Mechanism of facultative parthenogenesis in the ant Platythyrea punctata

Abstract

Thelytokous parthenogenesis, the production of diploid female offspring from unfertilized eggs, can be caused by several cytological mechanisms, which have a different impact on the genetic variation on the offspring. The ponerine ant Platythyrea punctata is widely distributed throughout the Caribbean Islands and Central America and exhibits facultative parthenogenesis. Workers in many field colonies from the Caribbean Islands have identical multilocus genotypes and are thus probably clonal, but the occurrence of males makes an ameiotic mechanism of thelytoky unlikely. To clarify the details of thelytoky in this species we compared the multilocus genotypes of mothers and their offspring in experimental colonies and analyzed the genotypes of haploid and diploid males. Additionally, we screened a large number of field colonies from thelytokous populations for the occurrence of recombination events. According to these data, automixis with central fusion and a reduced recombination rate is the most likely mechanism of thelytoky, as in the Cape honeybee and the ant Cataglyphis cursor.