摘要:

AbstractFruiting plants and frugivorous birds are known to interact. In endozoochory, frugivorous birds consume fruits and subsequently disperse seeds. It follows that fruit characteristics would have evolved to allow birds to consume fruits easily. However, one's benefit does not always mean the other's. There are several conflicts between fruiting plants and frugivorous birds in terms of nutrient content, retention time and number of seeds in a fecal pellet. Retention time of seeds in guts is particularly interesting. Longer retention time benefits plants directly by increasing seed dispersal distance but may involve indirect costs through birds' preference by reducing their consumption. To understand the exact role of seed dispersers in the reproductive success of fruiting plants, we should pay more attention to the possible conflicts between fruiting plants and frugivorous birds.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00139.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA new index that measures efficiency of dispersal traits is proposed to replace the “removal rate.” Escape from the mother plant is essential for survival of seeds. The percentage of escaped seed is therefore a good indicator of the efficiency of dispersal. However, seed trap experiments measure only an apparent rate of escaped seed (AES), because of contamination by seeds from other conspecific trees. If we assume that as many seeds of the experimental tree are carried to conspecific trees as travel in the reverse direction, AES is a good estimate of seeds escaped from both the mother and conspecific fruiting trees. This may be called the rate of effective escaped seeds (EES), because the seeds carried to conspecific trees have no more meaning for survival than those defecated beneath the mother tree. As an example, two fruiting traits, synchronous ripening and extended ripening, were compared for their efficiencies in terms of AES(? EES) at an urban botanical garden for two seasons. In the extended ripening species, about 80 percent of seeds were successfully dispersed away from the parent plant or conspecific plants for both seasons, but the percentages fluctuated, between 60 and 86, in the synchronous

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00140.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractNectar sugar composition, nectar secretion patterns, and effects of removal are compared in a natural hybrid experimentally supported (Lycium ciliatum × cestroides) and its parental species (L. ciliatumandL. cestroides). The nectar ofL. ciliatumandL. ciliatum×cestroidesis hexose dominant, but each taxon shows a distinctive pattern: more glucose than fructose in the former and the opposite pattern in the latter.L. cestroideshas sucrose‐rich nectar with more fructose than glucose. Both parental species show a similar sugar production pattern: the sugar content declines at the end of the flower lifetime due to nectar reabsorption. In contrast, in the hybrid, nectar secretion is continuous and there is no nectar reabsorption. Data obtained among the taxa are correlated with corolla depth: the deeper the corolla tube, the more diluted and the higher the volume of the nectar. Nectar production after removal is increased inL. cestroideswhereas it is not affected in the hybrid or inL. ciliatum. Chemical composition and response to removal relate the hybrid to the maternal parent (L. ciliat

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00141.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractA study of the pollination ecology ofPedicularis bracteosavar.paysonianawas carried out at four sites distributed over an 840m vertical transect in the montane‐subalpine ecotone of the Wyoming Rocky Mountains. Peak bloom ranged from June 30th at 2105m to August 2 at 2945m. Queens ofBombus flavifrons, B. kirbyellusandB. mixtuswere its major pollinators of a total of 363 individuals of nineBombusspecies collected foraging on the plants. The alpine tundra‐nesting queens ofB. kirbyelluswere the commonest pollinators at 2945m and were absent below 2675m.Bombus flavifrons, B. mixtusandB. ternariusspanned the entire transect. Measurement of 229 queen pollinator tongues (glossa‐prementum) indicated that mean tongue length increased with elevation but that each station encompassed a broad range of tongue lengths. With the longest tongue,B. kirbyellusforaged nototribically only;B. flavifronswas nototribic only at 2675m but both nototribic and sternotribically collecting pollen elsewhere. Species with shorter tongues were increasingly sternotribic at 2285–2675m and included more workers at these sites. Corbicular pollen loads from 141 pollinators indicated a distinctly lower pollen‐foraging constancy at 2105m than at higher elevations, but at all elevations pure loads were most frequent. It is suggested that the extension ofPedicularis bracteosavar.paysonianaover the entire montane‐subalpine ecotone has been facilitated both by its adaptability to differences in the physical environment and by its accommodation to related pollinators having distinct foragi

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00142.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPollinators and UV photos of flowers ofDuchesnea chrysanthaandD. indicaare discussed. The petals ofD. chrysanthareflect UV light strongly, while those ofD. indicahave a nectar guide appearing as a spot at the base of the petals that absorbs UV light. This is the same as inPotentillawhich is closely related taxonomically. InDuchesnea, we consider the presence of a nectar guide to be a derived character. The petals ofD. chrysanthaandD. indicaare distinguished by the presence or absence of nectar guides, but both species are pollinated mostly by the same kind of pollinators, which are commonly small polylectic insects. The main pollinators are four small bees (Andrena knuthi, A. minutula, Halictus aerarius, Lasioglossumsp.) and three syrphid flies (Paragus haemorrhous, Sphaerophoria macrogaster, S. philanthus). The total number of insect visitors inD. chrysanthawas 60 species, while inD. indicathere were 51. There was no significant difference in the visitors to the twoDuchesneaspecies, therefore, the adaptive meaning of the presence of nectar guides was not determined inDuchesnea.

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00143.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAnthecological observations on an orchidCremastra appendiculatavar.variabiliswere carried out during May and June, 1994, in Kobe, Japan. The pendulous, tube‐shaped flowers were visited by three species of bees and two of syrphid flies. Only queens of a long‐tongued bumble beeBombus diversus diversusreceived the pollinarium on one of their fore‐femora. The frequencies ofBombusflower visits were extremely low. A carpenter bee,Xylocopa appendiculata circumvolans, consistently robbed nectar by making a perforation at the flower

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper reports the first direct observation of reproductive processes of an emergent tree,Dryobalanops lanceolata(Dipterocarpaceae), and its interactions with pollinators and seed predators, using a canopy observation system built in Sarawak, Malaysia.D. lanceolataflowers were mostly pollinated by medium‐sized stingless bees (Trigonaspp., Apidae), and stigmas of all unbagged flowers received pollen grains. Ovaries did not develop without pollination. Abortion rate in the early stage of fruit development was 93% in fruits fertilized by natural pollinators. All the experimentally selfed ovaries were aborted at this stage. Despite the heavy abortion rate, the dry weight loss at this stage was only 17% of the total reproductive effort, because abortion occurred before active investment in fruits. Among the remaining fruits, 40% were lost to the primary seed predator,Mecysolobus crassus(Curculionidae). Such attacked fruits were also selectively aborted at the middle stage of fruit maturation. Final germinating fruits, which were 3.6% of the total number of flowers, got 47% of the total reproductive effor

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe floral biology and pollination ofMagnolia praecocissimavar.borealis, a tall tree blooming before leaf‐emergence in early spring, were studied in Hokkaido, northern Japan. The flower is protogynous, and each flower lasts about 9 days without closing its petals. The mean duration of the female‐stage and the male‐stage flowers is about 4 and 4–5 days, respectively. The flowering period of an individual tree can be divided into three sexual phases: female, bisexual, and male. Manual pollination and bagging experiments showed that the plants were self‐compatible and that pollinators were necessary for a flower to produce seeds. It was observed that several species of small pollen‐foraging beetles were the most effective pollinators. The male‐stage flowers offered pollen as a reward, while the female‐stage flowers offered no reward; it is likely that the non‐rewarding female‐stage flowers mimic the rewarding male‐stage flowers. The pollination syndrome ofMagnolia praecocissimavar.borealisdiffers from North AmericanMagnoliaspecies in its long‐lasting flowers, is no closure of flowers at night, and in lack of f

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAllozyme variation was analyzed in 180 individuals of Yushan cane from adjacent sun and shade microhabitats from three localities on Mt. Hohuan in Taiwan. Significant genetic differentiation according to microhabitat was found for both single and multi‐locus comparisons. Moreover, sun sub‐populations from different localities clustered together in a neighbor‐joining tree based on isozyme genetic distances, as did shade sub‐populations. These data not only imply significant local adaptation for different habitats in phenotypically plastic Yushan cane, but also suggest that diversifying selection is acting on allozyme loci or closely linked

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPlastic responses of 12 morphological and life history traits to different nutrient and light intensity gradients were studied in five populations ofOxalis corniculata, a clonal perennial with creeping horizontal runners. This species comprises two floral morphs, homostyled and long‐styled, with different breeding systems. In controlled nutrient and light intensity experiments, 98 of 120 traits exhibited significant plastic responses in one‐way ANOVA; significant population × treatment interaction terms in two‐way ANOVA were found for 16 of 24 traits. Marked growth responses were noted in the plants grown along different environmental gradients. Reduced light availability decreased reproductive allocation and enhanced vertical and horizontal stems. To investigate the plastic responses of homostyled and long‐styled populations in further detail, patterns and amounts of plastic responses across 12 traits were also quantified. Significantly different overall amounts of plastic responses among the populations were found along the nutrient gradient. In addition, we also evaluated the foraging ability of these populations in terms of spacer length and branching intensity. There were three different types of foraging behaviors along the light intensity gradient. Homostyled populations generally showed small amounts of plastic response and foraging ability; in contrast, long‐styled populations tended to exhibit larger amounts of plastic response and greater foragi

ISSN:0913-557X    

DOI:10.1111/j.1442-1984.1996.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY