Explaining the maintenance of sexual reproduction remains one of the greatest challenges in biology. The theoretical oddity of sex is based on at least three advantages that asexual organisms have over sexual ones: 1Asexuals, by not producing males, have a two fold advantage over sexuals, regarding the number of reproductive individuals; 2Sexuals have an evolutionary disadvantage over asexuals,...

In colonies of the honeybee Apis mellifera, the queen is usually the only reproductive female, which produces new females (queens and workers) by laying fertilized eggs. However, in one subspecies of A. mellifera, known as the Cape bee (A. m. capensis), worker bees reproduce asexually by thelytoky, an abnormal form of meiosis where two daughter nucleii fuse to form single diploid eggs, which de...

Asexual reproduction, including parthenogenesis in which embryos develop within a female without fertilization, is assumed to confer advantages over sexual reproduction, which includes a "cost of males." Sexual reproduction largely predominates in animals, however, indicating that this cost is outweighed by the genetic and/or ecological benefits of sexuality, including the acquisition of advant...

The distinctive oribatid mite family Eulohmanniidae has been known almost exclusively from the type species of Eulohmannia, E. ribagai (Berlese, 1910), which is widely distributed in northern Hemisphere where it inhabits fine humus, typically beneath forest litter and moss. We describe morphological ontogeny based primarily on material New York—supported by specimens Canada, Europe, Asia—and co...

Liriomyza huidobrensis, L. sativae and trifolii are polyphagous agromyzid leafminers that have recently arrived in Australia, posing a threat to Australian vegetable ornamental crops. Adventive endemic hymenopteran parasitoids of already present Australia should assist the management these invasive species. Neochrysocharis formosa (Hymenoptera: Eulophidae: Entedoninae) is an idiobiont endoparas...

The most common way animals reproduce is bisexuality, namely through the mixis of male and female gametes. Bisexual reproduction relies on the Mendelian mechanism, although several additional modes also occur. In turn, the Mendelian inheritance of genetic variability stands on the meiotic process, which entrains recombination and chromosome reshuffling within the frame of a balanced segregation...

A major component of the evaluation of biological control agents is the study and comparison of their biology, including the reproductive mode. In hymenopteran parasitoids, reproductive modes include thelytoky and arrhenotoky. Since a thelytokous population produces only females, it is assumed that they may be better suited for biological control than an arrhenotokous population. Here we compar...

In laboratory studies of fertilization using the gonochoric broadcast-spawning asterinid sea star Patiria miniata, we found many cases in which some mature eggs spawned by females formed cleavage-stage embryos and feeding bipinnaria larvae without fertilization by sperm. Segregation of maternal microsatellite alleles among the parthenogenetic offspring of known heterozygous females was consiste...