129 research outputs found
Species and life stages of Odonata nymphs sampled with large drift nets in two Wisconsin rivers
Because relatively few nymphs of Odonata are caught in most drift studies, they have been inconsistently reported and little is known about the species and life stages that are predisposed to drift. We used large drift nets with relatively coarse mesh sizes (1500 µm) to sample late-instar odonate nymphs in two large rivers in Wisconsin. These nets were presumed to have advantages over smaller, conventional aquatic insect drift nets, including the capability to sample greater water volumes more quickly, sampling for longer periods of time before nets become clogged with debris, and a reduced likelihood of large, active insects escaping from the nets. Nymphs of 14 species of Odonata in five families were caught, but drift densities were low (0.042 m-3 overall; -3 for most species) and final instar nymphs (F-0) were collected less frequently than younger nymphs (F-1 through FOphiogomphus comprised 78% of the total in the St. Croix River. Ophiogomphus howei Bromley was the most commonly sampled species (drift density of 0.026 m-3), with at least five instars collected
Gynandromorphs in the genera Ophiogomphus Selys, 1854 and Ischnura Charpentier, 1840 (Odonata: Gomphidae,Coenagrionidae)
A gynandromorph of Ophiogomphus smithi Tennessen and Vogt from Wisconsin and a gynandromorph of Ischnura hastata (Say) from Alabama are described. The specimens appear to be bilateral in that they display mostly left/right separation of male and female characters
Gomphus Fraternus (Odonata: Gomphidae) A New Missouri State Record
A male Gomphus fraternus (Say) (Odonata: Gomphidae) was vouchered from the Meramec River at Castlewood State Park, St. Louis, County, Missouri on 7 June 2005. The collection of this specimen is a new state record for Missouri and represents a significant range extension south and westward for this species
Phaenandrogomphus safei, a new species from Sabah, northern Borneo (Odonata: Anisoptera: Gomphidae).
Phaenandrogomphus safei is described from a male from the Kalabakan Forest Reserve, Sabah, Malaysian Borneo. It is the first species of Phaenandrogomphus to be recorded from Borneo. Onychogomphus treadawayi, known from Busuanga Island in the Palawan region of the Philippines, is transferred to Phaenandrogomphus. During this work SHL was funded by
the Natural Environment Research Council (NERC), Proforest (Oxford), the University of Oxford (Varley
Gradwell Travelling Fellowship) and the University of Cambridge (Commonwealth Travel Fund, Tim Whitmore
Fund, Panton Trust).This is the final published version. It first appeared at http://dx.doi.org/10.11646/zootaxa.3905.1.10
New Distribution Records for \u3ci\u3eOphiogomphus Howei\u3c/i\u3e (Odonata: Gomphidae)
New distribution records establish Ophiogomphus howei as a resident species in Wisconsin. Kentucky, Maine, and Minnesota are added as new state records for this seldom-encountered gomphid dragonfly. Larval habitats appear to be undisturbed rivers 10-200 m wide, with sand and gravel sub-strates
Range Extension of \u3ci\u3eStylogomphus Albistylus\u3c/i\u3e (Odonata: Gomphidae) for the Upper Peninsula of Michigan
Larvae, exuviae, and teneral adults of Stylogomphus albistylus (Hagen) were collected from Mountain Stream, within the boundaries of the Huron Mountain Club, in the Upper Peninsula of Michigan (Marquette County). This represents the first published report of this species from the Upper Peninsula of Michigan, and only the second recorded site for the state of Michigan
Form-function relationships in dragonfly mandibles under an evolutionary perspective
© 2017 The Author(s). Functional requirements may constrain phenotypic diversification or foster it. For insect mouthparts, the quantification of the relationship between shape and function in an evolutionary framework remained largely unexplored. Here, the question of a functional influence on phenotypic diversification for dragonfly mandibles is assessed with a large-scale biomechanical analysis covering nearly all anisopteran families, using finite element analysis in combination with geometric morphometrics. A constraining effect of phylogeny could be found for shape, the mandibular mechanical advantage (MA), and certain mechanical joint parameters, while stresses and strains, the majority of joint parameters and size are influenced by shared ancestry. Furthermore, joint mechanics are correlated with neither strain nor mandibular MA and size effects have virtually play no role for shape or mechanical variation. The presence of mandibular strengthening ridges shows no phylogenetic signal except for one ridge peculiar to Libelluloidea, and ridge presence is also not correlated with each other. The results suggest that functional traits are more variable at this taxonomic level and that they are not influenced by shared ancestry. At the same time, the results contradict the widespread idea that mandibular morphology mainly reflects functional demands at least at this taxonomic level. The varying functional factors rather lead to the same mandibular performance as expressed by the MA, which suggests a many-to-one mapping of the investigated parameters onto the same narrow mandibular performance space
Odonata from the Tibesti Mountains and the Ounianga Lakes in Chad, with notes on Hemianax ephippiger accumulating in the desert
Fourteen species of Odonata were collected in Ounianga and Tibesti (Chad, Africa) in March 2014. Among them, only one zygopteran (Ischnura saharensis, with a Saharan distribution), one gomphid (the eremian Paragomphus sinaiticus), and two aeshnids (Anax imperator and Hem ianax ephippiger) were present. The latter species was not only the most common dragonfly, but also the most abundant insect seen in the desert. It is likely that it was in a phase of accumulating individuals, possibly as a prelude to another massive trans-Sahara and even trans-Mediterranean migration, for which the species is well-known. The 10 libellulids recorded were almost all Afrotropical species, but several expand to the Maghreb and even Mediterranean Europe. Only Orthetrum cf. hintzi is a tropical African species that had never been recorded from the desert before
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