Trophic strategies of the invasive Twospot livebearer (Pseudoxiphophorus bimaculatus, Teleostei: Poeciliidae) in a gradient of environmental quality in central Mexico

Abstract

<jats:p>ABSTRACT Pseudoxiphophorus bimaculatus is an invasive species widely spread throughout freshwater ecosystems in central Mexico, for that reason we described its trophic strategy into a gradient of environmental quality. We sampled individuals of P. bimaculatus at eight sites located in the Lerma-Chapala and Pánuco River Basins during dry season. These basins have been impacted by industrialization and urbanization processes, but are considered as water reserves in México. To evaluate the environmental quality of the river, we applied the Visual-based Habitat Assessment, the Index of Biological Integrity and the Family-level Biotic Index. We assessed the trophic guild, the diet width, the omnivory level, and the diet selectivity. We also explored the relation of trophic strategies with the habitat condition. We captured a total of 202 individuals of P. bimaculatus from 10 to 67 mm of SL, finding a total of 24 food items. The diet of P. bimaculatus was composed of terrestrial, aquatic insects and bony fish. Pseudoxiphophorus bimaculatus in some sites can feed on different trophic levels, in other it is a specialist and secondary consumer. We found that P. bimaculatus changes its diet according the alterations in the habitat structure, water quality, and biotic integrity. Moreover, this invasive species can endure changes in the trophic web and food availability.</jats:p>

Trophic biology of the twospot livebearer, Pseudoxiphophorus bimaculatus, an invasive fish in Teuchitlán River, central Mexico

“…This could indicate that P. bimaculatus may function as a vehicle of allochthonous energy into the Teuchitlán River system. Terrestrial insects are abundant items in freshwater stream habitats with different levels of human perturbation and, as explained above, riparian vegetation seems to be key in the transfer of terrestrial insects to water, making them available for fish ingestion (Carbajal-Becerra et al, 2020;Nakano et al, 1999;Wipfli & Baxter, 2010). In other water bodies, human perturbation can affect the terrestrialaquatic energy flux, increasing the allochthonous input by terrestrial insects (Vital-Rodríguez et al, 2017).…”

“…It is clear that P. bimaculatus should be considered a species with high invasive potential and a serious risk for the freshwater ecosystems of central Mexico, a region that has been recognized as a very important hotspot for freshwater fish conservation (Carbajal-Becerra et al, 2020;Domínguez-Domínguez et al, 2006;Miller, 1986), with endemicity of up to 70% and a dramatic decrease in native fish populations (De la Vega-Salazar, 2006;Domínguez-Domínguez et al, 2008;Lyons et al, 1998). The introduction of this species into water bodies of the area is therefore to be avoided, and more attention must be paid to the stocking process of fish species of commercial value and the release of exotic fishes for mosquito control or ornamental purposes.…”

Examination of the Trexler-DeAngelis Model of Maternal Provisioning Reveals That Matrotrophy Is Costly

“…In these cases, neither stomach fullness nor BC would be reliable indicators of food availability. Therefore, the lack of associations between degree of matrotrophy and our proxies for food availability must be interpreted with caution, since future examination of additional measures of food availability, such as in situ abundances of algae and aquatic invertebrates (Quintans et al, 2009;Carbajal-Becerra et al, 2020), may provide supporting evidence for this prediction of the Trexler-DeAngelis model.…”

The invasive twospot livebearer's biology, and its current and potential global distribution

“…The twospot livebearer can change its diet according to alterations in habitat structure, water quality and biotic integrity (Mar‐Silva et al ., 2021). It is recognized as an omnivore and in some regions as a carnivorous‐insectivore (Carbajal‐Becerra et al ., 2020; Guzmán Santiago & Olvera Soto, 1996; Mar‐Silva et al ., 2021; Mata Salcedo, 2007; Ramírez Santillán, 2022; Trujillo‐Jiménez & Toledo Beto, 2007). There are no differences in the diets of both sexes in terms of seasonality and individual size, but it has been reported that females consume more plant‐based food than males (Trujillo‐Jiménez, 1998).…”