Pheromones

The effect of sensory input on hormones is essential to any explanation of mammalian behavior, including aspects of physical attraction. The chemical signals we send have direct and developmental effects on hormone levels in other people. Since we don t know either if, or how, visual cues might have direct and developmental effects on hormone levels in other people, the biological basis for the development of visually perceived human physical attraction is currently somewhat questionable. In contrast, the biological basis for the development of physical attraction based on chemical signals is well detailed.

Within laboratory–induced swarms of the marine copepodTemora longicornis, the male exhibits chemically mediated trail–following behaviour, concluding with fluid mechanical provocation of the mate–capture response. The location and structure of the invisible trail were determined by examining the specific behaviour of the female copepods creating the signal, the response of the male to her signal, and the fluid physics of signal persistence. Using the distance of the mate–tracking male from the ageing trail of the female, we estimated that the molecular diffusion coefficient of the putative pheromonal stimulant was 2.7 times–5cm2s–1, or 1000 times slower than the diffusion of momentum. Estimates of signal strength levels, using calculations of diffusive properties of odour trails and attenuation rates of fluid mechanical signals, were compared to the physiological and behavioural threshold detection levels. Males find trails because of strong across–plume chemical gradients; males so...

Honey bees undergo a physiological transition from nursing to foraging approximately 21 days after adult emergence. This transition is delayed by ethyl oleate (EO), a primer pheromone produced by foragers when exposed to ethanol from fermented nectar. We demonstrate here that two secreted α/β-hydrolases (BeeBase ID: GB11403 and GB13365) are responsible for the reversible esterification of ethanol with oleic acid, giving EO. Expression of hydrolase GB11403 was shown to be significantly up-regulated in foragers, relative to nurses. Tissue perfusion experiments with labeled substrates consistently localized the highest level of EO production in the head, whereas insitu imaging revealed expression of relevant EO biosynthetic genes and enzymatic activity along the esophagus, the site of ethanol exposure during nectar intake. Both α/β-hydrolases were expressed in Pichia pastoris, purified and were shown produce EO in vitro. Experiments with live bees fed ethanol demonstrated that EO forme...

 Queenless workers of the Cape honeybee (Apis mellifera capensis) can develop into reproductives termed pseudoqueens. Although they morphologically remain workers they become physiologically queenlike, produce offspring, and secrete mandibular gland pheromones similar to those of true queens. However, after queen loss only very few workers gain pseudoqueen status. A strong intracolonial selection governs which workers start oviposition and which remain sterile. The “queen substance”, 9-keto-2(E)-decenoic acid (9-ODA), the dominant compound of the queen's mandibular gland pheromones, suppresses the secretion of queenlike mandibular gland pheromones in workers. It may act as an important signal in pseudoqueen selection. By analysing the mandibular gland pheromones of workers kept in pairs, we found that A. m. capensis workers compete to produce the strongest queen-like signal.

Menstrual synchrony was examined in three groups of women: 1) mothers and their daughters; 2) women sharing a room in a private residence; and 3) women sharing a room in a dormitory. The intracouple difference in menstrual onset dates was the dependent measure. Mothers and daughters living in the same domicile displayed a significant degree of synchrony. Roommates in private residences were also synchronous, although not significantly more than roommates residing in dormitories.

The human chemosignal, Delta 4,16-androstadien-3-one modulates psychological state without being consciously discernible as an odor. This study demonstrates that Delta 4,16-androstadien-3-one (androstadienone) alters cerebral glucose utilization both in subcortical regions and in areas of the neocortex not exclusively associated with olfaction. These widely distributed changes are consistent with modulation of an integrated neural network for regulation of emotional and attentional states. This is the first study to demonstrate the effects of a sustained chemosignal on brain metabolism and to show that they are similar to those of long acting chemical substances that affect psychological states. Moreover, this provides the first evidence that a human chemosignal has distributed effects on cortical processes and brain metabolism even when it is not detected consciously.

During the 1960s, the California pear industry, on a per acre basis, was among the heaviest users of pesticides. Each season, multiple sprays of up to 14 active ingredients (chlorinated hydrocarbons, organophosphates and carbamates) were typically applied for control of insects and mites. The cost of control escalated while damage from arthropod pests increased owing to greater pest resistance and more pest resurgence. The pear industry suffered classic symptoms of the ‘pesticide treadmill’. By the late 1960s, key pear industry leaders demanded action. Simultaneously, newly emerging concepts of IPM were being developed and funded. With public awareness and environmental activism on the rise in the wake of Rachel Carson's Silent Spring, the stage was set for change. This paper elucidates how pear growers, university researchers and extension agents, environmentalists, government regulators, private consultants, farm chemical suppliers and others contributed to the reduction in insecticide use in California pear orchards. Today, arthropod IPM in pears is characterized as relatively low input, biologically intensive and very successful. For example, in 2008 many pear growers only applied between three and five active ingredients (mainly organically certified) per season for control of arthropods. Copyright © 2009 Society of Chemical Industry

Worldwide, an important aspect of invasive insect pest management is more effective, safer detection and control systems. Phenyl propanoids are attractive to numerous species of Dacinae fruit flies. Methyl eugenol (ME) (4-allyl-1, 2-dimethoxybenzene-carboxylate), cue-lure (C-L) (4-(p-acetoxyphenyl)-2-butanone), and raspberry ketone (RK) (4-(p-hydroxyphenyl)-2-butanone) are powerful male-specific lures. Most evidence suggests a role of ME and C-L/RK in pheromone synthesis and mate attraction. ME and C-L/RK are used in current fruit fly programs for detection, monitoring, and control. During the Hawaii Area-Wide Pest Management Program in the interest of worker safety and convenience, liquid C-L/ME and insecticide (i.e., naled and malathion) mixtures were replaced with solid lures and insecticides. Similarly, Male Annihilation Technique (MAT) with a sprayable Specialized Pheromone and Lure Application Technology (SPLAT), in combination with ME (against Bactrocera dorsalis, oriental fruit fly) or C-L/RK (against B. cucurbitae, melon fly), and the reduced-risk insecticide, spinosad, was developed for area-wide suppression of fruit flies. The nontarget effects of ME and C-L/RK to native invertebrates were examined. Although weak attractiveness was recorded to flower-visiting insects, including bees and syrphid flies, by ME, effects to native Drosophila and other Hawaiian endemics were found to be minimal. These results suggested that the majority of previously published records, including those of endemic Drosophilidae, were actually for attraction to dead flies inside fruit fly traps. Endemic insect attraction was not an issue with C-L/RK, because B. cucurbitae were rarely found in endemic environments.

In the present scenario of Information and Technology, Cloud Computing has become buzzword. Here, dynamically scalable services and distributed virtualized resources are provided over the internet on pay-as-per use basis. Instantaneously, there are huge numbers of users accessing services of cloud and various tasks need to be handled in the cloud computing environment, the high effective task scheduling algorithm is one of the crucial problems that the cloud computing is required to solve. Cloud task scheduling is an NP-hard optimization problem and many different meta-heuristic algorithms have been proposed to solve it. A good task scheduler should adapt its scheduling strategy dynamically according to the changing environment and the types of tasks. Aiming to the model structure of cloud computing, in this article we have introduced modified Ant Colony Optimization algorithm (ACO) to combine with optimized task scheduling algorithm which is dynamic and adapt according to the availability of resources. This paper relates advanced heuristic and combinatorial optimization problem solving technique i.e. Ant Colony Optimization (ACO) which outperforms over other evolutionary algorithm and optimization technique. In proposed algorithm, group of tasks are represented as workflow are scheduled by ants based on heuristic function to the virtual machine. This means all the available tasks are efficiently scheduled to the very best of its optimization. We recompile the cloudsim and simulate the proposed algorithm and results of this algorithm are compared with sequential task scheduling. The experimental results indicates that proposed algorithm has high performance in terms of least execution time that considers heterogeneous resources and elasticity of clouds that can be dynamically acquired on pay-per-use basis. This algorithm is not only beneficial to user and service provider, but also provides better efficiency by applying load-balancing feature i.e. benefit at system level.