Neuroscience Letters 371 (2004) 190–195 Exposure to hypomagnetic field space for multiple generations causes amnesia in Drosophila melanogaster Bin Zhang a,c , Huimin Lu a , Wang Xi b , Xianju Zhou b , Shiyu Xu a , Ke Zhang b , Jinchang Jiang a , Yan Li a , Aike Guo a,b,∗ a Laboratory of Visual Information Processing, Center for Brain and Cognitive Sciences, Institute of Biophysics, CAS, 15 Datum Road, Chaoyang District, Beijing 100101, China b Institute of Neuroscience, Shanghai Institutes for Biological Sciences, CAS, Shanghai 200031, China c Graduate School of the Chinese Academy of Sciences, China Received 13 July 2004; received in revised form 20 August 2004; accepted 28 August 2004 Abstract This is the introduction of Drosophila into the study of learning and memory affected by removal of the geomagnetic field (GMF) for successive generations. Using the operant visual learning/memory paradigm at a flight simulator, the present study revealed that wild-type flies raised in a hypomagnetic field environment continuously for 10 successive generations were gradually impaired in visual conditioning learning and memory formation and finally the 10th generation flies became morphs of nonlearners and completely amnesiac. The control experiments show that the impairment could not be ascribed to any apparent sensorimotor problems in Drosophila. The reverse shift from hypomagnetic field (HMF) to natural GMF restored the GMF-free induced amnesia fully after six consecutive generations. Thus, our findings demonstrate conclusively that some serious, but reversible learning and memory impairment may occur for living organisms in a prolonged separation from GMF over many consecutive generations. And Drosophila has the potential to develop into a new model organism for the study of the neurobiology of magnetism for multiple generations. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Drosophila; Flight simulator; Learning and memory; Hypomagnetic field Previous study has established a definite relationship between the most diverse properties of living organisms and earth’s geomagnetic field (GMF) [4]. A recent study has shown that an environment with a hypomagnetic field (HMF) caused a significant negative effect on memory formation in day-old chicks [16]. Whether HMFs affect the learning and memory ability for successive generations is unknown. It is difficult to test the effects of HMFs on learning and memory (L/M) for multiple generations with animals that have a long lifespan. Drosophila has a short lifespan (the average lifespan is about 50 days after eclosion), and they reproduce about 10 days after birth, whereas humans reproduce about 10,000 days after birth [12]. The molecular architecture ∗ Corresponding author. Tel.: +86 10 64888532/86 21 54921785; fax: +86 21 54921735. E-mail address: akguo@ion.ac.cn (A. Guo). of vertebrate and invertebrate nervous systems is mostly shared [3,18]. Drosophila has most – if not all – of the major neurotransmitters and molecules involved in synaptic vesicle release and recycling, receptors and channels necessary for neurotransmission as well as signal transduction mecha- nisms. Moreover, Drosophila’s nervous system is many orders of magnitude simpler than that of mammals, and its genetics are comparatively more sophisticated and rapid. Therefore, Drosophila has the potential to develop into a novel model organism for the study of the neurobiology of HMFs for multiple generations [1]. The compensated HMF space was produced by three pairs of Helmholtz coils 2.01, 1.80 and 1.61 m in diameter inter- secting one another vertically and by compensating the values of the geomagnetic field in vertical, north and south, and east and west direction, respectively. The value of the residual geomagnetic field resulting from this was 100–680 nT (the 0304-3940/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2004.08.072