益達胺對黑棘蟻的亞致死效應

Sublethal effects of imidacloprid on the gray-black spiny ant, Polyrhachis dives

戴允文(Yun-Wen Dai)

指導教授 ： 楊恩誠

共同指導教授 ： 楊景程(Chin-Chen Yang)

國立臺灣大學/生物資源暨農學院/昆蟲學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201610136

摘要

使用殺蟲劑的主要目的為消滅害蟲，但可能會造成其他非標的生物的影響，如授粉者 (蜜蜂) 或其他捕食性昆蟲。益達胺為目前廣泛使用之系統性殺蟲劑，作用於昆蟲的尼古丁型之乙醯膽鹼受器 (nicotinic acetylcholine receptor, nAChR)，導致神經興奮過度 (hyperpolarization) 而麻痺死亡。研究顯示益達胺的亞致死效應對昆蟲生理與行為會造成影響，其中以造成外勤蜂不正常的覓食行為最為顯著。但同為社會性昆蟲之螞蟻卻幾乎無此類研究。螞蟻於覓食過程中，可能會直接接觸環境中殘留之藥劑或取食遭受藥劑污染的昆蟲或物質，使毒性累積於螞蟻體內；並可能藉由交哺作用 (trophallaxis) 傳遞給幼蟲，進而導致蟻巢衰弱。本研究選用黑棘蟻 (Polyrhachis dives) 作為研究材料，首先建立黑棘蟻的毒性資料，藉給予黑棘蟻亞致死濃度 LC1 及 致死濃度 LC15 及 LC50 的益達胺，檢測覓食行為、行為反應及個體與群體種間競爭的結果是否受到影響。結果顯示益達胺降低黑棘蟻對食物分子的反應並影響覓食趨勢。覓食時間 (foraging time) 皆無顯著差異，但在致死濃度 (LC15 及 LC50) 下標準差幅度變大，推測益達胺影響黑棘蟻腦中的感知系統，導致對外界刺激反應降低。在個體種間競爭部分，無論遭遇 major 或 minor 火蟻，致死濃度(LC15 及 LC50) 的接觸使黑棘蟻侵略行為明顯下降，亞致死劑量則無顯著差異，個體競爭死亡率亦無顯著差異。在群體種間競爭部分，致死濃度的施用造成火蟻存活率上升，亞致死濃度則無顯著差異。此結果支持益達胺的施用會改變螞蟻的行為及改變種間競爭的結果，推測益達胺可能影響螞蟻的感知系統或腦中處理行為的區域，進而造成黑棘蟻行為改變。

關鍵字

覓食活動 ； 種間競爭 ； 新類尼古丁藥劑 ； 黑棘蟻 ； 亞致死效應 ； 入侵紅火蟻

並列摘要

The purpose of applying insecticide is to control pest, but it may affect other non-target individual, like pollinators or predators. Neonicotinoids, such as imidacloprid, is a systematic insecticide widely used around the world. It acts on nicotinic acetycholine receptor (nAChR) inducing hyperpolarization and death. Previous studies indicated sublethal effect of imidacloprid could affect behavior of insects. Only few concerned about ant, as one of the important social insects. Ant may contact the residue of insecticide or intake prey killed by insecticide to aggregate insecticide inside the body and pass to the larva through trophallaxis, thus inducing colony collapse eventually. We built oral toxicity data of imidacloprid and tested whether imidacloprid contamination could affect foraging, behavioral reactions and interactions between a native ant Polyrhachis dives and an invasive ant Solenopsis invicta with sublethal (LC1) and lethal concentrations (LC15 and LC50). The results showed that imidacloprid contamination reduces the reactions of P. dives to food signal and affects foraging patterns. The food discovery time was not affected, but dynamic in the lethal concentrations, suggesting that imidacloprid might affect cognitive system in brain and consequently hampers the reactions to stimulus. During interspecific competition at individual level, exposed individuals displayed reduced aggression at lethal concentrations, but not at sublethal concentrations. The mortality of interspecific competition was not affected. During interspecific competition at small colony fragment level, survivorship of fire ants increase in lethal concentrations, but was no significantly affected at sublethal ones. These results suggest that that the exposure of neonicotinoid could affect behaviors of ants and the interspecific interaction outcomes among different species.

並列關鍵字

foraging behavior ； interspecific competition ； neonicotinoid ； Polyrhachis dives ； Solenopsis invicta ； sublethal effect

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