Sphingid caterpillars conspicuous patches do not function as distractive marks or warning against predators

Area of Science:

• Ecology
• Evolutionary Biology
• Animal Behavior

Background:

• Caterpillars use cryptic or aposematic coloration for predator avoidance.
• The function of conspicuous patches on palatable caterpillars, like Eumorpha pandorus, is unclear.
• E. pandorus exhibits both cryptic and conspicuous color morphs and lateral patches.

Purpose of the Study:

• To investigate the role of coloration and conspicuous patches in E. pandorus caterpillar predation.
• To test the distractive mark and warning hypotheses for conspicuous patches.
• To analyze predator responses to different visual cues.

Main Methods:

• Field study in Massachusetts using plasticine caterpillar prey models.
• Four treatments: green/red models with/without lateral patches.
• Assessed attack rates by various predator taxa (arthropods, birds, rodents).

Main Results:

• 43% of models showed predator bite marks.
• Arthropods attacked green and non-patterned models more frequently.
• Vertebrates attacked red and patterned models more frequently.
• No evidence supported the distractive mark or warning hypotheses.

Conclusions:

• Conspicuous patch patterning did not reduce predation in E. pandorus.
• Predator responses to visual cues varied significantly between arthropods and vertebrates.
• Different predator groups interpret visual defensive strategies differently.