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191.
Gábor Herczeg Abigél Gonda Jarmo Saarikivi Juha Merilä 《Behavioral ecology and sociobiology》2006,60(3):405-414
According to Huey and Slatkin’s [Q Rev Biol 51:363–384, 1976] cost–benefit model of behavioural thermoregulation, lizards should adjust their thermoregulatory strategy between active thermoregulation and thermoconformity (no thermoregulation) according to the costs (time and energy spent thermoregulating, exposure to predators), benefits (optimised physiological performance) and thermal quality of environment associated with a given situation. However, Gilchrist’s [Am Nat 146:252–270, 1995] model of thermal specialisation suggests that apparently costly mechanisms of behavioural thermoregulation can greatly increase fitness if the optimal body temperature is achieved. Field studies of ectotherm thermoregulatory strategies under extreme cold conditions and experiments testing the effects of cool environments on thermoregulatory behaviour are surprisingly scarce. We conducted laboratory experiments to test if common lizards Zootoca
vivipara (an active thermoregulator in the field) are able to switch between active thermoregulation and thermoconformity in response to different thermal environments. We found that lizards in treatments with an opportunity to reach their preferred body temperature thermoregulated accurately, maintained their level of daily activity and improved their body condition considerably. In contrast, lizards in the treatment where the preferred body temperature could not be reached became thermoconformers, decreased their daily activity (except for gravid females) and did not increase their body condition. Our results show that lizards can indeed change their thermoregulatory strategy but stress that maintaining the preferred body temperature and, thus, optimising the physiological performance have high priority in lizard behaviour. 相似文献
192.
Hajo Holzmann Axel Munk Max Suster Walter Zucchini 《Environmental and Ecological Statistics》2006,13(3):325-347
We introduce a new class of circular time series based on hidden Markov models. These are compared with existing models, their
properties are outlined and issues relating to parameter estimation are discussed. The new models conveniently describe multi-modal
circular time series as dependent mixtures of circular distributions. Two examples from biology and meteorology are used to
illustrate the theory. Finally, we introduce a hidden Markov model for bivariate linear-circular time series and use it to
describe larval movement of the fly Drosophila.
Received: September 2003 / Revised: March 2004 相似文献
193.
Females ofBlattella germanica andBlaberus craniifer produce a volatile sex pheromone attractive at a distance for conspecific males. During the emission of the pheromone, females ofB. craniifer adopt a typical calling posture; we never observe such a stance inB. germanica females. For both species, the glandular structures responsible for pheromonal production are located on the female pygidium. InB. germanica, the thickness of the glandular epithelium is clearly correlated with the attractiveness of females, being maximum for 13 day old females. The functions of the pygidial glands are discussed in both species. 相似文献
194.
195.
The fetal behaviour of asymmetrical growth retarded fetuses was compared with that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and echographic examinations for two consecutive hours at 36–38 weeks of gestation. The distribution of gross fetal body movements, fetal breathing movements and fetal eye movements was analysed during the different fetal heart rate patterns. Furthermore, the incidence and organization of fetal behavioural states was investigated. The degree of vascular peripheral resistance was also evaluated by means of pulsed doppler ultrasonic equipmznt. Growth retarded fetuses were divided into two groups on the basis of the presence or absence of end diastolic flow in the fetal thoracic descending aorta. Growth retarded fetuses showed a delay in the integration of behavioural patterns and a lower coincidence of behavioural states. These findings are particularly evident in the fetuses with a severe increase of peripheral vascular resistance (absence of end diastolic flow in descending aorta). Thus, we suggest that a delay in central nervous system development is present in asymmetrical growth retarded fetuses and that there is a possible relationship of this delay to the degree of peripheral vascular resistance. 相似文献
196.
William J. de Groot Robert D. Field Michael A. Brady Orbita Roswintiarti Maznorizan Mohamad 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):165-180
Forest and land fires in Southeast Asia have many social, economic, and environmental impacts. Tropical peatland fires affect
global carbon dynamics, and haze from peat fires has serious negative impacts on the regional economy and human health. To
mitigate these fire-related problems, forest and land management agencies require an early warning system to assist them in
implementing fire prevention and management plans before fire problems begin. Fire Danger Rating Systems (FDRS) were developed
for Indonesia and Malaysia to provide early warning of the potential for serious fire and haze events. In particular, they
identify time periods when fires can readily start and spread to become uncontrolled fires and time periods when smoke from
smouldering fires will cause an unacceptably high level of haze. The FDRS were developed by adapting components of the Canadian
Forest Fire Danger Rating System, including the Canadian Forest Fire Weather Index (FWI) System and the Canadian Forest Fire
Behavior Prediction (FBP) System, to local vegetation, climate, and fire regime conditions. A smoke potential indicator was
developed using the Drought Code (DC) of the FWI System. Historical air quality analysis showed that the occurrence of severe
haze events increased substantially when DC was above 400. An ignition potential indicator was developed using the Fine Fuel
Moisture Code (FFMC) of the FWI System. Historical hot spot analysis, grass moisture, and grass ignition studies showed that
fire occurrence and the ability for grass fires to start and spread dramatically increased when FFMC > 82. The Initial Spread
Index (ISI) of the FWI System was used to develop a difficulty of control indicator for grassland fires, a fuel type that
can exhibit high rates of spread and fire intensity. This ISI-based indicator was developed using the grass fuel model of
the FBP System, along with a standard grass fuel load and curing level estimated from previous Indonesian studies. Very high
fire intensity is expected in grasslands when ISI ≥ 6. To provide early warning, the FDRS identifies classes of increasing
fire danger as the FFMC, DC, and ISI approach these key threshold values. The Indonesian FDRS is now operated nationally at
the Indonesian Meteorological and Geophysical Agency. The Malaysian Meteorological Service operates the Malaysian FDRS and
displays regional outputs for the Association of Southeast Asian Nations. The FDRS are being used by forestry, agriculture,
environment, and fire and rescue agencies to develop and implement fire prevention, detection, and suppression plans. 相似文献
197.
通过试点证明,建立并认证环境管理体系(ISO14000)对企业的好处是多方面的,特别对强化企业环境管理,改善企业环境行为,发迹企业形象起到了十分明显的作用,该文对如何在城市或区域建立环境管理体系作了一些探讨,首先就城市或区域建立环境管理体系的必要性与可能性进行了阐述,然后就其如何的基本思路,基本框架,以及思想与物质基础等作了较详细的论述,笔者认为,城市或区域推行ISO14000标准,应用把基点放在 相似文献
198.
Summary A crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C25:1), (Z)-13-C27:1, (Z)-13- and (Z)-14-C29:1. Synthetic monoenes were made, and only (Z)-11-C25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene. 相似文献
199.
Planqué R Dechaume-Moncharmont FX Franks NR Kovacs T Marshall JA 《Die Naturwissenschaften》2007,94(11):911-918
To perform tasks, organisms often use multiple procedures. Explaining the breadth of such behavioural repertoires is not always straightforward. During house hunting, colonies of Temnothorax albipennis ants use a range of behaviours to organise their emigrations. In particular, the ants use tandem running to recruit naïve ants to potential nest sites. Initially, they use forward tandem runs (FTRs) in which one leader takes a single follower along the route from the old nest to the new one. Later, they use reverse tandem runs (RTRs) in the opposite direction. Tandem runs are used to teach active ants the route between the nests, so that they can be involved quickly in nest evaluation and subsequent recruitment. When a quorum of decision-makers at the new nest is reached, they switch to carrying nestmates. This is three times faster than tandem running. As a rule, having more FTRs early should thus mean faster emigrations, thereby reducing the colony’s vulnerability. So why do ants use RTRs, which are both slow and late? It would seem quicker and simpler for the ants to use more FTRs (and higher quorums) to have enough knowledgeable ants to do all the carrying. In this study, we present the first testable theoretical explanation for the role of RTRs. We set out to find the theoretically fastest emigration strategy for a set of emigration conditions. We conclude that RTRs can have a positive effect on emigration speed if FTRs are limited. In these cases, low quorums together with lots of reverse tandem running give the fastest emigration. 相似文献
200.
In simultaneous hermaphrodites, gender conflicts that arise from two potential mates sharing the same gender preference may
be solved through conditional reciprocity (or gamete trading). Conditional reciprocity had initially been considered widespread,
but recent studies suggest that its real occurrence may have been overestimated, possibly because most mating observations
have been performed on isolated pairs of individuals. Some resulting patterns (e.g., non-random alternation of sexual roles)
were indeed compatible with conditional reciprocity but could also have stemmed from the two partners independently executing
their own mating strategy and being experimentally enforced to do so with the same partner. Non-random alternation of gender
roles was recently documented in the simultaneously hermaphroditic freshwater snail Physa acuta. To distinguish between conditional and unconditional gender alternations, we observed copulations of individually marked
snails reared at three contrasted densities. We showed that density affected the overall frequency of copulations during the
first 2 days of the experiment with high-density boxes showing more copulations than low density boxes, but it did not affect
gender alternation patterns. A change in gender role was observed more often than expected by chance over two successive copulations
by the same individual, confirming previous studies. However, gender switches did not preferentially occur with the same partner.
We conclude that gender alternation is not due to conditional reciprocity in P. acuta. It may rather stem from each individual having a preference for gender alternation. We finally discuss the mechanisms and
the potential extent of this unconditional reciprocity. 相似文献