ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Taste Sensitivity of Insect Herbivores to Deterrents is Greater in Specialists Than in Generalists: A Behavioral Test of the Hypothesis with Two Closely Related Caterpillars (2000)

Bernays, E. A. ; Oppenheim, S. ; Chapman, R. F. ; [et al.]

Springer

Journal of chemical ecology 26 (2000), S. 547-563

add to mindlist on the mindlist

Details

ISSN: 1573-1561

Keywords: Heliothis virescens ; Heliothis subflexa ; caterpillar ; diet breadth ; deterrent compound ; feeding behavior ; postingestive toxicity ; plant secondary metabolite

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology

Notes: Abstract Sensitivity of caterpillars of Heliothis virescens, a generalist, and H. subflexa, a specialist, to eight different plant secondary compounds was examined behaviorally. The compounds were nicotine hydrogen tartrate, hordenine, caffeine, sinigrin, linamarin, arbutin, chlorogenic acid, and salicin. All compounds deterred feeding, at least at the higher concentrations, but the generalist was less affected than the specialist. Thus the hypothesis that specialists have greater sensitivity to deterrents than generalists was supported. In most cases deterrence occurred on first encounter, indicating that the response was sensory; in some cases short-term postingestive effects also appeared to play a role. The larger quantities of deterrent-containing food ingested by H. virescens sometimes resulted in measurable postingestive effects during the second control test. This did not occur in H. subflexa, which more commonly rejected the deterrent-containing food on first contact. The contrast between the species is discussed in relation to tradeoffs involved in different diet breadths.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1005430010314

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Volume changes accompanying thermal denaturation of deoxyribonucleic acid. II. Denaturation at alkaline pH (1970)

Chapman, R. E. ; Sturtevant, J. M.

New York : Wiley-Blackwell

Biopolymers 9 (1970), S. 445-457

add to mindlist on the mindlist

Details

ISSN: 0006-3525

Keywords: Chemistry ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: The change in apparent molal volume φ of DNA on thermal denaturation in carbonate buffer at pH 11.0 has been determined by the dilatometric method. It was found that φ increases sigmoidally during the helix-coil transition. Several methods, including a colorimetric technique that closely simulates the conditions used in the dilatometric experiments, were employed to estimate the protons lost by the DNA during the transition. These measurements indicated that the extent of the proton loss depends on the counterion present, increasing in the order Li+ 〈 Na+ 〈 K+ 〈 Cs+. The major part of the volume changes observed during the denaturation is due to the volume changes expected to accompany the transfer of protons from the bases guanine and thym ne to carbonate ions. As has been previously reported for the denaturation of DNA at neutral pH, the volume change directly due to the change in shape of the polymer molecules is so small as to be experimentally undetectable.

Additional Material: 7 Ill.