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Mating Types in Aspidisca sp. (Ciliophora, Hypotrichida): a Cluster of Cryptic Species
Author(s) -
DINI FERNANDO,
BRACCHI PAOLO,
GIANNÍ ALESSANDRO
Publication year - 1987
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1987.tb03165.x
Subject(s) - biology , mating type , mating , reproductive isolation , sibling species , species complex , taxon , evolutionary biology , zoology , ecology , genetics , phylogenetic tree , gene , population , demography , sociology
A mating‐type analysis was performed on 78 stocks of the marine hypotrich ciliate, Aspidisca sp., from a sufficient number of diverse geographic locations, some widely separated. Evidence is provided for the existence of a binary mating system in this “morphospecies.” The collected stocks have been challenged by the most rigorous criterion, namely breeding affinity in the laboratory, and have yielded at least four reproductively, not necessarily geographically, isolated groups that are in fact “biological species,” here referred to as “syngens.” Different syngens contain different pairs of mating types. Syngens are morphologically indistinguishable; hence Aspidisca sp. can be considered a conservative taxon comprising a number of “cryptic” or “sibling species.” Information is also presented about the mating behavior and the pattern of nuclear events at conjugation in Aspidisca sp. Search for soluble pheromones of the mating types gave only negative results. Hence, direct contact with potential partners is postulated to play a critical role in preparing individuals to mate. Mating reaction and mating which actually involves cross‐fertilization (conjugation, sensu stricto) are completely inhibited by 10 μg/ml cycloheximide, suggesting the necessity of protein synthesis for recognition and union in conjugation of potential partners.