Browsing by Author "Leirsa, H."

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Does exploratory behavior or activity in a wild mouse explain susceptibility to virus infection?
(Current Zoology, 2017) Broecke, B. V.; Borremans, B.; Mariën, J.; Makundi, R. H .; Massawe, A. W.; Hughes, N. K.; Leirsa, H.
Exploration and activity are often described as trade-offs between the fitness benefits of gathering information and resources, and the potential costs of increasing exposure to predators and parasites. More exploratory individuals are predicted to have higher rates of parasitism, but this relationship has rarely been examined for virus infections in wild populations. Here, we used the multimammate mouse Mastomys natalensis to investigate the relationship between exploration, activity, and infection with Morogoro virus (MORV). We characterized individual exploratory behavior (open field and novel object tests) and activity (trap diversity), and quantified the relationship between these traits and infection status using linear regression. We found that M. natalensis expresses consistent individual differences, or personality types, in exploratory behavior (repeatability of 0.30, 95% CI: 0.21–0.36). In addition, we found a significant contrasting effect of age on exploration and activity where juveniles display higher exploration levels than adults, but lower field-activity. There was however no statistical evidence for a behavioral syndrome between these 2 traits. Contrary to our expectations, we found no correlation between MORV infection status and exploratory behavior or activity, which suggests that these behaviors may not increase exposure probability to MORV infection. This would further imply that variation in viral infection between individuals is not affected by between-individual variation in exploration and activity.
Polymorphism in vkorc1 gene of natal multimammate Mice, Mastomys natalensis, in Tanzania
(Journal of Heredity, 2015) Gryseels, S.; Leirsa, H.; Makundi, R.; De Bellocq, J. G.
Resistance of rodents to anticoagulant rodenticides has emerged in several areas across the world. Single nucleotide mutations in the vkorc1 gene have been shown to elicit various levels of anticoagulant resistance, and these mutations are prevalent in several Rattus and Mus musculus populations. In sub-Saharan Africa, the Natal multimammate mouse, Mastomys natalensis, is one of the most damaging pests to crops, and anticoagulant poisons such as bromadiolone are frequently used to control these rodents in agricultural fields. Here, we investigate if vkorc1 shows any polymorphism in natural populations of M. natalensis. We sequenced the third exon of vkorc1 of 162 M. natalensis captured from 14 different agricultural sites in Morogoro Region, Tanzania. In addition to 6 SNPs in the noncoding flanking region, we detected 3 nonsynonymous SNPs in this exon: 10 animals (6.2%) carried a Leu108Val variant, 2 animals (1.2%) an Ala140Thr variant, and 1 animal (0.6 %) an Arg100His variant, all 3 in heterozygous form. Ala140Thr is just one residue from a mutation known to be involved in anticoagulant resistance in Rattus and Mus. While in vitro or in vivo experiments are needed to link vkorc1 genetic polymorphisms to level of VKOR activity and anticoagulant susceptibility, our results suggest that M. natalensis individuals may vary in their response to anticoagulant rodenticides. This is the first vkorc1 sequence data from a species outside the Rattus or Mus genera, and for the first time from a rodent species endemic to Africa.