Lack of Torpor in Free-Ranging Southern Lesser Galagos, Galago moholi: Ecological and Physiological Considerations

Mzilikazi, Nomakwezi; Masters, Judith; Lovegrove, Barry G.

doi:10.1159/000095392

Cited by 55 publications

(26 citation statements)

References 36 publications

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“…We then averaged the ten IORs to achieve an average IOR between the two observers (89.9 ± SE 0.03 %). Although free-ranging populations from both sites were accustomed to humans, due to previous biological studies (NNR; Mzilikazi et al 2006;Nowack et al 2010;Nowack et al 2013;Pullen et al 2000) or frequent human interaction (OP), observers were never closer than five metres to an individual being followed.…”

Section: Ad Libitum Followsmentioning

confidence: 99%

The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby

Scheun

Bennett

Ganswindt

et al. 2015

Sci Nat

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Urbanisation has become a severe threat to pristine natural areas, causing habitat loss and affecting indigenous animals. Species occurring within an urban fragmented landscape must cope with changes in vegetation type as well as high degrees of anthropogenic disturbance, both of which are possible key mechanisms contributing to behavioural changes and perceived stressors. We attempted to elucidate the effects of urbanisation on the African lesser bushbaby, Galago moholi, by (1) recording activity budgets and body condition (body mass index, BMI) of individuals of urban and rural populations and (2) further determining adrenocortical activity in both populations as a measure of stress via faecal glucocorticoid metabolite (fGCM) levels, following successful validation of an appropriate enzyme immunoassay test system (ACTH challenge test). We found that both sexes of the urban population had significantly higher BMIs than their rural counterparts, while urban females had significantly higher fGCM concentrations than rural females. While individuals in the urban population fed mainly on provisioned anthropogenic food sources and spent comparatively more time resting and engaging in aggressive interactions, rural individuals fed almost exclusively on tree exudates and spent more time moving between food sources. Although interactions with humans are likely to be lower in 2 nocturnal than in diurnal species, our findings show that the impact of urbanisation on nocturnal species is still considerable, affecting a range of ecological and physiological aspects.

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Section: Ad Libitum Followsmentioning

confidence: 99%

The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby

Scheun

Bennett

Ganswindt

et al. 2015

Sci Nat

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“…To emphasize the flexibility of the HI approach, we made no attempt to standardize the period analyzed. Data are from Kortner and Geiser (1998), Park et al (2000), Mzilikazi and Lovegrove (2004), Munro et al (2005), Mzilikazi et al (2006), and Hetem et al (2009). possible way to compare heterothermy between adults and juveniles is with the minimum T b . However, this may miss important temporal patterns, such as the time spent below T b-opt .…”

Section: Comparing Intraspecific Patterns Of Thermoregulationmentioning

confidence: 99%

A New Comparative Metric for Estimating Heterothermy in Endotherms

Boyles

Smit

McKechnie

2011

Physiological and Biochemical Zoology

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A major focus in the study of endothermic thermoregulation has been the description of thermoregulatory patterns used by various species and/or populations. Compared with ectotherms, relatively few attempts have been made to study the thermoregulation of endotherms in an adaptive framework. We believe that one of the main factors limiting this area of research has been the lack of an appropriate metric to directly compare body temperature (T b ) variation across all endothermic species. Thus, we present a simple comparative metric, the heterothermy index (HI), to quantify the expression of heterothermy by endotherms during a given time frame. Key advantages of HI are that (1) it represents a new analytical technique that has different strengths than the metrics commonly used to describe variation in T b , (2) it allows for evaluation of nonenergetic costs and benefits that affect the expression of heterothermy, and (3) it has the potential to unify research on homeotherms and heterotherms through quantitative comparative analyses that examine the entire continuum of thermoregulatory patterns. In short, we suggest that our metric provides a means to overcome one of the hurdles presently slowing the advancement of research on endothermic thermoregulation beyond the simple description of thermoregulatory patterns.

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“…Morrison & Middleton, ) exhibit pronounced circadian cycles in T b , decreasing their T b during the daily resting phase and thereby saving energy (e.g. M. murinus : Ortmann et al ., ; Cheirogaleus medius : Dausmann et al ., ; Galago senegalensis , G. demidovii : Dobler, ; G. crassicaudatus : Müller & Jaschke, ; G. moholi : Mzilikazi, Masters & Lovegrove, ; N. coucang : Müller, ).…”

Section: Introductionmentioning

confidence: 99%

Flexible patterns in energy savings: heterothermy in primates

Dausmann

2014

Journal of Zoology

102

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Heterothermy is an energy‐saving strategy usually employed in response to environmental bottlenecks, which is common in almost all mammalian orders. Within the order primates, heterothermy has been physiologically confirmed only in the family Cheirogaleidae (Cheirogaleus, Microcebus, Allocebus, Mirza) of the Malagasy lemurs, and the southern lesser bushbaby (Galago moholi) of the family Galagonidae. These closely related species employ a spectrum of daily torpor, prolonged torpor and obligate hibernation under tropical, but nevertheless seasonal and energetically demanding conditions. There is a remarkable physiological flexibility in regard to their thermoregulatory adaptations not only between species of the same genera within one habitat, but also between populations of the same species, within populations and even within the same individual, permitting immediate responses in seasonal and unpredictable environments, and possibly aiding these species to master challenges of globally changing climatic conditions. Whereas heterothermy is a flexible, but regular seasonal response in the Cheirogaleidae, it is only used as a last emergency strategy in G. moholi. In the other primate species, there is either no or only anecdotal evidence of only minor reductions in metabolic rate, presumably rather reflecting pronounced circadian cycles in body temperature, or local heterothermy. Maybe because of their relatively high degree of sociality and larger body sizes, behavioural and ecological adaptations to seasonality are selected for in other primates.

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Lack of Torpor in Free-Ranging Southern Lesser Galagos, Galago moholi: Ecological and Physiological Considerations

Cited by 55 publications

References 36 publications

The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby

The hustle and bustle of city life: monitoring the effects of urbanisation in the African lesser bushbaby

A New Comparative Metric for Estimating Heterothermy in Endotherms

Flexible patterns in energy savings: heterothermy in primates

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