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给个面子吧Gmat

月度遇到了JJ的恐龙和沼泽，双语，还有一个是两个理论关于鸟的某种行为（忘了。。）

billyisfragile!

是原文吗？

Abstract
Nest attentiveness (percentage of time spent on the nest) during incubation represents a parent‐offspring conflict; incubating birds must balance a trade‐off between caring for embryos by staying on the nest versus caring for themselves by getting off the nest to forage. For species in which females are the sole incubator, males can potentially affect this trade‐off and increase nest attentiveness by feeding incubating females on the nest (incubation feeding). Increased nest attentiveness may be required when local microclimate conditions are harsh and thereby require greater incubation feeding (microclimate hypothesis). Alternatively, incubation feeding may be constrained by risk of attracting nest predators (nest predation hypothesis), which in turn may constrain female nest attentiveness because of energy limitation. We show that incubation feeding rates are much greater among cavity‐nesting than among coexisting open‐nesting birds. Under the microclimate hypothesis, the greater incubation feeding rates of cavity‐nesting birds generate the prediction that microclimate should be harsher than for open‐nesting birds. Our results reject this hypothesis because we found the opposite pattern; cavity‐nesting birds experienced more moderate (less variable) microclimates that were less often below temperatures (i.e., 16°C) that can negatively impact eggs compared with open‐nesting species. In contrast, incubation feeding rates were highly negatively correlated with nest predation both within and between the two nest types, supporting the nest predation hypothesis. Incubation feeding in turn was positively correlated with nest attentiveness. Thus, nest predation may indirectly affect female incubation behavior by directly affecting incubation feeding by the male.

Avian embryos can suffer fitness costs such as increased mortality and reduced developmental rate with decreasing nest attentiveness (percentage of time that a parent sits on the nest) during incubation (White and Kinney 1974; Carey 1980; Lyon and Montgomerie 1985). Thus, high attentiveness should be a preferred state, possibly being somewhat relaxed in species with well-insulated nests (White and Kinney 1974). However, incubating birds are often constrained in their nest attentiveness because of limited energy resources (White and Kinney 1974; Martin 1987). Indeed, many birds require short recesses from the nest to obtain exogenous food resources to allow continued incubation. In the many species in which females incubate alone, males may reduce recesses and increase attentiveness by bringing food to incubating females and supplementing their energy resources. Such incubation feeding has been reported in a wide diversity of bird taxa (Lack 1940; Kendeigh 1952; Silver et al. 1985), and intraspecific studies have shown that greater incubation feeding can yield increased attentiveness (von Haartman 1958; Lyon and Montgomerie 1985; Lifjeld and Slagsvold 1986; Halupka 1994). Yet the influence of incubation feeding on nest attentiveness across species is unexamined despite the fact that incubation feeding rates and nest attentiveness vary extensively across species (e.g., Kendeigh 1952; Silver et al. 1985).

Given the fitness benefits of being attentive and the potential ability of incubation feeding to increase attentiveness, then an important question centers on why species vary in their rate of incubation feeding. One hypothesis suggests that greater incubation feeding is required in harsher microclimates to allow increased attentiveness because the fitness costs of leaving eggs unattended is greater (Lifjeld et al. 1987; Lyon and Montgomerie 1987; Nilsson and Smith 1988; Smith et al. 1989). Under this microclimate hypothesis, nest attentiveness and incubation feeding rates should be highest in species using nest sites that are exposed to extreme temperatures that can threaten embryo survival or reduce embryo developmental rates (Webb 1987; Haftorn 1988). An optimal temperature for embryo development is near 377 oC for passerines, but they may tolerate short exposures to temperatures between 167 and 417 oC, whereas temperatures outside this range affect embryo development and survival (Webb 1987). Indeed, Lyon and Montgomerie (1985) decreased nest attentiveness in female snow buntings (Plectrophenax nivalis) by removing male incubation feeding, which caused longer developmental (incubation) periods and increased mortality in an arctic environment where air temperatures often fell below 167 oC. Similarly, both Haftorn (1983) and Nilsson and Smith (1988) found reduced developmental rate and increased mortality when air temperatures fell below 167 oC. Thus, both incubation feeding and nest attentiveness should increase in species with nest sites where ambient temperatures increasingly fall outside of the 167–417 oC range.

给个面子吧Gmat

bzy! 发表于 2018-10-22 16:52
是原文吗？

Abstract

对的