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1.
Dale M. Jefferson Keith A. Hobson Brandon S. Demuth Maud C. O. Ferrari Douglas P. Chivers 《Die Naturwissenschaften》2014,101(4):291-303
Tadpoles show considerable behavioral plasticity. When population densities become high, tadpoles often become cannibalistic, likely in response to intense competition. Conspecific tissues are potentially an ideal diet by composition and should greatly improve growth and development. However, the potential release of alarm cues from the tissues of injured conspecifics may act to deter potential cannibals from feeding. We conducted multiple feeding experiments to test the relative effects that a diet of conspecifics has on tadpole growth and development. Results indicate that while conspecific tissues represent a better alternative to starvation and provide some benefits over low-protein diets, such a diet can have detrimental effects to tadpole growth and/or development relative to diets of similar protein content. Additionally, tadpoles raised individually appear to avoid consuming conspecific tissues and may continue to do so until they suffer from the effects of starvation. However, tadpoles readily fed upon conspecific tissues immediately when raised with competitors. These results suggest that cannibalism may occur as a result of competition rather than the specific quality of available diets, unless such diets lead to starvation. 相似文献
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洗发香波诱发蝌蚪红细胞微核的研究 总被引:2,自引:0,他引:2
研究了12种洗发香波对中华大蟾蜍蝌蚪红细胞微核的诱变效应。蝌蚪对各试验液中染毒7d,采心脏血制片。结果表明,8种洗发香波能诱发蝌蚪红细胞微核率显著升高,其致变效应与洗发香波浓度及染毒时间有关。 相似文献
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环境中的PAES对蟾蜍蝌蚪红细胞微核的影响研究 总被引:2,自引:0,他引:2
通过对邻苯二甲酸酯对蟾蜍蝌蚪红细胞微核的影响进行了研究。目的探讨邻苯二甲酸酯对蟾蜍蝌蚪的致突变作用。方法以邻苯二甲酸二甲酯为污染物对蟾蜍蝌蚪染毒24小时,并观察其细胞核变化。所用蟾蜍蝌蚪处于变态期,对污染物较为敏感。结果邻苯二甲酸酯使蟾蜍蝌蚪红细胞微核率以及核异常细胞率上升,微核率随着浓度的增大而上升,在浓度为78 ug/ml,对照组相比有极显著差异P〈0.01,浓度在18.5 ug/ml时试验组突变的细胞核的形态发生显著改变,核异常细胞率与对照组核异常细胞率有显著差异P〈0.05。此时显微镜下观察可见微核、双核、核内凹、核碎裂、无丝分裂时核分裂不均等核的形态变化。结论邻苯二甲酸酯对蟾蜍蝌蚪具有明显的致突变作用。 相似文献
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Young Nile crocodiles Crocodylus niloticus start to produce calls inside the egg and carry on emitting sounds after hatching. These vocalizations elicit maternal care
and influence the behaviour of other juveniles. In order to investigate the acoustic structure of these calls, focusing on
a possible individual signature, we have performed acoustic analyses on 400 calls from ten young crocodiles during the first
4 days after hatching. Calls have a complex acoustic structure and are strongly frequency modulated. We assessed the differences
between the calls of the individuals. We found a weak individual signature. An individual call-based recognition of young
by the mother is thus unlikely. In other respects, the call acoustic structure changes from the first to the fourth day after
hatching: fundamental frequency progressively decreases. These modifications might provide important information to the mother
about her offspring—age and size—allowing her to customize her protective care to best suit the needs of each individual.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献
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Polychlorinated biphenyls (PCBs) in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors (BCFs) of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author's conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners. 相似文献
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Chris R. Pavey Chris J. Burwell Gerhard Körtner Fritz Geiser 《Die Naturwissenschaften》2009,96(6):679-683
One of the energetic benefits of daily torpor over prolonged hibernation is that it enables animals to regularly forage and,
therefore, replenish food reserves between bouts of torpor. However, little is known about the diet of predators undergoing
torpor or whether differences in prey composition among individuals influence torpor characteristics. Here, we test the hypothesis
that prey composition affects winter torpor use and patterns of a population of carnivorous marsupial, the brush-tailed mulgara
(Dasycercus blythi), in the Great Sandy Desert, Australia. Mulgaras in the study population captured a wide range of prey including vertebrates
(mammals, reptiles, birds), seven insect orders, spiders and centipedes. The proportion of vertebrates in the diet was negatively
correlated with both frequency of torpor use and maximum bout duration. This variation in torpor use with diet can be explained
by the higher energetic content of vertebrates as well as their larger size. Even assuming uniform intake of prey biomass
among individuals, those that subsisted on an invertebrate-dominated diet during winter apparently suffered energetic shortages
as a result of the scarcity of invertebrate taxa with high energy content (such as insect larvae). Our study is the first
to demonstrate a link between diet composition and daily torpor use in a free-ranging mammal. 相似文献
10.
Nakano R Ishikawa Y Tatsuki S Surlykke A Skals N Takanashi T 《Die Naturwissenschaften》2006,93(6):292-296
Although sex pheromone communication in the genus Ostrinia (Lepidoptera: Crambidae) has been studied intensively, acoustic communication in this genus has not been explored. In this
study, we report that male-produced ultrasound serves as a courtship song in the Asian corn borer moth, O. furnacalis. Upon landing close to a pheromone-releasing female, a male showed a series of courtship behaviors involving emission of
ultrasound. The sounds were produced when the wings were vibrated quickly in an upright position. The male song was composed
of chirps, i.e., groups of pulses (duration of a chirp = 58.9 ms, 8.8 pulses/chirp), with a broadband frequency of 25–100 kHz.
In flight tunnel experiments, deaf and hearing females showed a significant difference in the incidence of three behavioral
responses to courting males, i.e., immediate acceptance, acceptance after walking, and rejection. Deaf females showed more
‘rejection’ and less ‘acceptance after walking’ than hearing females, indicating that the detection of male-produced ultrasound
plays an important role in the acceptance of a male. The findings are discussed in the context of exploitation of receiver
bias and mate choice. 相似文献
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Although amphibians are highly vocal, they generally emit only a limited number of acoustic communication signals. We report here the extraordinarily rich vocal repertoire of Amolops tormotus, a ranid species in China. These frogs produce countless vocalizations, some of which share features of birdsong or primate calls, e.g., ultrasonic frequency components, multiple upward and downward FM sweeps, and sudden onset and offset of selective harmonic components within a call note. Frame-by-frame video analysis of the frog's calling behavior suggests the presence of two pairs of vocal sacs that may contribute to the remarkable call-note complexity in this species. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-002-0335-x. 相似文献
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利用单颗粒气溶胶质谱仪研究燃煤尘质谱特征 总被引:3,自引:2,他引:1
采用单颗粒气溶胶质谱仪(SPAMS)和再悬浮采样器联用的方式对燃煤电厂烟道气样品和下载灰样品的质谱特征进行测定,并使用颗粒物粒径分级采样仪ELPI测定其粒径分布特征.研究表明,SPAMS监测得到的粒径分布与ELPI结果差异较大,SPAMS对于500 nm以上粒径段检测效果较好;两个样品正谱图中有非常明显的锂、钙、钛、铝等金属组分信号和碳组分信号特征,负谱图中硅酸盐、硝酸盐和硫酸盐等信号比较明显,并且随着粒径的增加碳组分、硫酸盐和硝酸盐等组分对应的信号强度逐渐减弱,而硅酸盐、铝、钙和钛等组分对应的信号强度逐渐增强;对两个样品使用ART-2a聚类获得多个颗粒物类别,分析表明,它们均含有元素碳二次类(硫酸盐和硝酸盐缩写为二次Sec)、有机碳二次类、铝元素碳类、铝钙硅酸盐类和富硅酸盐类等颗粒物类别,并且随着粒径的增加金属硅酸盐颗粒出现频率增大,而含碳颗粒与硫酸盐出现频率降低.但烟道气样品和下载灰样品的质谱特征呈显著差异,下载灰样品更能代表燃煤源真实排放特征.建议在今后建立基于单颗粒质谱固定源成分谱时,应使用单颗粒气溶胶质谱仪在外场进行实测,并使用聚类的方法提取不同粒径段上的源质谱特征,可能会取得更好的效果. 相似文献
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Xiaofei Qin Xijuan Xi Zhongzhi Yang Shishuai Yan Yaxian Zhao Rongguo Wei Yan Li Mi Tian Xingru Zhao Zhanfen Qin Xiaobai Xu 《环境科学学报(英文版)》2010,22(5):744-751
Decabromodiphenyl ether (decaBDE), as a flame retardant, is widely produced and used. To study the thyroid disruption by technical
decaBDE at low concentrations, Xenopus laevis tadpoles were exposed to technical decaBDE mixture DE-83R (1–1000 ng/L) in
water from stage 46/47 (free swimming larvae, system of Nieuwkoop and Faber) to stage 62. DE-83R at concentration of 1000 ng/L
significantly delayed the time to metamorphosis (presented by forelimb emergence, FLE). Histological examination showed that DE-
83R at all tested concentrations caused histological alterations – multilayer follicular epithelial cell and markedly increased follicle size
accompanied by partial colloid depletion and increase in the peripheral colloid vacuolation, in thyroid glands. All tested concentrations
of DE-83R also induced a down-regulation of thyroid receptor mRNA expression. These results demonstrated that technical decaBDE
disrupted the thyroid system in X. laevis tadpoles. Analysis of polybrominated diphenyl ethers (PBDEs) (sum of 39 congeners) in X.
laevis indicated that mean concentrations of total PBDEs in X. laevis exposed to 1, 10, 100, 1000 ng/L were 11.0, 128.1, 412.1, 1400.2
ng/g wet weight, respectively. Considering that PBDEs burden of X. laevis tadpoles was close to PBDEs levels in amphibians as reported
in previous studies, our study has raised new concerns for thyroid disruption in amphibians of technical decaBDE at environmentally
relevant concentrations. 相似文献
14.
Discriminating nestmates from alien conspecifics via chemical cues is recognized as a critical element in maintaining the integrity of insect societies. We determined, in laboratory experiments, that nestmate recognition in an introduced population of the Argentine ant, Linepithema humile, is modified by hydrocarbons acquired from insect prey, and that workers from spatially isolated colony fragments, each provided with prey that possessed distinct cuticular hydrocarbons, displayed aggressive behavior towards their former nestmates. Isolation for 28 days or more between colony fragments fed different prey was sufficient to prevent re-establishment of inter-nest communication for at least an additional 28 days through the introduction of a bridge between the nests. Ants possessed intrinsic cuticular hydrocarbons plus only those hydrocarbons from the prey they received during the isolation period. Colony fragments which were isolated for less than 28 days reunited with workers possessing both prey hydrocarbons. Therefore, L. humile nestmate recognition may be dynamic, being in part dependent on the spatio-temporal distribution of prey, along with physical factors permitting or restricting access of subcolony units to those prey. 相似文献
15.
Ilya A. Volodin Vera A. Matrosova Roland Frey Julia D. Kozhevnikova Inna L. Isaeva Elena V. Volodina 《Die Naturwissenschaften》2018,105(7-8):40
Non-hibernating pikas collect winter food reserves and store them in hay piles. Individualization of alarm calls might allow discrimination between colony members and conspecifics trying to steal food items from a colony pile. We investigated vocal posture, vocal tract length, and individual acoustic variation of alarm calls, emitted by wild-living Altai pikas Ochotona alpina toward a researcher. Recording started when a pika started calling and lasted as long as possible. The alarm call series of 442 individual callers from different colonies consisted of discrete short (0.073–0.157 s), high-frequency (7.31–15.46 kHz), and frequency-modulated calls separated by irregular intervals. Analysis of 442 discrete calls, the second of each series, revealed that 44.34% calls lacked nonlinear phenomena, in 7.02% nonlinear phenomena covered less than half of call duration, and in 48.64% nonlinear phenomena covered more than half of call duration. Peak frequencies varied among individuals but always fitted one of three maxima corresponding to the vocal tract resonance frequencies (formants) calculated for an estimated 45-mm oral vocal tract. Discriminant analysis using variables of 8 calls per series of 36 different callers, each from a different colony, correctly assigned over 90% of the calls to individuals. Consequently, Altai pika alarm calls are individualistic and nonlinear phenomena might further increase this acoustic individualization. Additionally, video analysis revealed a call-synchronous, very fast (0.13–0.23 s) folding, depression, and subsequent re-expansion of the pinna confirming an earlier report of this behavior that apparently contributes to protecting the hearing apparatus from damage by the self-generated high-intensity alarm calls. 相似文献
16.
Laura Rodríguez-Loeches Alejandro Barro Martha Pérez Frank Coro 《Die Naturwissenschaften》2009,96(4):531-536
Both sexes of Phoenicoprocta capistrata have functional tymbals. The scanning electron microscopy revealed differences in the morphology of these organs in males
and females. Male tymbals have a well-developed striated band, constituted by 21 ± 2 regularly arranged striae whereas female
tymbals lack a striated band. This type of sexual dimorphism is rare in Arctiidae. The recording of the sound produced by
moths held by the wings revealed that while males produced trains of pulses organized in modulation cycles, females produced
clicks at low repetition rate following very irregular patterns. Statistically, there are differences between sexes in terms
of the duration of pulses, which were 355 ± 24 μs in the case of males and 289 ± 29 μs for females. The spectral characteristics
of the pulses also show sexual dimorphism. Male pulses are more tuned (Q
10 = 5.2 ± 0.5) than female pulses (Q
10 = 2.7 ± 0.5) and have a higher best frequency (42 ± 1 kHz vs. 29 ± 2 kHz). To our knowledge, this is the first report on
an arctiid moth showing sexual dimorphism in tymbal’s anatomy that leads to a best frequency dimorphism. Males produce sound
at mating attempts. The sounds recorded during mating are modulation cycles with the same spectral characteristics as those
recorded when males are held by the wings. The morphological and acoustic features of female tymbals could indicate a process
of degeneration and adaptation to conditions under which the emission of complex patterns is not necessary.
Frank Coro no longer works at Universidad de La Habana. 相似文献
17.
Efremova KO Volodin IA Volodina EV Frey R Lapshina EN Soldatova NV 《Die Naturwissenschaften》2011,98(11):919-931
In goitred gazelles (Gazella subgutturosa), sexual dimorphism of larynx size and position is reminiscent of the case in humans, suggesting shared features of vocal
ontogenesis in both species. This study investigates the ontogeny of nasal and oral calls in 23 (10 male and 13 female) individually
identified goitred gazelles from shortly after birth up to adolescence. The fundamental frequency (f0) and formants were measured
as the acoustic correlates of the developing sexual dimorphism. Settings for LPC analysis of formants were based on anatomical
dissections of 5 specimens. Along ontogenesis, compared to females, male f0 was consistently lower both in oral and nasal
calls and male formants were lower in oral calls, whereas the first two formants of nasal calls did not differ between sexes.
In goitred gazelles, significant sex differences in f0 and formants appeared as early as the second week of life, while in
humans they emerge only before puberty. This result suggests different pathways of vocal ontogenesis in the goitred gazelles
and in humans. 相似文献
18.
Gong Peiyu Wu Kunjun Li XiuzhenInstitute of Zoology Chinese Academy of Sciences Beijing China. 《环境科学学报(英文版)》1993,(2)
SO2 Pollution; rape plant (Brassica chinensis); turnip moth (Agrotis segetum); growth and developmental parameters. 相似文献
19.
The larvae of the sawfly Rhadinoceraea micans live and feed on a semi-aquatic plant, Iris pseudacorus, and their integument is strongly hydrophobic. The hydrophobicity is part of a chemical defence strategy, easy bleeding, also known from congeners. The prepupae burrow into the soil where they form a cocoon in which they pupate, thus implying different micro-environmental conditions. The cuticle structure and wetting defensive effectiveness of R. micans were compared between larvae and prepupae. The two stages were similarly well defended against attacking ants by the bleeding of a deterrent hemolymph, whereas they were dissimilar in the cuticle surface that presented sculptures and wax crystals at the larval stage only. The integument of prepupae was less structured, and hydrophilic. Larvae of R. micans exhibit, among sawflies, an exceptional cuticle structuring and we assume that they occupy this particular niche of a semi-aquatic environment to avoid encounters with ground-dwelling predators whereas prepupae may benefit from the chemical defence acquired at larval stage. 相似文献
20.
ter Hofstede HM Goerlitz HR Montealegre-Z F Robert D Holderied MW 《Die Naturwissenschaften》2011,98(12):1057-1061
Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat
detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid
tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser
Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that
were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at
the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the
key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement,
not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and
recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity
or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating
that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold. 相似文献