Neotropical Heliconius and Laparus butterflies actively collect pollen onto the proboscis and extract nutrients from it. This study investigates the impact of the processing behaviour on the condition of the pollen grains. Pollen samples (n = 72) were collected from proboscides of various Heliconius species and Laparus doris in surrounding habitats of the Tropical Research Station La Gamba (Costa Rica). Examination using a light microscope revealed that pollen loads contained 74.88 ± 53.67% of damaged Psychotria pollen, 72.04 ± 23.4% of damaged Psiguria/Gurania pollen, and 21.35 ± 14.5% of damaged Lantana pollen (numbers represent median ± first quartile). Damaged pollen grains showed deformed contours, inhomogeneous and/or leaking contents, or they were empty. Experiments with Heliconius and Laparus doris from a natural population in Costa Rica demonstrated that 200 min of pollen processing behaviour significantly increased the percentage of damaged pollen of Psychotria compared to pollen from anthers (P = 0.015, Z = −2.44, Mann–Whitney U-test). Examination of pollen loads from green house reared Heliconius butterflies resulted in significantly greater amounts of damaged Psiguria pollen after 200 min of processing behaviour compared to pollen from flowers (P < 0.001, Z = −4.583, Mann–Whitney U-test). These results indicate that pollen processing functions as extra oral digestion whereby pollen grains are ruptured to make the content available for ingestion.

中文翻译：

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花粉的机械损伤有助于 Heliconius 蝴蝶（蛱蝶科）的养分获取。

新热带Heliconius和Laparus蝴蝶主动将花粉收集到长鼻上并从中提取营养。本研究调查了加工行为对花粉粒状况的影响。花粉样本 ( n = 72) 是从热带研究站 La Gamba（哥斯达黎加）周围栖息地的 各种Heliconius物种和Laparus doris的长鼻中采集的。使用光学显微镜检查显示，花粉负载中含有 74.88 ± 53.67% 的受损Psychotria花粉、72.04 ± 23.4% 的受损Psiguria/Gurania花粉和 21.35 ± 14.5% 的受损马缨丹花粉（数字代表中位数±第一四分位数）。受损的花粉粒表现出变形的轮廓、不均匀和/或泄漏的内容，或者它们是空的。来自哥斯达黎加自然种群的Heliconius和Laparus doris的实验表明，与来自花药的花粉相比，200 分钟的花粉处理行为显着增加了Psychotria花粉受损的百分比（ P  = 0.015，Z  = -2.44，Mann-Whitney U -测试）。对温室饲养的Heliconius蝴蝶的花粉负荷进行检查，导致受损的Psiguria数量显着增加处理 200 分钟后的花粉与来自花的花粉相比（P  < 0.001，Z  = -4.583，Mann-Whitney U -test）。这些结果表明，花粉加工起到额外的口腔消化作用，花粉粒破裂以使内容物可用于摄取。