Asexual reproduction
From Memory Alpha, the free Star Trek reference.
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only.
Tribbles are bisexual (dual sexed) and are capable of reproducing at will. Born pregnant, and with sufficient food, a single tribble can breed in number exponentially, producing a litter of ten in twelve hours time. (TOS: "The Trouble with Tribbles")
Xindi-Insectoids reproduce asexually. (ENT: "Hatchery")
