Field evidence for non-host predator avoidance in a manipulated amphipod

Area of Science:

• Ecology
• Parasitology
• Behavioral Ecology

Background:

• Manipulative parasites alter host behavior and distribution for transmission.
• Field data on parasite-induced spatial shifts and their impact on predator-prey interactions are scarce.
• Understanding parasite effects on host spatial ecology is crucial for community dynamics.

Purpose of the Study:

• Investigate how manipulative parasite infection affects the predation risk of intermediate hosts by non-host predators.
• Examine the spatial coexistence between infected prey and dead-end predators.
• Provide field evidence for parasite-induced habitat shifts and their ecological consequences.

Main Methods:

• Field sampling of invertebrates across various natural habitats.
• Quantified habitat breadth of amphipods (Gammarus roeseli) based on infection status with Polymorphus minutus.
• Assessed macro-invertebrate community overlap to estimate predation risk for infected and uninfected amphipods.

Main Results:

• Infection with P. minutus significantly reduced the habitat breadth of G. roeseli.
• Parasitized G. roeseli were primarily found in floating materials, unlike widespread uninfected conspecifics.
• Habitat overlap analysis indicated a lower spatial encounter probability between P. minutus-infected G. roeseli and invertebrate predators.

Conclusions:

• Parasite-induced habitat shifts in G. roeseli lead to spatial avoidance by dead-end invertebrate predators.
• This study provides novel field evidence for the ecological implications of manipulative parasite behavior.
• The findings highlight the importance of considering parasite-host spatial dynamics in ecological interactions.