Nhận biết (M1)

The bird species Saltator grossus (the slate-colored grosbeak), which weighs about 45 grams, and Microbates collaris (the collared gnatwren), which weighs about 10 grams, share territory in French Guiana with Thamnomanes caesius (the cinereous antshrike), which emits a loud alarm call when it detects predators. Biologist Ari Martínez and colleagues, who studied the ecological community these species share, hypothesized that since there is an inverse relationship between body size and vulnerability to predation, there will also be an inverse relationship between body size and sensitivity to predator warning signals from neighboring species.

Which finding, if true, would most directly support Martinez and colleagues' hypothesis?

• A.

  When Martinez and colleagues played T. caesius alarm calls, only bird species larger than S. grossus displayed predator-avoidance behavior.

• B.

  M. collaris displayed predator-avoidance behavior when Martinez and colleagues played T. caesius alarm calls as well as when the researchers played control sounds of random noise.

• C.

  Many bird species smaller than S. grossus displayed predator-avoidance behavior in response to T. caesius alarm calls played by Martínez and colleagues, but none smaller than M. collaris did.

• D.

  M. collaris displayed predator-avoidance behavior in response to T. caesius alarm calls played by Martínez and colleagues, whereas S. grossus did not.