Mate-guarding males are a convenient temporal sun shield as a parasol for ovipositing females. Illustration credit: Koutaro Ould Maeno. Credit: Ecology (2024). DOI: 10.1002/ecy.4416
A team of entomologists at Center National de Lutte Antiacridienne’s Mauritanian National Desert Locust Center has found that male locusts will mount a female when she is laying eggs during the heat of day.
In their study, published in the journal Ecology, the group conducted field expeditions and carried out experiments to test for heat protection from male locusts.
Prior research and anecdotal evidence have found that locust swarms can decimate large swaths of croplands in short order and that they reproduce quickly. Some research has also suggested that while females generally lay their eggs in the evening, when it is cooler outside, some have been observed doing so during the hot daylight hours.
The researchers wondered how the females could achieve such a feat, and to find out, they made several trips around the Sahara during times when locusts were swarming. They observed that the males were mounting the females as if to mate while she was laying eggs, but only during the daytime. Similar behavior had been seen in male locusts at night, where the behavior was found to keep other males from interfering with females’ egg laying.
To make sure it was not a random event, the researchers searched out pairs during times when the desert floor reached up to 48°C—under such conditions, they found that approximately 90% of the females were being mounted by males. They also noted that pairs moved in tandem as the sun moved across the sky, staying parallel to its rays. Using thermal cameras showed that the bodies of the females were cooler than those few females not being mounted.
The researchers also conducted a simple experiment: They glued dead locusts to sticks and tied them to the ground—some in pairs, some alone. In recording the body temperature of the dead locusts, they found that their bodies served as a shield against the sun’s heat—those underneath were cooler.
The research team suggests their findings could lead to new pesticide strategies to combat locust infestations, preventing loss of crops.
More information:
Koutaro Ould Maeno et al, Mate‐guarding male desert locusts act as parasol for ovipositing females in an extremely hot desert environment, Ecology (2024). DOI: 10.1002/ecy.4416
Citation:
Male locusts serve as parasols for females during egg laying in the hot sun (2024, October 8)
retrieved 8 October 2024
from https://phys.org/news/2024-10-male-locusts-parasols-females-egg.html
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Gender rating gap across platforms. Credit: Nature Human Behaviour (2024). DOI: 10.1038/s41562-024-02003-6
A new study led by Dr. Andreas Bayerl from Erasmus School of Economics, Dr. Yaniv Dover from The Hebrew University, and Prof. Hila Riemer and Prof. Danny Shapira from the Ben-Gurion University of the Negev has identified a significant and consistent gender rating gap in online reviews, revealing that women’s average ratings are higher than men’s across major platforms such as Amazon, Google, IMDb, TripAdvisor, and Yelp.
Relying on the analysis of more than 1.2 billion actual online reviews, supplemented by two controlled lab experiments, this research suggests that gender differences in the willingness to share negative feedback drive this gap.
The findings reveal that, although women and men generally have similar attitudes about products or experiences, women are more hesitant to express negative opinions in online public forums. This reluctance may stem from societal expectations that place greater emphasis on communal and empathetic behavior in women, leading them to avoid backlash or negative evaluations.
The researchers stated “Our findings point to a broader societal issue. Women are less likely to express dissatisfaction in online reviews, not because they are more satisfied, but because they are more concerned about potential social consequences when expressing dissatisfaction.”
Key findings from the study include:
Women’s average ratings are higher than men’s by approximately 0.1 stars on a 5-point scale. Such a gap is important and impactful for online reviews, especially since small differences in online review scores lead to meaningful changes in ranking, which have significant economic implications.
Lab experiments found that when dissatisfied, women are less likely than men to post a review, while satisfied women and men submit reviews at similar rates.
The gender rating gap holds across many contexts, platforms, and geographies, suggesting it is a pervasive issue in online review culture.
The researchers also discuss potential solutions to reduce the bias in online review ratings and call for further research on the topic. Suggestions include encouraging platforms to create more inclusive spaces where women feel comfortable sharing their honest opinions and also considering the option of anonymous reviews.
The researchers note, however, that anonymity can sometimes lead to more toxic environments, so platform managers must balance transparency with inclusiveness.
These findings have significant implications for consumers, businesses, online platforms, and society at large. Given online reviews‘ critical role in influencing purchasing decisions, the gender rating gap may distort perceptions of products and services. Small rating differences can lead to large shifts in rankings, potentially disadvantaging businesses or creating misinformed consumer choices.
“This research is a call to action for platforms, businesses, and society as a whole,” the researchers emphasize. “To ensure fair representation of opinions, we need to address the factors that prevent individuals, particularly women, from sharing their true experiences, especially when they are dissatisfied.”
More information:
Andreas Bayerl et al, Gender rating gap in online reviews, Nature Human Behaviour (2024). DOI: 10.1038/s41562-024-02003-6
Citation:
Gender rating gap in online reviews study reveals women are less likely to share negative experiences (2024, October 8)
retrieved 8 October 2024
from https://phys.org/news/2024-10-gender-gap-online-reveals-women.html
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Gabriel Meyer inserts the rock sample into the press core, which can reach temperatures of 100°C. Credit: EPFL/A.Herzog – CC-BY-SA 4.0
A team of EPFL scientists has provided insight into the mechanisms at work in geothermal reservoirs located deep underground, known as supercritical reservoirs. Through a combination of computer simulations and lab experiments, they showed that rocks located between 5 and 8 kilometers deep in the Earth’s crust are also permeable to fluids.
Geology is a field with many unanswered questions. And the deeper you dig into the Earth’s crust, the further you venture into unknown territory, as the rock becomes increasingly hidden and hard to reach. The deepest hole in the world is on the Kola Peninsula in Russia, and extends 12 kilometers—yet that’s less than 25% of the average depth of the continental crust.
And even though geologists have been able to dig that far, it’s nearly impossible to take measurements at such depths. That’s why many scientists are working to replicate the conditions inside their research labs.
This is the method that Gabriel Meyer, a postdoc at EPFL’s Laboratory of Experimental Rock Mechanics (LEMR), chose to use for his research. He’s looking specifically at the changes that take place in rocks under supercritical conditions.
“Scientists have observed a transition in the mechanical behavior of rocks at extreme depths,” he says. “I wanted to be able to understand what’s going on, since we can’t actually watch the process out in the field.”
His task has now become easier thanks to a new instrument developed at LEMR that can replicate the pressure and temperature conditions at such depths. It took Prof. Marie Violay, the head of LEMR, and her research group nearly six years to create this piece of equipment. The first discoveries enabled by the instrument have just been published in Nature Communications.
Credit: Ecole Polytechnique Federale de Lausanne
Water at more than 400°C
Geothermal reservoirs with supercritical water—or water at temperatures above 400°C—are the next frontier of geothermal energy. Engineers have been exploring the potential of this natural resource in different parts of the world for the past 15 years or so, since it could boost energy production by a factor of 10 relative to conventional geothermal plants (which source heat closer to the surface).
Supercritical reservoirs are located approximately 10 kilometers underground, and the trick is to reach them. The first conclusive tests of supercritical geothermal technology were carried out entirely in volcanic regions, where supercritical temperatures can be found at depths of 5 kilometers.
“When you get near the 10-kilometer mark, the rock no longer fractures but instead deforms uniformly, like soft caramel, and its behavior becomes complex. Deformation occurs at the level of the crystalline structures in the grain. I wanted to find out whether water could circulate within rock that has transitioned into this unusual ductile form,” says Gabriel Meyer, postdoc at EPFL’s Laboratory of Experimental Rock Mechanics.
Supercritical water is neither a gas nor a liquid, but is in a state that allows large amounts of energy to be extracted. The mechanical properties of rock also change under such conditions. Whereas rock close to the surface can be brittle and contain a number of microfractures, it becomes ductile at high depths.
“When you get near the 10-kilometer mark, the rock no longer fractures but instead deforms uniformly, like soft caramel, and its behavior becomes complex,” says Meyer. “Deformation occurs at the level of the crystalline structures in the grain. I wanted to find out whether water could circulate within rock that has transitioned into this unusual ductile form.”
Picture of an intact specimen of Lanhélin granite. Credit: Nature Communications (2024). DOI: 10.1038/s41467-024-52092-0
3D imagery
To measure rock permeability, Meyer and his colleagues transformed granite samples from brittle to ductile by exposing them to the same temperature and pressure conditions that are found deep inside the Earth’s crust. The LEMR instrument works by exerting pressure on a rock sample and deforming it with a piston.
Both the temperature and pressure gradually increase, simulating the conditions between a few hundred meters and several kilometers underground. Then, the research team used a synchrotron to produce 3D scans of the deformed samples, enabling them to view the permeability.
“Geologists long thought that the brittle-to-ductile transition point was the lower bound for water circulation in the Earth’s crust,” says Meyer. “But we showed that water can also circulate in ductile rock. This is a highly promising discovery that opens up further avenues of research in our field.”
More information:
Gabriel G. Meyer et al, Permeability partitioning through the brittle-to-ductile transition and its implications for supercritical geothermal reservoirs, Nature Communications (2024). DOI: 10.1038/s41467-024-52092-0
Citation:
Scientists explore geothermal energy potential in supercritical reservoirs (2024, October 8)
retrieved 8 October 2024
from https://phys.org/news/2024-10-scientists-explore-geothermal-energy-potential.html
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Until now, it was considered certain that people are more likely to cooperate if the benefits from cooperation are higher. A recently published, large-scale study involving researchers from Innsbruck has now called this finding into question: in over 2,000 study participants, the researchers found no relationship between benefits from cooperation and willingness to cooperate.
A study published in the Proceedings of the National Academy of Sciences challenges long-held assumptions about human cooperation. Traditionally, behavioral scientists and economists have primarily studied cooperation in public good contexts through repeated interactions, where individuals can build trust and reciprocal relationships, adjusting their behavior based on the actions of others.
However, many real-world, naturally occurring situations, such as volunteering or donating to crisis relief efforts, are one-time decisions with no obvious future interactions or relationships to consider.
This new study, co-authored by Dr. Natalie Struwe and Prof. Esther Blanco from the University of Innsbruck with Prof. James Walker from Indiana University, explored how individuals cooperate when they only have one opportunity to cooperate in a social group, not knowing the identity of other group members.
Two large-scale experiments
Across two experiments involving over 2,000 participants, the researchers varied the potential benefits from cooperation in public good provision. Despite the increased benefits for cooperating, the study found no significant change in how much individuals were willing to cooperate.
The mechanism behind this behavior seems to lie in individuals’ expectations of others’ willingness to cooperate, which were also not found to vary with the benefits of cooperating. As participants did not expect others to cooperate more when benefits increased, they were unlikely to increase their own cooperation efforts—even when the benefits of cooperation doubled.
“Our findings highlight a critical gap in our understanding of cooperative behavior in single-encounter settings,” said Dr. Natalie Struwe of the Department of Public Finance at the University of Innsbruck.
“The decision to cooperate is characterized by what we call a social dilemma. These are situations where self-interest is in conflict with social interests. With higher benefits from cooperation, however, this conflict is much lower and we would expect to see much higher cooperation rates.
“But, we were surprised to see that even when we dramatically increased the benefits from cooperation, people’s cooperation efforts did not rise accordingly. This suggests that real-world cooperation—such as donating to immediate disaster relief—may not always be driven by an assessment of increased benefits.”
Consistent results across data collections
“We couldn’t believe the results ourselves at first, double-checked the data several times, and repeated the study with several populations,” said Professor Esther Blanco of the Department of Public Finance at the University of Innsbruck.
“In the end, we gathered nearly 2,000 data points, conducting experiments online with the general population from the UK, as well as with our students—both online and in our laboratory.
“No matter what we did, the results remained consistent: cooperation levels were remarkably stable. The general public was no more or less cooperative than our students. On average, participants were willing to invest around 40% of their available money to boost their group’s earnings, regardless of the specific setting.”
“Spontaneous cooperation in one-time situations is more common than we might think,” Professor James Walker, another of the co-authors, at the Department of Economics of Indiana University, explained.
“For example, people coming together to provide immediate disaster relief is a case of one-time cooperation, where individuals decide to act and help without knowing whether they will interact with the same people again.”
The study’s results have important implications for how we think about encouraging cooperation in public good provision, especially in urgent, one-time scenarios like disaster relief or emergency volunteering. It also points to the need to better understand the fundamentals of cooperative behavior, one of the most defining characteristics of humankind.
Key findings
Individuals do not significantly change their contributions to public goods when the benefits from cooperation increase, in contrast to previous research in repeated interactions.
Expectations about others’ contributions strongly influence individual behavior in one-time settings and do not vary significantly with changes in benefits from cooperation.
Average cooperation levels remained consistently around 40% across different participant groups and experimental settings, including both the general public and university students.
The study underscores the need for further research into cooperation in one-time decision settings, in particular how individuals interpret the benefits and respond in such settings, as well as how they expect others to respond.
This research opens new avenues for exploring how to effectively foster cooperation in critical single encounter situations and calls for a deeper understanding of the psychological and social factors at play.
More information:
Natalie Struwe et al, Increasing benefits in one-time public goods does not promote cooperation, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2410326121
Citation:
Study questions link between cooperation and societal benefits (2024, October 8)
retrieved 8 October 2024
from https://phys.org/news/2024-10-link-cooperation-societal-benefits.html
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Managed honey bees. Credit: Bianca Ackermann, public domain
There are nearly 4,000 native bee species in the United States, contributing to pollination in agricultural, urban and natural landscapes. Honey bees, however, are not native to the U.S., which has led to concerns that managed honey bee populations might negatively impact wild bees via competition for resources and sharing of pathogens, according to researchers at Penn State.
However, the team recently found that of the 33 genera of native bees studied, only a small number seemed to be negatively affected by the presence of honey bees.
The findings will help identify the groups of bees that may be most at-risk and aid in creating conservation strategies, according to Gabriela Quinlan, lead author on the study and a U.S. National Science Foundation (NSF) postdoctoral research fellow in Penn State’s Center for Pollinator Research and the College of Agricultural Sciences.
The researchers found that the presence of managed honey bee apiaries and/or urban land correlated with reduced numbers of bees from six of 33 wild bee genera, suggesting that one of these factors negatively impacts these bees’ ability to maintain their populations. Since the honey bee apiaries in the study were located in greater densities in urban areas, the researchers sought to disentangle the relative role of apiary density versus developed land.
The six bee genera showed different responses to these two factors, with apiary density having the greatest negative impact on the long-horned bees in the genus Svastra, while the abundance of Florilegus, which is also a long-horned bee, was associated most negatively with urbanization. The others include green bees in the genera Agapostemon and Augochlora, sweat bees in the genus Lasioglossum and long-horned bees in the genus Melissodes.
After analyzing the data, the researchers found the genera most affected by apiaries and land development tend to nest in the ground, forage later in the season and, in some cases, specialize on specific types of seasonal flowering plants.
“Urban environments can be especially challenging for ground-nesting bees because the hardscaping—asphalt and concrete—can make it difficult to find bare ground for nesting,” Quinlan said. “Small bees can’t fly very far, so they may have trouble finding nesting and flowering resources within their flight range. Moreover, specialist bees require very specific flowers, which may be difficult to find in urban settings.”
Quinlan explained that some wild bees also forage later in the season, which happens to be when honey bee colonies are at their peak size and competing for limited floral resources.
“Planting late-season forage and leaving bare ground as nesting resources in urban gardens could help alleviate some of the stressors that developed land and urban beekeeping can put on these bee groups,” Quinlan said.
For their study, the researchers obtained the locations of nearly 4,000 registered apiaries across the state of Maryland and used this information to build a state map of apiary density. They then compared this with data on wild bee populations from within the state’s boundaries collected by the U.S. Geological Survey’s Bee Monitoring and Identification Lab.
In recent decades, the researchers said, there has been wide recognition that pollinators are experiencing declines associated with pesticides, pathogens, poor nutrition and climate change. There also has been increased attention paid to how honey bees may affect wild, native bees by transmitting pathogens and exacerbating competition for resources.
But despite these strong concerns, evidence of the effects honey bees have on wild bee abundance was lacking in the literature.
“There is very little data on population sizes of most wild bee species across the U.S., so we did not have a good understanding of the factors that influence the abundance of different wild bee species,” said Christina Grozinger, Publius Vergilius Maro Professor of Entomology, director of the Center for Pollinator Research and co-author on the study.
“Here, we explicitly tested the question of whether the presence of managed honey bee populations was linked with reductions in wild bee abundance.”
The study provided additional insights into how different bee genera, with different natural histories, are influenced by environmental factors, Quinlan noted.
For example, they also found that apiary density negatively affected the abundance of Triepeolus—a cuckoo bee—which parasitizes the nests of long-horned bees like Svastra. In this case, it may be the negative impact of apiary density on Svastra abundance that causes a negative effect on Triepeolus abundance.
Grozinger noted that this highlights the interconnectedness of these different species, and the importance of thinking about bees as communities, not as individual species.
The researchers said that in the future, additional studies could be done in other areas of the U.S. to further tease out genera- and species-specific wild bee responses to honey bees. The new INSECT NET graduate training program at Penn State is aiming to develop nonlethal, automated monitoring systems for bees and other insects that will help with these studies.
In the meantime, Grozinger said one of the best ways people can help both wild and managed bees is to add more flowering plants to the landscape, including city streets and backyards.
“Native flowering trees and shrubs in particular provide a bonanza of resources for bees,” she said. “Beekeepers can help their bees become more resilient to climate variation by managing pests and diseases within their colonies, and this can also reduce the potential for honey bees to spread diseases to wild bees.”
More information:
Gabriela M. Quinlan et al, Estimating genus-specific effects of non-native honey bees and urbanization on wild bee communities: A case study in Maryland, United States, Science of The Total Environment (2024). DOI: 10.1016/j.scitotenv.2024.175783
People can learn more about the resources available to bees in their area, and the risks posed by pesticide use and weather conditions, by using Penn State’s Beescape decision-support tool.
Citation:
Adding fall blooming plants may help both managed and wild bees in cities (2024, October 8)
retrieved 8 October 2024
from https://phys.org/news/2024-10-adding-fall-blooming-wild-bees.html
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