Effect of 9.6-GHz pulsed microwaves on the orb web spinning ability of the cross spider (Araneus diadematus)

Eight cross spiders (Araneus diadematus) were exposed overnight (16 h) during web-building activity to pulsed 9.6-GHz microwaves at average power densities of 10, 1, and 0.1 mW/cm2 (estimated SARs 40, 4, and 0.4 mW/g). Under these conditions, 9.6-GHz pulsed microwaves did not affect the web-spinning ability of the cross spider.     

Evolution and development: Past, present, and future

The paper tries to set right certain ideas about the history of evolutionary developmental biology. The main point is, that we had to enface the dominance of a comparative approach towards evolutionary developmental biology before 1900, which even later on was effective in Russia, for example, till the 1930s. The problem of the experimentalist approach set against this tradition was and is that there is no concept of gestalt that may allow to integrate the former comparative views and the modern mechanistic interpretations. We argue, that it would be wrong just to describe the comparative tradition as being outdated, as it may allow to get the framework for a dynamical concept of Gestalt that may integrate the ideas of morphogenesis and pattern formation worked out in evo-devo recently.     

锈翅蚁蛉(脉翅目:蚁蛉科)的发育生物学研究

锈翅蚁蛉为全变态类昆虫,在贵州省一年发生1代,11月下旬开始越冬,各龄幼虫均可越冬,次年3月苏醒.在室内饲养条件下,卵期13 d±0.56 d,幼虫期63.58 d±1.81d,蛹期26.35 d±1.14 d,成虫期20 d± 1.06 d.结合野外调查和室内饲养,详细描述了锈翅蚁蛉各虫态的形态特征,幼虫的筑穴、捕食、蜕皮、化蛹、羽化以及成虫的捕食、交配等行为习性.     

Do stabilimenta in orb webs attract prey or defend spiders?

Orb-weaving spiders are ideal organisms for the study of conflictbetween behavioral investments in foraging and defense becausetheir webs provide physical manifestations of those investments.We examined the impact of including stabilimenta, designs ofbright-white noncapture silk, at the center of orb webs forforaging and defense in Argiope aurantia. Our findings suggestthat stabilimentum building is a defensive behavior, supportingthe "web advertisement" hypothesis that the high visibilityof stabilimenta can prevent birds from flying through webs.Yet, spiders often do not include stabilimenta in their webs,indicating that a serious cost is associated with them. We alsoshow, through comparison of paired webs with and without stabilimenta,that stabilimenta reduce the prey capture success of spidersby almost 30%. This demonstrates the potential impact that defensivebehaviors of spiders can have on their foraging success andsuggests that much of the variation in stabilimenta may be accountedfor by a cost—benefit trade-off made when including stabilimentain webs.     

Memory of distances and directions moved as cues during temporary spiral construction in the spiderLeucauge mariana (Araneae: Araneidae)

The spider Leucauge marianaprobably uses the presence of temporary spiral (TSP) lines already in place to determine sites of attachment of currently produced loops of temporary spiral, but less rigidly than has been previously supposed for orb weavers. Memory of distances and directions traveled recently to and from TSP lines is implicated by the fact that adjustments to experimental and natural discontinuities in previous TSP lines occur gradually rather than being abrupt. Distances and directions traveled along both radii and previous TSP lines correlate with relative amounts of adjustment. Body size may also be used as a reference measure, but not in the simple, inflexible way suggested by R. W. G. Hingston (A Naturalist in Himalaya,Small, Maynard, Boston, 1920). Tensions on radii are not used as cues in any simple way, and may not be used at all, since experimental changes in tensions produced effects consistent with resulting changes in thread positions but inconsistent with tension differences.     

Reduced Aggressive Behavior: A Benefit of Silk-Spinning in the Parsnip Webworm, Depressaria pastinacella (Lepidoptera: Oecophoridae)

The parsnip webworm, Depressaria pastinacella, spins a silken web within the umbels of its host plant, the wild parsnip Pastinaca sativa, and aggressively defends this web against conspecifics. We first established experimentally that the number of aggressive interactions between caterpillars with their webs removed was significantly higher than for webworms with intact webs. In order to determine whether web-spinning acts to divide food resources and reduce aggressive interactions, we measured relative weight gain and total silk production of parsnip webworms isolated from one another, grouped together with webbing undisturbed, and grouped together with webbing removed daily. Parsnip webworms isolated from one another and therefore unable to engage in aggressive interactions attained the highest pupal weights and spun the smallest amount of silk; caterpillars with webs removed daily and therefore with frequent aggressive interactions until territories were reestablished had the lowest pupal weights and spun the greatest quantity of silk. Our findings indicate that, for the parsnip webworm, constructing a silken web reduces aggressive encounters among conspecifics.     

Reproduction,physical growth and behavioral development in slow loris (Nycticebus coucang,Lorisidae)

Reproduction of slow loris maintained in in- and outdoor enclosures in the natural day-night-cycle of southern Germany seems to be seasonally dependant. Mating occurs during summer, delivery of offspring during winter. Gestation length as determined from mid-estrus was 186–187 days. Copulation takes place over two to five consecutive days during estrus. Litter size for each of the recorded births was one. Lactation lasts for five to seven months. Sexual maturity is reached at about 1 1/2 to 2 years. Physical growth and the first appearance of main locomotor, behavioral and vocal patterns are described until nutritive weaning. With regard to acoustic structures, the vocal repertoire of newborn slow loris is quite similar to that of adults. During ontogeny main changes are discerned in the temporal pattern and pitch frequency of vocalizations and in their use. Results are compared with other primates.     

Correlation of acoustic and visual signals in the cichlid fish, <Emphasis Type="Italic">Tramitichromis intermedius</Emphasis>

We investigated acoustic and visual communication concurrently in wild caught adult and captive-born, first generation offspring of the East African Rift Lake cichlid fish Tramitichromis intermedius. Only males emit sound during courtship. Sound production is always accompanied by quivering, but quiver behavior is not always accompanied by sound. This separation of quivering and sound supports the hypothesis that sound production is intentional serving a communicative role. As spawning nears, both sound production and quiver behavior increase. In terms of the ontogeny of sound production, the first observation of courtship occurs just days before the first spawning event and the first sound emission accompanies the first courtship activity. The accompaniment of quivering with sound as well as the escalation of the two behaviors with the approach of spawning follows similar patterns in wild caught and captive-born males. The tight correlation between behavior and sound production in both groups indicates their simultaneous performance plays an important role in reproduction. It is probable that the ability to produce sound and perform quiver behavior at the same time may be a measure of mate quality.     

棒络新妇和悦目金蛛拖丝超微结构与力学行为

采用SEM对棒络新妇Nephila clavata腹部向上和向下在水平纱窗上爬行时纺出的拖丝、悦目金蛛Argiope amoena捕食拖丝与垂直向下缓慢纺出的拖丝及其圆网的铆钉丝进行了超微结构观察,采用电子单纤强力仪对棒络新妇拖丝与悦目金蛛圆网铆钉丝进行了力学拉伸试验.结果 表明棒络新妇和悦目金蛛拖丝均呈现出一至多根细丝纤维的多样化超微结构特征,其中悦目金蛛圆网铆钉丝还呈现出"S"形似弹簧的结构.两种蜘蛛丝的力学行为和性能与各自的功能要求相一致.蜘蛛能调节拖丝的超微结构、纤维组成和直径大小以适应其在不同环境条件下对力学性能和功能的瞬时需要.研究结果有助于拓宽和加深人们对蜘蛛丝超微结构、力学性能与生物学功能之间关系的认识和理解.     

The conceptual framework of evolutionary morphology in the studies of Ernst Haeckel and Fritz Müller

In his Gastraea studies Ernst Haeckel characterized the initial stages of the animal embryo, describing complete and incomplete cleavages in various groups, until the gastrula stage. Thereby, he was able to point out various degrees of developmental diversification in these initial stages of development. As the functional meaning of such cleavages was not clear however, it was difficult to argue about putative functional adaptations. Information about the consequences for tissue formation initiated in this primary phase of development was simply lacking. Haeckel could only provide a vague picture of a highly diversified but systematically inconsistent distribution of various types of early embryogenesis. Thereby he discusses phylogenetically preserved (palingenetic) stages of development and adaptations to certain specific situations of the embryo (cenogenesis). To decide whether such types, in the initial stages of embryogenesis, are ceno- or phaenogenetic is quite difficult. Reference to the highly diversified distribution of certain types within specific groups is an indication that there is no strict adaptive pressure on these early parts of embryonic development. This makes it possible to formulate – as Haeckel did it – the idea, that in these initial phases palingenetic attributes are dominant. Thus, he tried to use these early phases of development for the classification of larger systematic units. The result is a concept of an evolutionary morphology, that was, however, never elaborated in detail by Haeckel. Therefore, it remained without effect for evolutionary biology. On the contrary, following the Darwinian approach towards a comparative analysis of embryogenesis, Fritz Müller presented a series of examples for a comparative developmental biology that allowed one to interpret certain morphological characteristics as the outcome of common evolutionary histories within different species. For various crustacean species, he was able to demonstrate that certain attributes are not to be characterized as functionally relevant adaptations, but are evolutionarily inherited.