Environmental cues that influence the timing of reproduction generally do so by .

Direct effects on the hormonal control mechanism.

Explanation:

The rate of reproduction is affected by the change in the hormonal control mechanism of the body. The timing of reproduction is affected by the hormonal levels in the body.

The early release of the hormones can be the reason for early reproduction whereas the delay in the release of the hormones can generally delay the time of reproduction.

This is how the timing of reproduction can be controlled in the organism.