High occurrence of colony fusion in a European population of the American termite Reticulitermes flavipes

Abstract

International audienceThe coexistence of multiple unrelated reproductives within social insect colonies decreases the relatedness among colony members and therefore challenges kin selection theory. This study investigated the colony genetic structure of a French introduced population of the American subterranean termite Reticulitermes flavipes by analyzing genotypes at eight microsatellite loci and at one mtDNA region. Results revealed that all colonies contained numerous related secondary reproductives, and that 31% of colonies possessed more than two unrelated reproductives. The presence of several unrelated reproductives within colonies of this species is commonly assumed to result from colony fusion. Although such a high occurrence of colony fusion is the highest ever observed in a termite population, it is probable that the available methodology underestimated the detection of colony fusion in French populations. Overall, these results suggest that French colonies might differ strongly from the great majority of American colonies in their capacity to produce secondary reproductives as well as in their ability to merge. The nature and evolutionary origin of these population differences are discussed

Genetic diversity and colony breeding structure in native and introduced ranges of the Formosan subterranean termite, Coptotermes formosanus

“…Outside of Hawaii, only 1 of 13 extended family colonies in South Carolina showed positive F IC values, while none of the 47 extended family colonies from three native populations from China (this study and Husseneder et al 2008) and none of the over 43 extended families from the introduced range of Louisiana Aluko and Husseneder 2007), North Carolina and Japan Perdereau et al 2010b), relatedness among workers is expected to drop below 0.5 (Thorne et al 1999;Bulmer et al 2001), and worker genotypes would not be consistent with being the offspring of neotenics whose origin can be traced back to a single founder pair. However, all Hawaiian colonies with positive F IC showed high relatedness (0.52-0.72), and none had more than four alleles per locus.…”

“…Furthermore, colony fusion, resulting in colonies headed by multiple unrelated reproductives, occurs in a greater rate in introduced populations of R. flavipes (up to 31%, (Perdereau et al 2010b) than in the native range (DeHeer and Vargo 2004), and, in general, populations with high proportions of extended family colonies have the highest rate of colony fusion (Bulmer et al 2001;DeHeer and Kamble 2008). Fusion is facilitated by low levels of aggression among R. flavipes colonies.…”

“…Fusion is facilitated by low levels of aggression among R. flavipes colonies. Incidental aggression has been reported in native North American populations (Shelton and Grace 1996), but aggression is largely lacking in the introduced range (Canada, France) where the highest rate of fusion occurs (Grace 1996;Perdereau et al 2010b).…”

Colony Genetic Structure of Reticulitermes flavipes (Kollar) from Natural Populations in Nebraska

“…It is expected to be negative in simple families headed by a pair of reproductives (Thorne et al 1999, Bulmer et al 2001, Copren 2007, Vargo and Carlson 2006, Vargo et al 2006a, b, Parman and Vargo 2008. For simple families, F /C is expected to be strongly negative, F /C values should approach zero with increasing number of reproductive within colonies and to become positive if there is assertive mating among multiple reproductive within colonies or there is mixing of individuals from different colonies (Crozier and Pamilo 1996, Thorne et al 1999, DeHeer et al 2005, DeHeer and Vargo 2008, Perdereau et al 2010.…”

“…Multiple reproductives can develop within a colony by secondary reproduction, resulting in extended-family colony Barrett 1982, Myles 1999). Furthermore, colonies headed by unrelated reproductives can fuse and develop a mixed colony (Clement 1981, Jenkins et al 1999, Bulmer et al 2001, Matsuura and Nishida 2001, DeHeer and Vargo, 2004, 2008, DeHeer and Kamble 2008, Perdereau et al 2010. DeHeer and Vargo (2004) provided the first evidence that 2 independent colonies of Reticulitermes spp.…”