Polyembryony Among Abietineae

Polyembryony in Armadillos

O travelers passing through the southern US. may be struck by the unusual appearance of the ninebanded armadillo (Dasypus novemcinctus). This animal, which is about threequarters of a meter long, canbe identified by the leathery plates of armor that cover it nearly from the tip of its nose to the end of its tail. It also has a seriesof transverse plates that wrap around its midsection, giving i...

Polyembryony in Hierochloe Odorata (l.) Beauv

The evolution of polyembryony in parasitoid wasps.

Polyembryony has evolved independently in four families of parasitoid wasps. We review three main hypotheses for the selective forces favouring this developmental mode in parasitoids: polyembryony (i) reduces the costs of egg limitation; (ii) reduces the genetic conflict among offspring; and (iii) allows offspring to adjust their numbers to the quality of the host. Using comparative data and ve...

Paradoxical polyembryony? Embryonic cloning in an ancient order of marine bryozoans.

Prolific polyembryony is reported in few major taxa, but its occurrence has generated theoretical debate on potential conflict between sexual and asexual reproduction. It is, therefore, important to genetically confirm a widely cited inference, based on microscopy, that polyembryony characterizes marine bryozoans of the order Cyclostomata. Microsatellite genotyping of brooded embryos and matern...

Polyembryony in parasitic wasps: evolution of a novel mode of development.

Major developmental innovations have been associated with adaptive radiations that have allowed particular groups of organisms to occupy empty ecospace. Well-known developmental novelties associated with the conquest of new habitats include the evolution of the tetrapode limb, allowing the radiation of vertebrates into a terrestrial habitat, and formation of insect wings that permitted their di...