TEMPERATURE , RESOURCE INPUT , AND STANDING GENETIC VARIATION AFFECT PREDATOR RESPONSES OF PHYSA ACUTA

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Katherine E. Gordon (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: In urban areas , features such as high percentages of impervious ground cover , patchiness , and storm water runoff can lead to increases in temperature and external nutrient input into aquatic systems. Such factors can lead to changes in primary productivity , and thus the growth rates of primary consumers , as well as the vulnerability of primary consumers to predation. Additionally , isolated populations due to patchiness of natural areas in urban environments can lead to inbred populations , which can also influence growth rates and vulnerability of primary consumers. To assess how such factors can influence interspecific interactions , we test how temperature , resource availability , and standing genetic variation of the freshwater snail Physa acuta affects the snail's anti-predator responses and life history characteristics. We conducted an experiment in which we reared snails from inbred or wild-caught lineages at high or low temperatures , with high and low resource inputs , and with or without chemical cues of crayfish (Procambarus clarkii) predation. We assessed how these treatments affected predator avoidance behavior , anti-predator morphological responses , reproductive output , and survival. We found that snails reared in high temperatures , and with low resource availability were unable to exhibit typical morphological responses to predators. We also found that snails were more likely to exhibit anti-predator behaviors when resource availability was low and when temperatures were high , and that behavioral responses to predators were higher for inbred snails than wild-caught snails. Snail survival was significantly affected by temperature , resource availability , and standing genetic variation. Reproductive output of snails was also affected by temperature , resource availability , predator cue presence , and standing genetic variation. These results indicate that features common in urban systems can influence not only individuals' ability to persist in these environments , but also can have effects on species interactions in ways that can cascade through food webs and potentially change ecosystem functions.

Additional Information

Publication

Thesis

Language: English

Date: 2019

Keywords

Behavioral Avoidance, Phenotypic Plasticity, Physa acuta, Resource Availability

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