Parasitism-Mediated Interactions Between the Ring-Legged Earwig and Sugarcane Borer Larvae

Area of Science:

• Agricultural Entomology
• Biological Control
• Insect Ecology

Background:

• Sugarcane production in Brazil faces significant economic losses due to the sugarcane borer (SCB), Diatraea saccharalis.
• Conservation practices like no-tillage and prohibition of burning have increased natural enemy populations in sugarcane fields.
• Euborellia annulipes is a predator found in sugarcane fields, with known association with SCB predation.

Purpose of the Study:

• To evaluate the impact of Cotesia flavipes parasitism on the predatory behavior of Euborellia annulipes females towards Diatraea saccharalis larvae.
• To assess if parasitism influences E. annulipes feeding preference and functional response.
• To determine the potential of E. annulipes as a biological control agent for SCB.

Main Methods:

• Fourth instar D. saccharalis larvae were exposed to parasitism by C. flavipes or left unparasitized.
• Predatory assays were conducted under choice and no-choice conditions to evaluate feeding preference.
• Functional response of E. annulipes was assessed over 24 hours at varying prey densities.

Main Results:

• E. annulipes consumed 2-3 fourth instar SCB larvae within 12 hours.
• Parasitism by C. flavipes did not alter E. annulipes feeding preference or functional response type (Type II).
• Handling time for E. annulipes was lower on non-parasitized larvae, with a higher T/Th ratio.

Conclusions:

• Euborellia annulipes demonstrates potential as a biological control agent for Diatraea saccharalis.
• Parasitism by C. flavipes does not negatively impact E. annulipes predation efficiency.
• E. annulipes may offer a complementary strategy for SCB management, potentially reducing reliance on costly parasitoid releases.