| 1. |
- Dalzochio, Marina Schmidt, et al.
(författare)
-
Description of the final stadium larva of Erythrodiplax media (Odonata: Libellulidae) with preliminary key to known South American larvae in the genus
- 2018
-
Ingår i: International Journal of Odonatology. - Abingdon : Taylor & Francis Group. - 1388-7890 .- 2159-6719. ; 21:2, s. 93-104
-
Tidskriftsartikel (refereegranskat)abstract
- The larva of Erythrodiplax media is described and illustrated based on two exuviae of reared larvae and one final stadium larva collected in Xangri-lá, State of Rio Grande do Sul, Brazil. The larva of E. media can be distinguished from other species of Erythrodiplax by the presence of lateral spines on S8 and S9, the number of premental setae (n = 22), palpal setae (n = 7) and by the mandibular formula. We also provide a preliminary key to known South American larvae in the genus. © 2018 Worldwide Dragonfly Association.
|
|
| 2. |
- Hedlund, Johanna, et al.
(författare)
-
New records of the Paleotropical migrant Hemianax ephippiger in the Caribbean and a review of its status in the Neotropics
- 2020
-
Ingår i: International Journal of Odonatology. - : Worldwide Dragonfly Association. - 1388-7890 .- 2159-6719. ; 23:4, s. 315-325
-
Tidskriftsartikel (refereegranskat)abstract
- Tropical America is currently experiencing the establishment of a new apex insect predator, the Paleotropical dragonfly Hemianax ephippiger (Odonata: Aeshnidae). H. ephippiger is migratory and is suggested to have colonised the eastern Neotropics by chance Trans-Atlantic displacement. We report the discovery of H. ephippiger at three new locations in the Caribbean, the islands of Bonaire, Isla de Coche (Venezuela), and Martinique, and we review its reported distribution across the Neotropics. We discuss the establishment of H. ephippiger as a new apex insect predator in the Americas, both in terms of ecological implications and the possible provision of ecosystem services. We also provide an additional new species record for Bonaire, Pantala hymenaea (Odonata: Libellulidae).
|
|
| 3. |
- Hedström, Ingemar, et al.
(författare)
-
An extended description of the larva of Megaloprepus caerulatus from Costa Rica (Odonata: Pseudostigmatidae)
- 2003
-
Ingår i: International Journal of Odonatology. - Abingdon : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 6:1, s. 23-31
-
Tidskriftsartikel (refereegranskat)abstract
- The larva of Megaloprepus caerulatus is described and illustrated from specimens collected near the northern border of Barbilla National Park on the Costa Rican Caribbean slope. Habits and characters of larvae of three different size classes obtained from artificial tree holes permit the identification of small (body length 4 mm, excluding the caudal lamellae) larvae up to the final stadium. New diagnostic characters include the shape of the prementum and head. © 2003 Taylor & Francis Group, LLC.
|
|
| 4. |
- Hedström, Ingemar, et al.
(författare)
-
The dry season governs the reproduction of three pseudostigmatid zygopterans in Costa Rica : (Odonata Pseudostigmatidae)
- 2007
-
Ingår i: International Journal of Odonatology. - Abingdon : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 10:1, s. 53-63
-
Tidskriftsartikel (refereegranskat)abstract
- The large Neotropical zygopterans Megaloprepus caerulatus, Mecistogaster linearis and M. ornata (Pesudostigmatidae) were surveyed during five years, and striking differences in their reproduction patterns were shown: (1) At two study sites in seasonal, tropical semi-dry forests in Pacific Costa Rica, adult M. ornata could be observed throughout the year, occasionally during the dry season up to 24 indivi duals at one time. Larvae were found from the middle to the end of the wet season suggesting a generation time of one year. (2) At two other study sites in aseasonal tropical wet forest in Caribbean Costa Rica, adults of M. caerulatus were observed year round, often in rather low numbers. Larvae of this species as well as M. linearis appeared throughout the year. While dry periods and rainfall certainly are key factors in governing the reproductive patterns of these species in relation to the climatic regimes of their preferred life zones, it is also concluded that competition from other container dwellers, including tadpoles of poison arrow frogs, may be additional factors in explaining their seasonal variation. It is also argued that all three species seem to have a high plasticity in their life cycles and hence are able to adapt to local conditions rather than displaying the same behaviour throughout their range.
|
|
| 5. |
- Koch, Kamilla, et al.
(författare)
-
Morphological differences in the ovary of Libellulidae (Odonata)
- 2009
-
Ingår i: International Journal of Odonatology. - Oxford : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 12:1, s. 147-156
-
Tidskriftsartikel (refereegranskat)abstract
- All female Odonata have been assumed to produce oocytes continuously during their mature life span. However, a recent study of ovariole orientation and development led to the suggestion that Libellulidae are divided into two groups of species, one with continuous, the other with stepwise oocyte production. To find more evidence of this division, we compared the size variation and growth within the vitellarium of the ovary, studying oocytes, and follicle cells. We found that morphological characters discriminate between the two ovary types in eight of the 10 investigated species. In both types we found an increase in all measurements from the anterior to the posterior end of the vitellarium. The increase in oocyte width and follicle cell length was significantly higher in species with a continuous oocyte production. We also noted that follicle cells may have more than one nucleus and that their number can vary during vitellogenesis. Our study confirmed the hypotheses that two different ovary types exist in Libellulidae. The two species not fitting into this grouping could be an artefact of small samp le size due to intraspecific phenotypic plasticity, or else there might be more than two ovary groups, or even a continuum. We could not offer an explanation as to how the process of stepwise oocyte production differs from continuous based production on morphological characters.
|
|
| 6. |
- Koch, Kamilla, et al.
(författare)
-
Morphology of follicle cells of Libellulidae (Odonata)
- 2011
-
Ingår i: International journal of odonatology. - Leiden : Backhuys. - 1388-7890 .- 2159-6719. ; 14:3, s. 257-267
-
Tidskriftsartikel (refereegranskat)abstract
- In libellulids, mature oocyte size varies within and between individual ovaries. The regulating mechanism is not yet understood. Variations in the contents of the follicle cells, and thereby their ability to secrete material into the oocyte, might explain some of the observed differences in oocyte size. We therefore investigated the follicle cell surface, the interstitial space width between follicle cells and between follicle cells and oocytes, the number of nuclei, and the cell compartment proportions using scanning and transmission electron microscopy. In all investigated species, the follicle cells were covered by a basal lamina. We found cytoplasmic microvilli and septate junctions. As we could not find any pores or other structures on the cell surface, endocytosis seems to be the only mechanism transporting material into the follicle cells. Larger follicle cells had larger interstitial gaps between follicle cells and oocytes, larger nuclei and a larger mitochondrial area. Larger interstitial spaces between follicle cells and oocytes may afford more room that can be filled with material from the follicle cell layer. More mitochondria could provide more energy/ATP needed for the transport of the material. The quantity of free ribosomes and the mean number of nuclei seemed to be even more important to the productivity of the follicle cell. All these variations in cell contents cause productivity differences among follicle cells and may explain some of the size differences between oocytes within individual ovaries in libellulids.
|
|
| 7. |
- Nakata, Toshiyuki, et al.
(författare)
-
Recent progress on the flight of dragonflies and damselflies
- 2020
-
Ingår i: International Journal of Odonatology. - : Worldwide Dragonfly Association. - 1388-7890 .- 2159-6719. ; 23:1, s. 41-49
-
Tidskriftsartikel (refereegranskat)abstract
- Remarkable flight performance is key to the survival of adult Odonata. They integrate varied three-dimensional architectures and kinematics of the wings, unsteady aerodynamics, and sensory feedback control in order to achieve agile flight. Therefore, a diverse range of approaches are necessary to understand their flight strategy comprehensively. Recently, new data have been presented in several key areas in Odonata such as measurement of surface topographies, computational fluid dynamic analyses, quantitative flow visualisation using particle image velocimetry, and optical tracking of free flight trajectories in laboratory environments. In this paper, we briefly review those findings alongside more recent studies that have advanced our understanding of the flight mechanics of Odonata still further.
|
|
| 8. |
- Norling, Ulf
(författare)
-
Constant and shifting photoperiods as seasonal cues during larval development of the univoltine damselfly Lestes sponsa (Odonata : Lestidae)
- 2018
-
Ingår i: INTERNATIONAL JOURNAL OF ODONATOLOGY. - : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 21:2, s. 129-150
-
Tidskriftsartikel (refereegranskat)abstract
- Larvae were reared at 21.5 degrees C from eggs from southernmost Sweden, and fed ad libitum to emergence in four different photoperiodic treatments, intended to represent increasing levels of time stress: constant LD 16:8, corresponding to late April (or August) conditions, a shift after about two weeks from LD 16:8 to 19.5:4.5, coarsely simulating late spring, constant LD 19.5:4.5, corresponding to the summer solstice, and a shift from LD 19.5:4.5 to 16:8, coarsely simulating late summer. Mean larval development time significantly decreased in this series: 47.5, 45.2, 43.0 and 39 days (n=11-13 larvae), respectively. This suggests an ecologically relevant integration of absolute photoperiods and changes in photoperiod, allowing larvae to distinguish if LD 16:8 represented spring or late summer, depending on earlier experience. Thus, rapid development, a long day response during spring conditions, is further speeded up by shorter days during late summer. In early stadia, moulting intervals were uniform, but long days may to some extent have programmed young larvae to develop with fewer moults, thereby increasing development rate. In the last four stadia the principal effect was variation in moulting intervals. Adult size was little affected. Homogeneous conditions and low genetic diversity produced a remarkably synchronous development within treatments, with an emergence span of 5-10 days. Due to low numbers of larvae, derived from a single female, and problems with a switch, the generality of these results would need confirmation.
|
|
| 9. |
- Outomuro, David, et al.
(författare)
-
A preliminary study on female-limited colour polymorphism in Lestes sponsa
- 2014
-
Ingår i: INT J ODONATOL. - : Worldwide Dragonfly Association. - 1388-7890. ; 17:2-3, s. 89-93
-
Tidskriftsartikel (refereegranskat)abstract
- Female-limited colour polymorphisms are widespread in Odonata, usually showing an androchrome and one or more gynochromes. Androchromes have been hypothesized to function as male mimics with a consequent decrease of male harassment, although males may also learn to recognize the different female colour morphs. In the Eurasian damselfly Lestes sponsa, the occurrence of two female colour morphs (androchrome and gynochrome) has been known since the beginning of the twentieth century, although this has been generally overlooked. In this work, we studied a Swedish population of L. sponsa by counting the number of females of each morph during nine consecutive days, as well as the number of tandems. Androchromes showed blue pruinescence at similar body parts as males, although more limited at the tip of the abdomen. Moreover, androchromes also showed bright blue coloured eyes as males. We found no indication that androchromes might be a result of age changes in female coloration. The androchrome morph accounted for 19% of the female population. Androchromes did not form tandems at a lower frequency than expected in the population, given the frequency of presence of each morph. Therefore our results suggest that either androchromes in this species do not function as male mimics, or that the population has reached equilibrium with equal fitness for each morph. Other aspects of male harassment and learned mate-recognition, as well as female morph behaviour, would shed light on the evolutionary and ecological significance of female morphs in this species.
|
|
| 10. |
- Renner, Samuel, et al.
(författare)
-
Effects of exotic tree plantations on the richness of dragonflies (Odonata) in Atlantic Forest, Rio Grande do Sul, Brazil
- 2016
-
Ingår i: International Journal of Odonatology. - Abingdon : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 19:4, s. 207-219
-
Tidskriftsartikel (refereegranskat)abstract
- One of the forest types occurring in Southern Brazil is the mixed ombrophilous forest (MOF), a subtype of the Atlantic Forest, which is one of the richest biomes on Earth. This biome currently remains as a highly fragmented mosaic, under pressure from human development. The diversity and ecology of most animal groups in this biome are poorly known. We studied Odonata in a large forest fragment, including an ecological reserve: the Floresta Nacional de São Francisco de Paula (FLONA-SFP), in Rio Grande do Sul, administrated by the Brazilian government. The reserve is dominated by MOF with sectors of Pinus elliottii and Araucaria angustifolia. Three surveys of these forest sectors over one year yielded 42 species, with the highest species richness recorded in the P. elliottii sector. The odonate species recorded here are all generalist in terms of habitat preferences, but they appeared only in low numbers and were very particular in their occurrence pattern. We therefore assume that the introduction of an alien element in the Atlantic Forest has given rise to a new species assemblage, where the ecology of the species is adapted to the novel habitat of Pinus plantations. As expected, the species occurring in the MOF sectors were mainly habitat specialists. The Araucaria plantations had an intermediate species composition. Despite the differences observed in habitat preference between generalist and specialist species, such exotic plantation habitats may act as a temporary biodiversity reservoir for further habitat colonization. © 2016 Worldwide Dragonfly Association
|
|
