Seasonal adaptations in energy budgeting in the primate Lepilemur leucopus

Abstract

The spiny forest of South Madagascar is one of the driest and most unpredictable habitats in Africa. The small-bodied, nocturnal primate Lepilemur leucopus lives in this harsh habitat with high diurnal and seasonal changes in ambient temperature. In this study, we investigated seasonal adaptions in energy budgeting of L. leucopus, which allow it to live under these conditions by measuring resting metabolic rate using open-flow respirometry. No signs of heterothermy were detected, and resting metabolic rate was significantly lower in the warmer wet season than in the colder dry season. In fact, L. leucopus possesses one of the lowest mass-specific metabolic rates measured so far for an endotherm, probably the result of adaptations to its habitat and folivorous and potentially toxic diet. Surprisingly, we identified a shift of the thermoneutral zone from between 25 and 30 °C in the wet season to between 29 and 32 °C in the cool dry season. L. leucopus seems to be more affected by the hot daytime temperatures during the dry season and thermoregulation seems to be more costly during this time, which makes this shift of the thermoneutral zone advantageous. Our findings suggest that L. leucopus has a very small scope to unfavorable conditions, making it highly vulnerable, e.g., to changing conditions due to climate change.

Activity of wild Japanese macaques in Yakushima revealed by camera trapping: Patterns with respect to season, daily period and rainfall

“…Our prediction on seasonality was supported; we found that temperature positively affected the activity of Japanese macaques during the studied year, indicating that macaques were more active when the thermal conditions were favorable. The thermoneutral zone, i.e., the ambient temperature range that does not require animals to allocate additional energetic costs to thermoregulation, is reported to be 5–28°C for colobus monkeys [ 49 ], 20–27°C for titis [ 50 ], 25–30 for tarsiers [ 51 ], 25–32°C for sportive lemurs [ 52 ], above 27°C for mouse lemurs [ 53 ], 27–34°C for pygmy marmosets [ 54 ] and 17–28°C for chimpanzees [ 55 ]. Even though the thermoneutral zone for macaques has not been reported, a feeding experiment on captive macaques indicated that they changed food intake and food selection when room temperature decreased from 29 to 15°C [ 56 ].…”

Post-metamorphic carry-over effects of altered thyroid hormone level and developmental temperature: physiological plasticity and body condition at two life stages in Rana temporaria

“…Values for SMR and mass were log-transformed, because metabolism is a power function of mass(Orlofske and Hopkins 2009;Orlofske et al 2017). Only the lowest 30% of the values were used to ensure that only data of resting individuals were included in analyses, thereby omitting any phases of stress, disturbance, or activity(Orlofske and Hopkins 2009;Peck and Moyano 2016;Orlofske et al 2017;Bethge et al 2017).…”

The Influence of Seasonal Availability of Young Leaves on Dietary Niche Separation in Two Ecologically Similar Folivorous Lemurs

“…It is unclear why, however, L. fleuretae did not show a timeminimising strategy as other Lepilemur spp. (e.g., L. leucopus [Bethge et al, 2017]; L. sahamalaza [Mandl et al, 2018]). This genus has received relatively little attention in moist forests, so we cannot exclude that the pattern we observed is not uncommon in this habitat.…”