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Reproductive Schedules (reproductive + schedule)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Mortality date estimation using fetal pronghorn remains

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1 2008
J. N. Fenner
Abstract Pronghorn (Antilocapra americana) fetal remains are sometimes recovered from archaeological contexts. Pronghorn have consistent reproductive schedules so their remains may provide information on seasonality of site occupation and number of mortality events. To investigate the reliability of fetal remains for seasonality and mortality event assessment, bone size and tooth eruption were measured in a sample of modern fetal pronghorn remains with known mortality dates. Results indicate a strong correlation between bone size and mortality date, but no significant correlation between tooth eruption level and mortality date. Fetal bone size was used to estimate a late April or early May mortality date at both the Oyster Ridge (48UT35) and Trappers Point (48SU1006) archaeological sites. The number of mortality events at Trappers Point was also investigated. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Energetic consequences of being a Homo erectus female

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2002
Leslie C. Aiello
Body size is one of the most important characteristics of any animal because it affects a range of behavioral, ecological, and physiological traits including energy requirements, choice of food, reproductive strategies, predation risk, range size, and locomotor style. This article focuses on the implications of being large bodied for Homo erectus females, estimated to have been over 50% heavier than average australopithecine females. The energy requirements of these hominins are modeled using data on activity patterns, body mass, and life history from living primates. Particular attention is given to the inferred energetic costs of reproduction for Homo erectus females based on chimpanzee and human reproductive scheduling. Daily energy requirements during gestation and lactation would have been significantly higher for Homo erectus females, as would total energetic cost per offspring if the australopithecines and Homo erectus had similar reproductive schedules (gestation and lactation lengths and interbirth intervals). Shortening the interbirth interval could considerably reduce the costs per offspring to Homo erectus and have the added advantage of increasing reproductive output. The mother would, however, incur additional daily costs of caring for the dependent offspring. If Homo erectus females adopted this reproductive strategy, it would necessarily imply a revolution in the way in which females obtained and utilized energy to support their increased energetic requirements. This transformation is likely to have occurred on several levels involving cooperative economic division of labor, locomotor energetics, menopause, organ size, and other physiological mechanisms for reducing the energetic load on females. Am. J. Hum. Biol. 14:551,565, 2002. © 2002 Wiley-Liss, Inc. [source]

Activity budgets and activity rhythms in red ruffed lemurs (Varecia rubra) on the Masoala Peninsula, Madagascar: seasonality and reproductive energetics

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2005
Natalie Vasey
Abstract The activity budgets and daily activity rhythms of Varecia rubra were examined over an annual cycle according to season and reproductive stage. Given the relatively high reproductive costs and patchy food resources of this species, I predicted that V. rubra would 1) travel less and feed more during seasonal resource scarcity in an attempt to maintain energy balance, and 2) show sex differences in activity budgets due to differing reproductive investment. Contrary to the first prediction, V. rubra does not increase feeding time during seasonal food scarcity; rather, females feed for a consistent amount of time in every season, whereas males feed most during the resource-rich, hot dry season. The results are consistent with other predictions: V. rubra travels less in the resource-scarce cold rainy season, and there are some pronounced sex differences, with females feeding more and resting less than males in every season and in every reproductive stage except gestation. However, there are also some provocative similarities between the sexes when activity budgets are examined by reproductive stage. During gestation, female and male activity budgets do not differ and appear geared toward energy accumulation: both sexes feed and rest extensively and travel least during this stage. During lactation, activity budgets are geared toward high energy expenditure: both sexes travel most and in equal measure, and rest least, although it remains the case that females feed more and rest less than males. These similarities between female and male activity budgets appear related to cooperative infant care. The high energetic costs of reproduction in V. rubra females may require that they allot more time to feeding year round, and that their overall activity budget be more directly responsive to seasonal climate change, seasonal food distribution, and reproductive schedules. Am. J. Primatol. 66:23,44, 2005. [source]

Life history evolution in a globally invading tephritid: patterns of survival and reproduction in medflies from six world regions

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009
ALEXANDROS D. DIAMANTIDIS
Comparisons among populations from different localities represent an important tool in the study of evolution. Medflies have colonized many temperate and tropical areas all over the world during the last few centuries. In a common garden environment, we examined whether medfly populations obtained from six global regions [Africa (Kenya), Pacific (Hawaii), Central America (Guatemala), South America (Brazil), Extra-Mediterranean (Portugal) and Mediterranean (Greece)] have evolved different survival and reproductive schedules. Whereas females were either short-lived [life expectancy at eclosion (e0) 48,58 days; Kenya, Hawaii and Guatemala] or long-lived (e0 72,76 days; Greece, Portugal and Brazil], males with one exception (Guatemala) were generally long-lived (e0 106,122 days). Although males universally outlived females in all populations, the longevity gender gap was highly variable (20,58 days). Lifetime fecundity rates were similar among populations. However, large differences were observed in their age-specific reproductive patterns. Short-lived populations mature at earlier ages and allocate more of their resources to reproduction early in life compared with long-lived ones. In all populations, females experienced a post-reproductive lifespan, with this segment being significantly longer in Kenyan flies. Therefore, it seems plausible that medfly populations, inhabiting ecologically diverse habitats, have evolved different life history strategies to cope with local environmental conditions. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 106,117. [source]