Library

X
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
    A review of factors governing the distribution of two closely related corixids in the saline lakes of British Columbia (1983)
    Springer
    Hydrobiologia 105 (1983), S. 143-154 
    Details
    ISSN: 1573-5117
    Keywords: saline lakes ; ecology ; physiology ; Hemiptera ; Corixidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two closely related species of Cenocorixa inhabit saline lakes in British Columbia. C. bifida lives in lakes with a conductivity of 20 to 20 000 µS cm-1, while C. expleta occurs in lakes with a conductivity ranging from 5 000 to 30 000 µS cm-1. The factors limiting the differential distribution of these species in higher salinities, and those governing the exclusion of C. expleta in low salinities have been studied. Mortality experiments, and an investigation of osmotic and ionic balance, indicate that the two species differ in their ability to tolerate high salinity: these data correlate with the limits computed from field data and suggest that the differential distribution in the high saline lakes is because of physiological differences. However, these same data indicate that both species have a similar ability to live in low salinity lakes. Although C. expleta does not occur in such lakes, it is physiologically capable of doing so and has been reared in freshwater. It is proposed that ecological rather than physiological factors exclude C. expleta from low salinity waters. Competitive exclusion by C. bifida might be suggested, but available data do not support this. A study of life cycle phenology, fundamental food niche and realized feeding niche of the two species shows that these are not significantly different. No interactive segregation is evident in sympatry, and so competitive exclusion of C. expleta in freshwater is unlikely. Hence, other biological factors in fresh and low salinity water have been investigated. A marked difference in susceptibility to mite parasitism of the species has been discovered. Although both C. bifida and C. expleta are parasitized by larval Eylais and Hydrachna, C. expleta appears unable to survive such parasitism. It is suggested that this is the biological factor that excludes C. expleta in the fresh and low salinity lakes where water mites are abundant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025184
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Sequestration of cardenolides inOncopeltus fasciatus: Morphological and physiological adaptations (1986)
    Springer
    Journal of chemical ecology 12 (1986), S. 1171-1187 
    Details
    ISSN: 1573-1561
    Keywords: Hemiptera Heteroptera ; Lygaeidae ; Oncopeltus fasciatus ; Asclepiadaceae ; cardenolides ; sequestration ; morphological adaptations ; physiological adaptations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The morphological and physiological adaptations associated with sequestration of cardenolides by the lygaeidOncopeltus fasciatus are summarized and discussed. Cardenolides are efficiently accumulated inO. fasciatus; however, the insect does not appear to suffer any physiological cost as a result of handling large amounts of these plant toxins. Morphological adaptations of the insect include a modified integument composed of a double layered epidermis with an inner layer (the dorsolateral space) specialized for cardenolide storage. Special weak areas of the cuticle are found on both the thorax and abdomen, which rupture when the insect is squeezed, resulting in the cardenolide-rich contents of the inner epidermal layer being released onto the body surface in the form of discrete spherical droplets. Physiological adaptations include selective sequestration of food plant cardenolides, concentration of cardenolides in the dorsolateral space, passive uptake of cardenolides at the gut and dorsolateral space requiring little energy output, reabsorption of secreted cardenolides by the Malpighian tubules, high in vivo tolerance to cardenolides, and the presence of cardenolide-resistant Na,K-ATPases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01639003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Selective sequestration of milkweed (Asclepias sp.) cardenolides inOncopeltus fasciatus (Dallas) (Hemiptera: Lygaeidae) (1985)
    Springer
    Journal of chemical ecology 11 (1985), S. 667-687 
    Details
    ISSN: 1573-1561
    Keywords: Cardenolide metabolism ; cardenolide excretion ; cardenolide sequestration ; Hemiptera ; Lygaeidae ; Oncopeltus fasciatus ; milkweed bug ; Asclepias.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The cardenolide content of the gut, wings, and fat body ofOncopeltus fasciatus was examined. The female fat body contained 4–5% of the total cardenolide content of the insect. The cardenolide content of male fat body, and gut and wings of both sexes was below the detection limit of the cardenolide assay. Thin-layer chromatography was used to determine the cardenolide array of various tissues and secretions ofO. fasciatus reared on seeds of a single species of milkweed (A. Speciosa) and adult extracts and dorsolateral space fluid ofO. fasciatus reared on seeds of two species of milkweed with different cardenolide arrays (A. speciosa andA. syriaca). Our results indicate that cardenolides are not sequestered in the insect simply on the basis of polarity and that metabolism and differential excretion of cardenolides are involved in the sequestration of cardenolides inO. fasciatus. The similarities in the cardenolide profiles ofO. fasciatus reared on different food sources, and tissues ofO. fasciatus reared on a single food source indicates that there is regulation of the cardenolide array inO. Fasciatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00988575
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...