Data from: Multiple paternity in the Norway rat, Rattus norvegicus, from urban slums in Salvador, Brazil

The Norway rat, Rattus norvegicus, is one of the most important pest
species globally and the main reservoir of leptospires causing human
leptospirosis in the urban slums of tropical regions. Rodent control is a
frequent strategy in those settings to prevent the disease but rapid
growth from residual populations and immigration limit the long-term
effectiveness of interventions. To characterize the breeding ecology of R.
norvegicus and provide needed information for the level of genetic mixing,
which can help identify inter-connected eradication units, we estimated
the occurrence of multiple paternity, distances between mothers and sires,
and inbreeding in rats from urban slum habitat in Salvador, Brazil. We
genotyped 9 pregnant females, their 66 offspring, and 371 males at 16
microsatellite loci. Multiple paternity was observed in 22% (2/9) of the
study litters. Of the 12 sires that contributed to the 9 litters, we
identified 5 (42%) of those sires among our genotyped males. Related males
were captured in close proximity to pregnant females (the mean
inter-parent trapping distance per litter was 70 m, ±58 m SD). Levels of
relatedness between mother–sire pairs were higher than expected and
significantly higher than relatedness between all females and non-sire
males. Our findings indicate multiple paternity is common, inbreeding is
apparent, and that mother–sire dyads occur in close proximity within the
study area. This information is relevant to improve the spatial definition
of the eradication units that may enhance the effectiveness of rodent
management programs aimed at preventing human leptospirosis. High levels
of inbreeding may also be a sign that eradication efforts are successful.