Hi, Connie/Hurley. I would have sent you a private email, but I thought I'd share this with everyone, since I think my results are significant.
First, some background. Earlier this year (early summer), Connie and I discussed a possible way to prevent sperm retention. I wanted to breed two females (who had just laid their first clutches) to a different male than the ones I'd bred them to for their first clutches, and I wanted to improve my odds that the second clutches wouldn't be the result of sperm retention from the first breedings. Connie suggested that perhaps exposing the females (after they laid their first clutches, but before I bred them to a different male) to ambient heat of 90 degrees or a bit higher for a few hours might (theoretically) kill off any remaining retained sperm.
So, a few days after the two females laid their first clutches, I put them in small sterlite boxes in a small bathroom with a ceramic heater, and I heated up the bathroom to 92 degrees. I left the females in there (with a thermometer in one of the boxes, to make sure the temps inside the boxes actually reached 92 degrees, but no higher) for four hours. After their post-lay shed, I then bred them to a different male (different from the first males).
Here are my results:
Amel female (her first year to breed, so small clutches):
First clutch (when bred to a snow) -- 7 amels.
Second clutch (when bred to a ghost) -- 3 normals (four eggs went bad in incubation).
Normal female (het anery and hypo A):
First clutch (when bred to a ghost)-- 5 ghosts, 2 hypos, 3 anerys and 3 normals (13 total).
Second clutch (when bred to a different ghost) -- 2 ghosts, 2 hypos, 5 anerys and 2 normals (11 total).
The way I know that the second clutch from the normal female was sired by the second ghost male is that the two clutches have VERY different head patterns -- each clutch has its own distinctive head pattern, and the two different patterns are noticeably different from each other (I'll try to post photos later).
So, I think it's reasonable to conclude that exposing a female to ambient heat of about 90 degrees for a few hours after laying a clutch MAY indeed prevent sperm retention for a second clutch.
This has ramifications beyond second breedings to different males. For instance, if a breeder does not want a female to double-clutch at all (for whatever reason -- perhaps the female is too small or has gotten sick during her first pregnancy), this may be a way to prevent an undesired second clutch.
I realize that two test breedings are not enough to prove this theory, so I intend to try it again several times next year. However, I think my results so far are promising enough to share.
First, some background. Earlier this year (early summer), Connie and I discussed a possible way to prevent sperm retention. I wanted to breed two females (who had just laid their first clutches) to a different male than the ones I'd bred them to for their first clutches, and I wanted to improve my odds that the second clutches wouldn't be the result of sperm retention from the first breedings. Connie suggested that perhaps exposing the females (after they laid their first clutches, but before I bred them to a different male) to ambient heat of 90 degrees or a bit higher for a few hours might (theoretically) kill off any remaining retained sperm.
So, a few days after the two females laid their first clutches, I put them in small sterlite boxes in a small bathroom with a ceramic heater, and I heated up the bathroom to 92 degrees. I left the females in there (with a thermometer in one of the boxes, to make sure the temps inside the boxes actually reached 92 degrees, but no higher) for four hours. After their post-lay shed, I then bred them to a different male (different from the first males).
Here are my results:
Amel female (her first year to breed, so small clutches):
First clutch (when bred to a snow) -- 7 amels.
Second clutch (when bred to a ghost) -- 3 normals (four eggs went bad in incubation).
Normal female (het anery and hypo A):
First clutch (when bred to a ghost)-- 5 ghosts, 2 hypos, 3 anerys and 3 normals (13 total).
Second clutch (when bred to a different ghost) -- 2 ghosts, 2 hypos, 5 anerys and 2 normals (11 total).
The way I know that the second clutch from the normal female was sired by the second ghost male is that the two clutches have VERY different head patterns -- each clutch has its own distinctive head pattern, and the two different patterns are noticeably different from each other (I'll try to post photos later).
So, I think it's reasonable to conclude that exposing a female to ambient heat of about 90 degrees for a few hours after laying a clutch MAY indeed prevent sperm retention for a second clutch.
This has ramifications beyond second breedings to different males. For instance, if a breeder does not want a female to double-clutch at all (for whatever reason -- perhaps the female is too small or has gotten sick during her first pregnancy), this may be a way to prevent an undesired second clutch.
I realize that two test breedings are not enough to prove this theory, so I intend to try it again several times next year. However, I think my results so far are promising enough to share.
A good sign!