Neuroactive hormones and interpersonal trust: International evidence

Social attachment is vital for human health and welfare. Recent experimental evidence in humans has identified the role of neuroactive hormones, especially the peptide oxytocin, in mediating trusting behaviors. Herein, we test if the endocrinological basis for trust between humans scales up to the country level. Trust pervades nearly every aspect of our daily lives, yet survey data on trust show substantial variation across countries. Using 31 measures of biological, social, and environmental factors associated with hormone levels for a sample of 41 countries, we find that two classes of factors are related to trust: consumption of plant-based estrogens (phytoestrogens), and the presence of environmental conditions that include measures of estrogen-like molecules. Our findings provide preliminary evidence that interpersonal trust at the country level may be related to the intake of neuroactive hormones.     

Behavioral responses of red hake,Urophycis chuss,to decreasing concentrations of dissolved oxygen

Synopsis Laboratory experiments were conducted to examine changes in behavior of red hake,Urophycis chuss, under decreasing concentrations of dissolved oxygen (DO). Since the ecological requirements of this species change with age, responses were measured for three different groups: (1) age 0+, = 89 mm total length (TL); (2) age 1+, = 238 mm TL; and (3) age 2–3+, = 397 mm TL. As DO decreased from 8–10 mg l^-1 to < 0.5 mg l^-1, changes were evident in active time, water column activity, range of horizontal movement, food searching, and agonistic behavior. Age 0+ fish were most sensitive, moving up into the water column and swimming continuously as DO levels fell below 4.2 mg l^-1. Age 2–3+ fish were the least responsive, remaining on the substrate and increasing only their range of movement at concentrations below 3 mg l^-1. Responses of age 1 + fish were variable, possibly reflecting a transition stage between the younger and older fish. Common to all groups was the decrease and eventual cessation of food searching.     

Reduction of predation risk under the cover of darkness: Avoidance responses of mayfly larvae to a benthic fish

Summary Mayfly larvae of Paraleptophlebia heteronea (McDunnough) had two antipredator responses to a nocturnal fish predator (Rhinichthys cataractae (Valenciennes)): flight into the drift and retreat into interstitial crevices. Drift rates of Paraleptophlebia abruptly increased by 30 fold when fish were actively foraging in the laboratory streams but, even before fish were removed, drift began returning to control levels because larvae settled to the substrate and moved to areas of low risk beneath stones. This drifting response was used as an immediate escape behavior which likely decreases risk of capture from predators which forage actively at night. Surprisingly, drift most often occurred before contact between predator and prey, and we suggest that in darkness this mayfly may use hydrodynamic pressure waves for predator detection, rather than chemical cues, since fish forage in an upstream direction. Although drifting may represent a cost to mayfly larvae in terms of relocation to a new foraging area with unknown food resources, the immediate mortality risk probably out-weighs the importance of staying within a profitable food patch because larvae can survive starvation for at least 2 d. In addition to drifting, mayflies retreated from upper, exposed substrate surfaces to concealed interstitial crevices immediately after a predator encounter, or subsequent to resettlement on the substrate after predator-induced drift. A latency period was associated with this response and mayflies remained in these concealed locations for at least 3 h after dace foraging ceased. Because this mayfly feeds at night and food levels are significantly lower in field refugia under stones, relative to exposed stone surfaces, predator avoidance activity may limit foraging time and, ultimately, reduce the food intake of this stream mayfly.     

The development of the Jamming Avoidance Response (JAR) in Eigenmannia: An innate behavior indeed

Summary In its Jamming Avoidance Response (JAR), the gymnotiform electric fish Eigenmannia shifts its electric organ discharge (EOD) frequency away from similar interfering frequencies. Continual behavioral measurements were carried out in 164 juvenile fish until a correct JAR emerged. Sixty-four of these fish were raised in complete isolation, the remainder in a community of their siblings. A correct JAR emerged in fish of 1.2–1.6 cm in body length, corresponding to a developmental age of 24–32 days. In 6 of 164 fish, the emergence of a correct JAR followed an interim appearance of an incorrect JAR, which involved frequency shifts in the direction opposite to those of a correct JAR. The fish raised in isolation developed the same forms of behavior and showed the same sequence in their appearance as did socially raised fish. This indicates that the JAR and its developmental schedule are innate. The appearance of an incorrect JAR suggests initial errors or incompleteness in the wiring of central nervous connections. A correct JAR ultimately emerged even if a stimulus regimen was offered that rewarded frequency shifts in the direction opposite to those of a correct JAR. This indicates that the development of the JAR is immune to experimental alterations of sensory experience.Abbreviations Df frequency difference between a jamming stimulus and fish's EOD - ELL electrosensory lateral line lobe - EO electric organ - EOD electric organ discharge - JAR Jamming Avoidance Response - nE nucleus electrosensorius - nE subnucleus of nE, causing drop of EOD frequency - nE subnucleus of nE, causing rise of EOD frequency - Pn pacemaker nucleus - PPn prepacemaker nucleus     

大豆灰斑病抗性遗传的三点测交分析

本实验利用三点测交分析的方法, 对3个组合在人工接种大豆灰斑病菌的条件下的抗性表现进行基因效应分析,各组合均存在加性,组合1存在显性,组合2、3存在上位性。 Abstract:In this paper,Triple Test Cross Design was used in studing the resistance of soybean to 10 physiological race of Cercospora Sojina Haraby inoculation.Results o analysis of gene effects of resistance indicated that additive effect is significant in all the three crosses,dominant effect exsists only in the cross 1 and epistatic effect remains in the cross 2 and cross 3.     

小麦品种联合试验效应及理论依据──Ⅰ.试验的地点环境效应

本文利用小麦品种区域试验材料,研究了联合试验地点对品种适应性鉴定的致变能力以及对试验区域的代表性,讨论了试验的效果．