February 11th, 2007
he or she?
Last night, Dave, left a comment on the Feeding a Butterfly post asking, “Do you know its sex? Have you given it a name yet?”. This morning, Wayne added his comment, “Good question, Dave. I was immediately thinking, next step: provide appropriate plant species for laying eggs. Cart before horse – is butterfly female? Can lepidopterans switch sexes? Can they produce fertile eggs through an asexual mechanism like parthenogenesis?”
So, here are some answers – hopefully accurate.
Q:: Is the recently eclosed butterfly a male or female?
A:: Above, I’ve posted two photos of Black Swallowtail (Papilio polyxenes) butterflies that I photographed last summer here at the farm (click on images for larger views). The top photo is a male. As you might notice, the inner band of yellow markings is quite distinctive, especially on the hind wings. The photo just below is a female that I photographed in late August. I caught that photo while the butterfly was taking a momentary break from egg-laying on the Queen Anne’s Lace plants in the garden. As you can see, it has fainter yellow markings – the hind wings being very differently marked than the male in the above photo. Here are another pair of male and female butterflies of this species from the Massachusetts Butterfly Club webpages (hopefully those links will work).
Based on its markings, I’d say that, beyond any doubt, our house guest is a male.
Now, on to the rest of the questions:
Q:: Have I given it (him) a name?
A:: No, but maybe we’ll call him Surprise, although when I’m trying to get him out from among some objects atop the bookshelves, I sometimes feel like calling him something else.
Q:: Can lepidopterans switch sexes? Can they produce fertile eggs through an asexual mechanism like parthenogenesis?
A:: Not that I’m aware of – and, no, I don’t think so. I know that people who breed moths will keep the female in some place where her scent will attract males. I haven’t read as much about butterfly breeding, but I’m assuming that males are required in order to fertilize eggs.
Q:: [What are the] appropriate plant species for laying eggs?
A:: Here at the farm, I usually see Black Swallowtails laying eggs on Queen Anne’s Lace (Daucus carota) plants. However, the above-mentioned Massachusetts Butterfly Club website provides a list of other members of the carrot family (Umbelliferae) which can provide food for larvae. At this time of the year, about all I could have done would be to purchase some dill or maybe buy some carrots with tops, and stick these in a jar of water. I’m not sure if the butterfly would have been too impressed!