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  • 1990-1994  (5)
  • chemical defense  (4)
  • Ant predation  (1)
  • phenols
  • 1
    ISSN: 1423-0445
    Keywords: chemical defense ; insect repellent ; endangered species ; terpenes ; trans-pulegol ; Labiatae ; Dicerandra ; Pyralidae ; Pyrausta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Analyses of leaf extracts ofDicerandra frutescens, a highly aromatic mint plant from central Florida listed as an endangered species, revealed presence of 12 closely related monoterpenes. The principal of these, (+)—trans-pulegol, is a new natural product, the synthesis of which is described. The terpenes are produced in glandular capsules that release their contents upon injury of the leaf. Data from bioassays with ants and cockroaches indicate that the terpenes serve for defense against insects.Dicerandra does, however, have a leaf-eating enemy, the caterpillar of a pyralid moth,Pyrausta panopealis. The discovery of a new natural product from an endangered species raises questions about the chemical implications of species extinction.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1939
    Keywords: Ant predation ; Lepidopteran eggs ; Chemical defense ; Learned avoidance ; Automimicry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To examine the chemical defense of lepidopteran eggs towards ant predators, eggs of the arctiid moth Utetheisa ornatrix were offered to laboratory colonies of the ant Leptothorax longispinosus. The ants rapidly devoured Utetheisa eggs produced by parents reared on an alkaloid-free diet, but left eggs that had been endowed with parental alkaloid largely unmolested. That defense can be attributed directly to the presence of a pyrrolizidine alkaloid since topical application of monocrotaline in either its free base or N-oxide state conferred protection on otherwise palatable eggs. The N-oxide and free base were not equally effective in conferring protection however; free-base treated eggs were subject to greater predation than N-oxide treated eggs after 24 h. The emergence of differential alkaloid effectiveness only after prolonged exposure is consistent with the notion that chemical protection is seldom absolute. That difference was resolved only when the otherwise food-deprived ants exceeded a certain threshold of hunger. The efficacy of applied monocrotaline as a predator deterrent increased with increasing concentration of N-oxide, but was lowest for eggs treated with an intermediate concentration of free base. The latter concentration effect likely represents an artefact of the behaviour of the ant colonies offered eggs treated with an intermediate concentration, as those colonies were the most voracious predators in reference tests with palatable eggs. In addition to the immediate deterrent value of pyrrolizidine alkaloid, ant colonies that had been exposed to alkaloid-laden eggs subsequently avoided even palatable, unprotected eggs offered 33 days later. Our data provide the first demonstration of such long-term avoidance of chemically protected lepidopteran prey by an invertebrate. The discovery of a mechanism promoting learned avoidance on the part of ant predators has important ramifications to egg-laying strategies of female Utetheisa, both in terms of the dispersion of eggs, and the extent to which eggs are provisioned with alkaloid.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 16 (1990), S. 2823-2834 
    ISSN: 1573-1561
    Keywords: Diploptera punctata ; Orthoptera ; Blaberidae ; cockroach ; benzoquinone ; quinone ; chemical defense
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Diploptera punctata, a Pacific islands cockroach, discharges a fine aerosol ofp-benzoquinones from a pair of tracheal glands in response to disturbance or CO2 anesthesia. In addition, the glands and their contents are shed at each molt. We measured the amount ofp-benzoquinones discharged in response to pinching and anesthesia and the filling of glands after discharge and molting. Roaches discharge highly variable amounts of quinones but appear to retain approximately 11% of their lifetime total benzoquinone content after repeated discharges. Roaches rapidly fill their glands after molting (18Μg quinone/day) but after discharging appear to refill at a much slower rate or not at all. This lack of refilling could result from an inability to produce quinones after a finite time period or in excess of a fixed quantity. The delayed accumulation ofp-benzoquinone with respect to the alkylated derivatives in newly molted adults suggests competition for aromatic amino acids between cuticular and defensive quinone synthesis.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 20 (1994), S. 2743-2749 
    ISSN: 1573-1561
    Keywords: Hymenoptera ; Symphyta ; Tenthredinidae ; predation ; chemical defense ; ants ; Formicidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Evidence is presented from predation tests with ants (Formica exsectoides) that the slimy coating ofCaliroa cerasi and the waxy investiture ofEriocampa ovata serve in defense.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-1561
    Keywords: Entomopathogenic fungi ; insect egg ; Utetheisa ornatrix ; Lepidoptera ; Arctiidae ; chemical defense ; pyrrolizidine alkaloid ; monocrotaline ; parental investment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Eggs ofUtetheisa ornatrix proved equally vulnerable to fungal infection (Beauveria bassiana, Paecilomyces lilacinus) whether they contained parentally provided pyrrolizidine alkaloid (monocrotaline) or were free of such alkaloid. In in vitro tests, monocrotaline, either as free base or N-oxide, had no inhibiting effect on fungal cultures.
    Type of Medium: Electronic Resource
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