نتایج جستجو برای: mosquitofish

تعداد نتایج: 326  

Journal: :Biology letters 2011
Rosemary Knapp Edie Marsh-Matthews Luanne Vo Sarah Rosencrans

Sex steroids play major roles in vertebrate sexual differentiation. Unexpectedly, we now find that exposure to elevated levels of the naturally occurring stress hormone cortisol can also masculinize sexually dimorphic morphological characters and behaviour in adult female mosquitofish (Gambusia affinis) in a dose-dependent manner. Females masculinized by cortisol developed elongated anal fins w...

2015
Loeske E B Kruuk Julianne Livingston Andrew Kahn Michael D Jennions

Mothers vary in their effects on their offspring, but studies of variation in maternal effects rarely ask whether differences between mothers are consistent for sons and daughters. Here, we analysed maternal effects in the mosquitofish Gambusia holbrooki for development time and adult size of sons and daughters, and a primary male sexual character (gonopodium length). We found substantial mater...

Journal: :Journal of the American Mosquito Control Association 1990
A L Linden J J Cech

Mosquitofish are widely used for biological control of mosquito larvae in rice fields, but the presence of different types of vegetation or alternative arthropod prey affects the performance of the fish. Feeding experiments were conducted in 4 rice field vegetation zones. Overall, predation was maximal in young and mature rice, moderate in the submerged naiad vegetation, and minimal in areas of...

2016
Isobel Booksmythe Megan L. Head J. Scott Keogh Michael D. Jennions

Male genitalia often show remarkable differences among related species in size, shape and complexity. Across poeciliid fishes, the elongated fin (gonopodium) that males use to inseminate females ranges from 18 to 53% of body length. Relative genital size therefore varies greatly among species. In contrast, there is often tight within-species allometric scaling, which suggests strong selection a...

Journal: :Biology letters 2011
Therese Chen Madeleine Beekman Ashley J W Ward

While studies of sexual selection focus primarily on female choice and male-male competition, males should also exert mate choice in order to maximize their reproductive success. We examined male mate choice in mosquitofish, Gambusia holbrooki, with respect to female size and female dominance. We found that the number of mating attempts made by a male was predicted by the dominance rank of fema...

Journal: :Evolution; international journal of organic evolution 2007
R Brian Langerhans Matthew E Gifford Everton O Joseph

Although theory indicates that natural selection can facilitate speciation as a by-product, demonstrating ongoing speciation via this by-product mechanism in nature has proven difficult. We examined morphological, molecular, and behavioral data to investigate ecology's role in incipient speciation for a post-Pleistocene radiation of Bahamas mosquitofish (Gambusia hubbsi) inhabiting blue holes. ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1994
K T Scribner J C Avise

Two species of mosquitofish (family Poeciliidae) known to hybridize in nature were introduced into freshwater habitats inside Biosphere 2, and their population genetics were monitored after 2 years. Within four to six generations, nuclear and cytoplasmic markers characteristic of Gambusia holbrooki had risen greatly in frequency, although some Gambusia affinis alleles and haplotypes were retain...

Journal: :Journal of the American Mosquito Control Association 1988
V L Kramer R Garcia A E Colwell

The mosquito control potential of the mosquitofish and Bacillus thuringiensis var. israelensis (Bti) were evaluated in experimental wild rice fields in Lake County, California. Fields were assigned one of six treatment: control, 1.1 kg/ha G. affinis, 3.4 kg/ha G. affinis, Bti only (6 kg/ha Vectobac granules), 1.1 kg/ha G. affinis plus Bti and 3.4 kg/ha G. affinis plus Bti. Gambusia affinis, at ...

2015
Sujan M. Henkanaththegedara Justin D. L. Fisher Daniel C. McEwen Craig A. Stockwell

Desert springs, which harbor diverse and endemic invertebrate assemblages, are often used as refuge habitats for protected fish species. Additionally, many of these springs have been colonized by invasive fish species. However, the potential impacts of recently established fish populations on invertebrate communities in desert springs have been relatively unexplored. We conducted a mesocosm exp...

Journal: :Ecotoxicology and environmental safety 2006
June-Woo Park Jacques Rinchard Fujun Liu Todd A Anderson Ronald J Kendall Christopher W Theodorakis

The perchlorate anion--an oxidizer found in rockets, missiles, some ammunition, flares, airbags, and fireworks--occurs as a contaminant in ground and surface water in many parts of the United States. Its toxic effects include inhibition of thyroid hormone synthesis. To investigate its chronic toxicity, mosquitofish (Gambusia holbrooki) adults and fry were exposed to aqueous sodium perchlorate a...

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