Pollen DNA barcoding networks which are made up of all the interactions between plants and the animals that facilitate their pollination. Identifying the pollen carried on insects helps scientists understand what plants are being visited by which insects. Insects can also have homologous features making them difficult to identify and are themselves sometimes identified through genetic barcoding (usually of the CO1 region). Every insect that visits a flower isn’t necessarily a pollinator. Many lack features such as hairs allowing them to carry pollen while others avoid the pollen-laden anthers to steal nectar. Pollination networks are made more accurate by including what pollen is
Pollen tube grains are deposited in the micropyle of the ovule of a female cone or megastrobilus, where they mature for up to a year. In conifers and Gnetophytes the pollen germinate to produce a pollen tube that penetrates the megasporangium or nucellus carrying with it sperm nuclei that are transferred to the egg cell in the developing archegonia of the female plant. The female sporophyte must recognize the pollen stuck to the stigma. Often, only pollen of the same species can successfully grow and outcrossed pollen is more successful in growing. With self-incompatibility systems, outcrossed pollen grows and outcompetes self pollen.