Abstract：
Blood feeding is a secondary adaptation in hematophagous bugs. Many proteins are secreted in the saliva that are devoted to coping with the host\'s defense and to process the blood meal. Digestive enzymes that are no longer required for a blood meal would be expected to be eventually lost. Yet, in many strictly hematophagous arthropods, α-amylase genes, which encode the enzymes that digest starch from plants, are still present and transcribed, including in the kissing bug Rhodnius prolixus (Hemiptera, Reduviidae) and its related species, which transmit the Chagas disease. We hypothesized that retaining α-amylase could be advantageous if the bugs occasionally consume plant tissues. We first checked that the α-amylase protein of Rhodnius robustus retains normal amylolytic activity. Then we surveyed hundreds of gut DNA extracts from the sylvatic R. robustus to detect traces of plants. We found plant DNA in 8% of the samples, mainly identified as Attalea palm trees, where R. robustus are usually found. We suggest that although of secondary importance in the blood-sucking bugs, α-amylase may be needed during occasional plant feeding and thus has been retained.
摘要：
血液喂养是吸血虫子的二次适应。唾液中分泌许多蛋白质，用于应对宿主的防御和处理血粉。血餐不再需要的消化酶预计最终会丢失。然而，在许多严格的食血节肢动物中，α-淀粉酶基因,编码消化植物淀粉的酶，仍然存在并转录，包括接吻虫Rhodniusprolixus（半翅目，Reduviidae）及其相关物种，传播查加斯病。我们假设，如果虫子偶尔消耗植物组织，保留α-淀粉酶可能是有利的。我们首先检查了罗汉斯的α-淀粉酶蛋白保持正常的淀粉分解活性。然后，我们调查了数百种来自sylvaticR.robustus的肠道DNA提取物，以检测植物的痕迹。我们在8%的样本中发现了植物DNA,主要被确定为Attalea棕榈树，通常发现R.robustus。我们建议，尽管在吸血虫子中次要重要，在偶尔的植物饲喂过程中可能需要α-淀粉酶，因此已被保留。
