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Sperm competition is a postcopulatory sexual selection mechanism in species in which females mate with multiple males. Despite its evolutionary relevance in shaping male traits, the genetic mechanisms underlying sperm competition are poorly understood. A recently originated multigene family specific to Drosophila melanogaster, Sdic, is important for the outcome of sperm competition in doubly mated females, although the mechanistic nature of this phenotype remained unresolved. Here, we compared doubly mated females, second mated to either Sdic knockout or nonknockout males, and directly visualize sperm dynamics in the female reproductive tract. We found that a less effective removal of first-to-mate male's sperm within the female's sperm storage organs is consistent with a reduced sperm competitive ability of the Sdic knockout males. Our results highlight the role young genes can play in driving the evolution of sperm competition.
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http://dx.doi.org/10.1111/evo.13417 | DOI Listing |
Insect Sci
September 2025
Department of Entomology & Nematology, University of Florida, Gainesville, Florida.
The sterile insect technique (SIT) is a highly effective biologically-based method for the suppression of many insect pest populations. SIT efficacy could be improved by methods of male sterilization that avoid the use of irradiation that can result in diminished fitness and mating competitiveness. Alternative sterilization methods include conditional disruption of genes for male fertility, or using their sperm-specific promoters to drive the expression of genes for lethal effectors.
View Article and Find Full Text PDFPLoS One
September 2025
Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, Valencia, Spain.
The genitalia of Lepidoptera are complex structures that evolve rapidly and divergently. The endophallus of many lepidopterans is ornamented with elaborate sclerotized structures known as cornuti. In some species, the cornuti are deciduous and remain within the female genital tract after copulation; the function of these structures is virtually unknown.
View Article and Find Full Text PDFJ Anim Ecol
September 2025
Centre for Ecology, Evolution, and Conservation, School of Biological Sciences, University of East Anglia, Norwich, UK.
Inbreeding and the associated increase in homozygosity and potential accumulation of deleterious alleles may reduce fitness in a process known as inbreeding depression. Mechanisms to mitigate reproduction between close relatives, ranging from pre-mating mate choice to post-mating gamete selection, have evolved across taxa. In external fertilisers like Atlantic salmon (Salmo salar), where females have limited control over paternity, mechanisms of inbreeding avoidance can be expected to evolve at the gamete level.
View Article and Find Full Text PDFMethods Protoc
August 2025
Department of Veterinary Sciences, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, 165 00 Prague, Czech Republic.
The initial molecular events mediating mammalian sperm binding to the zona pellucida (ZP) of the oocyte are highly complex and still not fully elucidated. Recent advances have identified multiple candidate sperm surface proteins, often functioning as part of high-molecular-weight complexes that mediate this critical fertilization event in a species-specific and coordinated manner. To address a significant gap in the literature, we provide an in-depth overview of the functional assays employed to investigate sperm-ZP interactions, emphasizing their underlying principles, potential applications, and key methodological strengths and limitations.
View Article and Find Full Text PDFProc Biol Sci
August 2025
Department of Anthropology, Tulane University, New Orleans, LA, USA.
Male reproductive success is determined by the interplay of female mate choice and male-male competition, often linked to dominance rank in social animals. Across taxa, elaborate ornaments, such as bright coloration or large antlers, often function as badges of status, signalling male competitive ability to rivals. In species where females mate with multiple males, post-mating sperm competition also plays an important role in male reproductive success and is associated with larger relative testes size.
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