First record of drinking behavior mediated by proboscis in an adult female of Brahmaea japonica, suggesting reconsideration of the conventional morphological interpretation

・概要 / Abstract

イボタガ(Brahmaea japonica)成虫の口吻は短く機能しないと考えられ、「非摂食」と一般的に認識されてきた。しかし、この認識は主に形態学的観察に基づく推定であり、行動学的証拠は乏しい。

縮退した口吻を持つ鱗翅目でも、水分摂取が確認されている種(例:Gluphisia septentrionis)がある。一方で本種については同様の報告が見られない。

本論では、同種成虫♀の産卵直後に吸水行為の発現を動画により記録・確認したため、従来認識の再検討を試みた。

The proboscis of adult Brahmaea japonica has traditionally been regarded as vestigial or non-functional, consequently, this species has generally been thought to be incapable of feeding. However, this consensus relies on morphological inferences, while direct ethological evidence remains insufficient.

Although drinking behavior has been documented in other related taxa possessing rudimentary proboscis (e.g., Gluphisia septentrionis), no such observations have been reported for Brahmaea japonica.

Here, I report the first recorded observation of drinking behavior in an adult female of Brahmaea japonica, occurring immediately after egg-laying. This behavioral evidence was captured via video documentation.

These findings may warrant a re-evaluation of the conventional understanding of the functional role of proboscis.

・キーワード / Key words
イボタガ、口吻、吸水、摂食、摂取、初記録
Brahmaea japonica, Brahamaeidae, proboscis, drinking behavior, feeding behavior, first record

*Correspondence : Shinjiro Hayashi / Email: sh.4.research●gmail.com (replace ● with @)