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Concept/Content kin selection / Belding ground squirrel (Spermophilus beldingi)
Information caption In Belding's ground squirrels (Spermophilus beldingi), which inhabit mountain meadows in the western U.S., exhbit costly helping, in the form of alarm calls as sentinels watch for predators. Unlike meerkats, Belding's ground squirrels that raise an alarm are more frequently preyed upon. In this case, the ground squirrels in one area tend to be closely related. They alert and benefit mostly their kin. Relatedness among individuals varies, however, and underlies significant differences in calling behavior. Males tend to disperse from their place of birth, while females remain local. Females thus have more kin neighbors than males do and, accordingly, they devote more time to the sentinel role. In addition, their alarm calls are more numerous when only close relatives are nearby. While alarm calls in general seem to have evolved based on foraging in the open during the day, the pattern and frequency of sentinel risks in the Belding's ground squirrels seems to reflect kin selection (Sherman 1977; Shelley and Blumstein 2004).
Inquiry caption Belding's ground squirrels (Spermophilus beldingi) inhabit mountain meadows in the western U.S. Helping behavior appears in the alarm calls of sentinels watching for predators, an evolutionary result of foraging in the open during the day. Unlike meerkats, however, Belding's ground squirrels that raise an alarm are more frequently preyed upon. Their social system also differs. Males tend to disperse from their place of birth, while females remain in the local area. How might this affect the selection of sentinel behavior?
[Females have more kin neighbors than do males and, accordingly, they devote more time to the sentinel role. In addition, their alarm calls are more numerous when only close relatives are nearby (Sherman 1977; Shelley and Blumstein 2004).]
Target Concept: Some cases of costly helping are explained by genetic relatedness.
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Credit public domain [wikipedia]
SIZE in pixels [file size] 446x543

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