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| 3. |
- Anderbrant, O., et al.
(författare)
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Diprionyl esters attractive to males of the dailing pine sawfly Neodiprion dailingensis Xiao et Zhou (Hym., Diprionidae) in north-eastern China
- 1997
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Ingår i: Journal of Applied Entomology. - 0931-2048. ; 121:5, s. 281-283
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Tidskriftsartikel (refereegranskat)abstract
- The attraction of male Neodiprion dailingensis Xiao et Zhou to pheromone substances identified from other Neodiprion species was tested in plantations of Pinus tabulaeformis Carr. in Liaoning Province in north-eastern China. Both the acetate and propionate of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) were highly attractive. An addition of 10% of the (2S,3R,7R)-isomer did not significantly reduce the catch to the acetate. The (2S,3R,7R)-isomer was not attractive by itself. This is the first pheromone study of a species belonging to the recently described East Asian group of Neodiprion. The response of N. dailingensis males is similar to that of N. sertifer males in eastern part of Asia.
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| 4. |
- Anderbrant, Olle, et al.
(författare)
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Field response of the pine sawfly Neodiprion sertifer to controlled release of diprionyl acetate, diprionyl propionate and trans-perillenal
- 1992
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 18:10, s. 1707-1725
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Tidskriftsartikel (refereegranskat)abstract
- Two dispenser types for pine sawfly (Hymenoptera: Diprionidae) pheromones-glass capillaries and dental cotton rolls-are described, and release rates reported. Glass capillaries of different diameters were used in field tests to determine dose-response relationships of (2 S,3 S,7 S)-3,7-dimethylpentadecan-2-yl acetate (diprionyl acetate), diprionyl propionate, and trans-perillenal on the trap catch of male Neodiprion sertifer. A linear relationship between the logarithm of the capillary cross-sectional area and the logarithm of the release rate was found. However, capillaries of the same diameter could vary in the amount released by as much as a factor of 10. Both the acetate and propionate were attractive alone, but no synergistic effect was found. trans-Perillenal did not show any behavioral activity. Dental cotton rolls have been used extensively in diprionid pheromone research without knowledge about release rates. The release rate from rolls loaded with different amounts of diprionyl acetate was determined by extracting rolls after different times under constant temperature and wind conditions or after use in field tests. Quantification of diprionyl acetate was done on GC. The release rate was found to be proportional to the amount applied over several orders of magnitude, and persisted for several weeks. Capillaries and rolls with similar release rates caught similar numbers of sawflies.
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- Löfstedt, Christer, et al.
(författare)
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Behavioural and electrophysiological activity of unsaturated analogues of the pheromone tetradecyl acetate in the small ermine moth Yponomeuta rorellus
- 1990
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Ingår i: Physiological Entomology. - : Wiley. - 0307-6962 .- 1365-3032. ; 15:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT In field‐trapping experiments the unsaturated analogues (E)‐6‐, (E)‐12‐, and (Z)‐12‐tetradecenyl acetate were as attractive to male Yponomeuta rorellus Latr. as the native pheromone component tetradecyl acetate. All four analogues attracted more males than virgin females did, whereas (Z)‐6‐, (E)‐11‐, (Z)‐10‐ and (Z)‐11‐tetradecenyl acetate were essentially non‐attractive. Addition of 1–30% of (Z)‐11‐tetradecenyl acetate to the pheromone tetradecyl acetate reduced the attraction to less than 2%. Flight tunnel experiments with Y. rorellus confirmed the activity of the (E)‐6‐ and (E)‐12‐tetradecenyl acetates and demonstrated the activity of (E)‐7‐tetradecenyl acetate as well. These analogues elicited orientation behaviour, upwind flight and landing at the odour source as frequently as the native pheromone did. Single sensillum recordings from male Y. rorellus showed two types of cells in most sensilla. A large spike amplitude cell was stimulated by tetradecyl acetate and the unsaturated analogues (E)‐11‐, (E)‐6‐ and (E)‐12‐tetradecenyl acetate, and to a lower extent by the (Z)‐6‐, (Z)‐11‐ and (Z)‐12‐isomers. A cell with medium spike amplitude was stimulated by (Z)‐9‐tetradecenyl and (Z)‐11‐hexadecenyl acetate. Some sensilla contained a third cell firing with a small spike amplitude which was activated by (Z)‐11‐tetradecenol. Thus the tetradecyl acetate receptor was stimulated not only by the behaviourally active analogues, but also by behavioural antagonists. The interaction of (E)‐11‐tetra‐decenyl acetate and tetradecyl acetate with the same antennal receptor cell was also demonstrated in Y.cagnagellus. Electrophysiological discrimination between behavioural attractants and antagonists and the role of behavioural antagonists in the interspecific relations between Y.rorellus and sympatric closely related species are discussed.
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- Svensson, Erik, et al.
(författare)
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The trade-off between molt andparental care: a sexual conflict in the blue tit?
- 1997
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 8:1, s. 92-98
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Tidskriftsartikel (refereegranskat)abstract
- Breeding activities and molt are generally thought to be mutually exclusive in birds since both are energetically costly and are normally separated in time. However, sometimes molt overlaps with breeding to some degree. A trade-off between adult somatic maintenance functions (feather renewal) and parental care is then to be expected. The consequences of this are largely unknown, and there are few studies that have shown any fitness costs of molt-breeding overlap. We investigated the consequences of molt-breeding overlap by removing first clutches of blue tit Parus caeruleus pairs, thereby inducing late repeat clutches. Among the delayed pairs, a high proportion of males and some females started their molt already during incubation or nestling feeding. Molting males fed their nestling to a lesser extent than non-molting ones, and nestling mortality increased as a direct result of the early timing of male molt. Furthermore, the ability to raise an experimentally enlarged brood was negatively coupled to the molt stage of the male. Our data thus protide evidence that molt-breeding overlap leads to fitness costs, and we discuss the results within the context of sexual conflict and the implications for optimization of avian reproductive decisions.
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| 7. |
- Vincent, Amanda, et al.
(författare)
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Operational sex ratios and behavioral sex differences in a pipefish population
- 1994
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Ingår i: Behavioral Ecology and Sociobiology. - 0340-5443 .- 1432-0762. ; 34, s. 435-442
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Tidskriftsartikel (refereegranskat)abstract
- In the pipefish Syngnathus typhle, only males brood embryos in specially developed brood pouches, supplying oxygen and nutrients. Laboratory studies have shown that this elaborate paternal care has led to sex-role reversal in this species: males limit female reproductive rate, females are the primary competitors for mates and males exercise greater selectivity in accepting mates. In the first field study of this pipefish, we describe mating behaviour in the wild and test the hypothesis that temporal variations in the operational sex ratio (OSR) determine sex differences in mating behaviour. Our study comprised two reproductive seasons of two sequential mating periods each, the latter separated by a lengthy interval of male brooding. During mating periods, females displayed to all males without wandering and males moved about searching for females, without reacting to all females. The OSR was least female-biased (or even male-biased) at the onset of the breeding season, when most pipefish were simultaneously available to mate, but became strikingly female-biased as males' pouches were filled. The OSR remained substantially female-biased during the second mating period, because few males became available to remate at any one time. As hypothesised, female-biased OSRs resulted in more female-female meetings. As well, females were above the eelgrass more often than brooding males, thus exposing themselves to conspecifics and/or predators. In the second year, males arrived earlier than females on the breeding site and male pregnancies were shorter, because of higher water temperatures, so rematings occurred earlier. Males met more often during that year than the previous one, but male competitive interactions were still not observed. The field results support laboratory studies and demonstrate that behaviours associated with female-female competition are more prominent when the OSR is more female-biased.
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| 8. |
- Anderbrant, O., et al.
(författare)
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Electrophysiological and morphological characteristics of pheromone receptors in male pine sawflies, Diprion pini (Hymenoptera : Diprionidae), and behavioural response to some compounds
- 1995
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Ingår i: Journal of Insect Physiology. - : Elsevier BV. - 0022-1910. ; 41:5, s. 395-401
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Tidskriftsartikel (refereegranskat)abstract
- The morphology and physiology of pheromone receptors on the antennae of male pine sawflies, Diprion pini L., were investigated. Using scanning electron microscopy, five sensillar types were recognized. The type shown to be pheromone sensitive has a long (50-70 μm) cuticular hair, is single-walled, and is innervated by 8 or 9 sensory cells as revealed by transmission electron microscopy. Electroantennography (EAG) showed similar activity of the acetate and propionate of (2S,3R,7R)-3,7-dimethyl-2-tridecanol, precursor of the main constituent of the female-produced sex pheromone. No other isomer induced any significant response. Single-sensillum recordings confirmed the results of the EAG, and also showed that several neurons were excited by the active compound. EAG recordings and combined gas chromatographic-electroantennographic detection indicated that esters of three 3,7-dimethyl-2-pentadecanol (diprionol) isomers were active, but field tests could not demonstrate any behavioural effect. Diprionol esters are used as sex pheromones by all other pine sawflies investigated so far, and D. pini is thus the first diprionid species shown to use a different sex pheromone.
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| 9. |
- Anderbrant, Olle
(författare)
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Gallery construction and oviposition of the bark beetle Ips typographus (Coleoptera : Scolytidae) at different breeding densities
- 1990
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 15:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Abstract. 1. The bole of a Norway spruce, Picea abies(L.) Karst., was cut in 25 cm sections and infested in the laboratory with 2 or 8 females/dm2 of Ips typographus (L.) and an equal number of males. 2. One log of each beetle density was dissected every second day, beginning 2 days after female introduction. 3. The oviposition rate was highest at the beginning of the breeding period for both densities and then declined, especially at the high density. Residence time is a useful approximation for the number of laid eggs in the beginning of the oviposition period or when the density is low. 4. Final gallery length and egg number per gallery were on average significantly smaller at density 8 than at density 2. 5. Linear relationships between total gallery length and number of egg niches were found to be similar for the two densities. 6. An estimate of the egg to adult mortality at different densities was found by using data from a field study that related gallery length to breeding density in attacked living trees, together with published relationships between density and egg niches or emergence of new adults. 7. It was concluded that both decreased oviposition rate and earlier re‐emergence at higher densities contribute to a declining oviposition with increasing density. The final offspring production is futher reduced by lower survival due to larval competition as density increases.
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| 10. |
- Blümke, A., et al.
(författare)
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Oviposition pattern and behaviour of the pine sawfly Neodiprion sertifer (Hymenoptera Diprionidae)
- 1997
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Ingår i: Bulletin of Entomological Research. - 0007-4853. ; 87:3, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- The potential role of oviposition deterrents in the egglaying behaviour of Neodiprion sertifer (Geoffroy) females was studied by investigation of natural egg distribution, and by a laboratory study of potential oviposition deterrents. Pine shoots were sampled from different whorls on the sun-exposed and the shaded side of trees. More shoots with eggs from two or more females were found than would be expected if each female laid eggs on a randomly chosen shoot. The anti-predatory larval oral secretion of N. sertifer had no effect on N. sertifer egglaying but acted as an oviposition deterrent to Diprion pini in laboratory experiments. The different responses may be due to differences in the species' life-cycles. In other experiments, the effect of the presence of N. sertifer eggs, extracts obtained from eggs or from needles with eggs, were all tested on N. sertifer egglaying. None of the treatments had any inhibitory effect on egglaying. Thus, neither the natural pattern of egg distribution nor the results of the laboratory experiments indicated that an oviposition deterring pheromone is used by N. sertifer. Results from earlier studies, showing a deterrent effect of larval oral secretion in D. pini, were confirmed.
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