Extreme genetic mixing within colonies of the wood‐dwelling termiteKalotermes flavicollis(Isoptera,Kalotermitidae)

Abstract

The existence of altruism in social insects is commonly attributed to altruistic individuals gaining indirect fitness through kin selection. However, recent studies suggest that such individuals might also gain direct fitness through reproduction. Experimental studies on primitive wood-dwelling termites revealed that colony fusion often causes the death of primary reproductives (queen and king), allowing opportunities for workers to inherit the nest by developing into replacement reproductives (neotenics). Therefore, colony fusion has been proposed as an important factor that may have favoured sociality in termites. However, whether colony fusion occurs frequently in natural populations of wood-dwelling termites remains an open question. We analysed eleven colonies of the wood-dwelling termite Kalotermes flavicollis (Kalotermitidae), using two mitochondrial and five nuclear microsatellite markers. Nine of eleven colonies (82%) were mixed families, with offspring of three or more primary reproductives. To our knowledge, this result represents the highest frequency of mixed-family colonies ever reported in termites. Moreover, genetic mixing of colonies appeared extreme in two ways. First, the number of haplotypes per colony was exceptionally high (up to nine), indicating that colonies were composed of multiple queens' offspring. Second, some mixed-family colonies included individuals belonging to two highly divergent genetic lineages. F-statistics and relatedness values suggest that mixed-family colonies most likely result from colony fusion, giving support to the accelerated nest inheritance theory. These findings raise important questions about the mode of foundation of mixed-family colonies and the evolutionary forces that maintain them within populations.

Communication and Social Regulation in Termites

“…It has been suggested that the occurrence of fertile soldiers in Termopsidae is an adaptation of the future potential replacement reproductives for such conflicts . Colony fusions that result from conflicts and the elimination of primary reproductives also occur in other one-piece-type termites, such as C. secundus (Korb and Schneider 2007;Korb and Roux 2012) and K. flavicollis (Luchetti et al 2013a). In contrast, the rare cases of cooperative colony founding are largely restricted to the higher termites (Hacker et al 2005;Hartke and Rosengaus 2013).…”

First record of intersex in neotenic reproductives of the termite Cryptotermes brevis (Isoptera: Kalotermitidae)

“…flavicollis , Luchetti et al . () found high genetic diversity, indicating that families are mixed and composed of descendants of multiple neotenic queens in this species. These findings give rise to important questions regarding how these mixed families are formed, and how the reproductive potential varies among these reproductives.…”

“…Another development path for pseudergates is to molt and produce neotenic reproductives, which will remain in the nest and inbreed (Luchetti et al . ). The production of neotenic reproductives has already been studied for C .…”

“…Experiments with termites of this family revealed that the fusion of neighboring colonies leads to the death of the primary reproductives (king and queen), allowing the pseudergates the opportunity to inherit the nest as replacement reproductives (Korb ; Luchetti et al . ). In colonies of K .…”

Social Recognition in Invertebrates

“…It has been suggested that the occurrence of fertile soldiers in Termopsidae is an adaptation of the future potential replacement reproductives for such conflicts . Colony fusions that result from conflicts and the elimination of primary reproductives also occur in other one-piece-type termites, such as C. secundus (Korb and Schneider 2007;Korb and Roux 2012) and K. flavicollis (Luchetti et al 2013a). In contrast, the rare cases of cooperative colony founding are largely restricted to the higher termites (Hacker et al 2005;Hartke and Rosengaus 2013).…”