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1.
Jugubracon gen. n (type species: Jugubracon ferrugineus sp.n.) from New Guinea is described and illustrated. Jugubracon is related to Bracon , from which it is distinguished by a mid-longitudinally carinate 1st metasomal tergite and a curved fore-wing vein 1-SR+M. Kimavu gen.n. (type species: Kimavu fulvus sp.n.) from Sierra Leone, South Africa and Madagascar is described and illustrated. Kimavu is related to Cratocnema Szépligeti, from which it is distinguished by having long antennae which, in females, have a pale coloured annulus. Brucon annulicornis Brues, 1924, is transferred to Kimavu. Mollibracon gen.n. (type species: Bracon bimaris Turner, 1918) from Australia is described and illustrated. Mollibracon is related to Myosoma Brullé, from which it is distinguished by a strongly curved fore-wing vein 1-SR+M.  相似文献   

2.
In natural communities, closely related species are phenotypically similar but usually spatially and/or temporally isolated. In odonates, interspecific competition occurs not only at the larval or adult stage but also during emergence. We investigated the emergence of two sympatric Anax species, focusing on the temporal pattern, vertical stratification, and body size trend over time. Anax imperator started to emerge two weeks earlier than A. parthenope but most of the emergence season overlapped. Both species showed an asynchronous emergence and the median emergence date was 10.3 days earlier in A. imperator. Sex ratio at emergence was not significantly different from 1:1. Body size of both species increased significantly over time, which contrasts many previous studies. The height of exuvia fixation was not significantly different between species but the larger species A. parthenope selected longer supports.  相似文献   

3.
Larvae of the large dragonfly Hemianax papuensis used four disparate, prey-specific predatory behaviours. Arthropod prey moving on a substratum were stalked and then attacked from a distance. Arthropod prey moving in the water column or at the water surface were approached using 'jet' propulsion and then attacked from a distance. Snails, an unusual prey for an arthropod, were stalked; then the larva manoeuvred about them until a specific orientation was achieved before an attack was made from close range. Dead snails were scavenged, using tactics very similar to those used with live snails, but non-snail carrion was rarely taken. There was no evidence that the possession, by H. papuensis , of specialized behaviours for an atypical prey-snails-lowered its success when attacking other types of 'typical' prey.  相似文献   

4.
Abstract A cladistic analysis of the world Aeshnidae is presented, based on fifty-eight characters of adult and larval anatomy. The ingroup taxa include all the extant genera of Aeshnidae, and the austropetaliid genera Phyllopetalia and Hypopetalia were chosen as the outgroup. The strict consensus tree obtained after successive weighting shows that the subgroups defined traditionally for Aeshnidae are paraphyletic or polyphyletic. The previous reclassification derived from analyses based on wing venation is supported in terms of the monophyly of Aeshnidae, Gomphaeschninae and its sister group comprising the remaining Aeshnidae. Gomphaeschninae is confirmed as sister group of the remaining Aeshnidae (= Aeshnodea Bechly). The sister-group relationships between Gomphaeschna + Sarasaeschna and Linaeschna + Oligoaeschna are corroborated. Within Aeshnodea, three monophyletic groups emerged: Boyeria + ( Petaliaeschna + ( Limnetron + Gynacanthaeschna + Periaeschna )) + (( Cephalaeschna + Caliaeschna ) + ( Allopetalia ( Notoaeschna + Spinaeschna ))); Dendroaeschna + ( Epiaeschna + ( Aeschnophlebia + ( Nasiaeschna + ( Tetracanthagyna + Brachytron )))); and Polycanthagyna + ( Basiaeschna + ( Amphiaeschna + ( Indaeschna + ( Oplonaeschna + ( Racenaeschna + Plattycantha + Agyrtacantha + Triacanthagyna + ( Subaeschna + Austrogynacantha + Gynacantha ) + ( Heliaeschna + ( Neuraeschna + Staurophlebia ))) + (( Castoraeschna + Coryphaeschna + Remartinia ) + ( Oreaeschna + ( Aeshna + ( Anaciaeschna + ((' A .' isosceles + Andaeshna ) + ( Anax + Hemianax )))))). Additional informative characters are required to test the relationships suggested here between the main groups of Aeshnodea and some enigmatic basal taxa ( Antipodophlebia , Austroaeschna , Acanthaeschna , Telephlebia , Austrophlebia and Planaeschna ).  相似文献   

5.
Five remarkable new Afrotropical species belonging to four Old World genera never recorded before for the Afrotropical region (Neophryxe, Calliethilla, Metadrinomyia, Pseudalsomyia) are described and compared with congeners. Existing keys to tropical African tachinid genera are implemented. A brief discussion on the apomorphic support to each genus is provided.  相似文献   

6.
Flight has conferred an extraordinary advantage to some groups of animals. Wing shape is directly related to flight performance and evolves in response to multiple selective pressures. In some species, wings have ornaments such as pigmented patches that are sexually selected. Since organisms with pigmented wings need to display the ornament while flying in an optimal way, we might expect a correlative evolution between the wing ornament and wing shape. We examined males from 36 taxa of calopterygid damselflies that differ in wing pigmentation, which is used in sexual displays. We used geometric morphometrics and phylogenetic comparative approaches to analyse whether wing shape and wing pigmentation show correlated evolution. We found that wing pigmentation is associated with certain wing shapes that probably increase the quality of the signal: wings being broader where the pigmentation is located. Our results also showed correlated evolution between wing pigmentation and wing shape in hind wings, but not in front wings, probably because hind wings are more involved in signalling than front wings. The results imply that the evolution of diversity in wing pigmentations and behavioural sexual displays might be an important driver of speciation due to important pre-copulatory selective pressures.  相似文献   

7.
福建头蜓属一新种(蜻蜓目:蜓科)   总被引:1,自引:0,他引:1  
记述采自福建省邵武市的头蜓属1新种,邵武头蜓Cephalaeschnashaowuensis,sp.nov.。模式标本存放在漳州教育学院。  相似文献   

8.
9.
The genus Calocedrus Kurz is characterized by flattened branches covered with decussate and dimorphic leaves. In this study, we describe fossil foliage of Calocedrus discovered in the Shangcun Formation (early Oligocene) of the Maoming Basin, South China. The fossils have wedge‐shaped branchlet segments and scale‐like strongly dimorphic leaves, similar to the fossil species Calocedrus lantenoisi (Laurent) Tao. There have been no detailed studies of the morphological features and cuticle structures of C. lantenoisi. Therefore, a newly emended diagnosis of the species C. lantenoisi is given based on a detailed study of leaf morphology and cuticular characters exhibited by the Maoming fossils. This is one of the earliest fossil records of Calocedrus in the world, providing additional evidence for the early biogeographic history of this genus and supporting the inference that eastern Asian Calocedrus is primitive among all the living species. The extant species of Calocedrus are mainly distributed in mountainous regions. On the basis of the “nearest living relative” analysis, we propose that the Maoming Basin was adjacent to a mountainous region during the early Oligocene.  相似文献   

10.
Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia. Palms (Arecaceae) are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing. In this study, we describe well-preserved fossil palm leaves from the Oligocene Dong Ho Formation of Hoanh Bo Basin, northern Vietnam. Characters of the fossil leaves, such as a fan-shaped costapalmate lamina, an unarmed petiole, a costa slightly enlarged at the base that then tapers distally into the blade, and well-preserved amphistomatic leaves with cuticles, suggest that they represent a new fossil species, which we herein designate Sabalites colaniae A. Song, T. Su, T. V. Do et Z.K. Zhou sp. nov. Together with other paleontological and palaeoclimatic evidence, we conclude that a warm climate prevailed in northern Vietnam and nearby areas during the Oligocene.  相似文献   

11.
ABSTRACT. Three new species of fossil Anisoptera (dragonflies) are reported from Tiffanian (Late Palaeocene) sediments of the Paskapoo Formation, near Red Deer, Alberta, Canada. The three species are all assigned to the new genus Alloaeschna , which is classified in the subfamily Gomphaeschninae.
Phylogenetic analysis of gomphaeschnine wing venation suggests that the subfamily is paraphyletic, with derived gomphaeschnines such as Boyeria and Linaeschna more closely related to the Brachytroninae and Aeshninae than are other gomphaeschnines. One of the most primitive gomphaeschnines, and the oldest fossil form, is the Jurassic Morbaeschna. Parallelism, convergence and reversal in the evolution of features of the wing venation is common.
The new genus Alloaeschna is at about the same evolutionary grade as the old-world genus Oligoaeschna and the new-world genus Gomphaeschna , and is one of the more primitive known members of the Gomphaeschninae. The new species are the first recorded Palaeocene gomphaeschnines and the oldest known gomphaeschnines from the Americas.
Several extant genera have fossil representatives on continents different from those on which they now survive, suggesting repeated crossing of land bridges and/or widespread ancestral species prior to the separation of the continents, and subsequent extinction leading to present relict distributions.  相似文献   

12.
A three-year investigation was carried out on the life cycle of Aeshna cyanea (Müller, 1764) (Odonata, Aeshnidae) in temporary freshwater pools in Central Italy. The instars were discriminated by size and scatter plot, based on measurements of labium length, head width, metafemur length, forewing-pad length and total larval body length. The prolarvae instar was derived by Dyar's law. The mean increase value index between following and previous instar was between 1.26 and 1.33 for isometric variables, and around 1.96 for the wing-pad allometric variable. A. cyanea entered diapause mainly at the F-2 instar, placing it almost intermediate between the Southern Spain populations, which usually overwintered in the F-3 instar, and those of England and Central Europe, who spent their last winter in F-1. A. cyanea appeared to be a `summer species', as defined by Corbet (1962), and the population we studied had a semivoltine life cycle.  相似文献   

13.
《Palaeoworld》2020,29(4):752-760
A new fossil occurrence of Ostrya (Betulaceae) is reported based on 14 involucre impressions from the lower Oligocene of Löhe Basin, Yunnan Province, Southwest China. They are characterized by their bladder-like shape with longitudinal veins and perpendicular or branched intercostal veins that form a reticulate venation. The discovery of these fossil involucres represents the earliest unequivocal fossil record of Ostrya in East Asia and the record at the lowest latitude. Its fossil history suggests that the modern distribution pattern of Ostrya might have been established since the early Oligocene, and that this genus has inhabited low altitude areas since then.  相似文献   

14.
We compared the age, movement, and time–activity budgets of male Calopteryx maculata damselflies occupying off-stream tree-fall gaps with those at stream sites within a 10-ha woodland. All males collected at off-stream sites were younger than males collected at stream sites—as indicated by their significantly higher wing transmittance. Thirty-three percent of teneral males marked at off-stream gaps moved to stream sites within 4 days (mean distance = 140 m), while mature males marked at stream sites never left the stream. In contrast to stream site males, off-stream males spent significantly more time capturing prey and never engaged in aggressive interactions with other males. Behavioral differences were not due to variations in the operative body temperature. However, malaise trapping revealed a greater frequency of suitable prey in forest light gaps. Our findings support the idea that teneral male Calopteryx leave their emergence sites along the stream for off-stream light gaps to forage without interference and build the energy reserves necessary to attain and hold streamside territories.  相似文献   

15.
Abstract. We estimated the phylogeny of the order Odonata, based on sequences of the nuclear ribosomal genes 5.8 S, 18S, and ITS1 and 2. An 18S‐only analysis resolved deep relationships well: the order Odonata, as well as suborders Zygoptera and Epiprocta (Anisoptera + Epiophlebia), emerged as monophyletic. Some other deep clades resolved well, but support for more recently diverged clades was generally weak. A second, simultaneous, analysis of the 5.8S and 18S genes with the intergenic spacers ITS1 and 2 resolved some recent branches better, but appeared less reliable for deep clades with, for example, suborder Anisoptera emerging as paraphyletic and Epiophlebia superstes recovered as an Anisopteran, embedded within aeshnoid‐like anisopterans and sister to the cordulegastrids. Most existing family levels in the Anisoptera were confirmed as monophyletic clades in both analyses. However, within the corduliids that form a major monophyletic clade with the Libellulidae, several subclades were recovered, of which at least Macromiidae and Oxygastridae are accepted at the family level. In the Zygoptera, the situation is complex. The lestid‐like family groups (here called Lestomorpha) emerged as sister taxon to all other zygopterans, with Hemiphlebia sister to all other lestomorphs. Platystictidae formed a second monophylum, subordinated to lestomorphs. At the next level, some traditional clades were confirmed, but the tropical families Megapodagrionidae and Amphipterygidae were recovered as strongly polyphyletic, and tended to nest within the clade Caloptera, rendering it polyphyletic. Platycnemididae were also non‐monophyletic, with several representatives of uncertain placement. Coenagrionids were diphyletic. True Platycnemididae and non‐American Protoneurids are closely related, but their relationship to the other zygopterans remains obscure and needs more study. New World protoneurids appeared relatively unrelated to old world + Australian protoneurids. Several recent taxonomic changes at the genus level, based on morphology, were confirmed, but other morphology‐based taxonomies have misclassified taxa considered currently as Megapodagrionidae, Platycnemididae and Amphipterygidae and have underestimated the number of family‐level clades.  相似文献   

16.
17.
Males of the damselfly,Mnais pruinosa costalis, exhibit wing color dimorphism: one form has orange wings, and the other hyaline wings which resemble female wings. The former is usually territorial and the latter uses sneaky mate securing tactics. When orange-winged males failed to establish territory, they became floaters that day. Hyaline-winged males perched around their territories and often, formed in tandem without any apparent courtship behavior when they found females. Their copulation frequency was higher and copulation duration longer than those of territorial males. A few females oviposited without remating. Total oviposition duration of females with which a hyaline-winged male mated was more than 32 min per male on average in a day Females that copulated with hyaline-winged males often remated with orange-winged residents before oviposition. Total duration of oviposition bouts of females after mating with floaters was short (15 min), while that with territorial residents was long (66 min). As a result, total oviposition duration of females with which an orange-winged male mated was about 40 min in a day. The reproductive success of the hyaline-winged males may be similar to that of the orange-winged males.  相似文献   

18.
19.
Gunnar Rehfeldt 《Oecologia》1992,89(4):550-556
Summary Predation by orb-weaving spiders and crab spiders on the damselfly Calopteryx haemorrhoidalis was studied at a small stream in Southern France. One species of orb-weaving spider, Larinioides folium, caught 76% of the damselflies which fell prey to spiders. Displacement experiments on spiders on sections of bank and the positioning of webs in male territories show that the density and distribution of damselflies is not influenced by orbweb density or by the position of webs. Predation rates corresponded to orb-web density, but neither for sex nor for stage was there a relationship with damselfly density. Mean daily predation rates ranged between 0.9% for females and 4.1% for adult males. Predation risk to adult damselflies by orb-weaving spiders was male biased, whereas among tenerals there was no bias. Males were captured more frequently at territories near the water. Captures show a maximum at noon when territorial disputes of adult males were most frequent. After orbwebs were placed within territories predation rate of males was strongly increased. Predation risk to adult females in the direct vicinity of the stream was less than in the bank vegetation where they perch close to orbwebs. The risk of predation by crab spiders, which catch damselflies at their perching sites, was not sex-biased.  相似文献   

20.
Summary. Compilation and analysis of the existing literature together with the results of our research carried out since 2000 makes possible an updated catalogue of the West Indian Odonata. Such a catalogue has not previously been available, and dispersed and multilingual literature did not facilitate odonatological studies. The odonate fauna of the Caribbean is currently composed of 108 valid species, of which 36 (32%) are endemic to one or a few islands. The most species-rich families are Libellulidae and Coenagrionidae, together comprising 65% of the total fauna.  相似文献   

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