Hormonal and behavioral correlates of morphological variation in an Amazonian electric fish (Sternarchogiton nattereri: Apteronotidae)

Fernandes, Cristina Cox; Smith, G. Troy; Podos, Jeffrey; Nogueira, Adília; Inoue, L. A. K. A.; Akama, Alberto; Ho, Winnie W.; Alves-Gomes, José Antônio

doi:10.1016/j.yhbeh.2010.06.006

Cited by 18 publications

(14 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Short-jawed and long-jawed P. hasemani males have androgen levels that are similar to each other and dissimilar from those of females. The hormone levels reported here are comparable to those seen among reproductively mature individuals in breeding condition in other species of weakly electric fish within the family Apteronotidae (Cox Fernandes et al, 2010; Dunlap et al, 1998; Ho et al, 2010). This hormonal evidence combined with previous descriptions of gonadal state among males of varying sizes indicates that both male types are reproductively competent and that short-jawed males are not simply immature long-jawed males (Cox Fernandes et al, 2002).…”

Section: Discussionsupporting

confidence: 81%

Androgens regulate sex differences in signaling but are not associated with male variation in morphology in the weakly electric fish Parapteronotus hasemani

Petzold

Smith

2016

Hormones and Behavior

Self Cite

View full text Add to dashboard Cite

Sexually dimorphic signaling is widespread among animals and can act as an honest indicator of mate quality. Additionally, differences in signaling and morphology within a sex can be associated with different strategies for acquiring mates. Weakly electric fish communicate via self-generated electrical fields that transmit information about sex, reproductive state, and social status. The weakly electric knifefish Parapteronotus hasemani exhibits sexual dimorphism in body size as well as substantial within-male variation in body size and jaw length. We asked whether P. hasemani exhibits hormonally mediated sexual dimorphism in electrocommunication behavior. We also asked whether males with short versus long jaws differed significantly from each other in morphology, behavior, hormone levels, or reproductive maturity. Males produced longer chirps than females, but other signal parameters (electric organ discharge frequency; chirp rate and frequency modulation) were sexually monomorphic. Pharmacologically blocking androgen receptors in males reduced chirp duration, suggesting that this sexually dimorphic trait is regulated at least in part by the activational effects of androgens. Males sorted into two distinct morphological categories but did not differ in circulating 11-ketotestosterone or testosterone. Short-jawed males and long-jawed males also did not differ in any aspects of signaling. Thus, chirping and high levels of 11-ketotestosterone were reliably associated with reproductively active males but do not necessarily indicate male type or quality. This contrasts with other alternative male morph systems in which males that differ in morphology also differ in androgen profiles and signaling behavior.

show abstract

Section: Discussionsupporting

confidence: 81%

Androgens regulate sex differences in signaling but are not associated with male variation in morphology in the weakly electric fish Parapteronotus hasemani

Petzold

Smith

2016

Hormones and Behavior

Self Cite

View full text Add to dashboard Cite

show abstract

“…In contrast, excreted 11KT concentrations were not correlated with EODf in male A. leptorhynchus housed in small social groups, although there was a trend for changes in 11KT induced by reduced conductivity to correlate positively with changes in EODf (Cuddy et al, 2012). In S. nattereri, reproductively mature males with external teeth have larger testes, higher levels of 11KT and higher EODf than reproductively mature males without teeth (Cox Fernandes et al, 2010). In contrast, 11KT levels are not correlated with EODf, size or jaw length in male P. hasemani and A. bonapartii, which have also have high within-sex morphological variation Petzold and Smith, 2012b).…”

Section: Hormonal Regulation Of Eodfmentioning

confidence: 71%

“…In S. nattereri, EODf differs between male morphs. Males with external teeth have higher EODf than females or reproductively mature males without teeth (Cox Fernandes et al, 2010). However, in P. hasemani, which has extreme within-and between-sex variation in head morphology, EODf is sexually monomorphic and does not differ between long-jawed and shortjawed males (Petzold and Smith, 2012b).…”

Section: Sex Differences In Eod Frequencymentioning

confidence: 99%

“…Although male apteronotids have plasma 11KT levels that are severalfold greater than those of females, females' testosterone levels are typically as high as those in males. This suggests that testosterone may serve as a hormone of reproductive condition in both sexes rather than as Zhou and Smith, 2006. a sex-specific hormone (Cox Fernandes et al, 2010;Ho et al, 2010;Petzold and Smith, 2012b).…”

Section: Hormonal Regulation Of Eodfmentioning

confidence: 99%

“…Sternarchogiton nattereri males that have external teeth, which are used in male-male aggression, have higher EODf than males without teeth (Cox Fernandes et al, 2010). However, in male P. hasemani, EODf is not significantly correlated with body size, and males with long jaws do not differ in EODf from males with short jaws (Petzold and Smith, 2012b).…”

Section: Eodf As An Intrasexual Signal Of Social Rankmentioning

confidence: 99%

See 2 more Smart Citations

Evolution and hormonal regulation of sex differences in the electrocommunication behavior of ghost knifefishes (Apteronotidae)

2013

Journal of Experimental Biology

Self Cite

View full text Add to dashboard Cite

SummaryThe ghost knifefishes (family Apteronotidae) are one of the most successful and diverse families of electric fish. Like other weakly electric fish, apteronotids produce electric organ discharges (EODs) that function in electrolocation and communication. This review highlights the diversity in the structure, function and sexual dimorphism of electrocommunication signals within and across apteronotid species. EOD frequency (EODf) and waveform vary as a function of species, sex and/or social rank. Sex differences in EODf are evolutionarily labile; apteronotid species express every pattern of sexual dimorphism in EODf (males>females; males

show abstract

Social regulation of electric signal plasticity in male Brachyhypopomus gauderio

2013

View full text Add to dashboard Cite

In animal communication, the social context that elicits particular dynamic changes in the signal can provide indirect clues to signal function. Female presence should increase the expression of male signal traits relevant for mate-choice, while male presence should promote the enhancement of traits involved in male-male competition. The electric fish Brachyhypopomus gauderio produces a biphasic electric pulse for electrolocation and communication. Pulse amplitude predicts the signaler's body size while pulse duration predicts circulating androgen levels. Males enhance pulse amplitude and duration when the numbers of males and females increase simultaneously. Here we tested the relative effects of female presence and male presence on male signal enhancement, and whether the size of the male competitor affected this enhancement. We found that male presence drives the enhancement of both pulse amplitude and second phase duration, independently of the size of the male competitor. Female presence induces the enhancement of pulse duration, but not pulse amplitude. These data suggest that males probably attend to information about a competitor's body size coded by pulse amplitude and attend to aggressiveness coded by a competitor's pulse duration, both potential predictors of fight outcome. Females may be primarily concerned about information on reproductive condition coded by pulse duration.

show abstract

Hormonal and behavioral correlates of morphological variation in an Amazonian electric fish (Sternarchogiton nattereri: Apteronotidae)

Cited by 18 publications

References 46 publications

Androgens regulate sex differences in signaling but are not associated with male variation in morphology in the weakly electric fish Parapteronotus hasemani

Androgens regulate sex differences in signaling but are not associated with male variation in morphology in the weakly electric fish Parapteronotus hasemani

Evolution and hormonal regulation of sex differences in the electrocommunication behavior of ghost knifefishes (Apteronotidae)

Social regulation of electric signal plasticity in male Brachyhypopomus gauderio

Contact Info

Product

Resources

About