Measures of the developmental stability, body size and body condition in the black-striped mouse (Apodemus agrarius) as indicators of a disturbed environment in northern Serbia

Abstract

In the present study, an additional combination of end-points was used to evaluate the effects of industrial development on the natural population of the black-striped mouse (Apodemus agrarius), previously estimated using cytogenetic and morphometric assays. Developmental stability was assessed by determining the level of fluctuating asymmetry (FA) and the total amount of phenotypic variability (PV). Body weight (BW) and body length (BL) were also used as indices of body size, while the quotient between observed and expected values of body weight presented an index of body condition (BCl). The experimental design employed in this study is unique because only a few studies have been conducted with A. agrarius and because no investigator has previously used this combination of end-points in an environmental quality monitoring study. FA was increased in the polluted area for foramen parietalis, foramen dentale, foramen palatinum and foramen angularis. Males from the polluted site had significantly higher FA for foramen parietalis compared with male mice from the reference area. Juvenile animals from the polluted area had significantly higher FAs for foramen dentale and foramen palatinum compared to adults. However, when all the foramina were considered together, a three-way analysis of variance revealed that there was no significant interaction between the factors (sex x age category x site) on the FA (average value). A comparison of PVs indicated higher values in the polluted area for all analyzed characters. For foramen parietalis and foramen dentale, PVs were significantly greater in the polluted site than in the control area. Within the same sex, PVs were significantly greater in mice from the polluted site compared with mice from the control area. The results also indicated that mice trapped at the contaminated site had a reduced body size and poorer body condition. Adult mice exhibited better body condition than juveniles, as revealed by the significantly higher BCI values. Finally, to investigate the relative importance of the three potential biomarkers, a multivariate analysis of variance (MANOVA procedure) was performed. The MANOVA's results revealed the significant effects of age category, site and interaction for sex x site on FA (average value), size and body condition. In conclusion, the results indicated that despite A. agrarius's high tolerance to contaminants it may be an important species for environmental quality evaluation studies.