Molecular-genetic analyses of dispersal and breeding behaviour in the Australian termite Coptotermes lacteus: evidence for non-random mating in a swarm-dispersal mating system

Thompson, Graham J., Lenz, Michael, Crozier, Ross H., and Crespi, Bernard J. (2007) Molecular-genetic analyses of dispersal and breeding behaviour in the Australian termite Coptotermes lacteus: evidence for non-random mating in a swarm-dispersal mating system. Australian Journal of Zoology, 55 (4). pp. 219-227.

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Abstract

We used microsatellite DNA markers to infer the dispersal and breeding behaviour of Coptotermes lacteus, a termite whose large mounds are a conspicuous feature of Australia's central east coast. We genotyped a subsample of neuter offspring for each of 38 colonies sampled over two spatially separated populations, one in a natural forest and the other in an exotic radiata pine plantation. All colonies showed offspring genotype frequencies consistent with a single reproductive pair. This result confirms that stable monogamy is the normal breeding arrangement for this species and that multi-reproductive colonies are rare. The two study populations were significantly differentiated and the distance separating them (~150 km) is therefore an effective constraint on gene flow. The populations themselves, however, were not noticeably subdivided above the level of colony. This lack of within-population viscosity is unexpected for weakly dispersing species and suggests that local gamete dispersal is in fact quite effective in C. lacteus. Nonetheless, dispersing sexuals do not appear to mate randomly. Instead, all four microsatellite loci are deficient in heterozygotes, indicating that populations are substantially inbred, irrespective of habitat. Evidence from hierarchical F-statistics, spatial genetic autocorrelation and relatedness calculations suggests that deviations from Hardy–Weinberg equilibrium may result from either a preference for non-sibling relatives over totally unrelated mates, or from random mating with viscosity - though evidence for the latter hypothesis was not detected. These findings suggest that swarm-dispersal mating systems, usually considered to produce outbreeding and panmixia, can instead involve a notable degree of non-random mating.

Item ID: 2377
Item Type: Article (Research - C1)
ISSN: 1446-5698
Keywords: Isoptera; microsatellites; population genetics; social insects
Additional Information:

Date Deposited: 20 Jul 2009 05:14
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 50%
06 BIOLOGICAL SCIENCES > 0699 Other Biological Sciences > 069999 Biological Sciences not elsewhere classified @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 80%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960806 Forest and Woodlands Flora, Fauna and Biodiversity @ 20%
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