The olfactory gating of visual preferences to human skin and colors in mosquitoes

Mosquitoes track odors, locate hosts, and find mates visually. The color of a food resource, such as a flower or warm-blooded host, can be dominated by long wavelengths of the visible light spectrum (green to red for humans) and is likely important for object recognition and localization. However, little is known about the hues that attract mosquitoes or how odor affects mosquito visual search behaviors. We used a real-time 3D tracking system and wind tunnel that allowed careful control of the olfactory and visual environment to quantify the behavior of more than 1.3 million mosquito trajectories. We found that CO2 induces a strong attraction to specific hues, including those that humans perceive as cyan, orange, and red. Sensitivity to orange and red correlates with mosquitoes' strong attraction to the color spectrum of human skin, which is dominated by these wavelengths. Attraction was eliminated by filtering the orange and red bands from the skin color spectrum and by introducing mutations targeting specific long-wavelength opsins or CO2 detection. Collectively, our results show that odor is critical for mosquitoes' wavelength preferences and that the mosquito visual system is a promising target for inhibiting their attraction to human hosts.

Strong attraction of male mosquitoes (Aedes aegypti) to humans

Female Aedes aegypti mosquitoes integrate multiple sensory cues to locate human hosts for blood meals. While male mosquitoes do not blood feed, male Ae. aegypti swarm around and land on humans in nature. Basrur et al. (2020) generated male Aedes aegypti lacking the fruitless gene and discovered that they gained strong attraction to humans, similar to female mosquitoes. The authors assume that host-seeking is a female-specific trait, which they confirmed through experiments. However, all experiments were performed under confined laboratory conditions which appear to inhibit swarming behavior. We used semi-field experiments to demonstrate robust attraction of male Ae. aegypti to humans. Human-baited traps captured up to 25% of released males within 15 min, whereas control traps without humans as bait failed to capture males. Rapid attraction to humans was further demonstrated through videography. Males swarmed around and landed on human subjects, with no activity recorded in paired unbaited controls. The absence of female Ae. aegypti in these experiments rules out a hypothesis by Basrur et al. (2020) that males are attracted not to the human, but to host-seeking females near humans. Finally, we confirm the lack of male attraction to humans in small laboratory cages, even when using recently field-collected males. Our direct observations of male mosquito attraction to humans refute a key assumption of Basrur et al. (2020) and raise questions around conditions under which fruitless prevents male host-seeking. Male mosquito attraction to humans is likely to be important for mating success in wild populations and its basis should be further explored.

On the strong attraction of functions on dependent variables to the normal law

For symmetric functions on random variables from stationary sequences satisfying the uniformly strong mixing condition, the general conditions of attraction to the normal law in terms of distributions of individual items are obtained. The main result of the paper generalizes all known to present results of this type.

How to form a wormhole

We provide a simple but very useful description of the process of wormhole formation. We place two massive objects in two parallel universes (modeled by two branes). Gravitational attraction between the objects competes with the resistance coming from the brane tension. For sufficiently strong attraction, the branes are deformed, objects touch and a wormhole is formed. Our calculations show that more massive and compact objects are more likely to fulfill the conditions for wormhole formation. This implies that we should be looking for wormholes either in the background of black holes and compact stars, or massive microscopic relics. Our formation mechanism applies equally well for a wormhole connecting two objects in the same universe.

fruitless mutant male mosquitoes gain attraction to human odor

SUMMARYWhile sexual dimorphism in courtship and copulation behavior is common in the animal kingdom, sexual dimorphism in feeding behavior is rare. The Aedes aegypti mosquito provides an example of extreme sexual dimorphism in feeding, because only the females show strong attraction to humans, and bite them to obtain a blood-meal necessary to stimulate egg production1-8. The genetic basis of this complex, modular, and sexually dimorphic feeding behavior is unknown. The fruitless gene is sex-specifically spliced in the brain of multiple insect species including mosquitoes9-11 and encodes a BTB zinc-finger transcription factor that has been proposed to be a master regulator of male courtship and mating behavior across insects12-17. Here we use CRISPR-Cas9 to mutate the fruitless gene in male mosquitoes. fruitless mutant males fail to mate, confirming the ancestral function of this gene in male sexual behavior. Remarkably, fruitless mutant males also gain strong attraction to a live human host, a behavior that wild-type males never display. Humans produce multiple sensory cues that attract mosquitoes and we show that fruitless specifically controls hostseeking in response to human odor. These results suggest that male mosquitoes possess the neural circuits required to host-seek and that removing fruitless reveals this latent behavior in males. Our results highlight an unexpected repurposing of a master regulator of male-specific sexual behavior to control one module of female-specific blood-feeding behavior in a deadly vector of infectious diseases.

Quality versus quantity: An assessment of the impact of Michelin-starred restaurants on tourism in Spain

The number of internationally recognized Michelin-starred restaurants in a place is a new trend used to measure a tourist destination’s culinary standard. The purpose of this study is to close the gap created by the lack of econometric studies on the tourist attraction of Michelin-starred restaurants, especially in Spain. Panel data methodology is applied to 50 Spanish NUTS-3 regions over a broad time period (2000–2016) to assess the impact of Michelin-starred restaurants on tourism demand from both domestic and foreign tourists. The findings show that restaurant quality is more important than quantity in the gastronomy–tourism relationship and that Michelin-starred restaurants are a strong attraction for foreign tourists. Some policies are suggested, such as the development of Culinary Schools and marketing campaigns to promote haute cuisine tourism.

In Search of the Secrets of the Levant: Observations on Egyptian Mummies in the Accounts of 17th Century European Travellers (1601-1679)

Considered to be a medicine with extraordinary virtues, Egyptian mummies supplied a flourishing market in the 17th century. At this time, when thanatopraxy was still little known in Europe, mummies also catalyzed the attention of « esprits curieux », to whom they represented one of the must-have item for their collections. Surrounded by this aura of magic and curiosity, they also exerted a strong attraction on travellers exploring or passing through Egypt. The article questions the accounts (published between 1601 and 1679) of some of these travellers, which helped to accumulate empirical knowledge about mummies and contributed to clarifying and demystifying their image, although they were unable to fully unveil their mystery.

Characteristics of Foreign Direct Investment into Agriculture in Ghana

The paper investigated the characteristics of foreign direct investment( FDI) to Ghana's agriculture by examining the flow of funds, projects, employment and possible pre-independence legacies in FDI inflows from Ghana's former partners in colonial relationships and the slave trade. Using moving averages, percentages, cross tabulations and chi-squares tests, to data from 1994-2010, the following conclusions were drawn; a) FDI flows, measured by estimated cost of projects remained stable and low for most part of 1994-2010. However, huge jumps were witnessed after 2008, coinciding with Ghana's second time of successful and peaceful transfer of political power to another government; b) Clustering of agricultural projects in Greater Accra Region, c) a strong attraction of large FDI firms for the crops subsector; d) 75% of the FDI projects are SMEs; e) Among European countries, Ghana's former slave and colonial masters, Britain, Netherlands and Denmark contribute most FDI projects to Ghana's agriculture. Volta Region has strong attraction for projects from Germany. Strategies need to be designed to attract projects beyond Greater Accra, where poverty reduction may be better felt. Keywords: FDI;Agriculture;Employment;Distribution;Projects.