Calliphora Stygia Research Articles

IDENTIFICATION OF EARLY IMMATURE STAGES OF SOME COMMON QUEENSLAND CARRION FLIES

AbstractEggs of Calliphora augur (Fabricius), Calliphora stygia (Fabricius), Lucilia cuprina (Wiedemann) and Australophyra rostrata (Robineau‐Desvoidy) are described and illustrated in detail by scanning electron micrographs.First and second instar larvae of the above species along with those of Chrysomya rufifacies (Macquart), Chrysomya varipes (Macquart), Chrysomya saffranea (Bigot), Chrysomya nigripes Aubertin and first instar larvae of two species of sarcophagid (Trieholioproctia sp. and Parasarcophaga crassipalpis) are described, illustrated and compared with each other by means of keys. Particular attention is paid to the morphology of the pharyngeal skeleton and distribution of spines and, in the second instar larvae, to the morphology of the posterior spiracles and the number of processes on the anterior spiracles in addition to the characters mentioned previously.

The transmission of information by first and second order neurons in the fly visual system

1. Random (white noise) fluctuations of both point and wide field light sources were presented to eyes of the fly,Calliphora stygia. At the same time, intracellular recordings were made from photoreceptor cells and from large monopolar cells (LMCs) in the lamina ganglionaris. 2. Fourier analysis was used to determine the linear frequency response functions and coherence functions between the input light fluctuations and the resultant fluctuations in membrane potentials of the two types of cells. 3. The frequency response function of the receptor-to-LMC pathway was estimated by dividing the overall light-to-LMC frequency response function by the light-to-receptor frequency response function. For small signal conditions this function is primarily a phase shift of 180° (inversion) and some increase in sensitivity with frequency. 4. Comparison of results obtained with point and wide field stimuli did not reveal any significant differences between the frequency response functions of receptors or LMCs to either stimulus. No evidence of lateral interaction between receptors or LMCs was found. 5. For a linear system the coherence function provides a measure of the signal-to-noise ratio as a function of frequency. Comparison of the coherence functions obtained from receptors and LMCs showed that there is no significant improvement or deterioration in the signal-to-noise ratio as the signal passes from receptors to LMCs.

Nature, origin and fate of major haemolymph proteins in Calliphora

During the development of the brown blowfly, Calliphora stygia, four quantitatively major proteins are found in the plasma of haemolymph. These four proteins are immunologically, electrophoretically, and structurally distinct and do not share any common subunits. In the late feeding larva the total protein concentration of plasma is 200 mg/ml and the haemolymph volume is 53 μl. At pupariation these values are 108 mg/ml and 40 μl, falling in the newly emerged adult to 29 mg/ml and 22 μl respectively. Of the three major protein species (arbitrarily designated A, B, C) in larval and adult plasma, only protein A appears to be synthesized in both a larval and an adult tissue. Protein D is found in adults at emergence and represents an exclusively adult product.

Metabolism of some possible ecdysone precursors in Calliphora stygia

A study has been made, using Calliphora stygia at the time of puparium formation, of the incorporation of a number of labelled sterols into β-ecdysone. [1 α- 3H]-Cholesterol and [4- 14C]-cholesterol are incorporated to a similar extent (0·01-0·02%). [1- 3H]-7-Dehydrocholesterol is better incorporated (0·025%) than cholesterol while [1 α- 3H]-cholesterol sulphate, (22R)-22-hydroxy-[22- 3H]-cholesterol, and 25-hydroxy-[26- 14C]-cholesterol are not incorporated to a significant extent.

Constituents of the Boll Weevil.1 Vii. the Molting Hormone: Isolation Studies2

The initiation of the molting process in insects has been attributed to a class of steroids known as ecdysones. These compounds were isolated and tentatively identified from pupae of the silkworm, Bombyx mori (L.) (Butenandt and Karlson 1954, Karlson and Hoffmeister 1963); adults of the socalled moroccan locust, Dociostaurus maroccanus (Thunberg) (Stamm 1958); tobacco horn worm, Manduca sexta (L.) (Kaplanis et al. 1966b); blowfly, Calliphora stygia (F.) (Galbraith et al. 1969), and the oak silkworm, Anthcraea pernyi Guerin-Men©ville (Horn et al. 1966). Subsequent work then led to structure determination (Kaplanis et al. 1966b, Hocks and Wiechert 1966, Hoffmeister and Gruetzmacher 1966, Karlson et al. 1965, Huber and Hoppe 1965) and synthesis (Siddall et al. 1966, Kerb et al. 1966, Huppi and Siddall 1967, Kerb et al. 1968). The major steroid hormones isolated and characterized from insect sources are α-ecdysone and 20-hydroxyecdysone; the ratios of the two vary among species. Another ecdysone, 20,26-dihydroxyecdysone, that was isolated from pupae of the tobacco hornworm (Thompson et al. 1967) may represent an intermediate in the degradative pathways of the ecdysones. The possible biosynthetic and degradative pathways of the ecdysones are discussed in a review by Robbins et al. (1971).

An improved Calliphora bioassay for insect moulting hormones.

SummaryThe bioassay of insect moulting hormones is facilitated by use of the Australian brown blowfly, Calliphora stygia, instead of C. vicina, the species commonly employed. The late larval development of C. stygia is more readily synchronized than that of C. vicina, and the necessary treatment is described. With C. stygia, the yield of test‐abdomens for use in the bioassay is 60–80% when larvae are kept at an elevated oxygen tension after ligation. The best yield of test‐abdomens obtained with C. vicina is approximately 40%, whether the larvae are kept in air or in oxygen.Dose‐response data for crustecdysone administered to test‐abdomens of C. stygia and C. vicina are presented. Sensitivity of tbe bioassay depends in part on the Volume of test solution injected. The useful dose‐range for the moulting hormones bioassay in C. stygia corresponds to approximately 10–75 ng. crustecdysone/abdomen. In C. vicina the useful range is the equivalent of approximately 5–50 ng. crustecdysone/abdomen.

Developmental changes in the major inclusion bodies of polytene nuclei from larval tissues of the blowfly, Calliphora stygia.

The major ribonucleoprotein inclusion bodies of the polytene nuclei from larval ventral nephrocytes, Malpighian tubules, pericardial cells, fat body and salivary glands of Calliphora stygia show characteristic developmental patterns at the light microscope level. Three morphologically and developmentally distinct classes of nuclear inclusions occur in these tissues. In fat body and salivary gland nuclei, morphological changes in the inclusion material can be correlated with the pattern of protein synthesis during the third larval instar, and with conspicuous changes in chromosome morphology. The appearance of cytologically diverse nuclear inclusions, in an ordered tissue-specific sequence, may thus reflect differential activation of the genome.

The interpretation of puff patterns in polytene chromosomes

Criticism of the use of chromosomal puffing in dipteran polytene nuclei as an indicator of gene activity is examined in relation to the selection of experimental systems and the presumed range of synthetic activities carried out by each type of cell. A major criterion of selection has been the favourability of Chromosome morphology for cytological analysis. As a consequence, the proportion of the genome which may become activated in a range of functionally diverse cells appears to have been under-estimated. Comparative aspects of polytene chromosome behaviour in different tissues and at different stages of development are illustrated with reference to footpad and trichogen cells from pupae, and to salivary grand and fat body cells from larvae, of the brown blowfly, Calliphora stygia. Other problems of interpretation arising in studies of chromosomal puffing are briefly reviewed.

Ultrastructure of probable sites of release of neurosecretory materials in an insect, Calliphora stygia Fabr. (diptera)

The ultrastructure of some probable sites of release of materials from axons of neurosecretory cells is described. The sites comprise clusters of small pale vesicles adjacent to the plasma membrane with electron-dense material and neurosecretory granules associated with them. These sites were found in some axons in which the plasma membrane is adjacent to the basement membrane and in other axons in which the plasma membrane is contiguous with the plasma membrane of cells of the corpus allatum and with other axons containing neurosecretory granules.