Sex-biased parasitism in vector-borne disease: Vector preference?

Area of Science:

• Ornithology
• Vector-borne disease ecology
• Animal behaviour

Background:

• Sex-biased infections are common in vertebrates, with males often more affected.
• Mechanisms include sex differences in immunity and differential exposure to parasites.
• Vector-borne diseases add complexity, as vectors may choose hosts based on cues.

Purpose of the Study:

• To investigate if the mosquito vector, Culex pipiens, is more attracted to male great tits (Parus major).
• To determine if intrinsic sex-based variation in nestlings influences mosquito host-seeking behaviour.
• To test the hypothesis that mosquito preference contributes to male-biased malaria infection in great tits.

Main Methods:

• Uninfected Culex pipiens mosquitoes were presented with a choice between uninfected male and female great tit nestlings.
• Mosquito feeding preference was assessed by analyzing the sex of the birds from which blood was ingested.
• Blood meal analysis used sex typing to identify the host source.

Main Results:

• No significant preference was observed for mosquitoes feeding on either male or female great tit nestlings.
• The results do not support the hypothesis that Culex pipiens is intrinsically attracted to male nestlings.
• Mosquitoes did not exhibit a sex-based preference during the nestling stage.

Conclusions:

• Mosquitoes do not appear to have an intrinsic preference for male great tit nestlings.
• The observed male-biased malaria infection in adult great tits may not be driven by nestling sex preference of the mosquito vector.
• Further research should investigate adult bird traits (e.g., behaviour, odour, metabolic rate) as potential factors influencing mosquito attraction.