Abstracts » Zoology and wildlife conservation

Sexual dichromatism in convict cichlids: the ethological significance of female ventral coloration

Article Abstract:

Live and dummy stimulus fishes were used to determine why female convict cichlids, Cichlasoma nigrofasciatum, develop orange ventral coloration. Results show that male cichlids are insensitive to ventral color variation, while females seem to use color pattern as a visual cue. Females tend to be aggressive towards brightly colored fishes, while bright females exhibit the least aggression towards an intruding female of intermediate coloration. The findings indicate that sexual dichromatism in C. nigrofasciatum influences intrasexual aggression among females.

Sexual behavior in animals, Animal sexual behavior, Aggressive behavior in animals, Animal aggression, Animal behavior, Color of animals, Animal coloration

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Fine-scale spatial structuring in cackling Canada geese related to reproductive performance and breeding philopatry

Article Abstract:

The potential mechanisms that may be responsible for promotion and maintenance of genetic structuring specifically the relationships between breeding philopatry, the proximity of relatives and nesting success are investigated. The result suggests that patterns of fine-scale genetic differentiation are associated with reproductive success and increases in success coupled with breeding philopatry may further promote fine-scale genetic structuring.

Sexual behavior, Physiological aspects, Genetic aspects, Birds, Bird breeding, Canada goose

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Effects of competitor-to-resource ratio on aggression and size variation within groups of convict cichlids

Article Abstract:

The resource theory predictions are tested, which state that the intensity of competitive aggression, degree of resource monopolization, and variation in fitness would be highest at intermediate levels of the spatial clumping of resources. The study suggests that competitor-to-resource ratio is a useful measure of the degree of spatial clumping of resources.

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