Assortative mating in Ixodes scapularis Say, 1821 (Acari: Ixodidae)

Area of Science:

• Evolutionary Biology
• Population Genetics
• Behavioral Ecology

Background:

• Mate choice significantly impacts population genetic diversity and inbreeding levels.
• Positive assortative mating (PAM) is known in Ixodes ricinus but unstudied in Ixodes scapularis.
• Understanding mate choice in Ixodes scapularis is crucial due to its role as a disease vector.

Purpose of the Study:

• To investigate the presence and extent of positive assortative mating (PAM) in Ixodes scapularis.
• To analyze genetic relatedness within mating pairs of Ixodes scapularis.
• To explore potential genetic mechanisms underlying mate choice in this tick species.

Main Methods:

• Analysis of nine microsatellite loci from 30 female and 30 male Ixodes scapularis ticks.
• Ticks were collected in copula from deer at the Savannah River Site, South Carolina.
• Statistical analysis to detect assortative pairing signatures and assess genetic homogeneity.

Main Results:

• A weak but statistically significant positive assortative mating (PAM) signature was identified.
• The Ixodes scapularis population exhibited overall genetic homogeneity.
• Observed mating pairs showed a significant difference in relatedness compared to all other possible pairs.

Conclusions:

• Ixodes scapularis exhibits positive assortative mating (PAM), indicating non-random mate selection.
• Non-coding microsatellite loci may be linked to genes influencing PAM through genetic hitchhiking.
• The genetic architecture for PAM likely involves a combination of major and minor effect genes distributed across the genome.