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41.
Jessica L. Adams Kari W. Camelio Matthew J. Orique Daniel T. Blumstein 《Behavioral ecology and sociobiology》2006,60(5):742-747
Antipredator behavior includes several qualitatively distinct activities, but few studies have determined the degree to which these activities are independent. If behaviors are not independent, then the nature of the relationship would illustrate potential performance constraints. We studied crimson rosellas (Platycercus elegans) and first focused on acoustic predator discrimination. We measured time allocation before and after playback of one of three experimental treatments (peregrine falcons—Falco peregrinus, wedge-tailed eagles—Aquila audax, and crimson rosellas) to determine whether or not rosellas discriminated predators from non-predators, and specifically whether or not they discriminated large from small predators. We then focused on the decision to flee. We experimentally approached subjects and measured the distance at which they oriented to us (alert distance) and the distance at which they fled (flight initiation distance; FID). We found that rosellas could distinguish among predators; however, there was no effect on general wariness as measured by FID. These two processes of antipredator behavior may, thus, be independent. 相似文献
42.
Social animals often use vocal communication signals that contain individual signatures. As bats emit echolocation calls several
times per second to orient in space, these might seem ideal candidates for conveying the caller's individual identity as a
free by-product. From a proximate perspective, however, coding of caller identity is hampered by the simple acoustic structure
of echolocation signals, by their task-specific design and by propagation loss. We investigated the occurrence of individual
signatures in echolocation calls in individually marked, free-living Bechstein's bats (Myotis bechsteinii) in a situation with defined social context in the field. The bats belonged to two different colonies, for both of which
genetic data on relatedness structure was available. While our data clearly demonstrate situation specificity of call structure,
the evidence for individual-specific signatures was relatively weak. We could not identify a robust and simple parameter that
would convey the caller's identity despite the situation-specific call variability. Discriminant function analysis assigned
calls to call sequences with good performance, but worsened drastically when tested with other sequences from the same bats.
Therefore, we caution against concluding from a satisfactory discrimination performance with identical training and test sequences
that individual bats can reliably be told apart by echolocation calls. At least the information contained in a single call
sequence seems not to be sufficient for that purpose. Starting frequencies did give the best discrimination between individuals,
and it was also this parameter that was correlated with genetic relatedness in one of our two study colonies. Echolocation
calls could serve as an additional source of information for individual recognition in Bechstein's bats societies, while it
is unlikely that a large number of individuals could be reliably identified in different situations based on echolocation
alone. 相似文献
43.
Chemical-mediated effects of predatory fish on chironomid larvae behaviour have been ignored so far. Sediment-dwelling chironomid larvae inhabit protective burrows from which they extend their bodies only to feed on deposited detritus and microalgae from the surrounding sediment. Here, we performed factorial laboratory experiments to study whether fish-borne chemical cues (kairomones) are responsible for behavioural trait changes of chironomid larvae, and whether chironomid larvae are able to assess the densities of fish predators and food resources and the trade-off between them. We exposed naïve Chironomus riparius larvae to the chemical presence of zero, one, and ten predator fish (Rutilus rutilus) and offered two resource levels (low food, high food) for each treatment. Kairomones induced significant inherent behavioural trait changes in chironomid larvae. During the first 120 min after exposing chironomids to fish-conditioned water, we found a significant increase in digging activity with increasing predator density. After 3 days of exposure, the deepest chironomid burrows were found in treatments with the highest predator density. Chironomid larvae were significantly able to adjust their foraging behaviour to different predator densities and food concentrations and trade off between them; that is, when fish predators were more abundant or when more food resources were available, the foraging activities of larvae were significantly reduced. Our data suggest that chemically mediated trait changes (burrowing and foraging behaviour) may cascade through the littoral food web. 相似文献
44.
Peter Schausberger 《Behavioral ecology and sociobiology》2005,58(1):53-59
A crucial question with respect to imprinting is how animals ensure that kin imprint on kin but not on non-kin. Imprinting takes place in a sensitive ontogenetic phase, usually in an early period of life or when offspring are produced, at which time the recipient imprints on the first referents met. In the predatory mite Phytoseiulus persimilis, imprinting among immature individuals happens in the larval stage immediately after hatching. I tested the hypothesis that adult P. persimilis females manipulate offspring imprinting by influencing the likelihood of encounters among recipients and referents via egg placement and egg aggregation. I conducted two experiments, one of which addressed imprinting and cannibalism, and the other addressed egg placement and egg aggregation. The imprinting experiment suggests that larvae imprint on any conspecific individual met in a sensitive ontogenetic phase and later on treat this individual as kin, irrespective of relatedness. After molting to protonymphs, imprinted individuals preferentially cannibalized unfamiliar to familiar larvae. Irrespective of familiarity, kin were cannibalized earlier than non-kin, suggesting the involvement of self-referent phenotype matching. The egg-placement experiment provides evidence that females adjust the aggregation level of their own eggs according to the degree of relatedness to present eggs from a previously ovipositing female. Both experiments in concert suggest that egg placement is a maternal strategy influencing imprinting among immature individuals. Apart from avoiding kin cannibalism, egg placement and imprinting by larvae may have relevance to other behaviors influenced by kin recognition, such as mate choice, prey-patch choice and dispersal.Communicated by L. Simmons 相似文献
45.
Summary. In amphibians and fishes, evidence is increasing that chemical cues from injured conspecifics can play a role in the chemical
labelling and learned recognition of unfamiliar predators. In this laboratory study, we tested the prediction that prior chemical
exposure to a non-native predator feeding on conspecific tadpoles will subsequently allow tadpoles of the common toad (Bufo bufo) to recognize the chemical cues specifically released by this starved predator. Furthermore, we investigated the vulnerability
of this chemically-mediated process to herbicide contamination. With these aims in view, groups of tadpoles were kept either
unexposed or exposed for ten days to chemical cues from Turkish crayfish (Astacus leptodactylus) previously fed on tadpoles, both in uncontaminated water and in the presence of four sublethal concentrations of amitrole
(0.01, 0.1, 1 and 10 mg.l−1). We then assessed the effects of the six conditioning treatments on general activity and behavioural response to chemical
cues from starved crayfish. Larval treatments did not affect the general activity of the tadpoles. By contrast, the treatments
had significant effects on the behavioural response to the test solution prepared form starved crayfish. The only tadpoles
to show an antipredator behavioural response to the chemical stimulation from starved crayfish belonged to the groups derived
from chemical exposure to tadpole-fed crayfish in uncontaminated water and in contaminated water with the lowest concentration
of amitrole (0.01 mg.l−1). Conversely, this chemical stimulation produced no behavioural change in the control group or in the groups derived from
exposure to tadpole-fed crayfish in contaminated water containing 0.1, 1 and 10 mg.l−1 of amitrole. This study demonstrates that chemical cues released during the predator’s feeding activity can subsequently
be used by common toad tadpoles in the recognition of an unfamiliar predator. In addition, our results show that the presence
of sublethal amitrole concentrations can impair this recognition process. Such a pesticide effect might be especially detrimental
for amphibian populations threatened by invasive predators. 相似文献
46.
Neighbour recognition allows territory owners to modulate their territorial response according to the threat posed by each
neighbour and thus to reduce the costs associated with territorial defence. Individual acoustic recognition of neighbours
has been shown in numerous bird species, but few of them had a large repertoire. Here, we tested individual vocal recognition
in a songbird with a large repertoire, the skylark Alauda arvensis. We first examined the physical basis for recognition in the song, and we then experimentally tested recognition by playing
back songs of adjacent neighbours and strangers. Males showed a lower territorial response to adjacent neighbours than to
strangers when we broadcast songs from the shared boundary. However, when we broadcast songs from the opposite boundary, males
showed a similar response to neighbours and strangers, indicating a spatial categorisation of adjacent neighbours’ songs.
Acoustic analyses revealed that males could potentially use the syntactical arrangement of syllables in sequences to identify
the songs of their neighbours. Neighbour interactions in skylarks are thus subtle relationships that can be modulated according
to the spatial position of each neighbour. 相似文献
47.
为防止煤矿工人吸入过量粉尘而导致职业性尘肺病,基于Keras框架利用YOLOv4 (you only look once)目标检测算法对井下人员佩戴防尘口罩情况进行高精度且快速的检测与识别,并与MTCNN(Multi-task convolutional neural network)和FaceNet构成的人脸识别算法相结合,进行煤矿工人口罩佩戴监测的研究。结果表明:模型对井下人员口罩佩戴有较高的检测精度,识别已佩戴口罩的矿井下作业人员的平均精度达到92.78%,识别未佩戴防尘口罩检测的平均精度为91.63%,与其他主流算法相比算法具有更好的鲁棒性和检测效果。研究结果为预防煤矿工人职业性尘肺病提供1种有效的技术手段。 相似文献
48.
Grzegorz Owczarek Grzegorz Gralewicz Natalia Skuza Piotr Jurowski 《International journal of occupational safety and ergonomics》2016,22(1):66-70
In this research the factors used to evaluate the light transmission through two types of acrylic hydrophobic intraocular lenses, one that contained yellow chromophore that blocks blue light transmission and the other which did not contain that filter, were defined according to various light condition, e.g., daylight and at night. The potential influence of light transmission trough intraocular lenses with or without yellow chromophore on functional vision in everyday environmental conditions was analysed. 相似文献
49.
50.