Influence of exploitation on population structure, spatial distribution and reproductive success of dioecious species in a fragmented cloud forest in India

2000 ◽  
Vol 94 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Hema Somanathan ◽  
Renee M. Borges
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
Reproductive Success ◽  
Cloud Forest ◽  
Dioecious Species

scholarly journals Host density predicts the probability of parasitism by avian brood parasites

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180204 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore
Keyword(s):  
Spatial Distribution ◽  
Reproductive Success ◽  
Host Species ◽  
Field Data ◽  
Host Density ◽  
Brood Parasites ◽  
Parasitism Rates ◽  
Analyse Data ◽  
First Time ◽  
Determining Factor

The spatial distribution of hosts can be a determining factor in the reproductive success of parasites. Highly aggregated hosts may offer more opportunities for reproduction but can have better defences than isolated hosts. Here we connect macro- and micro-evolutionary processes to understand the link between host density and parasitism, using avian brood parasites as a model system. We analyse data across more than 200 host species using phylogenetic comparative analyses and quantify parasitism rate and host reproductive success in relation to spatial distribution using field data collected on one host species over 6 years. Our comparative analysis reveals that hosts occurring at intermediate densities are more likely to be parasitized than colonial or widely dispersed hosts. Correspondingly, our intraspecific field data show that individuals living at moderate densities experience higher parasitism rates than individuals at either low or high densities. Moreover, we show for the first time that the effect of host density on host reproductive success varies according to the intensity of parasitism; hosts have greater reproductive success when living at high densities if parasitism rates are high, but fare better at low densities when parasitism rates are low. We provide the first evidence of the trade-off between host density and parasitism at both macro- and micro-evolutionary scales in brood parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

scholarly journals Reproductive biology of Macleania rupestris (Ericaceae), a pollen-limited Neotropical cloud-forest species in Costa Rica

2010 ◽  
Vol 26 (3) ◽  
pp. 351-354 ◽  
Author(s):  
Eric J. Fuchs ◽  
Jeffrey Ross-Ibarra ◽  
Gilbert Barrantes
Keyword(s):  
Costa Rica ◽  
Relative Humidity ◽  
Reproductive Success ◽  
Cloud Forest ◽  
Fruit Production ◽  
Foraging Activity ◽  
High Altitudes ◽  
Forest Species ◽  
Effective Time ◽  
Complex Interactions

The reproductive success of hummingbird-pollinated plants often depends on complex interactions between environmental conditions and pollinator biology (Navarro 1999, Stiles 1985, Wolf et al. 1976). The effect of environment on reproductive success of hummingbird-pollinated plants is particularly pronounced at high altitudes, where large daily fluctuations in temperature, relative humidity and solar radiation limit the effective time for photosynthesis (Cavieres et al. 2000) and affect foraging activity (Navarro 1999) and abundance of pollinators (Rahbek 1997). At high altitudes in the tropical cloud forests of Costa Rica these factors may have serious impacts on fruit production.

scholarly journals Parasitic infection reduces dispersal of ciliate host

2010 ◽  
Vol 7 (3) ◽  
pp. 327-329 ◽  
Author(s):  
Simon Fellous ◽  
Elsa Quillery ◽  
Alison B. Duncan ◽  
Oliver Kaltz
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
Short Distance ◽  
Parasitic Infection ◽  
Genetic Population Structure ◽  
Paramecium Caudatum ◽  
Dispersal Capacity ◽  
Genetic Population ◽  
Social Aggregation ◽  
Aggregation Behaviour

Parasitic infection can modify host mobility and consequently their dispersal capacity. We experimentally investigated this idea using the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata . We compared the short-distance dispersal of infected and uninfected populations in interconnected microcosms. Infection reduced the proportion of hosts dispersing, with levels differing among host clones. Host populations with higher densities showed lower dispersal, possibly owing to social aggregation behaviour. Parasite isolates that depleted host populations most had the lowest impact on host dispersal. Parasite-induced modification of dispersal may have consequences for the spatial distribution of disease, host and parasite genetic population structure, and coevolution.

scholarly journals Do metrics of sexual selection conform to Bateman's principles in a wind-pollinated plant?

2019 ◽  
Vol 286 (1905) ◽  
pp. 20190532 ◽  
Author(s):  
Jeanne Tonnabel ◽  
Patrice David ◽  
John R. Pannell
Keyword(s):  
Spatial Distribution ◽  
Sexual Selection ◽  
Reproductive Success ◽  
Pollen Dispersal ◽  
Male Fitness ◽  
Female Fitness ◽  
Dioecious Plant ◽  
Common Gardens ◽  
Mate Acquisition ◽  
Mercurialis Annua

Bateman's principles posit that male fitness varies more, and relies more on mate acquisition, than female fitness. While Bateman's principles should apply to any organism producing gametes of variable sizes, their application to plants is potentially complicated by the high levels of polyandry suspected for plants, and by variation in the spatial distribution of prospective mates. Here we quantify the intensity of sexual selection by classical Bateman metrics using two common gardens of the wind-pollinated dioecious plant Mercurialis annua . Consistent with Bateman's principles, males displayed significantly positive Bateman gradients (a regression of fitness on mate number), whereas the reproductive success of females was independent of their ability to access mates. A large part of male fitness was explained by their mate number, which in turn was associated with males' abilities to disperse pollen. Our results suggest that sexual selection can act in plant species in much the same way as in many animals, increasing the number of mates through traits that promote pollen dispersal.

Rapport des sexes, effort et succès de reproduction chez Rubus chamaemorus, plante herbacée vivace dioïque de distribution subarctique

1987 ◽  
Vol 65 (12) ◽  
pp. 2628-2639 ◽  
Author(s):  
Pascale Dumas ◽  
Lucie Maillette
Keyword(s):  
Reproductive Success ◽  
Sexual Reproduction ◽  
Sex Ratios ◽  
Female Flower ◽  
Fruit Production ◽  
Climatic Conditions ◽  
Total Biomass ◽  
Dioecious Species ◽  
Pollinator Behaviour ◽  
Rubus Chamaemorus

Studies published on the reproductive success of dioecious species concentrate on the role of sex ratios and pollinator behaviour. In the case of Rubus chamaemorus L., a circumboreal dioecious species, we hypothesized that flower survival and biomass allocation to reproductive tissues, which are climate dependent, also influence fruit production. Only 0.05% of total biomass is allocated to reproduction, whereas 94% goes to underground organs responsible for vegetative propagation. Many male (28 – 51%) and female flower buds (35 – 54%) and young fruits (24–51%) die prematurely mainly because of the climate; fruit production then becomes independent from initial female flower density. The scarcity of female flowers at most sites (except near open water) limits fruit production. The limited sexual reproduction would allow cloudberry to maintain somatic resources, thereby increasing the longevity of individuals and their chance of encountering the climatic conditions required for reproductive success. Such a strategy is adaptive in a variable climate like that of the subarctic. Furthermore, the reduced importance of sexual reproduction would diminish the need to optimize sex ratios. Other selective pressures (e.g., competition) would then favour male clones in most sites, in spite of the unproductive pollen excess.

Ecology of the invading moss species Orthodontium lineare in Sweden: Spatial distribution and population structure

Ecography ◽  
1989 ◽  
Vol 12 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Lars Hedenas ◽  
Tomas Herben ◽  
Hakan Rydin ◽  
Lars Soderstrom
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
Moss Species

scholarly journals Population structure and spatial distribution of porbeagles (Lamna nasus) in Irish waters

2019 ◽  
Vol 76 (6) ◽  
pp. 1581-1590 ◽  
Author(s):  
Luke W J Cameron ◽  
William K Roche ◽  
Jonathan D R Houghton ◽  
Paul J Mensink
Keyword(s):  
Population Structure ◽  
Spatial Distribution ◽  
North Atlantic ◽  
Population Decline ◽  
The North ◽  
Aggregation Site ◽  
Show Evidence ◽  
Long Term Trends ◽  
Almost All

Abstract Porbeagles throughout the North Atlantic have experienced severe population decline through overfishing, with the northeastern population listed as critically endangered. Management of this population is constrained by the paucity of data on porbeagle population structure, distribution and behaviour in this region. Here we use a long-term (47 year) Irish capture-mark-recapture dataset to investigate the population structure, spatial distribution and seasonal movements of this species. From 1970–2017, a total of 268 sharks (9 recaptures) were ID tagged, with most individuals likely being juvenile based on length at maturity estimates (mean total length = 143.9 cm, SD = 35.4). Almost all captures were recorded at three distinct locations near angling hubs along the south, west and north coasts with catches peaking in August. Long-term trends in capture date indicated a shift towards earlier capture dates in the northern site (n = 153). Our findings suggest Irish waters may act as a persistent summer aggregation site for juveniles, which show evidence for seasonal site fidelity, returning to nearby locations between years. These findings demonstrate the utility of such programmes, which can be implemented, with minimal expense by engaging with the angling sector, to elucidate the population structure and distribution of wide-ranging fish species.

Sign in / Sign up

Export Citation Format

Share Document