Breeding systems and reproductive strategies in Italian Reticulitermes colonies (Isoptera: Rhinotermitidae)

Abstract

Biological traits and colony structure are difficult to analyze in subterranean termites owing to their cryptic lifestyle and their often elusive breeding system. However, the use of molecular markers in a population genetics framework allows the investigation of such aspects. We present here the colony genetic structures of 12 samples collected along the Italian peninsula of two Reticulitermes species (the native R. lucifugus and the introduced R. urbis) analyzed through nuclear microsatellite markers. Reproductive strategies and colony breeding systems differ between the two species. Secondary reproductives of R. lucifugus, collected in three colonies, are all females; genotyping comparisons between these females and their nest mate workers clearly indicate the presence of asexual queen succession (AQS) events in this species, as observed in the Japanese R. speratus and in the North-American R. virginicus. Two other R. lucifugus colonies have a mixed family genetic pattern, possibly as the result of colony fusion events: accordingly, relatedness estimates indicate the presence of genetically unrelated workers. On the contrary, all R. urbis colonies have a genetic structure compatible with the presence of multiple secondary reproductives, as expected on the basis of previous analyses. Moreover, neotenics’ sex ratio is balanced and their heterozygosity is comparable to that of nest mate workers, suggesting that AQS is lacking in this taxon. The differences observed in such biological traits between the two species are discussed in the light of their invasive potential.