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101.
In monogamous species, females often choose between males according to the quality of the territories they defend, but the
extent to which females themselves contribute to territory defence is frequently underestimated. Here we test for differences
in male and female roles during paired scent-marking bouts, a key component of territorial defence, in a monogamous antelope.
In two populations (Kenya, Zimbabwe) of klipspringer, Oreotragus oreotragus, both males and females usually scent-marked at the same site, but there were significant differences between sexes in terms
of investment within bouts. Females initiated most bouts, thus dictating the marking strategy of the pair. Males initiated
relatively few bouts, but deposited more scent marks per bout than females and were usually the last to scent-mark before
leaving the site; they marked on the same branches as the female and thus overmarked her scent. Both sexes deposited more
marks during paired than solo visits. Immediately preceding and following scent-marking bouts, males approached females and
females left males more often than expected. Female scent-marking rates were higher when they were receptive than at other
times, and this increase was matched by elevated marking rates of males. Females may increase marking rates when they are
receptive in order to test the quality of their mate or to incite male competition. However, these ideas are unlikely to explain
female scent-marking behaviour outside the mating season, which appears to be related primarily to territorial defence. We
suggest that these differences in investment in scent-marking bouts are consistent with predictions that females may be autonomously
territorial and that overmarking of female scent by males is a form of mate-guarding.
Received: 17 November 1999 / Received in revised form: 24 February 2000 / Accepted: 13 March 2000 相似文献
102.
The modulation of worker behavior by the vibration signal during house hunting in swarms of the honeybee, Apis mellifera 总被引:3,自引:3,他引:0
During house hunting, honeybee, Apis melli- fera, workers perform the vibration signal, which may function in a modulatory manner to influence several aspects of nestsite
selection and colony movement. We examined the role of the vibration signal in the house-hunting process of seven honeybee
swarms. The signal was performed by a small proportion of the older bees, and 20% of the vibrating bees also performed waggle
dances for nestsites. Compared to non-vibrating controls, vibrating bees exhibited increased rates of locomotion, were more
likely to move into the interiors of the swarms, and were more likely to fly from the clusters and perform waggle dances.
Recipients responded to the signal with increased locomotion and were more likely than non- vibrated controls to fly from
the swarms. Because vibration signals were intermixed with waggle dances by some vibrators, and because they stimulated flight
in recipients, the signals may have enhanced nestsite scouting and recruitment early in the house-hunting process. All swarms
exhibited increased vibration activity within 0.5–1 h of departure. During these final periods, numerous vibrating bees wove
repeatedly in and out of the clusters while signaling and motion on the swarms increased until it culminated in mass flight.
The peaks of vibration activity observed at the end of the house-hunting process may therefore have activated the entire swarm
for liftoff once a new nestsite had been selected. Thus, the vibration signal may help to integrate the behavior of numerous
groups of workers during nestsite selection and colony relocation.
Received: 17 January 2000 / Received in revised form: 5 April 2000 / Accepted: 3 May 2000 相似文献
103.
A. Kunwar 《International Journal of Green Energy》2016,13(4):335-343
High penetration level of wind power has significant impact on the dynamic performance of power system. Power system with existing high-voltage direct current (HVDC) link may influence the stability of power system at high penetration level of wind power. This article investigates the stability issues of power system with existing HVDC link for different penetration level of doubly fed induction generator (DFIG) and direct drive synchronous generator (DDSG) based wind farms. The small signal stability analysis shows that power system with HVDC link has improved the stability of the power system for increased penetration of DFIG- and DDSG-based wind farms. 相似文献
104.
SO2是一种常见的大气污染物,急性和慢性暴露都会对植物造成伤害.因此,本文以景观绿化植物萱草叶片下表皮为材料,研究了SO2对气孔保卫细胞的致死效应及其可能的信号调节途径.结果表明,利用SO2体内衍生物-亚硫酸钠和亚硫酸氢钠混合液处理萱草表皮3 h后,随着处理浓度(1.0~5.0 mmol·L-1)的增加,萱草保卫细胞生理活性下降,甚至死亡;浓度超过2.0 mmol·L-1时,细胞死亡率显著增高(p0.05),死细胞出现核固缩、核拉长、核碎片等典型凋亡特征,保卫细胞内的活性氧种(ROS)、一氧化氮(NO)和Ca2+水平显著升高.采用不同浓度的抗氧化剂过氧化氢酶(CAT)、抗坏血酸(AsA),Ca2+螯合剂乙二醇双四乙酸(EGTA)和Ca2+通道抑制剂氯化镧(LaCl3)及NO清除剂羧基-2苯-4,4,5,5-四甲基咪唑-1-氧-3氧化物(C-PTIO)和合成抑制剂叠氮钠(NaN3)处理后,均可使SO2衍生物诱发的细胞死亡率降低,以200 U·mL-1CAT、0.05 mmol·L-1的AsA、EGTA、LaCl3及0.20 mmol·L-1的C-PTIO、NaN3的效果最佳,同时胞内ROS、NO和Ca2+水平下降.以上结果表明,一定浓度的SO2可诱导萱草保卫细胞死亡,可能通过诱导ROS和NO爆发,激活细胞质膜钙通道,进而引起胞内Ca2+增加,通过ROS-NO-Ca2+信号途径介导细胞死亡.SO2诱导的萱草细胞死亡可能存在细胞凋亡过程. 相似文献
105.
106.
107.
硝化细菌生长缓慢、同化效率低、环境敏感性高,并且高氨氮废水中存在大量的游离氨会对硝化细菌活性产生抑制作用。本实验采用序批式反应器,研究添加C7-HSL、C8-HSL和3-oxo-C10-HSL对活性污泥处理高氨氮废水的影响。结果表明,信号分子可以显著促进微生物的生长,有效提高亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)的活性,同时可促进胞外聚合物(extracellular polymeric substance,EPS)的形成,改变EPS的组成,从而有效缓解高${{\rm{NO}}_2^{-}} $ -N对系统的抑制,说明信号分子有利于微生物对抗不利的环境条件,缩短系统达到稳定的时间。其中C7-HSL效果最显著,污泥平均生长速率提升35.20%,降解效率提高17.52%,同时EPS增长了35.45%,蛋白质/多糖显著提升,并促进了色氨酸类氨基酸和腐殖酸的形成。以上研究结果可为处理高氨氮废水提供一种新的调控策略。 相似文献
108.
James C. Nieh 《Behavioral ecology and sociobiology》1998,42(1):23-36
This study explores the meaning and functional design of a modulatory communication signal, the honey bee shaking signal,
by addressing five questions: (I) who shakes, (II) when do they shake, (III) where do they shake, (IV) how do receivers respond
to shaking, and (V) what conditions trigger shaking. Several results confirm the work of Schneider (1987) and Schneider et
al. (1986a): (I) most shakers were foragers (at least 83%); (II) shaking exhibited a consistent temporal pattern with bees
producing the most signals in the morning (0810–1150 hours) just prior to a peak in waggle dancing activity; and (IV) bees
moved faster (by 75%) after receiving a shaking signal. However, this study differs from previous work by providing a long-term,
temporal, spatial, and vector analysis of individual shaker behavior. (III) Bees producing shaking signals walked and delivered
signals in all areas of the hive, but produced the most shaking signals directly above the waggle dance floor. (IV) Bees responded
to the signal by changing their direction of movement. Prior to receiving a signal, bees selected from the waggle dance floor
moved, on average, towards the hive exit. After receiving a signal, some bees continued moving towards the exit but others
moved directly away from the exit. During equivalent observation periods, non-shaken bees exhibited a strong tendency to move
towards the hive exit. (V) Renewed foraging activity after food dearth triggered shaking signals, and, the level of shaking is positively correlated with the duration of food dearth. However, shaking signal levels also increased in the morning before foraging had begun and in the late afternoon
after foraging had ceased. This spontaneous afternoon peak has not previously been reported. The shaking signal consequently
appears to convey the general message “reallocate labor to different activities” with receiver context specifying a more precise
meaning. In the context of foraging, the shaking signal appears to activate (and perhaps deactivate) colony foraging preparations.
The generally weak response elicited by modulatory signals such as the shaking signal may result from a high receiver response
threshold which allows the receiver to integrate multiple sources of information and which thereby increases the probability
that receiver actions will be appropriate to colony needs.
Received: 21 March 1997 / Accepted after revision: 30 August 1997 相似文献
109.
D. S. Pope 《Behavioral ecology and sociobiology》2000,47(6):432-437
Many territorial advertisement signals are thought to be dual-function signals, directed to both rival male and receptive
female conspecifics. However, few studies have tested this assumption by examining whether in fact both sexes are likely to
elicit signaling behavior from territorial males. In this study, I experimentally manipulated the social context of male sand
fiddler crabs (Uca pugilator) to investigate the effect of different audiences on the performance of the claw-waving display, a territorial signal that
is often presumed to be directed to both males and females. To test whether males perform this signal to both audiences, I
measured the frequency of waving behavior by focal males when housed in field enclosures alone, with only males, with only
females, or with both males and females. Focal males waved at a low frequency when alone, and the presence of males had no
effect on their level of waving. However, in the presence of females, focal males showed a significantly higher level of waving,
whether or not males were also present. In addition, there was no association between fighting and waving behavior. This experiment
provides evidence that from the perspective of the signaling male, the claw-waving display of U. pugilator is not a dual-function signal but rather is primarily directed to receptive females.
Received: 16 December 1999 / Received in revised form: 1 February 2000 / Accepted: 19 February 2000 相似文献
110.
Categorization of the status of populations, species, and ecosystems underpins most conservation activities. Status is often based on how a system's current indicator value (e.g., change in abundance) relates to some threshold of conservation concern. Receiver operating characteristic (ROC) curves can be used to quantify the statistical reliability of indicators of conservation status and evaluate trade‐offs between correct (true positive) and incorrect (false positive) classifications across a range of decision thresholds. However, ROC curves assume a discrete, binary relationship between an indicator and the conservation status it is meant to track, which is a simplification of the more realistic continuum of conservation status, and may limit the applicability of ROC curves in conservation science. We describe a modified ROC curve that treats conservation status as a continuum rather than a discrete state. We explored the influence of this continuum and typical sources of variation in abundance that can lead to classification errors (i.e., random variation and measurement error) on the true and false positive rates corresponding to varying decision thresholds and the reliability of change in abundance as an indicator of conservation status, respectively. We applied our modified ROC approach to an indicator of endangerment in Pacific salmon (Oncorhynchus nerka) (i.e., percent decline in geometric mean abundance) and an indicator of marine ecosystem structure and function (i.e., detritivore biomass). Failure to treat conservation status as a continuum when choosing thresholds for indicators resulted in the misidentification of trade‐offs between true and false positive rates and the overestimation of an indicator's reliability. We argue for treating conservation status as a continuum when ROC curves are used to evaluate decision thresholds in indicators for the assessment of conservation status. Determinación de Umbrales de Decisiones y Evaluación delos Indicadores cuando se Mide el Estado de de Conservación como un Continuo 相似文献