bluuebunny/crossref_metadata_2025 huggingface dataset:
Description and first occurrence of Myxidium zealandicum (Protozoa: Myxosporidia) in the North American eel Anguilla rostrata LeSueur
Authors: Komourdjian M. P. , Hulbert W. C. , Fenwick J. C. , Moon T. W.
Published: August 2008

Myxidium zealandicum Hine, 1975 is described from gills and kidney of the North American eel Anguilla rostrata collected from the St. Lawrence River near Quebec City and Cornwall. Cysts of M. zealandicum on gills measured up to 1 by 2 mm and in kidneys up to 15 by 20 mm. In addition to single spherical cysts, several polymorphous forms were also observed on the gills. Polymorphous cysts were not found in the kidney. Different stages of spore development were evident in gill cysts and were differentiated by means of a lead hematoxylin – fast green stain. Number and pattern of spore striations were examined by scanning electron microscopy and were highly variable. The invasion of the parasite into kidney tissue appeared to result in less physiological damage to the host than did gill invasion. The existence of this parasite, previously found in eel species in New Zealand, in a North American eel species is discussed.
Increased vulnerability of amphipods to predation owing to altered behavior induced by larval acanthocephalans
Authors: Bethel William M. , Holmes John C.
Published: August 2008

The amphipods Gammarus lacustris and Hyalella azteca, when infected with the acanthocephalan larvae Polymorphus paradoxus, P. marilis, or Corynosoma constrictum, show altered evasive behavior and (or) responses to light. We propose that the behavioral alterations are manifestations of an evolutionary strategy adopted by the parasites for enhancing transmission to their respective definitive hosts, and that the differences in behavior, and consequent microdistributions of infected amphipods, are tactical and specific to the different feeding habits of the definitive hosts. This hypothesis was tested, in part, by exposing equal numbers of infected and uninfected amphipods to two of the definitive hosts of P. paradoxus: mallard ducks and muskrats. Gammarids infected with cystacanths of P. paradoxus were significantly more vulnerable to predation by mallards and to accidental ingestion by muskrats. Hyalellids harboring cystacanths of C. constrictum, which use several species of waterfowl, including mallards, for definitive hosts, were more vulnerable than uninfected hyalellids, but less vulnerable than gammarids infected with P. paradoxus. No gammarids infected with cystacanths of P. marilis were eaten by mallards or muskrats; P. marilis is not infective to either of these hosts.
The first North American record of Aporrectodea icterica (Savigny, 1826) (Oligochaeta, Lumbricidae), with observations on the colonization of exotic earthworm species in Canada
Authors: Schwert Donald P.
Published: August 2008

The first North American record of the European lumbricid Aporrectodea icterica (Savigny, 1826) is reported. The anatomy and external morphology of the species is described, and its probable mode of introduction is discussed with respect to the colonization of other exotic earthworm species in Canada.
Aggression, testosterone, and the spring decline in populations of the vole Microtus townsendii
Authors: Krebs Charles J. , Halpin Zuleyma Tang , Smith James N. M.
Published: August 2008

Many vole populations decline sharply in size at the start of the spring breeding season. We attempted to test the hypothesis that aggressiveness controls the magnitude of the spring decline in Microtus townsendii by implanting male voles with testosterone pellets in January 1975. The spring decline was very slight on the control grid and nearly absent on the experimental area, the opposite effect to what we predicted. The amount of skin wounding increased at the same rate on both experimental and control areas as voles entered breeding condition. Aggression tests in a neutral arena showed no differences in aggressive behavior scores for testosterone-implanted males compared with control males. In a more carefully controlled laboratory test we were unable to alter aggressive behavior by either of two levels of testosterone injections. We concluded that aggressiveness in Microtus townsendii could not be altered by testosterone treatments on intact males. Our field test of the aggression hypothesis thus failed.
The salivary gland chromosomes of seven species of Prosimulium (Diptera, Simuliidae) in the mixtum (IIIL-1) group
Authors: Rothfels K. H. , Freeman D. M.
Published: August 2008

The paper has two aspects: (1) It describes the salivary gland chromosomes of Prosimulium mixtum, P. saltus, P. approximatum, P. mysticum, and P. rhizophorum of the eastern North American IIIL-1 or mixtum group. The chromosomes of P. fontanum (CIt, IIIL-1) have been described previously. Description of the complement of P. fuscum (IIIL) is included because of the apparent close relationship of that species and P. mixtum. The cytological criteria provided should make possible identification of last-instar larvae of all known species of the IIIL-1 group. (2) The study leads to some inferences regarding evolutionary mechanisms. The centromere region of each of the three chromosomes exists in at least two alternate forms (CIs/CIt, CIIs/CIIi, CIIIs/CIIIi); sex chromosomes may be based on one or the other of the two alternative sequences in CIII, and extra heterochromatin and chromocenters may be present or absent. Contrary to a priori concepts, which visualize restriction of new chromosomal traits to single lineages, virtually all possible combinations of chromosomal traits are observed. This indicates that in this group of black flies long-lived polymorphisms provided the basis for subsequent interspecific chromosomal differentiation.
Ultrastructure of sex pheromone gland cells in Lobesia botrana Den &Schiff. (Lepidoptera: Olethreutidae)
Authors: Lalanne-Cassou B. , Percy Jean , MacDonald J. A.
Published: August 2008

In newly emerged and 48-h-old female adults of Lobesia botrana the sex pheromone gland cells are columnar. Organelles characteristic of lipid-producing cells are very prominent. Smooth tubular endoplasmic reticulum is extensively developed but few lipid droplets are observed. Numerous microbodies are present and are located, along with the Golgi complexes, primarily in the vicinity of the nucleus. The apical plasma membrane is folded. The cuticle overlying the gland cells differs from unmodified cuticle in the number and location of epicuticular filaments. They originate near the bases of the furrows between the apical folds.
Recruitment patterns of coral reef fishes on the fringing reef of Curaçao, Netherlands Antilles
Authors: Luckhurst Brian E. , Luckhurst Kirsten
Published: August 2008

The recruitment patterns of 16 species of coral reef fishes from seven families were investigated. The Gobiidae are represented by five species and the Pomacentridae and Apogonidae by four and three species respectively. Data are presented for the abundance of size-designated postlarval recruits for a 14-month period. These data are from three transects with quadrats at depths of 10, 20, 30, and 40 m. Most of the species show two principal peaks in their abundance patterns, one in the spring (March–May) and one in the fall (September–November). The species with the largest sample sizes had recruits present essentially throughout the year.
Effects of the mermithid nematode Mermis nigrescens on the levels of hemolymph and fecal uric acid in its host, the migratory locust Locusta migratoria
Authors: Condon William J. , Gordon Roger
Published: August 2008

Second- and third-instar nymphs of the migratory locust Locusta migratoria were infected with ova of the mermithid nematode Mermis nigrescens then compared with a group of uninfected (control) insects with respect to hemolymph and fecal uric acid levels. Twenty-four days after infection (i.e. when parasitic development had been completed), the hemolymph of infected hosts contained over five times the concentration of uric acid as that of controls, while the concentration of fecal uric acid was reduced to one-quarter of the control level in parasitized insects. These alterations of blood and fecal uric acid levels owing to mermithid parasitism are discussed with respect to the physiology of the host–parasite relationship.
Histochemical localization of phospholipids in the olfactory epithelium of fish
Authors: Evans Robert E. , Hara Toshiaki J.
Published: August 2008

Histochemical localization of phospholipids in the olfactory epithelium of rainbow trout (Salmo gairdneri), whitefish (Coregonus clupeaformis), Arctic char (Salvelinus alpinus), brook trout (Salvelinus fontinalis), lake trout (Salvelinus namaycush), and black bullhead (Ictalurus melas) was examined. The present results indicate that phospholipids are highly localized in the receptor neurons of all species examined, present not only in the membranes, but also in the cytoplasm. Although the phospholipids of membranes and cytoplasm may not be of the same kind, their localization suggests a role in olfactory function. The Baker acid hematein method shows clear morphological features of the olfactory neurons beyond those obtainable by routine histological methods. The technique may be useful in determining morphological changes and (or) phospholipid alterations caused by a deleterious environment.
Why breed early? A study of reproductive tactics in Peromyscus
Authors: Fairbairn Daphne J.
Published: August 2008

Female deer mice (Peromyscus maniculatus) near Vancouver, British Columbia, were found to have a bimodal pattern of breeding. This paper compares the success of females that attempted to breed in the early peak of breeding with that of females that did not breed until the later breeding peak. While the average success was about the same for the two tactics, early breeding had a much higher variance. It is suggested that this difference in variances would result in eventual elimination of the early-breeding phenotype, unless it were favored by other factors. Differences in the selection pressures on males and females, and the relatively frequent occurrence of years of good reproductive success for early-breeding females, may contribute to the maintenance of this phenotype in the population. A hypothesis is presented to explain both the bimodality of the breeding pattern, and the dominance of the second breeding peak.
Cardenolide content of some leaf- and stem-feeding insects on temperate North American milkweeds (Asclepias spp.)
Authors: Isman M. B. , Duffey S. S. , Scudder G. G. E.
Published: August 2008

The cardenolide content of eight species of insects which feed on the leaves and stems of milk weed (Asclepias spp.) in temperate North America was examined. Cerambycid beetles of the genus Tetraopes contained small quantities of cardenolides. while two genera of chrysomelid beetles, Chrysochus and Labidomera, contained little or no cardenolides in their bodies. All of these insects are thought to be warningly coloured. The cardenolide content of Tetraopes, in contrast with other milkweed herbivores such as the lygaeid bugs Oncopeltus fasciatus and Lygaeus kalmii, appears to be limited by physiological factors, rather than the cardenolide content of the host plant. Cardenolides were not detected in the pupae of an arctiid moth which has an aposematic larva, a cryptic grasshopper, or a cryptic plant hopper, all of which fed on milkweeds known to contain cardenolides. The implication for chemical defense and the position of these insects in mimicry complexes is briefly discussed. It appears that few of the principal milkweed-feeding insects in temperate North America may use host-derived cardenolides as a chemical defense strategy.
Effect of the parasite Wohlfahrtia vigil on Microtus townsendii populations
Authors: Boonstra Rudy
Published: August 2008

This paper gives the first record of W. vigil parasitizing a wild species in Canada. The incidence of parasitism of the vole M. townsendii was at a maximum from August to mid-September. Of 1933 voles observed during this time, 5.4% were parasitized, and all age-classes were equally susceptible. Parasitism by W. vigil appeared to be facilitated by the presence of botflies (Cuterebra spp.). Survival of voles parasitized by W. vigil was severely affected, with only 5% living 2 weeks later.
Onchocerciasis (Nematoda: Filarioidea) in bovine leg joints
Authors: Webster W. A. , Dukes T. W. , Bundza A.
Published: August 2008

Eleven cases of bovine onchoceriasis associated with mineralized subcutaneous nodules in the area of the knee joint are reported from Saskatchewan and Manitoba. The morphology of recovered portions of nematode cuticle is not identical with that of either Onchocerca gutturosa or O. lienalis and the specific identity of these specimens is therefore undertermined.
The effects of hypophysectomy on liver glycogenolytic enzymes and starvation response in goldfish (Carassius auratus L.)
Authors: Walker R. M. , Johansen P. H.
Published: August 2008

The role of the pituitary gland in goldfish liver carbohydrate metabolism was studied by examining the effects of its removal on the livers of starved animals and on glycogenolytic enzymes.Five weeks starvation after hypophysectomy or sham operation resulted in significantly lower total liver glycogen levels compared with respective fed controls. The larger liver glycogen reserves of starved hypophysectomized fish than fed, sham-operated animals indicate gluconeogenesis is operating to produce glycogen.Glucose-6-phosphatase (EC 3.1.3.9) and glycogen phosphorylase (EC 2.4.1.1) were assayed in liver supernatant fractions from hypophysectomized and sham-operated goldfish. Hypophysectomy resulted in an apparent decline in the activity of glucose-6-phosphatase, but no change in glycogen phosphorylase, compared with sham-operated controls. Reduced glucose-6-phosphatase activity is consistent with lowered glycogenolysis as a cause of liver glycogen accumulation in hypophysectomized goldfish. It is suggested that reduced glycogenolysis could be related to reduced peripheral use of carbohydrate. The possible role of ACTH and glucocorticoids is discussed.
Lichen species preference by reindeer
Authors: Holleman D. F. , Luick J. R.
Published: August 2008

The preference by reindeer for five species of lichens commonly found on Central Alaska rangelands was tested under controlled laboratory conditions. Results indicate that reindeer are strongly species selective in their lichen grazing habits. The five tested species ranged as follows in order of decreasing acceptibility: Caldonia alpestris, C. rangiferina, Stereocaulon paschale, Cetraria richardsonii, and Peltigera aphthosa.
Immunodiffusion comparisons of the serum albumins of marine and land iguanas from different islands in the Galapagos Archipelago
Authors: Higgins Paul J.
Published: August 2008

Serum albumin of the Santa Cruz Island Galapagos marine iguana, Amblyrhynchus cristatus, was isolated by ion-exchange chromatography of an acid-precipitable alcohol-soluble fraction of whole serum. Antigenic differences could not be resolved among the albumins of several morphologically diverse marine iguana populations in agar double-diffusion assay using rabbit antiserum to the albumin of A. cristatus of Santa Cruz Island. The antigenic composition of the serum albumins of Iguana and Conolophus were similar, relative to Amblyrhynchus, although Conolophus albumin possessed determinants cross-reactive with marine iguana albumin which were not found in Iguana.
Spectral mechanisms in the retina of the Arctic ground squirrel
Authors: Jacobs Gerald H. , Tootell R. B. H.
Published: August 2008

The electroretinogram (ERG) was used to investigate the spectral mechanisms present in the retina of the Arctic ground squirrel (Spermophilus undulatus). Under conditions of dark adaptation, the spectral sensitivity of this eye is adequately accounted for by the operation of a typical mammalian rhodopsin (500-nm peak) indicating that, like other ground squirrel species, the Arctic ground squirrel eye probably contains a population of functional rods. When the eye was adapted to lights having a luminance of 0.1 cd/m2 or greater, spectral sensitivity shifted to a new peak location of about 520 nm. Experiments involving chromatic adaptation led to the conclusion that there are at least two spectral mechanisms in this retina which are operative at photopic light levels. These results, along with measurements of preretinal absorbance, indicate that the spectral mechanisms in the retina of the Arctic ground squirrel are very similar to those previously described for several other species of ground-dwelling sciurids.
Chromosomal homology of wood bison and plains bison
Authors: Ying K. L. , Peden D. G.
Published: August 2008

Karyotypes of wood bison (Bison bison athabascae) and plains bison (Bison bison bison) were studied. Both subspecies were characterized by the same number of chromosomes (2n = 60), acrocentric autosomes, submetacentric X chromosomes, and an acrocentric Y chromosome. G-banding patterns suggest that when comparing wood bison and plains bison, 20 pair plus the sex chromosomes are homologous. Whether or not the remaining nine pair of chromosomes are homologous remains unknown.
Prey capture by the African lion
Authors: Elliott John P. , Cowan I. McTaggart , Holling C. S.
Published: August 2008

The capture of prey by the African lion in Ngorongoro Crater, Tanzania, is examined. For analytic purposes the process is envisaged as a consecutive set of events: searching, stalking, attacking, and subduing prey.Initiation of prey capture activity by the lion arises from the interaction of degree of stimulation presented by the prey, timing of the activity cycle of the lion (diurnal or nocturnal), and its level of hunger. These factors yield thresholds for initiation which result in kills being directly related to prey density at high and low densities and inversely density dependent at intermediate prey densities.Success in stalking appears to depend primarily upon the failure of the prey to see the approaching lion until it is within its effective distance. Using data from actual stalks and contrived experiments, the probability is calculated of the lion being detected for a range of conditions.The attack involves a matching of the sprinting abilities of the predator and prey. To analyze this aspect in detail, the velocity curves of running are defined for the lion and four prey species.
Digestive processes of haematophagous insects. XIV. Haemolytic activity in the midgut of Glossina morsitans morsitans Westwood (Diptera: Glossinidae)
Authors: Gooding R. H.
Published: August 2008

A haemolytic agent (haemolysin), which lysed rabbit erythrocytes in an isotonic buffer. occurred in the digestive section of the midgut of adult male and female tsetse flies (Glossina morsitans) but not in the anterior, nondigestive section of the midgut. Haemolysin from females also lysed horse, cow, and pig erythrocytes, and it occurred in the midgut lumen but not in the midgut wall 6, 24. and 48 h after feeding. Little or no haemolysin was present in unfed flies but it was present in the midgut by 3 h after feeding on a rabbit: maximum activity occurred in the midgut 24–48 h after feeding. Flies fed on a meal containing 20 μg or more puromycin/ml produced only small quantities of haemolysin. Flies fed upon erythrocytes, haemoglobin, methaemoglobin, and myoglobin produced large quantities of haemolysin while those fed upon erythrocyte stroma, serum proteins, cytochrome c, or 1 mM ATP in 0.85% NaCl did not.
Life history and reproduction of two species of predacious mites, Phytoseiulus persimilis Athias-Henriot and Amblyseius andersoni (Chant) (Acarina: Phytoseiidae)
Authors: Amano Hiroshi , Chant D. A.
Published: August 2008

The basic biological characteristics of two species of predacious phytoseiid mites, Phytoseiulus persimilis and Amblyseius andersoni, were studied in the laboratory. The results showed that P. persimilis had a higher reproductive rate during a shorter oviposition period and produced more progeny than A. andersoni. Amblyseius andersoni is considered to be along-lived phytoseiid and its rate of predation on adult female spider mites was higher than that of P. persimilis. With both species, unmated females did not reproduce and consumed significantly fewer prey than mated females.
The effects of population density and food surface area on body weight of Acheta domesticus (L.) (Orthoptera: Gryllidae)
Authors: Tennis Patricia S. , Koonce Joseph F. , Teraguchi Mitsuo
Published: August 2008

Experiments were performed to determine the effects of population density and food surface area on individual size (wet weight) of the house cricket, Acheta domesticus (L.). Three initial population densities (50, 200, and 400 hoppers per microcosm) were used to study the effects of population density, three food surface areas (one, two, and three petri dishes, 9.0 cm in diameter) were used to assess the effects of food surface area, and each treatment was replicated with three populations. Mortality increased and individual weight (at 53 days) decreased with increasing density. Both percentage survivorship and mean body weight increased with increasing food surface area. In both sets of experiments the mean size of emerging adults (0–24 h) decreased with increasing nymphal development time, and nymphal development time increased with increasing density and decreasing food surface area. On a daily comparison the mean size of emerging adults of both sexes decreased with increasing density, and the mean size of females increased with decreasing food surface area.
Seasonal dynamics of American dog tick, Dermacentor variabilis (Say), populations in southwestern Nova Scotia
Authors: Garvie Maxwell B. , Mckiel John A. , Sonenshine Daniel E. , Campbell Alan
Published: August 2008

Seasonal activity and host relationships of the American dog tick in three areas of southwestern Nova Scotia are described from 1973 to 1975. The majority of Dermacentor variabilis individuals undergo a 2-year life cycle in Nova Scotia. Unfed adults and larvae are the two main overwintering stages. Adult tick activity extends from April to mid-August, with one population peak during May and (or) June. Peak adult densities, based on mark–recapture methods, were estimated between 7887 and 20 909 ticks per hectare at two areas during 1974 and 1975. Larval activity extending from late April to September was usually bimodal. The main peak of overwintered larvae engorged during June, while a second peak of recently hatched larvae, depending on weather conditions, usually occurred during August. The main relative larval density during the dominant spring peak was 3.95 larvae per host. Nymphal populations occurred between May and August with the unimodal activity pattern averaging 3.85 nymphs per host at the peak during June. The voles Microtus pennsylvanicus and Clethrionomys gapperi sustained almost 80% of all larvae and over 85% of all nymphs collected from mammal hosts. The snowshoe hare, Lepus americanus, and the jumping mouse, Zapus hudsonius, also harbored substantial numbers of immature ticks. Dermacentor variabilis life cycles studied in Massachusetts, Virginia, and Nova Scotia are compared.
Radiothyroxine kinetics in yearling brook trout, Salvelinus fontinalis (Mitchill), on different levels of dietary intake
Authors: Higgs David A. , Eales J. G.
Published: August 2008

Groups of yearling brook trout maintained on a 12 h light: 12 h dark photoperiod regime and held between 10.5 and 12.5 °C were either fed once daily 2.5 or 5.0% of their body weight (dry weight of food (grams)/dry weight of fish (grams)) or were starved for 37 days. All fish were then injected into the circulation via the heart with 1.5 μCi (1 Ci = 37 GBq) of 125I-labelled L-thyroxine (*T4; specific activity 37 μCi/μg). Fed fish received their prescribed rations 18 h before and 4, 29, 53, and 77 h after *T4 injection.Starvation lowered the T4 metabolic clearance rate (MCR), plasma T4 level, T4 degradation rate (T4DR), extent of *T4 deiodination, and conversion of *T4 to *T3 (125I-labelled 3,5,3′-triiodo-L-thyronine).Relative to trout on the 2.5% ration, those on the 5.0% ration had a higher fractional turnover of *T4 in plasma, a smaller T4 distribution space, lower MCR, higher plasma T4 levels, greater T4DR, and more extensive conversion of *T4 to *T3.It is concluded that different caloric and (or) nutrient intakes have a pronounced effect on T4 kinetics and conversion of T4 to T3 in brook trout.
Siphonaptera from mammals in Alaska
Authors: Haas Glenn E. , Barrett Richard E. , Wilson Nixon
Published: August 2008

Twenty-three species of fleas were collected from 18 species of wild mammals, 2 domesticated species, and man. Ctenocephalides felis felis (Bouché) and Hystrichopsylla dippiei spinata Holland are new records for the state. Rhadinopsylla alphabetica Jameson &Sakaguti is a new record for North America.
A new species of the genus Notholca Gosse, 1886 (Brachionidae: Rotifera), from Great Slave Lake, N.W.T.
Authors: Chengalath R.
Published: August 2008

A new rotifer species of the genus Notholca Gosse, 1886 from Great Slave Lake, N.W.T., Canada, is illustrated and described.
The resurrection of Filariopsis van Thiel 1926 (Metastrongyloidea: Filaroididae) for filaroidid lungworms from primates
Authors: Webster W. A.
Published: August 2008

Filariopsis van Thiel 1926 is resurrected and redefined to include those species formerly in Filaroides van Beneden 1858 which have been described from primate hosts. Included in Filariopsis are F. asper van Thiel 1926. F. arator Chandler 1931 (= F. cebi Gebauer 1933), F. cebuellae (Liu 1965) n.comb., F. gordius (Travassos 1921) n.comb., and F. barretoi (Travassos 1921) sp.inq. Filariopsis is characterized by possessing, on the male tail, two pairs of large subventral postanal papillae with multiple nerves and indications of being lobed, and up to two pairs of smaller, single, posterior papillae.
Systematics and ecological notes on Ostracoda from container habitats of some South Pacific islands
Authors: Victor Reginald , Fernando C. H.
Published: August 2008

Nine species of Ostracoda are reported from container habitats of some South Pacific islands. Two of these are new to science, four are already known, and three are identified only to the genus due to lack of material. Ecological information has been compiled for the species reported.
Rhabdometra alpinensis n.sp. (Cestoda: Paruterinidae: Dilepididea) from southern white-tailed ptarmigan (Lagopus leucurus altipetens Osgood) in Colorado, U.S.A., with a key to the species of Rhabdometra Cholodkowsky, 1906
Authors: Olsen O. Wilford , Haskins Arthur G. , Braun Clait E.
Published: August 2008

Rhabdometra alpinensis n.sp. is described from white-tailed ptarmigan (Lagopus leucurus altipetens) from Colorado. A key to the known species of Rhabdometra is included. Rhabdometra terricoli Sharma, 1947 is transferred to Anonchotaenia Cohn, 1900. Rhabdometra alpinensis, R. nullicollis, and R. tomica are similar in having the genital pore anterior to the middle of the lateral margin of the proglottid and the testes arranged in one group on each side of the ovary. There are 30–49, 60, and 12–30 testes, respectively. In R. alpinensis, the cirrus pouch is nearly equal in diameter throughout its length, whereas in the other two species, it is narrow distally and broad proximally.
Aspects of the metabolism of 10-hydroxy-2-decenoic acid, the natural lipid of honeybee (Apis mellifera L.) larval diet
Authors: Dixon S. E. , Shuel R. W.
Published: August 2008

The fatty acid unique to the natural diet of honeybee larvae, 10-hydroxy-2-decenoic acid (10-HDA) is not metabolized by the mitochondria but by the microsomal fraction of larval homogenates. The only other fatty acid metabolized was γ-hydroxybutyrate and this by the mitochondria. The rate of 10-HDA oxidation was enhanced by ferrous ion and NADPH.
The fishes and the aquatic environment of the central Amazon basin, with particular reference to respiratory patterns
Authors: Kramer D. L. , Lindsey C. C. , Moodie G. E. E. , Stevens E. D.
Published: August 2008

This paper surveys the biology of central Amazonian fishes and the physicochemical conditions of their habitats, with particular emphasis on factors related to respiration, in order to place in an ecological perspective the studies of respiratory physiology carried out on the 1976 Alpha Helix Amazon Expedition.The environment is strongly influenced by the annual flood cycle and is characterized by high temperatures and widespread hypoxia. Important differences exist among habitats in the absolute levels and degree of dairy and seasonal variation in temperature and oxygen supply.Air-breathing fishes are numerous and diverse in comparison with other types of aquatic environment, but make up only a small proportion of the total fauna, even in the more hypoxic habitats. Many other species use the oxygenated surface layers for branchial respiration. The potential interrelationships between respiratory strategies and other aspects of the species biology such as feeding niche, habitat type, aniipredator strategies, and capability of overland movement s are discussed.
The occurrence and possible significance of chloridelike cells in the nephron of Amazon fishes
Authors: Hulbert W. C. , Moon T. W. , Bailey J. , Hochachka P. W.
Published: August 2008

The cell composition, ultrastructure, and ion-activated ATPase content of the kidneys in two Amazon erythrinid fishes were compared. In both, three main segments are readily recognized in the nephron. The first-segment cells contained an extensive brush border, ample lysosomes, large and abundant mitochondria with electron-dense matrices, and extensive tubular systems. The second-segment cells were readily recognized by the occurrence of extensive basal membrane infoldings, forming a close laminar membrane association with elongate, giant mitochondria. The third segment was composed of cells that showed a striking resemblance to teleost gill chloride cells, including their differentiation into inactive and active cell types. The inactive-type chloride cell, seemingly the more abundant form in both species, was large and cuboidal, containing an electron-transparent cytoplasm with numerous mitochondria concentrated in the basal three-quarters of the cell. The mitochondria were closely associated with an anastomosing tubular network very similar to that found in inactive chloride cells in the gill. By comparison the active-type chloride cell was small, with an extremely electron-dense cytoplasm, packed full with mitochondria and extensive anastomosing membrane networks. In attempting to correlate the occurrence of these kidney chloride cells with transport functions, total Na+/K+-ATPase and Ca2+-ATPase activities were determined and compared with the levels in the gills and kidneys of the Amazon osteoglossids. It was concluded that at least the Na+ transport potential of both the third segment and the gills can be varied either by increasing the size of the anastomosing tubular system or by increasing the proportion of active chloride cells maintained.
Pyruvate kinase from the liver and kidney of Arapaima gigas
Authors: Guderley H. , Fields J. H. A. , Cardenas J. M. , Hochachka P. W.
Published: August 2008

Pyruvate kinases from the kidney and liver of the osteoglossid Arapaima gigas were partially purified and characterized kinetically. The two enzymes have different elect rophoretic mobilities at pH 7.0, and while they share some qualitative similarities they show quantitative differences in their catalytic and regulatory properties. Both enzymes are activated by fructose 1.6-bisphosphate and inhibited by low levels of alanine and MgATP. The liver isozyme shows hyperbolic phosphoenolpyruvate binding, with a K1 for alanine inhibition of 0.7 mM and a K1 for MgATP inhibition of 1.0 mM. In contrast, the kidney isozyme shows cooperative phosphoenolpyruvate binding, which is accentuated at low levels of ADP. MgATP inhibition does not increase the cooperativity and shows an apparent K1 of 1.68 mM. The inhibition of alanine leads to considerable increases in the cooperativity and is effective at 1 mM and lower levels. Fructose 1.6-bisphosphate completely reverses the inhibition by alanine for both isozymes, while only leading to a partial reversal of the MgATP inhibition. These regulatory properties of both the kidney and the liver isozymes suit them for function in tissues which undergo both glycolysis and gluconeogenesis.
Relationship between phosphorylated metabolic intermediates and whole blood oxygen affinity in some air-breathing and water-breathing teleosts
Authors: Isaacks R. E. , Kim H. D. , Harkness D. R.
Published: August 2008

The relationship between whole blood oxygen affinity and erythrocyte (RBC) organic phosphate composition of three species of air-breathing teleosts (Lepidosiren paradoxa, Electrophorus electrocus, and Synbranchus marmoratus) and three pairs of closely related air-breathing and water-breathing fishes (Arapaima gigas vs. Osteoglossum bicirrhosom, Hoplerythrinus unitaeniatus vs. Hoplias malabaricos, and Pterygoplichthys sp. vs. Pseudoplatystoma sp.) have been studied.Packed cell volumes, hemoglobin concentrations, whole blood P50's, and total erythrocyte phosphates are higher in air breathers than in water breathers.GTP and ATP are the predominant organic phosphates in the erythrocytes of all of the species studied except A. gigas, which contains inositol pentaphosphate as the major organic phosphate at a level of 1.8 μmol/cm3 RBC or 39% of the total cell phosphate.
Observations on the life history of the caecilian Typhlonectes compressicaudus (Dumeril and Bibron) in the Amazon basin
Authors: Moodie G. E. E.
Published: August 2008

Ecological observations on the poorly known aquatic caecilian Typhlonectes compressicaudus are described. This species appears to be wholly adapted to an aquatic life style. The diet probably consists of aquatic invertebrates. The animal gives birth at the end of the dry season. The secretions of the poison glands are lethal to at least one species of predatory fish with which it coexists.
Alveolar and saccular lung phospholipids of the anaconda, Eunectes murinus
Authors: Phleger Charles F. , Smith David G. , Macintyre Douglas H. , Saunders Brian S.
Published: August 2008

Phospholipids and their mode of synthesis in lung samples from the alveolar and saccular regions of an anaconda (Eunectes murinus) were investigated by standard techniques of chloroform–methanol extraction and two-dimensional thin-layer chromatography. The alveolar lung has six times as much phosphatidylcholine in its lung wash lipid extract as saccular lung. Phosphatidylcholine and sphingomyelin are the two principal phospholipids of the tissue of both lungs. Alveolar lung incorporates a higher percentage although a smaller total amount of [1-14C]acetate (54%) into phosphatidylcholine (including lysophosphatidylcholine), whereas saccular lung only incorporates 8% [1-14C]acetate into phosphatidylcholine (including lysophosphatidylcholine) and 60% [1-14C]acetate into sphingomyelin. Saccular lung synthesized 31% disphosphatidylglycerol from [1-14C]acetate; alveolar lung did not synthesize any. Surface tension plots of lung wash lipid extracts show slight surpellic activity with minimum surface tensions of 22 dyn/cm (1 dyn = 10 μN) for both alveolar and saccular lung, at 37 °C.
Inositol disphosphate in erythrocytes of the lungfish, Lepidosiren paradoxa, and 2,3-diphosphoglycerate in erythrocytes of the armored catfish, Pterygoplichtys sp.
Authors: Isaacks R. E. , Kim H. D. , Harkness D. R.
Published: August 2008

Inositol diphosphate (inositol-P2) has been isolated and identified from erythrocytes (RBC) of the lungfish, Lepidosiren paradoxa. Inositol-P2 represents 6–8% of the total cell acid-soluble phosphates or 1.3 μmol/cm3 RBC. 2,3-Diphosphoglycerate (2,3-DPG) has been isolated and identified as a constituent of RBC of the armored catfish, Pterygoplichtys sp. 2,3-DPG is present in these cells at levels of 1.9 μmol/cm3 RBC or 11–14% of the cell phosphate. The possible role of these compounds as regulators of hemoglobin function in these species is discussed.
Taxonomy of mermithids (Nematoda: Mermithidae) of Canada and in particular of the Mackenzie and Porcupine river systems, and Somerset Island, N.W.T., with descriptions of eight new species and emphasis on the use of the male characters in identification
Authors: Mulvey R. H. , Nickle W. R.
Published: August 2008

Twenty-four described mermithids are listed as known members of the Canadian fauna. Five of these are redescribed, and eight new species are described; namely Capitomermis micropeos, Gastromermis plethelos, Gastromermis leptopeos, Gastromermis pachopeos, Hydromermis macrospiculatus, Neomesomermis leptoderos, Neomesomermis welchi, and Neomesomermis yukonensis. A taxonomic key is provided to separate the 10 genera to which the 24 species belong. Keys identify the species of the genera Gastromermis, Hydromermis, and Neomesomermis. Morphology of the male head and genitalia are critically analysed and consistent male characteristics incorporated into four keys.
The effects of numerical density of adult fish on reproduction and parental behavior in the convict cichlid fish Cichlasoma nigrofasciatum (Günther)
Authors: FitzGerald G. J. , Keenleyside M. H. A.
Published: August 2008

Basic reproductive and behavioral data were collected from pairs of Cichlasoma nigrofasciatum breeding under controlled conditions. Increasing the density of potential breeding pairs increased the level of territorial aggression and decreased reproductive success. Time spent with their young by parents did not vary consistently with density. The importance of the increase in aggression and its possible influence on reproductive success are discussed.
Redescription of a marine flatworm: Pseudoceros canadensis Hyman, 1953 (Polycladida: Cotylea)
Authors: Ching Hilda Lei
Published: August 2008

Specimens of Pseudoceros canadensis were studied alive, as stained whole mounts and sagittal sections, and with the aid of scanning electron microscopy. This species is oval in shape with frilled edges. The anterior marginal folds bear a pair of small, erect tentacles. The worms have a dorsal pattern of black spots and streaks, white dendritic or horizontal streaks in the medial area, and white spots towards the outer edges. Dorsal papillae, not previously described, are small, clear or white projections on the entire surface. They are nonciliated, epithelial extensions supported by parenchymal dorsoventral muscles. The dorsal epithelium also contains the tops of subepidermal gland cells, rhabdite-producing cells, ciliated columnar cells, and vacuolated cells. In contrast, the ventral surface is cream colored with the ruffled pharynx and highly muscular, central sucker appearing as prominent white organs. The ventral epithelium lacks papillae and has fewer rhabdite-producing cells. This species is found in association with tunicates on docks and in low intertidal to subtidal areas.
Life cycle of Truttaedacnitis stelmioides (Vessichelli, 1910) (Nematoda: Cucullanidae) in American brook lamprey (Lampetra lamottenii)
Authors: Pybus M. J. , Uhazy L. S. , Anderson R. C.
Published: August 2008

Field data from two populations of Lampetra lamottenii (Lesueur, 1827) in Ontario, combined with informattion from experimental studies, have provided the following explanation of the transmission of Truttaedacnitis stelmioides (Vessichelli, 1910). Eggs hatch on the stream bed in spring and early summer. Newly hatched larvae are ingested by filter-feeding ammocoetes and remain in the intestine throughout the summer. After developing to the third stage, larvae migrate via the bile duct to cystic ducts of the liver where they remain in a state of arrested development for up to 4 years. During transformation of the host, third-stage larvae apparently moult at least once in the liver, reenter the intestine, and develop to maturity in transformers and adult lampreys. Eggs are released into the lamprey intestine and eventually passed from the anus. Transmission occurs mainly in early summer. Truttaedacnitis stelmioides never becomes encapsulated in the gut wall of L. lamottenii although it may in other lamprey species. Lampetra lamottenii may be the most suitable host among the lampreys. The biology of the parasite is closely linked to the metamorphosis and maturation of the lamprey. Other cucullanids may have a similar relationship with their hosts. Possibly the cucullanids are basically heteroxenous in that they use the immature stage of the host (e.g. the ammocoete) as an intermediate host.
Evidence for pulmonary vasoconstriction during hypercapnia in the toad Bufo marinus
Authors: Smith D. G.
Published: August 2008

In this study, a photoelectric plethysmographic technique, in which the amplitude of the pulse wave obtained is decreased during vasoconstriction, was used to indicate changes in pulmonary vasomotor tone in response to hypercapnia in the toad Bufo marinus. Unilateral pulmonary ventilation with 1–5% CO2 in air produced a marked decrease in the pulsatile signal in both lungs, along with systemic hypertension and a slight bradycardia. The pulmonary response was prevented by either muscarinic blockade or pulmonary denervation and therefore involved the well-known vagal cholinergic constrictor innervation of the pulmonary artery. It has previously been shown that the cutaneous artery of B. marinus is not innervated by cholinergic constrictor fibres. Thus, in the present experiments, especially with a systemic hypertension, it is likely that CO2 would effect a shift of pulmocutaneous blood flow away from the lungs and towards the skin. Such a redirection of flow would be appropriate to the function of the skin as an alternative respiratory site during pulmonary apnea and is in accord with earlier findings that, in anurans, a high level of pulmonary vasomotor tone is maintained during apnea.
Records of horse flies and deer flies (Diptera: Tabanidae) in New Brunswick
Authors: Thomas A. W.
Published: August 2008

Forty-three species of tabanids in five genera are recorded from New Brunswick. Locality data, notes on seasonal distribution, and relative abundance are given. Modifications to keys of tabanids of the Maritime Provinces are given.
Some factors affecting reproduction and sex ratios in two species of predacious mites, Phytoseiulus persimilis Athias-Henriot and Amblyseius andersoni (Chant) (Acarina: Phytoseiidae)
Authors: Amano Hiroshi , Chant D. A.
Published: August 2008

Several factors were examined to determine their effect on the reproduction and sex ratios in two species of predacious phytoseiid mites, Phytoseiulus persimilis and Amblyseius andersoni, in the laboratory. The factors investigated included multiple matings, age of mating males, and food deprivation periods during the immature and adult stages. The results indicated that females of A. andersoni require multiple matings to maximize their reproductive potential but those of P. persimilis do not. Males of both species showed a high reproductive ability for more than 20 days and the total number of progeny produced by individual males exceeded 1000 and 500 in P. persimilis and A. andersoni respectively, under the experimental conditions. Following certain food deprivation programmes, females increased egg production and produced proportionally more male progeny, compared with females under constant conditions of abundant prey.
Head flicking by tent caterpillars: a defensive response to parasite sounds
Authors: Myers Judith H. , Smith James N. M.
Published: August 2008

Western tent caterpillars respond to sounds of 300–2100 Hz by head flicking. The sound frequencies to which they are most sensitive match the flight sound of a fly parasite which lays eggs on the heads of caterpillars. Caterpillars on tents are more likely to head flick when stimulated by sound and have lower parasitization levels than fifth-instar caterpillars which have left the tent.
Blood volume determination in the ringed seal, Phoca hispida
Authors: Aubin D. J. St. , Geraci J. R. , Smith T. G. , Smith V. I.
Published: August 2008

Red cell, plasma, and total blood volumes were determined in three ringed seals, Phoca hispida, through simultaneous labelling of both red cells and plasma. Total blood volumes were 139, 140, and 158 ml/kg of whole body weight ([Formula: see text] ml/kg). Lean body weight was determined in one seal; blood volume was calculated as 226 ml/kg lean body weight.
Morphology and taxonomy of Rhabdias spp. (Nematoda: Rhabdiasidae) from reptiles and amphibians of southern Ontario
Authors: Baker M. R.
Published: August 2008

Rhabdias americanus n.sp., Rhabdias ranae Walton, 1929, Rhabdias fuscovenosa (Railliet, 1899), and Rhabdias eustreptos (MacCallum, 1921) from amphibians and reptiles of southern Ontario are described. Rhabdias americanus n.sp. and R. ranae have two large lateral pseudolabia beside the oral opening whereas R. fuscovenosa and R. eustreptos each have six lips arranged in lateral groups of three. Rhabdias americanus n.sp. is distinguished from R. ranae by the shape of the pseudolabia and by the presence of a cuticular ring on the posterior border of the buccal cavity which is absent in the buccal cavity of R. ranae. Rhabdias fuscovenosa is distinguished from R. eustreptos by its significantly smaller size and by the shape of the posterior quarter of the body which is straight in R. fuscovenosa and corkscrew shaped in R. eustreptos. Rhabdias fuscovenosa is the only species examined in which eggs in the uteri of gravid hermaphrodites were always at an early cleavage stage of development. In other species examined most eggs in the uteri contained first-stage larvae.
Geographic variation in development time and predation in the tree-hole mosquito, Toxorhynchites rutilus septentrionalis (Diptera: Culicidae)
Authors: Trimble R. M. , Smith Stephen M.
Published: August 2008

In laboratory colonies of a northern (Newark, DE) and southern (Lake Charles, LA) population of Tx. r. septentrionalis the proportional increase or decrease in total development time with changes in temperature did not vary significantly. Between 13 and 27 °C, development of the third- and fourth-instar larvae, pupae, and preadults was completed more rapidly in the Delaware population. By contrast, Louisiana eggs embryonated more rapidly than Delaware eggs. Survival from the first instar to adult emergence was similar in both populations between 13 and 29 °C; however, all Louisiana larvae that pupated also emerged, whereas the emergence success of Delaware pupae declined with each 2 °C decrease in temperature between 23 and 13 °C. Louisiana larvae consumed more prey during development because they took longer to develop and because their daily rate of prey consumption was greater than that of Delaware larvae. Louisiana larvae partly consumed and killed without consuming more prey during development. These differences are discussed in relation to climatological and possible biological differences in the environments from which each population was derived.
Proteases of low molecular weight in the digestive fluids of decapods
Authors: Armstrong Jim R. , Villez E. J. De
Published: August 2008

There have been several reports of low molecular weight digestive proteases in the lobster, crab, and shrimp; two crayfish proteases ('alkaline' protease and 'niedermolekular' protease) have been characterized previously in independent investigations. Reciprocal isolation procedures used in the present study suggest that the crayfish enzymes are two preparations of one crustacean digestive protease.