Land abandonment as driver of woody vegetation dynamics in Tamaulipan thornscrub at Northeastern Mexico.

Background: Vegetation structure is defined as the temporal and spatial distribution of plant species in a particular site. Vegetation structure includes vertical and horizontal distribution and has been widely used as an indicator of successional changes. Ecological succession plays an essential role in the determination of the mechanisms that structure plant communities under anthropogenic disturbances. After an anthropogenic disturbance, such as grazing, forests follow changes in the original composition and vegetation structure, which eventually could restore some of their attributes to become mature forests again. To know how the time of abandonment affects woody plant communities, we ask the following questions: (1) How does the species richness, diversity, and vertical structure (A index) change concerning the time of abandonment? (2) Are species similarities among woody vegetation communities determined by land abandonment? (3) Which woody species have the highest ecological importance in each successional stage? Methods: We explored how successional stages after land abandonment mediated the species richness, species diversity (alpha and beta), and ecological importance value index on four areas of Tamaulipan thornscrub. We selected four areas that differed in time of abandonment: 10, 20, 30, and >30 years. The first three areas were used for cattle grazing, whereas the >30-year area was selected as a control since it does not have a record of disturbance by cattle grazing or agriculture. During the summer of 2012, we randomly established four square plots (40 m × 40 m) in each area, separated at least 200 m from each other. In each plot, we recorded all woody individuals per species with a basal diameter ≥1 cm at 10 cm above ground level. We estimated species richness indices, species diversity (alpha and beta), and ecological importance value index. Results: We recorded 27 woody species belonging to 23 genera and 15 families. Fabaceae accounted for 40% of the species. Acacia farnesiana was the most important and abundant species in the first three successional stages. We suggested that older successional stages of Tamaulipan thornscrub promote woody plant communities, characterized by a higher complex structure than younger communities. We observed the highest species similarity between the sites with a closer time of abandonment, while the lowest similarity was shown between the sites with extreme time of abandonment. We conclude that Tamaulipan thornscrub shows a similar trend of ecological succession to other dry forests and the time of abandonment has a high mediation on plant dynamics in the Tamaulipan thornscrub. Also, we stand out the importance of secondary forests for Tamaulipan thornscrub woody plant communities. Finally, we recommended future studies include aspects of regeneration speed, the proximity of mature vegetation, and the interactions of plants with their seed dispersers.

Natural Enemy Communities and Biological Control of Parthenolecanium spp. (Hemiptera: Coccidae) in the Southeastern United States.

We documented the species composition, seasonal ecology, and impacts of parasitoids and predators of Parthenolecanium corni (Bouché) and P. quercifex (Fitch) (Hemiptera: Coccidae) in the urban landscapes of Georgia, North Carolina, South Carolina, and Virginia, United States. Twenty-one parasitoid morphospecies and 12 predator species were collected through rearing, beat sheet, and sticky card trapping. Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae) was the most abundant parasitoid species in South Carolina, North Carolina, and Virginia, whereas Metaphycus sp. 2 (Hymenoptera: Encyrtidae) was the most abundant species in Georgia. Parasitism rates ranged from 59 to 92% in the nymphal population and 27 to 84% in the adult population in South Carolina. Blastothrix sp. 1 (Hymenoptera: Encyrtidae), C. lycimnia, Encyrtus sp. 1 (Hymenoptera: Encyrtidae), Eunotus sp., and Pachyneuron sp. (both Hymenoptera: Pteromalidae) emerged from adult scale insects and significantly reduced the fecundity of parasitized scale insects. Coccophagus lycimnia was the only parasitoid species emerged from nymphs. Hyperaspis signata (Olivier) species group, Chilocorus stigma Say (both Coleoptera: Coccinellidae), and Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) were the most abundant predators in South Carolina. The majority of natural enemies (87% of parasitoids and 82% of predators) were active from late March to late August and from late April to late October, respectively.

Life History of Parthenolecanium spp. (Hemiptera: Coccidae) in Urban Landscapes of the Southeastern United States.

This study was conducted to better understand the life history of Parthenolecanium corni (Bouché) and Parthenolecanium quercifex (Fitch) (Hemiptera: Coccidae), and to develop degree-day models for crawler emergence of the two soft scale species in Georgia, North Carolina, South Carolina, and Virginia. Both species were univoltine in the southeastern United States. In South Carolina, eggs hatched from mid-April to early June; second instars began to appear in September and migrated to twigs to overwinter in October; and third instars and adults appeared in mid-March to early April. Each parthenogenetic female produced on average 1,026 ± 52 eggs. Fecundity was positively correlated to the fresh weight, length, width, and height of gravid females. Gross reproductive rate (GRR) was 695.98 ± 79.34 ♀/♀, net reproductive rate (Rº) was 126.36 ± 19.03 ♀/♀, mean generation time (TG) was 52.61 ± 0.05 wk, intrinsic rate of increase (rm) was 0.04 ♀/♀/wk, and finite rate of increase (λ) was 1.04 times per week. Crawlers first occurred across Georgia, North Carolina, South Carolina, and Virginia in 2011-2013 when 524-596 Celsius-degree-days (DDC) had been accumulated with the single sine estimation method, or 411-479 DDC with the simple average method, at the base temperature of 12.8 °C and the start date of 1 January. These regional models accurately predicted the date of crawler emergence within 1 wk of the actual emergence in 2014.

General Biology and Current Management Approaches of Soft Scale Pests (Hemiptera: Coccidae).

We summarize the economic importance, biology, and management of soft scales, focusing on pests of agricultural, horticultural, and silvicultural crops in outdoor production systems and urban landscapes. We also provide summaries on voltinism, crawler emergence timing, and predictive models for crawler emergence to assist in developing soft scale management programs. Phloem-feeding soft scale pests cause direct (e.g., injuries to plant tissues and removal of nutrients) and indirect damage (e.g., reduction in photosynthesis and aesthetic value by honeydew and sooty mold). Variations in life cycle, reproduction, fecundity, and behavior exist among congenerics due to host, environmental, climatic, and geographical variations. Sampling of soft scale pests involves sighting the insects or their damage, and assessing their abundance. Crawlers of most univoltine species emerge in the spring and the summer. Degree-day models and plant phenological indicators help determine the initiation of sampling and treatment against crawlers (the life stage most vulnerable to contact insecticides). The efficacy of cultural management tactics, such as fertilization, pruning, and irrigation, in reducing soft scale abundance is poorly documented. A large number of parasitoids and predators attack soft scale populations in the field; therefore, natural enemy conservation by using selective insecticides is important. Systemic insecticides provide greater flexibility in application method and timing, and have longer residual longevity than contact insecticides. Application timing of contact insecticides that coincides with crawler emergence is most effective in reducing soft scale abundance.

The neurofibromin 1 type I isoform predominance characterises female population affected by sporadic breast cancer: preliminary data.

AIMS: Neurofibromin 1 (NF1) as a tumour suppressor gene can give rise to several transcripts by an alternative splicing event, generated at least for CELF cofactors. At present, the NF1 isoforms and CELF splicing transcripts in sporadic breast cancer are unknown. The aim of the authors was to detect NF1 gene expression, the NF1 isoform ratio and the CELF transcripts present in sporadic breast cancer. METHODS: Neurofibromin and RAS expression were analysed on tissue microarrays containing sporadic breast cancer (n=22), benign lesions (n=18, including six fibroadenomas, six fibrocystic changes and six ductal hyperplasias) and normal breast tissue (n=6) by immunohistochemistry assay. NF1 and CELF 3-6 RNA expression was performed by end point reverse transcription-PCR in the breast samples. RESULTS: NF1 and RAS expression in breast tissues showed no differential expression by immunohistochemistry results. Interestingly, the authors observed a shift transition in the isoform transcripts, from type II in normal breast tissue to type I isoform in breast carcinomas. CELF cofactor expression failed to be related with the shift transition of NF1 in breast tissues. CONCLUSIONS: These data suggest that there is a tendency for an NF1 expression shift transition from type II to type I isoform, which could comprise a significant event in the development and progression of sporadic breast cancer. This shift transition may not be related with CELF cofactors.