Developmental and hemocytological effects of ingesting Fukushima’s radiocesium on the cabbage white butterfly Pieris rapae

Abstract

High morphological abnormality and mortality rates have been reported in the pale grass blue butterfly, Zizeeria maha , since the Fukushima nuclear accident. However, it remains uncertain if these effects are restricted to this butterfly. Here, we evaluated the effects of ingesting cabbage leaves grown with contaminated soils from Fukushima on the development and hemocytes of the cabbage white butterfly, Pieris rapae . Contaminated cabbage leaves containing various low levels of anthropogenic 134 Cs and 137 Cs radioactivity (less than natural 40 K radioactivity) were fed to larvae from Okinawa, the least contaminated locality in Japan. Negative developmental and morphological effects were detected in the experimental groups. The cesium (but not potassium) radioactivity concentration was negatively correlated with the granulocyte percentage in hemolymph, and the granulocyte percentage was positively correlated with the pupal eclosion rate, the adult achievement rate, and the total normality rate. These results demonstrated that ingesting low-level radiocesium contaminants in Fukushima (but not natural radiopotassium) imposed biologically negative effects on the cabbage white butterfly, as in the pale grass blue butterfly, at both cellular and organismal levels.

Observation of morphological abnormalities in silkworm pupae after feeding 137CsCl-supplemented diet to evaluate the effects of low dose-rate exposure

“…One of the critical differences between our study and earlier studies is in previous studies, plants contaminated by the transfer of radiocesium from the soil were used to feed lepidopterans [20][21][22][23] . In contrast, in our study, the silkworm was fed an artificial diet directly supplemented with 137 CsCl solution.…”

“…Several internal exposure experiments have been conducted in wild lepidopterans such as Z. maha and P. rapae , which were collected after the Fukushima nuclear accident 20 – 23 . However, it is difficult to discuss the effects of radiation exposure on these lepidopterans, because the absorbed dose has not been estimated in these previous studies.…”

“…These experiments have showed high mortality and morphological abnormalities in the butterfly at low levels of exposure. Taira et al 23 also conducted an internal exposure experiment in the cabbage white butterfly, Pieris rapae, using radiocesium-contaminated leaves and observed developmental and morphological abnormalities. These results suggest that the lepidopterans are highly sensitive to radiocesium internal exposure; thus, accurate absorbed dose estimation is required.…”

The Pale Grass Blue Butterfly as an Indicator for the Biological Effect of the Fukushima Daiichi Nuclear Power Plant Accident

“…We observed morphological abnormalities in this butterfly [23]. Importantly, the percentage of granulocytes among hemocytes in this butterfly was inversely correlated with radioactive Cs concentration of cabbage leaves ingested but not with the potassium radioactivity concentration [23]. These results demonstrated that the high sensitivity of the pale grass blue butterfly to internal exposures was not exceptional.…”

“…We cultivated cabbage using contaminated soils collected from Fukushima to feed larvae from Okinawa. We observed morphological abnormalities in this butterfly [23]. Importantly, the percentage of granulocytes among hemocytes in this butterfly was inversely correlated with radioactive Cs concentration of cabbage leaves ingested but not with the potassium radioactivity concentration [23].…”