Nodai Entomology (4): 1-3 (2023)© Nodai Entomological Laboratory

An Occasional Journal of the Nodai Ent. Lab.

N ODAI E NTOMOLOGYISSN 2435-3965 (Online)

https://www.nodai.ac.jp/agri/original/konken/shigen/publication/publication.html

Alternative host plants for adults of Euphyllobiomorphus kurosawai Morimoto(Coleoptera, Curculionidae, Entiminae), endemic to Yakushima Island, off ofsouthern Kyushu, Japan
Hiroaki KOJIMA 1) & Takeshi YÔRO 2)
1) Laboratory of Entomology, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa, 243-0034 JapanE-mail: h3kojima@nodai.ac.jp2) 4-21-11 Ougigayatsu, Kamakura, Kanagawa, 248–0011 Japan

Abstract Two coniferous trees, Tsuga sieboldii and Abies firma, both belonging to the family Pinaceae,
are recorded for the first time as alternative host plants for adults of Euphyllobiomorphus kurosawai
Morimoto, 1962 in addition to the previously known hosts of Cryptomeria japonica and Juniperus chinensis
var. sargentii of the family Cupressaceae.
Host and refuge/alternative plants of weevils were listed by Colonnelli & Osella (1998) for thefirst time. These latter plants were used by the species, mainly by adults, as feeding resources when theusual hosts were not available and are unusual weevil-plant associations.
An entimine weevil, Euphyllobiomorphus kurosawai Morimoto, 1962 is one of the mostrepresentative insect species on Yakushima Island, which is a World Natural Heritage site in Japan,
since the species is not only endemic to the island but also is a sole representative of the monotypic
genus. The weevil is very unique with an exceptionally long, cylindrical rostrum as in the long-nosed
weevils (Phanelognatha) in the broad-nosed weevil subfamily Entiminae, and is currently thesouthernmost representative of the tribe Phyllonini in Japan (Morimoto & Kojima, 1994; Morimoto etal., 2006). This species has been known to feed on Japanese cedar, Cryptomeria japonica (Sugi in Japanese ;Cupressaceae) (Morimoto et al., 2006). Recently, we reported the association of this weevil with anotherconifer, Sargent’s juniper, Juniperus chinensis var. sargentii (Miyamabyakushin in Japanese;
Cupressaceae) (Kojima & Yôro, 2019). During a recent trekking of Yakushima's mountains in July, thesenior author found many individuals of this species by hand shaking of such coniferous tree branches
as the Japanese hemlock, Tsuga sieboldii and the Japanese fir, Abies firma (Pinaceae; Tsuga and Momi inJapanese, respectively) near the Ishizuka-goya hut, ca. 1km east of Hananoego of the highland marsh.
These trees stood next to a Japanese cedar, from which a few adults were found in addition to ones fromthe Japanese hemlock and fir. The following record was based on senior author's field observation andadult weevils were released without capturing. Nearly 10 adults fell on a circular beating tray (60cm indiameter) from the Japanese hemlock and fir stands by shaking a few of the lower branches, about
170~200cm from ground level. Only a few adults fell from the adjacent Japanese cedar despite repeated
hand shaking of the branches. Adults of this weevil emerged from March to May in lowland planted
forests, and from May or June to July in mountainous areas according to personal collecting data fromthe Kyushu University Museum (Kojima, unpublished data). These data suggest that the adultoccurrence at this time (July 15th) was of a late stage emergence for this species. During that time, otherconiferous tress such as the Japanese hemlock and fir might be utilized by adults as alternative or refuge
plants in place of the usual/primary host, the Japanese cedar.
In addition to the Sargent’s juniper, we herein add for the first time the Japanese hemlock and fir
Accepted 24 Sep 2023; published 2 Dec 2023
Licensed under a Creative Commons Attribution License CCBY 4.0

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Nodai Entomology, (4): 1-3Figs. 1-3. Habitat of Euphyllobiomorphus kurosawai near Ishizuka-goya hut (ca. 1,600m inaltitude). 1, Vegetation (a: Cryptomeria japonica; b: Abies firma; c: Tsuga sieboldii); 2, Tsuga
sieboldii (triangular mark shows collecting site); 3, Abies firma (triangular mark shows
collecting site).
as alternative adult hosts of Euphyllobiomorphus kurosawai. The occurrences of these coniferous trees,
including the Japanese cedar, on Yakushima Island representing the southernmost distributional
records and correspond with the occurrence of a Euphyllobiomorphus weevil, representing thesouthernmost species of the tribe Phyllobini in Japan. Also, it has become apparent that the weevil
utilizes not only the plant family Cupressaceae but also the Pinaceae.

Kojima & Yôro (2023) — Alternative Adult Host Plants of Euphyllobiomorphus kurosawai

3Acknowledgments. The authors thank Mr. Hiroshi Onodera, the chairman of the Yakushima
Environmental and Cultural Foundation for his constant encouragements. The senior author also
thanks Mrs. Mitsuko Hidaka of Shisuikan Guest House, Mrs. Yasuko Iwakawa, Suimeisô Guest House,
all the staff of the Riverside Bar St. Pote, Anbô, for their kind care and support during his stay, and Mr.
Sukenobu Konishi of Nagamine for his kind field guidance. The senior author also thanks Dr. Steven R.
Davis of Nodai Entomology, Atsugi for his critical reading the manuscript.
This study was partially supported by the Grant-in-Aid for Biodiversity Research of theYakushima Environmental and Cultural Foundation (Chairman: Mr. H. Onodera).

要 約
⼩島弘昭・養⽼孟司：屋久島固有のアオクチナガヒゲボソゾウムシ（甲⾍⽬ゾウムシ科）成⾍の新代替加害植物．̶̶̶̶これまでアオクチナガヒゲボソゾウムシの成⾍加害植物としてスギが知られていたが，島の⾼地（⼭地）では同じヒノキ科のビャクシンを利⽤することが最近明らかになった．今回，新たに島の⾼地においてマツ科に属するツガとモミから本種成⾍をまとまった数確認したので，新加害植物として報告した．なお，これら針葉樹に隣接してスギが⾒られたが，ツガやモミに⽐べ明らかに確認された成⾍個体数が少なかった．本種成⾍の⾼地での採集記録は５，６⽉から７⽉で，今回成⾍が確認された 7 ⽉中旬は本種成⾍の出現期後期と考えられ，ツガ，モミはスギの代替植物として利⽤している可能性がある．また，本種成⾍がヒノキ科のみならずマツ科も利⽤していることが初めて明らかとなった．
References
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Kojima, H. & T. Yôro, 2019. A new plant host record for adult of Euphyllobiomorphus kurosawai Morimoto(Coleoptera, Curculionidae, Entiminae), endemic to Yakushima Island, Kyushu, Japan. Nodai
Entomology, Atsugi, (1): 1-2.
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