Elucidation of the mechanism of host web manipulation by spider-ectoparasitoids based on the molecular mechanism of web-building behavior

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K16235
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: Keio University
• Principal Investigator: TAKASUKA Keizo 慶應義塾大学, 政策・メディア研究科(藤沢), 特任助教 (00726028)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: ナガコガネグモ / ジョロウグモ / 網操作 / 造網行動 / アカクモヒメバチ / マイクロインジェクション

Outline of Final Research Achievements

In order to identify the antagonists of the neuroreceptors involved in spider's web-building behavior, I observed the changes in behavior after injecting bioactive substances, mainly neurotransmitters, into the spider's abdomen, but I was unable to identify the antagonists during the study period due to problems with the efficiency of the injection system. However, several bioactive substances that did not affect the web-building behavior were identified from the negative results.
I also found a spider-ectoparasitoid, Eriostethus rufus, which most probably parasitized a nephiline spider, Trichonephila clavata, supposed by several circumstantial evidences left in the modified web from which the wasp cocoon hung, in Tsuruoka city, Yamagata Prefecture. This is a new host record of the species and even among all spider-ectoparasitoids, and thus the first case of web manipulation against T. clavata.

Free Research Field

昆虫生態学

Academic Significance and Societal Importance of the Research Achievements

網を作るというクモの造網行動はよく知られているものの、その分子機構はほとんどわかっていない。今回造網行動の生理基盤を司る生理活性物質のスクリーニングを目指し、特定には至れなかったものの、造網生理には関与していない複数の物質を明らかにできたほか、クモへのインジェクション実験確立に近づく土台を築けた。これらの基礎的な知見や技術の蓄積は、タンパク質マテリアルになりうるクモ糸の生体内合成メカニズムや造網行動の神経生理の解明に向けた足掛かりとなる。
また、一般にも広く知られるジョロウグモで初めて寄生バチの存在を発見し、その造網行動を操作していることを明らかにしたことは一般社会に対してもインパクトがある。