Ejaculate testosterone levels affect maternal investment in red junglefowl (Gallus gallus gallus)

Abstract

Substantial concentrations of testosterone are not only present in a male’s circulation, but also in its ejaculate. Surprisingly, the regulation of ejaculate T and its effects on females and their offspring, potentially a cryptic paternal trait, are not known. We found lower circulating and higher ejaculate T concentrations in subordinate red junglefowl ( Gallus gallus gallus ) males compared to dominant males, suggestive of an adaptive trade-off in T allocation to circulation and their ejaculate. Subsequently, we artificially inseminated females with either testosterone enriched (TE) or control ejaculates (CE) in a cross-over design. TE females produced heavier eggs than CE females. Offspring growth and tonic immobility were affected in a sex-specific way by TE. TE sons were heavier with shorter TI duration than CE sons, and TE daughters were lighter than CE daughters but daughters did not differ in TI score. However, the chicks competitiveness was not influenced by the TE nor CE. This indicates a previously unknown function of ejaculate testosterone as well as a new form of interaction between a cryptic paternal trait and a maternal effect that may be widespread in the animal kingdom.

The relationship between male social status, ejaculate and circulating testosterone concentration and female yolk androgen transfer in red junglefowl (Gallus gallus)

“…The current study is based on our previous studies summarized in Table 1. In one previous study, (Lelono et al, 2019), we found that large-comb males are always winners in a confrontation with smallcomb males and after the social challenge have higher plasma T and lower ejaculates T compared to the subordinate males. However, whether these differences already existed before fight, for example related to the social status or physical characters such as body mass and comb size, or are due to winning or losing a fight remains to be tested.…”

Functional Aspects of Seminal Plasma in Bird Reproduction

“…The concentration of testosterone in seminal plasma was approximately two times less than in blood in both turkey [60] and chicken [61]. Seminal plasma testosterone concentration shows an inverse relationship with social status and blood plasma testosterone concentrations in red jungle fowl [62]. Testosterone concentrations in seminal plasma from ductus deferens and ejaculated seminal plasma are not significantly different [60,61].…”

Sperm Cryopreservation in American Flamingo (Phoenicopterus Ruber): Influence of Cryoprotectants and Seminal Plasma Removal

“…The seminal plasma is a complex mixture of proteins, free amino acids, lipids, carbohydrates, and hormones [ 5 , 20 , 21 , 22 , 23 , 24 ]. In the second experiment, it was decided to remove the seminal plasma because other studies reported a deleterious effect in the storage of semen samples of chicken and turkey [ 25 , 26 , 27 ].…”

“…In mammals, the seminal plasma may have some components that protect of cryoinjury and improve the sperm resistance to cold-shock damage [ 16 , 17 , 18 ], but in some species (e.g., goat) the seminal plasma removal is routine in sperm cryopreservation protocols, because contains components that reduces the chances of efficient sperm preservation [ 19 ]. Some of these components include proteins, ions, free amino acids, lipids, carbohydrates, polyamines, steroid hormones, and prostaglandins [ 5 , 20 , 21 , 22 , 23 , 24 ]. The role of seminal plasma on bird semen in vitro storage remains largely a matter of speculation as both inhibitory and stimulating effects have been found [ 20 ].…”