種間競爭壓力促進尼泊爾埋葬蟲合作行為的地區性適應

Abstract

地區性適應使生物能夠在在不同的環境條件下生存及繁衍，其牽涉演化及生態多種力量的交互作用，並影響生物型態、生活史、行為等各種層面的適應結果。而在行為生態方面，合作行為的演化更被認為是生物於變動的環境下，例如物理條件、生物作用等環境壓力的影響，所衍生的適應策略。然而，儘管知道環境壓力會影響社會行為，但其如何對於不同族群的合作行為產生地區性的適應分化，仍舊缺乏較完整的討論。對此本研究以分布於臺灣陽明山和合歡山兩個地區的尼泊爾埋葬蟲（Nicrophorus nepalensis）族群做為研究對象，探討其族群之間合作行為的地區性適應是受到哪些環境因素所驅使。研究透過野外調查和共園合作行為實驗，探討溫度和麗蠅競爭是否影響不同地區尼泊爾埋葬蟲的分布及合作行為的差異。調查結果顯示，在族群分布上，不同於全年分布的合歡山族群，陽明山地區的尼泊爾埋葬蟲只在特定的季節活動，並且在分布上與麗蠅發生種間競爭的程度也較低。此外，共園實驗結果也顯示，合歡山族群在面臨麗蠅競爭時，表現出比陽明山族群更合作的群體繁殖。研究表明麗蠅壓力的不同，造就地區之間的尼泊爾埋葬蟲族群在面對種間競爭的合作行為表現產生歧異。本研究揭示種間競爭影響了社會行為產生地區性適應的具體案例，並為生物之間的交互作用如何影響物種分化提供了新的見解。Local adaptation allows organisms to survive and reproduce under various environmental conditions, involving the interplay of evolutionary and ecological forces that affect various aspects of adaptation, including morphology, life history, and behavior. In behavioral ecology, the evolution of cooperative behavior is considered an adaptive strategy derived from environmental pressures, such as physical conditions and biological interactions. However, despite understanding that environmental pressures influence social behavior, the discussion on how these pressures lead to local adaptation differentiation in cooperative behaviors among different populations remains incomplete. This study focuses on the populations of burying beetles Nicrophorus nepalensis found in Mt. Yangming and Mt. Hehuan in Taiwan to investigate the environmental factors driving the local adaptation of cooperative behaviors between these populations. Through field surveys and common garden experiments on cooperative behavior, this study explores whether temperature and blowfly competition affect the distribution and differences in cooperative behavior of N. nepalensis in different regions. The results show that, unlike the year-round population in Mt. Hehuan, the Mt. Yangming population of N. nepalensis is active only in specific seasons and has a lower degree of interspecific competition with blowflies. Furthermore, the common garden experiments revealed that the Mt. Hehuan population exhibits more cooperative group reproduction in the face of blowfly competition than the Mt. Yangming population. This study demonstrates that different pressures from blowflies lead to divergent cooperative behavior in facing interspecific competition between N. nepalensis populations in different regions. It provides a concrete case of how interspecific competition affects social behavior leading to local adaptation and offers new insights into how interactions between organisms influence species differentiation.