Asexual reproduction and segmental regeneration, but not morphallaxis, are inhibited by boric acid in Lumbriculus variegatus (Annelida: Clitellata: Lumbriculidae)

Abstract

Body fragmentation, in some animal groups, is a mechanism for survival and asexual reproduction. Lumbriculus variegatus (Mu¨ller, 1774), an aquatic oligochaete worm, is capable of regenerating into complete individuals from small body fragments following injury and reproduces primarily by asexual reproduction. Few studies have determined the cellular mechanisms that underlie fragmentation, either regenerative or asexual. We utilized boric acid treatment, which blocks regeneration of segments in amputated fragments and blocks architomic fission during asexual reproduction, to investigate mechanistic relationships and differences between these two modes of development. Neural morphallaxis, involving changes in sensory fields and giant fiber conduction, was detected in amputated fragments in the absence of segmental regeneration. Furthermore, neural morphallactic changes occurred as a result of developmental mechanisms of asexual reproduction, even when architomy was prevented. These results show that fragmentation in L. variegatus, during injury or asexual reproduction, employs developmental and morphallactic processes that can be mechanistically dissociated by boric acid exposure. In regeneration following injury, compensatory morphallaxis occurred in response to fragmentation. In contrast, anticipatory morphallaxis was induced in preparation for fragmentation during asexual reproduction. Thus, various forms of regeneration in this lumbriculid worm can be activated independently and in different developmental contexts.

Boric acid as alternative reference substance for earthworm field tests

“…Beside the influence on soil pH and vegetation, boric acid can also inhibit the asexual reproduction and segmental regeneration of Clitellata (Martinez et al 2006), but this Mean and standard deviation for biomass (grams per square metre) of the species on the different treated plots. White control, grey 187 kg/ha, black 750 kg/ha.…”

Littoral Oligochaeta (Lumbriculidae and Enchytraeidae) communities of some mountain lakes in the Eastern Black Sea Range (Turkey)

“…It is tolerant of low pH; occurring even in peat bogs and temporary pools. This species also lives in shallow margins of ponds, where rapid environmental change and frequent predatory attacks may be common (MARTINEZ et al 2006).…”