A Mite Species That Consists Entirely of Haploid Females

Abstract

The dominance of the diploid state in higher organisms, with haploidy generally confined to the gametic phase, has led to the perception that diploidy is favored by selection. This view is highlighted by the fact that no known female organism within the Metazoa exists exclusively (or even for a prolonged period) in a haploid state. We used fluorescence microscopy and variation at nine microsatellite loci to show that the false spider mite, Brevipalpus phoenicis, consists of haploid female parthenogens. We show that this reproductive anomaly is caused by infection by an undescribed endosymbiotic bacterium, which results in feminization of haploid genetic males.

Cytogenetic mechanism and genetic consequences of thelytoky in the wasp Trichogramma cacoeciae

“…Among the different microorganisms that have been identified (Stouthamer et al, 1993;Weeks et al, 2001;Zchori-Fein et al, 2001), bacteria of the genus Wolbachia appear to be the most common parthenogenesis inducers. This symbiotic form of thelytoky can easily be distinguished from the thelytoky under direct control of the insect by its revertibility.…”

Feminization and the collapse of haplodiploidy in an asexual parasitoid wasp harboring the bacterial symbiont Cardinium

“…Wolbachia is a feminizer in two species with female heterogamety (Rigaud, 1997;Hiroki et al, 2002), and in a species with an XX/X0 sex determination system (Negri et al, 2006). Within haplodiploid arthropods, so far, feminization has been reported only for Cardinium in the asexual mite Brevipalpus where Cardinium feminizes unfertilized haploid eggs (Weeks et al, 2001;Chigira and Miura, 2005). This mechanism of feminization in Brevipalpus differs from that described here in E. hispida, where unusual diploid males are converted to females.…”

“…Recently, a high incidence (22%) has been detected in spiders (Araneae) (Duron et al, 2008). Like Wolbachia, in the a-Proteobacteria, Cardinium may cause manipulation of host reproduction in ways that increase its frequency within a host population, including feminization (genotypic males develop as functional phenotypic females) (Weeks et al, 2001), cytoplasmic incompatibility (Hunter et al, 2003;Gotoh et al, 2007) and thelytokous parthenogenesis (females produce only daughters from unfertilized eggs) (Zchori-Fein et al, 2001, 2004Provencher et al, 2005;Groot and Breeuwer, 2006;Matalon et al, 2007). Cardinium also increases the fecundity of a mite host (Weeks and Stouthamer, 2004).…”

Check out these males

“…Indeed, as stated in the title of the Giorgini et al (2009) study, Cardinium in E. hispida does not restore diploidy but acts as a feminizer of an already diploid product. Feminization has been attributed to Cardinium in a haplodiploid mite in a previous study (Weeks et al, 2001). Although a specific form of genomic imprinting has been suggested to play a role in sex determination in the chalcidoid wasp Nasonia vitripennis (Beukeboom et al, 2007), it is not known whether this mechanism occurs in most Chalcidoidea or whether antibiotic-induced males are always diploid.…”