Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 73-78).

A population of weed-dwelling damselfly larvae (Enallagma boreale) in Marion Lake, British Columbia was sampled at regular intervals from June 30, 1962 to July 28, 1970 for the purpose of obtaining information regarding life cycle and feeding habits. The larvae sampled were measured, and their gut contents were determined. The Marion Lake population was found to consist of two overlapping, univoltine generations whose cycles differed by about two months. Adults have a long flight period in the summer, and larvae overwinter in mid-larval instars. The food of the larvae consisted mainly of Cladocera and larval Chironomidae, although many types of prey were eaten. Cannibalism was not prevalent in the population. The amount and type of food eaten varied both throughout the year and within different habitats in the lake. It appears that the larvae feed predominantly during the daylight hours. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Thesis (M.Sc.)--Acadia University, 2001. / Includes bibliographical references (leaves 104-121). Also available on the Internet via the World Wide Web.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 165-178). Also available in electronic format on the Internet.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 128-140). Also available in electronic format on the Internet.

The south-central United States serves as an important biogeographical link and dispersal corridor between Nearctic and Neotropical elements of western hemisphere odonate faunas. Its species are reasonably well known because of substantial collections, but there has been no concerted effort to document the extent of biodiversity and possible geographic affinities of dragonflies and damselflies of this region. The recent discoveries of Argia leonorae Garrison, Gomphus gonzalezi Dunkle and Erpetogomphus heterodon Garrison from southern and western Texas and northern Mexico suggest that Odonata species remain to be discovered in this area, particularly from far south Texas and northern Mexico. I have documented a total of 12,515 records of Odonata found in 408 counties within the south-central U.S. A total of 73 species of damselflies and 160 species of dragonflies was revealed in the region. The 233 (197 in Texas) Odonata species are distributed among 10 families and 66 genera. Illustrated family, generic, and species-level keys are provided. Since the beginning of this work in the Fall of 1993, one species has been added each to the Louisiana and Oklahoma faunas, and 12 species have been added, previously unreported from Texas, including four new to the U.S. The area of highest Odonata biodiversity overall (161 spp.) is in the Austroriparian biotic province. The greatest degree of faunal similarity between the south-central U.S. and other intra-continental regions was observed for the eastern (64%) United States. Diversity is a function of area, and as expected, the numbers of breeding birds and Odonata, in each contiguous U.S. state are positively correlated (r=0.376, n=33, p=0.031). There is, however, no strong correlation between land area and species diversity within the region, but those natural biotic provinces (Austroriparian, Texan, Balconian) where aquatic systems and topographic heterogeneity are the greatest provide a broader spectrum of potential Odonata habitats and thus support a greater number of Odonata species.

Heterogeneous environments play an important role in the evolution of traits when selection is diversifying between different conditions. One response is the capacity of individuals to beneficially adjust their phenotype to local conditions, such as different predators. In larval Enallagma damselflies, diversifying selection from predatory dragonfly larvae or predatory fish favours opposing traits, respectively high or low levels of activity, and so appears to drive the adaptive divergence of anti-predator specialists. However, little work has addressed: i) if anti-predator generalist species exist; ii) if anti-predator generalist species express adaptive flexible behaviour; iii) if adaptive flexible behaviour is influenced by prior experience with predators. I compared individual larval behaviour in the presence of fish, dragonfly larvae, or no predators, in four Enallagma species groups from ponds with and without fish predators. Ecological distributions suggest variation in degree of anti-predator generalization, and this was associated with increased responsiveness to predator treatment in the most likely ecological generalist. Responses to predators varied across different behaviours and sometimes were shaped by prior predation experience. Thus, a variety of adaptive strategies may have evolved to cope with heterogeneity in predation risk in larval damselflies. / NSERC, OGS

Concentrations of herbicides in our aquatic ecosystems increase more and more. Among these, the herbicide glyphosate is the most common one. This ecotoxicological study was performed in order to examine the toxic effect of the herbicide glyphosate on aquatic invertebrates. Odonata were selected as study organisms in order to serve as bio-indicators of environmental contamination. Two populations, each of two species (Erythromma najas and Libellula quadrimaculata) were collected from four different locations, to study inter-specific differences, as well as, differences among populations within a species, in response to herbicide exposure. The experiment was conducted for 15 days in a 2 x 4 factorial design with 4 replicates (n = 32). The most common brand of weed-killer ‘Roundup’ containing 7.2 gL-1 of glyphosate) was used as source of glyphosate. Glyphosate was applied at a concentration of 7.6 mgL-1 in the experiment equalling the high end of environmentally relevant concentrations of glyphosate present in contaminated shallow waters. Response variables measured were larval survival, growth and activity. The results showed that glyphosate exposure reduced the survival of the larvae, but the magnitude of the glyphosate effects depended on species identity of the larvae and varied also with population within species. This study clearly shows that herbicide effects on invertebrate fitness depends on species identity and may even vary within species from different populations, possibly due to evolved resistance of random genetic variations between populations or due to random genetic variation between populations.

To identify and quantify the influence of physico-chemical, biotic and geographic factors on the population of dragonflies (Odonata) is an essential tool for research of their ecology. The aim of this study was to 1) assess how these factors influence species richness, diversity and spatial distribution of dragonflies in 42 newly constructed or renewed pools located in the Kokořínsko Protected Landscape Area, which is characterized by two valleys of Liběchovka and Pšovka creeks, low human impact, and a great diversity of small water bodies and 2) use laboratory experiments in order to estimate the relationship between large predatory invertebrates of these pools (Aeshna cyanea, Coenagrion puella, Chaoborus crystallinus and Notonecta glauca) and their common prey (Daphnia curvirostris) in an artificial environment with or without aquatic macrophytes. The pools were monitored and sampled between years 2005 and 2006. In total, 23 dragonflies species were found inhabiting these lentic habitats, comprising 11 species belonging to the suborder Zygoptera and 12 species belonging to the suborder Anisoptera, including a rare species Sympetrum depressiusculum (larvae). Most variability in the dragonfly species richness was explained by the size of the water surface area, followed by the location of the pools (inside...