排序方式: 共有40条查询结果,搜索用时 15 毫秒
1.
Counts of Steller sea lion ( Eumetopias jubatus ) pups and non-pups (adults and juveniles) from aerial photographs of rookeries at Año Nuevo Island between 1990 and 1993 were significantly higher than those made on the ground. Based on regression of natural logs of photographic counts versus year, the number of pups declined at a rate of −0.099yr while non-pup numbers declined at −0.315/yr. Examination of ground count data for the same period revealed a significant decline in non-pups (−0.139/yr), but no trend was detected in the ground counts of pups. The regression coefficients from photographic and ground counts of non-pups did not differ significantly. Power analyses using the program TRENDS indicated that detectable rates of change in abundance from four annual surveys were much lower for counts of pups than counts of non-pups where sampling precision was based on fits to linear models. 相似文献
2.
Male moths locate conspecific females by pheromone‐induced upwind flight maintained by detecting a visual flow, termed optomotor anemotaxis. Their behavioural pattern is characterized by an upwind surge in response to a pheromone stimulus and crosswind casting after odour loss, which is considered to be reset and restarted on receipt of another pheromone pulse. However, pheromone‐stimulated males of the potato tuberworm moth Phthorimaea operculella exhibit a series of short and straight intermittent flights, or hops, when moving upwind. It is unclear whether they navigate by employing the same behavioural pattern and wind detection mechanism as that used by flying moths. To analyze odour‐modulated anemotaxis in male potato tuberworm moths, a flat wind tunnel is constructed to give regular odour stimuli to an insect regardless of its location. Moths are subjected to pheromone pulses of different frequencies to test whether they show a behavioural pattern that is reset and restarted by a pheromone pulse. Moths on the ground are also subjected to crosswind shear to examine their detection of wind direction. Path analyses reveal that males surge upwind when they receive a pheromone pulse and exhibit casting by successive hops when they lose odour. This behavioural pattern appears to be similar to that of flying moths. When the direction of the airflow is switched orthogonally, males adjust their course angle accordingly when they are on the ground. It is suggested that, instead of optomotor anemotaxis, this ‘aim‐then‐shoot’ system aids the detection of wind direction, possibly by mechanosensory means. 相似文献
3.
KOUKI ONO MASAHIRO OKIHASHI HIROSHI INUI KAZUTAKA MIYATAKE SHOZABURO KITAOKA YOSHIHISA NAKANO 《The Journal of eukaryotic microbiology》1994,41(6):536-539
Isocitrate lyase was purified to homogeneity from ethanol-grown Euglena gracilis. The specific activity was 0.26 μmol/min/mg protein. The molecular mass of the enzyme was calculated to be 380 kDa by gel filtration on a Superose 6 column. The subunit molecular mass of the enzyme was 116 kDa as determined by SDS-polyacrylamide gel electrophoresis. These results showed that the native form of this enzyme was a trimer composed of three identical subunits. The pH optimum for cleavage and condensation reactions was 6.5 and 7.0, respectively. The Km values for isocitrate, glyoxylate and succinate were 3.8, 1.3 and 7.7 mM, respectively. Isocitrate lyase absolutely required Mg for enzymatic activity. This is the first report of the purification of isocitrate lyase to homogeneity from Euglena gracilis. 相似文献
4.
HISASHI OKAMOTO AKIKO MIZUNO KIYOSHI KATOU YOSHINA ONO YASUKO MATSUMURA HIROSHI KOJIMA 《Plant, cell & environment》1984,7(2):139-147
Abstract A new experimental system was devised for the simultaneous measurement of elongation rate and the activity of the spatially separate electrogenic ion pumps of a hypocotyl segment excised from a seedling of Vigna unguiculata L. Walp. under enforced intra-organ perfusion by artificial solutions. The pathway of the perfusion medium was apoplastic space, including xylem vessels as main routes. The elongation rate of the segment was highly dependent on the perfusion pressure applied. It was possible to increase the growth rate under pressurized perfusion by 10-30 times as much as that without perfusion. Elongation rate was also dependent on respiration under perfusion, being retarded reversibly by anoxia a few minutes after the activities of the electrogenic ion pumps were stopped. Perfusion pressure had a little influence on the membrane potential (Vpx) below a breakdown level (c. 130 kPa). Perfusion of mannitol or sorbitol solution of appropriate concentration reduced the elongation rate reversibly. 相似文献
5.
Kazuhisa YAMASAKI Jun‐ichi TAKAHASHI Masato ONO Koji TSUCHIDA 《Entomological Science》2011,14(4):383-386
In Polistes paper wasps, haploid early males can mate with early emerging females and leave viable offspring. In contrast, diploid early males are eventually sterile because they contribute triploid offspring via diploid sperm. Clarifying the ploidy of early males is important for determining whether early male production is a reproductive strategy for the species. We examined the mating behavior and the ploidy of early males in the Japanese paper wasp, Polistes rothneyi iwatai van der Vecht. Thirteen early males from four colonies were all diploid. Two of the nine early males (22.2%) attempted to mate with females, but only one individual (11.1%) was successful (the female's spermatheca contained spermatozoa). These results suggest that although most early males of P. rothneyi iwatai do not produce offspring, their mating may be linked to the occasional production of triploid females. 相似文献
6.
7.
The female Truljalia hibinonis ingests metanotal secretions of the male during copulation. The effect of ingestion on oviposition behavior was compared between three female groups: females that copulated once with an intact male (a male that had not been manipulated; M group); females that copulated once with a male from which most of the metanotal secretion had been removed (NO group); and females that copulated once with an intact male followed by being artificially supplied with metanotal secretion three times (MS group). There were no obvious differences in female fecundity across the three groups. However, within the MS group, intake of an optimal amount of metanotal secretion increased the number of eggs laid. This effect appeared quickly after ingestion and was most effective on the first bout (eggs laid during the first few days after copulation) after ingestion of the metanotal secretion. In contrast, the number of eggs laid had a negative correlation with the amount of metanotal secretion ingested when the amount exceeded the optimal in this experimental arrangement. 相似文献
8.
日本的庭院文化经过长时间发展,已形成独特的景观空间语言。这些空间语言由庭园、公园、广场等城市外部空间传承,而我们需要静下心来理解这掺杂着思想和时代背景的特殊语言体系。日本的景观教育,通过以下课程设置,将空间的语言体系传授给学生们:1)通过测量掌握设计语言的基础,学生通过尺子测量传统空间和现代空间,获得相应的空间感。近年来也通过3D测量技术,掌握更加精细的尺度感。2)材料使日本特有的设计语言更加丰富多变,通过实际接触石材和植物,体验管理和施工,加深学生对材料的理解。3)在学习和实践的基础上,进行与国际和社会接轨的设计。面对当下多领域融合的社会课题,组织建筑、规划、土木等学科的学生们进行展览和交流,并开展相应的实践训练 相似文献
9.
JARI KOUKI 《Freshwater Biology》1991,26(3):347-353
SUMMARY. 1. The effect of the water-lily beetle, Galerucella (= Pyrrhalta ) nymphaeae (L.), (Coleoptera, Chrysomelidae), on the leaf production and leaf longevity of the yellow water-lily, Nuphar lutea (= N. luteum ) (L.) Sibth. & Sm., was studied experimentally in southern Finland during one growth season.
2. Twelve cages, each containing a single rosette of the water-lily, were established in the lake during May. Two treatments were randomly applied to cages: (i) control (herbivory not allowed), and (ii) fifty beetles added at the beginning of the season. Leaves were marked individually and the production of new leaves was followed until October.
3. In both treatments the production of floating leaves continued until the end of August but declined towards the end of summer. Herbivory did not affect the number of leaves produced, i.e. the plants did not compensate for the loss of leaves.
4. Leaf longevity was reduced dramatically (up to —60%) when herbivores were present. Leaves that emerged during the most intense period of larval growth had a life-span one-third of that of the control group. 相似文献
2. Twelve cages, each containing a single rosette of the water-lily, were established in the lake during May. Two treatments were randomly applied to cages: (i) control (herbivory not allowed), and (ii) fifty beetles added at the beginning of the season. Leaves were marked individually and the production of new leaves was followed until October.
3. In both treatments the production of floating leaves continued until the end of August but declined towards the end of summer. Herbivory did not affect the number of leaves produced, i.e. the plants did not compensate for the loss of leaves.
4. Leaf longevity was reduced dramatically (up to —60%) when herbivores were present. Leaves that emerged during the most intense period of larval growth had a life-span one-third of that of the control group. 相似文献
10.
Y. ONO T. DOI H. IKEDA M. BABA M. TAKEISHI M. IZAWA T. I. WAMOTO † 《African Journal of Ecology》1988,26(1):33-49