Production of Sexuals and Mating Frequency in the Stingless Bee Tetragonisca angustula (Latreille) (Hymenoptera, Apidae).

Queen, worker, and male production was studied for 1 year in three queenright colonies of Tetragonisca angustula (Latreille). We sampled brood combs monthly and noticed that the number of brood cells and production of individuals were similar among colonies. Although the production of queens did not vary significantly, the frequencies of workers, males, and the number of cells among the combs varied over time. The production of males was highly seasonal, occurring mostly from February to April, coinciding with the period of intense brood cells production, when colonies produced more males and less workers, resulting in a negative correlation. Although the frequency of queens has not varied in time, the seasonal availability of males affected the mating frequency and the time spent since emergence until fertilization of queens. In the T. angustula colonies studied, the population dynamics was highly seasonal and the mating success depended of male production, according to the season.

Esophageal motor abnormalities in children with gastroesophageal reflux and peptic esophagitis.

Esophageal motility was studied in 26 children with gastroesophageal reflux. In 11 patients (group A), esophagitis was severe; in the remaining 15 (group B), either mild or no microscopic changes were found. Lower esophageal sphincter pressure and amplitude, as well as velocity and duration of esophageal pressure waves, were manometrically measured. All patients underwent a 12-week intensive antacid course. Manometric tracings, blindly read, were compared with those of 16 age-matched children with emesis without proven reflux (group C). Among the variables analyzed, amplitude of the motor waves was significantly lower in patients with severe esophagitis than in group B and C patients (P less than 0.01). Nonspecific motor defects (simultaneous, broad-based, double-peaked waves) were more commonly present in group A. At the end of therapy, symptoms had either disappeared or significantly improved. Endoscopic and histologic studies showed disappearance of the severe inflammatory changes. Manometry, repeated in patients with cured severe esophagitis, showed normalization of the amplitude and significant decrease of the nonspecific motility abnormalities. We conclude that severe gastroesophageal reflux disease in children causes esophageal motor dysfunction, resulting from esophageal inflammation. The occurrence of esophageal motility disorders only in patients with severe esophagitis and its disappearance after therapy may account for the favorable course of reflux disease in infancy.