Genetic Differentiation among Natural Populations of Lepilemur ruficaudatus

We studied the genetic differentiation of five populations of red-tailed sportive lemur Lepilemur ruficaudatus by means of allozyme variability and RAPD polymorphisms in order to test whether the Tsiribihina River separates the distribution areas of Lepilemur ruficaudatus and and L. edwardsi. Genetic data as well as the karyotype of a male individual clearly indicate that the Andramasay Forest in the north of Tsiribihina River is inhabited by Lepilemur ruficaudatus and not by L. edwardsi. We propose that the distribution of the two species are separated by the Manambolo River. However, the northernmost population of Lepilemur ruficaudatus inhabiting the Andramasay Forest is gentically differentiated from those that inhabit the dry forest in the south of Tsiribihina River.     

Locomotor flexibility in Lepilemur explained by habitat and biomechanics

There are at present few comparable studies of lemur locomotion in the wild. This has unfortunately meant we have little knowledge about locomotor variation, and hence flexibility, with regard to differences in support availability and habitat structure. Here we compare the locomotion of Lepilemur edwardsi at Ankarafantsika with that of Lepilemur ruficaudatus at Kirindy‐Mitea National Park. While data were collected by two individuals, at different times, both studies used the same data collection protocol and are hence highly comparable. Locomotor mode, support diameter and orientation, heights, and distances traveled were all collected. We find that locomotor specialization, in this case for vertical leaping, has ensured that some support requirements are independent of habitat. For example, both species used vertical supports most often. However, overall support diameter does indicate a certain degree of flexibility, whereby L. ruficaudatus most often used supports ≤5 cm in diameter and L. edwardsi >5 cm in diameter. Am J Phys Anthropol 156:58–66, 2015 © 2014 Wiley Periodicals, Inc.     

Determinants of Pair‐Living in Red‐Tailed Sportive Lemurs (Lepilemur ruficaudatus)

Pair‐living and a monogamous mating strategy are rare and theoretically unexpected among mammals. Nevertheless, about 10% of primate species exhibit such a social system, which is difficult to explain in the absence of paternal care. In this study, we investigated the two major hypotheses proposed to explain the evolution of monogamy in mammals, the female defence hypothesis (FDH) and the resource defence hypothesis (RDH), in red‐tailed sportive lemurs (Lepilemur ruficaudatus), a nocturnal primate from Madagascar. We analysed behavioural data from eight male–female pairs collected during a 24‐mo field study to illuminate the determinants of pair‐living in this species. Male and female L. ruficaudatus were found to live in dispersed pairs, which are characterised by low cohesion and low encounter rates within a common home range. Social interactions between pair partners were mainly agonistic and characterised by a complete absence of affiliative interactions – body contact was only observed during mating. During the short annual mating season, males exhibited elevated levels of aggression towards mates, as well as extensive mate guarding and increased locomotor activity. In addition, males were exclusively responsible for the maintenance of proximity between pair partners during this period, and they defended their territories against neighbouring males but not against females. Together, these results point towards the importance of female defence in explaining pair‐living in L. ruficaudatus. We discuss the spatial and temporal distribution of receptive females in relation to the female defence strategies of males and suggest possible costs that prevent male red‐tailed sportive lemurs from defending more than one female.     

SmTRC1, a novel Schistosoma mansoni DNA transposon, discloses new families of animal and fungi transposons belonging to the CACTA superfamily

Background

The number of species within the Malagasy genus Lepilemur and their phylogenetic relationships is disputed and controversial. In order to establish their evolutionary relationships, a comparative cytogenetic and molecular study was performed. We sequenced the complete mitochondrial cytochrome b gene (1140 bp) from 68 individuals representing all eight sportive lemur species and most major populations, and compared the results with those obtained from cytogenetic studies derived from 99 specimens.

Results

Interspecific genetic variation, diagnostic characters and significantly supported phylogenetic relationships were obtained from the mitochondrial sequence data and are in agreement with cytogenetic information. The results confirm the distinctiveness of Lepilemur ankaranensis, L. dorsalis, L. edwardsi, L. leucopus, L. microdon, L. mustelinus, L. ruficaudatus and L. septentrionalis on species level. Additionally, within L. ruficaudatus large genetic differences were observed among different geographic populations. L. dorsalis from Sahamalaza Peninsula and from the Ambanja/Nosy Be region are paraphyletic, with the latter forming a sister group to L. ankaranensis.

Conclusion

Our results support the classification of the eight major sportive lemur taxa as independent species. Moreover, our data indicate further cryptic speciation events within L. ruficaudatus and L. dorsalis. Based on molecular data we propose to recognize the sportive lemur populations from north of the Tsiribihina River, south of the Betsiboka River, and from the Sahamalaza Peninsula, as distinct species.     

A possible role of plantations for primate conservation in Madagascar

The utilization of eucalyptus plantations by seven sympatric species of prosimians was studied in the eastern rainforest of Madagascar. The species were Avahi laniger, Cheirogaleus major, Hapalemur griseus, Indri indri, Lemur fulvus, Lepilemur mustelinus, and Microcebus rufus. None of the lemurs was ever found in young eucalyptus plantations with little undergrowth. This was mainly due to the lack of travel opportunities within the shrub layer and between the shrubs and the canopy. Food (mainly berries) is seasonally available in the shrub layer but cannot be exploited because frugivorous lemurs cannot reach it. Old eucalyptus plantations with dense undergrowth are used by all prosimian species. They provide food as well as travel and resting facilities. Mixed tree plantations in the western part of Madagascar were used by groups of Lemur fulvus, Lepilemur mustelinus, and Propithecus verreauxi. According to these results, old eucalyptus plantations and mixed tree species plantations could be used to provide firewood and construction wood for the human population. They also might extend the habitat for lemurs and serve as buffers against human disturbance.     

The metabolism of social subterranean rodents: adaptation to aridity

Summary The social Damara mole-rat Cryptomys damarensis (124 g), has a mean (±SD) resting metabolic rate of 0.57±0.09 cm³ O₂ g^-1 h^-1, within a thermoneutral zone of 27–31° C. This rate of metabolism is 43% lower than that predicted by the curve for rodents, and 29% lower than that predicted by the subterranean rodent curve. These data support the hypothesis that the resting metabolic rates of social and solitary subterranean rodents are lower than those of solitary species inhabiting mesic habitats. These low resting metabolic rates may represent an energy-saving adaptation to aridity. The energetic cost of burrowing, in relation to the dispersion patterns of food in arid habitats, may explain these low metabolic rates.     

Social Organization of Lepilemur ruficaudatus

We characterize the spatial organization of red-tailed sportive lemurs (Lepilemur ruficaudatus) as a key aspect of their social organization and social system. Sportive lemurs are small (<1000 g), nocturnal and folivorous primates endemic to Madagascar. We studied a population of 57 individually-marked individuals in Kirindy Forest, western Madagascar, between 1995 and 2001. We radio-tracked 20 males and 26 females of the marked population to obtain detailed information on the size and location of their home ranges. Census data and morphometric measurements provided complementary data sets. Males and females occupied small (<1 ha) home-ranges. Long-term records from 9 individuals revealed home-range stability over several years. In 4 cases home ranges overlapped extensively with that of one member of the opposite sex; in 2 cases, a spatial association of 1 male and 2 females occurred. However, home ranges overlapped very little with neighboring individuals of both sexes. During the study period, spatially associated individuals used on average 5.6 sleeping trees within 117 days, but they spent on average only about every fourth night together. The data suggest that home ranges in red-tailed sportive lemurs are exclusively used by pairs or trios and that the modal social organization of red-tailed sportive lemurs is pair-living.     

Gene or Size: Metabolic Rate and Body Temperature in Obese Growth Hormone‐Deficient Dwarf Mice

Objective: SMA1 mice carry a missense mutation in the growth hormone gene that leads to semidominant dwarfism and obesity. In this study, the basic thermal and metabolic properties of SMA1 mice were examined to detect metabolic alterations that can support the accretion of excess fat. Research Methods and Procedures: Basal and resting metabolic rates (RMRs) in wild‐type and SMA1 (sma1/+ and sma1/sma1) mice were determined by indirect calorimetry. Body temperature (T_b) was recorded using intraperitoneally implanted temperature‐sensitive transmitters, and body composition was determined by DXA. Results: SMA1 mice have proportionally lower basal and resting metabolic rates, higher body mass (BM)‐specific RMRs, and a higher lower critical temperature, and display a decrease in T_b by 0.4 °C in sma1/+ and 0.9 °C in sma1/sma1. Discussion: The analysis of gene effects on BM and energy expenditure in mouse mutants must consider the appropriate allometric relationship between BM and metabolic rate. With the exception of T_b, all metabolic alterations observed in SMA1 reflect reduced size.     

Diving metabolism and thermoregulation in common and thick-billed murres

The diving and thermoregulatory metabolic rates of two species of diving seabrid, common (Uria aalge) and thick-billed murres (U. lomvia), were studied in the laboratory. Post-absorptive resting metabolic rates were similar in both species, averaging 7.8 W·kg^-1, and were not different in air or water (15–20°C). These values were 1.5–2 times higher than values predicted from published allometric equations. Feeding led to increases of 36 and 49%, diving caused increases of 82 and 140%, and preening led to increases of 107 and 196% above measured resting metabolic rates in common and thick-billed murres, respectively. Metabolic rates of both species increased linearly with decreasing water temperature; lower critical temperature was 15°C in common murres and 16°C in thick-billed murres. Conductance (assuming a constant body temperature) did not change with decreasing temperature, and was calculated at 3.59 W·m^-2·^oC^-1 and 4.68 W·m^-2·^oC^-1 in common and thick-billed murres, respectively. Murres spend a considerable amount of time in cold water which poses a significant thermal challenge to these relatively small seabirds. If thermal conductance does not change with decreasing water temperature, murres most likely rely upon increasing metabolism to maintain body temperature. The birds probably employ activities such as preening, diving, or food-induced thermogenesis to meet this challenge.Abbreviations ADL aerobic dive limit - BMR basal metabolic rate - FIT food-induced thermogenesis - MHP metabolic heat production - MR metabolic rate - PARR post-absorption resting rate - RMR resting metabolic rate - RQ respiratory quotient - SA surface area - STPD standard temperature and pressure (25°C, 1 ATM) - T _a ambient temperature - T _b body temperature - T _IC Iower critical temperatiure - TC thermal conductance - V oxygen consumption rate - W body mass     

Infanticide by a Male Milne-Edwards' Sportive Lemur (Lepilemur edwardsi) in Ampijoroa,NW-Madagascar

During a long-term field study on the behavioral ecology and communication of a population of the monogamous Milne-Edwards' sportive lemur (Lepilemur edwardsi) in NW-Madagascar, we recorded for the first time an infanticide in a nocturnal lemur. A male newcomer killed the infant of a female whose male partner had left her recently. Both the social-pathology and the sexual-selection hypotheses may explain infanticidal behavior in Lepilemur edwardsi.     

The metabolic rates associated with resting, and with the performance of agonistic, submissive and digging behaviours in the cichlid fish Neolamprologus pulcher (Pisces: Cichlidae)

We measured the metabolic rates as a direct estimate of energy expenditure of individual Neolamprologus pulcher, a cooperatively breeding cichlid fish, when resting and when performing agonistic, submissive or digging behaviours in a respirometer. Standard and routine metabolic rates increased linearly with body mass (range 0.9–8.4 g) when plotted on a doubly logarithmic scale (linear regression equations: standard metabolic rate: log individual oxygen consumption rate = 0.65 + 0.86 log body mass; routine metabolic rate: log individual oxygen consumption rate = 0.75 + 0.86 log body mass). Routine metabolic rates were, on average, 30% higher than standard metabolic rates. Submissive and agonistic behaviours raised routine metabolic rates by factors of 3.3 and 3.9, respectively. Digging resulted in a 6.1-fold increase of routine metabolic rates. Differences in metabolic rates between active and resting rates were statistically significant. However, those between the three behaviours were not. Mean opercular beat frequencies correlated significantly with routine metabolic rates and with metabolic rates when performing specific behaviours, which offers methodological prospects for field measurements. In N. pulcher, the high energy expenditure for submissive behaviour may indicate that this is a reliable signal. The considerable energy expenditure involved in territory defence suggests that these costs should be considered in addition to risk in cost-benefit analyses. This is the first study in which the energy expenditures of specific social and territory maintenance behaviours of individual fish were measured directly by respirometry and within the usual social setting of the fish. Accepted: 20 February 1998     

Seasonal variation in the resting metabolic rate of male wood mice Apodemus sylvaticus from two contrasting habitats 15 km apart

Diurnal and nocturnal resting metabolic rates of winter- and summer-acclimatized adult male wood mice Apodemus sylvaticus from two adjacent populations, 15 km apart, were measured. One population lived in deciduous woodland, and experienced a narrower daily range of temperatures than the second population, which inhabited maritime sand-dunes. Ambient temperature and body mass had significant effects on the resting metabolism of mice, excluding winter-acclimatized sand-dune animals where only temperature explained significant amounts of the observed variation. Only in this latter group could a thermoneutral zone be determined, with a lower critical temperature of ca. 25 °C and resting metabolism of 0.155 W. Nocturnal resting metabolic rates were significantly greater than diurnal levels. Winter acclimatization was associated with reductions in thermal conductance and resting metabolism, thus minimizing energy expenditure at rest. Site differences in thermoregulatory strategies were only found in winter, thermal conductances remained similar but mice from the sand-dunes had significantly lower metabolic rates than those from the woodland. Winter acclimatization in wood mice was influenced by factors in addition to photoperiod. Intra-specific and individual variations in resting metabolism, as shown in this study, potentially have a pronounced effect on the daily energy expenditure of a free-living animal. Accepted: 6 September 1996     

Out of Sight but Not Out of Mind? Behavioral Coordination in Red-Tailed Sportive Lemurs (<Emphasis Type="Italic">Lepilemur ruficaudatus</Emphasis>)

Many animals are organized into social groups and have to synchronize their activities to maintain group cohesion. Although activity budgets, habitat constraints, and group properties may impact on behavioural synchrony, little is known regarding how members of a group reach a consensus on the timing of activities such as foraging bouts. Game theory predicts that pair partners should synchronize their activities when there is an advantage of foraging together. As a result of this synchronization, differences in the energetic reserves of the two players develop spontaneously and the individual with lower reserves emerges as a pacemaker of the synchrony. Here, we studied the behavioral synchrony of pair-living, nocturnal, red-tailed sportive lemurs (Lepilemur ruficaudatus). We observed 8 pairs continuously for ≥1 annual reproductive cycle in Kirindy Forest, Western Madagascar. During focal observations, one observer followed the female of a pair and, simultaneously, another observer followed the male. We recorded the location and behavioral state of the focal individual every 5 min via instantaneous sampling. Although behavioral synchrony of pair partners appeared to be due mainly to endogenous activity patterns, they actively synchronized when they were in visual contact (<10 m). Nevertheless, red-tailed sportive lemurs benefit from synchronizing their activity only for 15% of the time, when they are close together. The lack of an early warning system for predators and weak support for benefits via social information transfer in combination with energetic constraints may explain why red-tailed sportive lemurs do not spend more time together and thus reap the benefits of behavioral synchrony.     

Defects in resting metabolic rates and mitochondrial respiration in Kwashiorkor and dietary obese rats

Summary Resting metabolic rates have been measured and compared with hepatic mitochondrial respiration in Kwashiorkor and diet-induced obese weaned rats. In Kwashiorkor, resting metabolic rate was 21% lower than the value of controls, while that of the obese rats was 14% higher than in control animals. The resting metabolic rate for Kwashiorkor animals was 50% of the predicted basal metabolic rate (BMR), whereas that of the obese rats was 23% higher than the predicted BMR. The mitochondrial oxygen consumption patterns, using malate plus glutamate or succinate as respiratory substrates, revealed that the resting respiration (state 4) was 23.9% higher in Kwashiorkor and 29.1% higher in obese animals, while the active (state 3) respiration was 34.8% lower in Kwashiorkor and 43.3% lower in obese rats compared to controls. The respiratory control ratios (RCR) were 51.1% and 43.8% in Kwashiorkor and obese rats, respectively, relative to the values in control rats. It is concluded from these studies that Kwashiorkor disease and diet-induced obesity appear to interfere with oxygen utilization at the level of state 3 mitochondrial respiration, which is markedly decreased when compared to the values for control animals.Abbreviations BMR basal metabolic rate - CPD commercially produced diet - KWD low protein, high carbohydrate diet - OBD high fat diet - PEM protein-energy malnutrition - RCR respiratory control ratios Present address: Department of Biochemistry, University of Nairobi, P.O. Box 30197, Nairobi, Kenya     

Energy metabolism, testosterone and corticosterone in white-crowned sparrows

The influence of the steroid hormones testosterone and corticosterone on energy metabolism and activity of birds is largely enigmatic. We measured resting metabolic rate during night and day in 12 long-term castrated and 12 intact male white-crowned sparrows (Zonotrichia leucophrys gambelii) under short-day (8:16 SD), long-day (20:4 LD), LD+testosterone implant and LD−testosterone implant conditions. Each male was sequentially measured under all four conditions. Photostimulation increased testosterone, resting metabolic rate, food intake, hopping activity and body mass in castrates and intact males. Surprisingly, testosterone levels and metabolic rates did not differ between intact and castrated males. Testosterone implantation increased activity and food intake, but decreased body mass and resting metabolic rate in both groups. Removing testosterone implants reversed the effects on resting metabolic rate, activity and food intake. Corticosterone levels, measured immediately at the end of metabolism measurements, showed birds were not stressed. Corticosterone had no apparent relationship with resting metabolic rate and there was no interaction between corticosterone and testosterone. Overall, positive changes in testosterone levels resulted in a decrease of resting metabolic rate. We speculate that testosterone increases activity, and birds compensate for increased activity metabolism by reducing resting metabolic rate. Accepted: 18 July 1999     

The effect of corticosterone on standard metabolic rates of small passerine birds

Summary Resting metabolic rates of Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) and pine siskins (Carduelis pinus) were evaluated at thermoneutral temperatures before and after administration of corticosterone (B) at physiological doses. There was no effect of B on basal metabolic rate of either species, but nocturnal metabolic rate varied significantly less over the 3-h period of measurement in B-treated sparrows and siskins than in control birds. These results, coupled with observations of caged birds, suggest that corticosterone has no direct effect on avian resting metabolism but does reduce the responsiveness of birds to external stimuli and thus promotes nocturnal restfulness.Abbreviations B corticosterone - VO ₂ rate of oxygen consumption - T ₃ tri-iodothyromine - T ₄ tetra-iodothyronine, thyroxine     

Osmotic and metabolic responses to dehydration and urea-loading in a dormant,terrestrially hibernating frog

Physiological responses to dehydration in amphibians are reasonably well documented, although little work has addressed this problem in hibernating animals. We investigated osmotic and metabolic responses to experimental manipulation of hydration state in the wood frog (Rana sylvatica), a terrestrial hibernator that encounters low environmental water potential during autumn and winter. In winter-conditioned frogs, plasma osmolality varied inversely with body water content (range 69–79%, fresh mass) primarily due to increases in sodium and chloride concentrations, as well as accumulation of glucose and urea. Decreased hydration was accompanied by a marked reduction in the resting rate of oxygen consumption, which was inversely correlated with plasma osmolality and urea concentration. In a separate experiment, resting rates of oxygen consumption in fully hydrated frogs receiving injections of saline or saline containing urea did not differ initially; however, upon dehydration, metabolic rates decreased sooner in the urea-loaded frogs than in control frogs. Our findings suggest an important role for urea, acting in concert with dehydration, in the metabolic regulation and energy conservation of hibernating R. sylvatica.     

Effects of feeding and habitat on resting metabolic rates of the Pacific walrus

Arctic marine mammals live in a rapidly changing environment due to the amplified effects of global warming. Pacific walruses (Odobenus rosmarus divergens) have responded to declines in Arctic sea-ice extent by increasingly hauling out on land farther from their benthic foraging habitat. Energy models can be useful for better understanding the potential implications of changes in behavior on body condition and reproduction but require behavior-specific metabolic rates. Here we measured the resting metabolic rates (RMR) of three captive, adult female Pacific walruses through breath-by-breath respirometry when fed and fasted resting out of water (sitting and lying down) and while fed resting in water. RMR in and out of water were positively related with pretrial energy intake when not fasted and 25% higher than RMR when walruses were fasted and out of water. Overall, RMR was higher than previously estimated for this species. Fasting RMR out of water was only 25% lower than subsurface swimming metabolic rates suggestive of relatively efficient swimming in adult females. Our results identify the importance of considering feeding status and species-specific differences in affecting metabolic costs. Further research is needed to better understand potential energetic costs of thermoregulation at temperatures experienced by wild walruses.     

Differences in basal energy expenditure and obesity

Objective: To assess the impact of differences in basal energy expenditure on adiposity. Research Methods and Procedures: Statistical analysis was performed on a published database giving anthropometric and energy expenditure measurements for 433 women and 335 men. Published equations derived by multiple regression analysis were used to predict basal metabolic rates in women and in men as a function of age, weight, and height. The differences between the observed and predicted rates (i.e., the residuals) were computed and expressed in terms of percentage deviation from the predicted rates of basal energy expenditure (BEE). In addition, individual body fat contents were computed using equations based on National Health and Nutrition Examination Study 3 data relating to body fat content determined by bioimpedance to BMI. Results: There is no correlation between percentage body fat content and deviations from predicted (which one would refer to as normal) BEE. Discussion: It can be concluded that relatively high or relatively low rates of BEE do not influence body weights and adiposity in a statistically identifiable manner. This contradicts and challenges the widely held view that low resting metabolic rates promote the development of obesity.     

Adenine nucleotide metabolism of blood platelets IX. Time course of secretion and changes in energy metabolism in thrombin-treated platelets

Changes in the energy metabolism of washed human platelets were compared with the kinetics of secretion induced by thrombin (5 units/ml). A 50% decrease in the level of metabolic ATP (³H-labelled), which was essentially complete in 30 s, was matched in rate by adenine nucleotide secretion from storage in dense granules. Incubation of platelets with antimycin before thrombin addition increased the rate of fall in metabolic ATP, but did not affect the rate of adenine nucleotide secretion. β-N-Acetylglucosaminidase secretion, which was slower than adenine nucleotide secretion in control platelets, was noticeably inhibited by antimycin, confirming previous reports that different regulatory mechanisms exist for dense and α-granule secretion. The rates of rephosphorylation of metabolic ADP to ATP via glycolysis and oxidative phosphorylation were estimated by measuring lactate production and O₂ consumption in resting and thrombin-stimulated platelets and compared to the level of metabolic ATP (9–10 nmol/mg of platelet protein in the resting state). The rate of ATP production was stimulated at least two fold from 12 nmol to 24 nmol/min/mg within seconds of thrombin addition. This increased rate was maintained over the observed period of 5 min although the level of metabolic ATP had decreased to 4–5 nmol/mg within 30 s; the turnover of the remaining metabolic ATP thus increased four fold over the resting state although the actual stimulation of energy production was only two fold.