a 30-something woman, a long-term relatively high-status member of the club, interrupting the lectures every few minutes with some "witty" remark.

Not sure what you mean by "witty remark", but wit and humor often connote fairly high status, as opposed to, e. g. just giggling at something or other things you mentioned. Could it be that your girlfriend was just annoyed at the sheer amount of interruptions? And yes, there may have been some intra-gender status competition involved, but males often compete in much the same way (Protip: don't invite sealion specimens at clubs or conferences).