While the females would be capable of reproducing at this time, I would advise giving them another year or two, as they sound a bit young and breeding early may leave them prone to problems during oviposition. Also, breeding animals at a young age can significantly shorten their reproductive years. I have said it time and again, Drys require a high degree of patience, as they grow quickly, but are slow to mature, harbor long gestation periods, even longer incubnation periods and babies, especially unicolor and yellow-tail babies can take, what seems to be, an eternity to start feeding on their own. I believe females should be a minimum of three years of age, preferably four, and at least 6' with good mass prior to any breeding attempts, though I have no problem using males that are a minimum of two years of age and large enough to not appear as a snack for the female. ;0)
As for your female D. couperi, while many have incurred success with a single copulation, most breeders (self included), prefer to allow the pair to copulate as long and as often as they show interest and one highly successful breeder I know of feels he has better results when his females have copulated successfully a minimum of three times...
Best regards,
Jeff

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Jeff Snodgres
University of Arkansas
snodgresjeffreys@uams.edu
501.603.1947