Nesting substrata, colony success and productivity of the wasp Mischocyttarus cassununga

Nesting substrata, colony success and productivity of the wasp Mischocyttarus cassununga. Colonies of the wasp Mischocyttarus cassununga (von Ihering, 1903) are easily found in urban areas. However, in spite of the massive presence of this species in cities, little is known about its nesting habits, colony success and productivity. The present study aimed at answering the following questions: What are the substrates used for nesting by M. cassununga? What is the main foundation strategy adopted by M. cassununga in urban areas: a solitary female or associative foundation? Is there a relationship between foundation strategies and colony success? Is the total number of cells per nest related to the number of adults produced? The study was conducted in Juiz de Fora, southeastern Brazil, from December 2006 to November 2007. Nesting in man-made substrata seems to be a common strategy in M. cassununga (90.9%), with preference for nest building with a horizontal comb facing north. The colonies were established mainly by groups of foundresses (67.6%), with a success of 84%. The number of brood cells produced per nest was 71.74 ± 45.25 (18-203), and it was positively correlated with the number of adults produced. Hence, we can say that the nests founded by M. cassununga are located mainly in man-made substrata and mostly founded by a group of females. The cell reuse behavior increases the number of adults produced, as it optimizes foraging. These characteristics together with its behavior and nesting habits promote the success of this species in thriving in urban environments.

Is the capture success of orchid bees (Hymenoptera, Apoidea) influenced by different baited trap designs? A case study from southern Brazil

Orchid bees are increasingly applied on Neotropical biomonitoring and bioindication studies due to the relative easiness of sampling and identification when compared to other bee groups. A considerable number of orchid bee community studies have been adopting baited traps as a sampling method, especially for replication purposes. However, the trap attributes are variable, and hitherto no evaluation of different designs was carried out. Here, five attributes of baited traps were tested: trap volume, number of entrance holes, presence of landing platform, kind of landing platform, and fixation content. We use Mann-Whitney tests to access differences in richness and abundance capture rates for each trap design. We found that volume, number of entrance holes, and fixation content do not influence orchid bees capture. However, the design without landing platforms had a significantly higher capture rate for richness when compared with sanded landing platforms. On the other hand, analyzing the kind of landing platform, we detected a significantly higher richness and abundance for the trap with landing platforms glued with sand. Despite the fact that the effects of different designs tested here were very punctual, we consider that results from samples taken with different baited trap designs are comparable. Some adjustments on trap design can be done according to the particularities of future studies.

Biology and reproductive capacity of Spodoptera eridania (Cramer) (Lepidoptera, Noctuidae) in different soybean cultivars

This study aimed to evaluate the development, survival and reproductive capacity of Spodoptera eridania in four soybean cultivars. The experiment was conducted in the laboratory, in a climatic chamber at 25 °C ± 1 °C, 70 ± 10% relative humidity and 12 h photophase. The cultivars used were: FMT Tabarana, BRS/MT Pintado, FMT Tucunaré and Monsoy 8757, all conventional cultivars with medium cycles. All cultivars tested allowed the development of S. eridania. However, Monsoy 8757 was the cultivar that most affected the prolonged in the duration larval, pupal and total cycle, showed lower pupal weight as well as reduction in the intrinsic rate increase. These results contribute to the management of this species in regions of outbreaks in soybean areas.

Annual reproductive cycle and fecundity of Scorpaena notata (Teleostei, Scorpaenidae)

Scorpaena notata (Teleostei: Scorpaenidae) is an oviparous species with external fertilisation that shows some unusual features in its gonadal morphology and gametogenesis. In this work we analyse the annual reproductive cycle and the fecundity of this species by studying the monthly histological changes in the gonads and of various indices related to reproduction. Sexual dimorphism does not occur in the population we studied, which is clearly dominated by males. Multiple spawning takes place between July and October, consisting of between 6,000 and 33,000 eggs per female, each of about 500 µm in diameter. The fecundity of the species is determined by the size and weight of the individuals

Improving college access and success for low-income students: Evidence from a large need-based grant program

Using comprehensive administrative data on France's single largest financialaid program, this paper provides new evidence on the impact of large-scaleneed-based grant programs on the college enrollment decisions, persistenceand graduation rates of low-income students. We exploit sharp discontinuitiesin the grant eligibility formula to identify the impact of aid on student outcomesat different levels of study. We find that eligibility for an annual cashallowance of 1,500 euros increases college enrollment rates by up to 5 percentagepoints. Moreover, we show that need-based grants have positive effectson student persistence and degree completion.

Diet and breeding success of long-eared owls in a semi-arid environment

Only a few studies, and mostly in temperate climates in Europe, have examined the breeding and diet of long-eared owls (Asia otus) compared to studies of cavity-breeding owls, possibly because of the difficulties in reaching the nests of the former. Here we studied a population of long-eared owls, monitoring the diet of breeding owls and that of owls at a communal roost, every two to three months during 2006 -2009, in a semi-arid region in Israel. It was found that the studied owls produced more young than in most countries in Europe. Diet was not associated with breeding parameters of the owls, whereas laying date was negatively correlated with both clutch size and number of nestlings. We found that more social voles (Microtus socialis) and fewer birds and house mice (Mus musculus) made up the diet at nests than that of adults at the roosts. The diet and breeding of long-eared owls in Israel differ from that in Europe, with birds and mice comprising an important part of the diet, in addition to voles.

Compartmentalized secretory leukocyte protease inhibitor expression and hormone responses along the reproductive tract of postmenopausal women

Immunity and hormonal responses in the reproductive tissues of postmenopausal women are poorly understood. Secretory leukocyte protease inhibitor (SLPI), a multifunctional antimicrobial protein expressed at mucosal surfaces, is thought to play a key role in infectious and inflammatory contexts. The aim of this study was to measure SLPI production along the female reproductive tract in postmenopausal women with and without hormonal treatment. We additionally quantified estrogen receptor alpha (ERα) and progesterone receptor A (PRA) in these tissues. Expression of SLPI was decreased in the vagina and ectocervix of women under hormonal treatment. Endocervical ERα mRNA expression was increased while this did not reach significance at the protein level. SLPI expression in the endometrium was not influenced by hormonal treatment. We observed attenuated ERα expression in the cervix and endometrium of hormonally treated women, whereas vaginal expression was increased. PRA expression was augmented in the cervix and endometrium and unchanged in the vagina. Taken together, our results indicate that hormonal responses and receptor expression are differentially regulated in vaginal tissue compared with the cervix and endometrium.

Experimental evidence that intra-specific competition in seagrass meadows reduces reproductive potential in the sea urchin Paracentrotus lividus (Lamarck)

To better understand the biological controls that regulate sea urchin dynamics, we studied the effects of potential inter- and intra-specific competition for food on several biological variables of the main sea urchin in the Mediterranean (Paracentrotus lividus). We carried out a caging experiment in which we manipulated sea urchin density (natural vs. high density) and herbivorous fish (Sarpa salpa) accessibility (free access vs. exclusion) in a Posidonia oceanica meadow. No evidence of competition between fish and urchins was detected. Neither density-dependent mortality nor changes in the somatic variables were found; however, we detected that intra-specific competition affected the reproductive potential of P. lividus. The gonad index of urchins at high population densities was ca. 30% lower than that of urchins at natural densities. As a spawning event had just occurred when urchins were collected, these differences probably reflect differences in reserve content, which may compromise the following reproductive period and decrease survival in the long term, as the gonads are also used as storage organs. For the time period studied, mortality rates appeared to be independent of local densities. The results indicate that a long-term negative feedback mechanism appears to take place in P. lividus in response to increased population density.

Genetic diversity and ecological success of Staphylococcus aureus strains colonizing humans.

The genetic determinants and phenotypic traits which make a Staphylococcus aureus strain a successful colonizer are largely unknown. The genetic diversity and population structure of 133 S. aureus isolates from healthy, generally risk-free adult carriers were investigated using four different typing methods: multilocus sequence typing (MLST), amplified fragment length polymorphism analysis (AFLP), double-locus sequence typing (DLST), and spa typing were compared. Carriage isolates displayed great genetic diversity which could only be revealed fully by DLST. Results of AFLP and MLST were highly concordant in the delineation of genotypic clusters of closely related isolates, roughly equivalent to clonal complexes. spa typing and DLST provided considerably less phylogenetic information. The resolution of spa typing was similar to that of AFLP and inferior to that of DLST. AFLP proved to be the most universal method, combining a phylogeny-building capacity similar to that of MLST with a much higher resolution. However, it had a lower reproducibility than sequencing-based MLST, DLST, and spa typing. We found two cases of methicillin-resistant S. aureus colonization, both of which were most likely associated with employment at a health service. Of 21 genotypic clusters detected, 2 were most prevalent: cluster 45 and cluster 30 each colonized 24% of the carrier population. The number of bacteria found in nasal samples varied significantly among the clusters, but the most prevalent clusters were not particularly numerous in the nasal samples. We did not find much evidence that genotypic clusters were associated with different carrier characteristics, such as age, sex, medical conditions, or antibiotic use. This may provide empirical support for the idea that genetic clusters in bacteria are maintained in the absence of adaptation to different niches. Alternatively, carrier characteristics other than those evaluated here or factors other than human hosts may exert selective pressure maintaining genotypic clusters.

Alternative reproductive strategies in Formica lugubris Zett (Hymenoptera, Formicidae)

A long term study on the reproductive strategies of Formica lugubris (Formica rufa group) has revealed many new important facts. Within a supercolony the sex-ratio is strongly female biased. Some of the sexuals mate on the nest surface, whereas others fly from the nest. Those sexuals participating in flights aggregate in particular meadow sites (mating places). On these places females attract males by releasing a sex pheromone.

Risque thrombotique sous procréation médicalement assistée [Thrombotic risk in assisted reproductive technology].

Use of assisted reproductive technology (ART) is increasing in many developed countries. Arterial and venous thromboembolic complications are reported during ART with an incidence of 0.1%. The development of these events has been mainly ascribed to the presence of ovarian hyperstimulation syndrome (OHSS). Precise mechanisms by which OHSS and exogenous hormonal stimulation used in ART induce thromboembolic events remain unclear. However, vascular endothelial growth factor secreted during OHSS, high estradiol concentrations, and blood hyperviscosity play a major role in inducing a prothrombotic state. Therefore, before planning an ART, individual thromboembolic risk should be assessed and thromboprophylaxis offered to high risk patients. Prophylaxis should be initiated in women who develop moderate-to-severe OHSS.

Success of a general school-based physical activity intervention on bone mineral content depends on pubertal stage but not on gender

Aims: We performed a randomised controlled trial in children of both gender and different pubertal stages to determine whether a school-based physical activity (PA) program during a full schoolyear influences bone mineral content (BMC) and whether there are differences in response for boys and girls before and during puberty. Methods: Twenty-eight 1st and 5th grade classes were cluster randomised to an intervention (INT, 16 classes, n=297) and control (CON; 12 classes, n=205) group. The intervention consisted of a multi-component PA intervention including daily physical education during a full school year. Each lesson was predetermined, included about ten minutes of jumping or strength training exercises of various intensity and was the same for all children. Measurements included anthropometry (height and weight), tanner stages (by self-assessment), PA (by accelerometry) and BMC for total body, femoral neck, total hip and lumbar spine using dualenergy X-ray absorptiometry (DXA). Bone parameters were normalized for gender and tanner stage (pre- vs. puberty). Analyses were performed by a regression model adjusted for gender, baseline height, baseline weight, baseline PA, post-intervention tanner stage, baseline BMC, and cluster. Researchers were blinded to group allocation. Children in the control group did not know about the intervention arm. Results: 217 (57%) of 380 children who initially agreed to have DXA measurements had also post-intervention DXA and PA data. Mean age of prepubertal and pubertal children at baseline was 9.0±2.1 and 11.2±0.6 years, respectively. 47/114 girls and 68/103 boys were prepubertal at the end of the intervention. Compared to CON, children in INT showed statistically significant increases in BMC of total body (adjusted z-score differences: 0.123; 95%>CI 0.035 to 0.212), femoral neck (0.155; 95%>CI 0.007 to 0.302), and lumbar spine (0.127; 95%>CI 0.026 to 0.228). Importantly, there was no gender*group, but a tanner*group interaction consistently favoring prepubertal children. Conclusions: Our findings show that a general, but stringent school-based PA intervention can improve BMC in elementary school children. Pubertal stage, but not gender seems to determine bone sensitivity to physical activity loading.