柑橘凤蝶蛹发声器的显微结构及防御作用(英文)

【目的】动物界存在多种用于对抗捕食者的防御机制。一些鳞翅目昆虫的蛹在受到机械刺激时会发出蠕动的声音。【方法】在扫描电镜下对柑橘凤蝶Papilio xuthus蛹的发声器形态特征进行观察,并使用Audacity软件对捕获的声音进行特征分析。【结果】柑橘凤蝶蛹在腹部第4-5节和第5-6节之间的节间膜上存在发声器,有规律地发出嘶嘶声。发声器由多层甲壳素构成的刮器和板组成,刮器和板上有 50~90个突起。当蛹的腹部被寄生蜂触角刺激30 s以上时,刮器和板会迅速相互摩擦,腹部反复摆动发出声音。蛹发出的声音是由一系列每2 000~3 000 ms发生3次的短脉冲组成的。频带很宽,主要分布在5~20kHz范围内。新鲜蛹和越冬蛹的活性不同,声强也不同。【结论】本研究首先描述了柑橘蝴蝶蛹发声器的结构,结果支持了一些蝴蝶蛹对寄生生物进化出一种特殊的防御机制(声学防御)的假说。此外,通过比较两种生境的柑橘凤蝶蛹的声波特征,我们提出了同一物种在不同地理区域可以产生方言的假说。 关键词:     

Call types of Bigg’s killer whales (Orcinus orca) in western Alaska: using vocal dialects to assess population structure

Bigg’s killer whales (Orcinus orca; i.e. ‘transient’ ecotype), as apex predators, are important to the dynamics of marine ecosystems, but little is known about their population structure in western Alaska. Currently, all Bigg’s killer whales in western Alaska are ascribed to a single broad stock for management under the US Marine Mammal Protection Act. However, recent nuclear microsatellite and mitochondrial DNA analyses indicate that this stock is likely comprised of genetically distinct sub-populations. In accordance with what is known about killer whale vocal dialects in other locations, we used the spatial distribution of group-specific call types to investigate the population structure of Bigg’s killer whales in this part of Alaska. Digital audio recordings were collected from 33 Bigg’s killer whale encounters throughout the Aleutian and Pribilof Islands in the summers of 2001–2007 and 2009–2010. Recorded calls were qualitatively classified into discrete types and then quantitatively described using 12 structural and time-frequency measures. Resulting call categories were validated using a random forest approach. A total of 36 call types and subtypes were identified across the entire study area, and regional patterns of call type use revealed three distinct dialects which correspond to proposed genetic delineations. Our results suggest that there are at least three acoustically and genetically distinct sub-populations in western Alaska, and we present an initial catalogue for this area describing the regional vocal repertoires of Bigg’s killer whale call types.     

杭州市区白头鹎鸣声的微地理差异

2002年5—8月,对中国东部浙江省杭州市区的白头鹎鸣声的微地理差异进行研究。在约60 km2的 研究区内,选择8个调查点(4个城区,4个丘陵山地),录制了80个雄性白头鹎的511个鸣声样本,并随机选 取每一调查点的20个鸣声样本进行分析。其结果显示,白头鹎在杭州市区至少有8种微地理鸣声方言,每个微 地理鸣声方言都有一典型鸣句;它们在听觉上、波形结构、音节组成、音节频谱特征等方面均不相同。有的一 路之隔的相邻微地理鸣声方言之间存在明显差异;部分区域出现鸣声混合现象;有的个体还具有“多语”功 能。白头鹎鸣声产生微地理差异的原因可能与鸟类个体的扩散和城市中鸟类栖息地的人为改变有关。     

Coevolution of DNA-interacting proteins and genome "dialect"

Several species-specific characteristics of genome organization that are superimposed on its coding aspects were proposed earlier, including genome signature (GS), genome accent, and compositional spectrum (CS). These notions could be considered as representatives of genome dialect (GD). We measured within the Proteobacteria some GD representatives, the relative abundance of dinucleotides or GS, the profiles of occurrence of 10 nucleotide words (CS), and the profiles of occurrence of 20 nucleotide words, using a degenerate two-letter alphabet (purine-pyrimidine compositional spectra [PPCS]). Here, we show that the evolutionary distances between DNA repair and recombination orthologous enzymes (especially those of the nucleotide excision repair system) are highly correlated with PPCS and GS distances. Orthologous proteins involved in structural or metabolic processes (control group) have significantly lower correlations of their evolutionary distances with the PPCS and GS distances. We hypothesize that the high correlation of the evolutionary distances of the DNA repair orthologous enzymes with their GD is a result of the coevolution of the DNA repair enzymes' structures and GDs. Species GDs could be substantially influenced by the function of DNA polymerase I (the bacterial major DNA repair polymerase). This might cause the correlation of species GDs differentiation with evolutionary changes of species DNA polymerase I. Simultaneously, the structures of DNA repair-recombination enzymes might be evolutionarily sensitive and responsive to changes in the structure of their substrate-the DNA (including those that are represented by GD differentiation). We further discuss the rationale and mechanisms of the hypothesized coevolution. We suggest that stress might be an important cause of changes in the repair-recombination genes and the GD and the trigger of the aforementioned coevolution process. Other triggers might be massive horizontal gene transfer and ecological selection.     

Urban noise and the cultural evolution of bird songs

In urban environments, anthropogenic noise can interfere with animal communication. Here we study the influence of urban noise on the cultural evolution of bird songs. We studied three adjacent dialects of white-crowned sparrow songs over a 30-year time span. Urban noise, which is louder at low frequencies, increased during our study period and therefore should have created a selection pressure for songs with higher frequencies. We found that the minimum frequency of songs increased both within and between dialects during the 30-year time span. For example, the dialect with the highest minimum frequency is in the process of replacing another dialect that has lower frequency songs. Songs with the highest minimum frequency were favoured in this environment and should have the most effective transmission properties. We suggest that one mechanism that influences how dialects, and cultural traits in general, are selected and transmitted from one generation to the next is the dialect''s ability to be effectively communicated in the local environment.     

Vocal dialects, sex-biased dispersal, and microsatellite population structure in the parrot Amazona auropalliata

Geographic variation in microsatellite allele frequencies was assessed at nine sites in two regional vocal dialects of the parrot Amazona auropalliata (yellow-naped amazon) to test for correspondence between dialects and population structure. There was no relationship between the genetic distances between individuals and their dialect membership. High rates of gene flow were estimated between vocal dialects based on genetic differentiation. In addition, 5.5% of pairs of individuals compared across the dialect boundary were estimated to be related at the level of half siblings, indicating that dispersal is ongoing. The number of effective migrants per generation between dialects estimated with the microsatellite data was roughly one-seventh the number estimated with mitochondrial control region sequence data from the same individuals, suggesting that gene flow may be female-biased. Together, these results suggest that the observed mosaic pattern of geographic variation in vocalizations is maintained by learning of local call types by immigrant birds after dispersal. We found no evidence that ongoing habitat fragmentation has contributed to cryptic population structure.     

Vocal culture in New Caledonian crows Corvus moneduloides

While recent research suggests that some animal species may possess ‘cultural’ traditions, much of the current evidence for wild populations remains contentious. This is largely due to the difficulty of demonstrating a fundamental prerequisite for the existence of culture: social learning. As the only case where social learning has been demonstrated conclusively, and subsequently linked to spatial or temporal trait variation, avian vocal dialects are the best studied, and most widely accepted, form of animal culture. Here, we investigate the potential for vocal culture in one of the few animals for which material culture has been suggested: the New Caledonian crow Corvus moneduloides. We show that this species: (1) possesses the capacity for social learning of vocalizations (experimental evidence in the form of a captive subject that reproduces human speech and other anthropogenic noises); and (2) exhibits significant large‐scale, population‐level variation in its vocalizations (cross‐island playback experiments, with analyses controlling for a substantial set of potentially confounding variables). In combination, this provides strong evidence for the existence of ‘culture’ in these birds. More specifically, our findings reveal that the species exhibits sufficient social learning mechanisms, and within‐population structuring, to generate and perpetuate cultural variation in at least one behavioural domain. This is a critical first step towards demonstrating cultural transmission in other behaviours, including tool manufacture and tool use, opening the door for the simultaneous investigation of vocal and material culture in a nonhuman species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 767–776.