Sexual Dimorphism of Brown Adipose Tissue Function.

OBJECTIVE: To determine whether brown adipose tissue (BAT) activity in school-age children differs between the sexes and to explore the impact of dietary intake, sedentary behavior, and picky/fussy eating. STUDY DESIGN: Children aged 8.5-11.8 years of age (n = 36) underwent infrared thermography to determine the temperature of the skin overlying the main superficial BAT depot in the supraclavicular region before and after 5 minutes of mild cold exposure (single-hand immersion in cool tap water at about 20°C). The relationships between the supraclavicular region temperature and parental reports of food consumption, eating behavior, and inactivity were explored. RESULTS: The supraclavicular region temperature was higher in boys (n = 16) at baseline, and after cold exposure. Boys displayed a greater thermogenic response to cold. Strong negative correlations were observed between the supraclavicular region temperature and body mass index percentile, and differences in supraclavicular region temperature between girls and boys persisted after adjustment for body mass index percentile. A negative linear relationship was observed between protein and vegetable intake and supraclavicular region temperature in girls only, but did not persist after adjustment for multiple comparisons. There was no difference in the adjusted supraclavicular region temperature between active or inactive children, or picky and nonpicky eaters. CONCLUSIONS: These findings indicate sexual dimorphism in BAT thermogenic activity and a sex-specific impact of diet. Future studies should aim to quantify the contribution of BAT to childhood energy expenditure, energy imbalance, and any role in the origins of childhood obesity.

Evaluating the Performance and Preference of Aphytis melinus (Hymenoptera: Aphelinidae) on an Exotic Species, Acutaspis albopicta (Hemiptera: Diaspididae), and Aonidiella aurantii (Hemiptera: Diaspididae).

Acutaspis albopicta (Cockerell) is an exotic scale detected on imported 'Hass' avocados arriving in California from Mexico. An effort was made to understand how well this species might be biologically controlled by the parasitoid, Aphytis melinus DeBach. In no-choice trials, single life stages of A. albopicta and Aonidiella aurantii (Maskell) were exposed to one Ap. melinus female. Ap. melinus attacked and developed to adult on all A. albopicta life stages tested, which included early, middle, and late male and female second instars, and early, middle, and late female third instars. However, the proportion of scales attacked was relatively low (≤20%), as were the number of eggs laid on each scale stage. In six of seven comparisons of scale cover surface area between A. albopicta and Ao. aurantii that were similarly aged, Ao. aurantii was significantly larger. With intraspecific choice trials, females of Ap. melinus strongly preferred to parasitize the oldest and largest female scales in both single- and mixed-sex offerings. Younger, smaller scales were preferred for host feeding. Five comparisons of preference between A. albopicta and Ao. aurantii showed that Ap. melinus preferred 28- and 36-d-old Ao. aurantii females over similarly aged A. albopicta. However, Ap. melinus preferred 23-d-old males of A. albopicta. In three of five comparisons, Ao. aurantii was the preferred species to host feed on. More F1 females of Ap. melinus were recovered from both intraspecific choice trials compared with any stage in no-choice trials. Implications of incorporating Ap. melinus into biological control programs are discussed.

Body mass index as a determinant of brown adipose tissue function in healthy children.

OBJECTIVE: To determine whether body mass index (BMI) percentile and ethnicity influence skin temperature overlying brown adipose tissue (BAT) depots in the supraclavicular region in healthy children. STUDY DESIGN: Infrared thermography measured supraclavicular region temperature (T(SCR)) at baseline and after exposure to a mild cool stimulus (single hand immersion in water at 20.1 °C) for 5 minutes in children aged 6-11 years (n = 55). The studies were undertaken in a normal school environment. RESULTS: BMI percentile and ethnicity were significant predictors of baseline T(SCR), with an inverse relationship between BMI percentile persisting after adjustment for ethnicity. Twenty-four children demonstrated a significant rise in T(SCR) after exposure to the cool stimulus. BMI percentile was a significant predictor of T(SCR) response, although there was no effect of ethnicity on T(SCR) change after exposure to the cool stimulus. CONCLUSION: We have demonstrated a negative relationship between BMI percentile and both baseline T(SCR), colocating with the primary region of BAT, and the change in T(SCR) in response to the cool stimulus. Future studies aimed at determining the primary factors regulating BAT function in healthy children should be targeted at the goal of maintaining a healthy BMI trajectory during childhood.

Identification of the sex pheromone of the invasive scale Acutaspis albopicta (Hemiptera: Diaspididae), arriving in California on shipments of avocados from Mexico.

As a result of relaxation of importation restrictions ordered by the Animal and Plant Health Inspection Service of the U.S. Department of Agriculture, shipments of fresh avocados from Mexico began entering California year-round in 2007, despite the fact that these shipments were heavily infested with a number of exotic and potentially invasive armored scale species that are not thought to be present in California. Here, we report the identification of the sex pheromone of one of these species, Acutaspis albopicta (Cockerell), from a quarantine colony of these insects initiated from specimens collected from commercial shipments of Mexican avocados. The compound was identified as [(1S,3S)-2,2-dimethyl-3-(prop-1-en-2-yl)cyclobutyl)]methyl (R)-2-methylbutanoate, and was similar in structure to the pheromones of several other scale and mealybug species. In laboratory bioassays, the pheromone was highly attractive to male scales in microgram doses. The pheromone will provide a very sensitive and selective tool for detection of the scale to try and prevent its permanent establishment in California.