Edaphologia

Effects of high temperature and drought conditions on four Megascolecidae earthworms dominant in agricultural fields in Japan

Satoshi Kaneda

2023 Volume 112 Pages 1-8
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_1

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Because earthworms are vulnerable to high temperatures and dry conditions, their response to high temperatures is useful for understanding the seasonal dynamics of earthworm densities and environmental change impacts induced by agricultural activity on earthworms. However, there is little information on the high temperature tolerance of the Megascolecidae species. The family is dominant in Asia, with some species becoming invasive in other continents, where they may cause problems by changing ecosystem structure. This study's objective was to determine the high temperature tolerance of four Megascolecidae species (Metaphire hilgendorfi, M. agrestis, Amynthas corticis, and A. micronarius). Two experiments were conducted. In the first experiment, incubation temperatures were set to five levels (15, 20, 25, 30, and 35°C) under soilless conditions. The 50% lethal temperature was determined after 2 days of incubation; the lethal temperatures for M. hilgendorfi, M. agrestis, A. corticis, and A. micronarius were 22.5, 21.3, 31.9, and 25.5°C, respectively. In the second experiment, four moisture levels, 30, 40, 50, and 60% of water holding capacity (WHC), were set, and the temperature increased weekly from 15 to 35˚C. Survival rate and weight were measured weekly. Metaphire agrestis was removed from the analysis because the culture conditions of the experiment were not suitable for this species. At the lowest moisture condition (WHC30%), almost all individuals died, within one week. Dry conditions thus have a severe effect on earthworms. The 50% lethal temperature increased with increasing moisture level, with drastic weight loss occurring just before onset of the lethal temperature. Tolerance to higher temperature of epigeic species was lower than that of endogeic species.

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Descriptions of two new species of the genus Amynthas (Annelida: Oligochaeta: Megascolecidae) and a new record of Amynthas righii Hong & James, 2001 from Kanagawa Prefecture, Central Japan

Masamichi Ito, Hiroyuki Sakai, Atsushi Tamura

2023 Volume 112 Pages 9-16
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_9

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For the first time, two new species of the genus Amynthas were discovered in the western mountain range of Kanagawa Prefecture, Central Japan and described herein. These new species, namely A. quadriverrucifer sp. nov. and A. suinaris sp. nov., are distinguished from their congeners by having genital markings, i.e., two pairs of distinct papillae are present on an asymmetric spindle-shaped glandular pad of segment 8, and characteristic male pores resembling the snout of a pig, respectively. In addition, Amynthas righii Hong & James, 2001, previously found in Korea, was recorded in Japan for the first time and is also described herein.

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Redescription of the generic type species Crossodonthina nipponica (Collembola: Neanuridae)

Atsuko Ohira, Taizo Nakamori

2023 Volume 112 Pages 17-24
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_17

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The identity of the generic type species Crossodonthina nipponica Yosii, 1954 is unclear because the original description lacks detail and the redescriptions from different localities are inconsistent. In this study, C. nipponica was redescribed based on specimens collected in the type locality. Also, partial regions of the mitochondrial cytochrome c oxidase subunit 1 of C. nipponica were also sequenced for DNA barcoding.

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A unique oviposition behavior and oothecal morphology in Anaplectella ruficollis (Karny, 1915) (Blattodea: Blattellidae)

Shizuma Yanagisawa, Kotaro Okazaki, Shotaro Ohgita

2023 Volume 112 Pages 25-29
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_25

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The oviposition of eight individuals of Anaplectella ruficollis (Karny, 1915), one at a time, was observed in 170 ml clean cups set at room temperature (22–27ºC) and under fluorescent light. Anaplectella ruficollis produces pale brown ootheca which are rotated clockwise. 15–35 minutes, the ootheca has rotated 90º. The ootheca is then retracted into the abdomen for 58–72 minutes. After 2–11 days, the brown-colored ootheca is laid and covered with the substrate. The oviposition behavior of Anaplectella ruficollis observed in this study is unique once the ootheca is retracted into the abdomen. Although it is thought to be closely related to ovoviviparity, it is still appropriate to classify it as oviparous A. This was because the ootheca had a rigid oothecal membrane and serrated keel, and the females dropped the ootheca well before the hatch. Additionally, form of ootheca was asymmetrical from left to right and bordered by the suture line, which suggests an advantage to the traits for retraction into the abdomen.

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First report of the snail mite Riccardoella triodopsis (Acari: Ereynetidae) from Mainland China

Tsukasa Waki, Takahiro Hirano, Bin Ye, Satoshi Shimano

2023 Volume 112 Pages 31-34
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_31

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The snail mite Riccardoella triodopsis Fain & Klompen, 1990 was found on the land snail Aegista brevibarbis (Pfeiffer, 1859) in Zhejiang Province, China. The mite specimens were identified based on morphological characters, mainly the chaetotaxy of the palptarsus and leg, and structure of the famulus and its guard seta on tibia I. This study is the first report of the genus Riccardoella Berlese, 1923 and the snail mite R. triodopsis from Mainland China.

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Predation by a geophilomorph centipede Strigamia bicolor (Chilopoda: Linotaeniidae) on a land snail Trochochlamys crenulata (Gastropoda: Euconulidae)

Taro Jonishi, Naoto Sawada, Takafumi Nakano

2023 Volume 112 Pages 35-36
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_35

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Current status of scientific names and Japanese names (including proposed new Japanese names) of the order Schizomida (Arachnida) in Japan

Satoshi Shimano, Takeshi Sasaki

2023 Volume 112 Pages 37-38
Published: January 05, 2023
Released on J-STAGE: January 05, 2024

DOIhttps://doi.org/10.20695/edaphologia.112.0_37

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