O dimorfismo sexual nas espécies pode surgir a partir da seleção decorrente dos diferentes sistemas reprodutivos. Estudos comportamentais de espécies neotropicais são raros e pouco se sabe sobe as espécies brasileiras. Neste estudo, foram descritos o comportamento de três espécies neotropicais que ocorrem no Cerrado brasileiro: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) e Heaterina rosea (Calopterygidae). Também foi evidenciado o dimorfismo sexual nestas espécies e investigou-se a partir de observações comportamentais, como o dimorfismo se desenvolve em espécies com diferentes táticas reprodutivas. Com os resultados obtidos, vemos que em espécies territoriais os machos são maiores do que as fêmeas, enquanto em espécies não-territoriais as fêmeas são maiores do que os machos. Sugere-se que, diferentemente de outros estudos, em Zygoptera o tipo de sistema reprodutivo pode determinar o dimorfismo sexual. / Sexual size dimorphism (SSD) can in some species result from the selection acting through different mating systems. Behavioral studies of neotropical species are rare, and few is known about the brazilian species. In this study, we described the behavior of three neotropical species that occur in the brazilian neotropical savannah: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) and Heaterina rosea (Calopterygidae). We show the SSD in these species and investigates through behavioral observations, how SSD develops in species with different mating tactics. With our results, we can see that in territorial species the males are larger than females, while in non-territorial species the females are larger than males. We suggest that, unlike other studies, in Zygoptera the kind of mating system adopted by males may determinate the SSD in a species.

O dimorfismo sexual nas espécies pode surgir a partir da seleção decorrente dos diferentes sistemas reprodutivos. Estudos comportamentais de espécies neotropicais são raros e pouco se sabe sobe as espécies brasileiras. Neste estudo, foram descritos o comportamento de três espécies neotropicais que ocorrem no Cerrado brasileiro: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) e Heaterina rosea (Calopterygidae). Também foi evidenciado o dimorfismo sexual nestas espécies e investigou-se a partir de observações comportamentais, como o dimorfismo se desenvolve em espécies com diferentes táticas reprodutivas. Com os resultados obtidos, vemos que em espécies territoriais os machos são maiores do que as fêmeas, enquanto em espécies não-territoriais as fêmeas são maiores do que os machos. Sugere-se que, diferentemente de outros estudos, em Zygoptera o tipo de sistema reprodutivo pode determinar o dimorfismo sexual. / Sexual size dimorphism (SSD) can in some species result from the selection acting through different mating systems. Behavioral studies of neotropical species are rare, and few is known about the brazilian species. In this study, we described the behavior of three neotropical species that occur in the brazilian neotropical savannah: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) and Heaterina rosea (Calopterygidae). We show the SSD in these species and investigates through behavioral observations, how SSD develops in species with different mating tactics. With our results, we can see that in territorial species the males are larger than females, while in non-territorial species the females are larger than males. We suggest that, unlike other studies, in Zygoptera the kind of mating system adopted by males may determinate the SSD in a species.

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.

A functional understanding of how phenotypic traits may affect growth, reproduction and survival is necessary to understand their ecological and evolutionary consequences. Larval dragonflies (Odonata: Anisoptera) swim using jet propulsion, likely controlled by abdominal traits and perhaps to escape fish predators. I investigated whether abdominal morphology explains swimming performance and if either explains the distribution of larvae among ponds that vary in predation risk. I recorded and measured the swimming performance of dragonflies responding to simulated attack and tested relationships with abdominal traits expected to influence jet thrust force generation. Variation in swimming performance was explained by abdomen dry weight, ventral surface area, and abdominal segment 10 width across genera as hypothesized. High-performance dragonflies were more likely to occur in ponds containing predatory fish. This is the first investigation of the morphology responsible for jet propulsion, and the relationship between swimming performance and larval dragonfly ecology.

Freshwater ecosystems in south-western Australia have been extensively altered over the last two centuries as a result of human activities. The effect this has had on aquatic fauna, particularly invertebrates, is largely unknown because of inadequate knowledge of the pre-existing fauna. Future changes in the composition of aquatic fauna will also go undetected unless current distributions of existing species are well documented. This thesis addresses the problem by investigating the current distributions and conservation status of aquatic insects in south-western Australia from three orders: Odonata, Plecoptera and Trichoptera. Extensive distributional data was collected by identifying larval specimens from a large number of samples collected throughout the south-west as part of an Australia-wide macroinvertebrate bioassessment project. In addition, a database created from a species-level biological study of the wheatbelt region of Western Australia was utilised, and previously published records of occurrence for species within the south-west were compiled. These results were then used to assess the conservation status of each species using the IUCN red list criteria. Environmental parameters measured at time of sampling were also examined using logistic regression to determine which factors are important in influencing the distributions of aquatic insects in south-western Australia. The conservation value of sites based on Odonata, Plecoptera and Trichoptera compositions was also determined and the degree of protection provided for sites of high conservation value investigated.The high rainfall forested region of the south-west was found to be important for a large number of species, including the majority of those found to be rare and/or restricted. Overall, 37% of species were found to be threatened, with the Trichoptera containing both the greatest number and highest proportion of threatened species. Logistic regression results generally agreed with the distributions obtained for each species, with rainfall and other parameters indicative of streams in the headwaters of forested catchments being positively associated with species found to be restricted to the high rainfall region. Two parameters known to be affected by human disturbance in the south-west, conductivity and nutrient concentrations, were found to be important in determining the occurrence of many species and this could have important consequences for aquatic insect conservation. Widespread species occurring within the low rainfall region of the south-west did not show as many significant relationships to measured environmental parameters, possibly due to their greater ecological tolerances and adaptations which allow them to persist in a low rainfall environment. The implications of results are discussed, and recommendations for the conservation and management of aquatic insects in south-western Australia are given.

The thesis explores various aspects of ecology of endangered damselfly Coenagrion ornatum, the specialists for lowland headwaters, in post-mining streams of Radovesicka spoil. The first part of thesis is manuscript which has been already submitted in Journal of Insect Conservation. In the first part, we focused on population estimate of the local population using capture-recapture method, and explored its habitat requirements across life stages and spatial scales. In the next part, I assess mobility of the focal species and reveals basic distribution patterns. Finally, the thesis suggest various implications for restoration of post-mining freshwaters and conservation of the studied species.

Tropical rain forests around the world suffer from deforestation, which is caused mainly by small-scale farmers. These farmers largely employ slash-and-burn methods to clear the land for agricultural settlement. Agroforestry systems are widely found in the humid tropics, where they could have great potential to increase the productivity of farming systems and sustain continuous crop production and they are also supposed to conserve biodiversity. As a group of freshwater invertebrates, dragonflies (Odonata) are commonly used as ecological indicators of freshwater ecosystems. The main objective of the study is to assess the impact of land use changes on dragonflies (Odonata) species richness and diversity, namely primary and secondary forest, cocoa agroforest and slash-and-burn agriculture in the Tropical Africa. We hypothesize, that the species richness and diversity of dragonflies decrease with disturbance of the ecosystems, along the land-use changes gradient.

This study is about how biomass of dragonflies insects have changed over the past 20-years in a forested area of central Sweden. This was done by analysing previously collected Odonata larvae stored in ethanol where sampling effort corrects the weight per locality. The results display a small but significant biomass increase over past decades, going against the recently observed trend of biomass decline in insects. However, this biomass gain was not even between the families, the ones that increased the most was Aesnidae and Libelluidae.  The reasons for the observed increase are discussed, some possible suggestions are less disturbance in their environments and their ability to adapt due to their long evolution giving them a phenotypical advantage.

Urbanization involves the conversion of natural areas to impervious surfaces, which can lead to an increase in the frequency and severity of flood events in cities. To mitigate flood risk, stormwater ponds are constructed to manage urban runoff. Stormwater ponds can also be colonized by wildlife, but their suitability as habitat is disputed due to potential toxicological risks. This study assessed the suitability of stormwater ponds as habitat for the bioindicators Odonata (dragonflies and damselflies) and determined environmental factors that impact their community structure. Odonata (adults, nymphs and exuviae) were sampled at 41 stormwater ponds and 10 natural reference ponds across the National Capital Region of Canada, with a subset of ponds sampled over four years (2015-2018). Plant communities, water quality and surrounding land cover were analyzed at each pond to determine their impacts on Odonata community structure. Overall, stormwater ponds had lower Odonata abundance and a greater variation in species richness and community structure compared to natural ponds but had comparable dragonfly reproduction rates. Plants were the most significant driver of Odonata communities, as stormwater ponds with a high richness of native wetland plants had higher Odonata abundance and community structures similar to natural ponds. Water quality was the second most important driver of Odonata communities with dragonflies showing greater sensitivity to urban contaminants than damselflies. While stormwater ponds had higher concentrations of trace elements than natural ponds (e.g. Ni, V, As), concentrations were generally below toxic levels for all elements except copper and chloride, the latter likely an input from winter road salting. Surrounding land cover was the least important factor affecting Odonata communities. In conclusion, this research demonstrated the importance of local-scale factors related to plants and water quality in sustaining Odonata communities and specifies recommendations for stormwater pond design and maintenance that enhance urban biodiversity.

Climate change might affect the distribution of species; therefore, it is important to anticipate the imminent impact of climate change. Even though climate responses have the potential to affect species interactions, most models on the effect of climate change on species distribution assume that species respond to climate individually. Hence studies on competition effects are needed. In this study, I estimated growth, mortality, and behaviour (prey capture success, activity, exploration and boldness) at 20° C and 23° C at intra- and interspecific competition conditions in larvae of a native and a northward dispersing dragonfly. The results showed that the northward expanding Sympetrum fonscolombii had a higher growth and survival rate compared to the native Sympetrum vulgatum at interspecific conditions. At intraspecific conditions the results showed that temperature had no significant effect on the performance of S. fonscolombii, but S. vulgatum showed both a higher growth rate and a higher mortality at 23 ° C. A significant difference between temperatures within prey capture success rate was found in S. vulgatum only, during the second observation period. There was a correlation between activity and exploration in both species, between prey capture success rate and activity during the third observation round in S. vulgatum, and between prey capture success rate and boldness during the first observation round in S. fonscolombii. No other behaviours were correlated. Prey capture success rate was shown to be repeatable in both species, while boldness was repeatable in S. vulgatum only. The behavioural results suggests that behavioural traits are relatively plastic over ontogeny in both species, possibly caused by behavioural variation within each instar. Additionally, boldness, but not activity and exploration, might aid S. fonscolombii in their northward expansion. The majority of these results were similar at both temperatures and indicate that S. fonscolombii has a higher capacity to tolerate climate change, and their presence might negatively impact the performance of S. vulgatum.