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631.
This is the first report of gynandromorphy in Isoptera. An Asian dry-wood termite, Neotermes koshunensis (Shiraki) [Kalotermitidae], possessing both male and female phenotypic characteristics, was found on Okinawa Island, Japan. This deformed individual showed morphological and anatomical hermaphroditism in the abdomen. The right side of the seventh sternite was the female form and contained an ovary, while the left side was the male form and contained a testis. Genotypic analysis revealed that this individual was a genotypic bilateral chimera. These results suggested that the termite was a bilateral gynandromorph with a male left side and a female right side. As reported previously in other insects, double fertilization (by two sperms, one with an X and one with a Y chromosome) of a binucleate egg is the most likely mechanism that generated this genotypic bilateral chimera. N. koshunensis has the ability to reproduce through parthenogenesis, in which the secondary polar body is likely to be used for nuclear phase recovery. If the second polar body in this mechanism has high fertility and healthy embryogenic potential, like an egg nucleus, some of gynandromorphs might be produced by a side effect of parthenogenetic ability. 相似文献
632.
Emerging evidence suggests the occurrence of comparative decision-making processes in mate choice, questioning the traditional idea of female choice based on rules of absolute preference. In such a scenario, females are expected to use a typical best-of-n sampling strategy, being able to recall previous sampled males based on memory of their quality and location. Accordingly, the quality of preferred mate is expected to be unrelated to both the number and the sequence of female visits. We found support for these predictions in the peacock blenny, Salaria pavo, a fish where females have the opportunity to evaluate the attractiveness of many males in a short time period and in a restricted spatial range. Indeed, even considering the variability in preference among females, most of them returned to previous sampled males for further evaluations; thus, the preferred male did not represent the last one in the sequence of visited males. Moreover, there was no relationship between the attractiveness of the preferred male and the number of further visits assigned to the other males. Our results suggest the occurrence of a best-of-n mate sampling strategy in the peacock blenny. 相似文献
633.
Julien Benoit Sandra C. Jasinoski Vincent Fernandez Fernando Abdala 《Die Naturwissenschaften》2017,104(7-8):66
The basal non-mammaliaform cynodonts from the late Permian (Lopingian) and Early Triassic are a major source of information for the understanding of the evolutionary origin of mammals. Detailed knowledge of their anatomy is critical for understanding the phylogenetic transition toward mammalness and the paleobiological reconstruction of mammalian precursors. Using micro-computed tomography (μCT), we describe the internal morphology of the interorbital region that includes the rarely fossilized orbitosphenoid elements in four basal cynodonts. These paired bones, which are positioned relatively dorsally in the skull, contribute to the wall of the anterior part of the braincase and form the floor for the olfactory lobes. Unlike procynosuchids and the more basal therapsids in which the orbitosphenoids are well developed, dense, and bear a ventral keel, the basal epicynodonts Cynosaurus, Galesaurus, and Thrinaxodon display cancellous, reduced, and loosely articulated orbitosphenoids, a condition shared with many eucynodonts. The hemi-cylindrical orbitosphenoid from which the mammalian condition is derived re-evolved convergently in traversodontid and some probainognathian cynodonts. 相似文献
634.
To explore the role of the volatiles emitted from male labial gland (LG) of the bumblebee Bombus ardens ardens, we investigated the responses of virgin queens and males to volatiles using a gas chromatography–electroantennographic detector (GC–EAD) system and Y-tube olfactometer. GC–EAD analysis revealed that citronellol, the main compound detected in the male LG, caused clear electrophysiological responses in the antennae of B. a. ardens virgin queens and males although two minor compounds elicited antennal responses when applied in a high concentration. Behavioral tests using a Y-tube olfactometer showed that queens and males were significantly attracted to both LG extracts and citronellol more than to the solvent alone. This is the first study to demonstrate that citronellol as a major compound of male scent-marking pheromone in B. a. ardens functions as a sex attractant for queens. The results also suggest that this compound has another function as a trail marker used by males. 相似文献
635.
Marco Basile Antonio Romano Andrea Costa Mario Posillico Daniele Scinti Roger Aldo Crisci Ranieri Raimondi Tiziana Altea Vittorio Garfì Giovanni Santopuoli Marco Marchetti Sebastiano Salvidio Bruno De Cinti Giorgio Matteucci 《Die Naturwissenschaften》2017,104(9-10):80
Many small terrestrial vertebrates exhibit limited spatial movement and are considerably exposed to changes in local environmental variables. Among such vertebrates, amphibians at present experience a dramatic decline due to their limited resilience to environmental change. Since the local survival and abundance of amphibians is intrinsically related to the availability of shelters, conservation plans need to take microhabitat requirements into account. In order to gain insight into the terrestrial ecology of the spectacled salamander Salamandrina perspicillata and to identify appropriate forest management strategies, we investigated the salamander’s seasonal variability in habitat use of trees as shelters in relation to tree features (size, buttresses, basal holes) and environmental variables in a beech forest in Italy. We used the occupancy approach to assess tree suitability on a non-conventional spatial scale. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander’s terrestrial ecology. Occupancy changed with the annual life cycle and was higher in autumn than in spring, when females were found closer to the stream in the study area. Salamanders showed a seasonal pattern regarding the trees they occupied and a clear preference for trees with a larger diameter and more burrows. With respect to forest management, we suggest maintaining a suitable number of trees with a trunk diameter exceeding 30 cm. A practice of selective logging along the banks of streams could help maintain an adequate quantity of the appropriate microhabitat. Furthermore, in areas with a presence of salamanders, a good forest management plan requires leaving an adequate buffer zone around streams, which should be wider in autumn than in spring. 相似文献
636.
Poor early-life nutrition could reduce adult reproductive success by negatively affecting traits linked to sexual attractiveness such as song complexity. If so, this might favor strategic mate choice, allowing males with less complex songs to tailor their mating tactics to maximize the reproductive benefits. However, this possibility has been ignored in theoretical and empirical studies. By manipulating the micronutrient content of the diet (e.g., low or high) during the postnatal period of male zebra finches, we show for the first time (1) that males reared on a poor (low) micronutrient diet had less complex songs as adults; (2) that these males, in contrast to the high micronutrient diet group, were more selective in their mating strategies, discriminating against those females most likely to reduce their clutch size when paired with males having less complex songs; and (3) that by following different mating strategies, males reared on the contrasting diets obtained similar reproductive benefits. These results suggest that early-life dietary conditions can induce multiple and long-lasting effects on male and female reproductive traits. Moreover, the results seem to reflect a previously unreported case of adaptive plasticity in mate choice in response to a nutritionally mediated reduction in sexual attractiveness. 相似文献
637.
废旧锌锰电池生物淋滤-水热法制备纳米锰锌铁氧体 总被引:3,自引:2,他引:1
以氧化硫硫杆菌(A.thiooxidans)和氧化亚铁钩端螺旋菌(L.ferrooxidans)为混合淋滤菌株对废旧锌锰电池进行了生物浸提,并以获取的淋滤液为前驱体,采用水热法制备出系列锰锌铁氧体软磁材料(Mn_(1-x)Zn_xFe_2O_4,x=0.2~0.8);结合X射线衍射(XRD)、扫描电镜-能谱(SEMEDX)、振动样品磁强计(VSM)、透射电镜(TEM)、红外光谱(FT-IR)、热重-差热分析(TG-DTA)等表征手段对制备材料的结构、形貌、磁学性能和稳定性进行分析.结果表明,在5%固液比(质量体积比,5 g/100 mL,以下均表述为"5%固液比")下,经过5 d的外源酸调控生物浸提,分别获得了84.5%、63.2%的Zn、Mn浸出效率;当Zn∶Mn∶Fe=0.4∶0.6∶2.0(物质的量比,即x=0.4)时,制备的纳米级Mn_(0.6)Zn_(0.4)Fe_2O_4性能最优,属纯相的立方尖晶石结构,颗粒分布均匀,饱和磁化强度(M_s)、剩余磁化强度(M_r)和矫顽力(H_c)分别为68.9 emu·g~(-1)、4.7 emu·g~(-1)和53.6 Oe,具有热稳定性和耐酸碱性,有望成为一种新型的水处理磁性材料. 相似文献
638.
639.
640.
公共危机状态下的管理,政府需要动员和统一调配多方面的资源,管理必须具有权威性,进行有效协调和快速行动,这就要求组建统一的领导指挥系统,通过综合协调部门和职能组织系统,最大限度地减少公共危机发生的可能性,或快速、有效地应对危机.最大限度地减少损失。指挥系统的建设公共危机给政府带来突发性、紧急性、危害性。急需要建立权威的、统一的领导指 相似文献