02359nas a2200157 4500008004100000022001400041245017700055210006900232260001600301300001600317490000800333520170900341100001602050700001502066856012002081 2008 eng d a0022-094900aFemale choice by electric pulse duration: attractiveness of the males' communication signal assessed by female bulldog fish, Marcusenius pongolensis (Mormyridae, Teleostei)0 aFemale choice by electric pulse duration attractiveness of the m cMar-06-2009 a1969 - 19770 v2113 a

In adult males of the South African weakly electric bulldog fish, Marcusenius pongolensis, the duration of the electric organ discharge (EOD) increases with body size over lifetime. Although there is experimental support for intrasexual selection (male–male competition) having shaped the males' EOD pulse duration in evolution, nothing is known about intersexual selection, such as female choice. Playback of 25 natural male EODs of pulse duration varying from 320 μs (close to the average female value) to 716μ s, to eight female experimental subjects elicited approach, head butts and circling behaviour. The rate of head butts on the dipole electrode model increased significantly with stimulus pulse duration in seven out of eight experimental subjects. In ten experimental female subjects we contrasted the shortest playback pulse with simultaneous playback of one of four longer ones (424, 524, 628 and 716 μs). Pooled responses for all experimental subjects were stronger for the dipole playing back the longer pulse in a pulse pair. The difference in the number of head butts (Δhead butts) that were dealt the two dipoles per 60 s test session increased significantly with the difference in pulse duration (Δpulse duration). The increase followed a significant linear trend (P<0.0001). Similar results were obtained for Δassociation time, Δcircles with head butts, andΔ circles without head butts. These results suggest that a male's reproductive success is enhanced by longer, i.e. more attractive EODs, and that both intra- and intersexual selection must have played a significant role in shaping the EOD of male M. pongolensis.

1 aMachnik, P.1 aKramer, B. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.016949https://syndication.highwire.org/content/doi/10.1242/jeb.01694902364nas a2200145 4500008004100000022001400041245013300055210006900188260001600257300001200273490000800285520184500293100002302138856005702161 2016 eng d a0022-094900aDifferences in electrosensory anatomy and social behavior in an area of sympatry between two species of mormyrid electric fishes0 aDifferences in electrosensory anatomy and social behavior in an  cApr-11-2016 a31 - 430 v2193 a

Sensory systems play a key role in social behavior by mediating the detection and analysis of communication signals. In mormyrid fishes, electric signals are processed within a dedicated sensory pathway, providing a unique opportunity to relate sensory biology to social behavior. Evolutionary changes within this pathway led to new perceptual abilities that have been linked to increased rates of signal evolution and species diversification in a lineage called ‘clade A’. Previous field observations suggest that clade-A species tend to be solitary and territorial, whereas non-clade-A species tend to be clustered in high densities suggestive of schooling or shoaling. To explore behavioral differences between species in these lineages in greater detail, I studied population densities, social interactions, and electric signaling in two mormyrid species, Gnathonemus victoriae (clade A) and Petrocephalus degeni (non-clade A), from Lwamunda Swamp, Uganda. Petrocephalus degeni was found at higher population densities, but intraspecific diversity in electric signal waveform was greater in G. victoriae. In the laboratory, G. victoriae exhibited strong shelter-seeking behavior and competition for shelter, whereas P. degeni were more likely to abandon shelter in the presence of conspecifics as well as electric mimics of signaling conspecifics. In other words, P. degeni exhibited social affiliation whereas G. victoriae exhibited social competition. Further, P. degeni showed correlated electric signaling behavior whereas G. victoriae showed anti-correlated signaling behavior. These findings extend previous reports of social spacing, territoriality, and habitat preference among mormyrid species, suggesting that evolutionary divergence in electrosensory processing relates to differences in social behavior.

1 aCarlson, Bruce, A. uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.12772000481nas a2200109 4500008004100000245017100041210006900212300001400281490000800295100002000303856004800323 1999 eng d00aSystematic biology of gymnotiform and mormyriform electric fishes: phylogenetic relationships, molecular clocks and rates of evolution in the mitochondrial rRNA genes0 aSystematic biology of gymnotiform and mormyriform electric fishe a1167-11830 v2021 aAlves-Gomes, J. uhttps://mormyrids.myspecies.info/en/node/6200426nas a2200121 4500008004100000245009400041210006900135260001200204300001100216490000800227100002100235856004800256 1992 eng d00aIndividual and sex specificity in the electric organ discharges of breeding mormyrid fish0 aIndividual and sex specificity in the electric organ discharges  c03/1992 a79-1020 v1641 aCrawford, J., D. uhttps://mormyrids.myspecies.info/en/node/6700546nas a2200145 4500008004100000245013800041210006900179300001200248490000800260653001500268100002300283700002400306700002200330856004800352 2000 eng d00aMolecular systematics of the African electric fishes (Mormyroidea: Teleostei) and a model for the evolution of their electric organs.0 aMolecular systematics of the African electric fishes Mormyroidea a665-6830 v20310aMormyridae1 aSullivan, John, P.1 aLavoué, Sébastien1 aHopkins, Carl, D. uhttps://mormyrids.myspecies.info/en/node/5900504nas a2200133 4500008004100000245012200041210006900163300001400232490000800246100002600254700002000280700002200300856004800322 2006 eng d00aTime-domain signal divergence and discrimination without receptor modification in sympatric morphs of electric fishes0 aTimedomain signal divergence and discrimination without receptor a2182-21980 v2081 aArnegard, Matthew, E.1 aJackson, B., S.1 aHopkins, Carl, D. uhttps://mormyrids.myspecies.info/en/node/4102925nas a2200169 4500008004100000022001400041245014800055210006900203260001200272300001600284490000800300520233300308100002302641700002202664700002102686856004802707 2012 eng d a1477-914500aDifferential expression of genes and proteins between electric organ and skeletal muscle in the mormyrid electric fish Brienomyrus brachyistius0 aDifferential expression of genes and proteins between electric o c07/2012 a2479 - 24940 v2153 a

Electric organs (EOs) have evolved independently in vertebrates six times from skeletal muscle (SM). The transcriptional changes accompanying this developmental transformation are not presently well understood. Mormyrids and gymnotiforms are two highly convergent groups of weakly electric fish that have independently evolved EOs: while much is known about development and gene expression in gymnotiforms, very little is known about development and gene expression in mormyrids. This lack of data limits prospects for comparative work. We report here on the characterization of 28 differentially expressed genes between SM and EO tissues in the mormyrid Brienomyrus brachyistius, which were identified using suppressive subtractive hybridization (SSH). Forward and reverse SSH was performed on tissue samples of EO and SM resulting in one cDNA library enriched with mRNAs expressed in EO, and a second library representing mRNAs unique to SM. Nineteen expressed sequence tags (ESTs) were identified in EO and nine were identified in SM using BLAST searching of Danio rerio sequences available in NCBI databases. We confirmed differential expression of all 28 ESTs using RT-PCR. In EO, these ESTs represent four classes of proteins: (1) ion pumps, including the - and -subunits of Na+/K+-ATPase, and a plasma membrane Ca2+-ATPase; (2) Ca2+-binding protein S100, several parvalbumin paralogs, calcyclin-binding protein and neurogranin; (3) sarcomeric proteins troponin I, myosin heavy chain and actin-related protein complex subunit 3 (Arcp3); and (4) the transcription factors enhancer of rudimentary homolog (ERH) and myocyte enhancer factor 2A (MEF2A). Immunohistochemistry and western blotting were used to demonstrate the translation of seven proteins (myosin heavy chain, Na+/K+-ATPase, plasma membrane Ca2+-ATPase, MEF2, troponin and parvalbumin) and their cellular localization in EO and SM. Our findings suggest that mormyrids express several paralogs of muscle-specific genes and the proteins they encode in EOs, unlike gymnotiforms, which may post-transcriptionally repress several sarcomeric proteins. In spite of the similarity in the physiology and function of EOs in mormyrids and gymnotiforms, this study indicates that the mechanisms of development in the two groups may be considerably different.

1 aGallant, Jason, R.1 aHopkins, Carl, D.1 aDeitcher, D., L. uhttps://mormyrids.myspecies.info/en/node/1602946nas a2200169 4500008004100000022001400041245014800055210006900203260001200272300001600284490000800300520235400308100002302662700002202685700002102707856004802728 2012 eng d a1477-914500aDifferential expression of genes and proteins between electric organ and skeletal muscle in the mormyrid electric fish Brienomyrus brachyistius0 aDifferential expression of genes and proteins between electric o c07/2012 a2479 - 24940 v2153 a

Electric organs (EOs) have evolved independently in vertebrates six times from skeletal muscle (SM). The transcriptional changes accompanying this developmental transformation are not presently well understood. Mormyrids and gymnotiforms are two highly convergent groups of weakly electric fish that have independently evolved EOs: while much is known about development and gene expression in gymnotiforms, very little is known about development and gene expression in mormyrids. This lack of data limits prospects for comparative work. We report here on the characterization of 28 differentially expressed genes between SM and EO tissues in the mormyrid Brienomyrus brachyistius, which were identified using suppressive subtractive hybridization (SSH). Forward and reverse SSH was performed on tissue samples of EO and SM resulting in one cDNA library enriched with mRNAs expressed in EO, and a second library representing mRNAs unique to SM. Nineteen expressed sequence tags (ESTs) were identified in EO and nine were identified in SM using BLAST searching of Danio rerio sequences available in NCBI databases. We confirmed differential expression of all 28 ESTs using RT-PCR. In EO, these ESTs represent four classes of proteins: (1) ion pumps, including the α- and β-subunits of Na(+)/K(+)-ATPase, and a plasma membrane Ca(2+)-ATPase; (2) Ca(2+)-binding protein S100, several parvalbumin paralogs, calcyclin-binding protein and neurogranin; (3) sarcomeric proteins troponin I, myosin heavy chain and actin-related protein complex subunit 3 (Arcp3); and (4) the transcription factors enhancer of rudimentary homolog (ERH) and myocyte enhancer factor 2A (MEF2A). Immunohistochemistry and western blotting were used to demonstrate the translation of seven proteins (myosin heavy chain, Na(+)/K(+)-ATPase, plasma membrane Ca(2+)-ATPase, MEF2, troponin and parvalbumin) and their cellular localization in EO and SM. Our findings suggest that mormyrids express several paralogs of muscle-specific genes and the proteins they encode in EOs, unlike gymnotiforms, which may post-transcriptionally repress several sarcomeric proteins. In spite of the similarity in the physiology and function of EOs in mormyrids and gymnotiforms, this study indicates that the mechanisms of development in the two groups may be considerably different.

1 aGallant, Jason, R.1 aHopkins, Carl, D.1 aDeitcher, D., L. uhttps://mormyrids.myspecies.info/en/node/17