ɪn hˌɛɾɚɹəθˈælɪk spˈiːsiːz, sˈɛkʃuːəl ɹᵻpɹədˈʌkʃən əkˈɜːz wɛn ˈɑːpəzˌɪt mˈeɪɾɪŋ tˈaɪps dˈɛzɪɡnˌeɪɾᵻd plˈʌs ænd kˈʌm ˌɪntʊ klˈoʊs pɹɑːksˈɪmᵻɾi, ɪndˈuːsɪŋ ðə fɔːɹmˈeɪʃən ʌv spˈɛʃəlˌaɪzd hˈaɪfiː kˈɔːld ɡˌæmɪtˈæŋɡiə.
In heterothallic species, sexual reproduction occurs when opposite mating types (designated + and -) come into close proximity, inducing the formation of specialized hyphae called gametangia.