Data from: Habitat heterogeneity favors asexual reproduction in natural populations of grassthrips

Explaining the overwhelming success of sex among eukaryotes is difficult
given the obvious costs of sex relative to asexuality. Different studies
have shown that sex can provide benefits in spatially heterogeneous
environments under specific conditions, but whether spatial heterogeneity
commonly contributes to the maintenance of sex in natural populations
remains unknown. We experimentally manipulated habitat heterogeneity for
sexual and asexual thrips lineages in natural populations and under
seminatural mesocosm conditions by varying the number of hostplants
available to these herbivorous insects. Asexual lineages rapidly replaced
the sexual ones, independently of the level of habitat heterogeneity in
mesocosms. In natural populations, the success of sexual thrips decreased
with increasing habitat heterogeneity, with sexual thrips apparently only
persisting in certain types of hostplant communities. Our results
illustrate how genetic diversity-based mechanisms can favor asexuality
instead of sex when sexual lineages co-occur with genetically variable
asexual lineages.

解释真核生物中性繁殖的压倒性优势为何存在颇具难度，这是因为相较于无性繁殖，有性繁殖存在显著的演化代价。已有多项研究表明，在特定条件下的空间异质性环境中，有性繁殖可带来演化优势，但空间异质性是否普遍能够促进自然种群中维持有性繁殖，目前仍不明确。本研究通过调控这类植食性昆虫可利用的寄主植物数量，在自然种群与半自然中型实验生态系统（mesocosm）环境中，对有性与无性蓟马谱系的生境异质性开展了实验操控。在中型实验生态系统中，无性谱系均能快速取代有性谱系，且与生境异质性水平无关。在自然种群中，有性蓟马的演化适合度随生境异质性提升而降低，且仅能在特定类型的寄主植物群落中存续。本研究结果表明，当有性谱系与遗传变异丰富的无性谱系共存时，基于遗传多样性的演化机制反而会倾向于选择无性繁殖而非有性繁殖。