Cockroach hosts in thermal gradients suppress parasite development

Area of Science:

• Parasitology
• Behavioral Ecology
• Invertebrate Zoology

Background:

• Parasitism can induce significant behavioral changes in hosts.
• The acanthocephalan parasite Moniliformis moniliformis is temperature-sensitive.
• Host behavioral alterations can impact parasite transmission and survival.

Purpose of the Study:

• To determine if cockroaches alter their thermal choices in response to Moniliformis moniliformis infection.
• To investigate if altered thermal choices by cockroaches affect parasite development.

Main Methods:

• Direct observation of cockroach behavior in thermal gradients.
• Indirect assessment of parasite development in infected cockroaches exposed to different temperature conditions.
• Comparison of parasite development in cockroaches with access to thermal gradients versus those at constant temperatures.

Main Results:

• Moniliformis moniliformis development was significantly retarded in two cockroach species (Supella longipalpa and Blatta orientalis) when allowed to choose temperatures.
• This retardation suggests infected cockroaches actively selected colder environments.
• Parasite development was less affected in cockroaches maintained at constant temperatures.

Conclusions:

• Cockroaches infected with Moniliformis moniliformis appear to alter their thermal preferences, likely by seeking cooler temperatures.
• This behavioral thermoregulation may serve as a defense mechanism against the parasite.
• Understanding host behavioral alterations is crucial for predicting parasite transmission dynamics.