Learned host preference in a Chagas disease vector, Rhodnius prolixus

Area of Science:

• Vector-borne diseases
• Insect behavior and cognition
• Parasitology

Background:

• Disease vector insects' individual experiences may influence host choice and parasite transmission.
• Speculation exists that vectors learn host defenses, altering preferences, but conclusive evidence in blood-sucking insects is limited.
• Recent studies show Rhodnius prolixus can associate neutral odors with rewards or punishments, altering their behavior.

Purpose of the Study:

• To investigate if Chagas disease vectors (triatomine bugs) alter host preference based on olfactory conditioning linked to negative experiences.
• To provide the first evidence of olfactory conditioning to host odors in triatomine bugs.

Main Methods:

• Naïve bugs were presented with odors from two different hosts without preference.
• Bugs were exposed to the odor of one host paired with a mechanical perturbation simulating defensive behavior.
• Post-exposure, bug preference between the two host odors was assessed.

Main Results:

• Naïve bugs showed no preference between the odors of two distinct hosts.
• Bugs conditioned with a negative experience (mechanical perturbation) associated with one host's odor subsequently avoided that host.
• This demonstrates a learned avoidance of a host based on its odor after a negative association.

Conclusions:

• This study provides the first evidence of olfactory conditioning to host odors in triatomine bugs, vectors of Chagas disease.
• Learned avoidance of hosts based on olfactory cues has significant implications for understanding and potentially controlling Chagas disease transmission.
• The findings contribute to the limited knowledge of associative learning and host preference in haematophagous insects.