Genetics - Theses
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ItemCytogenetic and evolutionary studies on macropathinae (gryllacridoidea : orthoptera)(University of Melbourne, 1970)The Gryllacridoidea are a very ancient and diverse assemblage. One of the four families included in it, the Sohizodactylidae, is confined to the Old World, while the other three, Stenopelmatidae, Gryllacrididae and Rhaphidophorinae, have a world-wide distribution. The latter family Is divided into the subfamilies Ceuthophilinae from North and Central America, Rhaphidophorinae mainly from Europe and Asia, and Macropathinae with a circum-antarctic distribution. Up to date, less than one hundred species of Macropathinae have been described, the majority of them from New Zealand and the surrounding islands. Fourteen species were described from the East and South of Australia including Tasmania and Flinders Island. A few species are from the Southern cone of South America while only one species has been described from Africa, in Cape Town. The majority of these species are forest inhabitants with nocturnal habits. During the day they hide in dark and humid places like hollow logo and or crevices. Caves and tunnels make a suitable place for then to hide in and reproduce. Their density in those places is sometimes remarkable and hence their fame of being mainly cave inhabitants. To collect these insects in forest is more difficult due to the fact that their populations are more scattered. The Macropathinae, like the remaining rhaphidophorids, are wingless. Their body length range from less than 1 cm. to nearly 5 cm. The length from the tip of the antennae to the hind tarsi reaches 45 cm in Gymnoplectron giganteum (Richards 1962). Information on chromosome numbers and chromosomal sex-determining mechanisms in gryllacridids other than Macropathinae is summarised in Table I. According to these data, the chromosome number varies widely from family to family and even within families. The majority of these papers deal with chromosomes at metaphase, information about the fine structure of chromosomes at prophase being very scarce. In the present study a survey on the chromosomes and terminal abdominal segments within Macropathinae was undertaken in order to find possible phylogenetic relationships within the subfamily. Sometimes it was unavoidable to enter the taxonomic field. In this respect, only the genera Miotopus, Pleioplectron and Weta wore fully treated. When new genera end species were involved, a brief, preliminary description was included. Nearly seventy species were investigated, about half of them being new species. About a dozen New Zealand new genera were discovered as well. Approximately fifteen hundred specimens were handled from which nearly four hundred were cytologically investigated. The description of this amount of species will undoubtedly take a long time and falls outside the scope of the present study, which must be only considered a preliminary report.