Comparing memory-forming capabilities between laboratory-reared and wildLymnaea: learning in the wild, a heritable component of snail memory

Abstract

SUMMARYWe set out to determine whether the ability to form long-term memory (LTM) is influenced by laboratory rearing. We investigated the ability of four populations of Lymnaea stagnalis to form LTM following operant conditioning both in the freely behaving animal and at the electrophysiological level in a neuron, RPeD1, which is a necessary site for LTM. We hypothesized that laboratory rearing results in a decreased ability to form LTM because rearing does not occur in an ʻenriched environmentʼ. Of the four populations examined, two were collected in the wild and two were reared in the laboratory -specifically, (1) wild Dutch snails; (2) their laboratory-reared offspring; (3) wild Southern Alberta snails (Belly); and (4) their laboratory-reared offspring. We found that Belly snails had an enhanced capability of forming LTM compared with Dutch laboratory-reared snails. That is, the Belly snails, which are much darker in colour than laboratory-reared snails (i.e. blonds), were ʻsmarterʼ. However, when we tested the offspring of Belly snails reared in the laboratory we found that these snails still had the enhanced ability to form LTM, even though they were now just as ʻblondʼ as their laboratory-reared Dutch cousins. Finally, we collected wild Dutch snails, which are also dark, and found that their ability to form LTM was not different to that of their laboratory-reared offspring. Thus, our hypothesis was not proved. Rather, we now hypothesize that there are strain differences between the Belly and Dutch snails, irrespective of whether they are reared in the wild or in the laboratory.

Cognitive adaptation in asexual and sexual wasps living in contrasted environments

“…The possibility of an absence of selective pressure in stable environments on learning abilities may also explain these results [79]: in such a case, thelytokous wasps would only exhibit ancestral abilities. This argument is supported by observation data in a 50-years lab reared Lymnaea strain, which was shown to have similar learning abilities as the wild strain [80]. …”

Environmental effects on Drosophila brain development and learning

“…The brain tends to retain its authenticity in genetically determined development and function under a certain range of situations. Likewise, laboratory rearing of snails did not reduce their capability to form memories compared with nurturing in the wild (Orr et al, 2008). These authors proposed that either their laboratory rearing conditions were not sufficiently impoverished to affect brain development and memory ability or the behavior they examined may have been resistant to environmental challenges during development.…”

How Stress Alters Memory in ‘Smart’ Snails

“…However, there is growing evidence that L. stagnalis populations differ, both in their response to environmental stimuli [19], [24], [25], [26] and also in their ability to form long-term memory [15], [27], [28]. Cognitive ability and the response to stress is also consistent across successive generations, both in the laboratory and in the field, indicating a genetic basis to these responses [15], [29], [30].…”