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11.
Predation is often considered an important factor in the evolution of sociality among animals. We studied mortality patterns and grouping behavior of white-nosed coatis (Nasua narica) at sites in southern Arizona, USA, and western Jalisco, México. Coatis were monitored by radio-tracking and recaptures for more than 3 years at each site. In both populations, predation by large felids, including jaguars (Panthera onca) and pumas (Puma concolor), accounted for more than 50% of mortality of adult coatis. Predation rates were significantly higher on solo coatis than on coatis in groups at both study sites. Predation rates were negatively related to group size in Arizona. However, mortality of juveniles, as measured by the ratios of juveniles to adult females, was not related to the number of adult females per group in Arizona or Jalisco. Coatis exhibit a suite of behaviors, including foraging with the juveniles in the center of the group, sharing vigilance, alarm calling, mobbing and attacking predators, and a highly synchronous birth season, that are all consistent with the hypothesis that predation has played an important role in shaping coati social behavior. 相似文献
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John T. Hogg Christine C. Hass Donald A. Jenni 《Behavioral ecology and sociobiology》1992,31(4):243-251
Summary We examined maternal energy expenditure in Rocky Mountain bighorn sheep to test the hypothesis (Trivers and Willard 1973) that individual sons in polygynous mammals should obtain a larger maternal subsidy. In accord with theory, males weighed more at birth (an index of relative prenatal expenditure), tended to suckle more between 40 and 100 days of age (an index of relative postnatal expenditure) and imposed greater delays on their mothers' return to estrus in the subsequent breeding season (an index of relative total preweaning expenditure). Mothers rather than offspring appeared to have primary control over postnatal expenditure. The effect of maternal reproductive effort on return to estrus was cumulative over a period of 3–5 years so that ewes making relatively large expenditures gave birth progressively later. Ewe and lamb mortality was associated with late conception in the previous rut. Thus, differential reproductive effort by ewes in this population appeared to entail a fitness cost involving reductions in both offspring and maternal survivorship.
Correspondence to: J.T. Hogg at the present address 相似文献
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Chia-Yang Chen Jonathan T. Hamm J. Ronald Hass Phillip W. Albro Linda S. Birnbaum 《Chemosphere》2002,46(9-10)
Pregnant Long Evans rats received 1.0 μg/kg of dioxin toxic equivalents (TEQ) by oral gavage on the 15th gestational day (GD 15), using a dosing mixture that contained two polychlorinated dioxins, four polychlorinated furans and three non-ortho polychlorinated biphenyls (PCBs). Rats were sacrificed on GD 16, GD 21 and postnatal day 4 (PND 4). The lipid content of fetus, pup, placenta and maternal liver, serum and adipose tissue were determined. Treated GD 16 and GD 21 fetuses had identical lipid content to the control group, yet the lipid content of treated pups on PND 4 was 32% higher than that of the control group. On the other hand, the lipid content of placenta, liver, and serum from the treated dams was 44–50%, 24%, and 38% lower than that of the control group, respectively. Thus, a low-dose mixture of dioxin-like compounds can cause changes in lipid content. The lipid content of offspring was not affected until they were exposed via lactation. 相似文献
14.
An analytical protocol for the measurement of part per billion and sub-part per billion levels of PBDDs and PBDFs in selected flame retardant chemicals (polybrominated diphenyloxides; PBDPO) was developed. The fractionation/enrichment procedures were optimized to minimize the effects of the PBDPOs upon the ability to recover and measure the PBDD/PBDFs. Results from the method validation show that the current methodology is capable of accuracies ranging from 70% to 150% at the 0.1 to 10 ppb levels while larger sample sizes (from 20–200 mg to 4 g) are necessary in order to meet the EPA target Test Rule limit of quantification (LOQ) requirements. 相似文献
15.
Phillip W. Albro J. Ronald Hass Carl C. Peck Sandra T. Jordan Jean T. Corbett Joanna Schroeder 《Journal of environmental science and health. Part. B》2013,48(6):701-714
Abstract The pervasiveness of the plasticizer di‐(2‐ethylhexyl) phthalate (DEHP) in the environment and especially in the laboratory results in a background that may cause severe interference with analytical studies. Animal‐to‐animal variability in the distribution of DEHP metabolites in excreta normally makes it necessary to use large groups of animals when different treatments are compared. Finally, radioactive tracers are usually considered undesirable for metabolic studies involving human subjects. All of these problems can be overcome through the use of muliple isotopic labels, especially 12C/13C/14C. Examples are given involving rats and monkeys, and applicability to humans is discussed. The principles involved are not limited to any particular class of test compounds. In rats, the competing pathways for metabolism of phthalate esters produce a different distribution of metabolites from a small intravenous dose of DEHP than from a large oral dose. 相似文献
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Rodolfo Salm Lisa Feder Mario Augusto Gonçalves Jardim Nefertiti Hass Euphly Jalles-Filho Ana Maria Costa 《Environment, Development and Sustainability》2009,11(1):161-173
In a meeting between FUNAI (the Brazilian Indian National Foundation) and the Kayapo in the Kayapo village of Aukre, in October
2005, the Kayapo Indians requested support to increase the culture of coconuts (Cocos nucifera) in their lands. The introduction of exotic species is a cause of biological diversity loss throughout the world. However,
this is by no means applicable to all kinds of exotic species. We argue that the culture of coconuts may actually be a useful
tool for the conservation of this country’s indigenous lands, despite criticism to the contrary. It may also be useful as
source for raw material for the indigenous people who are presently experiencing a population boom. For the Kayapo of south-eastern
Amazonia, such a demographic explosion, coupled with their increasing dependence on money to purchase industrialized goods,
tend to substantially increase the pressure on their lands, which still contain a substantial amount of well-preserved seasonally-dry
Amazonian forests. We investigated the actual economic relevance of coconuts for the Kayapo by measuring human and coconut
populations and found that this exotic palm is not important for the subsistence of these Indians, due to coconut scarcity,
and that such importance is not forthcoming. In the Amazon, coconuts may be particularly useful for the Indians’ nutrition
due to the high energetic value of the solid endosperm of the mature fruit. Therefore, given the importance of indigenous
lands for the conservation of the Amazonian forests, the encouragement of subsistence coconut cultures in indigenous lands
is defensible as a measure for the conservation of biodiversity. 相似文献