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Development of first instar larvae of Gonia cinerascens, which rest in the muscles of host caterpillars, is triggered by the release of the host's ecdysteroids when the juvenile hormone is absent. Ecdysteroids act on the parasitoid directly and at the same time induce physiological and biochemical changes in the host, which are indispensable for the parasitoid's development. These changes do not occur when metamorphosis of the host is suppressed with the juvenile hormone. Normally the parasitoids initiate development at the larval-pupal transformation of the host, but under experimental conditions, they do so whenever a high ecdysteroid titre is coupled with the proper internal environment in the host, that is in decapitated caterpillars, isolated host abdomens, and when implanted into host pupae. Activated parasitoids moult into the second instar and migrate to the exuvial space of the host; this migratory behaviour is also triggered by ecdysteroids and may be induced experimentally in the first instar parasitoids. Unknown clues direct the migrating parasitoids under the wings and appendages of the host pharate pupal stage. The second instar parasitoids, which anchor to the integument of the host pupae, apparently develop independently of the host's hormones: they can produce third instar larvae, pupae, and adult flies when cultured in vitro. 相似文献
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Heiner Birkenbeil Manfred Eckert Prof. Dr. Manfred Gersch 《Cell and tissue research》1979,200(2):285-290
Summary Fixation of prothoracic glands of Galleria mellonella with a solution containing saponin permits immunocytochemical staining of the entire gland. By this means ecdysteroids were demonstrated electron microscopically to be present in the hyaloplasm and microtubules.Supported by Sächsische Akademie der Wissenschaften zu Leipzig 相似文献
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Summary The alary muscles of Locusta migratoria adults make up the major tissue of the dorsal diaphragm which separates pericardial and perivisceral sinuses in the abdomen. The alary muscles are striated with a sarcomere at rest measuring about 9 m. The Z-line has a staggered-beaded arrangement with A-bands and I-bands readily discernable. Thick myofilaments are surrounded by 10 or more thin filaments. The sarcoplasm has few mitochondria near the area of the Z-line, dyads are present and sarcoplasmic reticulum is poorly developed. Axons which innervate the alary muscle are either contained within invaginated folds of the sarcolemma of the muscle cells or the muscle cells send finger-like projections to envelop the axons. The synaptic terminals contain synaptic vesicles between 40 and 45 nm in diameter and a few electron-dense granules near or less than 170 nm in diameter. Away from synaptic terminals the axon profiles show few or no granules. The axons are accompanied everywhere by well-developed glial cells. This then is not typical neurosecretomotor innervation, however, the presence of electron-dense granules suggests the possibility of peptidergic neurotransmission. 相似文献
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Hiroshi Takeda 《Population Ecology》1979,21(1):120-134
The distribution pattern of ten species of Collembola was studied during the four years period from July 1971 to May 1975 in a pine forest soil. The distribution patterns were analysed for two scales of distribution, i. e., the distribution over the plot of 10×10 m2 and the micro-distribution within a block sample consisting of 36 contigious units each 2×2 cm2 in area, by applying the -m regression method. The fundamental pattern which appeared was quite similar for the species examined and individuals were aggregated in response to the heterogeneity of habitat conditions. The causes of aggregations were discussed with regard to some environmental factors. The relative abundances of 10 species within the collembolan community was examined in relation to the habitat utilization and the relative abundance was not related to the degree of aggregation but rather to the area occupied by individuals. This suggests that the more numerically abundant species tend to occupy broader micro-habitat. Biological meaning of aggregation was discussed in connection with the population biology and community organization of collembola. 相似文献
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