Asexual queen succession in the higher termite Embiratermes neotenicus

Abstract

Asexual queen succession (AQS), in which workers, soldiers and dispersing reproductives are produced sexually while numerous non-dispersing queens arise through thelytokous parthenogenesis, has recently been described in three species of lower termites of the genus Reticulitermes. Here, we show that AQS is not an oddity restricted to a single genus of lower termites, but a more widespread strategy occurring also in the most advanced termite group, the higher termites (Termitidae). We analysed the genetic structure in 10 colonies of the Neotropical higher termite Embiratermes neotenicus (Syntermitinae) using five newly developed polymorphic microsatellite loci. The colonies contained one primary king accompanied either by a single primary queen or by up to almost 200 neotenic queens. While the workers, the soldiers and most future dispersing reproductives were produced sexually, the non-dispersing neotenic queens originated through thelytokous parthenogenesis of the founding primary queen. Surprisingly, the mode of thelytoky observed in E. neotenicus is most probably automixis with central fusion, contrasting with the automixis with terminal fusion documented in Reticulitermes. The occurrence of AQS based on different mechanisms of ploidy restoration raises the hypothesis of an independent evolutionary origin of this unique reproductive strategy in individual lineages of lower and higher termites.

Keywords: Isoptera; Termitidae; breeding system; reproductive strategies; termites; thelytokous parthenogenesis.

Figure 1.

Photographs of Embiratermes neotenicus reproductives. (a) Primary king (PRIM K) and primary queen (PRIM Q) excavated from a small nest together with soldiers (SOLD) and workers (WORK). (b) Primary king (PRIM K) and numerous nymphoid neotenic queens (NEO Q) excavated from a large nest. (Online version in colour.)