摘要:

The corpora allata (CA) of azadirachtin (AZA)-induced over-aged 5th instar female nymphs ofLocusta migratoriawere relatively inactive during the first 20 days in the instar. They afterwards produced juvenile hormone (JH) IIIin vitro, coinciding with limited vitellogenic oocyte development. The basal rate of JH production and the length of the vitellogenic oocytes were lower in the over-aged nymphs, but the farnesoic acid (FA)-stimulated rate of JH production and volume of CA were higher than in normal adult females. Injection of massive doses of methoprene into the over-aged nymphs slightly enhanced vitellogenic oocyte development, which still remained incomplete. Chemical allatectomy by precocene III prevented, and injection of JH III or of methoprene restored, the limited vitellogenic oocyte development in the over-aged nymphs. Therefore, some factor other than JH shortage—possibly inadequate competence of the ovaries/ovarioles, would seem to limit vitellogenic oocyte development in over-aged nymphs.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672287

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Corpora allata from femaleBombus terrestris, incubated in a medium containing L-[methyl-3H]methionine, released three radiolabelled products, one of which was identified as JH-III by RPLC analysis. Two others did not correspond to any JH analogues or JH-related compounds, and they remain unidentified. Exogenous farnesol stimulated JH-III biosynthesis and suppressed the synthesis of the two unidentified products. Corpora allata activity was monitored throughout and after adult diapause. Rates of JH-III biosynthesis were low during prediapause and diapause. Corpora allata reactivation occurred several days after emergence from soil and thus seemed not to be involved in diapause termination processes. Experimental diapause breakdown revealed two phases in imaginaiBombusdiapause: diapause development and post-diapause quiescence. Carbon dioxide narcosis associated with 20°C, 13L/11D conditions provided rapid and reliable diapause termination in both diapause phases. The mode of CO2narcosis action is not mediated by corpora allata reactivation and remains to be elucidated.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672288

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Neuroendocrine controls of vitellogenesis, gonadotrophic cycles and ecdysteroid levels were examined inLabidura ripariausing microsurgical manipulations, hormonal treatments, enzyme immunoassay (EIA) and high performance liquid chromatography (HPLC). In normal females high levels of ecdysteroids occur both in ovaries and hemolymph at the end of each vitellogenic cycle. In allatectomized (CA−) andpars intercerebraliscauterized females (PI−) vitellogenesis is suppressed, and ovarian ecdysteroids are at a low level. Juvenile hormone (JH) treatments restore vitellogenesis and high ecdysteroid levels in both experimental cases.Pars lateraliscauterized females (PL−) display a continuous vitellogenesis; however, ecdysteroid levels are lower in ovaries and higher in hemolymph than in normal females. HPLC/EIA analysis of ovarian ecdysteroids was performed, and the effects of different hormonal treatments are described. Discussing the interactions between JH, ecdysteroids, gonadotrophic activity and neurosecretory centers, we point out the role of thepars lateralisin the regulation of ecdysteroid levels. Besides, we suggest that ecdysteroids exert a feed-back control onLabiduragonadotrophic cycles.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672289

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Hormonal control of egg development in the ixodid tickAmblyomma hebraeumKoch was investigated as follows: ovaries from small partially fed or fully engorged females were transplanted into the haemocoel of engorged females that were undergoing vitellogenesis; the transplants responded to this milieu by completing oocyte maturation. The following treatments all failed to stimulate egg development within eight days in small partially fed ticks: (a) slow fusion of 20-hydroxyecdysone (up to 7.2 μg) over 24 h; (b) topical application or injection of up to 50 μg juvenile hormone III; (c) topical application of 10 μg of methylfarnesoate and juvenile hormone III bisepoxide; (d) a combination of 20-hydroxyecdysone and juvenile hormone III. Also, none of the latter treatments accelerated oocyte maturation in engorged females. Injections (up to 100 μg per tick) or topical application (1 mg per tick) of precocene II did not inhibit egg development in engorged females which survived this treatment. Thus, although egg development inA. hebraeumis under hormonal control, the data fail to suggest a specific role for an ecdysteroid or juvenile hormone.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672290

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Fertilizing capacity of spermatozoa collected from various storage sites in the male and female squids were examined by inseminated eggs in the presence or absence of gelatinous substances of the oviducal gland origin. Over 90% of the eggs were fertilized by the spermatozoa collected from the female's seminal receptacle regardless of the presence or absence of the gelatinous substance. Elevation of the chorion and the formation of perivitelline space was observed only in the jellied eggs. All jellyless eggs without perivitelline space died in 4 days after insemination. Spermatozoa collected from the spermatophore in the male's accessory gland could fertilize the majority of the eggs. On the other hand, those from the male's vas deferens could fertilize only 30–50% of both the jellied and jellyless eggs. It may be concluded from these experiments that the gelatinous substance of the oviducal gland origin has nothing to do with fertilization. However, it is essential for the elevation of the chorion and the formation of the perivitelline space. It may also be concluded that squid spermatozoa become fertile before they are transferred to the female's seminal receptacle.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672291

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Resting O2consumption as measured by respirometry rises sharply immediately after feeding in females ofRhodnius prolixusand undergoes a slow decline after about the fourth day, returning to pre-feed levels by the tenth or twelfth day after feeding. The O2consumption of mated females remains slightly higher than that of virgin females during the period of egg production. Thus, virgin females, earlier shown to produce fewer eggs from a blood meal of equivalent size without gaining weight, do not maintain their weight by an elevated resting metabolism. The O2consumption of ovariectomized females, while not reaching the same level as normal females, exhibits the same sharp increase after feeding, but that increase is absent in allatectomized females. While these facts may indicate a role for juvenile hormone in controlling the level of oxidative metabolism, the effect of other hormones cannot be ruled out.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672292

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Mature spermatozoa ofNematogenia panamensis(Annelida: Oligochaeta, Ocnerodrilidae) from Madagascar were studied by electron microscopy. The spermatozoon is 35 μm long and shows the conventional clitellate sequence of acrosome, nucleus, middle piece and tail. The acrosome is asymmetric, showing an acrosome rod consistently bent to one side and probably exiting laterally for a short distance from the acrosome vesicle, only to re-enter apically. The middle piece consists of six mitochondria with the shape of a cylindrical sector and the tail is a flagellum with a 9+2 axoneme with two central tetragon fibers, surrounded for most of its length by glycogen granules. While the general features ofNematogeniaspermatozoon are undoubtedly of megadrile type, some characters, like the shortness of the acrosome and the basal chamber, indicate a plesiomorphic condition within the group. This is in good agreement with the proposed phylogenetic position of Ocnerodrilidae within the Oligochaeta.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672293

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The prothoracic gland of honey bee larvae was identified, and its developmental characteristics were assessed by a combination of histological and physiological methods. The reticulate gland is attached to the intestinal tract at the junction of the esophagus and midgut. Ultrastructurally prothoracic gland cells show the typical characteristics of ecdysteroid-producing cells, i.e., a deep plasma membrane reticular system and extensive smooth as well as rough endoplasmic reticulum. Small lipid vacuoles bounded by flattened SER sacs were found in considerable numbers shortly before commencement of ecdysteroid synthesis. An element apparently unique to prothoracic gland cells of honey bees are tracheoles, which penetrate deeply into the gland. Ecdysteroid production of isolated glands was monitoredin vitroby RIA analysis of released products. Developmental profiles for hormone production in prothoracic glands of queen and worker larvae showed a high correlation to caste-specific differences in hemolymph ecdysteroid titer. Control tissue did not liberate significant amounts of RIA-active material during decisive developmental phases.

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672294

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672295

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1993.9672296

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor