Thermal control of maternal contact bouts: The interbout interval

Bates, Andrea; Adels, Lori; Leon, Michael

doi:10.1016/0031-9384(85)90386-5

Cited by 10 publications

(5 citation statements)

References 12 publications

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“…In addition to this strongly supportive evidence for the HDL theory from large domesticated mammals, there is also a diverse literature on factors that affect maternal suckling behaviour in rodents. These data indicate that a key factor influencing maternal suckling duration is the risk of the mother overheating during the suckling bout (Leon et al, 1978;Leon et al, 1983;Bates et al, 1985;Leon et al, 1985;Adels and Leon, 1986;Newkirk et al, 1998). Further support for the HDL theory comes from comparisons of the reproductive performance of mice selectively bred to enhance their capacity to dissipate heat (Nielsen et al, 1997a;Nielsen et al, 1997b;Kgwatalala et al, 2004;McDonald and Nielsen, 2006).…”

Section: New Ideas On Limits To Sustained Energy Intakementioning

confidence: 97%

Limits to sustained energy intake. XIII. Recent progress and future perspectives

Speakman

Król

2011

Journal of Experimental Biology

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Summary Several theories have been proposed to explain limits on the maximum rate at which animals can ingest and expend energy. These limits are likely to be intrinsic to the animal, and potentially include the capacity of the alimentary tract to assimilate energy – the ‘central limitation’ hypothesis. Experimental evidence from lactating mice exposed to different ambient temperatures allows us to reject this and similar ideas. Two alternative ideas have been proposed. The ‘peripheral limitation’ hypothesis suggests that the maximal sustained energy intake reflects the summed demands of individual tissues, which have their own intrinsic limitations on capacity. In contrast, the ‘heat dissipation limit’ (HDL) theory suggests that animals are constrained by the maximal capacity to dissipate body heat. Abundant evidence in domesticated livestock supports the HDL theory, but data from smaller mammals are less conclusive. Here, we develop a novel framework showing how the HDL and peripheral limitations are likely to be important in all animals, but to different extents. The HDL theory makes a number of predictions – in particular that there is no fixed limit on sustained energy expenditure as a multiple of basal metabolic rate, but rather that the maximum sustained scope is positively correlated with the capacity to dissipate heat.

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Section: New Ideas On Limits To Sustained Energy Intakementioning

confidence: 97%

Limits to sustained energy intake. XIII. Recent progress and future perspectives

Speakman

Król

2011

Journal of Experimental Biology

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“…For example, the body temperatures at which rats discontinue suckling are generally lower than the levels they tolerate while exercising outside the nest (Kittrell & Satinoff 1988). Perhaps more important are experimental inductions of reduced body temperature using sodium salicylate, which did not extend suckling bouts (Bates et al 1985). Although treatment of lactating rats with morphine simultaneously elevates body temperature and disrupts maternal suckling (above), the negative effect of morphine appears to be independent of its effects on body temperature.…”

Section: Indirect Costs (A) Optional Compensatory Costs (I) Thermoregmentioning

confidence: 99%

The physiological costs of reproduction in small mammals

Speakman

2007

Phil. Trans. R. Soc. B

642

694

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Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional 'compensatory costs' whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.

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“…An alternative explanation was proposed by Croskerry et al [40] suggesting that contact with pups in the nest induces maternal hyperthermia and serves as a constraint on the amount of time a dam may spend on her nest. This hypothesis has received much attention, and evidence both for and against it has been gathered from various species [41-43, but see 44-46]. Our data indicate that contact with pups did not correlate with peaks in T b in lactating grass rats.…”

Section: Discussionmentioning

confidence: 55%

Changing patterns of daily rhythmicity across reproductive states in diurnal female Nile grass rats (Arvicanthis niloticus)

Schrader

Walaszczyk

Smale

2009

Physiology & Behavior

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SCHRADER, J.A., E. J. WALASZCZYK, AND L. SMALE. Changing patterns of daily rhythmicity across reproductive states in diurnal female Nile grass rats (Arvicanthis niloticus). PHYSIOL BEHAV XX(X) XXX-XXX, XXXX. -- A suite of changes in circadian rhythms have been described in nocturnal rodents as females go through pregnancy and lactation, but there is no information on such patterns in diurnal species. As the challenges faced by these two groups of animals are somewhat different, we characterized changes in activity and core body temperature (Tb) in female diurnal Nile grass rats (Arvicanthis niloticus) as they went through a series of reproductive states: virgin, pregnant, pregnant and lactating, lactating only, and post-weaning. The phase of neither rhythm varied, but the amplitude did. Females increased their overall levels of daily activity from early to late pregnancy, regardless of whether they were also lactating. The pattern of activity was less rhythmic during early than mid-lactation, in both non-pregnant and pregnant females, as a consequence of a decrease in daytime relative to nighttime activity. The Tb rhythm amplitude dropped from mid-pregnancy through mid-lactation, and there were rises in Tb troughs during the mid-light and mid-dark phases of the day, though pregnancy and lactation affected Tb at these times in somewhat different ways. This study demonstrates that rhythms in diurnal grass rats change during pregnancy and lactation in different ways than those of nocturnal species that have been studied to date and that the effects of pregnancy and lactation are not additive in any simple way.

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Thermal control of maternal contact bouts: The interbout interval

Cited by 10 publications

References 12 publications

Limits to sustained energy intake. XIII. Recent progress and future perspectives

Limits to sustained energy intake. XIII. Recent progress and future perspectives

The physiological costs of reproduction in small mammals

Changing patterns of daily rhythmicity across reproductive states in diurnal female Nile grass rats (Arvicanthis niloticus)

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