WILBERT

Wildauer Bücher+E-Medien Recherche-Tool

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 430 (2004), S. 676-679 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Kin selection theory predicts that individuals will show less aggression and more altruism towards relatives. However, recent theoretical developments suggest that with limited dispersal, competition between relatives can override the effects of relatedness. The predicted and opposing ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 406 (2000), S. 183-186 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] An important transition in insect life-history evolution was the shift from a solitary existence to living in groups comprising specialized castes. Caste-forming species produce some individuals that reproduce and others with worker functions that have few or no offspring. Morphologically ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 360 (1992), S. 254-256 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] C. floridanum is a small wasp that parasitizes the eggs of the moth Trichoplusia ni. Wasps produce all-male or all-female broods by laying one egg per host and mixed broods by laying two eggs (one male and one female)5. After parasitism the moth host egg hatches and the larva develops to its final ...
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0739-4462
    Keywords: development ; embryogenesis ; gene expression ; Trichoplusia ni ; Lepidoptera ; Noctuidae ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Changes in protein and mRNA synthesis during embryonic morphogenesis of the polyembryonic parasitoid Copidosoma floridanum were characterized by 1- and 2-dimensional gel electrophoresis and quantified by scanning densitometry. Analysis of protein synthesis at different developmental stages indicated that embryonic molecular changes occurred at 36 h of the host's fourth stadium. These changes included decreased expression of 51 and 104 kD (D) proteins and increased expression of 22, 22.5, and 24 kD (D) proteins. Similarly, analysis of in vitro translation products indicated increased transcription of mRNA encoding 16 and 49 kD proteins in embryos dissected at 36 h of the host's fourth stadium. The stage-specific changes in transcription and translation corresponded to the blastula stage of embryonic development and arose several hours before the initiation of embryonic morphogenic events associated with larval pattern formation. Application of the JH analogue methoprene at times that block morphogenesis but not blastula formation did not block the stage-specific synthesis of any proteins. In contrast, neck ligation of hosts at times that block blastula formation and morphogenesis inhibited the synthesis of the 24 kD protein that was normally expressed at the blastula stage.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0739-4462
    Keywords: polydnavirus ; hemolymph ; soybean looper ; braconid ; parasite ; wasp ; Lepidoptera ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The venom of Microplitis demolitor consists of a mixture of proteins. On native PAGE gels three major proteins designated a, b, and g were detected, while on SDS-PAGE gels two major proteins of Mr 64.5 and 30.8 kD and several minor proteins were detected. No proteins smaller than Mr 30.8 kD were present. Murine monoclonal antibodies were generated against different venom components. Analysis by Western blot of venom proteins separated on native and SDS-PAGE gels confirmed that antibodies from seven hybridoma lines recognized venom components. Two of the seven hybridoma lines reacted specifically with protein g on native PAGE gels and the Mr 30.8 k protein on SDS-PAGE gels, while four other lines cross-reacted with these and other venom proteins. The final hybridoma line reacted with protein a when venom was separated on native PAGE gels and an array of proteins when venom was separated on SDS-PAGE gels. Using an enzyme-immunoassay and specific monoclonal antibodies, M. demolitor females were estimated to inject 0.02 - 0.05 venom gland reservoir equivalents into its host, Pseudoplusia includens, at oviposition. Venom proteins persisted in host hemolymph for 6 - 12 h before dropping to undetectable levels. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 7 (1994), S. 895-897 
    ISSN: 1572-8889
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 71 (1994), S. 185-192 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Pyralidae ; Indianmeal moth ; semiochemicals ; attraction ; oviposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Substrates contaminated by wandering fifth instar larvae ofPlodia interpunctella (Hübner) (Lepidoptera: Pyralidae) elicit oviposition by conspecific female moths, and larval rearing diet enhances oviposition and also induces upwind flight. Two-choice oviposition assays determined that four-day-old gravid femaleP. interpunctella preferred to lay eggs on dishes containing cornmeal-based rearing diet compared to empty dishes. Pieces of cheesecloth contaminated by fifth instar larvae elicited more oviposition than untreated cheesecloth or dishes with food. The combination of larval contamination and food was preferred over food only or larval contamination only in both two- and four-choice experiments. The factor(s) in larval contamination responsible for eliciting oviposition in female moths was extracted in hexane, confirming that organic semiochemicals are responsible for the effect. The oviposition-eliciting activity of larval contamination was retained on cheesecloth for up to 30 days following treatment with larvae, suggesting the active component(s) is stable and of low relative volatility. In two-choice windtunnel bioassays female moths initiated flight only when rearing food was present in one of the treatments, and they displayed the highest landing responses to a combination of larval contamination and food. Earlier work onP. interpunctella and related pyralid species found that larval contamination due to secretions from the mandibular glands acted as both a spacing pheromone for wandering larvae and as a kairomone for host-seeking parasitoid wasps. The present study suggests that the same or a similar secretion acts as an oviposition-eliciting pheromone for conspecific females.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 93 (1993), S. 343-348 
    ISSN: 1432-1939
    Keywords: LMC ; Polvembryony ; Primary and secondary sex ratios ; Oviposition decisions ; Host encounter rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Copidosoma sp. is a polyembryonic encyrtid wasp which parasitizes isolated hosts. Most broods of this wasp are unisexual, but some contain both sexes and the secondary sex ratio of these is usually highly female biased. The overall population secondary sex ratio is female biased. Walter and Clarke (1992) argue that because the majority of individuals must mate outside the natal patch, the bias in the population secondary sex ratio contradicts predictions made by Hamilton's (1967) theory of local mate competition (LMC). We suggest that the primary sex ratio is unbiased and that Walter and Clarke's results do not cast doubt on LMC. Instead these results imply that ovipositing females make a combined clutch size and sex ratio decision influencing whether individuals developing from a particular brood will outbreed or largely inbreed; for each case the predictions of LMC theory are not violated. If this interpretation is correct, what is of interest is the basis on which this decision is made rather than the population secondary sex ratio. We show that host encounter rate influences the proportions of mixed and single sex broods laid by Copidosoma floridanum, a related polyembryonic parasitoid. Among single-sex broods the primary sex ratio is female biased, but our results are in agreement with LMC theory since offspring developing from these broods will probably mate with siblings from adjacent hosts. We consider the egg load of females to be of major influence on oviposition behaviour, and that the mating structure of parasitoid offspring, potentially differential costs of male and female broods and the natural distributions of hosts both at oviposition and eclosion, require further study.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 109 (1997), S. 547-555 
    ISSN: 1432-1939
    Keywords: Key words Sex ratio ; Parasitoid ; Reproductive decisions ; Virgin oviposition ; Bracon hebetor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In haplodiploid organisms such as parasitic wasps, substantial oviposition by females without sperm is predicted to cause mated females to bias their offspring sex ratios towards daughters. The effect of the production of sons by unmated and sperm-depleted (constrained) females on sex allocation by mated females was studied in two populations of the parasitic wasp Bracon hebetor over 3 years. B. hebetor females who depleted their sperm reserves from prior matings rarely remated and became constrained to produce only sons. Constrained females readily oviposited and produced clutches similar in size to those produced by mated females. Although the fraction of constrained females in the population varied considerably between sites and sampling dates, it was usually high enough to favor the production of female-biased sex ratios by mated females. Mated females consistently produced female-biased sex ratios. However, we found no evidence that the sex ratios produced by mated females from the field shifted in relation to the proportion of constrained females in the population. Females held with males or held in isolation also produced female-biased sex ratios. These findings suggest that, in B. hebetor, mated females produce sex ratios that reflect the average fraction of constrained females over evolutionary time.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0739-4462
    Keywords: development ; endocrine ; hormone ; embryogenesis ; host ; parasitoid ; Lepidoptera ; Hymenoptera ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Trichoplusia ni parasitized by Copidosoma floridanum weighed more in the fourth and fifth instar than unparasitized controls. While parasitized and unparasitized fourth-instar larvae molted at the same time, parasitized fifth-instar larvae ceased feeding and initiated wandering 1 day later than unparasitized fifth-instar larvae. Measurement of hemolymph ecdysteroid, juvenile hormone esterase (JHE), and protein titers suggested that the delay in wandering had an endocrinological basis. Ecdysteroid titers of parasitized and unparasitized fourth-instar larvae were similar, but the ecdysteroid titer in parasitized fifth-instar larvae rose about 24 h later than in unparasitized fifth-instar larvae. Two major peaks of JHE activity occurred in unparasitized fifth-instar larvae, but only one occurred in parasitized fifth-instar larvae. JHE activity coincided on the first day of the fifth instar (L5D1) in both parasitized and unparasitized fifth-instar larvae; however, activity peaked and fell later in parasitized individuals. Few differences were noted in the hemolymph protein levels of parasitized and unparasitized hosts. Ligation of parasitized T. ni between the head and prothorax adversely affected C. floridanum development. Ligation before or immediately after ecdysis to the fourth instar inhibited differentiation of the C. floridanum morulae. C. floridanum ecdysed to the second instar or pupated in hosts ligated prior to wandering in the fifth instar, but the number of progeny that pupated and emerged as adult wasps was reduced relative to unligatured controls.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...