In a time with decreasing biodiversity, especially among insects, a detailed understanding about specific resource utilization strategies is crucial. The physiological and behavioural responses to host switches in phytophagous insects are poorly understood. Earlier studies indicate that a host plant switch might be associated with distinctive molecular and physiological responses in different lineages. Expanding the assessment of such associations across Lepidoptera will reveal if there are general patterns in adaptive responses, or if each switch event is more of a unique character. We investigated host plant preference, fitness consequences, effects on expression profiles and gut microbiome composition in two common wood white (Leptidea sinapis) populations with different host plant preferences from the extremes of the species distribution area (Sweden and Catalonia). Our results show that female Catalonian wood whites lack preference for either host plant (Lotus corniculatus or L. dorycnium), while Swedish females laid significantly more eggs on L. corniculatus. Individuals from both populations reared on L. dorycnium had longer developmental times and smaller body size as adults. This indicates that both environmental and genetic factors determine the choice to use a specific host plant. Gene expression analysis revealed a more pronounced response to host plant in the Catalonian compared to the Swedish population. In addition, host plant treatment resulted in a significant shift in microbiome community structure in the Catalonian population. Together, this suggests that population specific plasticity associated with local conditions underlies host plant utilisation in wood whites.

中文翻译：

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寄主植物饮食影响木白（Leptidea sinapis）蝴蝶的生长并诱导基因表达和微生物组组成的改变

在生物多样性减少的时代，特别是在昆虫中，详细了解具体的资源利用策略至关重要。植食性昆虫对宿主开关的生理和行为反应知之甚少。早期的研究表明，宿主植物转换可能与不同谱系中独特的分子和生理反应有关。扩大对鳞翅目这种关联的评估将揭示适应性反应中是否存在一般模式，或者每个转换事件是否更具独特性。我们研究了两种常见木白（Leptidea sinapis) 来自物种分布区（瑞典和加泰罗尼亚）极端的具有不同寄主植物偏好的种群。我们的研究结果表明，雌性加泰罗尼亚木白对任何一种寄主植物（Lotus corniculatus或L. dorycnium）都缺乏偏好，而瑞典雌性在 L.corniculatus 上产卵的数量明显更多。来自两个种群的个体都在L. dorycnium上饲养成年后的发育时间更长，体型更小。这表明环境和遗传因素都决定了使用特定寄主植物的选择。基因表达分析显示，与瑞典人口相比，加泰罗尼亚人对寄主植物的反应更为明显。此外，寄主植物处理导致加泰罗尼亚人群中微生物群落结构发生重大变化。总之，这表明与当地条件相关的种群特异性可塑性是木白中宿主植物利用的基础。