小紅姬緣椿象之吸食提高其寄主植物倒地鈴種子發芽率

Enhancement Effect of the Feeding of Leptocoris Augur on the Germination Rate of Its Host Plant Cardiospermum Halicacabum

小紅姬緣樁象（Leptocoris augur Fabricius）具有特殊吸食口器，可突破倒地鈴（Cardiospermum halicacabum L.）的種子防衛。倒地鈴種子經小紅姬緣樁象吸食後，發芽率於14~42天間，可提高3.2~6.0倍（與對照組相比）。模擬野外小紅姬緣樁象的吸食實驗，含果莢種子餵養兩週後，種子發芽率於28~42天間，則可提高2.6~9.0倍。倒地鈴種子經吸食過後，發芽率提升的機制，類似對種皮的物理傷口，如縫衣針或指甲剪處理，透過種皮傷口增加種子的吸水量。種子被吸食過，不僅沒有死亡，且可促進發芽率。野外觀察近八成（78.2%）的種子只被刺吸一針或兩針，且刺吸的位置未傷及胚。小紅姬緣樁象與其寄主植物倒地鈴，顯現有互利共生的關係。

Leptocoris augur Fabricius feeds on seeds of the heartseed vine (Cardiospermum halicacabum L.), using its unique mouthparts that are capable of piercing through the pod and seed coat. Germination rates of the seeds fed by L. azrgus were found to be 3.2 and 6.0 times higher than those of the unfed ones on 14 and 42 days after feeding, respectively. We also conducted a simulation experiment, in which heartseed vine seeds were fed by L. argus for two weeks. The germination rates of the seeds fed were 2.6 and 9.0 times higher than those of the unfed ones on 28 and 42 days after feeding, respectively. The underlying mechanism associated with the enhancement of the feeding on the germination were similar to that resulted from physical wounds by needle or nail clippers. The wounds improved water absorption of the seeds that in turn enhanced the germination rate. In our field observation, approximately eight out of the (78.2 %) seeds were pierced once or twice by L. argus. The wounds did neither kill the seeds nor injure the embryos but enhanced the germination rate. Apparently, there is a mutualism relationship between L. augur and its hot C. halicacabum.