Post-natal development of the electromotor system in a pulse gymnotid electric fish

Pereira, Ana Carolina; Rodríguez-Cattáneo, Alejo; Castelló, María E.; Caputi, Ángel A.

doi:10.1242/jeb.000638

Cited by 15 publications

(14 citation statements)

References 49 publications

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“…It is therefore tempting to speculate that the origin of quasi-monophasic adult EODs in G. obscurus involved paedomorphic retention of an ancestral larval EOD. However, drum-shaped, double innervated electrocytes are clearly present in quasi-monophasic larval G. omarorum (Pereira et al, 2007), indicating that double innervation is expressed earlier in ontogeny than the appearance of multiphasic waveforms. If doubleinnervated electrocytes are present in larvae from all Gymnotus species, this would definitely rule out paedomorphic retention of mono-innervated electrocytes as an explanation for quasimonophasy in G. obscurus.…”

Section: Morpho-functional Group IVmentioning

confidence: 96%

“…In the electrosensory modality, EODs may attract passively electroreceptive predators, notably catfishes and Electrophorus, which possess ampullary electroreceptors that are maximally sensitive to low-frequency energy (LFE) at around 0-0.03kHz. The EODs of larval Gymnotus are quasi-monophasic (Crampton and Hopkins, 2005;Crampton et al, 2011;Pereira et al, 2007), and are dominated by LFE in the range sensitive to ampullary electroreceptors (see Fig.9A), but except for species belonging to ht-EOD category 4, these conspicuous EODs are transformed early in development into multiphasic EODs. The appearance of a large negative phase following the P 1 (V 3 ) phase elevates the PPF, and suppresses the contribution of LFE to the signal.…”

Section: Biotic Selection Pressures On Gymnotus Signals Predator Avoimentioning

confidence: 99%

“…All known larval Gymnotus generate quasi-monophasic category 4 ht-EODs (Crampton and Hopkins, 2005;Crampton et al, 2011;Pereira et al, 2007). It is therefore tempting to speculate that the origin of quasi-monophasic adult EODs in G. obscurus involved paedomorphic retention of an ancestral larval EOD.…”

Section: Morpho-functional Group IVmentioning

confidence: 99%

“…At the same time, the net DC component of the ht-EOD, which is also conspicuous to electroreceptive predators, is suppressed by balancing the positive and negative components of the signal until the net current between the curve of the ht-EOD waveform and 0V is close to zero. By these two mechanisms the transition from quasi-monophasic to multiphasic signals 'cloaks' LFE (Stoddard, 1999;Stoddard and Markham, 2008) at a stage where the EOD amplitude is rapidly increasing with body size (Pereira et al, 2007). Stoddard (Stoddard, 1999) hypothesized that selection from electroreceptive predators accounts for both the early ontogenetic transition to multiphasic signals observed in most pulse-generating gymnotiforms, and also the evolutionary origins of multiphasic signals from a plesiomorphic monophasic adult condition; note, however, that the phylogenies of Lovejoy et al (Lovejoy et al, 2010) and Arnegard et al (Arnegard et al, 2010b) do not support the notion of an ancestral monophasic EOD.…”

Section: Biotic Selection Pressures On Gymnotus Signals Predator Avoimentioning

confidence: 99%

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Proximate and ultimate causes of signal diversity in the electric fishGymnotus

Crampton

Rodríguez-Cattáneo

Lovejoy

et al. 2013

Journal of Experimental Biology

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SummaryA complete understanding of animal signal evolution necessitates analyses of both the proximate (e.g. anatomical and physiological) mechanisms of signal generation and reception, and the ultimate (i.e. evolutionary) mechanisms underlying adaptation and diversification. Here we summarize the results of a synthetic study of electric diversity in the species-rich neotropical electric fish genus Gymnotus. Our study integrates two research directions. The first examines the proximate causes of diversity in the electric organ discharge (EOD) -which is the carrier of both the communication and electrolocation signal of electric fishes -via descriptions of the intrinsic properties of electrocytes, electrocyte innervation, electric organ anatomy and the neural coordination of the discharge (among other parameters). The second seeks to understand the ultimate causes of signal diversity -via a continent-wide survey of species diversity, species-level phylogenetic reconstructions and field-recorded headto-tail EOD (ht-EOD) waveforms (a common procedure for characterizing the communication component of electric fish EODs). At the proximate level, a comparative morpho-functional survey of electric organ anatomy and the electromotive force pattern of the EOD for 11 species (representing most major clades) revealed four distinct groups of species, each corresponding to a discrete area of the phylogeny of the genus and to a distinct type of ht-EOD waveform. At the ultimate level, our analyses (which emphasize the ht-EOD) allowed us to conclude that selective forces from the abiotic environment have had minimal impact on the communication component of the EOD. In contrast, selective forces of a biotic nature -imposed by electroreceptive predators, reproductive interference from heterospecific congeners, and sexual selection -may be important sources of diversifying selection on Gymnotus signals.

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Section: Morpho-functional Group IVmentioning

confidence: 96%

Section: Biotic Selection Pressures On Gymnotus Signals Predator Avoimentioning

confidence: 99%

Section: Morpho-functional Group IVmentioning

confidence: 99%

Section: Biotic Selection Pressures On Gymnotus Signals Predator Avoimentioning

confidence: 99%

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Proximate and ultimate causes of signal diversity in the electric fishGymnotus

Crampton

Rodríguez-Cattáneo

Lovejoy

et al. 2013

Journal of Experimental Biology

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“…carapo, we named phases V2, V3, and V4 as P1, P2, and P3, to maintain consistent nomenclature with the other species (Pereira et al, 2007). amplitude response.…”

Section: Phenotypic Independence and Integration Asmentioning

confidence: 99%

Endocrine Regulation of Dynamic Communication Signals in Gymnotiform Fish

Goldina¹

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between an inconspicuous signal that evades predators and an extravagant signal preferred by females. Such a signal has been described in the gymnotiform electric fish, Brachyhypopomus gauderio, which produces a sexually dimorphic electric organ discharge (EOD). The EOD varies on a circadian rhythm and in response to social cues. This signal plasticity is mediated by the slow action of androgens and rapid action of melanocortins.My dissertation research tested the hypotheses that (1) signal plasticity is related to sociality levels in gymnotiform species, and (2) differences in signal plasticity are regulated by differential sensitivity to androgen and melanocortin hormones. To assess the breadth of dynamic signaling within the order Gymnotiformes, I sampled 13 species from the five gymnotiform families. I recorded EODs to observe spontaneous signal oscillations after which I injected melanocortin hormones, saline control, or presented the fish with a conspecific. I showed that through the co-option of the ancient melanocortin vii pathway, gymnotiforms dynamically regulate EOD amplitude, spectral frequency, both, or neither.To investigate whether observed EOD plasticities are related to species-specific sociality I tested four species; two territorial, highly aggressive species, Gymnotus carapo and Apteronotus leptorhynchus, a highly gregarious species, Eigenmannia cf. virescens, and an intermediate short-lived species with a fluid social system, Brachyhypopomus gauderio. I examined the relationship between the androgens testosterone and 11-ketotestosterone, the melanocortin α-MSH, and their roles in regulating EOD waveform.

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The Evolution and Development of Electric Organs

Gallant

2019

Electroreception: Fundamental Insights From Comparative Approaches

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Post-natal development of the electromotor system in a pulse gymnotid electric fish

Abstract: and the increase in amplitude of the discharge and (3) beyond 100·mm in length, when homothetic growth of the fish body explains the continuous increase in electric power of the discharge.

Cited by 15 publications

References 49 publications

Proximate and ultimate causes of signal diversity in the electric fishGymnotus

Proximate and ultimate causes of signal diversity in the electric fishGymnotus

Endocrine Regulation of Dynamic Communication Signals in Gymnotiform Fish

The Evolution and Development of Electric Organs

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