Jan Nawrot

Sex-dependent composition of cuticular hydrocarbons of the colorado beetle, Leptinotarsa decemlineata say

Abstract 1. 1. Qualitative and quantitative investigation of epicuticular and internal hydrocarbons of Colorado beetles of winter generation were performed. 2. 2. Quantitative compositional differences for sexes were found. 3. 3. Females contain more branched methylalkanes whose tentative structure was identified as either tetramethylhentriacontane or trimethyltritriacontane or a mixture of both. 4. 4. Compositional studies of potato leaves were also done. A prominent component of leaf waxes, 2-methyltricontane, was also found in cuticular hydrocarbons of both sexes as one of the most abundant compounds.

Cuticular hydrocarbons of the german cockroach, Blattella germanica L.

1. 1. The cuticular hydrocarbons from the German cockroach consist of n-alkanes, 3-methylalkanes, internally branched monomethylalkanes and dimethylalkanes. 2. 2. The composition of the hydrocarbon fraction differs markedly from the other species of cockroaches. n-Nonacosane and n-heptacosane as well as their monomethyl and dimethylderivatives are the major constituents of the hydrocarbon fraction from Blattella germanica. 3. 3. Lesser amounts of n-octacosane and two of its monomethylisomers have also been identified. 4. 4. The dimethylalkanes are nearly all 3,X-dimethylalkanes. There are 3, 5 and 7 methylene groups between the 3 and X in the various chains from carbon numbers 27–29.

Feeding-deterrent activity of α-asarone isomers against some stored Coleoptera

All isomers of α-asarone [(E)-4-prop-1-enyl-1,2,5-trimethoxybenzene] were tested for their feeding deterrent activity against adults of Sitophilus granarius and Tribolium confusum and larvae of Trogoderma granarium and Tribolium confusum. (E)-2-prop-1-enyl-1,3,5-trimethoxybenzene exhibited the strongest deterrent activity against all the species tested. The total coefficients of deterrency for this compound were 140.6 and 169.7 for Tribolium confusum adults and larvae, respectively, and 144.9 and 104.6 for larvae of Trogoderma granarium and adults of Sitophilus granarius, respectively. © 2000 Society of Chemical Industry

Leaf surface compounds of the potato (Solanum tuberosum) and their influence on Colorado potato beetle (Leptinotarsa decemlineata) feeding

Summary.The sampling behavior of the Colorado potato beetle Leptinotarsa decemlineata Say (CPB) involves examination of the surface of potato leaves. It has been suggested that leaf surface compounds (volatiles and cuticular waxes) may be involved in host-plant recognition, acceptance or discrimination. Here we report on the effect of leaf surface extracts of six Polish commercial potato varieties on CPB feeding. We tested the influence of potato leaf surface extracts on CPB adult and larval feeding, then separated the extracts with HPLC, and finally tested the effect of the HPLC-separated fractions on CPB feeding. The bioassays were performed using potato leaf discs deprived of their original surface compounds. Applied to test discs at concentrations ten times higher than natural (10 leaf area equivalent), the extracts deterred CPB adults and larvae from feeding. HPLC-separated fractions composed of alkanes, sesquiterpene hydrocarbons, wax esters, benzoic acid esters, fatty acid methyl, ethyl, isopropyl and phenylethyl esters, aldehydes, ketones, methyl ketones, fatty acids, primary alcohols, β-amyrin and sterols did not affect adult CPB feeding. Similarly, alkanes, sesquiterpene hydrocarbons, wax esters, methyl ketones, sesquiterpene alcohols and secondary alcohols had no effect on larval CPB feeding. The sterol fraction (cholesterol, β-sitosterol and stigmasterol) acted as a phagostimulant to CPB larvae. We isolated a fraction demonstrating a phagodeterrent effect on CPB adults and larvae. The qualitative composition of the deterrent fraction was quite similar in all potato extracts, but there were quantitative differences between the varieties. Much further work is needed to identify the compounds that can produce the deterrent effect.

The composition of cuticular hydrocarbons of the bean weevil, Acanthoscelides obtectus say

Abstract 1. 1. Hydrocarbons of the bean weevil, Acanthoscelides obtectus Say constitute 22 and 3.7% of outer and inner lipids of insects, respectively. 2. 2. There were n- alkanes , monomethylalkanes, dimethylalkanes and trimethylalkanes. The major components were 9,13-dimethylheptacosane, n- heptacosane , 3-methylheptacosane and 9- and 11-methylheptacosane. 3. 3. Qualitative similarities of these hydrocarbons and those of cowpea weevil, Callosobruchus maculatus were found.

The composition of hydrocarbons of the larvae of the khapra beetles Trogoderma granarium

Abstract 1. 1. The cuticular and internal hydrocarbons of the larvae of the khapra beetles Trogoderma granarium were studied by capillary column gas chromatography and mass spectrometry, n -Alkanes, 3-methyl-, 5-methyl-, 11-methyl-, 12-methyl-, 13-methyl-, 14-methyl- and 15-methylalkanes, Δ 11 -alkenes and Δ 10,14 nonacosadiene were found in cuticular and internal lipids. 2. 2. Significant quantitative differences of the compositions were estimated for cuticular and internal hydrocarbons. 3. 3. The n -alkanes found in the samples are mostly odd chain lengths from 27 to 33 carbon atoms. In turn, the branched hydrocarbons consist of even carbon numbers ranging from C 27 to C 34 , but the branching points are situated on the odd carbon numbers. 4. 4. The n -alkenes have exclusively odd carbon numbers ranging from 27 to 33.

The composition of cuticular hydrocarbons of the Tribolium destructor

Abstract 1. 1. The hydrocarbons from the Tribolium destructor consist of n -alkanes, 3-methylalkanes, internally branched alkanes (4-, 5-, 11- 12- and 13-methylalkanes), dimethylalkanes, pentadecen-1 and C 14 –C 17 alkadienes. 2. 2. The pentadecen-1 and alkadienes occur most probably in defense secretion as in the case of other species belonging to the tribe Tenebronidae. 3. 3. The other hydrocarbons ranging from C 25 to C 30 are cuticular. 4. 4. The composition of cuticular hydrocarbons is similar to those of Tribolium castaneum and Tribolium confusum . However, there are some qualitative sand quantitative differences.

The compositoin of cuticular hydrocarbons of the cereal aphids Sitobion avenae F. (Homoptera, Aphididae)

Abstract 1. 1. The cuticular hydrocarbons of the cereal aphids, Sitobion avenae F. were studyed by capillary column chromatography and mass spectrometry. 2. 2. n-Alkanes, 2-, 3-, 4-, 5-, 6-, 10-, 11-, 12- and 13-monomethylalkanes, 7,11-, 11,15-, 13,17- and 5,11-dimethylalkanes were found in cuticular lipids. 3. 3. The results obtained are significantly different from these of pea aphid, where only n-alkanes were found. 4. 4. The n-alkanes of cereal aphids range from 23 to 35 carbon atoms with the predominance of odd over even members. 5. 5. These are terminally branched hydrocarbons 2-methyl and 3-methyl-alkanes rarely found together in cuticular lipids of insects.

The composition of cuticular hydrocarbons of the khapra beetles, trogoderma granarium

Abstract 1. 1. The cuticular and internal hydrocarbons of the khapra beetle Trogoderma granarium were studied by capillary column gas chromatography and mass spectrometry. n -Alkanes, 3-methyl-, 5-methyl-, 11-methyl-, 12-methyl-, 13-methyl-, 14-methyl- and 15-methylalkanes were found in the cuticular and internal lipids. 2. 2. Some quantitative differences of the compositions were estimated for cuticular and internal hydrocarbons. 3. 3. The n -alkanes in the samples are mostly odd chain lengths from 23 to 33 carbon atoms. In turn, the branched hydrocarbons consist of even carbon numbers ranging from C 26 to C 32 , but the branching points are situated on the odd carbon numbers. 4. 4. There are similarities in the n -alkanes patterns extracted from khapra beetle and wheat grains, the latter of which are the natural nutrition of this pest.

Study of lipophilicity of alpha-asarone derivatives and their deterrent activity against the Colorado potato beetle

AbstractFive positional isomers and thirty derivatives of alpha-asarone wereobtained as a bioactive set of substances, and their deterrent activity against the Colorado potato beetle was studied. The lipophilicity values of thirty-six compounds were determined by using experimental, chromatographic and theoretical methods. The logkw values for all compounds were determined by reversed-phase high-performance liquid chromatography using five different columns. The octan-1-ol/water partition coefficients values were determined experimentally as a measure of lipophilicity. For the purpose of comparison, theoretical lipophilic parameters for all compounds were calculated with the use of chemical programs. The experimental, chromatographic and calculated values were compared using linear regression analysis. The most significant correlations were found between the chromatographic lipophilicities using methanol/water for all tested columns and calculated values. It has been found that 13 compounds have the lowest lipophilicities, which correspond to deterrent activity. The presented results show that the computational method is useful for determining the lipophilicity of a series of homologues, but not for positional isomers. In addition, this study shows that determination of lipophilicity using HPLC with various stationary phases is practical and reasonable for all alpha-asarone derivatives.