Some sawfly larvae survive predator-prey interactions with pentatomid Picromerus bidens

Area of Science:

• Entomology
• Chemical Ecology
• Predator-Prey Interactions

Background:

• Asopinae stinkbugs are predators of insects, including sawfly larvae.
• Sawfly families Argidae and Pergidae contain toxic peptides, but their defense against stinkbugs is understudied.
• Previous literature lacks specific laboratory tests on these sawfly-stinkbug interactions.

Purpose of the Study:

• To investigate the defensive capabilities of specific sawfly species against the predatory stinkbug Picromerus bidens.
• To determine if toxic peptides in Argidae and Pergidae sawflies deter stinkbug predation.
• To identify the primary defense mechanisms employed by these sawflies.

Main Methods:

• Laboratory bioassays were conducted using the stinkbug Picromerus bidens.
• Four sawfly species were tested: Arge ochropus, Arge pagana, Lophyrotoma zonalis, and Allantus rufocinctus.
• Predator-prey interactions were observed for 24-48 hours, noting survival rates and feeding behaviors.

Main Results:

• Allantus rufocinctus (Tenthredinidae) larvae did not survive predation.
• Argidae and Pergidae sawfly larvae survived encounters with Picromerus bidens, with limited feeding observed (6-20 seconds).
• Larger, older Arge pagana larvae were less frequently attacked, suggesting size and possibly developmental stage influence predation.

Conclusions:

• Argidae and Pergidae sawflies are likely well-defended against Picromerus bidens by potent internal antifeedants.
• Defensive body movements and larger body size play a secondary role in deterring stinkbug predation.
• This study highlights the chemical defenses of sawflies against specific insect predators.