Most habitats in nature are heterogeneous, incorporating favorable and unfavorable microhabitats for different animals, based on their ecological niche. Unsuitable microhabitats have negative consequences for individual growth and survival. Animals, therefore, should fine-tune their location within the habitat by dispersing away from such microhabitats. We studied the suitability of different constant microhabitat conditions for wormlion larvae, a trap-building predator, tested in groups under laboratory conditions. Wormlions construct pit-traps in loose soil and capture small arthropod prey. As wormlions occur in high densities in nature, testing in groups is thus more indicative of their natural behavior than testing individuals. Wormlions responded strongly to biotic conditions—high conspecific density, starvation, and large body mass of conspecifics—by either increasing pit-relocation events or moving away from the microhabitat center to the periphery of the arena, probably opting for a way out. In other instances, individuals increased their distance to the nearest neighbor, thereby changing the spatial pattern toward a more regular pattern, potentially indicating interference competition. The only abiotic condition apparently perceived by wormlions as unsuitable was shallow sand, which led to frequent relocations. The two other abiotic factors—illumination and sand particle size—had no observable effect on behavior, although wormlions in nature always occur under shade in fine sand, and prefer both shade and fine sand particle size under laboratory conditions when given a choice. Under the fine spatial scale of the present experiment, biotic factors appear to be more influential than abiotic ones.

Background:No study has examined the performance of emergency department (ED) nurses in establishing intraosseous access (IO) access. This study aimed to evaluate ED nurses' success rate in establishing pediatric IO access using semiautomatic devices. Methods:A randomized crossover simulation study was conducted. The success rates of ED nurses were compared with those of paramedics with similar years of experience. The study instruments were the new springloaded injector (NIO) and the battery power drill (EZ-IO). Uncooked piglets' bones were used as the study model. All attempts were filmed by a video camera. Successful placement was defined as the visualization of flow from the marrow cavity. Participants recorded their ranking of the "ease of use" of each device.Results: No differences in 1-attempt success rate was found between nurses and paramedics (27/34 [79.4%] vs 25/30 [83.3%], P = 0.68). Nurses and paramedics had similar success rates with the 2 semiautomatic IO devices (12/17 vs 12/15 with the spring-loaded injector, P = 0.69, and 15/17 vs 13/15 with the battery power drill, P = 0.9). The number of failed attempts and the causes for failure were equally distributed between nurses and paramedics. Median ease-of-use Likert-scale scores of the springloaded injector and the battery power drill were 4 (interquartile range [IQR] = 3-4) and 5 (IQR = 5-5) (P < 0.04) for the nurses and 5 (IQR = 4-5) and 5 (IQR = 4-5) (P = 0.44) for the paramedics, respectively.Conclusions: Emergency department nurses and paramedics had a similarly high insertion success rates on a pediatric bone model. This pilot study suggests that ED nurses can successfully perform this procedure.