Sexing Male and Female Giant Swallowtails

19 years ago

Posters on this forum have often asked how to tell male from female giant swallowtails. Well, today I saw a pair of GSTs mating on my picket fence, so I got out my camera, and they immediately flew off to a tree, still paired. I assume this was a male and female, but after seeing CalSherry's monarchs - hmmm........ it's just those Californians! :)

I chased them from tree to tree trying to get a good picture of them. This picture isn't too good, but it was as good as I could get considering how uncooperative they were! The female is the one on top, the male on the bottom - you'd think it'd be just the opposite, since it's the female receiving the sperm, but I've noticed this same arrangement with other butterflies. The female has a thin cross bar, the male a much thicker one, also the spots are bigger on the male - maybe you can see that from this picture -

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Here's another picture I took of the happy couple from the underside that I actually like better, unfortunately you can't see their bars or spots well enough to measure their size -

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I don't know if these were one of the 5 GSTs I released today, some I released before or a combination - I've released 34 over the past week.

MissSherry

Featured Answer

linda_centralokzn6

19 years ago

Thanks for the pics and Giant lessons, Miss Sherry. I will keep that in mind. :)

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Comments (7)

mboston_gw
19 years ago
Wow, DH just saw one trying to find a stem of my Wild Lime that she liked to lay on but I couldn't find any eggs. Then I just saw her a few minutes ago on the other side of the yard where my neighbor has a grapefruit tree and we have a tanegerine tree. If she lays on those I will never find the eggs - trees are too tall!

Great picture of the undersides!
christie_sw_mo
19 years ago
I can see the difference in your photo. I'll have to remember by thinking that the males are a little flashier like male birds sometimes are.
Looking back at my photos from April/May when mine emerged, I think I had two males and maybe one female or all three might have been males which would explain why I haven't found any babies on my rue or prickly ash. : (

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Male Giant Swallowtail (I think)
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tdogmom
19 years ago
Yeee-haaaw! :P LOVE the pictures, MissSherry! It is definitely interesting...I have also noticed that the male is often on the bottom and I joked with hubby about this unusual 'butterfly missionary position.' Hubby calls it the Australian Missionary Position. tee-hee!

I found a dead male in the garden yesterday morning and know for a fact it was NOT the one I had released since its tails were intact. I was sad but then thought, "Hey! I now have a male GST specimen to share." I bet he was trying to find a girlfriend in my backyard but all he could find were Monarchs...
MissSherry
Original Author
19 years ago
Mary, I have a step ladder in my garden for climbing the heights - of course, your tangerine might be 25' tall and too tall for any ladder.
Christie, the GST in your picture is a male for sure - his bar isn't quite as thick as some males' bars, but it's bigger than a female's bar, and his spots are real big.
Sorry about the dead GST, CalSherry - surely you'll get some more cats soon, although I don't know when you'll find time to raise them with all those monarchs! :)
MissSherry
kaboehm (zone 9a, TX USA)
11 years ago
Just learned tonight that 3rd spot from tip, on top row of spots, always has a large oval black spot in females and in males it is solid (or nearly solid) yellow. That should make it easier to tell them apart. All of my recent releases have been female.
Kristi
MissSherry
Original Author
11 years ago
Pretty picture!

Sherry