Pair‐living in the Absence of Obligate Biparental Care in a Lizard: Trading‐off Sex and Food?

A pair‐living social organisation can typically be explained by obligate biparental care. We investigated pair‐living in the absence of biparental care in the Australian sleepy lizard, Tiliqua rugosa, which forms exceptionally strong pair bonds. We fitted 10 lizards, five male–female pairs, with Global Positioning System (GPS) recorders and continuously monitored social associations and separations between active pair partners, based on location records taken every 10 min over 3 mo. Males temporarily separated and reunited the pair more frequently than females, but females also contributed to the maintenance of the pair bond. These behavioural data were consistent with the hypothesis that females successfully coerce males into associations with one female. Lower frequencies of social association between pair partners once mating had finished support this interpretation. Males that are coerced into pair associations appear to experience higher costs of pair‐living than females, because males initiated temporary separations of the pair more frequently than females. Males showed higher movement activity and remained active later each day. This sex bias in activity may be an important mechanism to mitigate the higher costs of pair‐living for males. Costs for males might include within‐pair competition for food as females appear more competitive. Our study provides detailed empirical data on a lizard pair bond and provides important insights into pair‐living in the absence of biparental care.     

Trace elements in otoliths of the two‐banded bream from a coastal region in the south‐west Mediterranean: are there differences among locations?

There were no significant differences in otolith chemistry (Li, Mn, Sr, Cd, Ba) of Diplodus vulgaris between sites (distances >100 m) and few differences among locations (distance >10 km) along the south-west coast of Spain. Multivariate analysis of otolith chemistry detected a difference among locations, but a posteriori comparisons could not detect which locations differed. This is one of the few studies to show little variation in otolith chemistry among locations. Of the studies reviewed, <10% showed non-significant differences. It is suggested that the region of the Mediterranean where this study was conducted may be relatively homogeneous in comparison to estuarine and coastal regions where many of the other studies have been conducted.     

Who flies first? – habitat‐specific phenological shifts of butterflies and orthopterans in the light of climate change: a case study from the south‐east Mediterranean

1. Insects undergo phenological change at different rates, showing no consistent trend between habitats, time periods, species or groups. Understanding how and why this variability occurs is crucial. 2. Phenological patterns of butterflies and Orthoptera were analysed using a novel approach of standardised major axis (SMA) analysis. It was investigated whether: (i) phenology (the mean date and duration of flight) of butterflies and Orthoptera changed from one survey (1998 and 1999 respectively) to another (2011), (ii) the rate at which phenology changed differed between taxa and (iii) phenological change was significantly different across habitat types (agriculture fields, grasslands, and forests). Using the 2011 dataset, we investigated relationships between habitat‐specific variables and species phenology. 3. For both groups, late‐emerging species had an advanced onset on the second survey while the duration showed no consistent trend for butterflies and did not change for Orthoptera. Although the rate at which phenology changed was consistent between the two groups, at the habitat level, a longer duration of flight period emerged for butterflies in agriculture fields while Orthoptera showed no differentiation in flight duration between habitats. We found an earlier emergence of butterflies in grasslands compared to forests, attributed to habitat‐specific temperature, whereas spatial variation in humidity had a significantly lower effect on butterflies' phenology in grasslands compared to forests. A gradual delay of butterfly appearances as the canopy cover increased was also found. 4. The utility of SMA analysis was demonstrated in phenological studies and evidence was detected that both habitat type and habitat‐specific variables refine species' phenological responses.