In the wild, males are usually at their prime physical state during musth and ordinarily do most of the breeding.
Once released, the males would have to live long enough to impregnate females, and they would need to be healthy enough to compete with wild males for the right to do so.
Sure enough, the females always preferred wild males' courtships, whether cloaked in green or not.
Generally, the sterilising process weakens the males so much that they struggle to mate; the wild males are dominant.
First generation (F1) progeny were created by crossing both hatchery and wild females with hatchery and wild males to create hybrid and control lines.
Transgenic males also face a postcopulatory reproductive disadvantage as their ejaculates contained fewer sperm that swam slower and for shorter durations than sperm from wild males.
In the wild, males mate with females almost constantly, to guard against sneaky males that might try to fertilize some eggs for themselves.
Pheromone-baited delta traps were laid out in transects across a commercially important citrus-producing valley to assess the spatial and temporal distribution of wild males, prior to implementation of a commercial SIR programme.
Sperm from wild males of L. occidentalis reacted against conspecific EW, but at a low rate, suggesting that further maturation may be required in the external surface of the thelycum.
And to make sure his laboratory experiment accurately reflected what happened in nature, Delia stayed up night after night near a remote stream in Colombia monitoring 18 wild males and their clutches.
The GM males made up 16% of males in the study area, and fathered 10% of the larvae; so they were not quite as successful as the wild males, but not significantly worse.
