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71.
S. Fuchs 《Behavioral ecology and sociobiology》1976,1(2):155-184
1. | The physical characteristics of the drumming signal produced by workers of carpenter ants (Camponotus herculeanus L.) inside their nests, constructed in trees, were investigated. Typical elements of the inner nest structure are lamellae of about 50–500 cm2 derived from gnawing out the soft spring wood. On the thinnest lamellae (about 1 mm thick) the highest acceleration amplitudes of the signal were measured (on average 375 cm/s2 from peak to peak). The largest part of the intensity spectrum is between 200 and 1,500 Hz. On thicker lamellae the acceleration amplitudes are lower (at 12 mm thickness they average 140 cm/s2), and the upper end of the frequency range of the intensity spectrum is increased. The attenuation during the transmission is least along the longitudinal axis of thin cantilever lamellae (0.4 dB/cm) without alterations of thickness or connections to other lamellae. On a typical structure of the inner nest the attenuation is 1.2 dB/cm in the longitudinal axis, 2.7 dB/cm in the tangential axis and 4.3 dB/cm in the radial axis. |
2. | The frequency of behavioural reactions to some vibrational stimuli was investigated. In worker ants sine-wave pulses release a stop-reaction (total freezing) or several reactions combined with locomotion (run-reactions). At high intensities (500 cm/s2) and high frequencies (1,000 Hz) mostly run-reactions occur, whereas, at the lower ranges, the stop-reaction predominates. The stop-reaction is released more often if the rise-decay times of the sine-wave pulses are short. The lowest acceleration threshold of reactions is 5 cm/s2 at frequencies ranging between 250–750 Hz. Stimulation with shockpulses causes mostly the stop-reaction and only few run-reactions. The lowest threshold is 5 cm/s2. Thus the animals can perceive the drumming signal over an average distance, depending on the direction of transmission, of 10–30 cm, and over 90 cm at the maximum. Shockpulse series are a stronger stimulus than single pulses of the same acceleration amplitude. The most effective time interval of the shockpulses is about 50 ms, which is the most frequent time interval of the beats of the natural drumming. A simple model describes the increased effect of shockpulse series by an additive superposition of functions of residual effects following the single pulses. |
3. | Collective behavioural reactions to imitated drumming signals were investigated. They depend on the situation of the perceiving animals. The locomotory activity, measured by the number of changes from one nest compartment to the next, is increased by the signal. The combination with a second stimulus (air-puffs) increases the locomotory activity even more, and at the intensities used, multiplies the effects of the different stimuli. No orientation of the reactions with respect to the vibration source was found. The drumming signal shortens the time which males, females or larvae need to depart or to be carried by worker ants from nest areas affected by light to darkened ones. If ants of other species intrude into a nest, they are attacked more often. The drumming signal is not involved in the coordination of the mating flight. |
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Although mate guarding as prevention of extra-pair copulation is common among birds, evidence for aggressive behaviour involving
physical contact related to mate guarding in passerines is scarce and cases of the presence of one partner directly influencing
the aggressiveness of the other are lacking. We investigated the intra-specific territorial behaviour of male meadow pipits
(Anthus pratensis; Passeriformes: Motacillidae) at the beginning of the breeding season by placing a pipit model accompanied by an intra-specific
song playback in the territory of socially paired males and compared the responses of males whose mates were physically present
during trials with those whose females were out of sight. The level of aggression of males was significantly higher in the
presence of the female; half of the males in this group physically attacked the model (the most intense and risky aggressive
behaviour). Physical attacks did not occur among males whose female was absent during the trial; response to the playback
by most of these males was only weak. This pattern may be related to the prevention of extra-pair copulation; if the risks
involved in the conflict are outweighed by potential loss of paternity, such aggressive mate guarding may pay off. The apparently
overlooked effect on the territorial behaviour of a partner’s passive physical presence during conflict should be further
evaluated because it may be important for the design and interpretation of results of behavioural experiments. 相似文献
80.
Paul J. Mann Jens Strauss Juri Palmtag Kelsey Dowdy Olga Ogneva Matthias Fuchs Michael Bedington Ricardo Torres Luca Polimene Paul Overduin Gesine Mollenhauer Guido Grosse Volker Rachold William V. Sobczak Robert G. M. Spencer Bennet Juhls 《Ambio》2022,51(2):439
Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples'' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes may affect coastal processes, food web dynamics and marine resources on which many traditional ways of life rely. Here, we examine how future projected increases in runoff and permafrost thaw from two permafrost-dominated Siberian watersheds—the Kolyma and Lena, may alter carbon turnover rates and OC distributions through river networks. We demonstrate that the unique composition of terrestrial permafrost-derived OC can cause significant increases to aquatic carbon degradation rates (20 to 60% faster rates with 1% permafrost OC). We compile results on aquatic OC degradation and examine how strengthening Arctic hydrological cycles may increase the connectivity between terrestrial landscapes and receiving nearshore ecosystems, with potential ramifications for coastal carbon budgets and ecosystem structure. To address the future challenges Arctic coastal communities will face, we argue that it will become essential to consider how nearshore ecosystems will respond to changing coastal inputs and identify how these may affect the resiliency and availability of essential food resources.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01666-z. 相似文献