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  1. Article ; Online: The Biology of Polymorphic Melanic Side-Spotting Patterns in Poeciliid Fishes

    Tanja C. Zerulla / Philip K. Stoddard

    Frontiers in Ecology and Evolution, Vol

    2021  Volume 8

    Abstract: Melanin-based color patterns are an emerging model for studying molecular and evolutionary mechanisms driving phenotypic correlations. Extensive literature exists on color patterns and their correlated traits in the family Poeciliidae, indicating that ... ...

    Abstract Melanin-based color patterns are an emerging model for studying molecular and evolutionary mechanisms driving phenotypic correlations. Extensive literature exists on color patterns and their correlated traits in the family Poeciliidae, indicating that these fishes are tractable models. We review the biology of polymorphic melanic side-spotting patterns characterized by macromelanophores forming irregular spotted patterns across fishes’ flanks. These patterns are present in the genera Gambusia, Limia, Phalloceros, Poecilia, and Xiphophorus. Their presence is controlled by dominant genes on autosomes or sex chromosomes. Variation in expression is under polygenic control; however, these genes’ identities are still largely unknown. In some Gambusia holbrooki and Poecilia latipinna, expression is dependent on low temperature exposure, but underlying molecular mechanisms are unknown. Spotted fish develop melanoma in rare cases and are a well-developed model for melanoma research. Little is known about other physiological correlates except that spotted G. holbrooki males exhibit higher basal cortisol levels than unspotted males and that metabolic rate does not differ between morphs in some Xiphophorus species. Behavioral differences between morphs are widespread, but specific to population, species, and social context. Spotted G. holbrooki males appear to be more social and more dominant. Juvenile spotted G. holbrooki have lower behavioral flexibility, and spotted X. variatus exhibit greater stress resistance. Findings conflict on whether morphs differ in sexual behavior and in sexual selection by females. Melanic side-spotting patterns are uncommon (<30%) in populations, although extreme high-frequency populations exist. This low frequency is surprising for dominant genes, indicating that a variety of selective pressures influence both these patterns and their correlated traits. Little is known about reproductive life history traits. Spotted G. holbrooki are larger and have higher survival when uncommon, but ...
    Keywords color polymorphism ; coloration ; melanism ; phenotypic integration ; pigmentation ; pleiotropy ; Evolution ; QH359-425 ; Ecology ; QH540-549.5
    Subject code 590
    Language English
    Publishing date 2021-01-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Nonlethal Effects of Pesticides on Web-Building Spiders Might Account for Rapid Mosquito Population Rebound after Spray Application

    Stefan N. Rhoades / Philip K. Stoddard

    Applied Sciences, Vol 11, Iss 4, p

    2021  Volume 1360

    Abstract: Spiders are important population regulators of insect pests that spread human disease and damage crops. Nonlethal pesticide exposure is known to affect behavior of arthropods. For spiders such effects include the inability to repair their webs or capture ...

    Abstract Spiders are important population regulators of insect pests that spread human disease and damage crops. Nonlethal pesticide exposure is known to affect behavior of arthropods. For spiders such effects include the inability to repair their webs or capture prey. In this study, nonlethal exposure of Mabel’s orchard spider ( Leucauge argyrobapta ) to the synthetic pyrethroid permethrin, via web application, interfered with web reconstruction and mosquito capture ability for 1–3 days. The timing of this loss-of-predator ecosystem function corresponds to the rapid population rebound of the yellow fever mosquito ( Aedes aegypti ) following insecticide application to control arbovirus epidemics. We suggest this temporal association is functional and propose that follow-up study be conducted to evaluate its significance.
    Keywords Aedes aegypti ; Leucauge argyrobapta ; nontarget effects ; permethrin ; pyrethroid ; Tetragnathidae ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Language English
    Publishing date 2021-02-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Predation and Crypsis in the Evolution of Electric Signaling in Weakly Electric Fishes

    Philip K. Stoddard / Alex Tran / Rüdiger Krahe

    Frontiers in Ecology and Evolution, Vol

    2019  Volume 7

    Abstract: Eavesdropping by electroreceptive predators poses a conflict for weakly electric fish, which depend on their Electric Organ Discharge (EOD) signals both for navigation and communication in the dark. The EODs that allow weakly electric fish to ... ...

    Abstract Eavesdropping by electroreceptive predators poses a conflict for weakly electric fish, which depend on their Electric Organ Discharge (EOD) signals both for navigation and communication in the dark. The EODs that allow weakly electric fish to electrolocate and communicate in the dark may attract electroreceptive predators such as catfishes and Electric Eels. These predators share with their prey the synapomorphy of passive electric sense supported by ampullary electroreceptors that are highly sensitive to low-frequency electric fields. Any low-frequency spectral components of the EOD make weakly electric fish conspicuous and vulnerable to attack from electroreceptive predators. Accordingly, most weakly electric fish shift spectral energy upwards or cloak low-frequency energy with compensatory masking signals. Subadults and females in particular emit virtually no low-frequency energy in their EODs, whereas courting males include a significant low-frequency component, which likely attracts females, but makes the signals conspicuous to predators. Males of species that coexist with the most predators tend to produce the least low-frequency signal energy, expressing sexual dimorphism in their signals in less risky ways. In these respects, electric signals follow the classic responses to opposing forces of natural and sexual selection, as exemplified in the visual signals of guppies and the acoustic signals of Túngara frogs. Unique to electric fish is that the electric signal modifications that help elude detection by electroreceptive predators are additions to the basal signal rather than losses of attractive components. These enhancements that enable crypsis are energetically costly, but have also provided the evolutionary substrates for subsequent sexual selection and species identity characters.
    Keywords catfish ; electroreception ; Gymnotiformes ; Mormyridae ; predation ; sensory drive ; Evolution ; QH359-425 ; Ecology ; QH540-549.5
    Subject code 590
    Language English
    Publishing date 2019-07-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Circadian and social cues regulate ion channel trafficking.

    Michael R Markham / M Lynne McAnelly / Philip K Stoddard / Harold H Zakon

    PLoS Biology, Vol 7, Iss 9, p e

    2009  Volume 1000203

    Abstract: Electric fish generate and sense electric fields for navigation and communication. These signals can be energetically costly to produce and can attract electroreceptive predators. To minimize costs, some nocturnally active electric fish rapidly boost the ...

    Abstract Electric fish generate and sense electric fields for navigation and communication. These signals can be energetically costly to produce and can attract electroreceptive predators. To minimize costs, some nocturnally active electric fish rapidly boost the power of their signals only at times of high social activity, either as night approaches or in response to social encounters. Here we show that the gymnotiform electric fish Sternopygus macrurus rapidly boosts signal amplitude by 40% at night and during social encounters. S. macrurus increases signal magnitude through the rapid and selective trafficking of voltage-gated sodium channels into the excitable membranes of its electrogenic cells, a process under the control of pituitary peptide hormones and intracellular second-messenger pathways. S. macrurus thus maintains a circadian rhythm in signal amplitude and adapts within minutes to environmental events by increasing signal amplitude through the rapid trafficking of ion channels, a process that directly modifies an ongoing behavior in real time.
    Keywords Biology (General) ; QH301-705.5
    Language English
    Publishing date 2009-09-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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