The following have been gleaned primarily from reviews of grant proposals and from questions asked at seminars.
Genetic identity is the key concept, regardless of the level of variation of natural populations .
Genetic identity is most rigorously established by demonstrating that parent and progeny are isogenic, and this, in turn, is most efficiently done by progeny testing field-caught individuals. These data do not rule out small amounts of outcrossing in these populations, but they are convincing evidence of clonality as a general rule. Granted that clonal reproduction has been demonstrated, the data could also be compatible with reproduction by some apomictic mode rather than self-fertilization. This has actually happened in some invertebrates which were initially thought to be self-fertilizing but turned out to be parthenogenetic instead. Syngamy and mendelian segregation have been demonstrated in R. marmoratus , and both are incompatible with gynogenesis.