Egg Predation by Phytoseiid Predatory Mites: Is There Intraguild Predation Towards Predatory Bug Eggs?

Area of Science:

• Agricultural Entomology
• Biological Control
• Predator-Prey Interactions

Background:

• Phytoseiid mites are key biocontrol agents against thrips pests.
• Previously, only immature thrips were considered vulnerable to phytoseiids.
• Recent findings indicate phytoseiids can prey on thrips eggs within leaf tissue.

Purpose of the Study:

• To evaluate the ability of three phytoseiid mite species to prey on thrips eggs.
• To determine if these phytoseiids also prey on the eggs of beneficial predatory bugs (mirids and anthocorids) that are inserted into plant tissue.
• To assess the impact of phytoseiid mites on the hatch rates of predatory bug eggs.

Main Methods:

• Tested Amblyseius swirskii, Transeius montdorensis, and Amblydromalus limonicus for their ability to prey on Frankliniella occidentalis eggs in leaf tissue.
• Assessed the predation of phytoseiids on eggs of Orius laevigatus, Macrolophus pygmaeus, and Nesidiocoris tenuis.
• Monitored the hatch rates of predatory bug eggs in the presence of phytoseiid mites.

Main Results:

• Amblyseius swirskii and Amblydromalus limonicus successfully preyed on thrips eggs.
• Transeius montdorensis showed no ability to prey on thrips eggs.
• Phytoseiid mites did not negatively affect the hatch rates of predatory bug eggs inserted in leaves.

Conclusions:

• Certain phytoseiid species, like A. swirskii and A. limonicus, offer potential for controlling thrips by consuming their eggs.
• The predatory behavior of these mites does not jeopardize populations of beneficial predatory bugs that share similar egg-laying habits.
• These findings enhance our understanding of phytoseiid mite efficacy in integrated pest management programs.