Intraguild Predation in Heteroptera: Effects of Density and Predator Identity on Dipteran Prey

Area of Science:

• Ecology
• Aquatic Entomology
• Predator-Prey Dynamics

Background:

• Water bugs (Heteroptera) in tropical freshwaters form guilds that share prey resources like chironomid and mosquito larvae.
• Intraguild predation (IGP) is a potential interaction within these guilds, influencing prey mortality and community structure.

Purpose of the Study:

• To evaluate the effects of predator and prey density on the mortality of shared prey (mosquito and chironomid larvae).
• To assess the roles of Laccotrephes griseus and Ranatra filiformis as intraguild predators and Anisops bouvieri as an intraguild prey.

Main Methods:

• Experimental manipulation of predator density and combinations of L. griseus and R. filiformis.
• Observation of predation rates on mosquito and chironomid larvae.
• Analysis of Anisops bouvieri mortality in relation to shared prey density.

Main Results:

• Predation on larvae varied significantly with predator density and species composition; L. griseus showed a greater impact than R. filiformis.
• The mortality of A. bouvieri was significantly affected by shared prey density.
• The presence of A. bouvieri as an intermediate predator potentially interfered with predation on dipteran larvae.

Conclusions:

• Intraguild predator species composition and density are critical factors in regulating prey populations in tropical freshwater ecosystems.
• The interactions among these heteropteran predators are not substitutable and have independent effects, impacting mosquito biological control strategies.
• Under low prey density, the presence of intraguild predators, including A. bouvieri, may inadvertently benefit dipteran prey.