Insects are able to navigate their environments because they can detect hydrocarbons and volatile odors, but it is not clear which one has the fastest reaction when detected, or how much of a response can be produced due to either one. In order to determine which category of odorant is detected first as well as which one causes the highest response rate, data on electrophysiological responses from ants was analyzed. While the statistical tests can be done to understand and answer the questions raised by the study, there are various hydrocarbons and volatile odors that were not used in the data. Conclusive evidence only applies to the odorants used in the experiments.
One of the identified health risk areas for human spaceflight is infectious disease, particularly involving environmental microorganisms already found on the International Space Station (ISS). In particular, bacteria belonging to the Burkholderia cepacia complex (Bcc) which can cause human disease in those who are immunocompromised, have been identified in the ISS water supply. This present study characterized the effect of spaceflight analog culture conditions on Bcc to certain physiological stresses (acid and thermal as well as intracellular survival in U927 human macrophage cells). The NASA-designed Rotating Wall Vessel (RWV) bioreactor was used as the spaceflight analogue culture system in these studies to grow Bcc bacterial cells under Low Shear Modeled Microgravity (LSMMG) conditions. Results show that LSMMG culture increased the resistance of Bcc to both acid and thermal stressors, but did not alter phagocytic uptake in 2-D monolayers of human monocytes.
Although social hierarchies are commonly found all throughout nature, the underlying mechanisms of their formation are still ambiguous. Hierarchies form through a wide range of interactions between subordinate and dominant individuals, and the ponerine ant Harpegnathos saltator provides the perfect model to explore such dominance behaviors. When the queen is absent or her fecundity levels drop below a certain threshold, H. saltator workers undergo a dominance tournament, in which several individuals emerge as gamergates, reproductive workers that are not queens. During this tournament, several characterizable dominance behaviors are exhibited (antennal dueling, dominance biting, and policing), which can be used to study the behavioral and social dynamics in the formation of a reproductive hierarchy. Colonies of 15, 30, 60, and 120 workers were created in duplicate, and their dominance tournaments were recorded to study how these interactions impact gamergate establishment. Rather than studying these behaviors as isolated incidents, responses to policing behaviors (timid, neutral, or aggressive) and their duration were recorded along with the frequency of dueling. Three groups were determined: dueling future gamergates (DFG), dueling future non-gamergates (DFNG) and non-dueling individuals (ND). DFNG received many more policing attacks and the duration of these interactions lasted much longer. DFG consistently exhibited the most dueling. Timid and neutral responses were more common than aggressive responses, perhaps due to energy conversation purposes. Peaks in dueling correspond to peaks in policing, highlighting the dynamic behavioral interactions necessary for the formation of a reproductive hierarchy.