Thrips in vegetables begin life as an egg, inserted into the host
plant's tissue (Terebrantia), or attached to the plant surface
(Tubulifera). After two "larval"
instars, which are important to
feeding stages, the insect goes
through two non-feeding "pupal"
instars. The pupal stages are usually spent in or on the soil.
While these are not true larvae or pupae, these terms are commonly
used to describe the immature stages in a thrips life cycle. The
immature stages vary in length, depending on climate and other
factors.
An adult emerges from the last pupal stage. Mating occurs shortly
after emergence. In some species,
males may congregate around flowers where females come to feed.
In many species, females are capable of producing viable offspring
without mating, and males are rare. In species where males are
more common, the ratio of males to females is variable, but females
generally are more common.
Some species of thrips are highly host-specific.
Many of the Phlaeothripidae are fungal feeders. A few species
in both the Terebrantia and Tubulifera
are predaceous, and can have a significant
impact on mites and insects in
some crops. The thrips species that feed on vegetable crops tend
to be generalists, and infest many
hosts.