Wingless and intermorphic males in the ant Cardiocondyla venustula

Abstract

The ant genus Cardiocondyla is characterized by a pronounced male diphenism with wingless fighter males and winged disperser males. Winged males have been lost convergently in at least two species-rich clades. Here, we describe the morphological variability of males of C. venustula from uThukela valley, South Africa. Winged males appear to be absent from this species. However, in addition to wingless ("ergatoid") males with widely fused thoracic sutures and without ocelli, "intermorphic" males exist that combine the typical morphology of wingless males with characteristics of winged males, e.g., more pronounced thoracic sutures, rudimentary ocelli, and vestigial wings. Similar "intermorphic" males have previously been described from one of several genetically distinct lineages of the Southeast Asian "C. kagutsuchi" complex .To determine whether male morphology is associated with distinct clades also in C. venustula, we sequenced a 631 bp fragment of mitochondrial DNA of workers from 13 colonies. We found six haplotypes with a sequence variation of up to 5.7%. Intermorphic and wingless males did not appear to be associated with a particular of these lineages and within colonies showed the same sequence.Interestingly, two colonies contained workers with different haplotypes, suggesting the occasional migration of queens and / or workers between colonies.Keywords Cardiocondyla venustula · male diphenism · ergatoid male · intracolony mtDNA variation 3

Interruption points in the wing gene regulatory network underlying wing polyphenism evolved independently in male and female morphs in Cardiocondyla ants

“…The phylogeny of Cardiocondyla suggests that wingless males originated once at the base of the genus (Oettler, Suefuji, & Heinze, 2010)~20 million years ago (Ward, Brady, Fisher, & Schultz, 2014) and that the winged morph was lost several times independently. This is consistent with the highly variable nature of male phenotypic plasticity within the genus-several species produce wingless males exclusively, while others produce both morphs, and some species even consistently producing intermorphs between winged and wingless males (Cremer, Lautenschläger, & Heinze, 2002;Heinze, Aumeier, Bodenstein, Crewe, & Schrempf, 2012;Yamauchi, Asano, Lautenschläger, Trindl, & Heinze, 2005). This suggests that at the base of the genus, wing polyphenism in males evolved through the environmental induction of phenotypic variation; plastic-winged males may have produced a range of short-winged or wingless phenotypes that were eventually genetically accommodated leading to the evolution of a new developmental switch that gave rise to male wing polyphenism.…”

Between fighting and tolerance: reproductive biology of wingless males in the ant Cardiocondyla venustula

“…Upon collection, colonies contained of up to 100 workers, 1-10 dealate queens (queens that had shed their wings), up to 10 winged female sexuals, and up to 4 males. All males had the typical habitus of ergatoid males, even though some males from Hlalanathi, South Africa had more pronounced thoracic sutures and vestigial wings (e.g., Heinze et al, 2013).…”

Polygyny, Inbreeding, and Wingless Males in the Malagasy Ant Cardiocondyla shuckardi Forel (Hymenoptera, Formicidae)

“…First, its colonies are at least temporarily facultatively polygynous, and second, males are wingless and resemble those of the related species C. venustula in size and morphology (Frohschammer and Heinze 2009). In the studied specimens of C. shuckardi, pronotal shoulders appeared to be less angular than in the presently available males of C. venustula, but because of the limited sample, the large variation of C. venustula males (Heinze et al, 2013) and the lack of males from other species of the C. shuckardi group, it would be premature to define universal diagnostic features. Injuries in the examined males of C. shuckardi and the simultaneous presence of two males in field colonies suggest that males may attack and damage young rivals but do not always engage in lethal fighting with other adult males.…”

“…Heinze and Susanne Jacobs, unpubl. ), and in a native population in South Africa (Heinze et al, 2013). As yet, only wingless males have been found, with some particularly large males from South Africa combining the typical morphology of wingless males with the presence of ocelli and vestigial wings without otherwise approaching the morphology of typical winged ant males.…”