No abstract

Analyses of solvent rinses of the external surfaces of pheromone glands excised from calling female tobacco hornworm moths, Manduca sexta (L.), revealed the presence of the following compounds: (Z)‐9‐hexadecenal, (Z)‐11‐hexadecenal, (E)‐11‐hexadecenal, hexadecanal, (E,Z)‐10,12‐hexadecadienal, (E,E)‐10,12‐hexadecadienal, (E,E,Z)‐10,12,14‐hexadecatrienal, (E,E,E,)‐10,12,14‐hexadecatrienal, (Z)‐11‐octadecenal, (Z)‐13‐octadecenal, octadecanal, and (Z,Z)‐11,13‐octadecadienal. The two trienals were identified by mass and PMR spectral analyses and by ozonolyses, and their structures were confirmed by synthesis. In a wind tunnel male tobacco hornworm moths exhibit the same behaviors in response to a synthetic blend of all of the components, the gland rinse, or a calling female. Both (E,Z)‐10,12‐hexadecadienal and (E,E,Z)‐10,12,14‐hexadecatrienal are required to stimulate males to complete the characteristic behavioral sequence: anemotaxis, approaching and touching the pheromone source, and bending their abdomens in apparent copulatory attempts. The other components of the blend may play more subtle roles.

SUMMARYIn colonies of the olive fruit fly Dacus oleae maintained on an artificial substrate, an allele of the ADH locus whose frequency in natural populations is about 1 per cent increases in frequency to about 40 per cent within 6 generations of artificial rearing; the allele most common in natural populations suffers a compensatory decrease from 65 per cent to 30 per cent; a third allele is only slightly affected. This rapid genetic change coincides with an initial negative population growth rate followed by gradually increasing rates, an indication that the selection associated with this change has a toll on the colony's growth. Estimation of relative fitnesses shows that under artificial rearing, heterozygotes are on avera twenty times as fit as homozygotes. These are probably the largest selection differentials reported for allozymes, and are comparable only to differentials for tolerance to heavy metals in plants. The hypothesis of linkages of the ADH alleles with other genetic elements (e.g., chromosomal inversions), which are the targets of selection, cannot be excluded. The study demonstrates the types of selection pressures that may operate on newly established colonies of "domesticated" insects and the genetic changes that may result from them.

The virulence of two isolates of the hyphomycete fungi, Beauveria bassiana and B. brongniartii, and additional fungal species isolated from diseased Bactrocera oleae pupae and Sesamia nonagrioides larvae were assessed against adults of the olive fruit fly B. oleae and the Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae). Contact and oral bioassays revealed that moderate to high mortality rates for the olive fruit fly occurred when the adults were exposed to conidia of Mucor hiemalis, Penicillium aurantiogriseum, P. chrysogenum and B. bassiana isolates. A strain of M. hiemalis isolated from S. nonagrioides larvae was the most toxic resulting in 85.2% mortality to the olive fruit fly adults. B. brongniartii and B. bassiana were the most pathogenic to the C. capitata adults causing 97.4 and 85.6% mortality. Metabolites collected from the M. hiemalis and P. chrysogenum isolates were toxic to adults of both species.

Male olive fruit fly attraction to the four synthetic components of the female sex attractant pheromone was studied under laboratory and field conditions. In laboratory tests males responded to all four components tested separately. Component I, (1,7-dioxaspiro[5.5]undecane) was more attractive than any of the remaining three components alone, but a combination of all four was more attractive than component I alone. In field tests with polyethylene vials as pheromone dispensers, the complete mixture, although not statistically significant, was constantly more attractive to males than component I alone. A tendency of enhancement of attraction of component I by combining it with component II (α-pinene) or III (n-nonanal) was also observed. In field tests with rubber septa as pheromone dispensers only component I was attractive. Mixtures containing component I were also attractive but not more attractive than component I alone. Evaporation rate and ratio of components as they come out of the dispenser appear to be critical for male response.

No abstract

Field studies were conducted to evaluate the influence of trap design, trapping location, type of pheromone dispenser, and trap color on the capture of Palpita unionalis (Hübner) males, in olive groves. The experiments were carried out in two regions, Alexandria (northern Greece) and Oropos (central Greece), where olives are cultivated. In both regions, the majority of the males (> 70% of the total) were caught from late autumn to early winter, whereas < 1% was caught during July and August. Among the trap types used, the Funnel was significantly more attractive than Delta, Pherocon 1C, and Pherocon II traps. More males were caught in traps placed at the periphery of the groves than those placed in the center. Among the four colored traps tested, white traps were the most effective. However, a significant difference in trap catches was found between white and brown traps. Traps baited with red rubber septa captured more males than those baited with the white one. The use of these parameters in monitoring and managing P. unionalis is discussed.

The sex attractant pheromone produced by femaleDacus oleae Gmelin is a mixture of four compounds, two of which are found in the rectal gland and the other two elsewhere in the insect body. The ratio of these compounds in the pheromone blend was measured. Biological activity of all four compounds and their combinations was studied in lab and field cage tests. The most abundant compound in the mixture (55.7%) shows the highest biological activity. Recombination of all compounds significantly increases activity of the main compound.