and the former tworod-shaped chromosomes in homozygous individuals.

The occurrence of une quaI bivalents has been recorded in many animal groups, especia11y in invertobrates. Short-horned grasshoppers are the best-lrnovm group in which this occurs among insects (Carothers,

1913,1917,1921,1931; Dar1ington, 1936; Vfhite, 1949,195~1954; White and 27.

Nickerson, 1951; Sharman, 1952; Nur, 1961). It has also been reported

for Orthoptera in mole-crickets (Gryllotalpidae) by Payne (1912,1916),

in grouse 10custs (Tetrigidae) by Robertson (1915) and in crickets

(Gryllidae) by Ohmaohi (1935), Ohmaohi and Ueshima (1955) and Manna and

Bhattacharjee (1962,1963,1964). In the Dictyoptera, Vfuite (1941) recorded

it for mantids. Vfuite (1954) pointed out that the unequal bivalent ia

only a special aspect of the general phenomenon of variation in the extent

of the heterochromatic material within the popu1a.tion. He classified the

unequal bivalents into three types according to the mode of' separation

at the first meiotic division. (1) reductional; (2) equational; (3) either reductional or equational. The unequal bivalents of Teleogryllus species

are of the first type.

Chén (1942) has reported that in Arcyptera coreana Shiraki

(Acrididae), a bivalent may be ftunequal Il (S/L) in some and uequal" (L/L)

in other cells of the same individual. This occurs in Teleogryl1us

species.

The occurrence of normal physiological and morphological characters

in heterozygotes indicatas that heteromorphic chromosomes do not have any deleterious effect. They probably possess sorne adaptative signi ficanee. Most types of cytological polymorphism are due to structural rearrangement of chromosome parts having taken place during the evo1ution

of the species. From the eytologieal studies o·f different strains of

Teleogryllus species, it has bean shown that heterom,orphic chromosomes are not common in island strains.

The "fuzzy1t appeurance of orthopteran chromosomes, particular1y 28. during meiotic prophase, has been notcd and described (Hearn a.nd Huskins,

1935; Vfuite, 1940,1954; Ris, 1945; Serra, 1947; Rsu, 1948; Srivastava,

1951,1954,; Gall, 1956; Gall and Ca11an, 1962; Callan, 1957; Hendersoll, \ 1964; Watkins, 1964). This fuzziness, however, is not confined to orthopteran chromosomes, but appea~s to be normal, for instance in amphibian and mannnalian chromosomes. The 1ateral projections that give rise ta the fuzzy appearance have been variously described as haira, or loops, but Ris (1945) claimed that the fuzziness merely re flected a 1atera1 separation of sister chromatid helices. Serra (1947) considered the 'hairs' of such chromosomes ta be rod-like structures of nue le opla.sm 'âep~s,iteci: onthechromonemata. More detailed study showed

"", " that thedi:f.'fuse appearance,hdu~ toth.e presence of fine lateral loops ,";.' :, .. ' :-: .... ; ; ,,," arising from tightlyc,oiled'axJ.al chromosomes (Henderson, 1964).

, . . . ':Sr:tvastava (1951,ï954)'~0;t'~'d: ;tl1a.t 1ampbrush chromosomes appeared at pachy€eIlearidYlerelTlalnt~~n~d~o'the end of di,akinesis, disappearing \; :.~ .: .:. :' ... • . . '. .·f . .... comp1etely atthe,first,metaphase. Hsu (1948) showed that the development of the lampbrushchromosomes in grasshopper spermatocytes proceeds continuously throughoutthe prophase and reaches a maximum at diakinesis.

During prometaphase e. sudden change takes place, the filaments shorten and the outline of the bivalents become gradual1y smoother. "The maximal

1ampbrush activity is shawn at ear1y and mid-diplotene," said Henderson

(1964); '''an unusually e 1aborate 1ampbrush stage condition is found at

1ate dip10tene and diakinesis of male meiosis."

In suitab1e fixed and stained preparations, it was shown that the

1atera1 hair-liIre projections on the 1ampbrush chromosomes of Teleogryllus 29.

species were fine loops of variable extension, and the filaments were

quite straight. Lampbrush chromosomes commonly occurred in prophase,

but the two hybrids, Qth and Qhayr, showed an abnormal condition: the

lampbrush chromosomes not only appeared in prophase and at the end of

diakinesis, but also occurred in Metaphase I. This may be the first

reoord of lampbrush ohromosomes in Metaphase l in orthopteran chromosomes.

Polyploid oells are common in plants, but rare in animaIs, and there are very few reoorded (White, 1934,195],; Mickey, 1945; Rothfels,

1950; John and Henderson, 1862). In some strains of Teleogryllus

species; Qa, Qd of !. commodus and Qn of !. oceanious, polyploid sperma tooytes are occasionally found in the testis, but in the intraspecifio

hybrid Qwo and the interspecific hybrid Qth, especially in the former,

polyploid oells occurred oommonly. The chromosome number of polyploid

cells in hybrid Qwccan be counted. This is the first reoord of poly-

ploidy in Grylloidea.

When polyploid cells were present, they occurred singly, i.e.,

in cysts Which were otherwise composed of diploid cells. These polyploid

cells were probably of no functional significance and there is no evi

dence that they give rise to functional sperms. Sorne polyploid sperma tocytes resulted from a failure to segregate and underwent degeneration during or shortly after the meiotic division. The polyploid cells of

Qa, Qd strains of T. commodus and Qn strain of !. oceanicus may 0.11

belong to this type. other polyploid spermatocytes appear to be physio

logical1y normal and ta pass through the meiosis without any apparent abnormality. In the hybrid, Qwc, for instance, polyploid cells also 30 ..

occurred in FI and F2 individuals. There appears to be no gross morpho logical difference from normal in these hybrids. Even in the non-hybrid strains, Qa, Qd (!. commodus) and Qn (!. oceanicus), no delectable morphological difforence was apparent between normal individuals and those with polyploid cells.

Two types of polyploid cells can be distinguished. The first type arises by failure of anaphase separation at one of the spel~atogonial divisions. Such cells are alwaJiG tetraploiJ., as, for example Il are the polyploid cells of theQn str'ain of T. ~ceanicus (Fig. 51). The second type arises by fusion of two, three, four or more neighbouring cells.

Such cells are pentaploid, hexaploid, heptaploidll octaploid, and 50 on, the pol;yploid cells of Qa, Qd strains ani.:' Q;wc hybrid of !. commodus and of the interspecific hybrid Qth may arise in this way. In the Qd strain of T. commodus, the fusion takes place after the zygotene stage, So that, the X chromosomes are present as univalents and aIl the autosomes as bivalents; no multivalents appear because the chromosomes have already undergone pairing before the establishment of polyploidy (Fig. 26, shows three univalent X chromosome; and numerous bivalents). Multivalents are very rarely observed in Teleogryllus spaoies, but are quite common in polyploids of. other orthopterans. John and Henderson (1962) noted that two types of polyploid cells were found in Schistooerca gregaria (Forsk.): those which contained and those whioh did not contain multivalents. The latter vl8re more o ommon , giving rise to multj.nucleate cl)lls resultin,~ from the failure of oJ~oplasmio divjsion. Rothfels (1950) claimed that both types of. polyploid oells ocourred regularly in aIl species of 31.

"Acridinaeu (presumably the Gomphocerinae on1y).

Outside tho Acridoidea J there are very few well-authenticated records of supernumerary ohromosomes in orthopteroid inseots.They have been studied in mole-crickets (Gryllotalpidae) by Maki:n0, Ni1.yama and Asana (1938); Steopoe (1939); and Asana, Makino and Niiyama (1940).

Out of 49 male Gryllotalpa afrioana (Beauv,) examined, four possessed

one supernumerary chromosome and three had two (Makino, Niiyama. and

Asana, 1938). The number of Bupernumerary chromosomes i8 inconstant in the hybrid between T. commodus and !. oceanious (Qth). It ma.y vary from 0-2 between individuals, and even in different cells of the same individua1. The origin of supernumerary chromosomos is unknown, but

May be due to abnormal segregation of chromosomes. Undoubtedly, the condition is abnorma1 in this hybride

A1though there is no difference in chromosome number between

T. connnodus and !.. oceani.cus, the karyotypes are differen"l:;. Most of the chromos ornes of 'i'. oceanicus are acrocentric, while very few of this form were found in T. commodus except in the Victoria strain (Qc).

Achromatic gaps occurred in Metaphase l in T. oceanicus but not in T. . - commodus, again with the exception of Victoria strain (Qc). On1y single

heterozyeotes were found in!. oommodus J but in T. oceanious, r.ingle, double and triple heterozygotes occurred.

The two AdelaidA strains of !. commodus (Qa and Qd) showed differenoes in chromosome morphology 1 al though they are from approxime.toly the same area. Strain Qd had three acrocentric pairs, ",hile Strain Qa had seven. In Stl'uin Qd, hexaploid cells and two ring-form bivalents 32.

occurred in Metaphase I; pair XIII had a secondary constriction; it was ring-shaped and was sometimes fused with a bivalent. These unusual

struotures were not found in Strain Qa. It should be noted that Strain

Qa had bean reared in the laboratory for a greater period of time(appro ximately 12 more generations) than Strain Qd. Chromosomal ohanges as a result of laboratory procedures lnny account for some of the discrepancies bet~{een the two strains.

Although the South Island, New Zealand (Qk) strain is believod by Chen, Vickery and Kevan (1967) to represent a subspceies of T. commodus, no great difference in the karyotype be"bween this strain and that from North Island of New Zealand (Qz) was found. The only differ ences were that Strain Qk had three, whereas Strain Qz had four acro centric pairs of chromosomes. Sometimss, two ring-forms occurred in

Metaphase l in Strain Qk, but they were never found in Strain Qz.

Strain Qk was similar to the Tasmania strain (Qt) in that both had two ring-form bivalents in Metaphase l, and that their karyotypes consisted of very few acrocentric pairs (three in Qk and two in Qt, which is the smallest number of acrocentrics found in the material studied). Hetero morphic chromosomes were not common in Strain Qt, only 23.7% of Qt cells showed heterozygotes. The similar structure of the karyotype of the three island strains of T. commodus seenl to indicate that the evolution of chromosomes roay be parallel under insular conditions.

The position of the Victoria strain (Qc) of !. commodus appears unornalous. The karyotype of this strain is unlike that of other T. commodus strains and more similar to that of T. oceanicus. When the 33. st ra in is crossed with the latter species, however, the hybrids are infertile. Crosses between Strain Qc and "typical1l T. commodus from

Western Australia (Strain Qw) are fertile, but chromosome studies show the presence of abnormal (polyploid) cells in the hybrids. This strain appears to be diverging from!. commodus,s.str. and may represent a distinct subspecies, for which the name servillei Saussure is presumably appropriate (see Chen, Viokery and Kevan, 1967).

The hybrids obtained between Auokland and Adelaide (Qz and Qa) strains showed no abnormalities in chromosome struoture or behaviour in either mitotio or meiotio division, and this stability was oarried over into the F2 progeny. These strains doubtless belong to the sarna subspeoies.

The hybrids obtained between the Western Australia strain (Qw) and the South Island, New Zealand strain (Qk) showed abnormal chromosome struoture. This was to be anticipated beoause the latter strain differs oonsiderably in morpho10ey from other strains of T. oommodus. Strain

Qk may be regarded as belonging to a distinct subspeoies although at present it is nameless (see Chen, Viokery and Kevan, 1967).

The interspeoific hybrids obtained between 1:. oommodus, Tasmania strain (Qt) and!. ooeanious, Tahiti strain (Qh) showed a series of aberrational structures. These inoluded loss or gain of ohromosomes, abnormal size of spermatids, ooourrenoe of supernumcrary ohromosomes and polyploid oells. FI progeny were aIl sterile as has been found with crosses between other strains of these two speoies (Chen, Viokery and

Kevan, 1967). Thus we have additional evidence that T. oommodus and 34.

T. oceanicus are indeed different species that are reproductive1y iso1ated.

Evolution and divergence in the differenb strains of Te1eogry11us species, it wou Id seern, are large1y related to clirnatic conditions. Hogan

(1960) found that, in Teleogryllus, none of the Queensland eggs, about 40% of the Victoria eggs and nearly aIl of the Adelaide eggs wen-Î:; into dia pause at 2S oC, so that genetical differences exist between field popula tions of these strains. So far as the Queensland population is concerned this is se1f-evident since the species involved is not the sarna as that of the other populations. These differences probably involve different gene frequencies which can be altered rather quickly in response'to climatic changes. Cochau~ (1965) also pointed out that the reproductive isolation of geographica11y divergences resulting from differences in adaptation to c1imatic conditions, which may or may not be re1ated to morpho10gica1 differences.

In his study of the diapause characters of different geographic populations of Te1eogrylluB, Hogan (1966) states: "Vilian an insect species has a wide distribution, with a range of habitats varying considerab1y in climatic or other conditions or both, then racas develop with charac teristics favouring survival in each type of environment. The adaptations of each race are rnain1y physiological, but morphological changes May occur by mutations that are mainly favourable to survival and are net transmitted to other races because of reproductive isolation. These processes may lead to the developmenb of a new species."

The sterility in intra- and inter-specifie hybrids rnay be due 35. either to structural diffarences between the two constituent sets of

chromosomes or to purely genic causes.

From his studies on eighteen speoies of· Grylloidea, Ohmachi

(1927) conoluded: "There are such relations between the numbor and the

size, 'that the larger the number, the smaller each chromosome is." He

showed that the ohromosomes of Teleogryllus mitratus (Burmeister), which were greater in number (2nt=27) included a number of srnall spheros, while in species with fewer ohromosomes (2nt=2l), such as 11 Gryllus1. tokyoensis IV1a.tsumura>/l and Velarifictorus aspersus (V'valker), the ohromo-

somes Viere aIl in the forra of short rods. In Modicogryllus conspersus

(Schaum), the number of chromosomes was reduced to seventeen because

of tllO presence of a pair of V-shaped chromosomes. In Taleogryllus there is no such relationship between the number and the size of the chromosomes. The strain which had the highest number of V-shaped chromosomes and that which possessed the lowest both have the same total chromosome number •

• This species is not listed by Randell (1964) or by Chopard (1967)~ it certainly cannot belong to the genus Gryllus as its chromosome number is too small. It rnay weIl belong to the genus Velarifictorus Randell. 36.

VI. CONCLUSION

Hutton (1881) suggested that Teleogryllus commodus (under the

hamonymous name of Gryllus fuliginosus Audinet-Serville) was introduced

into New Zealand from Australia. Digelow (1964) also pointed out that

the T. commodus in New Zealand is referred to as an introduced speoies,

apparently as having.arrived there during the past 150 years. Differences

in the morphology between the South Island, New Zealand strain, from

~ikoura, and Australian and North Island, New Zealand, populations (Chen,

Vickery and Kevan, 1967) suggested that the Kaikoura strain was a rela tively isolated population of long standing in New Zeal'and whereas the

North Island strain was probably not. The hybrid obtained between the

Western Australia strain (Qw) and the Kaikoura strain (Qk) showed ab

normal chromosome structure, indicating that the latter was genetically

as weIl as geographically isolated from the former. However, cytological

studies on hybrids between the Kaikoura strain and the populations fram

southeastern Australia (whioh also differ from the Weste~n Australia form) have not yet been undertaken, so that the degree of isolation from nearer Australian populations is unknown.

Chen, Viokery and Kevan (1967) on morphological grounds, pointed out that the populations of !. commodus from Western Australia differ from those from southeastern Australia and both New Zealand strains.

The present hybridization studies have shown that: firstly, polyploid oella occurred in the hybrid obtained between Western Australia strain

(Qw) and Viotoria st~ain (Qo); and seoondly, the hybrid of Western

Australia strain (Qw) and South Island, New Zealand strain (Qk) showed 37. abnorrnal chromosome structure. Thus the Western Australia strain

(lttypical tt !. commodus) is clearly different from the other strains, and a comparable degree of divergence has occurrod. The latter may be regarded as members of "similar, but distinct biogeographic entities of commodus" (Chen, Vickeryand Kevan, 1967). The general subspecies group name of !. eommodus servillei may be applied to aIl of these except possibly the strain from Kaikoura, South Island, New Zealand.

The similarity in karyotype, chromosome structure and number between different strains of T. commodus showed them to be sufficiently closely related to each other as to confirm that they aIl have a common origin and are properly regarded as a single species, but that some divergence has occurred. On the other hand the karyotype, but not the chromosome number, of T. oceanicus differs from that of T. commodus so that it is properly regarded as a separate species, closely related to

T. eommodus.

A phylogenetic tree, based on cytologieal, morphological and physiological evidence, is as follows: Qz Qt 38.

VII. SUMMARY

Ten populations of two Australian black field crickets, Teleo-

~ryllus oommodus and T. oceanicus, and thei~ intra- and inter-specifie hybrids were studied. Populations of the former were from Western

Australia, southeastern Australia, Tasmania and New Zealand; those of the latter were from the Society Islands (Tahiti) and Queensland,

Australia.

Karyotypes of '!;he speoies agree in having a ohromosome number of 2n6~27. Idiograms of karyotypes were made. The chromosomes can be divided into four distinct groups: metacentric, submetacentric, subtelocentric and acrocentric, according to the position of ~he centromere.

The occurrence of these four groups in the karyotype showed great variation between different stro.ins and hybrids. Analysis of the chromosome complements showed that acrocentric chromosomes were very common in !. oceanicus but rather rare in !o commodus except in the Victoria strain.

Understained gaps were found only in!. oceanicus and the Victoria strain of T. commodus. Chromosomal polymorphism was common, occurring in the form of single, double and triple heterozygous chromosome pairs.

P'olyploid cells occurred in the intraspecific hybrid of !. commodus betwccn the Western Australia and Victoria strains and in the interspecific hybrid between the Tasmania strain of .!!.~~ and the

Tahiti :Jtrain of T. oceanious. They occasionally appeared in both

Adelaide strains of T. commodus and in the Queensland strain of !.

~icus. The polyploid cells may arise either by failure of anaphase 39.

separation or by fusion of two, three or more neighbouring cells. This

is the first report of polyploidy in the Grylloidea.

Lampbrush ohromosomes occurred in Metaphase l in the intra

speoific hybrids of !. oceanicus and the interspecifio hybride This is an abnormal feature in these hybrids and may be the first report of such chromosomes in Metaphase l for the Orthoptera. Lampbrush ohromosomes appeared commonly in the meiotic prophase of both species.

The variability of chromosome number in interspeoific hybrid may be oaused either by the presence of supernumerary chromosomes, inconstant

in number, or by unequal segregation of chromosomes.

The variation of karyotypes in different strains indicated that speciation may be occurring. Although successful hybridization occurs between the Western Australia strain and other strains of !. commodus, divergence has occurred and speciation is apparently in progress; the latter can be considered as a subspecies (!. ~. servillei), with the exception of the South Island, New Zealand strain which may perhaps be regarded as constituting a third subspecies, althoubh scarcely on cytological evidence.

The position of the Victoria strain of T. coinmodus seems anoma,lous because it was found to be similar in karyotype to!. oceanicus, but produced sterile offspring when crossed with the latter. It produced fertile progeny when crossed with "typical" !. commodus from Western

Australia indicating that it balongs ta !.conunodus but differs in karyotype from othor T. commodus strains. 40.

VIII. REFERENCES

Asana, J.J., S. Makino, and H. Niiyama 1940 A chromosomal survey of some' Indian insects. III. Variations in the chromosome number of Gryllotalpa africana, due to the inolusion of supernumerary ohromosomes. ______a J. Fao. Sei. Hokkaido Univ. (VI), 7: 59-72.

Baumgartner, W.J. 1904 Some new evidenoe for the individuality of the ohromosomes. Biol. Bull. 8: '1-28.

1929 Die spermatogenese bei einer Gryl1e, Nemobius fasoiatus. Z. Zellforsch. 9: 603-639.

Bige1ow, R. S. 1962 Factors affeoting developmental rates and diapause in field crickets. Evolution, ~: 395-406.

1964 Note on the blaok field crioket in New Zealand. New Zeal. Ent. 3: 9.

Bigel~l, R.S. and P.S.A. Cochaux 1962 Intersterility and diapause differences between geographioal populations of Teleogryllus aommodus (Walker) (Orthoptera: Gryllidae). Aust. J. Zool. 10: 360-366.

Callan, H.G. 1957 The lampbrush ohromosomes of Sepia officianlis L., Anilocra physodes L. and Soyllium catulus Cuv. and their struotural relationship to the lampbrush chromosomes of the Amphibia. Publ. Star. Zool. Napo1i, 29: 329-346.

Carothers, E. E. 1913 The Mendelian ratio in relation 'GO certain orthopteran chromosomes. J. Morph. 24: 487-511.

1917 The segregation and recombination of homo1ogous chromosomes as found in two genera of Aorididae (Orthoptera). J. Morph. ~: 445-521.

1921 Genetica1 behavior of heteromorphic homologous chromosomes of Circotettix (Orthoptera). J. Morph. ~: 457-483.

1931 The maturation divisions and segregation of heteromorphic homo1ogous chromosomes in Acrididae (Orthoptera). Biol. Bull. 35: 324-349. 41.

Chen, G.T., V.R. Vickery, and D.K.McE. Kevan 1967 A morpho1ogical comparison. of Antipodean Te1eogry11us species (Orthoptera: Gry11idae). Cano J. Zool. 45: 1215-1224.

Chén, S.T. 1942 Dufferentia1"chromosomes of Aroyptera coreana Shiraki (Orthoptera) • J. Morph. 71: 77-100.

Chopard, L. 1951 A revision of the Australian Gryl1oidea. Rec. S. Aust. Mus. 9: 397-533.

1961 Les division du genre Gry11us basees sur l'atude de l'appareil copulateur (Orth. Gry11idae). Eos, Madcid, ~: 267-288.

1967 Gryl1ides Fami1y Gryl1idae: Subfamily Gryllinae (Trib. Gymmogry1lini, Gryllini, Gry11omorphini, Nemobiini). Orthopterorum Catalogus, 10: 1-211.

Cochaux, P. 1965 Croisements intraspecifiques et specification chez quelques Gry11ides des genres Gry11us et Te1eogry11us (Orthoptera: Gry11idae) • Cano J. Zool. 43: 105-124.

Dar1ington, C.D. 1936 Crossing over and its mechanical relationships in Chorthippus and Stauroderus. J. Genet. 33: 465-500.

Darlington, C.D. and L.F .La Cour 1962 The Handling of Chromosomes (4th Ed.). George Allen and Unwin, London. Gall, J.G. 1956 On the submicroscopic structure of chromosomes. Mutation: Brook-haven Symp. in Biol. 8: 17-32.

Gall, J.G. and H.G. Callan 196~ H3-uridine incorporation in lampbrush chromosomes. Proo. nat. Acad. Sei., Wash. 48: 562-570.

Hearne, E.M. and C.L. Huskins 1935 Chromosome pairing in Me1anoplus femur-rubrum. Cytologia, ~okyo, 6: 123.

Henderson, S.A. 1964 RNA synthesis during male meiosis and spermiogenesis. Chromosoma, Berl. 15: 345-366. 42.

Hogan, T. Vi. 1960 The onset and duration of diapause in eggs of Acheta corrmodus 0Ya1ker) (Orthoptera). Aust. J. Biol. Soi. 13: 14-29.

1965 Some diapause characteristics and interfel'tility of three geographic populations of Teleogryllus commodus 0Valker) (Orthoptcra:Gryllidae). Aust. J. Zool. 13: 455-459.

1966 Physiologioal differences between races of Te1eogryllus commodus (Walker) (Orthoptera:Gryllidae) related to a proposed genetic approach to control. Aust e J. Zool. "-14: 245-251. Honda, H. 1926 The ohromosome number and the multiple chromosomes in Gryllinue. Proc. Imp. Acad. Tokyo, 2: 562-564.

Honda, H~ and S. Iriki . 1932 A short note on the chromosomes of crickets. Sci. Repts. Tokyo Bunrika Daigaku (B), !: 133-135. Hsu, T.C. 1948 The relations between heteropycnous, spiralization and 1ampbrush formation of the chromosomes in the spermatogenesis of the Acrididae. J. Genet. 48: 311-315.

Hutton, F.W. 1881 Insects Orthoptera. In Catalogues of New Zealand Diptera, Orthoptera, Hymenoptëra; with descriptions of the species. Colonial Museum and Geological Survey, New Zealand, Wellington: 71-94. John, B. and S.A. Iwnderson 1962 Asynapsis and polyploidy in Schistocerca paranensis. Chromosoma, Berl. 13: 111-147.

Leroy, Y. 1964 La singalisation acoustique chez les Gryllides. Ann. Biol. 3: 400-428.

Levan, A., K. Fredga, and A.A. Sandberg 1964 Nomenclature for centromeric position on chromosomes. Hereditas, 52: 201-220.

MacDonald, M.D. and A.M. Harper 1965 A rapid Feulgen squash method for aphid chromosomes. Cano J. Genet. Cytol. !: 18-20. 43.

Makino, S. 1951 An Atlas of the Chromosome Numbers in AnimaIs (2nd Ed.). Iowa State College Press~ Iowa.

Makino, S., E. Niiyarna, and J.J. Asana 1938 On the supernumerary chromosomes in the mole-cricket, Gryllotalpa africana de Beauvois from India. (A preliminary note) • Jap. J. Genet~ 14: 272-277.

Manna, G. K. and T.K. Bhattacharjee 1962 On the chromos omal polymo~phism in a gryllid, Gryllulus confirmatus ~(alk.) (Abstract). 2nd. AlI India Congr. Zool. p.9.

1963 Chromos omal polymorphism in a Gryllid Ftoronemobius taprobanensis (Walk.) (Abstract). Proc. 50th Ind. Sei. Congr. Ft. ~: 472-473.

1964 Studies of Gryllid chromosomes. II. Chromosomal polymorphism in Fternemobius taprobanensis (Vialk.), and chromosome morpho logy of Loxoblemmus sp. Cytologia, Tokyo, ~: 196-206.

Mickey, G.R. 1945 Synapsis and behavior of chromosomes in polyploid male germ cells of Romalea microptera Beauv. J. Genet. 30: 15.

Nur, U. 1961 Mitotic behaviour of an une quaI bivalent in the grasshopper Calliptamus palaestinensis Bdhr. Chromosoma, Berl. 12: 272-279.

Ohmachi, F. 1927 Preliminary note on cytological studies on Gryllodea. Proc. Impo Acad. Tokyo, ~: 451-456.

1929 A short note on the chromosomes of Gryl1us campestris L. in comparison with those of Gry1lus mitratus Burm. Proc. Imp. Acad. To1cyo, 5: 357-359.

1932a On the chromosomes of three species of Gryllodea. Proc. Imp. Acad. Japan, ~: 197-199.

1932b On the homology of chromosomes between two species of the genus Loxob1emmus. Proc. Imp. Acad. Japan, ~: 202-204.

1935 A comparative study of chromosome complements in the Gry1lodea in relation to taxonomy. Bull. Mie Coll. Agric. For. 5: 1~51. 44.

Ohmaohi, F., l. F'ukuda, and N. Kami z ima 1953 Chromosomes in interspecific hybrids between Gryllus emma and ~. yezoemma. Jap. J. Genet. 28: 180.

Ohmaohi, F. and S. :Masaki 1964 lnterspeoific orossing and development of hybrids between the Japanese spcoies of Te1eogryllus (Orthoptera:Gry11idae). Evolution, ~: 405-416.

Ohmaohi, F. and l. Matsuura 1951 On the Japanese large field oricket and its allied speoies. Bull. Fao. Agric. Mie Univ. 2: 63-72.

Ohmachi, F. and N. Ueshima 1955 On the ohromosome oomplements of three nearly related speoies of Loxoblemmus arietu1us Saussure. Bull. Fao. Agrio. Mie Univ. 15: 1-13.

Payne, F. 1912 The ohromosomes of ~ry11otalpa borealis Burm. Arch. Zellforsch. 9: 141-146.

1916 A study of the germ calls of Gry110talpa borealis and Gryllota1pa vu1gariu J. Morph. 28: 287-327. Piza, S. de Toledo 1945 Compotamento do heterocromoElsAmio em nle;uns Ort6pteros do Bras il. Ann. Esc. Agric. Queiroz, Ë..I 1 73·

Ris, H. 1945 The structure of moiotie chromosomes in grasshoppor and its bearing on the nature of "chromomeres" and "lampbrush chr ornas orne s" • Biol. Bull. 89: 242-257. 45.

Robertson. W.R.B. 1915 Chromosome studios III. Inequa1ities and deficiencios in homo1ogous chromosomes: their bearing upon synapsis and the 10S8 of unit characters. Jo Morph. 26: 109-141.

Rothfe10, K.R. 1950 Chromosome complement. po1yp1oidy and supernumeraries in Neopodismopsis abdominalis (Acrididae). J. Morph. 87: 287-315.

Serra, J.A. 1947 Composition of chromonemata and matrix and the raIe of nuc1eoproteins in mitosis. Co1d Spr. Rarb. Symp. Quant. Biol. 12: 192.

Sharman, G.B. 1952 The cytology of Tasmanian short-horned grasshoppres (Orthoptera:Acridoidea). Pap.'Roy. Soc. Tasm. ~: 107-122.

Smith, L. 1947 The acetocarmine smoar technique. Stain Technol. 22: 17-31.

Snow, R. 1963 Alcoholic hydrochloric acid-carmine as a stain for ohromosomes in squash preparations. Stain Teohnol. 38: 9-13.

Sr ivastava , M.D.L. 1951 'Lampbrush' fibres in the chromosomes of Chrotogonus incertus Bolivar. Nature, Land. 167: 7.75- 776.

1954 Studios on the structure of the chromosomes of Chrotogonus incertus Bolivar (Acrididae). J. Genet. 52: 480-493.

Steopoe, I. 1939 Nouvelles recherches sur la spermatogénèse chez Gryllotalpa vulgeris de Roumanie. Arch. Zool. exp. Aoad~ Japan, 8: 445-464.

Watkins, M. J. 1964 Evidence for a. lampbrush type structure in grasshopper spermatocJ~e chromosomes. Exp. Cell Res. 36: 14-18. 46.

White, M. J. D. 1934 Tetraploid spermatocytes in a locust, Schistocerca gregaria~ Cytologia, Tokyo, ~: 135-139.

1940 The heteropycnosis of sex chromosomes and its interpretation in terms of spiral structure. J. Genet. 40: 67-82.

1941 The evolution of the sex chromosomes. l. The XO and XIX2 Y mechanism in praying mantids. J. Genet. 42: 143-172.

1949 A cytological survey of wi1d populations of Trimerotropis and Circotettix (Orthoptera:Acrididae). l. The chromosomes of twelve species. Genetics, 34: 537-563.

1951a Structural heteroz~'gosity in natural populations of the grasshopper Trimerotropis sparsa. Evolution, ~: 376-394.

1951b Cytogenetics of orthopteroid insects. Advanc. in Genet. 4: 267-330.

1954 Animal C~~ology and Evolution (2nd Rev. Ed.). Cambridge Univ. Press, London.

White, M. J.D •. and N.R. Nickerson 1951 Structural heterozygosity in a very rare species of grass hopper. Amer. Naturalist, 85: 239-246.

The references marked with ' >II , in text are cited in Makino (1951). As the;')' have not been consulted in the original J they are not 1isted above. IX. TABLES AND FIGURES Table 1. Karyotypes of Teleogryl1us species (AlI the data measured from mitotic metaphe.se).

01assi- Arm ratio (L/S) fication l II III DT V VI VII VIII IX X XI XII XIII 'X Teleo- grlllus commodus Qa 1.77 - 1.80 1.19 1.16 1.55 1.19 1.36 Qc 2.02 - 3.26 2.85 1.12 Qd 1.63 2.21 1.90 1.78 1.53 - 2.70 2.25 2.06 1.28 1.08 1.08 Qk 1.74 1.94 1.65 1.55 - 1.95 2.55 2.38 2.48 1.39 1.25 1.21 Qt - 2.17 1.44 1.70 1.80 1.75 1.43 - 1.79 2.84 1.27 1.16 1.24 1.17 Qw 1.26 1.36 2.06 1.99 1.98 1.45 3.22 2.18 - 1.11 1.24 Qz 1.41 1.28 2.13 1.34 1.71 1.33 1.79 1.51 1.11 1.23 Hybrid Qwc - 1.77 - 1.92 - 1.55 - 1.03 1.26 Qza 1.62 1.66 - 1.45 1.53 1.35 1.31 1.17 1.22 1.21 Te1eo- ~rlllus oceanicus

Qayr 1.18 1.09 Qh 2.53 - 2.56 - 1.27 1.15 1.20 Qn 2.16 - 4.39 1.23 Hybrid Qayrh - 1.87 - 2.26 3.49 - 1.38 1.13 Qhayr - 1.73 2.02 2.07 2.64 2.15 1.08 - 2.82 - 1.03 - 1.17 1.12 Table 1 - continued

C1assif Total 1ength (~) T.C.L. cation l II III IV V VI VII VIII IX X XI XII XIII in,u

Te1eo gryllus commodua

Qa 1.96 2.28 2.68 3.02 3.08 3.41 3.52 3.78 4.27 4.56 5.03 5.81 7.86 12.94 115.94

Qc 2.52 2.68 2.99 3.18 3.24 3.47 3.63 3.82 4.26 4.28 4.26 4.56 6.14 25 0 67 113.63

Qd 2.11 2.45 2.98 3.31 3.61 3.85 4.00 4.35 4.86 4.86 5.22 5.94 9.73 17.18 J.32.09

Qk 1.72 2.08 2.41 2.79 3.08 3.22 3.43 3.44 3.66 3.79 4.15 5.08 7.50 15.25 108.49

Qt 2.52 2.76 3.36 4.14 4.41 4.71 4.95 5.19 5.25 5.62 6 .. 20 7.63 10.34 16.20 151.06

Qw 2.22 2.47 2.61 2.84 3.16 3.20 3.31 3.73 4.22 4.46 4.74 4.14 '" 7.90 16.91 115.05

Qz 2.20 2.42 2.72 3.19 3.32 3.42 3.67 4.10 4.39 4.52 4.62 5.36 8.06 15.92 120.78 Hybrid

Qwc 1.80 2.19 2.26 2.55 2.62 2.78 2.79 2.98 3.06 3.23 3.27 3.82 5.54 12.12 90.20

Qza 2.06 2.52 3.00 3.21 3.42 3.64 3.76 4.03 4.26 4.63 4.91 5.84 8.09 14.29 121.31 Te1eo gryllus oceanicua

Qayr 2.36 2.57 2.77 3.01 3.20 3.35 3.50 3.64 3.82 3.94 4.45 4.67 6.71 "15.60 111.32

Qh 2.40 2.79 3.04 3.45 3.65 3.81 3.86 4.08 4.45 4.61 5.12 6.00 7.95 18.14 128.60

Qn 2.52 2.73 2.91 3.03 3.21 3.30 3.46 3.66 3.83 4.00 4.27 5.16 5.90 17.38 113.65 Hybrid Qayrh 1.99 2.43 2.69 2.84 2.92 3.07 3.23 3.37 3.52 3.59 4.08 4.16 '" 4.75 16.92 102.32 Qhayr 2.22 2.63 2.99 3.29 3.54 3.91 4.17 4.24 4.28 4.86 4.95 5.76 7.84 17.94 127.40

'" unequa1 bivalent. Table 2. Frequenoy of four different types of ohromosomes and heteromorphio ohromosomes in different strains.

aoro- subtelo- submeta- meta- heter'omorphic centrio oentrio oentrio oentrio ohromosome

Teleogry11us oonunodus

Qa 7 2 2 3 Qo 10 3 0 l

Qd 3 6 2 3

Qk 3 6 3 2

Qt 2 5 3 4

Qw 3 5 2 3 l

Qz 4 3 4 3 Hybrid

Qwo 9 2 l 2

Qza 5 0 6 3 Teleogryllus ooeanious

Qayr 12 0 0 2

Qh 9 2 0 3

Qn 11 2 0 l Hybrid

Qayrh 8 3 1 1 l

Qhayr 4 6 0 4

Note: aorooentric: arm ratio=7 .0- 00 subte1ooentric: arm ratio=1.7-7.0 submetacentric: arm ratio=1.3-1.7 metacentric: arm ratio=1.0-1.3 io qQ.p,.. :Qîù .umn •

(Qz)

cillQuJa (Old ~) OUTH ISlAND ~.

Fig. 1 GEOGRAPHICAL DISTRJBUTION OF TELEOGRYLWS SPECiES Fig. 2 Idiogram of Adelaide (Qa) Strain of T. commodus.

Fig. 3 Idiogram of Victoria (Qc) Strain of T. commodus.

Fig. 4 Idiogram of Adelaide (Qd) Strain of T. commodus,

Fig. 5 Idiogram of Kaikoura, South Island (Qk) Strain of T. commodus.

O':"·'.'.' . 2

15 ]

o f'g.2

" 16

, . _ ~ - '~~;. .i~ ~~ t . :l, ?: ~'; .: ;1 _ 'f.!\~' • ~~ ç; ~~:: ': f, i! j" ~: J." ' 'u ",' • JI ' ë ; .~ ~ . ~ .~ ~ ~ . 6 - 6 ~. • • 'Z1 -,

,~'

Fig. 5 Fig. 4 . O·~ o Fig. 6 Idiogram of Tasmania (Qt) Strain of T. commodus.

Fig. 7 Idiogram of Western Australia (Qw) Strain of T. commodus.

Fig. 8 Idiogrrum of Auckland, North Island (Qz) Strain of ....T. commodus • Fig. 9 Idiogram of Qwc hybrid of T. commodus. 20 :' 20 "

15 1 15 11 1 lb 1 IIUIIIIIII

., 5 ' ~ 3t .,l, Fig. 6 o . .. Fig.7 o 11

15 '1; . î Ê

~ 7~ ;:~ ~ d'C, ;:., ';. '.' ~ ~ 5 ~., ,- ;' :,- '~ ,,' ' ,~ v "

~ " '''' ~2 .f' ~\~' 5 ~ 1! 'i i;, 0 ~. Fig.9

Fig. 8 o Fig. 10 Idiogram of Qza hybrid of T. cOllUnodus.

Figo 11 Idiogram of Ayr (Qayr) Strain of T. ooeanious.

Fig. 12 Idiogram of Tahiti (Qh) Strain of T. oceanicus. Fig. 13 Idiogram of Ingham (Qn) Strain of T. oceanicus.

Fig. 14 Idiogram of Qayrh hybrid of T. oceanicus.

Fig. 15 Id'iogram of Qhayr hybrid of T. oceanicus. _ HI __ IS- e E g E 0 : : IIIIIIIIIII !:' 111111111111

"0.10 fi9.11 o 0

1 - - ~ j 0 ]

~ 10 ·;11111111 ~

Fig. 15 Fig. 12 o o

20 20

.', .,

115 Ê 15' : 0

r'l) 15 0 1 CO "'1 1·1 \' • Fig. 16 Spermatogonial metaphase; the X chromosome appears as V-shaped and weak-staining.

Fig. 17 Oogonial metaphase; includes of a pair of X chromosomes.

Fig. 18 Interkinesis of spermatogonial cell; the X chromosome forms a separate vesic1e apart from the dividing nucleus.

Fig. 19 I~totic metaphase; the chromosomes are interconnected by fine threads.

Fig. 20 Metaphase II~ shmving two types of spermatocyte: the cell on the left with an X chromosome (arrow); in the cel1 on the right no X chromosome is present.

o '-," • .~

1,.

; 1 -'. ::,.11. -'.. ..l&fi1JI: - ,,-:-..#~:,:

'. ,""

Fig. 17

, '

Fig. 18 Fig. 19

Fie;. 20 Fig. 21 Polyploid cell of Adelaide (Qa) Strain of 1. commodus. Fig. 22 Adelaide (Qa) Strain of T. commodus, mitotic Metaphase.

Fig. 23 Victoria (Qc) Strain of T. oommodus, Metaphase l, showing the bivalent with a.ohromatic gap.

Fig. 24 Victoria (Qc) Strain of T. commodus, mitotio metaphase.

Fig. 25 Adelaide (Qd) Strain of T. commodus, Metaphase I; pairs XII and XIII appear as rTng-forms(arrows).

0-~'···.···, , Fig. 21

Fie. 22 Fig. 23

.:.

Fig. 24

Fig. 25 o

Fig. 26, Adelaide (Qd) Strain of T. commodus, hexaploid cell in Metaphase I; there are three X ohromosomes (arrows).

Fig. 27 Adelaide (Qd)Strain of T. commoüuo, mitotio metaphase.

Fig. 28 Kaikoura, South Island (Qk) Strain Ç>f T" comnlodus., Anaphase l, showing two ring-fom'. l.>:tvalents and the amall sphere bivalent (arrow).

Fig. 29 Kaikoura, South Island (Qk) Strnin of To commod~s, mitotic metaphase.

Fig. 30 Western Australia (Qw) Strain of T. commodua 1 Metaphase l, showing the hook-shaped heteromorphic chromosome.

0,.,",' Fig. 26

•. '.l..,

i:;~d!'~i:j~;::L~·~~::é..... ·;' ,, , . ~ Fig. 27 Fig. 28

, .

Fig. 29 Fie;. 30 Fig. 31 Western Australia (Qw) Strain of T. commodus, mitotic Metaphase.

Fig. 32 Auckland, North Island (Qz) Strain of T. commodus, Meta phase I; all the chromosome are homozygous.

Fig. 33 Auckland, North Island (Qz) Strain of T. commodus, mitotic Metaphase. Fig. 34 Auckland, North Island (Qz) Strain of T. commodus, Meta phase II, showing thirteen pairs of autosomes and an X chromosome (arrow).

Fig. 35 Qwc hybrid of T. ~ommodus, Metaphase l, showing that the smullest pair Y bivalents (arrow) separate faster to the poles than other bivalents.

~n 1 1 1

Fig. 31 Fig. 32

'-'1 >;,)"

k1 _ iii. Fig. 33

Fig. 34

".' .' , .. ., "1. 1 $" " ..~~; ~

}i'ig. 35 :'\..... C). ~ ,

Fig. 36 Qwo hybrid of T. oommodus, Metaphase l, showing double heteromorphic Chromosome pairs (III and XII). Fig. 37 Polyploid oeIl of Qwc hybrid of 1. commodus. Fig. 38 Qwc hybrid of !. oommodus, polyploid oeIl of peritoneal sheath.

o ·Fig. 36

~ , . 1

"-'--"'!,.". ."

Fig. 37

. ,....

Fig. 38 Fig. 39 Qwc hybrid of T. oommodus, polyploid oeIl of fat tissue.

Fig. 40 Qwo hybrid of T. oommodus, mitotic metaphase.

Fig. 41 Qwk hybrid of T. commodus, Metaphase l, showing the abnormal structure of ohromosomes. .

Fig. 42 Qwk hybrid of T. commodus, Prophase l; fourteen bivalents can be seen. -

o Fig. 39 Fig. 40

'Fig. 41

1 1 . f·

1 >" r 1

Fig. 42 A,' ~

Fig. 43 Qza hybrid of T. commodus, Anaphase II. Fig. 44 Qza hybrid of T. commodus, mitotic metaphase.

Fig. 45 Qza hybrid of T. commodus, Metaphase l.

Fig. 46 Ayr (Qayr) Strain of T. oceanicus, Metaphase l.

Fig. 47 Ayr (Qayr) Strain of T. oceanicus, Metaphase Ii achromatic gnpsoccur in sorne bivalents. Fig. 48 Ayr (Qayr) Strain of !. oceanicus, mitotic metaphase.

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',,~,.'; . , " ,,' '.. "~~:~,.,,,,~. ,:.) """C";~f~~~;,~.. ,.;,c,;-, . '" . ';-;.. '''.,jI , ~ ," ;~]~~st~~;~r;;i);;!'::~!·· .'; Fig. 44 Fig. 43

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Fig. 45 Fig. 46

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ï, ufo.J" > 'dl'Î ... : ' ' 1'" t 1. 1 r :.11 ~.;..----~~' Fig. 47 Fig. 48 A.. ·· .... ' V

Fig. 49 Tahiti (Qh) Strain of T. ooeanious~ Metaphase Ii all the bivalents are homozygous.

Fig. 50 Tahiti (Qh) Strain of T. ooeanious, mitotio mataphase.

Fig. 51 Ingham (Qn) Strain of T. ooeanious~ polyploid oell in mitotio metaphase. Fig. 52 Ingham (Qn) Strain of- !. ooeanious, Metaphase l, showing the unequal bivalent and the aohromatio gap.

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Fig. 49 Fig. 50

l<'ig. 51

'i.

Fig. 52 Fig. 53 Ingham (Qn) Strain of T. oceanious, Metaphase I; achromatic gaps appear at two ends of the bivalent (arr~w).

Fig. 54 Ingham (Qn) Strain of !. oceanicus, mitotic metaphase. Fig. 55 Qayrh hybrid of T. oceanicus, Metaphase l, showing triple heterozygotes. -

Fig. 56 Qayrh hybrid of T. oceanicus, showing three kinds of achromatic ga~s occurring in Metaphase I: (a) bivalent with a achromatio gap at one end; (b) attenuation of the under stained segment due to centric pull; (c) bivalent with a pair of achromatic gaps. Fig. 57 Qayrh hybrid of !. oceanicus, mitotic metaphase.

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r", .." .11:);f ün a b

Fig. 56 Fig. 54

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}'iC;. 55 Fig. 57 Fig. 58 Qhayr hybrid of T. oceanicus; Metaphase 1; bivalents appear as lampbrÜsh chromosome; achromatic gaps occur.

Fig. 59 Qhayr hybrid of T. oceanicus, 1~taphase 1; bivalents appear as lampbrüsh chromosome; achromatic gaps occur.

Fig. 60 Qhayr hybrid of T. oceanicus, Metaphase l, showing single heteromorphic pair (arrow ).

Fig. 61 Qhayr hybrid of T. oceanicus, mitotic metaphase.

o Fig. 58

Fig. 60

., .. 1

Fie. 61 Fig. 59 c

Fig. 62 Interspecific hybrid Qth, ProphaGe l, showing many unconnected univalents.

Fig. 63 Interspecific hybrid Qth, Metaphase l, chromosomes showing slight lampbrush structure.

Fig. 64 Interspecific hybrid Qth, Metaphase 1; supernumerary chromo somes occur (arrow).

Fig. 65 Interspecific hybrid Qth, Anaphase I, showing a single bridge.

( li'ig. 62

Fig. 64

Fig. 65 Fig. 66 Interspecific hybrid Qth, telophase I; sorne ohromosomes remain around the equator region.

Fig. 67 Interspeoific hybrid Qth, after meiotic division; sorne chromosomes li~ outside the daughter nucleus.

Fig. 68 Interspecific hybrid Qth, showing the ab normal size of the spermatid which is two or. more times as large as normal.

Fig. 69 Interspecific hybrid Qth, pol~~loid cell in mitotic metaphase.

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Fig. 66 Fig. 67

Fig. 68

Fig. 69 male female

Fig. 70 Mitotic metaphase, showing the difference between male and female, t'he female having a pair of homologous X chromosomes and the male only a single X ohromosome.

13A+X MALE: 2n=27 26A+XO / "" 26A + XX FEMALE '" 13A+O

13A+X / FEMALE: 2n=28 26A + XX 26A + XO MALE

"'" 13A + X /

Fig. 71 Sex-determination of Te1eogry11us species. Fig. 72 Adelaide (Qd) Strain of T. commodus J Metaphase l, showing the abnormal configuration of bivalents.

Fig. 73 Tasmania (Qt) Strain of T. commodus, Metaphase l, showing t'Wo ring-fm'm bivalents "'[pairs XII and XIII).

Fig. 74 Tasmania (Qt) Strain of T. commodus, mitotic metaphase. Fig. 72 Fig. 73

Fig. 74