Baiwei Ma

The aphid Myzus persicae is an important agricultural pest relying on olfactory cues to find food and escape from predators. The considerable difficulty of anatomical manipulation and other related technical challenges may underlie the absence of studies systematically mapping the central projections of antennal sensory neurons in its central nervous system. We used mass stain, immunohistochemistry, laser scanning confocal microscope and three-dimensional reconstruction techniques to trace the central projections of sensory neurons from the antennae. The ipsilateral antennal nerve targets mainly the antennal lobe, the antennal mechanosensory and motor center, and most neuromeres of the ventral nerve cord. There are also several axons that project to other regions, like the contralateral antennal lobe, the contralateral antennal nerve, the ipsilateral calyx and some region of the protocerebrum. The numerous neuropils innervated by axons from the antenna indicate the multiple roles that this sensory organ serves in insect behavior, and the results which provide information about the basic anatomical arrangement of the olfactory nervous system in aphid M. persicae may provide some basic knowledge for the further investigations of the aphid.

Summary: The pollens which are rejected or ignored by the dry stigma can’t germinate since they haven’t acquired sugar solution from dry stigmas. But almost all research has ignored the participation of insects which may transport pollens from the nectar to stigmas, and that pollens may germinate on the dry stigma since they have soaked in the nectar. So, the key question is that whether insects carry pollens from nectar to the stigma. Since the adult Lepidoptera are important to the plant pollination and there is a general consensus that pollens are mainly deposited on the proboscis of adult Lepidoptera, and pollens are ubiquitous in the nectar of field flowers, we simulated the flower environment to conduct several groups of behavioral experiments in the adult Mythimna separata by controlling the presence, absence or movement of pollens in nectar, then counted and compared the proboscis pollens. We found that the pollens on the proboscis were mainly derived from the nectar. Our conclusion may contributes to the research of pollen germination on stigmas, especially the dry stigma, and also shows the importance of adult Lepidoptera to pollination, even supports the coevolution of Lepidoptera and angiosperm.