Food competition mechanism between Solenopsis invicta Buren and Tapinoma melanocephalum Fabricius

This study compared the amount of food resource depletion and interference competition at the individual and colony levels between Solenopsis invicta and Tapinoma melanocephalum laboratory colonies. The consumption of sausage, honey water, and mealworm by S. invicta colonies of equal worker number was higher than that by T. melanocephalum colonies. The consumption of sausage and honey water by S. invicta colonies of equal worker number was significantly higher than that by T. melanocephalum colonies. However, the amounts of sausage, honey water, and mealworm depleted by S. invicta colonies of equal worker biomass were lower than those depleted by T. melanocephalum colonies. The consumption of sausage and mealworm by S. invicta colonies of equal worker biomass were also significantly lower than that by T. melanocephalum colonies. Individual-level interference competition between S. invicta and T. melanocephalum colonies in limited space was intense. Competition intensity and the death rate reached their maximum when the worker numbers of both colonies were equal. In any proportion, the death rate of T. melanocephalum reached over 80%, higher than that of S. invicta.S. invicta colonies of equal worker biomass and equal worker number recruited more workers for colony-level interference competition and used more resources. However, the death rates among S. invicta colonies were higher than those among T. melanocephalum colonies. The active resource plundering of S. invicta reflected their intense competitiveness and limited the range of activity of T. melanocephalum.

Association between functional network connectivity, retina structure and microvasculature, and visual performance in patients after thalamic stroke: An exploratory multi‐modality study

Abstract Background and objective Neuro‐ophthalmologic symptoms and retinal changes have been increasingly observed following thalamic stroke, and there is mounting evidence indicating distinct alterations occurring in the vision‐related functional network. However, the intrinsic correlations between these changes are not yet fully understood. Our objective was to explore the altered patterns of functional network connectivity and retina parameters, and their correlations with visual performance in patients with thalamic stroke. Methods We utilized resting‐state functional MRI to obtain multi‐modular functional connectivity (FC), and optical coherence tomography‐angiography to measure various retina parameters, such as the retinal nerve fiber layer (RNFL), ganglion cell‐inner plexiform layer (GCIPL), superficial vascular complex (SVC), and deep vascular complex. Visual acuity (VA) was used as a metric for visual performance. Results We included 46 patients with first‐ever unilateral thalamic stroke (mean age 59.74 ± 10.02 years, 33 males). Significant associations were found between FC of attention‐to‐default mode and SVC, RNFL, and GCIPL, as well as between FC of attention‐to‐visual and RNFL (p < .05). Both RNFL and GCIPL exhibited significant associations with FC of visual‐to‐visual (p < .05). Only GCIPL showed an association with VA (p = .038). Stratified analysis based on a disease duration of 6 months revealed distinct and significant linking patterns in multi‐modular FC and specific retina parameters, with varying correlations with VA in each subgroup. Conclusion These findings provide valuable insight into the neural basis of the associations between brain network dysfunction and impaired visual performance in patients with thalamic stroke. Our novel findings have the potential to inform future targeted and individualized therapies. However, further comprehensive studies are necessary to validate our results