Biology subjects

Ma, I.

Publications and source records attributed to Ma, I..

3 recordsLinked to original sources

bioRxiv2026

Protozoan predation selects for key symbiotic traits in an environmentally transmitted beneficial symbiosis

AbstractBeneficial associations between bobtail squids (Cephalopoda: Sepiolidae) and Vibrio bacteria encompass a unique association where symbionts are obtained environmentally from the surrounding environment. Vibrio symbionts are susceptible to a number of ecological pressures such as protozoan grazing whilst in their free-living state. Impacts of grazing have several consequences for symbiosis characteristics such as biofilm formation, a trait crucial for survival both in and outside the squid. Therefore, in order to ascertain how biotic factors such as grazing in the environment effect symbiotic success, two V. fischeri strains, ES114 and ETBB1-C were experimentally evolved in separate biofilm grazing experiments with the amoeba, Acanthamoeba castellanii and ciliate Tetrahymena pyriformis. Both ES114 and ETBB1-C biofilms were evolved up to 50 generations through serial passaging. At 50 generations, ES114 biofilms displayed variability in response to predation by both predators, whereas ETBB1-C biofilms were more stable across generations of grazing. A. castellanii decreased in population numbers when co-inoculated with ETBB1-C, whereas T. pyriformis increased in numbers with biofilm growth. Growth of V. fischeri biofilms in the presence of grazers such as T. pyriformis has an important role in inducing biofilm growth by acting as a chaperone for recycling nutrients back into the environment. Additionally, V. fischeri colonization fitness in the host was dependent on which grazer was used to evolve the biofilms. Such variation in response by V. fischeri to different types of predation demonstrates the versatility of this symbiont in its free living state and has subsequent impacts on the eventual association with squids. ImportanceThis manuscript demonstrates the importance of biotic factors (such as protozoan grazing) in the environment that effect host colonization in a beneficial symbiosis. Using an experimental evolution approach, this work demonstrates how symbiotic biofilms can adapt to pressures such as grazing that subsequently influences the ability to colonize its invertebrate host.

microbiology↗

bioRxiv2020

The Cognitive Mechanisms That Drive Social Belief Updates During Adolescence

Adolescence is a key life phase for developing well-adjusted social behaviour. Belief updates about the trustworthiness of peers are essential during adolescence as social reorientation emerges and peer relationships intensify. This study maps the age-related changes of those belief updates during adolescence (n = 157, 10-24 years). We used computational modelling and an information sampling paradigm to reveal that three cognitive mechanisms contribute to age-related changes in those belief updates: prior beliefs, prior uncertainty, and uncertainty tolerance. The age-related changes in these three cognitive mechanisms result in increasingly adaptive belief updates from early to mid-adolescence when it comes to beliefs about trustworthiness. Our findings shed light on age-related changes in adaptive learning about others during adolescence.

neuroscience↗

bioRxiv2018

The Cost of Appearing Suspicious? Information Gathering Costs in Trust Decisions

Trust decisions are inherently uncertain, as people have incomplete information about the trustworthiness of the other prior to their decision. Therefore, it is beneficial to gather information about a trustees past behaviour before deciding whether or not to trust them. However, elaborate inquiries about a trustees behavior may change the trustees willingness to reciprocate, causing either a decrease due to the investor appearing suspicious, or an increase because the investor appears to be highly betrayal-averse. Such a change could cause the investor to gather less or more information, respectively. We examine how information acquisition is modulated by social context, monetary cost, and the trustees trustworthiness. Participants had the opportunity to sequentially sample information about a trustees reciprocation history before they decided whether or not to invest. On some trials, we induced a social context by telling the participant that the trustee would later learn how much the participant sampled (\"overt sampling\"). Participants sampled less when there was a monetary cost and when the reciprocation history was more conclusive. Crucially, when sampling was free and overt, participants sampled less, suggesting negative consequences of appearing suspicious. In post-experiment questionnaires, participants indeed reported a belief that the reciprocation probability would decrease when information was overtly sampled. The findings replicated in a second experiment and were well accounted for by a utility-maximizing model in which overt sampling induces a decrease in reciprocation probability. This study opens the door to broader applications of the tools and models of information sampling to social decision-making.\n\nSignificance StatementTrust and reciprocity are essential for establishing and maintaining beneficial cooperative interactions. However, not everyone can be trusted. Here, we focus on a fundamental question in the study of social interaction: how people gather and use information to make a decision to trust or not trust. While more information seems better, participants gathered less information about trustworthiness when the trustee would learn about the inquiries, as if they avoided appearing suspicious. Indeed, participants reported that they believed that sampling elaborately would make the trustee less willing to reciprocate trust. Using a mathematical model of information gathering, we show that this belief indeed reduces the value of information. Our findings contribute to a deeper understanding of information gathering in social contexts.

neuroscience↗