Clonal reproduction by males of the ant Vollenhovia emeryi (Wheeler)

Abstract

In colonies of the queen-polymorphic ant Vollenhovia emeryi, some colonies produce only long-winged (L) queens, while others produce only short-winged (S) queens. At four nuclear microsatellite loci, males in the S colony had alleles that were different from those of their queen. This suggests that the nuclear genome of males is not inherited from their colony queen, as has also been described for Wasmannia auropunctata (Roger). In V. emeryi the possibility of male transfer from other colonies has not been ruled out because previous studies of this species have obtained only nuclear gene information. We analyzed both mitochondrial and nuclear genes for S queens, S males and L queens to clarify the origins of males. Sequence analyses showed that although S queens and S males shared the same mtDNA haplotype, they had a different genotype at a nuclear gene (long-wavelength opsin) locus. Neighbor-joining analysis based on the four microsatellite loci also suggested gene pool separation between S queens and S males. These results are consistent with predictions of clonal reproduction by males. While L queens share opsin genotypes with S males, they have very different mtDNA sequences. Hybridization in the near past between S queens and L males or gene transmission from S males to L queen populations in the present would explain these differences.

Large-scale distribution of hybridogenetic lineages in a Spanish desert ant

“…Remarkably, a form of hybridogenesis at the social level has been reported in some ant species [5][6][7][8][9][10][11][12][13]. The hallmark of ant societies is reproductive division of labour based on a system of caste differentiation.…”

“…Because males of Hymenoptera arise from unfertilized haploid eggs by arrhenotokous parthenogenesis, they belong to the queen lineage. Another type of dependent-lineage system has been reported in Vollenhovia emeryi [6], Paratrechina longicornis [5] and invasive populations of Wasmania auropunctata [7]. In these species, reproductives develop from eggs with a single genome: new queens are clones of their mothers, whereas males are clones of their fathers.…”

Androgenesis: where males hijack eggs to clone themselves

“…In the little fire ant, W. auropunctata, workers arise sexually, queens arise by thelytoky, and males arise androgenetically [9,11,51]. It is tempting to regard this situation as a classic evolutionary arms race in which males retaliate against the absence rstb.royalsocietypublishing.org Phil.…”

“…Androgenesis has evolved independently in at least three ant species: Wasmannia auropunctata (the little fire ant) [9], Vollenhovia emeryi [10,11] and Paratrechina longicornis (the longhorn crazy ant) [12]. In all these species, sterile workers are produced via normal sexual reproduction involving queens and males.…”

“…As we explain in the following sections, whether and how diploidization occurs, and under which form of sex determination, greatly affects the predicted fate of androgenetic lineages. While androgenesis is rare in nature, it is 'normal' in some natural populations, including clams of the genus Corbicula [3][4][5], a conifer [6][7][8], a few ants [9][10][11][12] and stick insects [13][14][15][16], and most likely an Australian carp gudgeon [17] (table 1). Androgenesis is also seen sporadically in some species, particularly hymenopterans (ants, bees and wasps), and in some monocots, dicots and gymnosperms (table 1).…”