The sexual reproduction of Aspergillus involves a complex life cycle that includes both teleomorphic (sexual) and anamorphic (asexual) stages, collectively known as the holomorph. A key feature of the teleomorph is the dikaryon, formed when sexually compatible nuclei from different mycelia fuse through anastomosis but do not immediately combine into a diploid zygote. Instead, they develop into dikaryotic hyphae, where each cell contains two haploid nuclei. These nuclei eventually fuse to create diploid nuclei, followed by meiosis, allowing for genetic recombination. The teleomorphic stage has been observed in some, but not all, of the over 185 Aspergillus species, indicating that while evidence may be lacking for certain species, the potential for sexual reproduction exists across the genus.