Complex sentence: Individuals may also have a conditional behavior strategy that depends not on the genetic or developmental impact on one's life circumstance, but on external factors such as the number of available mates, or the number of nearby competitors and their employed tactics.
Split into simpler sentences: Individuals may also have a conditional behavior strategy that depends not on the genetic or developmental impact on one's life circumstance, but on external factors. These may include the number of available mates, or the number of nearby competitors and their employed tactics.