Trichoplusia ni (Lepidoptera: Noctuidae) somatic and immune response alterations by electromagnetic fields

Power lines have generated a significant increase in electromagnetic fields (EMF) in natural ecosystems. Insects are widely used to measure EMF effect; however there are few studies on the effect on Lepidoptera pests metabolism. Our objective was to evaluate the effect of EMF on the development and immune response of the cabbage looper Trichoplusia ni (Hübner). Neonates, third instar larvae, pupae and adults were exposed for 48 h to 2 millitesla (mT). Adults from EMF exposed pupae hatched one day earlier (from 8 d total), but no changes in laid eggs number or larvae hatching was observed compared with the unexposed controls.  In regard to cellular immune response after EMF exposure, third instar larvae showed decreased hemocyte total number compared with unexposed controls (1055±397 vs. 2004±217, respectively).  Semi-quantitative RT-PCR analysis revealed an increase of several humoral immune response marker genes, involving increased expression of apoptosis-associated caspase (86% increase), levocin (75% increase), peptidoglycan recognition protein (46% increase), gallerimycin (44% increase), phenoloxidase (29% increase), defensin (25% increase), globerin (14% increase), and attacine (11% increase) The antimicrobial peptides that showed a reduced expression was cecropin (42% decrease) and lysozyme (8%). The time reduced adult hatching and the enhancement of cellular and humoral immunity in EMF exposed cabbage looper larvae, in response to species preservation strategy, is discussed.