02362nas a2200157   4500008004100000022001400041245017700055210006900232260001600301300001600317490000800333520170900341100001602050700001802066856012002084       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<p>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&ndash;male competition) having shaped the males&#39; 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 &mu;s (close to the average female value) to 716&mu; 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 &mu;s). 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 (&Delta;head butts) that were dealt the two dipoles per 60 s test session increased significantly with the difference in pulse duration (&Delta;pulse duration). The increase followed a significant linear trend (P&lt;0.0001). Similar results were obtained for &Delta;association time, &Delta;circles with head butts, and&Delta; circles without head butts. These results suggest that a male&#39;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.</p>
1 aMachnik, P.1 aKramer, Bernd  uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.016949https://syndication.highwire.org/content/doi/10.1242/jeb.01694902153nas a2200169   4500008004100000022001400041245015600055210006900211260001600280300000800296490000900304520155700313100001801870700002401888700001401912856005701926       2016                        eng d  a1175-532600aElectric organ discharges of South African Marcusenius species (Teleostei: Mormyridae) and their effectiveness as indicators of local species diversity0 aElectric organ discharges of South African Marcusenius species T  cMay-11-2018  a3670 v42003 a<p>Recent morphological and genetic studies have revealed two new species of snoutfish in South Africa, Marcusenius caudisquamatus and M. krameri, which had been confused with M. pongolensis, the South African bulldog fish. All known mormyriform fish are nocturnal and emit electric organ discharges (EODs) for communication that are characteristic for their species. This paper examines whether or not the EODs of these three closely-related South African species can be differentiated from each other. An EOD pulse of a bulldog fish consists of a head-positive phase P, followed by a head-negative phase N of short duration. We measured and compared six variables of the EOD pulse waveform for South African samples for the three species from different locations using MANOVA, ANOVA and Discriminant Analysis, with M. devosi from Kenya as an outgroup. The EOD waveforms, normalized to the same P-phase amplitude, varied significantly from each other in four variables, most strongly in the amplitude of the N phase and the duration of the P phase. In two species, M. devosi and M. krameri, there was no evidence of difference between sexes, in contrast to M. pongolensis and M. caudisquamatus whose male pulses were of longer duration. M. devosi and M. krameri were statistically significantly independent of each other and of any other group studied. By contrast, the M. pongolensis specimens from different locations showed a high degree of variability amongst each other, including significant separation, and overlap with M. caudisquamatus.</p>
1 aKramer, Bernd1 aMaake, Pholoshi, A.1 aGon, Ofer  uhttp://biotaxa.org/Zootaxa/issue/view/zootaxa.4200.3