果実を食べるトカゲが森を育む~マダガスカルの熱帯乾燥林におけるトカゲ3種の果実食の実態を解明~

ad

2025-06-10 京都大学

京都大学のチームは、マダガスカル北西部の熱帯乾燥林において、果実を食べる3種のトカゲ(うちカメレオン含む)が、20種以上の植物の果実を摂食する実態と、その排泄された種子が発芽可能であることを明らかにしました。従来、種子散布の担い手として鳥類や哺乳類が注目されてきましたが、爬虫類であるトカゲにも同様の役割があることが示され、森林再生への寄与が浮き彫りになりました。調査では高温下や夜間も含む過酷な環境で数百匹のトカゲを観察し、発芽実験によって排泄後の種子のバイアビリティが確認されました。これにより、トカゲの果実食と種子散布の重要性が再評価され、森林更新への新たな視点が提供されました。成果は国際誌「Biotropica」に2025年5月29日掲載されました。

果実を食べるトカゲが森を育む~マダガスカルの熱帯乾燥林におけるトカゲ3種の果実食の実態を解明~

モモタマナ属の1種(Terminalia boivinii)の果実を食べるウスタレカメレオン(Furcifer oustaleti)

<関連情報>

マダガスカルにおける3種のトカゲのFrugivory:種子散布者としての生態学的役割への示唆 Frugivory by Three Species of Lizards in Madagascar: Implication for Their Ecological Roles as Seed Dispersers

Ryobu Fukuyama, Wataru Noyori, Shuichiro Tagane, Shouta Iyoda, Hiroki Sato
Biotropica  Published: 29 May 2025
DOI:https://doi.org/10.1111/btp.70052

ABSTRACT

Animal-mediated seed dispersal, particularly endozoochory, is an important ecological process for numerous plant species. Although most research on endozoochory has focused on birds and mammals, some lizards are also known to consume fruits and play a significant role in seed dispersal. However, lizards remain overlooked as frugivores and seed dispersers. To clarify the role of lizards as seed dispersers in forest ecosystems, we conducted behavioral observations and fecal analyses on three diurnal lizard species: Furcifer oustaleti, Oplurus cuvieri, and Zonosaurus laticaudatus in a tropical dry forest in Ankarafantsika National Park, northwestern Madagascar during the wet seasons from 2022 to 2024 (2 years). We also conducted germination trials on seeds defecated by F. oustaleti and O. cuvieri. We captured 89, 254, and 38 individuals of the three lizard species, and 24.7 %, 20.1 %, and 15.8 % of the individuals had seeds in their feces, respectively. Behavioral observations and fecal analyses revealed that F. oustaleti, O. cuvieri, and Z. laticaudatus consumed fruits from 8, 18, and 8 plant species, respectively. For individuals with seeds in their feces, the mean number of defecated seeds per individual was 27.2 (range: 1–300), and we confirmed that some of these species had substantial germination rates (> 50%). Moreover, lizards tended to consume different plant species compared to the Common Brown Lemur (Eulemur fulvus), a principal seed disperser in this forest. These lizards may therefore play important roles as seed dispersers, and their contribution to forest regeneration in Madagascar should be considered.

生物工学一般
ad
ad
Follow
ad
タイトルとURLをコピーしました