How bottom-up effects of different tomato cultivars affect population responses of Tuta absoluta (Lep.: Gelechiidae): a case study on host plant resistance
ARTHROPOD-PLANT INTERACTIONS
Authors: Heidari, Nasrin; Sedaratian-Jahromi, Amin; Ghane-Jahromi, Mojtaba; Zalucki, Myron P.
Abstract
The Gellechiid moth, Tuta absoluta (Meyrick), causes severe problems in many tomato-growing regions worldwide. The present study investigated bottom-up effects under laboratory conditions (25 +/- 1 degrees C, 65 +/- 5% R.H., and 16 h L.P.) of six commercial tomato cultivars ('Rio grand', 'Atrak', 'Super strain B', 'Unigen', 'King ston', and 'Estern') on biological traits of this pest. The results obtained evaluated with age-stage, two-sex life table. Duration of different life stages and adult fecundity of this pest were strongly affected by cultivars tested. The highest and lowest mortality of pre-adult stages were estimated on the 'Atrak' (36 +/- 5%) and 'King ston' (15 +/- 3%), respectively. Tomato cultivars significantly affected population parameters of T. absoluta. The net reproductive rate (R-0) was highest on the 'King ston' (97 +/- 11.8 offspring/individual). The finite (lambda) and intrinsic (r) rates of population increase were dramatically lower on the cultivar 'Atrak'. Under laboratory conditions, the cultivars 'Atrak' and 'King ston' had the highest and least resistance level to this pest, respectively. Host plant resistance will be foundational to developing integrated pest management programs.
Dynamic Causal Modelling of the Reduced Habituation to Painful Stimuli in Migraine: An EEG Study
BRAIN SCIENCES
Authors: Bassez, Iege; Van de Steen, Frederik; Ricci, Katia; Vecchio, Eleonora; Gentile, Eleonora; Marinazzo, Daniele; de Tommaso, Marina
Abstract
A consistent finding in migraine is reduced cortical habituation to repetitive sensory stimuli. This study investigated brain dynamics underlying the atypical habituation to painful stimuli in interictal migraine. We investigated modulations in effective connectivity between the sources of laser evoked potentials (LEPs) from a first to final block of trigeminal LEPs using dynamic causal modelling (DCM) in a group of 23 migraine patients and 20 controls. Additionally, we looked whether the strength of dynamical connections in the migrainous brain is initially different. The examined network consisted of the secondary somatosensory areas (lS2, rS2), insulae (lIns, rIns), anterior cingulate cortex (ACC), contralateral primary somatosensory cortex (lS1), and a hidden source assumed to represent the thalamus. Results suggest that migraine patients show initially heightened communication between lS1 and the thalamus, in both directions. After repetitive stimulations, connection strengths from the thalamus to all somatosensory areas habituated in controls whereas this was not apparent in migraine. Together with further abnormalities in initial connectivity strengths and modulations between the thalamus and the insulae, these results are in line with altered thalamo-cortical network dynamics in migraine. Group differences in connectivity from and to the insulae including interhemispheric connections, suggests an important role of the insulae.