Hybrid flies, self control vs willpower & exercise & time of the day | Last Week in Science (14 April 2024)

Flying across boundaries

Mating boundaries exist between species, i.e., an organism of one species does not mate with that of another species. This is true even for closely related species like different species of mosquitoes. In a study conducted at Max Planck Institute for Chemical Ecology, scientists saw the mating boundaries between species dissolving in the presence of commonly occurring air pollutants like ozone.

Ozone when present in high levels can destroy chemicals. The scientists found that ozone destroys pheromones in a type of insect known as fruit fly. Many species including fruit flies rely on chemicals called as pheromones for attracting mates. What will happen if the pheromones are no longer present to guide the flies for choosing their mates?

Scientists studied four different species of fruit fly to understand this destructive effect of ozone. In the presence of high levels of ozone, the female flies got confused and many a times chose the male of another species instead of their own species. This mating produced hybrid offsprings that were sterile i.e. not having the ability to reproduce. Thus, it appears that mating between different species can cause loss of species if the hybrid offsprings cannot reproduce. This breakdown of mating barriers may be one of the ways in which air pollution is causing a loss in the diversity of insects.

References:

Oxidant pollutant ozone removes mating barriers between fly species

Elevated ozone disrupts mating boundaries in drosophilid flies

Exercise and the time of the day

Have you wondered what time of the day is best to exercise? While we may not know if it applies to all but a recent study conducted at University of Sydney has provided an answer for people with obesity.

Physical activity stretches or chunks of more than three minutes that makes one breathless reduce the risk of developing heart disease and type 2 diabetes. The kind of vigorous activity that makes one breathless increases one's oxygen demand and so increases the heart rate to supply more blood and oxygen to the muscles that are being exercised. In stretches of strenuous exercise that last less than 3 minutes, the muscles can work even without oxygen and has been found to be less beneficial.

Researchers recorded physical activity that included more than 3 minutes of strenuous activity in 30,000 individuals using wearable devices - like the one that is used to count steps. Their goal was to understand what time of the day - morning, afternoon, or evening is most beneficial for exercising in people with obesity. These 30,000 individuals were tracked for 8 years to record the development of cardiovascular disease, diabetes, or death. The researchers found that physical activity done during late afternoon or evening time is most effective in reducing the risk of heart disease and type 2 diabetes. The researchers did not include the total time of strenuous exercise which they suggest to be studied in future.

References: 
Does the time of day you move your body make a difference to your health?
Timing of Moderate to Vigorous Physical Activity, Mortality, Cardiovascular Disease, and Microvascular Disease in Adults With Obesity

Self-control vs willpower

Although self-control and willpower are used interchangeably but lately the difference between the two has been recognized. Willpower can be thought of as an internal force to exercise self-control that can also be achieved via external strategies of incentives, restrictions, and punishments. Despite the effectiveness of such strategies, there seems to be a reluctance in using external strategies for self control to achieve one's goals.

To understand this reluctance, researchers designed multiple tests which were taken by 2800 participants in the United States. In one of the tests, participants were given 0.5$ and asked to loan it to a hypothetical second player. The amount would get tripled when received by the second player to 1.5$ and the second player would have the option to either keep it to themselves or split the half 0.75$ with the first player. More than 69% of the participants passed the money to the second player who exercised his willpower to achieve his goal instead of using an external strategy like a blocking app to not get distracted.

The scientists behind the study suggest that the use of incentives may be seen as an individual's admission of past failures to achieve something through self-control, which is perceived as a moral failure, thereby diminishing their integrity. Thus, despite the effectiveness and acceptance of external strategies and incentives in achieving goals or breaking habits, individuals who use them are perceived as less trustworthy. 

One of the interesting findings of the study was that the participants' trust did not depend on the usage of an external method but rather on the choice that a hypothetical individual made to use it. The study also revealed that individuals are more likely to use incentives when they know others won't find out. 

References: 

People who use willpower alone to achieve goals, resist temptation, deemed more trustworthy

Going Beyond the “Self” in Self-Control: Interpersonal Consequences of Commitment Strategies

Editing and suggestions by Ashish Gourav