Sperm competition
- Social dominance, but not parasite load, affects sperm quality and sperm redox status in house sparrows
Summary: Immunity does not necessarily affect sperm performance or sperm and blood oxidative balance; however, social hierarchy and the relative soma/germline oxidative balance determine sperm performance.
- Seminal fluid enhances competitiveness of territorial males' sperm in a fish with alternative male reproductive tactics
Summary: Dynamics of ejaculate release may influence the role of seminal fluid in competitive contexts. In the black goby, where interaction between rival ejaculates is reduced, its function differs depending on male mating tactics.
- Microsurgical manipulation reveals pre-copulatory function of key genital sclerites
Summary: Insect genitalia are fashioned from numerous constituent parts but the function of individual components is poorly understood. Microsurgical manipulation reveals the parameres and end-plate to be crucial in securing copulation in Callosobruchus maculatus.
- Oxidative stress affects sperm performance and ejaculate redox status in subordinate house sparrows
Summary: Oxidative stress affects sperm velocity of low-ranked house sparrows.
- Ovarian fluid impacts flagellar beating and biomechanical metrics of sperm between alternative reproductive tactics
Highlighted Article: In Chinook salmon, sperm biomechanics may be driving divergence in competitive reproductive success between alternative reproductive tactics.
- Self-fertilization, sex allocation and spermatogenesis kinetics in the hypodermically inseminating flatworm Macrostomum pusillum
Summary: The flatworm Macrostomum pusillum is capable of self-fertilization, and its sexual biology suggests that this is a frequent or even the exclusive reproductive mode in this species.
- Sperm chemotaxis promotes individual fertilization success in sea urchins
Summary: Gamete traits, including sperm motility, play a strong role in sperm competition and fertilization; sperm chemotaxis promotes fertilization, and individual male fertilization correlates with sperm chemotactic behavior.
- Modification of sperm quality after sexual abstinence in Seba's short-tailed bat, Carollia perspicillata
Highlighted Article: A sexual abstinence experiment suggests that a difference in copulation frequency rather than an adaption to sperm competition provides Carollia perspicillata sneaker males with higher sperm quality than harem males.