Why do bees turn back and look?

The timing of learning of colour and shape of the food source, as well as of near-by landmarks, was examined exploiting a behaviour described recently, the Turn Back and Look behaviour (TBL): Bees departing from a novel food source after feeding turn around to view it at a short distance (Figs. 2, 3) before departing for the hive. They repeat this behaviour on several successive visits, termed the TBL phase (Fig. 5). To examine the function of the TBL, I trained individual bees in 4 different modes. In the first 3 they could view a food source or a landmark of a particular colour or shape during (i) arrival as well as departure, (ii) only arrival, and (iii) only departure; in the final mode (iv) the bees viewed one colour (or shape) on arrival, and another on departure. At the end of the TBL phase, the bees were tested by offering them a choice between the visual stimulus to which they were trained (modes i–iii) and a different (novel) one, or between the stimulus viewed on arrival and that viewed on departure (mode iv). The test results show that learning after feeding (while performing the TBL), i.e. backward conditioning, occurs regardless of whether the colour (Fig. 6, Fig. 10a) or shape (Fig. 7) of the food source, or the colour (Fig. 10b), shape (Fig. 11), and position (Fig. 12) of a near-by landmark is considered. Bees trained in mode (iv) preferred the stimulus learned on arrival over that learned on departure in almost all cases. However, a stimulus viewed exclusively on departure (mode iii) was often learned as well as when it was viewed exclusively on arrival (mode ii) (Figs. 10a, 11, 12), or both on arrival and departure (mode i) (Fig. 6). The finding that the timing of learning can be manipulated suggests that it is not based on hard wired predispositions to learn particular visual cues on arrival, and others on departure.     

Correlates of health-related quality of life in overweight and obese adults with type 2 diabetes

Objective: This paper describes and examines conceptually relevant correlates of health‐related quality of life (HRQL) in overweight or obese persons with type 2 diabetes. Research Design and Procedures: The investigation was a cross‐sectional study of 5145 overweight or obese adults with type 2 diabetes between the ages of 45 and 74 years. Analyses examined the relationship that demographic characteristics, disease burden, and cardiovascular fitness had with HRQL: the Short Form 36 (SF‐36) and the Beck Depression Inventory (BDI) II. Results: Means for the SF‐36 physical component summary (PCS) scores, the mental component summary scores, and the BDI‐II were as follows: 47.0, 54.0, and 5.7. Less desirable PCS scores were related to several comorbidities, insulin use, physical complaints, a high BMI, low metabolic equivalent (MET) capacity, and lower education. Interactions between categories of obesity and MET capacity revealed that greater BMI was related to lower PCS scores when individuals had lower MET capacities yet was absent for those individuals who had higher MET capacities. In addition, although greater BMI was associated with more severe depressive symptomatology, this association was the most dramatic for those with class III obesity who had low MET capacity. Discussion: Although participants in Look AHEAD had a favorable profile on the SF‐36 and the BDI‐II at baseline, lower PCS scores were related to disease severity and the presence of other comorbidities. More important, although the temporal ordering of associations cannot be determined in a cross‐sectional design, the interactions between obesity class and MET capacity suggest that the adverse effect of BMI on PCS and BDI‐II scores may be buffered by higher MET capacities.