Publication Date


Document Type


First Advisor

Ende, Carl von

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences


Calopteryx maculata--Larvae--Behavior; Calopterygidae--Larvae--Behavior; Odonata--Larvae--Behavior


Damselflies of the genus Calopteryx (Odonata: Calopterygidae) are common in stream systems, but few investigations have examined the behavior of the larvae under different habitat conditions. I studied the effects of shade and the diel cycle on larval activity when a vertebrate (Semotilus atromaculatus) and an invertebrate predator (Aeshna umbrosa) were present or absent. Experiment 1 was designed to determine whether the calopterygid larvae used shaded or unshaded regions of aquaria when in the presence/absence of predators. In Experiment 2 ,1 examined frequency of larval movement when the calopterygids were in shaded and unshaded aquaria, with and without predators. I conducted Experiment 3 to examine whether red light could be used for the nighttime observations of the larvae. The activity of the larvae was compared when exposed to constant and pulsed red or white light. In Experiment 4 ,1 compared activity patterns of the larvae during the day and at night when in aquaria with and without predators. The calopterygids preferred the shaded regions of the aquaria 96% of the time in Experiment 1. However, when fish were present in the shade, the calopterygids used the shaded areas less (68%). Despite the preference for shade found in Experiment 1, the frequency of moves by the damselfly larvae did not differ significantly between the shaded and unshaded aquaria, regardless of predator presence or absence. The larvae moved significantly less under constant red light than in complete darkness (control). Because the movement under pulsed red light was not different from the control, the former was used for observations in Experiment 4. The calopterygid larvae activity corresponded to the experimental diel pattern in Experiment 4: the larvae moved infrequently during the day (28% of observations) compared to the nighttime (94%). Again, this activity was unaffected by the presence or absence of predators. Calopteryx maculata larvae live in habitats where predators are ubiquitous, and the presence/absence of predators does not effect the ?hard-wired? activity patterns of the calopterygids, regardless of shade or time of day.


Includes bibliographical references (pages [65]-74).


vi, 74 pages




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