The Dynamics of a Natural Population of Paramecium and the Role of Interspecific Competition in Community Stucture

10.2307/3509 ◽  
1972 ◽  
Vol 41 (1) ◽  
pp. 137 ◽  
Author(s):  
Douglas E. Gill ◽  
Nelson G. Hairston
Keyword(s):  
Interspecific Competition ◽  
Natural Population ◽  
Community Stucture

Habitat Segregation in Ground Crickets: The Role of Interspecific Competition and Habitat Selection

Ecology ◽  
1984 ◽  
Vol 65 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Daniel J. Howard ◽  
Richard G. Harrison
Keyword(s):  
Habitat Selection ◽  
Interspecific Competition ◽  
Habitat Segregation

Role of sediment structuring by detritus on colonization and interspecific competition of one native and one invasive submerged macrophyte

Hydrobiologia ◽  
2019 ◽  
Vol 834 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Mário Sérgio Dainez-Filho ◽  
Thaísa Sala Michelan ◽  
Nayara Louback-Franco ◽  
Douglas Costa Souza ◽  
Emanuel Giovani Cafofo ◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Submerged Macrophyte

scholarly journals First empirical evidence of naturally occurring androgenesis in vertebrates

2017 ◽  
Vol 4 (5) ◽  
pp. 170200 ◽  
Author(s):  
Miguel Morgado-Santos ◽  
Sara Carona ◽  
Luís Vicente ◽  
Maria João Collares-Pereira
Keyword(s):  
Empirical Evidence ◽  
Random Sample ◽  
Natural Population ◽  
Natural Occurrence ◽  
Human Interference ◽  
Mitochondrial Markers ◽  
Viable Offspring ◽  
Naturally Occurring ◽  
Mitochondrial Fragment

Androgenesis among vertebrates is considered a rare phenomenon, with some cases reported so far, but linked to experiments involving gamete manipulation (artificial androgenesis). Herein, we report the first empirical evidence of the natural occurrence of spontaneous androgenesis in a vertebrate, the Squalius alburnoides allopolyploid complex. A genetically screened random sample of a natural population was allowed to reproduce in an isolated pond without any human interference, and the viable offspring obtained was later analysed for paternity. Both nuclear and mitochondrial markers showed that the only allodiploid fish found among all the allotriploid offspring was androgenetically produced by an allodiploid male. This specimen had no female nuclear genomic input, and the sequence of the mitochondrial fragment examined differed from that of the male progenitor, matching one of the parental females available in the pond, probably the mother. The possible role of androgenesis in the reproductive dynamics of this highly successful vertebrate complex is discussed.

scholarly journals Travelling waves for diffusive and strongly competitive systems: Relative motility and invasion speed

2015 ◽  
Vol 26 (4) ◽  
pp. 521-534 ◽  
Author(s):  
LÉO GIRARDIN ◽  
GRÉGOIRE NADIN
Keyword(s):  
Interspecific Competition ◽  
Travelling Waves ◽  
A Priori ◽  
Travelling Wave ◽  
Volterra System ◽  
Multiplicative Constant ◽  
Competitive Systems ◽  
Invading Species ◽  
Homogeneous Domains

Our interest here is to find the invader in a two species, diffusive and competitive Lotka–Volterra system in the particular case of travelling wave solutions. We investigate the role of diffusion in homogeneous domains. We might expect a priori two different cases: strong interspecific competition and weak interspecific competition. In this paper, we study the first one and obtain a clear conclusion: the invading species is, up to a fixed multiplicative constant, the more diffusive one.

Interspecific Competition and Population Control in Freshwater Fish

1956 ◽  
Vol 13 (3) ◽  
pp. 327-342 ◽  
Author(s):  
P. A. Larkin
Keyword(s):  
Interspecific Competition ◽  
Freshwater Fish ◽  
Quantitative Data ◽  
Population Control ◽  
Feeding Habits ◽  
Reproductive Potential ◽  
Habitat Type ◽  
Fish Populations ◽  
Population Interaction

Interspecific competition is defined as the demand of more than one organism for the same resource of the environment in excess of immediate supply. When two species are "competing for a niche" the term competition has been used to include phenomena such as predation of the two species on each other, competition to avoid a parasite, etc. Making this distinction in natural situations is unrealistic. In the limited sense in which interspecific competition is defined above, it is a discrete phenomenon, which with other phenomena such as predation, can be measured as a factor involved in interaction between species.Freshwater environments offer comparatively few opportunities for specialization in fishes. In consequence many species have a relatively wide tolerance of habitat type, a flexibility of feeding habits and in general share many resources of their environment with several other species of fish. Cannibalism and mutual predation are common complications of competitive relationships between species. The organization of freshwater fish communities is thus characterized by breadth at each level of the food chain rather than by a height of a pyramid of numbers. Flexible growth rate and high reproductive potential permit fish populations to tide over unfavorable periods of competition. In these circumstances it is difficult to separate the role of interspecific competition from other phenomena as a factor of population control. As a subordinate factor, predisposing fish to loss from other causes, interspecific competition may act to influence population levels. There is need for quantitative data and mathematical models for study of the types of population interaction typical in freshwater fish associations.

scholarly journals Role of behaviour in biological invasions and species distributions; lessons from interactions between the invasive Gammarus pulex and the native G. duebeni (Crustacea: Amphipoda)

2008 ◽  
Vol 77 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Jaimie T.A. Dick
Keyword(s):  
Interspecific Competition ◽  
Intraguild Predation ◽  
Native Species ◽  
Research Progress ◽  
Parasite Transmission ◽  
Species Introductions ◽  
Field Patterns ◽  
Alternative Hypotheses

In attempting to understand the distributions of both introduced species and the native species on which they impact, there is a growing trend to integrate studies of behaviour with more traditional life history/ecological approaches. The question of what mechanisms drive the displacement of the freshwater amphipod Gammarus duebeni by the often introduced G. pulex is presented as a case study. Patterns of displacement are well documented throughout Europe, but the speed and direction of displacement between these species can be varied. From early studies proposing interspecific competition as causal in these patterns, I review research progress to date. I show there has been no evidence for interspecific competition operating, other than the field patterns themselves, a somewhat tautological argument. Rather, the increased recognition of behavioural attributes with respect to the cannibalistic and predatory nature of these species gave rise to a series of studies unravelling the processes driving field patterns. Both species engage in ‘intraguild predation’ (IGP), with moulting females particularly vulnerable to predation by congeneric males. G. pulex is more able both to engage in and avoid this interaction with G. duebeni. However, several factors mediate the strength and asymmetry of this IGP, some biotic (e.g. parasitism) and others abiotic (e.g. water chemistry). Further, a number of alternative hypotheses that may account for the displacement (hybridization; parasite transmission) have been tested and rejected. While interspecific competition has been modelled mathematically and found to be a weak interaction relative to IGP, mechanisms of competition between these Gammarus species remain largely untested empirically. Since IGP may be finely balanced in some circumstances, I conclude that the challenge to detect interspecific competition remains and we require assessment of its role, if any, in the interaction between these species. Appreciation of behavioural attributes and their mediation should allow us to more fully understand, and perhaps predict, species introductions and resultant distributions.

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