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Detection of a present predator is critical for prey survival, but prey cannot remain constantly vigilant without suffering fitness costs. To reduce the costs of vigilance, prey species use different cues to determine if another animal is a predator. We wished to determine whether or not Pelegrina helenae would respond to digital images of Phidippus audax as predators and whether the size of an image played a role in predator recognition response. P. helenae were placed in a plastic enclosure facing an iPhone X and shown an image of either P. audax or a ladybug and trials were recorded using a GoPro Hero 7. A second experiment was then performed where spiders were shown the same stimuli, but all ladybug stimuli had been increased to match the size of the P. audax stimuli. The presence of a Phidippus audax stimulus on screen significantly increased the vigilance duration of Pelegrina helenae which indicates that there is some specific visual predator cue that P. helenae is using to identify P. audax as a predator. Size on an image was not significant in the global model, but in the artificial size model, the vigilance duration between P. audax and the ladybug stimulus was not significantly different, indicating that size does play some role in predation risk, but not a large enough role to override specific predator cues.

Stable isotope analysis of δ15N and δ13C values allow us to interpret the effects of interspecific competition and environmental factors on fishes’ resource use. Saratoga Lake in Wyoming is one of the few locations brook stickleback Culaea inconstans (an invasive species), Iowa darter Etheostoma exile (a species of greatest conservation need), and fathead minnows Pimphales promelas are present. We used stable isotope signatures to investigate the trophic patterns of these species as well as catch rates over time. We sampled Saratoga Lake six times from June through September 2021. Fifteen individuals per species were harvested at each sampling event for stable isotope analysis and the remaining fish were identified, measured, and enumerated. Trends in δ13C data suggest that brook stickleback and fathead minnow exploited pelagic resources while Iowa darter primarily used littoral resources early in the season. However, brook stickleback and fathead minnow switched to use more littoral resources later in the season, coinciding with the timing of a cyanobacterial bloom. Iowa darter catch rate steadily declined over the season while fathead minnow and brook stickleback catch rates did not show directional trends. These results imply that changing habitat conditions and resource availability may potentially increase interspecific competition later in the season, with implications for fish species of greatest conservation need. Furthermore, our findings open the door to further investigation of the effects of cyanobacterial blooms on small-bodied fishes.