エネルギー収支と繁殖戦略

All living things have a limited energy budget. They must divide their available energy among three main tasks: growth, maintenance, and reproduction.

Because energy is limited, organisms face trade-offs. Using more energy for one function leaves less energy for the others. These trade-offs shape an organism’s life history, including how fast it grows and when and how often it reproduces.

One reproductive strategy is semelparity. In semelparous species, an organism uses most of its stored energy in a single reproductive event and then dies.

The agave plant is a classic example. It grows for many years, stores energy, and then produces a large number of seeds at once.

Each seed contains relatively little stored energy, so many do not survive. However, producing many seeds increases the chance that some will survive.

Another strategy is iteroparity. Iteroparous species reproduce multiple times during their lives.

For example, a hare produces several litters over many years. Instead of investing all its energy at once, the hare divides its energy among repeated reproductive cycles.

These species often invest more energy in each offspring through parental care. This investment can incr