How can plants pollinate themselves when few pollinators are available?

When pollinators are scarce, plants can employ several strategies to ensure reproduction through self-pollination or asexual processes.

Mechanisms for Self-Pollination

Many plants are self-compatible, allowing their own pollen to fertilize their flowers. When pollinators are unavailable, plants may use the following methods to facilitate this:
* Physical Movement: Some plants physically move their reproductive parts to ensure contact. For example, stamens or styles may curve to touch one another, or the flower may physically twist to bring the pollen to the stigma.12
* Chemical and Fluid Aids: Some species use oils to slide pollen from the anther to the stigma or liquefy the pollen to facilitate its movement.2
* Cleistogamy: Certain plants are cleistogamous, meaning their flowers never open, which forces self-pollination by keeping the reproductive parts enclosed.12

Asexual Reproduction

Some plants bypass fertilization entirely through apomixis, a process where seeds develop without the need for sperm and egg fusion. This allows plants to produce offspring that are genetically identical to the parent, ensuring survival in stable environments where pollinators may be absent.13

While these methods are effective for survival, they often result in lower genetic variability compared to cross-pollination, which is why many plants treat selfing as a "last resort" when outbreeding is not possible.142