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- Löfstedt, Christer, et al.
(författare)
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Behavioral responses of male turnip moths, Agrotis segetum, to sex pheromone in a flight tunnel and in the field
- 1985
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 11:9, s. 1209-1221
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Tidskriftsartikel (refereegranskat)abstract
- The response of individual male turnip moths Agrotis segetum was observed in a sustained flight tunnel to a mixture of decyl acetate, (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate in proportions similar to those found in gland extracts from virgin females (0.6: 1:5:2.5). Lures containing 3-30 μg (Z)-5-decenyl acetate proved to be maximally attractive, with approximately 60% of the males completing all behavioral steps from activation to copulation efforts. A 300-μg dosage caused significant arrestment of upwind flight. Peak response to synthetics, however, was significantly lower than to female glands. Omitting decyl acetate from the blend did not affect the activity, while omission of any of the three monounsaturated acetates caused a dramatic decrease in response. In the field maximum trap catches were achieved with 1- to 30-μg lures. The subtractive assay carried out in the field confirmed the neutrality of decyl acetate and the importance of the three monoenes. Adding 1% of (Z)-8-dodecenyl acetate (earlier reported as an "inhibitor") to the four-component mixture decreased the trap catch to about 50%, and increasing the amount of (Z)-8-dodecenyl acetate to 27% decreased the activity further to about 10%. (Z)-8-Dodecenyl acetate also decreased the number of successful flights in the flight tunnel.
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| 3. |
- Mossing, Torgny
(författare)
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Seasonal variations in general activity, behaviour and cutaneous glandular structures in reindeer (Rangifer tarandus L.)
- 1980
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The locomotor activity of the reindeer is separated into a diurnal and a nocturnal phase which, in turn, consists of a number of short-term activity bursts. The onset and termination of diurnal and nocturnal activity are largely in synchrony with sunrise and sunset. Since the diurnal phase is longer, total activity is dependent on the photoperiod. Total activity as well as the number of activity bursts is greater in Jùne with continuous daylight than in December with 6 hours daylight. In winter, reindeer spent less time feeding but more time ruminating and resting *than in summer. Synchronization between individuals was also greatest in winter. It is concluded that the described changes in the activity pattern are due to an endogenous component and that this component further controls food consumption and energy balance of the reindeer. Seasonal variations in behavioural patterns are described. Several specific rutting behavioürs, sexual and agonostic, emerge in the male during the prerut and persist until after the rut. The preorbital gland is enlarged and secretory activity is evident. The rut is cha'tabterized by the sudden appearance of an odour in the breath of mature males followed a few later by a strong odour in the urine. These odours persist for a short time during the most intense period of rut. The amount of androgen rizes sharply and reaches peak concentrations in late September - early October, decreasing thereafter. The described behavioural cues occur with a certain constancy in time in concecutive seasons. A quantification of the amounts of secretory epithelia in preorbital, interdigital, caudal and tarsal glands reveals that only the preorbital gland is subjected to any seasonal and sexual variation. The apocrine epithelium in this gland is most developed in mature males during the rutting season and seems to be dependent upon the presence of an elevated androgen concentration. The tarsal gland is the least developed gland while the interdigital and caudal glands are more welldeveloped and structurally complex. Scattered apocrine glands are only developed on the legs, the ventral body, oral angle and in the rump patch.
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| 4. |
- Baker, Thomas C., et al.
(författare)
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Adaptation of antennal neurons in moths is associated with cessation of pheromone-mediated upwind flight
- 1988
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 85:24, s. 9826-9830
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Tidskriftsartikel (refereegranskat)abstract
- A wind-borne plume of sex pheromone from a female moth or a synthetic source has a fine, filamentous structure that creates steep and rapid fluctuations in concentration from a male moth flying up the plume's axis. The firing rates from single antennal neurons on Agrotis segetum antennae decreased to nearly zero within seconds after the antennae were placed in a pheromone plume 70 cm downwind of a high-concentration source known from previous studies to cause in-flight arrestment of upwind progress. In a separate experiment, the fluctuating output from chilled neurons on Grapholita molesta antennae became attenuated in response to repetitive, experimentally delivered pheromone pulses. The attenuation was correlated with a previously reported higher percentage of in-flight arrestment exhibited by moths flying at cooler compared to warmer temperatures. These results indicate that two peripheral processes related to excessive concentration, complete adaptation of antennal neurons, or merely the attenuation of fluctuations in burst frequency, are important determinants of when upwind progress by a moth flying in a pheromone plume stops and changes to station keeping. Also, adaptation and attenuation may affect the sensation of blend quality by preferentially affecting cells sensitive to the most abundant components in airborne pheromone blends.
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| 5. |
- Baker, Thomas C., et al.
(författare)
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Adaptation of male moth antennal neurons in a pheromone plume is associated with cessation of pheromone-mediated flight
- 1989
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 14:3, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- Recordings of the firing rates of single antennal neurons when Agrotis segetum antennac were placed 70 cm downwind of a pheromone source revealed that cells sensitive to the most volatile component adapted rapidly in a plume from a high-concentration source known from previous studies to cause in-flight arrestment of progress towards the source. No adaptation was found in response to lower-concentration plumes known to promote high levels of sustained flight to the source with little premature arrestment. Adaptation was not observed in antennal neurons of a second species, Heliothis virescens, when they were placed in plumes of this species' sex pheromone blend, regardless of the concentration. In flight-tunnel tests these same pheromone sources evoked high levels of source location with little arrestment. These results indicate that adaptation or attenuation of antennal neuronal burst frequencies in response to rapidly arriving pheromone filaments in a plume may be important peripheral determinants of whether or not prolonged upwind flight and successful pheromone source location occurs.
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| 6. |
- Bengtsson, Hans, et al.
(författare)
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Parental feeding rate in relation to begging behavior in asynchronously hatched broods of the great tit Parus major: An experimental study.
- 1983
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Ingår i: Behavioral Ecology and Sociobiology. - 1432-0762. ; 12:3, s. 243-251
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Tidskriftsartikel (refereegranskat)abstract
- Four experiments manipulated the stimulus situation encountered by great tits on their feeding visits to the brood in order to explore its effect on feeding rate. Three broods containing 8, 8, and 10 nestlings were studied. A higher feeding rate was observed under the following conditions: (1) after a period of food deprivation, as compared with normal conditions and satiation through artifical feeding; (2) in periods when recorded begging calls were played during feeding visits, as compared with control periods; and (3) after temporary removal from the nest of heavier, as compared with lighter, siblings. The lighter nestlings benefitted more (in terms of weight gain) from the increase in parental feeding rate following the playing of begging calls than did the heavier nestlings. Differences in weight within broods did not affect the amount of food the parents brought. It is concluded that parental feeding rate is affected not simply by the begging of the hungriest nestling but rather by the behavior of all the nestlings, which makes possible an adjustment of the feeding rate to the average hunger level of the brood.
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