Do plant trichomes cause more harm than good to predatory insects?

Area of Science:

• Plant Biology
• Entomology
• Ecology

Background:

• Plants utilize trichomes as physical defenses against herbivore damage.
• Predatory insects are crucial for biological control of herbivores.
• The impact of plant trichomes on beneficial predators requires investigation.

Purpose of the Study:

• To test the hypothesis that trichome-bearing plants do not cause more harm than good to predators.
• To synthesize existing literature on plant trichome-predator interactions.
• To evaluate the net effect of trichomes on predator populations and plant fitness.

Main Methods:

• Literature review of 47 records on plant trichome and predatory insect interactions.
• Analysis of documented effects of trichomes on predator behavior, development, and survival.
• Comparison of trichome density and cultivar effects on predator harm.

Main Results:

• Plant trichomes predominantly exert harmful effects on predatory insects.
• Harmful effects include impaired movement, development, oviposition, and predation.
• Glandular trichomes can entrap predators, while non-glandular trichomes can impale them, leading to mortality.
• High trichome density, particularly in tomato and bean cultivars, causes significant harm to predatory beetles, true bugs, and lacewings.

Conclusions:

• Plant trichomes often cause more harm than good to key predatory insects.
• The sublethal effects of trichomes on predators can negatively impact biological control.
• Future research should assess the net effect of trichomes on plant fitness and predator-mediated herbivore suppression.
• Developing pest-resistant cultivars requires careful consideration of trichome-induced impacts on beneficial predator populations.