Population structure of the predatory mite Neoseiulus womersleyi in a tea field based on an analysis of microsatellite DNA markers

The predatory mite Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae) is an important natural enemy of the Kanzawa spider mite, Tetranychus kanzawaki Kishida (Acari: Tetranychidae), in tea fields. Attraction and preservation of natural enemies by habitat management to reduce the need for acaricide sprays is thought to enhance the activity of N. womersleyi. To better conserve N. womersleyi in the field, however, it is essential to elucidate the population genetic structure of this species. To this end, we developed ten microsatellite DNA markers for N. womersleyi. We then evaluated population structure of N. womersleyi collected from a tea field, where Mexican sunflower, Tithonia rotundifolia (Mill.), was planted to preserve N. womersleyi. Seventy-seven adult females were collected from four sites within 200 m. The fixation indexes FST among subpopulations were not significantly different. The kinship coefficients between individuals did not differ significantly within a site as a function of the sampling dates, but the coefficients gradually decreased with increasing distance. Bayesian clustering analysis revealed that the population consisted of three genetic clusters, and that subpopulations within 100 m, including those collected on T. rotundifolia, were genetically similar to each other. Given the previously observed population dynamics of N. womersleyi, it appears that the area inhabited by a given cluster of the mite did not exceed 100 m. The estimation of population structure using microsatellite markers will provide valuable information in conservation biological control

Dynein light chain 1 functions in somatic cyst cells regulate spermatogonial divisions in Drosophila

Stem cell progeny often undergo transit amplifying divisions before differentiation. In Drosophila, a spermatogonial precursor divides four times within an enclosure formed by two somatic-origin cyst cells, before differentiating into spermatocytes. Although germline and cyst cell-intrinsic factors are known to regulate these divisions, the mechanistic details are unclear. Here, we show that loss of dynein-light-chain-1 (DDLC1/LC8) in the cyst cells eliminates bag-of-marbles (bam) expression in spermatogonia, causing gonial cell hyperplasia in Drosophila testis. The phenotype is dominantly enhanced by Dhc64C (cytoplasmic Dynein) and didum (Myosin V) loss-of-function alleles. Loss of DDLC1 or Myosin V in the cyst cells also affects their differentiation. Furthermore, cyst cell-specific loss of ddlc1 disrupts Armadillo, DE-cadherin and Integrin-βPS localizations in the cyst. Together, these results suggest that Dynein and Myosin V activities, and independent DDLC1 functions in the cyst cells organize the somatic microenvironment that regulates spermatogonial proliferation and differentiation

Search for the rare decay B-0 ->tau(+)tau(-) at BABAR

We present the results of a search for the decay B-0 ->tau(+)tau(-) in a data sample of (232 +/- 3)x10(6) Upsilon(4S)-> BB decays using the BABAR detector. Certain extensions of the standard model predict measurable levels of this otherwise rare decay. We reconstruct fully one neutral B meson and seek evidence for the signal decay in the rest of the event. We find no evidence for signal events and obtain B(B-0 ->tau(+)tau(-))< 4.1x10(-3) at the 90% confidence level

Occurrence, population dynamics and winter phenology of spider mites and their phytoseiid predators in a citrus orchard in Syria

International audienceThe present study aimed to clarify some bio-ecological aspects of phytoseiid and tetranychid mites in Syrian citrus orchard conditions. The main objective was to obtain preliminary data on diversity, population dynamics, and overwintering phenology of mites considered in a pesticide-free citrus orchard located in Latakia province. Mites were collected on citrus leaves, in Phyto traps attached to citrus twigs, and on wild plants within and around the orchard from mid-summer 2013 to early summer 2014. Panonychus citri was the main tetranychid species collected on citrus leaves, but in very low densities. Mobile stages of this phytophagous were absent during winter. Eight phytoseiid species were found on citrus leaves during all sampling dates, and their general mean density was four times higher compared to that of P. citri. Euseius stipulatus, Euseius scutalis and Amblyseius andersoni were the dominant species on citrus leaves and seemed to have different population dynamics, different overwintering sites and phenology in winter, apparently due to differences in climatic requirements (i.e. temperature and photophase). Some phytoseiid species were rarely observed on citrus leaves, but were collected in high number in Phyto traps. Others seemed to emigrate from wild plants to overwinter on citrus twigs. Several hypotheses were formulated to explain the results obtained