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 poly- ploidy 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