Body Temperature Patterns and Rhythmicity in Free-Ranging Subterranean Damaraland Mole-Rats, Fukomys damarensis

Body temperature (Tb) is an important physiological component that affects endotherms from the cellular to whole organism level, but measurements of Tb in the field have been noticeably skewed towards heterothermic species and seasonal comparisons are largely lacking. Thus, we investigated patterns of Tb patterns in a homeothermic, free-ranging small mammal, the Damaraland mole-rat (Fukomys damarensis) during both the summer and winter. Variation in Tb was significantly greater during winter than summer, and greater among males than females. Interestingly, body mass had only a small effect on variation in Tb and there was no consistent pattern relating ambient temperature to variation in Tb. Generally speaking, it appears that variation in Tb patterns varies between seasons in much the same way as in heterothermic species, just to a lesser degree. Both cosinor analysis and Fast Fourier Transform analysis revealed substantial individual variation in Tb rhythms, even within a single colony. Some individuals had no Tb rhythms, while others appeared to exhibit multiple rhythms. These data corroborate previous laboratory work showing multiplicity of rhythms in mole-rats and suggest the variation seen in the laboratory is a true indicator of the variation seen in the wild

Plasticity in Diurnal Activity and Temporal Phenotype During Parental Care in European Starlings, Sturnus Vulgaris

We used an automated radiotelemetry system to determine diurnal patterns of activity and temporal phenotype (onset and cessation of activity) in female European starlings during breeding. Parental care is thought to be the most ‘costly’ part of reproduction, with high rates of intense activity due to foraging and provisioning for chicks, so we predicted that variation in timing of activity should be closely related to breeding success. Diurnal variation in activity varied systematically with breeding stage in a way consistent with specific demands of each phase of parental care: incubating females were more active late in the day (1600–1800 hours), while chick-rearing females were more active early in the morning (0700–1100 hours). There was marked individual variation in timing of onset, and to a lesser extent cessation, of activity, e.g. chick-rearing females first became active 7–127 min after morning civil twilight, with low to moderate repeatability within and among breeding stages (individual explained 2–62% of total variation). On average, females were active later, and ceased being active earlier, during chick rearing compared with incubation. Chick-rearing birds had a longer active day, but only by 2.3% (36% of the seasonal increase in total available daylength). Thus, chick-rearing females were relatively less active (‘lazier’), which is consistent with the idea that parents work more efficiently rather than simply working harder. We found little evidence that chick-rearing activity was associated with variation in measures of current reproduction (provisioning rate, number and quality of chicks), future fecundity (initiating a second brood, cumulative 2-year productivity) or survival (local return rate). Our study demonstrates that time-keeping mechanisms show plasticity in response to reproductive state and can be modulated by ‘biotic’ (e.g. prey availability) or ‘social’ time (demands of parental care)

The effect of characteristics of proteins fed during gestation and lactation on development of metabolic syndrome in dams and male offspring of Wistar rats

Objective The objective of the study is to examine the role of characteristics of proteins in maternal and weaning diets on risk of metabolic syndrome in male offspring. Methods Pregnant Wistar rats were allocated to two groups (n = 12) and were fed the AIN‐93G diets based on either intact protein‐based diet (IPD) or mixed amino acid‐based diet (AAD) from day 3 of gestation throughout gestation and lactation. Male offspring were weaned to either an IPD or AAD diet for 18 weeks. Results In dams, AAD group had lower body weight in post‐partum period and higher pulse rate compared with IPD group. In pups born to AAD dams, birth weight and body weight were significantly lower, and systolic blood pressure and fasting blood glucose were significantly higher compared with those born to IPD dams. Fat/weight ratio, insulin and homeostasis model assessment of insulin resistance were not influenced by either maternal or weaning diet. Conclusions These results indicate that the physico‐chemical structure of proteins fed to dams is important in altering risk factors of metabolic syndrome in the offspring, while weaning diets do not seem to play a role. IPD had more favourable effect than AAD. These results may also indicate that dietary recommendations during development must be updated based on physiological properties of dietary proteins that are beyond their nutritional role