The preference for melanistic males was studied in two populations of eastern mosquitofish (Gambusia holbrooki, Pisces: Poeciliidae), one from Florida and one from northern Italy. Melanism in the eastern mosquitofish is a Y--linked character, expressed in males only. Melanistic males have black spots varying in size and number. In the Florida population, melanistic males are common, whereas in ...

We estimated the mass budget for mercury (Hg) seasonally deposited into the Florida Everglades and investigated seasonality of Hg cycling by analyzing data obtained for water, soil, flocculent detrital material (floc), periphyton, and mosquitofish collected throughout the Everglades freshwater marshes in the 2005 dry and wet seasons. Higher wet season total Hg (THg) in soil, floc, and periphyto...

Wildlife managers are concerned that insecticides used to control mosquitoes could suppress invertebrates on which wildlife feed. We assessed whether ultra-low volume (ULV) applications of pyrethrin, permethrin, and malathion for control of adult mosquitoes reduced macroinvertebrate abundance and biomass or killed mosquitofish in seasonal wetlands in California. Pyrethrin was applied over 3 sea...

Socially influenced mate choice behavior is currently a growing field in the study of sexual selection and evolution. Here, we provide the first description of male Grijalva mosquitofish (Heterophallus milleri) courtship behavior, and further report on an unparalleled “audience effect” in that species. Lab-reared male Grijalva mosquitofish significantly increased their preference for an initial...

BACKGROUND Recent studies have demonstrated that fish display rudimentary numerical abilities similar to those observed in mammals and birds. The mechanisms underlying the discrimination of small quantities (<4) were recently investigated while, to date, no study has examined the discrimination of large numerosities in fish. METHODOLOGY/PRINCIPAL FINDINGS Subjects were trained to discriminate...

The mosquitofish, Gambusia affinis, and the inland silverside, Menidia beryllina, were evaluated in experimental, one-tenth hectare wild rice plots in Lake County, California, for their impact on densities of Culex tarsalis, Anopheles freeborni and Anopheles franciscanus. Gambusia affinis were tested at 0.6 and 1.7 kg/ha and the silversides at ca. 0.9 kg/ha. The silversides did not survive well...

Spontaneous rotational preferences in swimming of mosquitofish (Gambusia holbrooki) were investigated. Females, but not males, swam in circular tanks preferentially anticlockwise in the afternoon but not in the morning. Females' rotational preferences appeared to be related to a sun-compass orientation mechanism, as they disappeared under diffuse lighting conditions and when using naive females...

"Dye-coupling", whole-mount immunohistochemistry for gap junction channel protein connexin 35 (Cx35), and freeze-fracture replica immunogold labeling (FRIL) reveal an abundance of electrical synapses/gap junctions at glutamatergic mixed synapses in the 14th spinal segment that innervates the adult male gonopodium of Western Mosquitofish, Gambusia affinis (Mosquitofish). To study gap junctions' ...

Interspecific competition may be particularly exacerbated when occurring between native and invasive alien species, with environmental conditions affecting drivers of natural selection shaping spatio-temporal dynamics animal communities. The effects invaders are evident in aquatic ecosystems delicate complex balances, such as Mediterranean coastal wetlands, characterized by unpredictable water ...