Reproductive competition between females in the matrilineal Mosuo of southwestern China

The matrilineal Mosuo of southwestern China live in communal households where brothers and sisters of three generations live together (duolocal residence), and men visit their wives, who reside elsewhere, only at night in ‘visiting’ marriages. Here we show that these communally breeding sisters are in reproductive conflict, in the sense that they share the resources needed to reproduce. We analyse determinants of reproductive success in females and males, and show that co-resident female kin are in competition; the more female kin reside in the household, the more reproductive success is reduced. Male reproductive success, however, is not determined by the kin in his natal household; duolocal males are not in reproductive conflict with their siblings. Competition with female cousins can be worse than that between sisters. We also find that female work on the farm (which is the main communal resource) is not equal. We use a ‘tug-of-war’ model of reproductive skew generated by incomplete control, to model the patterns of effort put into competition between sisters and cousins. The model predicts that more dominant (older) sisters will put less effort into reproductive conflict than will less dominant (younger) sisters; but younger sisters will also have lower reproductive success because they are less efficient at gaining access to the shared resource. Both predictions are consistent with our data. Younger sisters work less in the fields than do older sisters, which may represent a form of conflict or may be because their average relatedness to the household is lower than that of their more fertile older sisters.     

Effect of relative humidity on population growth of <Emphasis Type="Italic">Apolygus lucorum</Emphasis> (Heteroptera: Miridae)

Apolygus lucorum (Meyer-Dür) (Heteroptera: Miridae) is a significant insect pest of cotton, Chinese dates, grapes and many other crops in China, and its populations typically increase after heavy rains. However, the intrinsic mechanism of the rainfall-dependent outbreak is not yet fully understood. In our study, the effect of different relative humidity (RH), 40, 50, 60, 70, and 80% RH, on population growth of A. lucorum was evaluated in the laboratory. High humidity (e.g. 70 and 80% RH) was observed to significantly increase egg and nymph survival, prolong adult life longevity, and improve female fecundity. However, low humidity (e.g. 40 and 50% RH) led to unfavorable effects on survival and fecundity. As a result, the intrinsic capacity for increase (r _m), net production (R _o), and the finite rate of increase (λ) of A. lucorum population greatly increased with increasing relative humidity. Additionally, the relationships between r _m and R _o and relative humidity were good fits to the logistic models y = 36.82/(1 + Exp(10.76 − 0.19x)) (p < 0.001) and y = 0.10/(1 + Exp(9.26 − 0.19x)) (p = 0.003), respectively. This study provides insight into the phenology of A. lucorum, and may contribute to modeling of its population dynamics.     

Network dynamics in nociceptive pathways assessed by the neuronal avalanche model

ABSTRACT: BACKGROUND: Traditional electroencephalography provides a critical assessment of pain responses. The perception of pain, however, may involve a series of signal transmission pathways in higher cortical function. Recent studies have shown that a mathematical method, the neuronal avalanche model, may be applied to evaluate higher-order network dynamics. The neuronal avalanche is a cascade of neuronal activity, the size distribution of which can be approximated by a power law relationship manifested by the slope of a straight line (i.e., the alpha value). We investigated whether the neuronal avalanche could be a useful index for nociceptive assessment. FINDINGS: Neuronal activities were recorded with 4 X 8 multichannel electrode arrays in the primary somatosensory cortex (S1) and anterior cingulate cortex (ACC). Under light anesthesia, peripheral pinch stimulation increased the slope of the alpha value in both the ACC and S1, whereas brush stimulation increased the alpha value only in the S1. The increase in alpha values was blocked in both regions under deep anesthesia. The increase in alpha values in the ACC induced by peripheral pinch stimulation was blocked by medial thalamic lesion, but the increase in alpha values in the S1 induced by brush and pinch stimulation was not affected. CONCLUSIONS: The neuronal avalanche model shows a critical state in the cortical network for noxious-related signal processing. The alpha value may provide an index of brain network activity that distinguishes the responses to somatic stimuli from the control state. These network dynamics may be valuable for the evaluation of acute nociceptive processes and may be applied to chronic pathological pain conditions.     

A remarkable new genus of leafhoppers (Hemiptera,Cicadellidae, Iassinae) from Southeast Asia

Tardrabassus pakneunensis, n. gen. & sp. is described and illustrated. The new genus shows morphological affinities to three leafhopper subfamilies, Tartessinae, Deltocephalinae, and Iassinae, but is tentatively placed in Iassinae based on the position of the ocelli, the reduced lateral frontal sutures, the leg chaetotaxy, and the structure of the male genitalia.     

Chemical Constituents from a Mangrove-Derived Actinobacteria Isoptericola chiayiensis BCRC 16888 and Evaluation of Their Anti-NO Activity

Cultivation of the actinobacteria strain Isoptericola chiayiensis, a mangrove - derived actinobacteria that was isolated from a mangrove soil collected in Chiayi County, resulted in the isolation of one new 2-furanone derivative, isopterfuranone ( 1 ), one new sesquiterpenoid, isopterchiayione ( 2 ), one new benzenoid derivative, isopterinoid ( 3 ), five new flavonoids, chiayiflavans A−E ( 4 – 8 ), and 4 metabolites isolated for the first time from nature source, methyl 3-(4-methyl-2,5-dioxopyrrolidin-3-yl)propanoate ( 9 ), 3-ethyl-4-methylpyrrolidine-2,5-dione ( 10 ), chiayiensol ( 11 ) and chiayiensic acid ( 12 ). Their structures were determined through in-depth spectroscopic and mass-spectrometric analyses. Most of the isolates showed potent inhibitory effects on NO production in LPS-stimulated RAW 264.7 murine macrophages cells with IC₅₀ values ranging from 9.36 to 40.02 μM. Of these isolates, 4 and 5 showed NO inhibitory activity with IC₅₀ values of 17.14 and 9.36 μM, stronger than the positive control quercetin (IC₅₀=36.95 μM). This is the first report on flavan metabolites from the genus Isoptericola.