High fruit sets in a rewardless orchid: a case study of obligate agamospermy in Habenaria

2018 ◽  
Vol 66 (2) ◽  
pp. 144 ◽  
Author(s):  
Wenliu Zhang ◽  
Jiangyun Gao
Keyword(s):  
Fruit Set ◽  
High Fecundity ◽  
Orchid Seed ◽  
Pollinator Service ◽  
Floral Visitors ◽  
Different Populations ◽  
Study Sites ◽  
Germination Experiments ◽  
Rewardless Orchid ◽  
The Cost

Low fruit set and pollination limitation are common characteristics of non-autogamous orchids, especially in rewardless species. The flowers of many Habenaria species are often characterised by long spurs and are mostly pollinated by long-tongued hawkmoths or butterflies. Unlike the flowers of other Habenaria species, the flowers of Habenaria malintana (Blanco) Merr. have very short spurs with no nectar or scent; however, this species is able to maintain high fecundity in south-west China. Breeding system experiments suggested that H. malintana is an obligate agamospermous orchid. Seed set did not need to be triggered by pollen grain deposition on stigmas, and ~100% fruit set was found in different populations and years. In pollen germination experiments, hand-deposited pollen failed to germinate on stigmas. The flowers of H. malintana failed to attract any pollinators, as we did not observe any floral visitors, and no pollinia removal or deposition occurred in both 2013 and 2014 at two study sites. These results strongly suggested that H. malintana has completely abandoned sexual reproduction and has adopted obligate agamospermy to achieve high reproductive output. We suggest that this strategy may have evolved to provide reproductive assurance and reduce the cost of flowers in response to unreliable pollinator service.

scholarly journals The cost of associating with males for Bornean and Sumatran female orangutans: a hidden form of sexual conflict?

2020 ◽  
Vol 75 (1) ◽  
Author(s):  
Julia A. Kunz ◽  
Guilhem J. Duvot ◽  
Maria A. van Noordwijk ◽  
Erik P. Willems ◽  
Manuela Townsend ◽  
...  
Keyword(s):  
Sexual Conflict ◽  
Sexual Coercion ◽  
High Association ◽  
Sexual Swellings ◽  
Fecal Cortisol ◽  
Habitat Productivity ◽  
Pongo Pygmaeus Wurmbii ◽  
Males And Females ◽  
Study Sites ◽  
The Cost

Abstract Sexual coercion, in the form of forced copulations, is relatively frequently observed in orangutans and generally attributed to their semi-solitary lifestyle. High ecological costs of association for females may be responsible for this lifestyle and may have prevented the evolution of morphological fertility indicators (e.g., sexual swellings), which would attract (male) associates. Therefore, sexual conflict may arise not only about mating per se but also about associations, because males may benefit from associations with females to monitor their reproductive state and attempt to monopolize their sexual activities. Here, we evaluate association patterns and costs for females when associating with both males and females of two different orangutan species at two study sites: Suaq, Sumatra (Pongo abelii), and Tuanan, Borneo (Pongo pygmaeus wurmbii). Female association frequency with both males and females was higher in the Sumatran population, living in more productive habitat. Accordingly, we found that the cost of association, in terms of reduced feeding to moving ratio and increased time being active, is higher in the less sociable Bornean population. Males generally initiated and maintained such costly associations with females, and prolonged associations with males led to increased female fecal cortisol metabolite (FCM) levels at Tuanan, the Bornean population. We conclude that male-maintained associations are an expression of sexual conflict in orangutans, at least at Tuanan. For females, this cost of association may be responsible for the lack of sexual signaling, while needing to confuse paternity. Significance statement Socioecological theory predicts a trade-off between the benefits of sociality and the ecological costs of increased feeding competition. Orangutans’ semi-solitary lifestyle has been attributed to the combination of high association costs and low predation risk. Previous work revealed a positive correlation between association frequencies and habitat productivity, but did not measure the costs of association. In this comparative study, we show that females likely incur costs from involuntary, male-maintained associations, especially when they last for several days and particularly in the population characterized by lower association frequencies. Association maintenance therefore qualifies as another expression of sexual conflict in orangutans, and especially prolonged, male-maintained associations may qualify as an indirect form of sexual coercion.

Differentiation of reproductive traits between central and peripheral populations of Allium wallichii Kunth

2021 ◽  
Author(s):  
Hanqing Tang ◽  
Demei Hu ◽  
Chao Zhang ◽  
Juan Yang ◽  
Mengda Xiang ◽  
...  
Keyword(s):  
Pollen Germination ◽  
Plant Density ◽  
Peripheral Populations ◽  
Seed Setting ◽  
Peripheral Population ◽  
Reproductive Characteristics ◽  
Central Population ◽  
Floral Visitors ◽  
Different Populations ◽  
Seed Setting Rate

The differentiation of reproductive characteristics not only exists between different populations, but also may exist within populations. In this work, the differences between the central and peripheral populations were experimentally compared and analyzed in terms of biodiversity index, plant traits, anthesis, pollen germination, floral visitors, seed setting rate, and ploidy. The results showed that the diversity and richness of other plant species, in the central population were significantly lower than those in the peripheral population, but the plant density was much higher than in the peripheral population. The plant anatomical traits, anthesis, pollen germination, floral visitors, seed setting rate, and ploidy were significantly different between central population and peripheral populations. The term increasing rate (IR) is proposed as a means of comparing morphologies in different organs. IR differences in vegetative characteristics were more stable, while those in reproductive characteristics differed significantly. For the central population, the effect of the intraspecific reproductive competition and pollinator selection on plants may significant, and morphology was differentiated in terms of reproductive characteristics. Plants in the peripheral populations were visited by many more pollinators than in the central population, and all pollinators visited infrequently. The reproductive characteristics of plants in the peripheral populations may therefore only be weakly affected by pollinator selection. The reproductive characteristics of plants in the peripheral population may weakly affected by the selection of pollinators and the variation was small. In conclusion, morphological differentiation among the different populations was associated with differences in vegetative and reproductive characteristics.

scholarly journals Breeding biology and distyly in Palicourea rigida H. B. & K. (Rubiaceae) in the Cerrados of Central Brazil

2010 ◽  
Vol 24 (3) ◽  
pp. 686-696 ◽  
Author(s):  
Adriana de Oliveira Machado ◽  
Ana Palmira Silva ◽  
Helder Consolaro ◽  
Mariluza A. Granja e Barros ◽  
Paulo Eugênio Oliveira
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Pollen Grains ◽  
Floral Biology ◽  
Nectar Production ◽  
Central Brazil ◽  
Palicourea Rigida ◽  
Floral Visitors ◽  
Compatible Pollen ◽  
Incompatibility Reactions

Distyly is a floral polymorphism more common among the Rubiaceae than in any other angiosperm group. Palicourea rigida is a typically distylous species of the Rubiaceae widely distributed in the Brazilian Cerrados. This work aimed to study the floral biology and breeding system of P. rigida in order to verify if there wasasymmetry between floral morphs. The work was carried out at Fazenda Água Limpa, Brasília-DF, from 1993 to 1995; and at Serra Caldas Novas State Park-Goias and in Clube Caça e Pesca Itororó de Uberlândia-Minas Gerais in 2005 and 2006. Density, height and pin/thrum ratio were assessed for flowering individuals in all areas. Plants were investigated for differences in floral morphology, nectar production, reproductive success and site of self incompatibility reactions. Blooming period was long and concentrated during the rains. Flowers were clearly distylous and with reciprocal herkogamy. They produced nectar and lasted for a single day. In spite of differences in density and height, populations were mostly isoplethic. Nectar production varied in volume and concentration but the differences could not be associated with floral morphs. The species is self-incompatible but reproductive success was always high and independent of floral morphs. There were differences in the site of incompatibility barriers between floral morphs, which were similar to those observed for other Rubiaceae. The main floral visitors and pollinators were the hummingbirds Colibri serrirostris and Eupetomena macroura. High fruit-set indicates that the pollinators transported enough compatible pollen grains between floral morphs, despite their territorial behavior.

scholarly journals Wind and insect pollination (ambophily) of Mallotus spp. (Euphorbiaceae) in tropical and temperate forests

2013 ◽  
Vol 61 (1) ◽  
pp. 60 ◽  
Author(s):  
Eri Yamasaki ◽  
Shoko Sakai
Keyword(s):  
Population Density ◽  
Temperate Forest ◽  
Fruit Set ◽  
Forest Succession ◽  
Airborne Pollen ◽  
Flowering Plants ◽  
Insect Pollination ◽  
Pioneer Tree ◽  
Pioneer Plants ◽  
Study Sites

Relatively few flowering plants show ambophily (pollination by both wind and insects), and whether and when ambophily is advantageous has not been studied well. In the present study, we report ambophily in two dioecious pioneer tree species, Mallotus japonicus Müll.Arg. in a temperate forest of Japan, and Mallotus wrayi King ex Hook.f. in a tropical forest of Borneo, and discuss the conditions that contribute to the maintenance of ambophily. Both species are pollinated by wind because they set fruits even when flower visitors were excluded and because substantial amounts of airborne pollen reached female trees. Insects may also contribute to fruit set, because insects with body pollen visited female inflorescences. Because M. japonicus and M. wrayi exhibit floral characteristics that are adapted to both wind and insect pollination, ambophily may be actively maintained in the two species at the study sites and perhaps elsewhere. Whereas previous studies have indicated that ambophily is advantageous for pioneer plants because of changing wind conditions during forest succession, our preliminary data suggest that changes in population density also contribute to the maintenance of ambophily in M. japonicus.

scholarly journals On the Optimal Allocation of Students and Resources in a System of Higher Education

2008 ◽  
Vol 8 (1) ◽  
Author(s):  
James M Sallee ◽  
Alexandra M Resch ◽  
Paul N Courant
Keyword(s):  
Higher Education ◽  
Economies Of Scale ◽  
Optimal Allocation ◽  
Education Quality ◽  
Fixed Cost ◽  
Congestion Costs ◽  
Tiered System ◽  
Different Populations ◽  
Student Ability ◽  
The Cost

Abstract We model the social planner's decision to establish universities and populate them with students and resources, given a distribution of student ability and a limited pool of resources for higher education. If student ability and school resources are complements, and if there is a fixed cost to establishing a school, then the optimal allocation will involve a tiered system of higher education that sorts students by ability. In contrast to previous research, we show this tiered system is optimal even in the absence of peer effects. In considering where to locate students, the planner balances the benefit of providing students with more resources against the congestion costs of overcrowding schools. Nearly identical students who are close to the margin of entry to a higher or lower tier will experience discrete gaps in education quality. In considering how many universities to establish, the planner will balance the value of more precise tailoring against the cost of establishing additional schools. The planner's inability to perfectly tailor education quality will result in both winners and losers. Our model also makes predictions about how university systems that serve different populations should vary. Larger systems will produce more per dollar of expenditures and more education per student, due to economies of scale.

scholarly journals Reproductive Biology of a Medicinal Orchid Satyarium Nepalense (Orchidaceae) in the Nepalese Himalayas

2020 ◽  
pp. 15-18
Author(s):  
Babu Ram Paudel ◽  
Brihaspati Poudel
Keyword(s):  
Natural History ◽  
Spatial Variation ◽  
Reproductive Biology ◽  
Important Implication ◽  
Fruit Set ◽  
Medicinal Uses ◽  
Floral Visitors ◽  
Medicinal Orchid ◽  
Two Populations ◽  
Very High

Satyrium nepalense is a terrestrial medicinal orchid of the Himalayas. Although, the ecology and medicinal uses of this orchid is well known, little is known about its reproductive mechanism. In this study, we explored the natural history and reproductive biology of S. nepalense and tested their potential spatial variation. We observed the floral visitors and natural fruit set of S. nepalense at its two populations. We found that, despite the presence of outcrossing features, this orchid did not receive any diurnal floral visitors. The natural fruit set was very high (>90.0%) at both the sites, suggesting the possibility of autonomous selfing. This finding may have important implication for the further study to explore how autonomous selfing evolves in a member of the predominately outcrossing genus. Moreover, the finding of this study provides important insight to develop efficient protocol for its conservation.

scholarly journals Implementation of A Structured Emergency Nursing Framework Results in Significant Cost Benefit

2021 ◽  
Author(s):  
Kate Curtis ◽  
Prabhu Sivabalan ◽  
David S. Bedford ◽  
Julie Considine ◽  
Alfa D’Amato ◽  
...  
Keyword(s):  
Cost Benefit ◽  
Emergency Nursing ◽  
Net Benefit ◽  
Patient Deterioration ◽  
South Wales ◽  
Financial Benefits ◽  
Implementation Costs ◽  
Study Sites ◽  
Cost Implications ◽  
The Cost

Abstract Background Patients are at risk of deterioration on discharge from an emergency department (ED) to a ward, particularly in the first 72 hours. The implementation of a structured emergency nursing framework (HIRAID) in regional New South Wales (NSW), Australia, resulted in a 50% reduction of clinical deterioration related to emergency nursing care. To date the cost implications of this are unknown. The aim of this study was to determine any net financial benefits arising from the implementation of the HIRAID emergency nursing framework. Methods This retrospective cohort study was conducted between March 2018 and February 2019 across two hospitals in regional NSW, Australia. Costs associated with the implementation of HIRAID at the study sites were calculated using an estimate of initial HIRAID implementation costs (AUD) ($492,917) and ongoing HIRAID implementation costs ($134,077). Equivalent savings (i.e. in less patient deterioration) were calculated using projected estimates of ED admission and patient deterioration episodes via OLS regression with confidence intervals for incremental additional deterioration costs per episode used as the basis for scenario analysis. Results The HIRAID-equivalent savings exceed the costs of implementation under all scenarios (Conservative, Expected and Optimistic). The estimated preliminary savings to the study sites was $1,914,252 with a payback period of 75 days. Conservative projections estimated a net benefit of $1,813,760 per annum by 2022-23. The state-wide projected equivalent savings benefits of HIRAID equalled $227,585,008 per annum, by 2022-23. Conclusions The implementation of HIRAID reduced costs associated with resources consumed from patient deterioration episodes. The HIRAID-equivalent savings exceed the costs of implementation across a range of scenarios, and upscaling would result in significant patient and cost benefit.

Nematode assemblages associated with the parthenogenetic lizard Ameivula nativo in six restinga areas along the eastern coast of Brazil

2017 ◽  
Vol 92 (5) ◽  
pp. 554-562 ◽  
Author(s):  
V.A. Menezes ◽  
J.C. Mascarenhas ◽  
D. Vrcibradic ◽  
C.F.D. Rocha
Keyword(s):  
Nematode Species ◽  
Eastern Coast ◽  
Geographical Distance ◽  
Intensity Of Infection ◽  
Pooled Data ◽  
Eastern Brazil ◽  
Low Diversity ◽  
Different Populations ◽  
Study Sites ◽  
Nematode Fauna

AbstractWe surveyed the nematode assemblages associated with populations of the parthenogenetic whiptail lizard Ameivula nativo from six coastal restinga areas in eastern Brazil: Setiba, Comboios and Guriri (State of Espirito Santo) and Guaratiba, Prado and Maraú (State of Bahia). A total of five nematode species (Physaloptera retusa, Physalopteroides venancioi, Skrjabinelazia intermedia, Subulura lacertilia and Parapharyngodon sp.) were recorded from the six different populations of A. nativo. There was considerable variation in overall prevalence of infection (1–42%) among study sites, but geographical distance among areas did not influence similarity in the composition of nematode assemblages. Overall intensity of infection was not affected by lizard body size and did not seem to affect host body condition, based on pooled data of all populations. The studied populations of the unisexual A. nativo had relatively low prevalences and intensities of infection compared to some bisexual congeners and to sympatric lizards from other families for which such data are available. We believe that the low richness of the nematode fauna associated with A. nativo, both locally and regionally, may reflect its narrow geographic distribution and the low diversity of habitats it occupies.

The reproductive biology of boreal forest herbs. II. Phenology of flowering and fruiting

1987 ◽  
Vol 65 (10) ◽  
pp. 2047-2056 ◽  
Author(s):  
Kaius Helenurm ◽  
Spencer C. H. Barrett
Keyword(s):  
Boreal Forest ◽  
Fruit Set ◽  
Pollen Limitation ◽  
Fruit Production ◽  
Fruit Removal ◽  
Cornus Canadensis ◽  
Forest Herbs ◽  
Pollinator Service ◽  
Maianthemum Canadense ◽  
Major Factors

The flowering and fruiting phenologies of 12 boreal forest herbs were recorded during 1979 (flowering and fruiting) and 1980 (flowering only) in spruce–fir forests of central New Brunswick. The species studied were Aralia nudicaulis, Chimaphila umbellata, Clintonia borealis, Cornus canadensis, Cypripedium acaule, Linnaea borealis, Maianthemum canadense, Medeola virginiana, Oxalis montana, Pyrola secunda, Trientalis borealis, and Trillium undulatum. Flowering in the community occurred from mid-May to the end of July. The order of flowering was maintained in the 2 years, but the degree of synchronization of inflorescences differed in several species. Fruiting in the community began in mid-July and extended beyond the end of September. The percentage of buds that ultimately bore fruit ranged from 0 (Cypripedium acaule) to 61% (Aralia nudicaulis). With the exception of Cypripedium acaule, which received little pollinator service, the self-incompatible species, Cornus canadensis, Maianthemum canadense, and Medeola virginiana, experienced the lowest levels of fruit-set. Pollen limitation and predation of developing fruit appear to be the major factors limiting percentage fruit-set in boreal forest herbs. Fruit production varied with time of flowering of inflorescences in several species, with periods of low fruit-set tending to coincide with lower densities of flowering inflorescences. Significant rates of fruit removal by herbivores occurred in all sarocochorous species. Disappearance of fruits from infructescences ranged from 31 (Medeola virginiana) to 95% (Aralia nudicaulis), with highest removal rates occurring during periods of greatest fruit availability.

Escalated aggression in interpopulation brook trout dyads: evidence for behavioural divergence

2003 ◽  
Vol 81 (5) ◽  
pp. 911-915 ◽  
Author(s):  
Robert Dunbrack ◽  
Lynn Clarke
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Low Cost ◽  
Isolated Populations ◽  
Communication Failure ◽  
Behavioural Assessment ◽  
Different Populations ◽  
The Cost ◽  
Population Norm

The "communication-failure" hypothesis states that individuals whose agonistic displays deviate from the population norm are selected against because of the greater likelihood of their becoming involved in escalated contests. A corollary of this hypothesis is that the level of aggression in dyadic (pairwise) contests over resources is predicted to be higher the greater the behavioural divergence between the two contestants. Display divergence between two contestants from different populations should exceed that in intrapopulation dyads, consequently this prediction can be tested by comparing levels of aggression in contests between interpopulation dyads with those in contests between intra population dyads. We carried out such a test using brook trout (Salvelinus fontinalis) from two isolated populations in eastern Newfoundland. In initial encounters, the nipping rate (a measure of aggressiveness) of individuals from one of these populations was significantly higher in interpopulation dyads than in intrapopulation dyads. These results are consistent with the communication-failure hypothesis, as well as with the view that behavioural assessment, using low-cost stereotypic displays, reduces the cost of interactions over resources for both contestants.

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