親代的打鬥勝敗經驗是否會影響子代對勝敗經驗的反應-以紅樹林鱂魚為例

Abstract

個體為了競爭有限的資源而展現攻擊性。個體的攻擊性可能受到自己的打鬥勝負經驗或其親代經歷的環境所影響。個體近期獲勝／落敗的打鬥經驗提高／降低牠在下次打鬥時的攻擊性，稱之為勝/敗者效應。另外，目前有許多研究發現，親代的經歷影響其子代的行為表現，此現象稱為母體效應。親代可能傳遞環境資訊給其子代，替子代預期環境的狀況，使子代在面對相似的經歷時表現出適當的反應。然而，目前尚未有研究探討個體獲得打鬥經驗後的行為表現是否會受到其親代打鬥經驗的影響。本研究欲檢測個體的行為，即打鬥經驗前的攻擊性與經驗後的攻擊性，是否受到其親代之打鬥經驗影響。本研究同時也檢測個體之生理生活史特徵（孵化所需時間、生長速率、性成熟年紀）和（皮質醇、睪固酮濃度）是否為親代打鬥經驗影響個體行為的可能機制。本研究使用紅樹林鱂魚作為實驗物種進行研究。實驗使用3  3的二因子實驗設計，包含親代三種經驗（獲勝／落敗／控制經驗）處理，和個體本身三種經驗（獲勝／落敗／控制經驗）處理。首先強制給予親代個體指定的打鬥經驗（獲勝／落敗／控制經驗）後收集其子代為子代實驗的目標個體，並觀察子代個體的生活史特徵。子代長至8月齡大時，始給予打鬥經驗，並觀察個體之行為及生理特徵。本研究結果顯示(1)有過落敗經驗之親代所產下之子代具有較高的攻擊性；(2)個體經驗後之攻擊性受子代打鬥經驗的影響，並不受其親代之打鬥經驗影響；(3)個體的生理、生活史特徵幾乎不受親代打鬥經驗的影響，有過打鬥經驗之親代所產下之子代有較快的生長速率；(4)個體的攻擊性的表現與個體的生活史和生理特徵間無相關。總結上述結果，在行為方面，個體攻擊性會受親代打鬥經驗的影響，但個體對打鬥經驗的反應主要是受到自己打鬥經驗的影響；於生活史特徵方面，個體生長速率雖然受其親代的打鬥經驗影響，但與自身攻擊性表現無關。本研究結果證實了親代的打鬥經驗會傳遞給子代環境中的資訊，並增加子代在獲得任何打鬥經驗前的競爭能力。然而，當子代親身經歷過打鬥經驗後，親代的打鬥經驗就不會再影響子代的攻擊性，顯示只有自身經歷過的打鬥經驗才能提供自身打鬥能力相關資訊。Animals show aggressiveness for limited resources. Animals aggressiveness is probably influenced by their contest experiences or their parent’s environmental experiences. Individuals with a recent winning/losing experience would behave more/less aggressively in the next contest (winner effect/loser effect). In addition, recent researches have revealed that individuals’ phenotype can be influenced by their parents’ environmental experiences (maternal effect). Individuals’ fitness can be increased by behaving appropriately in specific conditions based on environmental informations from their parents. However, there has been no research investigating whether individuals’ responses to their own contest experiences is affected by fighting experiences of their parents. The purposes of this study were whether parents’ fighting experiences can influence individuals’ pre- and post-experience aggressiveness; and whether parents’ fighting experience can also influence individuals’ life-history and physiological traits. The mangrove killifish Kryptolebias marmoratus was used in the 3  3 factorial design: the experimental fish that were offspring from parents with three different fighting experiences (winning/losing/no experiences), were randomly assigned to three different fighting experiences (winning/losing/no experiences). The parents’ eggs were collected after fighting experiences treatments. The first offspring with normally health condition of the parent was the test fish inthis study. The test individuals were recorded their life-history traits. When the test fish were 8 months old, I observed their aggressiveness and physiological traits. Then I gave them fighting experiences and observed their post-experience aggressiveness. The results showed that: (1) theindividuals’ pre-experience aggressiveness was influenced by parents fighting experiences, especially individuals with parents’ losing experiences had higher levels of aggressiveness; (2)the individuals’ aggressiveness after their own fighting experiences was not influenced by parents’ fighting experiences; (3) theindividuals’ growth rate was influenced by parents’ fighting experiences, especially individuals with parents’ losing experiences grew faster; (4) theindividuals’ aggressiveness did not correlate with their own life-history, and physiological traits. Overall, the individuals’ aggressiveness was influenced by parents’ fighting experiences. However, there was no effect from parents’ fighting experiences on individuals’ aggressiveness when individuals had their own fighting experiences. The individuals’ growth rate was influenced by their parents’ fighting experiences. But, there was no relationship between individuals’ aggressiveness and growth rate. These results suggest that parent would transmit the information of parents’ fighting experiences and increase offspring’s competitive ability; however, there was no effect from parents’ fighting experiences on individuals’ aggressiveness when the fish has their own fighting experiences.