Date of Award
Honors College Thesis
Donald Yee, Ph.D.
With the increase of global temperature and human populations, prevalence of vector-borne diseases is becoming an issue for public health. Over the years these vectors have been notorious for developing resistance to human regulated insecticides. Thus, other forms of control, including the use of natural predators, have become an important topic in research. Research on member of the family of predaceous diving beetles (Dytiscidae) and their predatory ability to decrease aquatic mosquito larvae populations has been of recent interest. The purpose of this study is to 1) quantify consumption rates of the dytiscid Laccophilus fasciatus rufus juvenile and adults on Culex quinquefasciatus and 2) to test adult dytiscid prey preference between living and dead prey. For study 1, based on morphological differences between life stages and the energy requirements of growth for juvenile stages, I predicted that the juvenile stage of L. f. rufus would consume prey at a faster rates than adults, and for study 2, I predicted that when given the choice to scavenge dead prey or to attack living prey adult dytiscids will prefer to scavenge as a primary means of consumption.
For the consumption trials, nine aquaria were used each crossed with different densities of early or late stage mosquitoes and different densities of plants. To test prey preference, different prey treatments were used including 10 dead, 10 living, a combination of 10 dead and 10 living prey. In experiment 1, there was a significant effect of predator stage by prey stage where the adults consumed later instars at a faster rate than the juvenile dytiscids. In experiment 2, adult dytiscids ate three times as many dead versus living mosquito larvae. Studying these interactions will improve our understanding of the effect of predation of predaceous diving beetles on mosquito populations under natural circumstances.
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Bofill, Carmen E., "Differences in consumption rates between juvenile and adult Laccophilus fasciatus rufus (Coleoptera: Dytiscidae) on larval Culex quinquefasciatus (Diptera: Culicidae)" (2014). Honors Theses. 254.