The Chalcidoidea bush of life: evolutionary history of a massive radiation of minute wasps.

Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra-conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first-instar larvae. The phylogeny suggests a transition from smaller soft-bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the "Angiosperm Terrestrial Revolution". Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3-180.5 Ma) and a crown age of 162.2 Ma (153.9-169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history.

Distance Dependent Contribution of Ants to Pollination but Not Defense in a Dioecious, Ambophilous Gymnosperm.

Dioecious plants are obligate outcrossers with separate male and female individuals, which can result in decreased seed set with increasing distance between the sexes. Wind pollination is a common correlate of dioecy, yet combined wind and insect pollination (ambophily) could be advantageous in compensating for decreased pollen flow to isolated females. Dioecious, ambophilous gymnosperms Ephedra (Gnetales) secrete pollination drops (PDs) in female cones that capture airborne pollen and attract ants that feed on them. Plant sugary secretions commonly reward ants in exchange for indirect plant defense against herbivores, and more rarely for pollination. We conducted field experiments to investigate whether ants are pollinators and/or plant defenders of South American Ephedra triandra, and whether their contribution to seed set and seed cone protection varies with distance between female and male plants. We quantified pollen flow in the wind and assessed the effectiveness of ants as pollinators by investigating their relative contribution to seed set, and their visitation rate in female plants at increasing distance from the nearest male. Ants accounted for most insect visits to female cones of E. triandra, where they consumed PDs, and pollen load was larger on bigger ants without reduction in pollen viability. While wind pollination was the main contributor to seed set overall, the relative contribution of ants was distance dependent. Ant contribution to seed set was not significant at shorter distances, yet at the farthest distance from the nearest male (23 m), where 20 times less pollen reached females, ants enhanced seed set by 30% compared to plants depending solely on wind pollination. We found no evidence that ants contribute to plant defense by preventing seed cone damage. Our results suggest that, despite their short-range movements, ants can offset pollen limitation in isolated females of wind-pollinated plants with separate sexes. We propose that ants enhance plant reproductive success via targeted delivery of airborne pollen, through frequent contact with ovule tips while consuming PDs. Our study constitutes the first experimental quantification of distance-dependent contribution of ants to pollination and provides a working hypothesis for ambophily in other dioecious plants lacking pollinator reward in male plants.

The Pronotum of Worker of Camponotus borellii Emery (Hymenoptera: Formicidae): How Can It Affect Performance of the Head, Work Division, and Development of the Worker Caste?

In polymorphic ants, whose workers display continuous size distribution, each subcaste occupies a phenotypic space, usually with diffuse morphological boundaries. These morphological differences are closely associated to size by allometry although the environment also plays a key role that affects the fitness of the species. In Camponotus borellii Emery, the species selected as a study model, workers exhibit a continuous increase in size; geometric morphometric (GM) was used over four morphological traits: head capsule, clypeus, pronotum, and mesosoma, in order to assess (1) changes in shape, among the worker caste; (2) the influence of allometry on such changes; and (3) pronotum shape in respect to the head so as to infer which factors may influence the polymorphic development of the worker caste. The results indicated that the pronotum is organized into two highly integrated functional modules (neck and shield), corresponding to one developmental module. GM shows a similar pattern to that obtained for linear morphometry, though the worker ratio was different along continuous size distribution due to shape changes in two traits, with are also useful for delimiting modular units: (1) rounded shape of the posterior region of the head in minor workers; (2) shape of the pronotum, especially its anterior region, henceforth, neck, which widens as a consequence of the higher development of its central region, henceforth, shield, in major workers. The relevance of these results is discussed regarding functional morphology (pronotum in relation to the head), work division, and development of the worker caste.

A new species of Limaytilla Casal, 1964 (Hymenoptera: Mutillidae) from Argentina, a key for the known species, and new record data for the Argentinian species.

A new species of Limaytilla from Argentina is described and illustrated based on males, L. diaguita Torréns Fidalgo sp. nov.. Diagnoses for both sexes of the genus and an illustrated key for the Argentinian species are provided as well as new record data for L. pampa Casal and L. pehuenche Casal. Habitus photographs of all Argentinian species and L. orlandoi Cambra, Quintero Pagliano from Chile, are also provided.

Description of the female of Colocharis hungi Torréns (Hymenoptera, Eucharitidae) and identification key for the species of Colocharis.

The female of Colocharis hungi Torréns (Hymenoptera: Eucharitidae) is newly described, detailing the characters that distinguish this species. In addition, we provide images and comments for C. hungi, diagnoses for all species of Colocharis Heraty, a key to species, and a distribution map for the species.

Two new species of Bradynobaenus Spinola, 1851 (Hymenoptera: Bradynobaenidae) in the semiarid area of Argentina.

Bradynobaenus diminutus Torréns & Fidalgo, sp. nov. and B. porteri Torréns & Fidalgo, sp. nov. (Argentina: La Rioja) are described and illustrated. A revised key of the genus is provided.

A new species of Pseudochalcura Ashmead (Chalcidoidea: Eucharitidae) from Argentina with descriptions of alternate sexes of two other species.

Pseudochalcura Ashmead is a genus of parasitic wasps within Eucharitidae (Chalcidoidea) that are all parasitoids of ants. The genus is widespread in the New World, with different species known from the Yukon and Alaska to northern Chile and Argentina. Descriptions of the adults (both sexes) of Pseudochalcura carinata sp. nov. from Argentina, and of the males of P. pauca Heraty and P. prolata Heraty are provided. A revised identification key to species is included.

Review of the genus Eotilla Schuster, 1949 (Hymenoptera: Bradynobaenidae: Typhoctinae: Eotillini) and description of new species from Argentina.

Diagnoses for the genus Eotilla Schuster, 1949 based on males and females, new generic and specific characters, descriptions of two new Argentinian species (Eotilla schusteri Torréns, Fidalgo, Roig-Alsina & Brothers, sp. nov. and E. medanito Torréns, Fidalgo, Roig-Alsina & Brothers, sp. nov., based on both sexes), a description of the female of E. superba Brothers, 1974 and redescriptions of the males of E. mickeli Schuster, 1949 and E. superba are provided. A key to the species of Eotilla is presented.

A new genus of Eucharitidae (Hymenoptera: Chalcidoidea), with notes on life history and immature stages.

Neolirata new genus (Eucharitidae: Eucharitini) is recognized based on males and females, with new descriptions of eggs, planidia and pupae. Redescriptions are provided for N. alta (Walker) and N. daguerrei (Gemignani) (comb. nov. transferred from Lirata) and a new description of N. furcula sp. nov. is presented. Females of N. alta deposit their eggs on the underside of leaves of Pseudabutilon virgatum (Cav.) Fryxell (Malvaceae) and N. daguerrei on the underside of Urvillea chacoensis Hunz (Sapindaceae). A key to species is included.

Description of the species of Dicoelothorax Ashmead (Chalcidoidea, Eucharitidae) and biology of D. platycerus Ashmead.

Descriptions of the adults of the two species of Dicoelothorax Ashmead, Dicoelothorax parviceps and Dicoelothorax platycerus, and the eggs, planidia and pupae of Dicoelothorax platycerus Ashmead are provided. Females of Dicoelothorax platycerus deposit their eggs on the underside of leaves of Pseudabutilon virgatum (Cav.) Fryxell (Malvaceae). The host of Dicoelothorax platycerus is Ectatomma brunneum Smith (Formicidae: Ectatomminae).

Relative androgen excess during the menopausal transition predicts incident metabolic syndrome in midlife women: study of Women's Health Across the Nation.

OBJECTIVE: During the menopausal transition, total testosterone (T) remains unchanged, whereas estrogen decreases markedly, creating a state of relative androgen excess. We hypothesized that change in the T-to-estradiol (T/E2) ratio during the menopausal transition would be associated with incident metabolic syndrome. METHODS: The association between incident metabolic syndrome and total E2, total T, sex hormone-binding globulin, the free androgen index, baseline total T/E2 ratio, and the change of this ratio over time was evaluated in a multiethnic cohort of 1,862 premenopausal and perimenopausal women without diabetes enrolled in the Study of Women's Health Across the Nation. RESULTS: New cases (n = 257) of metabolic syndrome were identified in the cohort during 6,296 woman-years of follow-up. The age-adjusted total T/E2 ratio increased by 10.1% per year during the 5 years of follow-up. Neither baseline nor change in E2 was associated with incident metabolic syndrome. Low sex hormone-biding globulin, free androgen index, and high total T at baseline all increased the risk of metabolic syndrome, but their change over time did not. Both baseline total T/E2 ratio (1.41; 95% CI = 1.17-1.69; P < 0.001) and its rate of change (1.24; 95% CI = 1.01-1.52; P < 0.04) were associated with increased incident metabolic syndrome independent of ethnicity. CONCLUSIONS: The interaction between T and E2 during the menopausal transition, rather than the individual change of each over time, is a factor in the determination of risk of developing metabolic syndrome during the menopausal transition. This relationship was independent of ethnicity and other factors associated with prevalent metabolic syndrome before the onset of the menopausal transition.

Cellular program controlling the recovery of adipose tissue mass: An in vivo imaging approach.

The cellular program responsible for the restoration of adipose tissue mass after weight loss is largely uncharacterized. Leptin mRNA levels are highly correlated with adipose tissue mass, and leptin expression can thus be used as a surrogate for changes in the amount of adipose tissue. To further study the responses of adipocytes to changes in weight, we created a transgenic mouse expressing the luciferase reporter gene under the control of leptin regulatory sequences, which allows noninvasive imaging of the leptin expression of mice in vivo. We used these animals to show that weight loss induced by fasting or leptin treatment results in the retention of lipid-depleted adipocytes in adipose depots. To further study the cellular response to weight regain after leptin treatment, a leptin withdrawal protocol was used to induce a state of acute leptin deficiency in wild type mice. Acute leptin deficiency led to the transient deposition of large amounts of glycogen within pre-existing, lipid-depleted adipocytes. This was followed by rapid reaccumulation of lipid. Transcriptional profiling revealed that this cellular response was associated with induction of mRNAs for the entire pathway of enzymes necessary to convert glucose into acetyl-CoA and glycerol, key substrates for the synthesis of triglycerides.

Krox20 stimulates adipogenesis via C/EBPbeta-dependent and -independent mechanisms.

Krox20 is a zinc finger-containing transcription factor that is abundantly expressed in adipose tissue. However, its role in fat cell differentiation has not been established. In cultured 3T3-L1 cells, Krox20 is rapidly induced by serum stimulation. Overexpression of Krox20 in both 3T3-L1 preadipocytes and multipotent NIH3T3 cells promotes adipogenesis in a hormone-dependent manner. Conversely, RNAi-mediated loss of Krox20 function reduced adipogenesis in 3T3-L1 cells. Ectopic expression of Krox20 can transactivate the C/EBPbeta promoter and increase C/EBPbeta gene expression in 3T3-L1 preadipocytes. RNAi-mediated knockdown of C/EPBbeta diminished Krox20's proadipogenic effect. Finally, coexpression of Krox20 and C/EBPbeta in naive NIH3T3 cells resulted in the pronounced induction of a fully differentiated adipocyte phenotype, an effect previously observed only with PPARgamma. These data indicate that Krox20 is necessary for adipogenesis and that, when overexpressed, Krox20 potently stimulates adipogenesis via C/EBPbeta-dependent and -independent mechanisms.

Correlates of circulating androgens in mid-life women: the study of women's health across the nation.

CONTEXT: Androgens influence sexual differentiation and behavior, body composition, and physical functioning in men, but their role in women is less well understood. Because circulating androgens decline with age, the use of androgen supplementation for women to improve health and well-being has been increasing. OBJECTIVE: The aim of this study was to assess the association between androgens and a variety of end points thought to be affected by androgens. DESIGN: In a community-based baseline cohort of women aged 42-52 yr from the Study of Women's Health Across the Nation, we measured circulating testosterone (T), dehydroepiandrosterone sulfate, and SHBG, and calculated a free androgen index (FAI) in 2961 women. MAIN OUTCOME MEASURES: Correlations of androgen measures with each other and with body mass index, waist circumference, and waist-hip ratio were computed, and odds ratios (OR) were estimated for the categorical outcomes of functional limitations, functional status, self-reported health, scores indicative of depressed mood, quality of life, sexual desire and arousal, and the presence of the metabolic syndrome. RESULTS: Androgens, and particularly SHBG, were associated most strongly with body mass index, waist circumference, and waist-hip ratio. SHBG was associated prominently inversely with the metabolic syndrome (OR = 0.32; 95% confidence interval = 0.26-0.39), which was present in 17% of women at baseline. Dehydroepiandrosterone sulfate was associated modestly with functional status and self-reported health. T was associated minimally with increased sexual desire (OR = 1.09; 95% confidence interval = 1.00-1.18). The association of FAI with self-reported health and depressive symptomatology based on the Center for Epidemiologic Studies Depression Scale score was explained more by T than by SHBG, whereas the association of FAI with sexual arousal and metabolic syndrome was due more to SHBG than to T. CONCLUSIONS: Circulating SHBG and androgens are most strongly associated with physical characteristics and the metabolic syndrome in women in this community-based cohort. Androgens are related weakly to physical functioning and other symptoms to which they commonly are attributed, such as sexual desire, sexual arousal, and well-being.

Sex-hormone-binding globulin and the free androgen index are related to cardiovascular risk factors in multiethnic premenopausal and perimenopausal women enrolled in the Study of Women Across the Nation (SWAN).

BACKGROUND: Recent clinical trials have shifted attention away from estrogens and toward androgens and sex hormone-binding globulin (SHBG) as potential mediators of increasing cardiovascular (CV) risk in women at midlife. METHODS AND RESULTS: The correlation between reproductive hormones and CV risk factors was evaluated in a multiethnic (white, black, Hispanic, Chinese, and Japanese) sample of 3297 premenopausal and perimenopausal women. Testosterone and estradiol (E2) were evaluated along with SHBG and the free androgen index (FAI), the amount of testosterone not bound by SHBG. Low SHBG and high FAI were strongly and consistently related to elevated CV risk factors (higher insulin, glucose, and hemostatic and inflammatory markers and adverse lipids) even after controlling for body mass index (P<0.001 for all). Low levels of E2 were associated with elevated CV risk factors to a lesser degree. These observations were consistent across the 5 ethnic groups. Compared with whites, blacks had higher levels of SHBG and lower levels of FAI, and Chinese had lower levels of SHBG and higher levels of FAI. CONCLUSIONS: Low SHBG and high FAI are strongly associated with CV risk factors in racially diverse women, and thus, androgens likely play a role in the CV risk profile of perimenopausal women.

Physical activity and diabetes risk in postmenopausal women.

BACKGROUND: To evaluate the hypothesis that physical activity independently predicts type 2 diabetes risk in postmenopausal African-American, Hispanic, Asian, and Caucasian women. METHODS: We prospectively evaluated the relationship between incident type 2 diabetes, walking, and total physical activity at baseline in the Women's Health Initiative Observational Study. Baseline data were collected between September 1994 and December 1998; incident diabetes was identified through August 2002. Hazard ratios for self-reported diabetes adjusted for body mass index (BMI) and other variables were evaluated across categories of physical activity in Caucasian, African-American, Hispanic, and Asian/Pacific Islander women. RESULTS: Incident diabetes was reported by 2.2% of Caucasian, 6.2% of African-American, 4.5% of Hispanic, 3% of Asian, and 5.7% of American Indian women (p <0.0001 across ethnic groups) during 458,018 woman-years of follow-up. Among Caucasian women, walking (multivariate-adjusted hazard ratios 1.00, 0.85, 0.87, 0.75, 0.74; p <0.001 for trend across exercise quintiles) and total physical activity score (hazard ratios 1.00, 0.88, 0.74, 0.80, 0.67; p =0.002) demonstrated a strong inverse relationship with diabetes risk. In BMI-adjusted models, African-American women in higher physical activity categories were less likely to develop diabetes than women in the lowest physical activity category. After adjusting for age and multiple risk factors, however, no significant association between physical activity and diabetes risk was apparent for African-American, Hispanic, or Asian women. CONCLUSIONS: These findings suggest a stronger and more independent association of physical inactivity with development of diabetes in Caucasian women than in minority women, but could also be explained by less precise risk estimates in minority women or the role of chance.

Depressive symptoms, insulin resistance, and risk of diabetes in women at midlife.

OBJECTIVE: To examine depression and 3-year change in insulin resistance and risk of diabetes and whether associations vary by race. RESEARCH DESIGN AND METHODS: We analyzed data from 2,662 Caucasian, African-American, Hispanic, Japanese-American, and Chinese-American women without a history of diabetes from the Study of Women's Health Across the Nation. We estimated regression coefficients and odds ratios to determine whether depression (Center for Epidemiological Studies Depression Scale score > or =16) predicted increases in homeostasis model assessment of insulin resistance (HOMA-IR) and greater risk of incident diabetes, respectively, over 3 years. RESULTS: Mean baseline HOMA-IR was 1.31 (SD 0.86) and increased 0.05 units per year for all women (P <0.0001). A total of 97 incident cases of diabetes occurred. Depression was associated with absolute levels of HOMA-IR (P <0.04) but was unrelated to changes in HOMA-IR; associations did not vary by race. The association between depression and HOMA-IR was eliminated after adjustment for central adiposity (P=0.85). Depression predicted a 1.66-fold greater risk of diabetes (P <0.03), which became nonsignificant after adjustment for central adiposity (P=0.12). We also observed a depression-by-race interaction (P <0.05) in analyses limited to Caucasians and African Americans, the only groups with enough diabetes cases to reliably test this interaction. Race-stratified models showed that depression predicted 2.56-fold greater risk of diabetes in African Americans only, after risk factor adjustment (P=0.008). CONCLUSIONS: Depression is associated with higher HOMA-IR values and incident diabetes in middle-aged women. These associations are mediated largely through central adiposity. However, African-American women with depression experience increased risk of diabetes independent of central adiposity and other risk factors.

Physical activity and changes in weight and waist circumference in midlife women: findings from the Study of Women's Health Across the Nation.

Controversy exists regarding the extent to which age, menopausal status, and/or lifestyle behaviors account for the increased weight, fat mass, and central adiposity experienced by midlife women. To address this question, the authors longitudinally examined the relations of aging, menopausal status, and physical activity to weight and waist circumference in 3,064 racially/ethnically diverse women aged 42-52 years at baseline who were participating in the Study of Women's Health Across the Nation (SWAN), an observational study of the menopausal transition. Over 3 years of follow-up (1996-1997 to 1999-2000), mean weight increased by 2.1 kg (standard deviation (SD), 4.8) or 3.0% (SD, 6.5) and mean waist circumference increased by 2.2 cm (SD, 5.4) or 2.8% (SD, 6.3). Change in menopausal status was not associated with weight gain or significantly associated with increases in waist circumference. A one-unit increase in reported level of sports/exercise (on a scale of 1-5) was longitudinally related to decreases of 0.32 kg in weight (p < 0.0001) and 0.10 cm in waist circumference (not significant). Similar inverse relations were observed for daily routine physical activity (biking and walking for transportation and less television viewing). These findings suggest that, although midlife women tend to experience increases in weight and waist circumference over time, maintaining or increasing participation in regular physical activity contributes to prevention or attenuation of those gains.

Ethnic differences in insulin sensitivity and beta-cell function in premenopausal or early perimenopausal women without diabetes: the Study of Women's Health Across the Nation (SWAN).

OBJECTIVE: To assess differences in insulin sensitivity and beta-cell function between nondiabetic premenopausal or early perimenopausal non-Hispanic white women and African American, Chinese American, Japanese American, and non-Mexican-American Latino women. RESEARCH DESIGN AND METHODS: Homeostasis model assessments (HOMAs) of insulin sensitivity (HOMA%S) and beta-cell function (HOMA%beta) were used. Stepwise multivariable ethnic-specific ANCOVA models were used to compare HOMA%S and HOMA%beta between non-Hispanic whites and each of the four ethnic groups. RESULTS: HOMA%S was lower in African Americans, Chinese Americans, and Japanese Americans when compared with non-Hispanic white women after correcting for waist circumference, presence of impaired fasting glucose, and site. Significant differences persisted only between African Americans and non-Hispanic whites after inclusion of triglycerides in the model. Triglycerides indirectly corrected for the differences in HOMA%S in the other two groups. There were no differences in HOMA%S between the non-Mexican-American Latinos and the non-Hispanic whites. Japanese Americans and Chinese Americans had lower HOMA%beta than non-Hispanic whites, whereas African Americans had higher HOMA%beta than non-Hispanic whites after correcting for confounders. HOMA%beta was similar between non-Mexican-American Latinos and non-Hispanic whites. CONCLUSIONS: These data suggest that type 2 diabetes prevention strategies for African-American women should initially target decreased insulin sensitivity, whereas strategies for Japanese-American and Chinese-American women may initially need to target both decreased insulin sensitivity and beta-cell function. Previous studies of Mexican-American populations may not apply to non-Mexican-American Latino women.

Insulin resistance, hemostatic factors, and hormone interactions in pre- and perimenopausal women: SWAN.

We evaluated the association of hemostatic factors with insulin resistance in relation to reproductive hormones including FSH, estradiol, testosterone, and SHBG. SHBG was used to calculate the free estradiol index and free androgen index. We studied 3,200 women, aged 42-52 yr, in the Study of Women's Health Across the Nation, a prospective multiethnic study of the menopausal transition. We measured the hemostatic factors, fibrinogen, factor VIIc, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor type 1 (PAI-1), as well as glucose and insulin to calculate insulin resistance. After adjustment for body mass index, site, and ethnicity, SHBG was correlated with PAI-1 (partial r = -0.30) and t-PA (partial r = -0.12). Although testosterone was associated with t-PA (partial r = 0.13) and PAI-1 (partial r = 0.07), free androgen index was strongly correlated with t-PA (partial r = 0.18) and PAI-1 (partial r = 0.26). SHBG modified the association of hemostatic factors with insulin resistance. Women with greater insulin resistance had lower SHBG and higher PAI-1. Estrogen measures were not associated with insulin resistance. The influence of sex hormones on hemostatic factors and insulin resistance is poorly understood. SHBG, which influences the amount of bioavailable hormone, significantly modified the association of PAI-1 and t-PA with insulin resistance. The longitudinal Study of Women's Health Across the Nation will help us discern whether this interaction contributes to heart disease and diabetes among postmenopausal women.