尼泊爾埋葬蟲繁殖策略的地區適應演化

Local adaptation of reproductive timing in burying beetles (Nicrophorus nepalensis Hope 1831)

蔡祥瑜(Hsiang-Yu Tsai)

指導教授 ： 沈聖峰

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702803

摘要

長久以來科學家試圖解開生物適應各種環境的成因，隨著氣候變遷日趨劇烈，了解環境差異對於動植物、人類的影響變得更加重要。生物與環境交互作用機制主要分為兩個假說：族群間物種演化出不同表現型的地區適應假說(local adaptation)以及物種可以隨著環境改變彈性調整表現的表現型可塑性假說(behavioral plasticity)，然而過去研究多偏重植物或大尺度地理範圍的族群為主。在本研究中，我們以遍佈亞洲山區的尼泊爾埋葬蟲（Nicrophorus nepalensis Hope1831）為研究對象，結合野外與室內實驗探討影響物種繁殖表現季節變化的因子與機制，我們發現中部地區（中橫）和北部地區（烏來）演化出對光週期不同的繁殖策略和性成熟發育，符合地區適應假說：烏來地區的埋葬蟲在短日照下相較於長日照有較高比例的埋屍體行為以及繁殖成功率，性成熟比例亦為短日照處理高於長日照處理; 中橫地區的埋葬蟲則是在長短日照下皆可以達到性成熟，繁殖成功率也相近。我們更進一步根據環境溫度預測其他地區（奄美、拉拉山）埋葬蟲的繁殖策略，並透過室內實驗證實該兩族群也是透過光週期作為繁殖行為的分化依據。本研究不僅讓我們了解生物分佈上差異的機制，研究結果亦代表著這類型的物種在面對劇烈變動的氣候變動時無法調整表現型而不利生存，恐有滅絕的危機。

關鍵字

地區適應化 ； 埋葬蟲 ； 光週期 ； 性成熟 ； 互換實驗

並列摘要

Predicting how species respond to the rapid climates change becomes an urgent task nowadays. Hypothesis for the interaction between species and environments include “local adaptation” in which species have evolved geographically to differentiation and “behavioral plasticity” in which species can adjust their reaction to environment flexibly. However, it is still unclear how environment influences variation in behavior, especially two populations in short distance. Here, we show that burying beetles (Nicrophorus nepalensis Hope 1831) in two different habitats (Mt. Hehuan and Mt. Wulai) in Taiwan have already reached local adaptation by conducting field experiments, reciprocal transplant, breeding experiments under laboratory condition and physiological dissection. In Wulai population, beetles’ sexual maturity and breeding ratio are higher under short photoperiod than under long one; whereas in Hehuan population, they can breed and become sexual mature with similar ratios between long and short photoperiod. We applied our prediction to two other populations (Mt. Lala and Amami isalnd) and proved that those populations’ breeding strategies are also determined by photoperiod. Our results demonstrate how burying beetles’ reproductive strategies have evolved differentially to photoperiod. Studying the mechanism of species’ response to environment factor will help us not only to understand the distribution of biodiversity, but also to predict how climate change may influence evolution of species.

並列關鍵字

Local adaptation ； burying beetles ； photoperiod ； sexual matured ； reciprocal transplant

參考文獻

黃文伯、葛兆年; “台灣福山地區三種埋葬蟲的分佈與尼泊爾埋葬蟲(Coleoptera: Silphidae) 的族群動態”;生物學報（2013） 48 1-11

藍美琪. “尼泊爾埋葬蟲（Nicrophorus nepalensis）（Coleoptera: Silphidae）野外個體活動時間、空間分布及親代對子代調節與親疏辨認之研究”; 國立台南大學環境生態研究所(2010).

A. Lenga , I. Glitho, J. Huignard; “Interactions between photoperiod, relative humidity and host-plant cues on the reproductive diapause termination in Bruchidius atrolineatus Pic (Coleoptera Bruchidae)”; Invertebrate Reproduction and Developmetn,24:2

Blanckenhorn, W.U. ;“Altitudinal differentiation in the diapause response of two species of dungflies”.EcologicalEntomology(1998),23,1±8.

Charmantier A, Garant D ; “Environmental quality and evolutionary potential: lessons from wild populations”. Proceedings of the Royal Society B: Biological Sciences(2005), 272, 1415–1425.