Short-term cold acclimation influences Rhyzopertha dominica (Coleoptera: Bostrichidae) mobility in different...

Area of Science:

• Agricultural Entomology
• Insect Physiology
• Pest Management

Background:

• Stored product insects, like the lesser grain borer (Rhyzopertha dominica), pose significant threats to global food security.
• The ecology and behavior of these pests, particularly their locomotion, are critical for understanding colonization success and developing control strategies.
• Cold storage is a key management tactic, but insect acclimation can reduce its efficacy.

Purpose of the Study:

• To investigate the behavioral effects of short-term cold acclimation on the locomotion of Rhyzopertha dominica.
• To determine how temperature, sex, and strain influence the movement patterns of acclimated and non-acclimated lesser grain borers.
• To assess the implications of these behavioral changes for the effectiveness of cold storage pest control.

Main Methods:

• Quantified walking behavior of Rhyzopertha dominica across two strains (lab and wild) and sexes.
• Exposed insects to acclimation (18°C for 24h) versus no acclimation treatments.
• Recorded movement distances, immobility, and high-mobility events at three temperatures (10°C, 20°C, and 30°C) over one hour.

Main Results:

• Locomotion generally increased with temperature across all treatments.
• At 10°C, acclimated R. dominica exhibited increased movement and high-mobility events compared to non-acclimated individuals.
• At 20°C and 30°C, the pattern reversed, with non-acclimated insects showing greater movement; females and the lab strain generally moved more than males and the wild strain, respectively.

Conclusions:

• Short-term cold acclimation enhances locomotion at low temperatures but suppresses it at higher temperatures in R. dominica.
• Sex and strain significantly modulate these acclimation effects on insect movement.
• Careful application and monitoring of cold storage protocols are essential for maintaining effective grain protection against pests like R. dominica.