Effect of photoperiod and light intensity on learning ability and memory formation of the pond snail Lymnaea stagnalis

Abstract

Natural light is regarded as a key regulator of biological systems and typically serves as a Zeitgeber for biological rhythms. As a natural abiotic factor, it is recognized to regulate multiple behavioral and physiological processes in animals. Disruption of the natural light regime due to light pollution may result in significant effects on animal learning and memory development. Here, we investigated whether sensitivity to various photoperiods or light intensities had an impact on intermediate-term memory (ITM) and long-term memory (LTM) formation in the pond snail Lymnaea stagnalis. We also investigated the change in the gene expression level of molluscan insulin-related peptide II (MIP II) is response to the given light treatments. The results show that the best light condition for proper LTM formation is exposure to a short day (8 h light) and low light intensity (1 and 10 lx). Moreover, the more extreme light conditions (16 h and 24 h light) prevent the formation of both ITM and LTM. We found no change in MIP II expression in any of the light treatments, which may indicate that MIP II is not directly involved in the operant conditioning used here, even though it is known to be involved in learning. The finding that snails did not learn in complete darkness indicates that light is a necessary factor for proper learning and memory formation. Furthermore, dim light enhances both ITM and LTM formation, which suggests that there is an optimum since both no light and too bright light prevented learning and memory. Our findings suggest that the upsurge of artificial day length and/or night light intensity may also negatively impact memory consolidation in the wild.

Effects of Artificial Light at Night on Fitness-Related Traits of Sea Urchin (Heliocidaris crassispina)

“…The potential influence of light pollution on growth and development also extends to mollusks. Research unveiled a correlation between daily light exposure duration and the growth pace and stored energy levels in the pulmonate Lymnaea stagnalis [51]. These outcomes find alignment with investigations on rodents, specifically Myotis emarginatus, showcasing that light pollution diminishes consumption rates and impedes the growth of juvenile and suckling bats [52].…”

Molecular cloning and expression analysis of CDK genes during selective and wild populations of juvenile Meretrix meretrix

“…These results suggest that light may play an important role in the growth, movement, reproduction, foraging and anti‐predation of bivalves (Wu et al, 2015). However, there is an optimum light intensity since both no light and too bright light prevented learning and memory (Hussein et al, 2020). In this study, light intensity had significant effect on the growth of M. meretrix ( p < 0.05), and the shell length of M. meretrix reared in the high light (2.16–778 Lux) is significantly higher than that in the low light (1.48–70.6 Lux) ( p < 0.05), which suggests that clams thrive better in suitable light intensity than in dark.…”

The genome of the simultaneously hermaphroditic snail Lymnaea stagnalis reveals an evolutionary expansion of FMRFamide-like receptors

“…More recently, knowledge of fundamental neuro-biological processes has provided important insight into learning and memory in L. stagnalis, and how these processes are disturbed by human and/or environmental factors (e.g. 15,16,17 ). Likewise, ecotoxicological compounds and immune elicitors in the environment have been shown to affect this species in terms of behavioural, developmental, endocrine, immunological and oxidative stress responses (e.g., 18,[19][20][21][22][23][24] ).…”