Overwintering States of the Pale Grass Blue Butterfly Zizeeria maha (Lepidoptera: Lycaenidae) at the Time of the Fukushima Nuclear Accident in March 2011

Abstract

The Fukushima nuclear accident in March 2011 caused the massive release of anthropogenic radioactive materials from the Fukushima Dai-ichi Nuclear Power Plant to its surrounding environment. Its biological effects have been studied using the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae), but the overwintering states of this butterfly remain elusive. Here, we conducted a series of field surveys in March 2018, March 2019, and April 2019 in Fukushima and its vicinity to clarify the overwintering states of this butterfly at the time of the Fukushima nuclear accident. We discovered overwintering individuals in situ associated with the host plant Oxalis corniculata under natural straw mulch as first-instar to fourth-instar larvae in March 2018 and 2019. No other developmental stages were found. The body length and width were reasonably correlated with the accumulated temperature. On the basis of a linear regression equation between body size and accumulated temperature, together with other data, we deduced that the pale grass blue butterfly occurred as fourth-instar larvae in Fukushima and its vicinity at the time of the accident. This study paves the way for subsequent dosimetric analyses that determine the radiation doses absorbed by the butterfly after the accident.

Metabolomic Response of the Creeping Wood Sorrel Oxalis corniculata to Low-Dose Radiation Exposure from Fukushima’s Contaminated Soil

“…The biological impacts of the Fukushima nuclear accident have been studied in contaminated fields, which have focused on many organisms, including birds such as the barn swallow and goshawk [ 5 , 6 , 7 ], Japanese monkeys [ 8 , 9 , 10 ], intertidal invertebrates [ 11 ], gall-forming aphids [ 12 , 13 ], and plants [ 14 , 15 , 16 , 17 , 18 ]. However, to the best of our knowledge, the most intensively studied species in both field and laboratory experiments is the pale grass blue butterfly Zizeeria maha [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. This small butterfly is popular in Japan (except for in Hokkaido) and has been established as an excellent field indicator species for environmental assessments and evolutionary studies [ 39 , 40 , 41 ] and as an excellent model organism in the laboratory for developmental and physiological studies [ 42 , 43 , 44 , 45 ].…”

Nutrient Imbalance of the Host Plant for Larvae of the Pale Grass Blue Butterfly May Mediate the Field Effect of Low-Dose Radiation Exposure in Fukushima: Dose-Dependent Changes in the Sodium Content

“…Among insects, the pale grass blue butterfly Zizeeria maha (Lepidoptera, Lycaenidae) is an important organism that has been studied since immediately after the Fukushima nuclear accident [ 38 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. This butterfly has many advantages both as a sampling animal for field work and as a laboratory animal [ 77 ].…”

Bionomics of Freyeria trochylus (Freyer, 1844) and Zizeeria karsandra (Moore, 1865) (Lepidoptera, Lycaenidae) on Rodos Island, Greece

“…Early stages of Zizeeria karsandra were measured by taking the length across the body of larvae, as well as the length and width (at its broadest point) of the pupa, using a digital calliper (TOTAL TMT321501). In making measurements between instars we referred to the works of Sakauchi et al (2019) and Venkata Ramana et al (2014). We were able to track the different larval stages by measuring larval frass particles in accordance with Bean (1959) and Southwood and Henderson (2000).…”