共查询到20条相似文献,搜索用时 15 毫秒
1.
The European earwig, Forficula auricularia L., was surveyed using pitfall traps at 3 sites at the Hanford Reach National Monument in south central Washington State. Pitfall traps were collected weekly from April 2002 through April 2003. The earwig was consistently taken during all months of the year at a disturbed, weedy site along the Columbia River (White Bluffs Ferry site) but was rare or not collected in 2 less-disturbed shrubsteppe habitats. Highest numbers occurred during April–May, when immatures accounted for the majority of the catch; immatures reached the adult stage during mid-July, and the species is univoltine at the site. Possible reasons why earwigs have not colonized the monument’s shrubsteppe habitat include the arid climate with lack of available moisture, especially for breeding purposes, and a lack of burrow sites. La tijereta Europea, Forficula auricularia L., fue estudiada usando trampas de caída en tres sitios del Hanford Reach National Monument en el sur del estado de Washington. Se colectaron los contenidos de las trampas de caída semanalmente desde abril de 2002 hasta abril de 2003. La tijereta apareció constantemente durante todos los meses del año en un sitio perturbado de vegetación herbácea en la orilla del Río Columbia (el lugar del antiguo transbordador White Bluffs) pero su colecta fue escasa o nula en dos hábitats de estepa arbustiva menos perturbados. Los mayores números ocurrieron durante abril y mayo cuando los organismos inmaduros representaron la mayoría de los especímenes capturados; éstos alcanzaron la etapa adulta a mediados de julio y la especie es univoltina en este sitio. Posibles causas de que las tijeretas no hayan colonizado el hábitat de estepa arbustiva del Monumento podrían incluir su clima árido carente de agua disponible, especialmente para la reproducción, y una falta de sitios para madrigueras. 相似文献
3.
Gyrodactylus bullatarudis Turnbull, 1956 is described from Xiphophorus helleri × X. maculatus hybrids. Specimens from this host were morphologically indistinguishable from material of this species from Poecilia reticulata and P. sphenops, although differences in host specificity were noted. Gyrodactylus turnbulli sp. nov., a member of the G. eucaliae species group, is described from Poecilia reticulata. Gyrodactylus turnbulli has frequently been confused with G. bullatarudis, although the two species are only distantly related. They can be distinguished by differences in the structure of the dorsal bar, which is deeply notched in G. bullatarudis, and by the relative length of the ventral bar processes. 相似文献
4.
A total of 181 fishes belonging to 10 species were captured near Richfield, Utah, and examined for parasites. A new species of hemoflagellate, Trypanoplasma atraria sp. n., was observed in 3 species: Utah chub ( Gila atraria [Girard]), redside shiner ( Richardsonius balteatus [Richardson]), and speckled dace ( Rhinichthys osculus [Girard]). Seven other species of fishes examined in the study area were negative for T. atraria sp. n. The salmonid leech, Piscicola salmositica (Meyer), collected in the same area harbored developmental stages of Trypanoplasma , suggesting a possible leech vector for the hemoflagellate. Characteristics of Trypanoplasma atraria sp. n. place it near T. salmositica , but the new species is twice as large. 相似文献
6.
Four species of chondracanthid copepods are reported from grenadier fishes (Macrouridae) taken in the deep waters off Japan. They are Chondracanthus neali Leigh-Sharpe, 1930 from the oral cavity floor of Malacocephalus nippoensis Gilbert et Hubbs; Chondracanthodes deflexus Wilson, 1932 from the gill cover of Coryphaenoides armatus (Hector); Jusheyhoea ryukyuensis sp. nov. from the oral cavity wall of Coelorhynchus anatirostris Jordan et Gilbert, C. gilberti Jordan et Hubbs and C. productus Gilbert et Hubbs; and Chelonichondria okamurai gen. et sp. nov. from the gill cover of Coryphaenoides nasutus Günther. A key to the 42 genera of the Chondracanthidae is provided. 相似文献
7.
An investigation was carried out over a five-year period into the blackfly fauna of one of the most important rivers of the North-Central European lowlands, the Oder, together with its major tributaries (Nysa, Stobrawa, O?awa, Barycz, Bobr, Kroisa, Lausitzer Neisse, Warta, Notec), from its source in the Oder Hills to its mouth in the Baltic Sea. Thirteen species were found. The two dominant indicator species, Simulium (Simulium) reptans (Linnaeus) and Simulium (Schoenbaueria) nigrum (Meigen), develop populations of plague proportions within this catchment area. Blackflies of the subgenus Schoenbaueria Enderlein have not been found in Germany or Poland for more than 70 years. However, since 1997, the species S. (Sch.) nigrum was found in the River Oder in enormous numbers together with S. (S.) reptans, and in the vicinity of their breeding sites in Poland and eastern Germany both species are serious pests of man and grazing animals. Notes are given on the biology, distribution and habitat preferences of S. (Sch.) nigrum. The paper concludes with a comparison of the River Oder with some other Central European rivers in respect of its blackfly fauna, together with data on the phenology of the two indicator species. 相似文献
8.
Northern pike, Esox lucius , stocked in the Yampa River in 1977, invaded the mainstream Green River by 1981 and subsequently increased in range and abundance. The speed of this invasion is indicated by two recaptured pike that moved 78 and 110 km, respectively, downstream in about one year. Pike stomachs (n = 123) were usually empty (54.5%), but some contained fish (43%) and nonfish items (2.4%). Red shiner, Notropis lutrensis , and fathead minnow, Pimephales promelas , predominated among the 12 fish species eaten. Walleye, Stizostedion vitreum , presumably introduced to the Green River drainage in the 1960s, was widely distributed but low in abundance. Most of 61 adult walleye stomachs contained food (60.7%) ; of 6 fish species eaten, channel catfish, lctalurus punctatus , and fathead minnow were most frequently consumed. Northern pike and walleye were captured in habitats occupied by endangered Colorado River fishes, particularly Colorado squawfish, Ptychocheilus lucius . Predation on endangered fishes was not detected, but northern pike and walleye consumed at least three other native fishes. The northern pike may pose a threat to endangered fishes due to its population expansion, piscivory, and resource sharing. Diets of northern pike and walleye species should be further evaluated if their abundance increases. 相似文献
9.
Bulbamphiascus incus sp. nov. is described from muddy sediments, high in organics, from below fish cages in salmon farms in two Scottish Lochs. It is characterized by the ornamentation of the urosome, the presence of an anvil‐shaped semi‐hyaline structure on the basis of the male P2 and by the structure of the exopod of the male P5. A form, here given specific status under the name B. scilloniensis sp. nov., is described from St Martin's Island in the Isles of Scilly and is identical to B. incus except for the ornamentation of the urosome in both sexes which is very similar to that found in B. imus. Newly described features of the male of B. denticulatus confirm that this species can only be distinguished from B. imus by the projection at the outer distal corner of the second segment of the antennule in both sexes. 相似文献
10.
Critical thermal maxima (CTM) and thermal preferenda of the common fishes of the Virgin River were examined. Differences in final temperature preferenda and CTM for species with low thermal lability (speckled dace, spinedace, roundtail chub) correspond well with differences in their distribution and abundance in the river. These species shifted their acute thermal preferences relatively little as acclimation temperature increased. For thermally labile species (woundfin, red shiner, desert sucker, and flannelmouth sucker), the final preferendum is a less precise indicator of probably distribution. The woundfin, an endangered fish, has a high CTM (39.5 C at 25 C acclimation) and a labile species preferendum (slope nearest 1) compared to other species in the system. The introduced red shiner likewise has a high CTM and a labile acute preferendum. In cooler temperatures, its acute preferendum shifts more rapidly than does that of the woundfin. At higher temperatures (above 15 C), the red shiner does not shift its acute preferendum as rapidly as does the woundfin. The red shiner, however, has a higher final preferendum. For thermally labile species, influence of acclimation temperature on mean preferendum, together with CTM, provides a better insight into distributional relationships within the system. 相似文献
12.
Summary O, I and II group flounders showed a regular increase in length and weight between April and September, but did not grow during the winter months. These immature fish showed highest condition factors and calorific values in summer and lowest in winter. III and ? IV group flounders had highest condition factors and calorific values in winter prior to spawning and lowest when they returned to the estuary as spents in April. Males matured towards the end of their third year and females towards the end of their fourth. Gonad development started in October and peak gonad weights were attained in November (males) and February to April (females). Diurnal variations in the numbers of fish were very marked on the Sleek of Tarty where larger numbers were caught at night. Little diurnal variation was noticeable on the Forvie Bank mud flat. Largest numbers of flounders were recorded between May and September when the population was 50–100 times larger than the winter low (January to March). Estimates of the total population size are given, based on observed densities on underwater transects. Seasonal changes in the population of flounders on the intertidal mud flats were influenced by four major migrations: -
(1)A spring immigration (April and May) of immature (except the O group) and spent fish, the spent females being present in significantly greater numbers than males. -
(2)O group flounders entered the estuary in late June early/July, approximately two months later than the immigration of O group plaice. -
(3)A proportion of III and ? IV group flounders left the mud flats in July and tagging data suggested that they left for the sea. -
(4)The winter emigration of all age classes started in October and continued through the winter, leaving a small population composed mainly of O group and maturing fish. Cormorants preyed mainly on I and II group flounders in winter and probably accounted for the low numbers of these age groups at this time. 相似文献
13.
ABSTRACTThe genus Pseudopaludicola includes small-sized anurans, widely distributed throughout South America. Twenty-three out of the 25 species occur in Brazil. Although described more than a century ago, from mid-southern Mato Grosso state, central Brazil, Pseudopaludicola ameghini is poorly known. Here we describe the characteristics of reproductive site, amplexus, egg-laying behaviour, eggs and tadpoles of P. ameghini based on specimens and observations performed in the vicinities of the type locality. Pairs of P. ameghini reproduce in shallow and slow groundwater established on hydromorphic terrains, in open environments amidst the Brazilian Cerrado savanna. Reproductive activity occurred between 17:00 and 21:00 h at two sites studied from December 2013 to April 2014. Amplexus is axillary. Eggs are spherical, with a mean diameter of 5.1 mm (yolk plus jelly envelope). Oviposition occurs in shallow sites at a depth of nearly 2.0 cm. Females deposit their eggs one at a time, directly onto sediment at the bottom of waterbodies or attached to submerged vegetation. The tadpole body is oval in dorsal view and globular/depressed in lateral view; eyes are large and dorsally positioned. Nares are large, round, with a small apophysis on marginal rim, dorsally positioned, near the eyes. The spiracle is short, with posterodorsal opening. The oral disc is anteroventral, emarginated laterally, with one dorsal and two ventral gaps; the tooth row formula is 2(2)/2(1), and the upper jaw sheath is ‘arc’ shaped. Pseudopaludicola ameghini has a unique behaviour of oviposition among members of the genus. The differences in reproductive pattern and larval characteristics of P. mystacalis and P. ameghini reinforce the taxonomic validity of the latter, questioned until recently. 相似文献
16.
There are only four polyclad flatworms currently known from temperate waters of Victoria, Australia, although these turbellarians are common inhabitants of rocky shores. A new stylochid flatworm, Stylochus pygmaeus sp. nov. (Platyhelminthes, Polycladida) or oyster leech is described here from Port Philip Bay, Victoria. This flatworm was observed feeding on three species of barnacles by extending its pharynx over its prey and extruding copious amounts of mucus. Worms also preferred to prey on larger‐sized barnacles regardless of the species. Further observations indicated that these worms deposited eggs at night inside empty barnacle shells. Each eggmass was brooded for several days with the worms only moving off to feed. Each egg capsule contained multiple embryos and after 5 or 6 days, positively photo‐tactic, four‐lobed Götte's larvae emerged. Larvae metamorphosed to juvenile flatworms 1–2 weeks post‐hatching but failed to settle and survive. 相似文献
17.
An unusual new genus and species of coral inhabiting pontoniine shrimp from the Yemen is described and illustrated. The new shrimp is remarkable for its very small size and the unique form of its telson. Three other pontoniine shrimps are also reported from the Yemen for the first time, raising the number of such shrimp species known from southern Arabia to 18. 相似文献
18.
Eleven species of Gyrodactylus were found infecting five species of freshwater fishes collected from Rogate (West Sussex, England). These were G. arcuatus and G. gasterostei from Gasterosteus aculeatus, G. pungitii from Pungitius pungitius, G. aphyae, G. laevis, G. limneus, G. macronychus and G. minimus from Phoxinus phoxinus, G. pavlovskyi and G. sedelnikowi from Noemacheilus barbatulus and G. rogatensis n.sp. from Cottus gobio. G. (Limnonephrotus) rogatensis is a member of the G. wageneri species group, and can be distinguished from closely related species ( G. aphyae, G. pungitii and G. gasterostei) by its relatively long marginal hooks and by the abruptly tapering toes of its marginal hook sickles. Each parasite was collected from a single host species, and each was narrowly site-specific. With the exception of G. rogatensis, all of the gyrodactylids collected at Rogate also occur in Continental Eurasia, suggesting that they colonized Britain with their hosts via the Doggerland land bridge after the Devensian glaciation. This study demonstrates both the potential of Gyrodactylus for studies of parasite-host coevolution, and the need for critical taxonomic analysis of members of the genus. 相似文献
19.
Six species of copepods parasitic on elasmobranch fishes from the Peruvian coast has been recorded. Two of them, Eudactylina peruensis and E. myliobatidos parasitic on Rhinobatos planiceps (Rhinobatidae) and Myliobatis chilensis (Myliobatidae), are considered new species. New geographical and host records for Pseudocharopinus narcinae Pillai, Pseudocharopinoides myliobatidos Castro and Baeza, Perissopus oblongus (Wilson) and Trebius latifurcatus (Wilson) are included, as also is a checklist of copepod species parasitic on elasmobranch fishes from the coast of the South American Pacific. 相似文献
20.
ABSTRACTVideofilms of a foraging flying gurnard ( Dactylopterus volitans) were collected at Itaipu, Niterói, RJ, Brazil. Analysis revealed details of the use of anterior parts of the pectoral fins which act as digging ‘hands’ to access infaunal prey items that are subsequently captured by oral suction feeding. Each pectoral fin has two distinct sections articulated separately on the pectoral girdle. The digging ‘anterior pectoral fin’ mainly consists of segmented and flexible fin rays but has an anterior robust unsegmented ray that provides an edge to the ‘hand’, allowing penetration of the substratum. The huge ‘posterior pectoral fins’ are supported by unsegmented rays. Most digging episodes involved one ‘hand’ and consisted of 1–7 cycles of movement with frequencies 1.15–3.74 cycles s ?1. During a cycle, the ‘hand’ is moved forwards and medially above the substratum, then is twisted medially and simultaneously depressed so that the anterior unsegmented ray impacts and enters the substratum. The hand is then drawn backwards and laterally to disturb the substratum. To prevent upward pitching of the head during digging, the ‘posterior pectoral fins’ are both moved anteriorly and laterally to shift the centre of gravity forwards while the caudal and ?second dorsal fins continue to provide propulsive force. 相似文献
|