Adult Odonates Research Articles

Assessing the response of odonates (dragonflies and damselflies) to a tropical urbanization gradient

Abstract Understanding species responses to urbanization is important to realize their specific conservation needs. Odonates (dragonflies and damselflies) are freshwater insects perceived as good ecological indicators. To investigate responses of tropical odonates to an urbanization gradient, we sampled adult odonates along an urbanization gradient at six sites along the Mula River across Pune City, Maharashtra, India. For species–habitat analysis, we first performed a variable reduction using principal component analysis. we analyzed species–habitat data using redundancy analysis and canonical correspondence analysis. We documented 15 odonates across 6 sites. Our statistical analyses on patterns of odonate assemblages across sites and environmental variables did not return significant results. However, we detected site-exclusivity in a few species based on occurrence data and identified urban sensitive, urban tolerant and generalist species. We found that the odonate diversity was highest at a moderately urbanized site. We believe that increase in diversity due to moderate amounts of disturbance can be explained by the intermediate disturbance hypothesis. Based on our data, we suggest that for the conservation of odonates in the urban context, anthropogenic disturbance needs to be regulated. Here, we demonstrate that understanding species–habitat associations is the first step towards understanding their ecological and conservation requirements. To conserve odonates and rivers in metropolitan cities like Pune, restoring original river-side habitat and reducing the disturbance at highly urbanized sites to at least intermediate levels needs to be done on an urgent basis.

Predation of Dragonfly Nymphs by Passerines

Avian predation of dragonflies and damselflies (Odonata) is fairly well-documented, but most observations are restricted to non-passerine birds eating adult odonates. As nymphal odonates are aquatic, most passerine birds would not encounter them while foraging but instead are more likely to catch teneral adults on their maiden flights. Photographs taken by naturalists over the past several years suggest that passerine predation on odonate nymphs, while apparently rare, occurs across a wider range of species than previously documented.

Can dragonfly and damselfly communities be used as bioindicators of land use intensification?

Abstract There is a growing need to identify efficient biological indicators for assessing accelerated land use intensification, as well for understanding the effects of past environmental changes on species distributions. To address this, we used an extensive opportunistic survey dataset of 254 adult odonate (suborder Anisoptera or dragonflies; suborder Zygoptera or damselflies) species collected in nine Mexican hydrological regions during two time windows (1980–1993 and 1994–2010). We evaluated species richness, body size and individual species’ response to land use intensification over time at a national scale using Phylogenetic Bayesian Regression Mixed Models. We found that dragonfly species serve as good indicators of current land use, whereas damselfly species show time-lagged effects of land use intensification. Large species could thus be used as a proxy of recent reduction of original vegetation, whereas small species provide information on historic habitat modification. Odonate body size seems to be a better variable for measuring the integrity of original vegetation than the more commonly used species richness. Finally, the use of individual species as bioindicators at broad spatial and temporal scales is not encouraged, as it does not reflect the degree of ecological integrity, and only the occurrence of some species combinations can indicate environmental degradation.

The first record of parasitism by Forcipomyia (Diptera: Ceratopogonidae) in Cuban odonates

Several species of biting midges of the genus Forcipomyia are frequently found attached to the wings of adult odonates, acting as parasites by sucking haemolymph from the wing veins. Here we report the first finding of F. incubans on odonates in the peninsula of Zapata, Cuba. We found the midge on the wings of Erythrodiplax simplicicollis, E. umbrata, Crocothemis servilia, and in the wings and body of Perithemis domitia, all species belonging to the family Libellulidae. This is the first record of this interaction for the Antilles.

Appropriate management practices help enhance odonate species richness of small ponds in peri-urban landscapes

Adult odonate biodiversity was investigated to understand their relationship with pond management practices and environmental conditions in a rapidly urbanized landscape. Twenty-four farm ponds in Taoyuan City were selected and classified into five pond groups based on pond management practices. In total, 21 species, 17 genera, and 6 families of odonates were recorded for a total of 5701 individuals between June 2014 and July 2015. The abundance of Odonata was unrelated to pond size or distance to the nearest pond; however, odonate species richness was negatively and significantly correlated with pond size. Pond management practices considerably affected pond aquatic macrophytes and dike construction materials. Ecology park ponds under intense human management and undisturbed ponds without any human management had higher species richness than did the ponds in the other three fish farming groups. Species richness was highest in small and human-modified ponds. By contrast, species richness was lowest in two fish farming pond groups. These results suggest that pond management practices can increase or reduce odonate species richness depending on the alteration of pond microhabitat features. Our observations suggest that the enhanced habitat quality of small ponds provides an opportunity to protect freshwater biodiversity for local governmental civil servants in urbanized landscapes.

Spatial and temporal effects of land use change as potential drivers of odonate community composition but not species richness

Land-use changes and land cover change are drivers of diversity. The effects of such drivers over the temporal trend in species richness and composition, particularly on invertebrate diversity in megadiverse countries, is controversial. One key animal group to clarify this controversy is that of odonate insects (dragonflies and damselflies), given their combined close water-land requirements. We have investigated whether changes in land use impact species richness and composition of odonates from 1980 to 1993 (period I) to 1994–2010 (period II) in Mexico. The effect of land use changes and land cover changes on species richness was analyzed using multiple diversity measures and at different spatial scales. In period II, an area reduction in original vegetation and increase in land use occurred. Responses to land use varied among spatial scales and measures of diversity but, overall, species richness in the transformed area was higher than in the original vegetation. However, species composition indicated a high species turnover inside hydrologic regions (watersheds) and across land uses classes, particularly between original and secondary vegetation. Our interpretation is that despite high land use conversion in Mexico, adult odonates seem resilient to land use change in terms of species richness, but not in species composition, which is in partial agreement with the intermediate disturbance hypothesis. Finally, we suggest that hydrologic region scale and use of entropy maximization (HCDT entropy), could provide a reliable biodiversity estimation of species loss associated with land use change.

Lentic and lotic odonate communities and the factors that influence them in urban versus rural landscapes

Habitat alteration via urbanization has very different effects on even closely related taxa. Most research investigating the ecological effects of urbanization has focused on birds or mammals, resulting in a relatively poor understanding of how the species richness and community composition of invertebrates may change. We quantified differences in species richness of adult odonates (dragonflies and damselflies) at lentic and lotic sites in urban and rural landscapes, and we examined environmental factors that might drive the differences in community composition that we observed. For lotic sites, species richness did not differ between urban versus rural sites for either dragonflies or damselflies. For lentic sites, urban and rural sites contained similar dragonfly species richness, but damselfly species richness was significantly lower at urban sites than at rural sites. Differences in lentic odonate community composition were associated with the amount of urban development within 150 m of each site, mean algal coverage, and distance to the urban center. At lotic sites, water temperature and distance to the urban center were correlated with differences in odonate community composition. The differing responses to urbanization observed in this study were probably a consequence of differences between lentic versus lotic ecosystems and between dragonflies versus damselflies in dispersal capability and habitat specificity. Given that different environmental factors affected these taxa differently in lentic and lotic sites, maintaining the highest level of odonate diversity possible across a landscape will require the use of different management practices for each ecosystem type.

Pellets of proof: First glimpse of the dietary composition of adult odonates as revealed by metabarcoding of feces.

Recent advances in molecular techniques allow us to resolve the diet of unstudied taxa. Odonates are potentially important top‐down regulators of many insects. Yet, to date, our knowledge of odonate prey use is based mainly on limited observations of odonates catching or eating their prey. In this study, we examine the potential use of metabarcoding in establishing the diet of three adult odonate species (Lestes sponsa, Enallagma cyathigerum, and Sympetrum danae) at a site in southwestern Finland. To this purpose, we compared three different methods for extracting DNA from fecal samples: the Macherey‐Nagel Nucleospin XS kit, a traditional salt extraction, and the Zymo Research Fecal Microprep kit. From these extracts, we amplified group‐specific mitochondrial markers (COI and 16S rRNA) from altogether 72 odonate individuals, and compared them to comprehensive reference libraries. The three odonate species show major overlap in diet, with no significant differences between individuals of different size and/or gender, reflecting opportunistic foraging of adult odonates. Of a total of 41 different prey species detected, the most frequently consumed ones were Diptera, with additional records of six other orders. Based on our data, the best DNA extraction method is the traditional salt extraction, as it provides the most information on prey content while also being the most economical. To our knowledge, this is the first study to resolve the species‐level diet of adult odonates. Armed with the appropriate methodological caveats, we are ready to examine the ecological role of odonates in both terrestrial and aquatic food webs, and in transferring subsidies between these two realms.

Trophic ecology of adult male Odonata. I. Dietary niche metrics by foraging guild, species, body size, and location

1. Information on the dietary niches of adult odonates is sparse, as they are highly mobile and evasive animals, which makes them difficult to observe in their natural habitat. Moreover, there is a lack of knowledge on how varying behavioural traits of odonates relate to phenomena like niche partitioning.2. This study investigated niche partitioning amongst odonate species, foraging guilds and size classes in a riverine system in the Eastern Cape province of South Africa. A combination of stable isotope and fatty acid‐based niches was used to infer odonate feeding.3. Both fatty acid and stable isotope‐based niches showed that there was niche separation amongst odonates that forage in flight (fliers) and those that forage from a perch (perchers), amongst odonates of different size classes (damselflies, medium‐ and large‐sized dragonflies), and amongst species, although varying levels of niche overlap were observed in each case.4. Niche sizes of odonates varied between an upstream and a downstream site. Generally greater niche overlap was recorded at the narrow upstream site (associated with low insect emergence rates) than the wider downstream site (associated with high insect emergence rates), indicating that a greater degree of resource sharing occurred at the upstream site where aquatic food was less abundant.5. The findings of this study suggest that dietary niches of odonates can be influenced by foraging guild, body size, and/or environmental conditions, and additional study in a variety of regions is recommended to determine the greater applicability of these findings.

Examination of the link between life stages uncovered the mechanisms by which habitat characteristics affect odonates

AbstractThe larval and adult stages of amphibious animals are affected by both aquatic and terrestrial habitat characteristics, and each stage also affects the other. However, this link between life stages has been largely overlooked in previous studies. We examined the effect of aquatic and terrestrial habitat characteristics on the diversity of larval and adult odonates, taking into account the link between the two life stages. Species diversity of adult and larval odonates and aquatic plants, as well as patterns of land use, was investigated in 63 irrigation ponds. We created structural equation models, with paths from land use and aquatic plants characteristics to larval and adult stages of odonates, as well as between the two stages, and chose the best model based on the lowest Akaike information criterion. Adult odonates, but not larvae, were affected by aquatic and terrestrial habitat characteristics, suggesting that the former is the key stage for odonate communities. We observed a positive relationship between the diversity of aquatic plants and larval odonates, but this was in fact due to the effects of aquatic plants on adults, which carried over to the larval stage. Our study showed that a consideration of the link between life stages is crucial for a complete understanding of the relationship between habitat characteristics and amphibious animal populations.

Effects of human disturbance and riparian conditions on Odonata (Insecta) assemblages in eastern Amazon basin streams

Riparian vegetation is an important determinant of the physical, chemical, and biological condition of streams, and odonates are useful indicators of riparian condition. To identify environmental factors that structure Odonata assemblages in tropical forest streams, we collected adult odonate specimens and habitat data from 50 stream sites located in the Brazilian municipality of Paragominas (Pará state). We collected 1769 specimens representing 11 families, 41 genera, and 97 species. Of these species, 56 were Zygoptera, and 41 were Anisoptera. Improved environmental condition was reflected in increased Zygoptera species richness and reduced Anisoptera species richness. Channel shading was strongly and positively related to Zygoptera richness, and negatively to Anisoptera richness. Zygoptera species richness, but not Anisoptera species richness, was related positively to bank angle, quantity of wood in the stream bed, electrical conductivity, and decreased water temperature. Altered riparian vegetation structure was the principal determinant of odonate assemblage structure. Our results indicate that maintaining intact riparian vegetation is fundamental for conserving or re-establishing aquatic odonate assemblage structure.

Diversity and population dynamics of Odonata (Insecta: Odonata) in rice growing area of central Gujarat

Odonates diversity was studied in Paddy field of central Gujarat during 2012 to 2015. Total 39 species belonging to 25 genera, under six families and two suborders were recorded. Total 17 species of Zygoptera (damselflies) and 22 species of Anisoptera (dragonflies) were recorded. Community structure and population dynamics of adult odonates were studied at Lingda village during July to December, 2012 through monitoring their population by point count method on three microhabitats (paddy field, village pond and fish farm). Total seventeen species were encounterd in the point count. Diversity index (H’) was highest (2.13) for paddy fields followed by fish farm (2.07) and village pond (1.99). Evenness value of the odonates also ranged between 0.7 and 0.8. Total four species (<em>Viz.</em> Ditch Jewel (25.0%), Green Marsh Hawk (17%), Ruddy Marsh Skimmer and Coromandal Marsh Dart (16% each) were dominant species in all three microhabitats. Both the suborders Anisoptera (dragonfly) and Zygoptera (damselfly) showed similar trend of population fluctuation during the study. Relative abundance was higher and remained constant during 4<sup>th</sup> week of September to 2<sup>nd</sup> week of October.

Are the adult odonate species found in a protected area different from those present in the surrounding zone? A case study from eastern Amazonia

We studied 30 streams in eastern Amazonia, 17 of which were located within a protected area (PA) and the other 13 in the surrounding zone, with the objective of evaluating the diversity of adult Odonata and if there was a difference between the physical habitat variables of the two environments. We hypothesized that a greater diversity of odonate species would be found in the PA due to a greater complexity of habitats. This hypothesis was rejected, however, due to the greater odonate diversity found in the surrounding zone in comparison with the PA. Differences were also found in the species composition of the two environments. Our results indicate that there are differences between the environmental variables in the areas, and the few alterations observed in the surrounding zone may have contributed to the formation of new conditions and habitats appropriate for species that may have been rare. The PA, despite having reduced species richness and abundance in comparison with the surrounding zone, was nevertheless characterized by a more heterogeneous species composition. A quarter of the species were common to both environments, while 34 % were exclusive to the surrounding zone. In this case, it appears that the combination of the protected area and the surrounding zone, which has a low level of disturbance, conserves a wider range of specialist species than either area on its own. The great challenge in the future is finding a way to identify the disturbance levels that would be acceptable, and to prevent over-exploitation of resources in such areas.

“Odonata Community Index – Corsica” (OCIC): A new biological index based on adult odonate populations for assessment of the ecological status of watercourses in Corsica

Corsica is a French island in the western Mediterranean with numerous distinct geomorphological, landscape, and biological characteristics. These specific attributes, mostly related to insularity, are hardly taken into account by the biological indices currently recommended in the framework of the European Union Water Framework Directive “WFD” for assessing the ecological status of watercourses. Thus, this work has focused on developing an innovative biological index adapted to the specific context of territories such as Corsica, based on the Odonata group. In this context, imago sampling of Odonata was performed at 40 representative stations to assess the 33 major permanent rivers of the island. In parallel, various biological, hydrological, and physicochemical parameters affecting the ecological status of these organisms were recorded. The data collected on nearly 30 species of Odonata allowed for the accurate description of the typical populations of Corsican watercourses, highlighting this group's potential as a biological indicator. An indicator value was assigned to the 12 species identified as the most representative of these environments. The results were used to develop 5 biological indices based on simple statistical descriptors. The index that was found to be the best for assessing the ecological status of the watercourses, as indicated by correlation tests, was named “Odonata Community Index – Corsica” (OCIC), and was finally confronted with the 5 biological indices recommended by the WFD and currently used in Corsica. The results of this study confirm the significant potential of the OCIC index compared to other “official” indicators, that are limited in they do not accurately assess all territories. The results of our tests indicate that this new index using Odonata group appears to be a credible method that could potentially improve the evaluation system currently used for monitoring the ecological quality of watercourses in Corsica.

Resident‐immigrant dichotomy matters for classifying wetland site groups and metacommunities

Summary The fact that species have resident (autochthonous) or immigrant (allochthonous) status at any given locality may have strong implications for ecological analysis. We used wetlands and adult odonates as a model system to evaluate the resident‐immigrant dichotomy for two modes of community analysis: (1) grouping sites based on species compositional variation and (2) identifying metacommunity structure. We tested a hypothesis of gradient‐structured (non‐random) resident occurrence versus unstructured (random) immigrant occurrence in the metacommunity context and predicted the resident occurrence would more effectively partition community variation and produce stronger site groupings than total (resident + immigrant) occurrence. Site group classification after fractioning out resident occurrence consistently and in some cases dramatically outperformed total occurrence. Resident damselflies produced the strongest classifications, which we attribute to greater dispersal limitation, environmental sorting or both. As predicted only the resident occurrence led to identifiable metacommunity structures, primarily Clementsian‐style turnover. This suggests the resident occurrence is gradient‐driven with species responding similarly to abiotic filters, whereas immigrant occurrence is more opportunistic and random. The resident‐immigrant dichotomy appears to have strong influence on quantitative classification of sites and metacommunities, and species composition of resident adult damselflies is potentially useful for differentiating and indicating site groups of non‐forested freshwater wetlands.

Community assembly of adult odonates in tropical streams: an ecophysiological hypothesis.

Community assembly theory is founded on the premise that the relative importance of local environmental processes and dispersal shapes the compositional structure of metacommunities. The species sorting model predicts that assemblages are dominated by the environmental filtering of species that are readily able to disperse to suitable sites. We propose an ecophysiological hypothesis (EH) for the mechanism underlying the organization of species-sorting odonate metacommunities based on the interplay of thermoregulation, body size and the degree of sunlight availability in small-to-medium tropical streams. Due to thermoregulatory restrictions, the EH predicts (i) that larger species are disfavored in small streams and (ii) that streams exhibit a nested compositional pattern characterized by species’ size distribution. To test the EH, we evaluate the longitudinal distribution of adult Odonata at 19 sites in 1st- to 6th-order streams in the Tropical Cerrado of Brazil. With increasing channel width, the total abundance and species richness of Anisoptera increased, while the abundance of Zygoptera decreased. The first axis of an ordination analysis of the species abundance data was directly related to channel width. Mean and maximum thorax size are positively correlated to channel width, but no relationship was found for the minimum thorax size, suggesting that there is no lower size constraint on the occurrence of these species. Additionally, a nested compositional pattern related to body size was observed. Our results support the EH and its use as an ecological assembly rule based on abiotic factors. Forest cover functions as a filter to determine which species successfully colonize a given site within a metacommunity. As a consequence, the EH also indicates higher treats for small-bodied zygopterans in relation to the loss of riparian forests in tropical streams.

Bionomic differences in odonates and their influence on the efficiency of indicator species of environmental quality

The influence of environmental changes on organisms depends on their bionomic characteristics, such as mobility, body size, and resource use. Thermoregulatory and dispersal abilities may directly affect the use of odonates as bioindicators since organisms with low dispersal ability can track fine-scale environmental variations and are usually resource specialists. We investigated the utility of dragonflies (Anisoptera) and damselflies (Zygoptera) as bioindicators testing possible relationships to their bionomic characteristics. We assessed the variation in species richness, composition, and indicator values in Cerrado areas by quantitative sampling of adult odonates in streams surrounded by different vegetation types, ordered by the degree of vegetation cover. Species composition was efficient in discriminating impacts affecting riparian vegetation, with low richness of rare and specialist species in impacted areas. Damselflies had more narrow requirements, associated to different shading, depth, and environmental integrity levels. No relation between body-size and species indicator value was observed. Despite this, the main use of those species as indicators, especially the Zygoptera, may be related to environmental disturbance created by changes on vegetation cover suggesting their potential use in the analysis of the environmental quality of riparian areas.

Does the damming of streams in the southern Amazon basin affect dragonfly and damselfly assemblages (Odonata: Insecta)? A preliminary study

Our goal was to investigate whether the loss of riparian forests alters the structure of assemblages and populations of dragonflies and damselflies. We tested the hypothesis that the composition of the odonate assemblages found upstream from dams are significantly different from those found downstream of these barriers. To test the hypothesis, we investigated stream sectors upstream and downstream of three dams located at the extreme of the southern Amazon basin, in the Brazilian state of Mato Grosso. We collected 111 adult odonates, 45 upstream and 69 downstream, representing 18 species, 12 upstream and 10 downstream. The most abundant species was Epipleoneura williamsoni Santos, 1957 (n = 41, 36.9%), followed by Epipleoneura metallica Racenis, 1955 (n = 20, 18%) and Hetaerina curvicauda Garrison, 1990 (n = 17, 15.3%). Statistical ordination separated the different sectors, with the greatest dissimilarity being found between the upstream and downstream I (DS I), and our hypothesis was further supported b...

Ischnura Graellsii(Insecta: Odonata) A Water Pollution Biovulnerability Indicator—Probability Mapping Using Spatial Uncertainty

AbstractMonitoring changes of anthropogenic impacts from a broad scope of species in biodiversity research require practical, easy‐to‐use and efficient assessment as well as monitoring methods. Odonates (Insecta: Odonata) are a valuable tool for assessing freshwater systems' quality and have been used as bioindicators of environmental variety.The Águeda watershed, located in the central west of the Iberian Peninsula, shows an exponential increase in the last 60 years of natural resource exploitation coupled with alterations in consumer habits, causing significant environmental changes and deferred direct effects on the natural habitats.Fourteen river sites, selecteda priori, were sampled. Adult odonates were collected using standardized methods. Selected environmental variables and water quality parameters were evaluatedin situ. Precipitation and altitude were the most important physical, environmental variables in explaining the assemblage structure. Meaningful abiotic–biotic as well as biotic–biotic relationships were set up. Furthermore, situations in the urbanized watershed area showed to be highly impacted and closely related with damselflyIschnura graellsii, which should be targeted as a possible vulnerability indicator for polluted fresh waters.A probability map forIschnura graellsiidistribution was performed using indicator kriging with external drift and spatial uncertainty obtain through the calculation of two categorical maps (binary), corresponding to the mean (0.485) and the trimmed mean by discharging the 10% lower distribution tail (0.533). The subsequent overlapping of both categorical maps (binary) allowed the definition of the higher spatial uncertainty map for surface water contamination. Copyright © 2014 John Wiley & Sons, Ltd.

Analysis of urban impacts on aquatic habitats in the central Amazon basin: Adult odonates as bioindicators of environmental quality

Thirty streams were surveyed in urban and natural settings in the municipality of Manaus in the central Amazon basin (Brazil) with the objective of identifying the species of adult odonates that can be used as bioindicators of environmental quality. The data collected were used to test the hypothesis that species in the suborder Zygoptera are indicators of better-preserved environments due to their smaller body sizes and reduced tolerances to habitat modification, whereas species in the suborder Anisoptera were presumed to be indicators of impacted habitats with no vegetation. The habitats were classified as preserved, intermediate, and degraded, based on their environmental characteristics. A total of 908 specimens were collected, representing 60 species. The results of the indicator value (IndVal) identified 13 species as indicators of environmental quality, of which nine were typical of preserved habitats, two of intermediate habitats, and four of modified habitats (intermediate or degraded). Odonate species richness declined with increasing urbanization, a pattern also presented by the zygopterans, although anisopteran species richness was higher in intermediate habitats. Zygopteran species showed high fidelity/specificity for preserved habitats, although a small number of the species of this suborder showed a similar relationship with intermediate or degraded habitats, whereas anisopterans were associated only with disturbed habitats (intermediate and degraded). Overall, the results indicate that the diagnosis of the adult odonate community can provide a rapid and effective tool for evaluation of environmental quality. As many species are stenotopic, they can be used as indicators of good habitat quality, whereas some of the more eurytopic species can indicate disturbed habitats.