Activity patterns of Queensland fruit flies (Bactrocera tryoni) are affected by both mass‐rearing and sterilization

Mass‐reared sterile tephritid flies released in sterile insect technique (SIT) programmes exhibit behaviour, physiology and longevity that often differ from their wild counterparts. In the present study, video recordings of flies in laboratory cages are used to determine whether the sequential processes of mass‐rearing and sterilization (using gamma radiation) that are integral to SIT affect general activity patterns of male and female Queensland fruit flies Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) (‘Q‐flies'). Compared with wild flies, mass‐reared flies exhibit a marked reduction in overall activity, and further reduction is found after sterilization. In terms of the frequency of activities, both fertile and sterile mass‐reared Q‐flies fly less often and exhibit more bouts of inactivity and grooming than wild Q‐flies. In addition, in terms of the duration of activities, fertile and sterile mass‐reared Q‐flies spend less time flying and more time walking, grooming and being inactive than wild Q‐flies. Although fertile and sterile mass‐reared flies are similar in other regards, sterile mass‐reared flies spend more time being inactive than fertile mass‐reared flies. These findings raise new questions about how changes in behaviour and activity levels may influence the performance of mass‐reared sterile Q‐flies in the field, as well as the physiological and metabolic processes that are involved. The frequency and duration of inactivity could provide a simple but powerful and biologically relevant test for quality in mass‐rearing and SIT programs.     

Neurotrophins improve synaptic transmission in the adult rodent diaphragm

Neurotrophins are usually viewed as secreted proteins that control long-term survival and differentiation of neurons. However, recent studies have established that among the most important functions of neurotrophins is their capacity to regulate synaptic functions and plasticity. When altering synaptic function, neurotrophins are able to produce two types of outcomes, an immediate effect on synaptic transmission and long-term control of synaptic structure and function. The first effect occurs within seconds or minutes after the neurotrophic factor has been applied and usually involves acute modification of synaptic transmission. The second effect takes hours and days, as protein synthesis is required to complete the structural changes. Neurotrophins and their receptors are expressed within the neuromuscular system, making these agents ideal candidates for the short-and long-term regulation of skeletal muscle function. For instance, neurotrophins can alter neuromuscular function acutely, by modulating the amount of neurotransmitter released with each nerve impulse, or chronically, by changing postsynaptic properties or the content and size of synaptic vesicles. It is obvious that the effects of neurotrophins depend on the specific neurotrophin involved (four neurotrophins have been found in mammals; these are nerve growth factor, brain-derived neurotrophic factor, and neurotrophins-3 and-4) and on the specific synapse being studied. Growing evidence highlights the role of neurotrophins in the development and function of neuromuscular synapses. This review will examine the role of neurotrophins in the regulation of neuromuscular transmission. Neirofiziologiya/Neurophysiology, Vol. 39, Nos. 4/5, pp. 327–337, July–October, 2007.     

Understanding oral stereotypies in calves: alternative strategies,hypothalamic–pituitary–adrenal axis (re)activity and gene by environment interactions

Stereotypies are used as indicators of poor animal welfare and it is, therefore, important to understand underlying factors mediating their development. In calves, two oral stereotypies, that is, tongue playing and object manipulation, result mostly from insufficient structure in the diet. Three hypotheses were studied: (1) oral stereotypies in calves are one of two alternative strategies, the alternative being hypo-activity; (2) stereotyping and non-stereotyping calves differ in terms of cortisol secretion; (3) oral stereotypy development in calves rests on a gene by environment interaction. Eight-week-old bull calves (n=48) were assigned to one of four solid feed allowances (0, 9, 18 or 27 g dry matter/kg metabolic weight per day) with the following composition: 50% concentrate, 25% maize silage and 25% straw on dry matter basis. The calves received milk replacer in buckets, the provision of which was adjusted to achieve equal growth rates. At 14 to 18 weeks of age, calves were exposed to a challenge, that is, tethering inside cages. Oral stereotypies and inactivity were recorded in the home pens in the 4 weeks before the challenge using instantaneous scan sampling. Salivary cortisol levels were measured at −120, +40, +80, +120 min and +48 h relative to the challenge. Individual differences in behaviour were recorded in the first 30 min after challenge implementation using focal animal sampling and continuous recording, and these elements were entered into a principal component (PC) analysis to extract PCs. Regression analyses were performed to find relationships between stereotypies and inactivity, stereotypies and cortisol, and stereotypies and PCs (individual differences, genes) and solid feed (environment). Relationships between PCs and cortisol were also investigated to help with the interpretation of PCs. Hypotheses 1 and 2 were rejected. Hypothesis 3, however, was supported: calves with a zero solid feed allowance, that is, in the most barren environment, showed links between stereotypies and two of the PCs. Calves that displayed high levels of idle and rapid locomotion and low levels of oral contact with the cage during the challenge also displayed high levels of object manipulation in the home pens. Calves that displayed low levels of stepping and turning attempts during the challenge also displayed high levels of tongue playing in the home pens. This study corroborates the gene by environment interaction on the development of oral stereotypies in calves.     

Parental Weight Status and Girls’ Television Viewing,Snacking, and Body Mass Indexes

Objective: The purpose of this study was to examine whether television viewing (TVV) provides a context for patterns of snacking fostering overweight in young girls from overweight and non‐overweight families. Research Methods and Procedures: Participants were 173 non‐Hispanic white girls and their parents from central Pennsylvania, assessed longitudinally when girls were 5, 7, and 9 years old. Path analysis was used to test patterns of relationships among girls’ TVV, snacking while watching television, snacking frequency, fat intake from energy‐dense snack food, and girls’ increase in body mass index (BMI) from age 5 to 9. Results: In both overweight and non‐overweight families, girls who watched more television consumed more snacks in front of the television. In families where neither parent was overweight, television viewing was the only significant predictor of girls’ increase in BMI. In families where one or both parents were overweight, girls who watched more television snacked more frequently, and girls who snacked more frequently had higher intakes of fat from energy‐dense snacks, which predicted their increase in BMI from age 5 to 9. TVV did not directly predict girls’ increase in BMI in girls from overweight families. Discussion: The results of this study support and extend previous findings that have shown that excessive television viewing and snacking patterns are risk factors for the development of overweight in children; however, patterns of relationships may differ based on parental weight status. For overweight families, TVV may provide a context for excessive snack consumption, in addition to inactivity.     

An Evolutionary Perspective on Sedentary Behavior

Most people are aware of the health benefits of being physically active. The question arises then why people so easily fall into sedentary habits. The idea developed here is that sedentary behavior is part of a suite of behaviors to reduce levels of physical activity that were strongly selected in the evolutionary past, likely because high levels of physical activity had direct negative consequences for survival. However, hunter-gatherer populations could not reduce activity indefinitely because of the need to be active to hunt for, and gather food. Hence they never experienced low levels of activity that are damaging to health, and no corresponding mechanism avoiding low activity evolved. Consequently, gene variants promoting efficiency of activity and increased sedentariness were never selected against. Modern society facilitates reduced activity by providing many options to become less active and divorcing food intake from the need to be active. Choosing the less active option is hard wired in the genes; this explains why being sedentary is so common, and why reversing it is so difficult. Incentivizing activity may be enabled using modern technology, but ultimately may only end up replacing one set of health issues with others. Also see the video abstract here https://youtu.be/ekHbUwPw-v4 .     

Applications of proportional odds ordinal logistic regression models and continuation ratio models in examining the association of physical inactivity with erectile dysfunction among type 2 diabetic patients

[Purpose]Many studies have observed a high prevalence of erectile dysfunction among individuals performing physical activity in less leisure-time. However, this relationship in patients with type 2 diabetic patients is not well studied. In exposure outcome studies with ordinal outcome variables, investigators often try to make the outcome variable dichotomous and lose information by collapsing categories. Several statistical models have been developed to make full use of all information in ordinal response data, but they have not been widely used in public health research. In this paper, we discuss the application of two statistical models to determine the association of physical inactivity with erectile dysfunction among patients with type 2 diabetes.[Methods]A total of 204 married men aged 20-60 years with a diagnosis of type 2 diabetes at the outpatient unit of the Department of Endocrinology at PSG hospitals during the months of May and June 2019 were studied. We examined the association between physical inactivity and erectile dysfunction using proportional odds ordinal logistic regression models and continuation ratio models.[Results]The proportional odds model revealed that patients with diabetes who perform leisure time physical activity for over 40 minutes per day have reduced odds of erectile dysfunction (odds ratio=0.38) across the severity categories of erectile dysfunction after adjusting for age and duration of diabetes.[Conclusion]The present study suggests that physical inactivity has a negative impact on erectile function. We observed that the simple logistic regression model had only 75% efficiency compared to the proportional odds model used here; hence, more valid estimates were obtained here.     

Sugar feeding reduces short-term activity of a parasitoid wasp

Abstract.  Adding sugar to agricultural habitats is expected to enhance pest control by improving the longevity and physiological status of parasitoids. How a sugar diet and physiological parameters affect the host-foraging behaviour of Diadegma insulare , a parasitoid of diamondback moth larvae ( Plutella xylostella ), is investigated in the laboratory. Newly-emerged females are given water or sucrose-water ad libitum for 1 day, and then monitored for movement onto and away from a single cabbage leaf infested with 30 host larvae for 1 h. A significantly lower percentage of sucrose-fed females enter the host patch than those with access to only water (starved) females (60% vs. 91%). Of the females that enter the patch, fed wasps spend significantly less time in the patch than starved wasps (32.2 vs. 25.7 min) but feeding does not significantly affect oviposition rate. Fed and starved females sting six to seven larvae, and 19–29% of females superparasitize host larvae. Wasps with higher levels of fructose are less likely to enter the host patch than wasps with lower fructose levels. The lower proportion of fed wasps entering the patch may be due to a period of inactivity after sugar feeding.     

Age‐related activity patterns are moderated by diet in Queensland fruit flies Bactrocera tryoni

Life‐history parameters and the fitness of tephritid flies are closely linked to diet. Studies of locomotor behaviour can provide insights to these links, although little is known about how locomotor behaviour is influenced by diet. In the present study, video recordings of Queensland fruit flies Bactrocera tryoni Froggatt (Diptera: Tephritidae) (‘Q‐flies’) that are maintained individually in cages are used to determine how diet affects the activity patterns (flight, walking, grooming, inactivity) of males and females at ages ranging from 4 to 30 days. The frequency and total duration of activities over 10‐min trials are affected by diet, age and sex. Supplementation of diet with hydrolysed yeast results in a higher frequency and duration of flight in flies of all ages and both sexes. The effect of diet on other activities varies with age. Q‐flies fed sugar only increase walking frequency steadily from 4 to 30 days post‐eclosion, whereas flies fed sugar + yeast have higher walking frequencies at 4 and 10 days than flies fed sugar only, although they then exhibit a sharp decline at 30 days post‐eclosion. The frequency and duration of inactivity remain consistent in flies fed sugar + yeast, whereas flies fed sugar only exhibit a marked increase in inactivity from 4 to 30 days post‐eclosion. Compared with older flies, 4 day‐old Q‐flies fed sugar only spend considerably more time grooming. The potential of activity monitoring as a quality control test for flies that are mass‐reared for use in sterile insect technique programmes is discussed.     

圈养亚洲象尿液中雌二醇和孕酮含量的周期性变化

针对北京动物园2头圈养雌性亚洲象从未动情的现象,本研究于2003年12月至2005年3月,采用放射性免疫分析法测定了2只不动情象与另一只已受孕象尿液中孕酮和雌二醇的变化,并结合国内外研究探讨圈养亚洲象不动情的原因,为圈养象机构提供相应的繁殖管理建议。研究结果表明,受孕雌象在分娩前一周左右孕酮含量突然升高,后在很短时间内降低,分娩后也维持在较低水平;雌二醇含量分娩前维持在较高水平,分娩前一周骤降,并保持较低水平至本研究结束。非动情象尿液中孕酮和雌二醇水平都显著低于受孕象相应的激素水平,且无明显的波动,推测其卵巢不具活性,导致孕酮与雌二醇水平不具波动性,是这2头圈养雌象未见动情现象的主要原因。     

An Objective Method for Measurement of Sedentary Behavior in 3‐ to 4‐Year Olds

Objective: To test the ability of accelerometry to quantify sedentary behavior in 3‐ to 4‐year‐old children. Research Methods and Procedures: We developed a cut‐off for accelerometry output (validation study) in 30 healthy 3 to 4 year olds, which provided highest sensitivity and specificity for the detection of sedentary behavior relative to a criterion method of measurement, direct observation using the children's physical activity form. We then cross‐validated the cut‐off in an independent sample of healthy 3 to 4 year olds (n = 52). Results: In the validation study, optimal sensitivity and specificity for the detection of sedentary behavior were obtained at an accelerometry output cut‐off of <1100 counts/min. In the cross‐validation, sensitivity was 83%: 438/528 inactive minutes were correctly classified. Specificity was 82%: 1251/1526 noninactive minutes were correctly classified using this cut‐off. Discussion: Sedentary behavior can be quantified objectively in young children using accelerometry. This new technique could be considered for a wide variety of applications in the etiology, prevention, and treatment of childhood obesity.