The putative brain photoperiodic photoreceptors in the vetch aphid, Megoura viciae

In an attempt to identify the brain photoreceptors that mediate the photope riodic response of the vetch aphid, Megoura viciae, we utilised immunocytoc hemical techniques and employed 20 antibodies directed against invertebrate and vertebrate opsins and phototransduction proteins. A sub-set of these a ntibodies (to Drosophila rhodopsin I: RH1-1; vertebrate cone opsins: COS-1; CERN-874; CERN-933, vertebrate rod opsin: CERN-901; vertebrate arrestin: A B-Arr; vertebrate transducin+arrestin+rhodopsin kinase+cGMP phosphodiestera se: CERN-911; and vertebrate cellular retinoid binding protein: CRALBP) con sistently labelled an anterior ventral neuropile region of the protocerebru m. These anatomical findings, coupled with previous localised illumination and micro-lesion studies, provide strong evidence that this region of the a phid brain houses the photoperiodic photoreceptors. The present study also confirms that the medial (Group I) neurosecretory cells are not the photope riodic photoreceptors. (C) 1999 Elsevier Science Ltd. All rights reserved.