Infestation by Octolasmis species (Lepadiformes, Poecilasmatidae) of the marine crab Lupocycloporus gracilimanus (Decapoda, Portunidae) from India

The portunid crab Lupocycloporus gracilimanus from Digha, Bay of Bengal, India was investigated for an infestation by the lepadomorph cirriped Octolasmis spp. About 93% of the epibionts examined were found attached to the surface of the carapace, abdomen and legs, and these were identified as Octolasmis warwicki (EOW). Only 7% of the epibionts were attached to the branchial lamellae, and these were identified as Octolasmis angulata (EOA). Twenty-seven O. warwicki were also found to have conspecific dwarf males (CDM) attached to the scutum: probably an adaptive strategy to maximize the total insemination. Both the epibionts and the CDM showed spatial preference for the posterior mesobranchial region of the carapace. Most of the CDM (27%) were seen as a single attachment on the epibiont. The distance between the epibiont and its nearest neighbour (DNN) was found to be strongly and negatively correlated (, ) with the number of epibionts, indicating its preference to stay in an intermediate-sized group rather than remain solitary, which probably would have facilitated the evolution of dwarf males (CDMs). A higher percentage of epibionts were observed to have attached CDMs when the DNN increased, and above the 25 mm DNN, all epibionts were having CDM attachments, which is believed to be a strategy to maximize the fertilization success of CDMs by reducing sperm competition. A strong, positive correlation (, ) was observed between the carapace width of the host crab and the numbers of the infesting epibionts, proving that the larger crabs are more susceptible to the infestation compared to the smaller ones. The sex ratio of the host crab was 1 : 5.5 (Male : Female), nevertheless, only the females were infested by the epibionts. The percentage of the prevalence, relative abundance and mean intensity of EOW infestation were recorded as 46.15%, 182.05% and 394.44%, respectively. None of the crabs had serious external or internal infestations that seemed to hinder the activities of the animal. This is the first report of the infestation of these Octolasmis species on the portunid crab Lupocycloporus gracilimanus from India.

Residents’ Spatial Preference for Urban Forest Park Route during Physical Activities

Urban parks positively affect the life quality and health of urban residents as well as the environment where they live. When it comes to the design of a future urban forest park, it is necessary to consider the protection of ecological environment, landscape sustainability and practicability. This study explored residents’ spatial preference for urban forest parks based on preference survey data. According to the rating scores obtained for four urban forest park routes during physical activities, this study used cognitive maps and multinomial logit models to figure out the potential influencing factors affecting residents’ spatial preference while they engage in physical activities. The results suggest that forest routes are still the primary choice for urban residents. Although familiarity with the spatial image preference for urban forest parks varied from person to person, residents’ choice of route shows certain commonalities, which was reflected in the sequential cognitive maps obtained from them. In addition, residents’ route preference is influenced by their exercise habits, environmental preference and residential location. There is also a certain correlation between residents’ preference and their characteristics. This study provides additional information for planners, developers, engineers, architects and foresters in building a more suitable environment that is aesthetically appealing and ecologically sound for physical exercising.

How Does Uncertainty Affect Voters' Preferences?

Rational voters care about outcomes, while parties campaign on policy proposals, the outcomes of which are never perfectly known. Can parties exploit this uncertainty to shape public opinion? This article presents a spatial preference model for policy proposals with uncertain outcomes. It reports the results of a large pre-registered survey experiment that involved presenting respondents with predictions about the effects of three policy proposals. The findings show that respondents update their attitudes to the proposals as their beliefs about outcomes change, and that parties are no less able to influence beliefs than non-partisan experts. Contrary to previous research, respondents discount outcome uncertainty by giving equal weight to conflicting optimistic and pessimistic predictions. The study shows that parties can shape public opinion by influencing voter beliefs, and that voters are not repelled by the uncertainty inherent in conflicting information.

Distinct oligodendrocyte populations have spatial preference and different responses to spinal cord injury

Mature oligodendrocytes (MOLs) show transcriptional heterogeneity, the functional consequences of which are unclear. MOL heterogeneity might correlate with the local environment or their interactions with different neuron types. Here, we show that distinct MOL populations have spatial preference in the mammalian central nervous system (CNS). We found that MOL type 2 (MOL2) is enriched in the spinal cord when compared to the brain, while MOL types 5 and 6 (MOL5/6) increase their contribution to the OL lineage with age in all analyzed regions. MOL2 and MOL5/6 also have distinct spatial preference in the spinal cord regions where motor and sensory tracts run. OL progenitor cells (OPCs) are not specified into distinct MOL populations during development, excluding a major contribution of OPC intrinsic mechanisms determining MOL heterogeneity. In disease, MOL2 and MOL5/6 present different susceptibility during the chronic phase following traumatic spinal cord injury. Our results demonstrate that the distinct MOL populations have different spatial preference and different responses to disease.