Browsing by Author "Borremans, B."

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Arenavirus infection correlates with lower survival of its natural rodent host in a long-term capture-mark-recapture study
(2018) Mariën, J.; Sluydts, V.; Borremans, B.; Gryseels, S.; Broecke, B. V.; Sabuni, C. A.; Katakweba, A. A. S.; Mulungu, L. S.; Günther, S.; de Bellocq, J. G.; Massawe, A. W.; Leirs, H
Background: Parasite evolution is hypothesized to select for levels of parasite virulence that maximise transmission success. When host population densities fluctuate, low levels of virulence with limited impact on the host are expected, as this should increase the likelihood of surviving periods of low host density. We examined the effects of Morogoro arenavirus on the survival and recapture probability of multimammate mice (Mastomys natalensis) using a seven-year capture-mark-recapture time series. Mastomys natalensis is the natural host of Morogoro virus and is known for its strong seasonal density fluctuations. Results: Antibody presence was negatively correlated with survival probability (effect size: 5–8% per month depending on season) but positively with recapture probability (effect size: 8%). Conclusions: The small negative correlation between host survival probability and antibody presence suggests that either the virus has a negative effect on host condition, or that hosts with lower survival probability are more likely to obtain Morogoro virus infection, for example due to particular behavioural or immunological traits. The latter hypothesis is supported by the positive correlation between antibody status and recapture probability which suggests that risky behaviour might increase the probability of becoming infected.
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.
Evaluation of short-, mid- and long-term effects of toe clipping on a wild rodent
(Wildlife Research, 2015) Leirs, H.; Makundi, Rhodes H.; Sluydts, V.; Borremans, B.
Context. Toe clipping is a widely used method for permanent marking of small mammals, but its effects are not well known, despite the ethical and scientific implications. Most studies do not find any clear effects, but there is some indication that toe clipping can affect survival in specific cases. Although effects on survival are arguably the most important, more subtle effects are also plausible, yet very few studies have included body condition and none has investigated effects on mobility. Aims. We analysed the effects of toe clipping on free-living Mastomys natalensis, a common, morphologically and behaviourally intermediate small rodent. Methods. Using a 17-year capture–mark–recapture dataset, we compared movement, body weight and survival between newly and previously clipped animals, and tested whether any of these parameters correlated with the number of clipped toes. Key results. No evidence for a correlation between total number of clips and any of the variables was found. Newly clipped animals had a slightly smaller weight change and larger travel distance than did those that were already clipped, and we show that this is most likely due to stress caused by being captured, clipped and handled for the first time rather than to the actual clipping. Conclusions. The combination of trapping, handling and marking has a detectable effect on multimammate mice; however, there is no evidence for a clear effect of toe clipping. Implications. Our study suggests a re-evaluation of ethical guidelines on small-mammal experiments, so as to reach a rational, fact-based decision on which marking method to use.
Happily together forever: temporal variation in spatial patterns and complete lack of territoriality in a promiscuous rodent
(2013-08-31) Borremans, B.; Hughes, N. K.; Reijniers, J.; Sluydts, V.; Katakweba, A. A. S.; Mulungu, Loth S.; Sabuni, C. A; Makundi, Rhodes H.; Leirs, H.
The availability of resources, their effect on population density and territoriality, and the ways in which these factors are interwoven with mating systems are important determinants of small mammal space use. It is often difficult to study these patterns in an integrated way, however, especially because long-term data are needed but not readily available. In this paper, we investigate effects of population density, season and breeding status on home range patterns of the promiscuous rodent Mastomys natalensis using monthly capture-mark-recapture data collected over 17 years in a 3-ha grid. Home ranges were estimated using minimum convex polygons bounded by trap locations, and home range overlap and visitation rates were calculated as a measure of territoriality. As higher population densities coincide with increased resource availability, we predicted that home range sizes would correlate negatively with density. Furthermore, as M. natalensis is promiscuous and population densities are generally high, we predicted that territoriality would be low, and home range overlap would therefore be high. Contrary to expectations the home ranges of female adults increased with population density, although those of male adults and subadults followed the expected decrease. Home range overlap and visitation rates were generally high, and increased significantly with population density. More importantly, they were never lower than those of simulated datasets consisting of randomly moved home ranges. These results therefore suggest that M. natalensis displays a complete lack of territoriality that is rarely seen in small mammals but still meets predictions based on knowledge of density and mating system.
Happily together forever: temporal variation in spatial patterns and complete lack of territoriality in a promiscuous rodent
(The Society of Population Ecology and Springer Japan, 2014-01) Borremans, B.; Hughes, N. K.; Reijniers, J.; Sluydts, V.; Katakweba, A. A. S.; Mulungu, Loth S.; Sabuni, C. A.; Makundi, Rhodes H.; Leirs, H.
The availability of resources, their effect on population density and territoriality, and the ways in which these factors are interwoven with mating systems are important determinants of small mammal space use. It is often difﬁcult to study these patterns in an integrated way, however, especially because long-term data are needed but not readily available. In this paper, we investigate effects of population density, season and breeding status on home range patterns of the promiscuous rodent Mastomys natalensis using monthly capture-mark-recapture data collected over 17 years in a 3-ha grid. Home ranges were estimated using minimum convex polygons bounded by trap locations, and home range overlap and visitation rates were calculated as a measure of territoriality. As higher population densities coincide with increased resource availability, we predicted that home range sizes would correlate negatively with density. Furthermore, as M. natalensis is promiscuous and population densities are generally high, we predicted that territoriality would be low, and home range overlap would therefore be high. Contrary to expectations the home ranges of female adults increased with population density, although those of male adults and subadults followed the expected decrease. Home range overlap and visitation rates were generally high, and increased signiﬁcantly with population density. More importantly, they were never lower than those of simulated datasets consisting of randomly moved home ranges. These results therefore suggest that M. natalensis displays a complete lack of territoriality that is rarely seen in small mammals but still meets predictions based on knowledge of density and mating system.
When viruses don’t go viral: the importance of host phylogeographic structure in the spatial spread of arenaviruses
(Public Library of Science, 2017) Gryseels, S.; Baird, S. J. E.; Borremans, B.; Makundi, R.; Leirs, H.; Bellocq, J. G.
Many emerging infections are RNA virus spillovers from animal reservoirs. Reservoir identification is necessary for predicting the geographic extent of infection risk, but rarely are taxonomic levels below the animal species considered as reservoir, and only key circumstances in nature and methodology allow intrinsic virus-host associations to be distinguished from simple geographic (co-)isolation. We sampled and genetically characterized in detail a contact zone of two subtaxa of the rodent Mastomys natalensis in Tanzania. We find two distinct arenaviruses, Gairo and Morogoro virus, each spatially confined to a single M. natalensis subtaxon, only co-occurring at the contact zone’s centre. Inter-subtaxon hybridization at this centre and a continuum of quality habitat for M. natalensis show that both viruses have the ecological opportunity to spread into the other substaxon’s range, but do not, strongly suggesting host-intrinsic barriers. Such barriers could explain why human cases of another M. natalensisborne arenavirus, Lassa virus, are limited to West Africa