Anatomical, phenological and genetic aspects of the host-parasite relationship between Andrena vaga (Hymenoptera) and Stylops ater (Strepsiptera)

Stylops ater is an endoparasite of the mining bee Andrena vaga with extreme sexual dimorphism and hypermetamorphosis. Its population structure, parasitization mode, genetic diversity and impact on host morphology were examined in nesting sites in Germany to better understand this highly specialized host–parasite interaction. The shift in host emergence due to stylopization was proven to be especially strong in A. vaga. Around 10% of bees hosted more than 1 Stylops, with at maximum 4. A trend in Stylops' preference for hosts of their own sex and a sex-specific position of extrusion from the host abdomen was found. Invasion of Andrena eggs by Stylops primary larvae was depicted for the first time. Cephalothoraces of female Stylops were smaller in male and pluristylopized hosts, likely due to lower nutrient supply. The genes H3, 18S and cytochrome c oxidase subunit 1 were highly conserved, revealing near-absence of local variation within Stylops. Ovaries of hosts with male Stylops contained poorly developed eggs while those of hosts with female Stylops were devoid of visible eggs, which might be due to a higher protein demand of female Stylops. Male Stylops, which might have a more energy-consuming development, led to a reduction in head width of their hosts. Host masculinization was present in the leaner shape of the metabasitarsus of stylopized females and is interpreted as a by-product of manipulation of the host's endocrine system to shift its emergence. Stylopization intensified tergal hairiness, most strongly in hosts with female Stylops, near the point of parasite extrusion, hinting towards substance-induced host manipulation.

[Anorexia nervosa--the triad of metric index, BMI age-specific percentile curve and goal weight]

Cross sectional and longitudinal data from the Berlin Anorexia Study on the inpatient treatment of n = 133 adolescent females with the principal axis I diagnosis of an eating disorder (n = 104 anorexia nervosa, n = 19 bulimia nervosa, n = 10 eating disorders not otherwise specified; according to ICD-10 and DSM-IV criteria) indicate a significant shift in the frequency distribution of somatometrically assessed types of body shape among patients as categorized by the Metric Index, towards the leptomorphic phenotype (p < 0.050, chi 2/Fisher's). Three explanatory models are discussed. Diagnostic and therapeutic implications, particularly of the determination of target weight in anorexia nervosa based on the individual's type of body shape, are emphasized, and an operational algorithm is proposed which uses the Metric Index and sex-specific BMI age percentiles adjusted for type of body shape.

Anorexia nervosa - Die Trias von Metrik-Index, BMI-Altersperzentilenkurve und Zielgewicht

Zusammenfassung: Anhand von n = 133 adoleszenten Patientinnen der Berliner Anorexie-Studie belegen Quer- und Längsschnittdaten der stationären Therapie bei Anorexia nervosa (n = 104; Achse-I-Hauptdiagnose nach ICD-10 und DSM-IV-Kriterien), Bulimia nervosa (n = 19) und atypischen Eßstörungen (n = 10) eine signifikante Verschiebung der nach dem Metrik-Index kategorisierten typologischen Häufigkeitsverteilung in Richtung leptomorpher Körperbauvarianten (p < 0.050, χ2/Fisher's). Drei Erklärungsmodelle werden diskutiert. Es wird auf die diagnostische und therapeutische Bedeutung eingegangen, insbesondere für eine körperbautypgerechte Zielgewichtsbestimmung bei Anorexia nervosa. Ein entsprechender Algorithmus unter Nutzung von Metrix-Index und geschlechtsspezifischen BMI-Altersperzentilen wird vorgeschlagen.

Physique and body composition: comparisons of methods and results

Body mass is the most investigated measurement for the evaluation of the nutritional and health status of children and adults. To apply it requires consideration of its correlations with sex, height and age, and if possible the type of body shape. It requires also the consideration of body composition, in particular the total body fat content. Here a problem arises. While classic anthropometric techniques are suitable for field investigations with large samples, the investigation of body composition needs the highly technical equipment of a laboratory as a rule. Based on a representative sample of 21,648 males and 21,391 females from all the new federal states of Germany this paper tries to find easily obtained anthropometric measurements which are usable for a type specific estimation of body composition under field conditions. For this reason body mass by sex and height is classified by three different concepts: the skeletal concept with categories of frame size, estimated by the frame index, the whole body concept with categories of corpulence, estimated by the metric index, and the fat concept with categories of subcutaneous fat layer thicknesses. Focussing on a type-specific body mass by height for an assessment of the nutritional status, the skeletal concept is proved to be the best. The summary of body mass and height by the body mass index (BMI), measured in kg/m2, gives the possibility of bringing two measurements into one dimension and to leave the second dimension free for the important variable of age. BMI by sex, age and frame type is found to be a good and practical instrument for the assessment of the nutritional and health status.

[Normal weight and optimal weight--description and evaluation of body mass]

In this paper body mass and body mass in relation to height is analyzed, based on a cross-sectional sample of 21,648 boys and men, and 21,391 girls and women living in villages, towns, and cities in all new federal states of Germany. The sample is stratified to sex, age, territory and size of the settlement. Weight to height regression lines are compared to the results of weight categories by height. The results of the normal weight categories are compared to the optimal weights of Broca, Ott, and Möhr as well as to the standard weights of the US-population. It is pointed out that body mass does not only depend on age and type of body shape during growth age, but also during adulthood. Curves of normal weight are given for children and adolescents in relation to their sex, age, height, and type of body shape. The median values of weight are published as tables for adults.

Body composition, nutrition and nutritional habits of young and elderly adults

After the unification of East and West Germany the living conditions and the nutritional habits of the East German population changed considerably. The effects of these changes on nutritional status, physique and body composition are examined by a comparison of the representative sample of Greil taken from the East German population before the reunification of Germany with the sample of Trippo measured in the East German town of Potsdam between 1995 and 1997. The comparison of the samples of Greil and Trippo gives no indication of any increase in overweight subjects or adiposity during the last few years amongst the older test persons. However, the body mass of younger subjects shows a slight increase. Comparison of the estimates of total body fat showed considerable variation in results for skinfold thickness measurements and bioelectrical impedance analysis depending on the formula used.

Ontogenetic aspects of dimensions and proportions in sitting posture

Dimensions and proportions of the human body in sitting posture are ergonomical important, because our body is supported by seats every day from early infancy to old age. Based on a stratified sample of 42,000 persons, aged from birth to 70 years, and living in German cities, town and villages, reference values of trunk-cephalic height, trunk length, physiognomic leg length, and additive arm length are presented in relation to sex and age. The proportions of these basic measurements to height are given additionally as well as the intermembral-index (100 x additive arm length/physiognomic leg length) and the scelic index (100 x physiognomic leg length/trunk length). The different average velocity of the bodily development among both sexes is analysed and discussed. The second part of the article is dedicated to the important question of the variability of measurements in sitting posture during adulthood. Percentiles of trunk-cephalic height, trunk length, depth of the lower trunk, maximum sitting breadth, vertical thigh diameter, lower leg and foot length, backrest-heel distance, and additive arm length are presented by sex, age and type of body shape.