Influence of ultraviolet radiation on selected physiological responses of earthworms

Abstract

SUMMARY The purpose of this study was to investigate the adverse effects of ultraviolet (UV) radiation on earthworms. Earthworms that crawl out of the soil may die within a few hours after sunrise. This study shows that UV exposure can be lethal. In general, UV-B had a stronger damaging effect than UV-A. Different species of earthworms had different tolerances to UV exposure. In this study, Pontoscolex corethrurus showed the highest tolerance of the three tested species to UV radiation, while Amynthas graciliswas the most sensitive. UV radiation induced both acute and chronic responses. The acute response, which occurred immediately on or after UV exposure, was characterized by the appearance of abnormally strong muscle contractions,including S-shaped movements and jumping behavior, possibly caused by bad coordination between the circular and longitudinal muscles. The chronic response included damage to the skin and muscle cells, which resulted in a high mortality rate. Oxygen consumption by A. gracilis was significantly decreased after exposure to UV-A or UV-B. Since the circulation in earthworms is mediated by muscle contraction and the skin is the main organ of respiration, it is reasonable to expect that abnormal muscle contraction and a damaged epithelium could cause suffocation. Because of their sensitive responses, we propose that some earthworms, such as A. gracilis,could serve as a new model for studying UV-induced photodamage.

Increasing temperature within thermal limits compensates negative ultraviolet‐B radiation effects in terrestrial and aquatic organisms

“…This study revealed that terrestrial animals are also negatively affected by increased UV-B radiation, although the comparisons between animals and plants might be biased due to the uneven sampling size. Our finding is in good agreement with previous studies that documented that terrestrial animals such as earthworms are sensitive to direct exposure to UV-B radiation (Chuang, Lai, & Chen, 2006;Edwards, 2013). Besides direct exposure effects, indirect effects via UV-B induced changes in the chemical composition of plant material might additionally influence terrestrial animals.…”

Solar UVB and warming affect decomposition and earthworms in a fen ecosystem in Tierra del Fuego, Argentina

“…Previous field studies already demonstrated altered plant-animal interactions in terrestrial ecosystems by UVB radiation (Rousseaux et al, 1998;Salt et al, 1998;Gwynn-Jones, 1999;Convey et al, 2002;Veteli et al, 2003;Zaller et al, 2003;Rousseaux et al, 2004;Caputo et al, 2006). Although, earthworms are generally considered to be sensitive to direct exposure to UV radiation (Edwards & Bohlen, 1996;Chuang et al, 2006), in the present study epigeic earthworm population size remained unaffected by UVB radiation. This suggests that this earthworm species that is active on the soil surface also during the day is well protected from UVB radiation by their pigmentation (Sicken et al, 1999).…”

Enigmatic origin of massive Late Cretaceous-to-Neogene coprolite-like deposits in North America: a novel palaeobiological alternative to inorganic morphogenesis

“…It is widely recognized that earthworms upon death have strong muscle contractions, including sinuous movements likely caused by poor coordination between circular and longitudinal muscles (Chuang et al . ).…”

“…7), and to an unknown extent from contractions and reflexes induced during death and rigour mortis. It is widely recognized that earthworms upon death have strong muscle contractions, including sinuous movements likely caused by poor coordination between circular and longitudinal muscles (Chuang et al 2006).…”