THE PARADOX OF POLYEMBRYONY - A REVIEW OF THE CASES AND A HYPOTHESIS FOR ITS EVOLUTION

Animal polyembryony appears to be paradoxical because it clones an unp roven genotype at the expense of genetic diversity in a clutch. Howeve r, it is employed by at least 18 taxa in six phyla (excluding instance s of occasional twinning). Most polyembryony occurs in parasitic stage s or in other environments whose quality is not predictable by the mot her; in some instances, it compensates for a constraint on zygote numb er. We predict that polyembryony is likely to evolve when the offsprin g has more information regarding optimal clutch size than the parents.