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In the last decades, studies on sexual selection in odonates have shown a relationship between mating success and costly sexual ornaments, mainly male characters. Here, we conducted a scientometric analysis to assess the state of art of studies on sexual selection in odonates, especially on the role of male ornamentation (pre-copulatory traits) and sperm competition (post-copulatory traits). We found 51 papers focused on sexual ornamentation and 34 on sperm competition. Only one study simultaneously addressed both pre- and post-copulatory traits, nevertheless without an integrative approach. Results show that calopterygids are extensively studied regarding pre-copulatory traits (i.e., male wing pigmentation), while libellulids are mostly studied in post- copulatory traits (e.g., sperm competition) focused research. These preferences seem to be related to characteristics like presence of ornamentation and territoriality, large body size, variation and complexity of sperm removal structures, respectively. For the post-copulatory traits, sperm removal is frequently addressed, but few other strategies, like the investment in sperm quality and quantity, are investigated. Finally, we demonstrate that it is necessary to conduct studies focused on addressing the relationship between pre- and post- mating sexual traits.

The increasing use of dragonflies and damselflies as models in studies on biodiversity in the last decades has unraveled several features of natural processes and mechanisms for species conservation. Nevertheless, biodiversity is a polysemic concept that resolves multiple dimensions that, together, enroll what we observe as species and lineages diversity. One of these dimensions is Ethodiversity, which may represent the individual diversity of behavioral traits and higher organization levels. Hence, measures of Ethodiversity may be used as indicator tools to measure such dimensions of biodiversity. However, we still lack methods and protocols to measure this diversity. Therefore, here we addressed whether damselfly behaviors may act as indicators of environmental impacts. We collected behavioral data of 120 males in two sites, one in an ecological reserve and another in an impacted habitat. Our results show differences in behavioral syndromes and behavioral integrity when comparing populations in impacted and conserved environments. In conclusion, we hope that these results stimulate future endeavors to create a methodological framework to assess behavioral diversity.

Polymorphism in coenagrionids is widely known, mainly for Ischnura. Here, we present the case of I. capreolus, a Neotropical species of which, until now, little information concerning color polymorphism and ontogenetic color changes was known. We used a marking and recapture method to evidence ontogenetic coloration changes in females. We show that, in addition to the gynochrome morph, I. capreolus females also exhibit at least one additional morph: an androchrome color pattern. Gynochrome females (97.1% of marked females) are green-yellow when young and change to a brownish pattern with age, within a week. Androchrome females (2.9% of marked females) exhibit blue coloration, similarly to males. Our study provides the first evidence of ontogenetic color change in I. capreolus. Furthermore, field observations show that I. capreolus is similar to other Ischnura species regarding sexual harassment behavior.

Polythorid damselflies are Neotropical stream dwellers, whose behavior has rarely been recorded. Here we describe the territorial and courtship behavior of Chalcopteryx scintillans McLachlan, an Amazonian damselfly with shiny copper-colored hind wings. Territorial behavior consists of aerial contests, when males engage in threat displays and mutual pursuits in ascending and rocking flights. During courtship, males hold their coppery hind wings still while hovering with their forewings, showing the hind wings to females, which hover in front of the male in response. After copulation, the male exhibits the courtship flight again by hovering over the oviposition resource (i.e. fallen tree trunk) on the stream. The females oviposit on the trunk while the males guard them by perching near and hovering around them constantly. We also present behavioral notes on reproductive and oviposition behavior, and comments on the differentiation between C. scintillans and C. rutilans (Rambur).

Behavioral data on Neotropical coenagrionids is still scanty, with very few studies on their reproductive behavior. Here we present the first description of the reproductive behavior of A. truncatum in a high density population in the Brazilian Neotropical savanna. The observations were made at a pond in an ecological reserve. Males remain at the water searching for females. Females remain in the surrounding vegetation and only approach the water to mate and oviposit. The mean duration of copulation was 25.6±3.26 minutes. Copulations are concentrated between 12:00 and 14:00 h (71%). Females oviposit in tandem with males, sometimes submerging to oviposit. Oviposition took 43.08±22.17 minutes. Female underwater oviposition seems to disrupt male guarding and females emerge from the water by themselves. Male–male interactions usually consist of chases and “facing off”. This damselfly species is apparently non-territorial, since males did not defend resources and searched for females in the area.

Oviposition site selection is crucial in the life history of odonates since females must find a suitable habitat to enhance larval survival and development. Males perch at these sites to get access to females to mate. Here we studied how different types of vegetation influence site selection of the damselfly Oxyagrion microstigma in a Neotropical savanna pond. We identified and quantified the aquatic plants on the study site and investigated the relationship between plant species density, male site fidelity and female oviposition. The results showed that male density increased with higher densities of the Cyperaceae Eleocharis sp. but with lower densities of the Pontederiaceae, Pontederia parviflora. The number of males was also positively correlated with the number of ovipositing females and the duration of oviposition bouts. The females were found ovipositing on sites with Eleocharis sp., which was used as an oviposition substrate. We suggest that the species composition of aquatic vegetation in the env...