Collagen gene construction and evolution

Summary Collagen genes appear to have been assembled by the tandem repetition of homologous primary (9 base pair), secondary (54 base pair), and tertiary (702 base pair) modules. In vertebrate interstitial collagen genes many of the secondary modules are separated by introns, but in invertebrate collagen genes the non-coding sequences lie near the ends of supposed tertiary modules and are therefore about 702 (54×13) base pairs apart. The genes for vertebrate interstitial collagens (types I–III) seem to have been constructed by the tandem repetition of five tertiary modules, three of which were subsequently shortened by internal deletions. This shortening of the gene resulted in the non-integral relationship between the period of the fibrils and the length of the molecules of vertebrate collagens, and was therefore responsible for the mechanical properties of the completed product. Comparisons of the amino acid sequences of various collagens indicate that the main types of collagen evolved about 800–900 million years ago, a date that agrees well with the fossil record of primitive Metazoa.     

Positive anemotaxis by Varroa mites: responses to bee odour plumes and single clean‐air puffs

Abstract.The stimuli and mechanisms mediating host location and host choice by the bee mite, Varroa jacobsoni (Oudemans), are currently unknown. It is shown that Varroa can use single clean‐air puffs and bee‐odour plumes in a wind tunnel as directional cues. Varroa turned nearly straight upwind in response to single 0.1‐s puffs of clean air directed at 90° to the their anterior‐posterior axis. They turned significantly further to their left side (104°) than to their right (76°), but showed no difference in latency to initiation of the turns (means of 63.3 ms vs. 62.6 ms, respectively). They also followed bee‐odour plumes in a wind tunnel. When released in odour and control plumes mid‐way between the plume's origin and the downwind end of the tunnel, mites responding to bee‐odour walked upwind in, or along the edge of, the odour plume with 38% making contact with the odour delivery tube; mites in clean air did not walk upwind along the air stream, and none made contact with the air delivery tube. Walking speeds were not different between the bee‐odour and control groups (0.28 vs. 0.29 cm s^–1); there were also no differences in the turning rates (96.85 vs. 97.16 deg s^–1 and 388.08 vs. 379.18 deg cm^–1, respectively). Under all conditions, mites walked in a zigzag fashion.     

Behavioral responses of maleHeliothis armigera (Lepidoptera: Noctuidae) moths in a flight tunnel to combinations of components identified from female sex pheromone glands

Six compounds were identified from gland extracts of the cotton bollworm, Heliothis armigera(Hubner): (Z)-11-hexadecenal (Z11-16:Ald), (Z)-9-hexa-decenal (Z9-16:Ald), hexadecanal, (Z)-11-hexadecenol (Z11-16:OH), (Z)-7-hexadecenal (Z7-16:Ald), and (Z)-9-tetradecenal (Z9-14:Ald). Each of the compounds that were identified was examined for its ability to elicit sexual responses from male moths in a flight tunnel. Males flew upwind to Z11-16:Ald alone, but greater levels of copulatory responses were evoked with the addition of 2.5% Z9-16:Ald to the Z11-16:Ald. Addition of hexadecanal to the binary mixture had no effect in raising the behavioral response of the males in the flight tunnel. The effect of Z7-16:Ald on male flight depended on the loading. The addition of 1% of this component to 2 mg of the binary mixture reduced levels of copulatory response, but the same addition (1 %) to 10 g of the binary mixture increased copulatory response. The addition of 79-14:Ald or Z11-16:OH to the binary mixture reduced behavioral responses of males. High loadings of the binary mixture (200–2000 g) were better than a low loading (10 g) in eliciting response of males.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 2455-E, 1988 series.     

The relationship between the relative growth rate and nitrogen economy of alpine and lowland Poa species

This study investigates the nitrogen economy of six altitudinally contrasting Poa species which differ in their relative growth rate (R). Two alpine (Poa fawcettiae and P. costiniana), one sub-alpine (P. alpina)and three temperate lowland species (P. pratensis, P. campressa and P. trivialis) were grown hydroponically under identical conditions in a growth room. The low R exhibited by the alpine species was associated with lower plant organic nitrogen concentration (n_p) and lower nitrogen productivity (Π_p, amount of biomass accumulation per mol organic nitrogen and time). The differences in Π_p between the alpine and lowland species did not appear to be due to differences in the carbon concentration or the proportion of total plant organic nitrogen allocated to the leaves, stems or roots. Variations in Π_P were also not due to variations in photosynthetic nitrogen use efficiency (Ψ_N, the rate of photosynthesis per unit organic leaf nitrogen) or shoot or root respiration rates per unit organic nitrogen (Λ_SH and Λ_R, respectively) per se. Rather, the lower Λ_p in the alpine species was probably due to a combination of small variations in several of the parameters (e.g. slightly lower Ψ_N, slightly higher Λ_SH and Λ_R, and slightly higher proportions of total plant organic nitrogen allocated to the roots). The alpine species exhibited lower organic acid and mineral concentrations. However, no differences in whole-plant construction costs (grams of glucose needed to synthesize one gram of biomass) were observed between She alpine and lowland Poa species. The lack of sub-stantial differences in Ψ_N between the alpine and lowland species contrasts with the large differences in Ψ_N between slow- and fast-growing lowland species that have been reported in the literature. The reasons for the unusually high Ψ_N values exhibited by the alpine Poa species are discussed.     

Information analysis by the paper wasp,Polistes fuscatus,during nest construction (Hymenoptera,Vespidae)

Summary The building decision process of the paper wasp,Polistes fuscatus, was studied by 1) analyzing the search pattern of the wasps prior to the addition of pulp to different areas of the nest, 2) comparing the pulp addition needs of the cell chosen for lengthening to those of other cells in the nest, and 3) presenting the wasps with eight types of dichotomous building choices, which provided information about the relative influence of different building cues. Wasps conduct a hierarchical search prior to pulp addition, which means that they search the comb face and petiole disproportionately more often and more thoroughly than the comb back and sides. Once a particular nest area triggers closer scrutiny, comparisons are made with adjoining areas. The most needy location is then chosen based on nest cues. When lengthening a cell, the development of the brood and relative cell length have a strong influence on which cell is chosen at all times, while distance of the brood from the cell mouth becomes important during the later stages of brood development. The results indicate that there is no simple hierarchical weighting of cues. The decision process involves comparisons among multiple cues, which for the most part have an additive influence when variation in relative cue strength is considered.     

Promises and limits of an agency perspective in evolutionary developmental biology

An agent-based perspective in the study of complex systems is well established in diverse disciplines, yet is only beginning to be applied to evolutionary developmental biology. In this essay, we begin by defining agency and associated terminology formally. We then explore the assumptions and predictions of an agency perspective, apply these to select processes and key concept areas relevant to practitioners of evolutionary developmental biology, and consider the potential epistemic roles that an agency perspective might play in evo devo. Throughout, we discuss evidence supportive of agential dynamics in biological systems relevant to evo devo and explore where agency thinking may enrich the explanatory reach of research efforts in evolutionary developmental biology.     

山水林田湖草沙一体化保护和修复工程与景观生态学

我国山水林田湖草沙生命共同体及其保护和修复工程的理论研究和实践正逐渐开展,需要系统的学科理论支撑,景观生态学作为地理学和生态学的交叉科学,能够以其宏观空间理论和技术体系满足这一需求。本文将景观生态学作为山水林田湖草沙一体化保护和修复工程的支撑学科,首先,明确了山水林田湖草沙生命共同体是镶嵌的异质景观、具有景观的所有特征并遵循景观生态学原理;其次,阐述了景观生态建设理论如何应用于山水林田湖草沙一体化保护和修复工程的规划和评价;最后,总结景观生态建设研究的新趋势,提出待解决的理论和实践问题,并论述山水林田湖草沙一体化保护和修复工程如何为解决这些问题提供广阔的研究空间。景观生态学和山水林田湖草沙一体化保护和修复工程实践相结合,将为实现我国乃至全球生态、经济、社会可持续发展提供极为有效的途径。     

Flight responses in a wind tunnel of the parasitoid Microplitis croceipes to three spring and three summer host plants of Heliothis spp.

Flight responses of the parasitoid, Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) to two phenological stages of spring host plants (crimson clover, Trifolium incarnatum L., hairy vetch, Vicia villosa Corbiere, and cutleaf geranium, Geranium dissectum L.) and summer host plants (cotton, Gossypium hirsutum L., sorghum, Sorghum bicolor L., and soybean Glycine max (L.) Merr.) of Heliothis virescens (F.), were measured in a dual choice situation in a wind tunnel. Preflowering clover was more attractive than preflowering geranium, followed by preflowering vetch. Clover was preferred over geranium in flowering stages as well. No within species differences were detected for the two phenological stages. Preflowering and flowering cotton and soybean were preferred over preflowering and flowering sorghum. The findings could be important in pre-determining release sites for M. croceipes in the field.     

城乡建设用地关联对生态系统服务的影响——以洞庭湖地区为例

城乡建设用地数量及相互联系的变化是空间要素及结构演化的重要方面,深刻影响着生态环境质量和生态系统服务水平,研究城乡建设用地关联对生态系统服务的影响对国土空间高质量发展具有重要意义。以洞庭湖地区为研究对象,从土地利用关联视角出发,运用引力模型、InVEST模型、面板数据模型等方法,定量研究了城乡建设用地关联对生态系统服务的影响。结果表明：（1）洞庭湖地区城镇建设用地规模呈现上升趋势,农村居民点用地规模呈现下降趋势;（2）城乡建设用地关联强度呈不断增强趋势,且强关联网格以建成区为核心向周边扩展,低关联网格分布于远离建成区的地方;（3）生境质量和碳储量呈现下降趋势,食物供给则呈现上升趋势,各项生态系统服务价值具有显著的空间异质性;（4）城乡建设用地关联强度对生态系统服务具有负向影响,人口密度、GDP密度、夜间灯光、道路网络对生态系统服务也呈现负向影响,归一化差异植被指数与生态系统服务之间则存在显著的正相关。研究结果有助于了解关联视角下城乡建设用地对生态系统服务的影响机制,可以为制定合理的城乡空间发展战略提供科学依据。