Tuesday, February 27, 2007
Zoo Animals
Well good news is that I picked up some juvenile virgin males at the zoo. Now I am waiting for some juveniles to molt. Basically, I have 8 virgin females and I have 16 males. Soon, I should be able to run one trial run. I will mate two sterile males to one female. Then I will vary the number of intromissions allowed which will be a 1 to 5 first to second male ratio. Then I will do the same two manipulations for the other groups (the 1st sterile, 2nd fertile & 1st fertile, 2nd sterile & 1st fertile, 2nd fertile). Then I should have some data hopefully. The idea is to be able to manipulate number of sperm so that we can control priority pattern. Usually, in this species, the first male has the advantage because he plugs up the female. However, we are not allowing the male to form a plug. Therefore, if there is sperm mixing going on in the female's spermatheca (storage sac), then we should be able to influence the priority pattern. We also sat down and dissected a female the other day and the storage sac is perfectly round, which would seem to facilitate sperm mixing. The other hypothesis is that priority pattern is determined by placement of sperm (location in the spermatheca). I am excited and hope that this first run goes well.
Busy,
ReplyDeleteHey! Good luck with the spiderlings!
It's great that you might be able to have data from a current study to analyze for your project! It makes it so much more meaningful because you actually have a vested interest in the analysis.
Happy Spider Mating!
Cheers,
Rebecca
Good luck!
ReplyDeleteDo you think the female spiders can "select" which sperm fertilizes their eggs in any way? Years ago I worked with squirrels, and though the males would insert plugs (like your spiders), the females could remove the plugs and "scoop out" sperm of a male they - for whatever reason - chose not to allow to father their young. Pretty weird - and interesting - stuff! Keep us up to date.
Cheers,
Nicole
I think that some female spiders can select the sperm that is fertilizing their eggs. In some species, females have to capicitate(some sort of chemical activation) the sperm in order to utilize them, which could definitely be a selection. Also, for some spiders the sperm storage sac may have two or multiple lobes. It would not be a stretch to say that these females parcel out the sperm from different males.
ReplyDeleteAnywho, for my spiders, I think that based on the circular structure of the spermatheca, there is sperm mixing going on. It is likely that the number of sperm are influencing paternity kind of like a lottery. At least, this is what I hope to show. In my species, there is undoubtedly guarding of penultimate females (juveniles who only need to molt once more before becoming sexually mature) by males. The males are probably competing for this spot since there is a first male advantage and a female could be practing choice because she could easily chase away an unwanted male due to her larger size!