ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672174

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The nature of hemolymph ecdysteroids was analyzed by high performance liquid chromatography-radioimmunoassay, during the two main phases of the reproductive cycles ofLabidura riparia.20-hydroxyecdysone and ecdysone were present together with polar and apoiar products.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672175

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This comparative study on the fecundity and age structure of the isopodMesidotea entomon(L.) from the Canadian western Arctic is one of the few studies on this species in it's two distinct habitats. In the marine population, year class segregations varied in density both in time and space. In contrast, the freshwater population remained relatively stable. Trimodal/bimodal size groupings suggests that this species takes 2–3 years to reach sexual maturity. Sexual size dimorphism in which the male is the larger sex was evident in both populations. The marine isopods sexually matured at a larger body size than those in freshwater and females produced larger and a greater number of eggs per unit length than those in freshwater. Fecundity was positively correlated with size.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672176

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

WhenMusca domesticafemales were maintained on sugar, most did not develop their ovarian follicles past stage 4. However, a 4 h pulse feeding of protein diet to these flies stimulated ovarian maturation and increased haemolymph ecdysteroid and vitellogenin levels. Ecdysteroid levels were significantly higher than in the the sugar-fed flies within 8 h of protein feeding, reaching a peak of 36 pg/ul at 28 h, and then decreased to starting levels by 52 h. The higher ecdysteroid concentrations were found in samples from houseflies that had stage 5 and 6 ovaries. Decreasing levels of ecdysteroid were associated with flies that had ovarian stages of 7 through 9. Diet influenced the concentration of specific ecdysteroids in the haemolymph. Pulse feeding protein increased the concentration of RIA-positive material that co-migrated on HPLC with ecdysone by 13 fold, but had no effect on the concentration of the material that co-migrated with 20-hydroxyecdysone. The concentrations of polar materials and RIA-positive materials co-migrating with 20, 26-dihydroxyecdysone and makisterone A, also increased after protein feeding. Vitellogenin levels were significantly higher than the controls by 12 h after protein feeding, reached a peak of 16 ug/ul at 20 h and then decreased to control levels by 52 h. Significant ovarian development was noticed by 8 h after protein feeding and required 114 h for completion.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672177

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Antiserum was raised in a rabbit against the purified androgenic gland hormone (AGH) ofArmadillidium vulgare.The specificity of the antiserum was confirmed by immunoblotting and by absorption of the biological activity of AGH. The immunological activity measured by ELISA correlated well with the biological activity of AGH. It is therefore possible to measure AGH by immunoassay. The immunoassay, which is time-saving and avoids the handling problems of the bioassay was used to measure seasonal variation of AGH content in male reproductive organs. Lack of immunological crossreactivity between preparations from different isopod species supported former results on biological species-specificity.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672178

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Spermducts from post-diapausingHeliothis virescenspupae developed to enlarged contractile capsulesin vitroin the presence of 20-hydroxyecdysone when naturally conjoined to the testes. However, isolated spermducts did not develop in 20HE unless co-cultured with testis sheath or fat body tissue. Aqueous extracts of testis sheath or fat body which had been maintained in 20HE media for 24 hours prior to extraction, promoted similar development in isolated spermductsin vitro.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672179

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We investigated the maturation divisions of two obligate parthenogenetic natural interspecific hybrids: the diploidB. whiteiand the triploidB. lynceorum. B. whiteishows two maturation divisions which produce 4 viable haploid nuclei. At the telophase II two non-sister nuclei come into contact and fuse to restore the diploid chromosome number and the maternal genetic structure. On the other hand, in the triploidB. lynceorum, pachytenic oocytes undergo an extra DNA doubling which allows the formation of a somatic number of autobivalents. Two divisions in rapid succession result in a pronucleus with the somatic number of unistranded chromosomes and two quickly degenerating polar bodies: this mechanism maintains the maternal cytological and genetic structure in the offspring.

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672180

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672181

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672182

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0792-4259    

DOI:10.1080/07924259.1991.9672173

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor