Hexbyte Glen Cove Want to reduce cockroach sex? Block an enzyme thumbnail

Hexbyte Glen Cove Want to reduce cockroach sex? Block an enzyme

Hexbyte Glen Cove

Credit: Unsplash/CC0 Public Domain

It’s not the look in her compound eyes or the shape of her carapace that really attracts the male cockroach to his mate. Instead, it’s all those 29-carbon hydrocarbons in her cuticle that drive him wild. How the female cockroach regulates production of these contact sex pheromones, and what happens when she produces too few, is the subject of a new study publishing on July 27th in the open-access journal PLOS Biology by Tong-Xian Liu of Northwest A&F University in Yangling, China, and colleagues.

The German , Blatella germanica, is the most common, and most despised, cockroach around the world. Like other insects, its exoskeleton is impregnated with a rich mix of molecules, including oily hydrocarbons that help keep the cockroach from drying out. A key feature that distinguishes male from female cockroaches is the abundance of one such , called 3,11-DimethylC29, which is chemically converted into a female sex pheromone. When the male senses the pheromone with his antennae, he raises his wings to expose a nutrient-containing gland. While the female feasts on its contents, the male copulates with her.

Like other long-chain fatty molecules, the pheromone precursor is synthesized in part by elongating a shorter hydrocarbon chain, through the action of a type of enzyme called an elongase. To better understand how that synthesis is regulated, the authors blocked the set of cockroach elongases using RNA interference. When one elongase, BgElo12, was knocked down, they found that the level of the pheromone was reduced and males were less attracted to the affected females.

Using RNAi knockdown, they showed that BgElo12 production was regulated by two insect sex differentiation studied previously in fruit flies. In male cockroaches, a gene called Doublesex repressed the production of the elongase, limiting the amount of pheromone produced. In females, however, another gene, called Transformer, blocked the effect of Doublesex, turning on the elongase gene. The authors showed that knocking down Transformer in females led again to limited production and to reduced sexual attractiveness.

“The identification of this pathway regulating female contact pheromones is valuable,” Liu said, “as it enriches our general understanding of the regulation of insect sexual behavior. Further, the elucidation of this key pathway in the cockroach in particular may well lead to better ways to control reproduction of this globally significant pest.”

More information:
Xiao-Jin Pei et al, Modulation of fatty acid elongation in cockroaches sustains sexually dimorphic hydrocarbons and female attractiveness, PLOS Biology (2021). DOI: 10.1371/journal.pbio.3001330

Want to reduce cockroach sex? Block an enzyme (2021, July 27)
retrieved 28 July 2021
from https://phys.org/news/2021-07-cockroach-sex-block-enzyme.html

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Hexbyte Glen Cove An easy way to reduce socioeconomic disparities thumbnail

Hexbyte Glen Cove An easy way to reduce socioeconomic disparities

Hexbyte Glen Cove

Researchers from Columbia University and Temple University published a new paper in the Journal of Marketing that examines how choice architecture can reduce socioeconomic disparities.

The study, forthcoming in the Journal of Marketing, is titled “Do Nudges Reduce Disparities? Choice Architecture Compensates for Low Consumer Knowledge” and is authored by Kellen Mrkva, Nathaniel Posner, Crystal Reeck, and Eric Johnson.

As Mrkva explains, “Our research demonstrates that people with (SES), low numerical ability, and low knowledge are most impacted by nudges. As a result, ‘good nudges,’ designed to encourage selection of options that are in people’s best interests, reduce SES disparities, helping low-SES people more than high-SES people.” On the other hand, nudges that encourage selection of inferior options exacerbate disparities relative to “good nudges” because low-SES consumers are more likely to retain inferior default options. In other words, nudges are a double-edged sword that can either reduce disparities or make matters worse because they impact low-SES people most. The research team generalized its findings across three different types of nudges, several different consumer contexts, and real retirement decisions.

This research has major implications, including for the COVID vaccination process. Across the country, millions of people are now eligible to get a COVID vaccine. However, the signup process is often unnecessarily complex. New York’s nycHealthy sign-up portal, for example, includes as many as 51 questions and requests that you upload your insurance card. As a result, many people, especially the elderly, poor, and less digitally literate, have struggled or failed to make an appointment. As Johnson explains, “Our research suggests that making beneficial behaviors like vaccination simpler has a crucial and underappreciated advantage—it reduces socioeconomic disparities. On the other hand, when these behaviors are unnecessarily complex, it is typically low-SES consumers who are harmed the most.”

In five experiments as well as data from real retirement decisions, the researchers show that people who are lower in SES, domain knowledge, and numeracy are impacted more by a variety of nudges. As a result, “good nudges” that facilitate selection of welfare-enhancing options reduce disparities by helping low-SES, low-knowledge, and low-numeracy consumers most.

In Study 1, participants made five consumer financial decisions. For each decision, they were randomly assigned to a “no default,” “good default,” or “bad default” condition (the latter two pre-selected correct or incorrect options, respectively). After they made these five decisions, participants completed common measures of the three hypothesized moderators—financial literacy, numeracy, and socioeconomic status. As predicted, there was a large default effect. There were also interactions between the default condition and the three moderators; participants lower in these moderators were more impacted by defaults. These effects remained significant when adding survey engagement, comprehension, need for cognition, agreeableness, decision time, and their interactions with condition to the model as covariates.

Study 2 examines whether these effects generalized across three different types of nudges and three decision contexts. It replicated the SES and financial literacy effects of Study 1 across all nudges and contexts. Unlike Study 1 and all subsequent studies, the x numeracy interaction was not significant. The key effects remained significant when controlling for a measure of fluid intelligence.

Study 3 uses syndicated data from stratified random samples of American households about their retirement investment decisions to examine a sample of people who work for companies that use defaults to automatically enroll employees into retirement contributions. Respondents reported whether they retained or opted out of the default contribution amount and default investment allocation. Evidence supports that lower-SES and less financially literate people are more impacted by nudges and thus less likely to opt out of these retirement defaults: Lower-SES participants were less likely to opt out as were participants with lower financial literacy.

Study 4 replicated these effects in the context of COVID-19 health decisions (e.g., deciding whether to wear a mask). Additionally, domain-specific health knowledge moderated default effects whereas other-domain knowledge did not. Studies 5-6 replicated the predicted moderators from Study 1 with incentives. Mediation models suggest that people with lower SES, domain knowledge, and numeracy were more impacted by nudges partly because they experience higher uncertainty and decision anxiety when making decisions.

Across the six studies, nudges influenced choice disparities across people. Posner summarizes the study by saying “Our results suggest that nudges that make behaviors such as retail purchases, vaccine sign-up, and retirement contributions more automatic can reduce socioeconomic inequities.”

More information:

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