I'd be careful about making such hard-fast statements. I have never seen a male garter eat a female, but I have seen many instances of animals eating animals larger then themselves; often times with both animals dying. My newt ate a algae eater that was larger then it... regurged it a day later. If you google salamander eating centipede, you might find a photo showing a larger centipede that had just been regurged from the sal. with the stress of capture. Kingsnakes often eat snakes longer and perhaps occasionally larger then themselves, the prey being folded upon itself to fit it in. Is anything like this likely in your captive enclosure... no. Does it really matter if the male eats the female or the female eats the male... no, either way = sad keeper.

Ian