Diploid males, diploid sperm production, and triploid females in the ant Tapinoma erraticum

Abstract

Under complementary sex determination (CSD), females of Hymenoptera arise from diploid, fertilized eggs and males from haploid, unfertilized eggs. Incidentally, fertilized eggs that inherit two identical alleles at the CSD locus will develop into diploid males. Diploid males are usually unviable or sterile. In a few species, however, they produce diploid sperm and father a triploid female progeny. Diploid males have been reported in a number of social Hymenoptera, but the occurrence of triploid females has hardly ever been documented. Here, we report the presence of triploid females, diploid males, and diploid sperm (produced by diploid males and stored in queen spermathecae) in the ant Tapinoma erraticum. Moreover, we show variations in the frequency of triploids among female castes: Triploid females are more frequent among workers than virgin queens; they are absent among mated, reproductive queens. The frequency of triploid workers also varies between populations and between nests within populations.

Conservation Genetics of Neotropical Pollinators Revisited: Microsatellite Analysis Suggests That Diploid Males Are Rare in Orchid Bees

“…We nevertheless conclude that allozyme‐based studies of orchid bees are probably methodologically flawed due to allele misscoring, and that this flaw accounts for the differences between allozyme‐based studies and our microsatellite‐based study. More direct methods of assessing diploid male frequencies and including analysis of females, for example by karyotype analysis (Eltz et al 1998) or genome size estimation by flow cytometry (Aron et al 2005; Cournault and Aron 2009), are needed to support our microsatellite‐based conclusions.…”

“…Although bees are thought to possess slCSD (van Wilgenburg et al 2006), the presence of a different kind of sex determination in orchid bees could explain the observed low frequencies of 2N males. A parasitoid hymenopteran has recently been shown to possess multilocus CSD (mlCSD; de Boer et al 2008) and diploid males in hymenopterans with regular inbreeding produce fertile diploid males (de Boer et al 2007; Cournault and Aron 2009); in one wasp with regular inbreeding, diploid males may even produce haploid sperm (Cowan and Stahlhut 2004). Sex determination through genomic imprinting has also been recently demonstrated in the haplodiploid hymenopteran Nasonia (Verhulst et al 2010).…”

Fertile diploid males in the ant Cataglyphis cursor: a potential cost of thelytoky?

“…However, in colonies for which workers were sampled, the presence of alleles not found in the queen and in workers indicated a non-natal origin of haploid males a The probability that a worker-produced male only inherits maternal or paternal alleles by chance was low (0.016 with six loci and 0.0002 with 12 loci) when assuming equal transmission of maternal and paternal alleles b The probability of not observing at least one recombinant locus over 12 loci for a given individual was always higher than 5 % because recombination can only be observed for heterozygous loci in the mother. However, over few males, not observing a single recombination event could strongly suggest that they originated from a queen matched-mating several ant species (Aron et al 2003;Cournault and Aron 2008;Cournault and Aron 2009). Heads of workers were cut and individually crushed in DAPI solution (CyStain® DNA-1 step, PARTEC©) and then analysed using a PA-I flow cytometer (PARTEC©, Partec68 Gmbh, Münster, Germany).…”

“…In honey bees, workers remove diploid male brood (Woyke 1963;Santomauro et al 2004), but adult diploid males are known to occur in many other social hymenopteran species (reviewed in Darvill et al 2012). In ants, for example, diploid males have been observed in more than 20 species belonging to different subfamilies (Table 1 in Cournault and Aron 2009;Darvill et al 2012). However, triploid females have been reported only rarely (in endangered populations of Bombus florigelus, Takahashi et al 2008; in Polistes dominulus, Liebert et al 2005; in introduced populations of Solenopsis invicta, Krieger et al 1999 and in Tapinoma erraticum, Cournault and Aron 2009).…”

“…In ants, for example, diploid males have been observed in more than 20 species belonging to different subfamilies (Table 1 in Cournault and Aron 2009;Darvill et al 2012). However, triploid females have been reported only rarely (in endangered populations of Bombus florigelus, Takahashi et al 2008; in Polistes dominulus, Liebert et al 2005; in introduced populations of Solenopsis invicta, Krieger et al 1999 and in Tapinoma erraticum, Cournault and Aron 2009). This suggests that diploid males have a low success in fertilizing females or that triploid females are less viable in natural populations.…”