The omnipresence of microplastics and nanoparticles has led to their entry into the fresh marine aquatic systems affected biota. present study aims evaluate impact interaction polyethylene microplastic (PE-MPs) zinc oxide (ZnO-NPs) in mosquito fish, Gambusia holbrooki. For this, fish were exposed 100 µg L−1 PE-MPs (group 2), 200 3), 50 ZnO-NPs 4), combined with 5), 6) control 1) for 14 days. as...

We studied detour responses of male mosquitofish faced with a vertical-bar barrier through which a group of females was visible. Mosquitofish showed a consistent population bias to detour the barrier preferentially leftwise when a straight barrier was used, whilst the asymmetry disappeared if a U-shaped barrier was used. The leftward bias was apparent even when using a simulated-predator as a t...

Contamination of freshwater ecosystems with nitrate is a growing global concern. Although nitrate pollution is recognized as a cause of aquatic eutrophication, few studies have examined the possible physiological impacts of nitrate exposure. In this study, we surveyed several reproductive variables of viviparous female Gambusia holbrooki (Poeciliidae) captured from eight springs in Florida. The...

Genetic analyses contribute to studies of biological invasions by mapping the origin and dispersal patterns of invasive species occupying new territories. Using microsatellite loci, we assessed the genetic diversity and spatial population structure of mosquitofish (Gambusia holbrooki) that had invaded Spanish watersheds, along with the American locations close to the suspected potential source ...

Females of many species mate with multiple males during the course of a single round of reproduction (Davies, 1991; Birkhead & Mùller, 1992). However, secure estimates of the frequency of concurrent multiple paternity in most cases awaited the application of molecular markers (Avise, 1994) that permit documentation of when copulations result in fertilizations such that individual broods are mul...

Previous laboratory studies have demonstrated that estrogenic and antiandrogenic chemicals can alter several sexual characteristics in male poeciliid fishes. Whether similar disturbances occur under field conditions remains to be confirmed. Lake Apopka, Florida, is contaminated with numerous chemicals, some of which possess endocrine-disrupting activity. Male mosquitofish (Gambusia holbrooki) w...

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 ...

The present study investigated whether fluctuating asymmetry can serve as a useful biomarker of environmental stress in the eastern mosquitofish (Gambusia holbrooki). Fluctuating asymmetry was measured in sexually mature females sampled from two Florida, USA, coastal streams: The Fenholloway River, which is dominated by effluent from a paper mill, and Spring Creek, a tributary to the Fenhollowa...

In most livebearing fish, the gravid spot is an excellent marker to identify brooding females, however its use to predict progress of embryonic development, brood size, timing of parturition and overall reproductive potential of populations remain unexplored. Therefore, to understand these relationships, this study quantified visual attributes (intensity and size) of the gravid spot in relation...

In social animal groups, an individual's spatial position is a major determinant of both predation risk and foraging rewards. Additionally, the occupation of positions in the front of moving groups is generally assumed to correlate with the initiation of group movements. However, whether some individuals are predisposed to consistently occupy certain positions and, in some instances, to consist...