Reciprocal intraguild predation and predator coexistence | JoVE Visualize

Area of Science:

Ecology
Predator-prey dynamics
Interspecific interactions

Background:

Intraguild predation, where one species preys on another sharing resources, often hinders species coexistence.
Despite theory, intraguild predation is common, suggesting factors like habitat complexity and alternative food may facilitate coexistence.
Reciprocal intraguild predation further complicates coexistence, yet these factors are proposed to mitigate its effects.

Purpose of the Study:

To investigate how habitat complexity and alternative food sources influence the coexistence of two intraguild predatory mite species.
To determine if reciprocal intraguild predation occurs between *Iphiseiodes zuluagai* and *Euseius concordis*.
To assess the impact of spatial structure and food availability on the long-term coexistence of these mite species.

Main Methods:

Field observations of co-occurrence between *Iphiseiodes zuluagai* and *Euseius concordis*.
Laboratory experiments using arenas with varying spatial structures and food availability to simulate natural conditions.
Monitoring predator-prey interactions, including attacks on juveniles and adults, and population dynamics under different experimental setups.

Main Results:

The two predatory mite species, *Iphiseiodes zuluagai* and *Euseius concordis*, were found to co-occur in the field.
Laboratory studies confirmed reciprocal intraguild predation, with adults of each species preying on the other's juveniles, and *I. zuluagai* adults also attacking *E. concordis* adults.
*Euseius concordis* rapidly went extinct in simple arenas without spatial structure or alternative food.
Coexistence duration increased with alternative food sources, but extinction still occurred.
On complex, intact plants, coexistence was significantly prolonged, with *I. zuluagai* often going extinct, suggesting spatial structure is crucial.

Conclusions:

Spatial structure and the availability of alternative food sources are critical factors that can extend the coexistence period of intraguild predators.
These findings challenge the notion that intraguild predation invariably leads to extinction, highlighting the importance of habitat characteristics in mediating species interactions.
The study demonstrates that complex habitats can facilitate the coexistence of species engaged in reciprocal intraguild predation, a significant finding for ecological theory and conservation.