Population Studies in Predominantly Self-Pollinated Species. IV. Seasonal Fluctuations in Estimated Values of Genetic Parameters in Lima Bean Populations

Population studies for determining seasonal fluctuations of N. vinitor indicated that the appearance or disappearance of populations within a short time can be attributed mainly to its highly migratory behavior. N. vinitor always migrated when host plants dried up, and sometimes also when they were still green. Continuous quantitative records of flight activity, made near the population source, showed that the seasonal migrations of N. vintor closely reflected its population curve. As populations increased and declined throughout the season, migrants were produced continuously, resulting in a fairly smooth succession of departing individuals which became particularly obvious when large numbers suddenly discharged which occurred when special weather conditions caused sudden excessive flights.

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Population Studies on the Southern Black-Backed Gull

10.26686/wgtn.16946689 ◽

2021 ◽

Author(s):

◽

Robin Alexander Fordham

Keyword(s):

Breeding Success ◽

Food Supply ◽

Population Studies ◽

Ecological Studies ◽

Seasonal Fluctuations ◽

Age Composition ◽

Feeding Sites ◽

Larus Dominicanus ◽

The Social ◽

Present Distribution

<p>An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak non-breeding season population in 1964 exceeded 12,000 birds. Its growth has been closely associated with the increase of the human population, and the present distribution and dispersal of gulls is strongly influenced by the distribution of " artificial" feeding sites such as refuse tips and meatworks. The population is composed of breeding colonies, night roosting flocks and daily communal flocks which are inter-related by the social activities and dispersal of the birds. Thus the population is more or less integrated, rather than simply comprising discrete geographic units. Seasonal fluctuations in size and age composition of communal flocks are discussed. Breeding success varies between colonies. It is affected by mammalian predation in some, and by drowning in others, while the largest colonies are comparatively safe for breeding birds. The rapid growth of the whole population in the last five to 10 years appears to have some influence on nesting density, clutch size, spread of laying and overall breeding success. In recent years production of young has been twice that required to maintain the population which has grown at the rate of not less than 7.2% annually. Mortality of banded gulls inside and outside the colony is described and the influence of several factors on chick mortality examined. The principal factor limiting the population appears to be the food supply in relation to the number of birds. When numbers increase and the food supply diminishes, major regulation of the population is apparently achieved in the colony by predation (but not cannibalism) of young by adults. Dispersal of banded gulls from the Wellington colonies is very restricted.</p>

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Population Studies on the Southern Black-Backed Gull

10.26686/wgtn.16946689.v1 ◽

2021 ◽

Author(s):

◽

Robin Alexander Fordham

Keyword(s):

Breeding Success ◽

Food Supply ◽

Population Studies ◽

Ecological Studies ◽

Seasonal Fluctuations ◽

Age Composition ◽

Feeding Sites ◽

Larus Dominicanus ◽

The Social ◽

Present Distribution

<p>An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak non-breeding season population in 1964 exceeded 12,000 birds. Its growth has been closely associated with the increase of the human population, and the present distribution and dispersal of gulls is strongly influenced by the distribution of " artificial" feeding sites such as refuse tips and meatworks. The population is composed of breeding colonies, night roosting flocks and daily communal flocks which are inter-related by the social activities and dispersal of the birds. Thus the population is more or less integrated, rather than simply comprising discrete geographic units. Seasonal fluctuations in size and age composition of communal flocks are discussed. Breeding success varies between colonies. It is affected by mammalian predation in some, and by drowning in others, while the largest colonies are comparatively safe for breeding birds. The rapid growth of the whole population in the last five to 10 years appears to have some influence on nesting density, clutch size, spread of laying and overall breeding success. In recent years production of young has been twice that required to maintain the population which has grown at the rate of not less than 7.2% annually. Mortality of banded gulls inside and outside the colony is described and the influence of several factors on chick mortality examined. The principal factor limiting the population appears to be the food supply in relation to the number of birds. When numbers increase and the food supply diminishes, major regulation of the population is apparently achieved in the colony by predation (but not cannibalism) of young by adults. Dispersal of banded gulls from the Wellington colonies is very restricted.</p>

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Characterization of AFLP markers in damselflies: prevalence of codominant markers and implications for population genetic applications

Genome ◽

10.1139/g01-051 ◽

2001 ◽

Vol 44 (4) ◽

pp. 677-684 ◽

Cited By ~ 27

Author(s):

A Wong ◽

M R Forbes ◽

M L Smith

Keyword(s):

Population Genetic ◽

Genetic Parameters ◽

Fragment Length Polymorphism ◽

Population Studies ◽

Natural Populations ◽

Aflp Analysis ◽

Polymorphic Markers ◽

Dominant Markers ◽

Nehalennia Irene

Amplified fragment length polymorphism (AFLP) analysis is becoming increasingly popular as a method for generating molecular markers for population genetic applications. For practical considerations, it is generally assumed in population studies that AFLPs segregate as dominant markers, i.e., that present and absent are the only possible states of a given locus. We tested the assumption of dominance in natural populations of the damselfly Nehalennia irene (Hagen) (Odonata: Coenagrionidae). Electro-blotted AFLP products from 21 samples were probed with individual markers. Eleven markers were analyzed, of which two were monomorphic and nine were polymorphic. Only two of the polymorphic markers behaved in a strictly dominant manner. The remaining seven polymorphic markers displayed various degrees of codominance, with 210 visible alleles in the sample. Of the three markers displaying the highest degree of variability, two contained microsatellite repeat tracts. Our results suggest that the assumption of dominance is unfounded. As a result, AFLP analysis may be unsuitable for estimating several important population genetic parameters, including genetic diversity.Key words: AFLP, population genetics, dominant markers, microsatellite, insect, damselfly.

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