- 學位論文
Behavioral Response to Low Frequency Vibrations in Snake Ants, Leptogenys kitteli (Hymenoptera: Formicidae)
Behavioral Response to Low Frequency Vibrations in Snake Ants, Leptogenys kitteli (Hymenoptera: Formicidae)
摘要
土妻昆蟲時常需要處理來自環境或同種夥的振動訊息，而這些訊息是帶有危急或其它溝通意義。在往昔研究中，這些訊息時常為單一頻率的低頻振動。吉悌細額針蟻﹝Leptogenys kitteli﹞，俗稱蛇蟻,，和那些能夠以振動訊號溝通的螞蟻一樣，具有摩擦行為﹝stridulatory behavior﹞。本研究中，我將驗證兩件事：第一、蛇蟻是否有對特定頻率反應靈敏；第二、這些振動是否可以引起牠們的警戒行為。 在實驗中，我用三種振幅﹝0.05 g、0.1 g、0.2 g﹞和15到1500赫茲的低頻振動刺激蛇蟻，進而觀察牠們的行為反應。當受到刺激後，牠們大部分會開始亂竄，有時甚至會衝往巢外。蛇蟻對於兩個頻帶的振動有相當靈敏的反應：60赫茲和120到135赫茲。後者的反應較前者劇烈，且其頻帶差不多為前者的諧頻。我推測這樣的諧頻關係是來自於螞蟻附肢和地面介質的連結結構。60赫茲的振動傳過附肢時，也一併產生120赫茲的諧頻來刺激感受器。 此外，螞蟻反應達到最大值後，開始迅速衰減。但過了數秒後，此衰減趨勢會緩和下來，並且蟻群會開始頻繁的使用觸角與同伴溝通。我認為牠們的行為表現從獨立個體時期進入群體社會時期。振動的振幅和頻率，決定了個體時期的時間長度。在高振幅和敏感的頻帶，此時期會有較久的持續時間。另外個體時期的時間也和行為反應強度有正相關。隨著刺激引起較低的反應活動，個體時期也逐漸縮段，最後消失。螞蟻的行為表現也將略過個體時期，直接進入社會時期。於此研究中，我確立了120到135赫茲的振動可以引起蛇蟻的警戒行為，但是此頻率振動所以扮演的角色，是天敵入侵的暗示或同伴溝通的訊號，仍須進一步實驗才能確定。
並列摘要
Soil insects process the vibrational messages from environments or conspecific partners for emergencies or communication very often. From the past study, these messages generally are low frequency and pure tone vibration. Snake ants, Leptogenys kitteli, have the same stridulatory behaviors with the ants which are able to communicate in vibrational signals. I would examine two questions: first, is L. kitteli sensitive to a specific frequency; second, whether the ants perform alarm behavior while recepting vibrations? In the experiments, snake ants were stimulated with low frequency vibrations from 15 Hz to 1500 Hz and 3 amplitudes, 0.05 g, 0.1 g, 0.2 g, to examined what responses they had. The general behaviors the snake ants had when given vibrational stimuli were rushing around and out of the nests. They reacted sensitively to two frequency areas, one was about 120 to 135 Hz and the other weaker one was the former fundamental frequency, 60 Hz. I thought it was caused from the connection structure between organism and substrate. When the 60 Hz vibration transmitted to appendages, the connection structure also produced some 120 Hz harmonic frequency to stimulate the receptors. Furthermore, after the maximum activity, the ants subsided quickly at first, but after few seconds, the subsiding trend slowed down. The ants exhibited great interaction with each other by using antennae. I thought they went from independent individual stage into social interaction stage. Amplitude and frequency determined the duration of the individual stage. At high amplitudes and sensitive frequencies, the durations lasted longer. In addition, they also had positive correlation with the magnitude of measurable activities. As the stimulations triggered lower activities of the ants, the durations also decreased, even vanished. Thus, the ants skipped the individual stage into the social stage. The study has established 120 to 135Hz are important signals to snake ants’ alarm behavior. However, which role these frequencies play: predator-closing cue or nestmate-communicating signal, I still need to further work to examine.