bluuebunny/crossref_metadata_2025 huggingface dataset:
A cytotaxonomic investigation of seven species in the Eusimulium vernum group (Diptera: Simuliidae)
Authors: Hunter Fiona F. , Connolly Victoria
Published: August 2008

Using the banding pattern of Eusimulium vernum (Macquart) as a standard, the polytene chromosomes of seven North American members of the vernum group are described. These are Eusimulium aestivum (Davies, Peterson, and Wood), E. impar (Davies, Peterson, and Wood), E. gouldingi (Stone), E. croxtoni (Nickolson and Mickel), E. pugetense Dyar and Shannon, E. quebecense (Twinn), and an undescribed species provisionally designated Simulium sp. near furculatum/croxtoni. Two of these species, pugetense and quebecense, apparently are sibling species complexes. An inversion cladogram separates the seven species into two distinct lineages; aestivum, impar, pugetense, and quebecense belong to one and gouldingi, croxtoni, and Simulium sp. to the other.
The assessment of handling time in ruminants: the effect of plant chemical and physical structure on the rate of breakdown of plant particles in the rumen of mule deer and elk
Authors: Spalinger Donald E. , Robbins Charles T. , Hanley Thomas A.
Published: August 2008

The rate of breakdown of plant particles in the rumen of mule deer (Odocoileus hemionus) and elk (Cervus elaphus) was investigated to determine if plant chemical or structural composition affects processing or handling time in ruminants. Two hypotheses initially tested were that particle breakdown rates in the rumen were (i) directly related to their lignin concentration and (or) (ii) inversely related to their neutral detergent fiber concentration. The relative breakdown rate of a variety of dicot and monocot leaves and stems was an inverse function of lignin concentration, not a direct function as has been hypothesized. Neutral detergent fiber concentration was inversely related to breakdown rate. However, inconsistencies in the relation suggested a third hypothesis: the breakdown rate of the particles is directly related to mean cell wall thickness. Mean cell wall thickness was more closely related to differences in breakdown rate than any of the chemical variables measured and the relations between chemical variables and breakdown rate were a result of their covariation with mean cell wall thickness. We suggest that ruminants should select forages based in part on mean cell wall thickness and that handling time may have a significant effect on forage selection and intake.
A primer of bone names for the understanding of the actinopterygian head and pectoral girdle skeletons
Authors: Jollie Malcolm
Published: August 2008

The results of studies on the development of the bones of the head and pectoral girdle of several actinopterygians, assumed to represent a good sample of known variation, is summarized and combined with a group of anatomical accounts from the literature. Each bone is reviewed in terms of its variations, and its homology to that of other Osteichthyes is discussed. It is argued that there is a basic cranial and pectoral girdle pattern for Osteichthyes and that of the Actinopterygian is distinct in several particulars. These are enumerated. The teleost pattern is also discussed. It is proposed that a more detailed knowledge of the variation of cranial and pectoral girdle bones along with understanding of their development would have taxonomic value.
New evidence of high frequency of antler wounding in cervids
Authors: Geist Valerius
Published: August 2008

Seventy-two tanned, dehaired hides of four species of cervids from western Canada were examined for evidence of injuries. Combat injuries were segregated from injuries incurred from other sources. Forty-six of 55 males 1.5 years of age and older were scarred, as were 14 of 15 females. Of 15 males 1.5 years of age, 7 showed no scars, nor did two 6-month-old male fawns. Only 1of 22 male cervids over 2.5 years of age showed no combat scars. The frequency of wounding in males was 0–225, and in females0–18 per individual. About three-quarters of the scars were on the neck and haunches, about equally divided between these areas. The longest healed scar measured 420 mm; about 20% of the scars exceeded 100 mm in length. Field observations greatly underestimate wounding in cervids. A few males appear to opt out of rutting, but opt in when opportunity allows. The "dove" strategy is rare, but evidence from hides indicates that it does exist, confirming field observation.
Fine structure of aesthetasc chemoreceptors in the crayfish Orconectes propinquus
Authors: Tierney Ann Jane , Thompson C. S. , Dunham D. W.
Published: August 2008

The outer antennular flagella of decapod crustaceans bear chemoreceptive hairs called aesthetascs. In the crayfish Orconectes propinquus these sensilla are located ventrally on the 11–13 most distal segments of the outer flagella. Two clumps of 3–6 aesthetascs occur on each segment, giving a total of approximately 80 aesthetascs per outer flagellum. Aesthetascs are100–150 μm long and about 12 μm in diameter. Each has a single annulation 30 μm from the hair base. The sensilla arise from immovable sockets and are directed distally at a 45° angle to the main body of the antennule. Aesthetascs lack an apical pore. However, the distal portion of each sensillum has thin cuticular walls which are readily penetrated by dye; this is probably the site where chemical stimuli enter. In O. propinquus each aesthetasc is innervated by 40–110 sensory neurons. Each neuron gives rise to a dendrite that branches into two cilia (9 × 2 + 2 structure; 0.15–0.20 μm in diameter). No further branching of outer dendritic segments occurs and thus each aesthetasc contains 80–220 sensory endings. Within the antennule lumen the dendrites are surrounded by two sheath cell layers, an inner layer and an outer layer. The inner sheath cells ascend 50 μm into the aesthetasc lumen; the outer sheath cells terminate at the sensilla bases. The outer dendritic segments gradually taper in diameter and terminate 25 μm from the sensilla tips.
Status of Eustilicus Sharp, Trochoderus Sharp, Deroderus Sharp, and Stilocharis Sharp (Coleoptera: Staphylinidae: Paederinae: Paederini) with implications for classification of the Medonina and Stilicina
Authors: Frania Henry E.
Published: August 2008

Based on a study of adults, Trochoderus Sharp and Stilicolina Casey are placed as subjective synonyms of Eustilicus Sharp, Lypomedon Blackwelder is removed from Stilomedon Sharp and treated as a subjective synonym of Deroderus Sharp, Stilocharis Sharp is removed from Lithocharis Dejean and treated as a distinct genus, and Deroderus difftcilis Sharp is transferred to Rugilus Leach. Diagnoses are provided for Eustilicus, Deroderus, Stilocharis, Rugilus, and Stiliderus Mots. Although Eustilicus, Rugilus, and Stiliderus are typical members of the subtribe Stilicina, and Stilocharis and Deroderus are typical Medonina, adults of Eustilicus, Stilocharis, and Deroderus possess two synapomorphies to the exclusion of all other Paederinae. Evidently Eustilicus is more closely related to Deroderus and Stilocharis than to Rugilus or other genera in the Stilicina. Further studies may show that the Stilicina and Medonina should be combined.
Effects of adrenergic drugs on the coronary circulation of Atlantic salmon (Salmo salar)
Authors: Farrell A. P. , Graham M. S.
Published: August 2008

Spontaneously beating hearts from Atlantic salmon (Salmo salar) were used to examine the adrenergic regulation of the perfused coronary circulation. Excitatory α-adrenoceptors (vasoconstriction) dominated over inhibitory β-adrenoceptors (vasodilatation). Increased heart rate via β-adrenergic stimulation was possible with drug injections into the coronary artery. The heart rate effects followed the vasoactive effect by approximately 2 min.
Studies on the energy metabolism in the isolated, perfused Rana ridibunda heart
Authors: Lazou A. , Beis I.
Published: August 2008

In the isolated, perfused Rana ridibunda heart, the concentrations of the metabolites were measured as a function of time, under increased heart work. The changes in tissue contents of adenine nucleotides were time dependent. ADP, AMP, and inorganic phosphate levels increased simultaneously, while ATP and creatine phosphate levels decreased. The tissue contents of hexose monophosphates and citrate decreased and contents of fructose bisphosphate, lactate, and pyruvate rose. A comparison of mass action ratios with apparent equilibrium constants for the glycolytic reactions indicated that phosphoglucose isomerase, aldolase, triosephosphate isomerase, and lactate dehydrogenase reactions are close to equilibrium, while phosphofructokinase is displaced from equilibrium. During increased heart work, changes in the tissue contents of adenine nucleotides and citrate appeared to play a role in the regulation of glycolysis at the level of phosphofructokinase activity. From the results, it appears that in amphibian heart, glycolysis seems to be similar to that of mammalian heart as far as control is concerned, in spite of its structural and functional differences.
Seasonal differences in courtship feeding rates of male common terns
Authors: Morris Ralph D.
Published: August 2008

Courtship feeding rates by male common terns (Sterna hirundo) nesting late in the 1982 breeding season were markedly lower than those of peak nesters in that year. In 1983, however, there were no differences in courtship feeding rates between peak and late nesters. Both groups of males in 1983 fed females at similar rates before the first eggs were laid, and both rates declined after the second eggs were laid. Larger fish were fed to the females later in the season. Late nesting males adjusted their feeding rates to the size of fish delivered; males feeding larger fish fed them at a lower rate than males feeding smaller fish. There was no difference in the weights of three-egg clutches laid by peak and late nesting females, and there was no correlation between courtship feeding rate and clutch weight. As all females were apparently able to obtain sufficient nutrition to provision their eggs adequately, I suggest that 1983 was an unusually favourable food year at Port Colborne. This view accepts courtship feeding as an adaptation enabling the female to obtain sufficient nutrients before and during egg laying. Other functions of the behaviour at other times during a breeding bout are not precluded.
Modulation of reproductive output in Drosophila by spectral properties of ambient light
Authors: Buhr Bruce , Wiens Wayne , Dirks Marvin , Riordan Hugh
Published: August 2008

The net reproductive output was determined for two strains of Drosophila melanogaster, wild-type (+) and white-eyed (w), under conditions of varied wavelength and intensity of illumination. The reproductive output of wild-type flies raised under blue light (max. 470 nm) was significantly lower (p < 0.01) than that of organisms grown under red (max. 630 and 660 nm) or green(max. 530 nm) illumination, or under conditions of total darkness. In contrast, blue light did not depress the reproductive output of white-eyed flies. The differential reproductive response of the two strains, then, appears to be related to genetically determined properties of the eye. Changes in the radiant fluence rate over a 10-fold range were not found to significantly modify reproductive output of wild-type flies, and if flies were illuminated with red, green, or blue light at identical fluence rates, those under blue, again, had a significantly lower (p < 0.01) reproductive output than the other two. The data suggest that the emission spectrum, not the radiant light intensity, significantly affects the number of offspring produced per parent.
Carbon dioxide excretion in fishes
Authors: Perry S. F.
Published: August 2008

The pattern and control of carbon dioxide excretion in fish is reviewed with particular emphasis on the site(s) of bicarbonate dehydration, the involvement of diffusive and convective processes, and the relationship with ionic and acid–base regulation. The principal route for carbon dioxide excretion in fish involves the catalysed dehydration of plasma bicarbonate within erythrocytes to form physically dissolved CO2 and the subsequent diffusion of physically dissolved CO2 across the gill epithelium. It is likely that bicarbonate entry into the erythrocyte in exchange for intracellular chloride, rather than branchial CO2 diffusion or blood/water convection, is the rate-limiting process in carbon dioxide excretion, although a change in any one of these factors will affect overall CO2 elimination. Additionally, a relatively minor amount of CO2 is hydrated within gill epithelial cells to form H+ and HCO3− ions that are exchanged for Cl− ions and Na+ ions, respectively. Evidence is presented indicating that branchial and erythrocytic HCO3−/Cl− exchanges are under adrenergic control and that modulations of these processes by elevated levels of circulating catecholamines may be important in regulating acid–base disturbances.
Scent rubbing in wolves (Canis lupus): the effect of novelty
Authors: Ryon Jenny , Fentress J. C. , Harrington F. H. , Bragdon Susan
Published: August 2008

Two groups of wolves (Canis lupus) (N = 15 individuals) were tested for scent rubbing with eight novel odours from four classes of scent (herbivore, carnivore, food, and manufactured). If novelty is the primary factor influencing scent rubbing, we expected high initial rubbing frequencies across classes that would decline with successive presentations. Differential responses would indicate class of scent is more important. The wolves exhibited a striking propensity to scent rub differentially among odours. The manufactured odours (perfume and motor oil) elicited the strongest rubbing response, carnivore odours (cougar (Felis concolor) feces and black bear (Ursus americanus) feces) elicited the second highest response, and one of the food odours (salt pork) elicited a single rub from one individual, while the other food odour (tuna oil) was not rubbed. Herbivore odours (Aoudad sheep (Ammotraqus lervia) feces and Sable Island horse (Equus caballus) feces) were not rubbed. There was a negative correlation between odours that were rubbed and those tasted. Overall, there was a slight tendency to rub less frequently on an eliciting odour with successive presentations, but a stronger tendency with the two odours that elicited the greatest rubbing response (perfume and motor oil). Scent rub eliciting odours might include (i) scents of a class not usually encountered in the wolf's environment, (ii) a familiar scent that deviates from the norm by a change in character, and (iii) scents to which a wolf might have a strong aversion or attraction.
Observations on the ectoparasites of some Newfoundland passerines (Aves: Passeriformes)
Authors: Wheeler Terry A. , Threlfall William
Published: August 2008

A total of 144 birds (17 species) were mist-netted in June and July 1984 on the Avalon Peninsula, Newfoundland, and examined for ectoparasites; 139 birds (96.5%) of 17 species were found to be infested. Biting lice (Mallophaga: 6 genera) were recovered from 59 (41.0%) of the birds, fleas (Siphonaptera: 1 genus) from 19 (13.0%), and hippoboscids (Diptera: 1 genus) from 2 (1.4%). Mites (Acarina: 8 genera) were the most frequently encountered parasites, with 137 (95.1%) of the hosts being infested. The prevalence of Mallophaga was similar to that recorded by other workers. Nymphs and females constituted the most prevalent mallophagan age-classes, which suggests that an increasing louse population is coincident with the host breeding season. No significant differences were noted in the prevalence of parasites on male and female birds or on adult and immature birds. Ground-feeding passerines showed the highest prevalence, intensity, and diversity of infestation by Mallophaga, as well as the greatest degree of similarity in ectoparasite fauna between species. Host specificity is discussed, and ecological factors in addition to host phylogeny are considered to play a role in determining the parasite fauna of a given bird species. The collection technique used was evaluated and found to be adequate for the processing of large numbers of birds when both qualitative and quantitative data on certain ectoparasitic groups are to be collected.
Temporal patterns of host-seeking activity of mosquitoes in Algonquin Park, Ontario
Authors: Trueman David W. , McIver Susan B.
Published: August 2008

Using multidirectional ramp traps baited with CO2, the flight activity of mosquitoes was monitored on a continuous basis for two seasons, with samples segregated into 30-min catches. Over 16 000 catches were collected, from which 22 species of mosquitoes were identified. Seasonal extrema are reported for all mosquito species collected and detailed seasonal and daily patterns of activity are given for the six most abundant species, namely Aedes canadensis (Theobald), Aedes communis (DeGeer), Aedes diantaeus Howard, Dyar and Knab, Aedes intrudens Dyar, Aedes punctor (Dirby), Aedes abserratus (Felt and Young), and Mansonia perturbons (Walker). All six abundant species had a peak of activity in the evening: A. communis the earliest, around 1800, and M. perturbons the latest, around 2200. Mansonia perturbons was the only species with a distinct peak of early morning activity, although some activity was evident for other species. Perspective plots for A. communis and M. perturbons are used to examine relationships between seasonal and daily patterns. There was a detectable change through the season in the daily pattern of A. communis, but no change was detected for M. perturbons.
Dispersion of common merganser (Mergus merganser) breeding pairs in relation to the availability of juvenile Pacific salmon in Vancouver Island streams
Authors: Wood C. C.
Published: August 2008

Common merganser (Mergus merganser) breeding pairs and broods were censused on eight coastal streams on Vancouver Island to evaluate the relative importance of the number of potential breeding pairs, stream size, and the availability of juvenile Pacific salmon in limiting merganser breeding density. The number of potential breeding pairs did not limit nesting density on at least one stream where juvenile salmon populations were enhanced by a hatchery and spawning channel. At distances > 1 km above tidal influence, breeding pairs were evenly dispersed along the streams during the peak egg-laying and incubation period at maximum densities of 0.4–1.4 pairs/km. Maximum breeding pair counts were higher and more variable among streams on the lower kilometer of freshwater (1–9 pairs) and on tidal waters near the stream outlets (4–9 pairs). Stream size accounted for only a part of the variation in breeding pair counts. The estimated number of broods produced on each stream was highly correlated (r = 0.95) with both drainage area and juvenile salmon production, including production from hatcheries. Possible mechanisms relating the dispersion of breeding pairs to the availability of juvenile salmon are discussed. A "food assessment" hypothesis, whereby breeding pairs choose a nesting stream on the basis of prey availability during the nesting season, could not be rejected on the basis of predictions about hatching dates and duckling survival. This hypothesis has serious implications for mortality of wild salmonids in hatchery-enhanced streams.
The rodlet cell of Semotilus atromaculatus and Catostomus commersoni (Teleostei): studies on its identity using histochemistry and DNase I – gold, RNase A – gold, and S1 nuclease – gold labeling techniques
Authors: Barber D. L. , Westermann J. E. Mills
Published: August 2008

Rodlet cells, enigmatic, variably present components of several teleost epithelia, have been regarded as normal cells of unknown function or parasites of unknown phylogeny. The present study examines rodlet cells in the northern creek chub, Semotilus atromaculatus, and the white sucker, Catostomus commersoni. In light microscopic histochemistry, rodlet cores give "RNA-type" reactions to acridine orange and methyl green – pyronin procedures, but in electon microscopy, application of the nuclease–gold procedure shows that rodlets contain DNA in a helical distribution at the core boundary, but not RNA. Rodlet cores also are labeled by S1 nuclease – gold, an enzyme that is specific for single-stranded DNA. We have concluded that DNA, and only DNA, is found in the rodlet, and that it occurs in a conformation not normally seen in the eukaryote nucleus. In fact, the rodlet with its DNA resembles no known eukaryote, prokaryote, or virus. Discussion includes the possibility that the rodlet core may be a natural example of DNA containing left-handed sequences (Z-DNA). Since the nucleus of the rodlet cell contains the same amount of DNA as nuclei of teleost cells, the cell itself is concluded to be of teleost origin, and the rodlets are proposed to be invasive structures of unknown phylogeny which convert the metabolism of the teleost cell to rodlet production.
A review of the systematics and distribution of Chydorus ventricosus Daday, 1898, with the first description of the male and redescription of the species
Authors: Rajapaksa R. , Fernando C. H.
Published: August 2008

Based on the study of the type series and material from Sri Lanka, a comprehensive description of Chydorus ventricosus Daday is given including the first description of the male. The detailed morphology of all instars of females and males, population structure, and some biological notes are also provided. This species was considered a tropicopolitan species based on previous records from Asia, America, and Africa. However, a detailed study of populations from a wide area of the Oriental region and material previously designated as Chydorus ventricosus from America and Africa, and a critical review of the literature indicates that it is very probably restricted to the Oriental region. Chydorus ventricosus closely resembles an undetermined number of taxa. Only a detailed study will determine their status. We have compared it with the only two well-described, closely related species. The present study has characterized all stages of Chydorus ventricosus. This will enable accurate diagnosis of this species.
Ommatokoita sp. (Copepoda: Lernaeopodidae) parasitic on a demersal shark, Etmopterus princeps, from the northwest Atlantic Ocean
Authors: Hogans W. E. , Brattey John
Published: August 2008

Ommatokoita sp. is described from a single adult female specimen recovered from the skin of the demersal shark Etmopterus princeps collected in the northwest Atlantic Ocean. The specimen differs from the other species of the genus Ommatokoita, O. elongata, in the shape of the trunk, the structure of the first maxillae and maxilliped, and the size of the parasite.
The influence of early experience on escape behaviour in the guppy (Poecilia reticulata)
Authors: Goodey Wayne , Liley N. R.
Published: August 2008

Guppies (Poecilia reticulata) with or without experience of being chased by adult conspecifics were exposed first to a model "aerial predator" to assess the magnitude of their escape response, then to live piscivorous fish to assess their escape ability. Early experience had some influence on response magnitude but a greater influence on escape ability. Guppies that were chased when young by adult conspecifics required significantly more attacks before they were captured than either guppies that had no experience of being chased or guppies exposed to only visual or chemical cues associated with chasing by adults. Conditioning of predator-avoidance behaviour by early exposure to chasing by potential predators may be an advantage in the physically and biotically heterogeneous environments occupied by the guppy, and chasing by adult conspecifics may provide part of the learning experience.
Contribution of shivering in leg muscles to heat production in Japanese quail
Authors: Stevens E. Don , Ferguson J. , Thomas V. G. , Hohtola E.
Published: August 2008

We estimated heat production in Japanese quail (Coturnix coturnix japonica) by measuring oxygen uptake using open-circuit respirometry as ambient temperature was decreased gradually from 26 to 3.5 °C. At the same time, the intensity of shivering was estimated in both the leg muscles and the flight muscles by measuring electromyograms. Metabolic heat production increased in a linear fashion as ambient temperature decreased. Shivering intensity increased at the same linear rate in the leg muscles as in the flight muscles as ambient temperature decreased. The leg muscles produce a substantial fraction (about 1/4) of the total shivering heat production at low ambient temperatures. Shivering occurred in bursts; the onset of a burst in the leg muscles was precisely synchronized with the onset of a burst in the flight muscles.
Reproductive ecology of the painted turtle (Chrysemys picta marginata) in southwestern Quebec
Authors: Christens Elaine , Bider J. Roger
Published: August 2008

The reproductive ecology of painted turtles (Chrysemys picta marginata) was studied over 3 years (1983–1985) in southwestern Quebec. We used X-ray photography to determine clutch size, egg size, and clutch frequency in conjunction with radiotelemetry to determine when and where the eggs were being deposited. Data on nesting frequency indicated that between 40 and 80% of the 7- to 11-year-old females reproduce each year. All females > 11 years of age reproduced each year and exhibited a substantial reduction in growth compared with younger adult females. The percentage of those females that layed two clutches in a season ranged from 5 to 32%. There was no difference in the size of the first and second clutches or those produced by females only laying one clutch. The average clutch size was found to be 9.2 (range, 5–12) eggs. There was no significant relationship between clutch size and body size, between clutch size and age, or between clutch size and egg size. There was a significant positive linear relationship between egg size and body size. Age-specific fecundity increased up to 20 years of age and then decreased. When compared to studies of more southern populations of painted turtles, the major reproductive strategy for this population seems to be to produce a larger number of large eggs per clutch.
Morphological variability in Echinorhynchus gadi, E. leidyi, and E. salmonis (Acanthocephala: Echinorhynchidae) from fishes in northern Canadian waters
Authors: Shostak Allen W. , Dick Terry A. , Szalai Alexander J. , Bernier Lionel M. J.
Published: August 2008

Morphological variability of Echinorhynchus gadi, E. leidyi, and E. salmonis was evaluated from 30 collection sites in northern Canada. Nine new hosts were recorded. Mixed infections with the three species, in addition to their high morphological variability, made the identification of Echinorhynchus spp. from northern waters unreliable in the absence of information on morphological variability from local and geographically distant populations. Worm age, host species, and geographic location contributed to the variability of several taxonomically important characters: proboscis size and shape, hook size and number, body shape, and egg size. These characters had considerably greater variability and interspecific overlap in ranges than previously reported. Identifications were most reliable when based on gravid females. Individual males and immature females could generally be identified, with about 90% or greater reliability, using a multivariate comparison of proboscis measurements to a data set based on gravid females from the entire study area. Meristogram analysis revealed some intraspecific similarities and interspecific differences in proboscis hook shape but patterns varied geographically. While meristograms corroborated specimen identifications based on more comprehensive analyses, they were unreliable, when used alone, on Arctic and north temperate populations of echinorhynchids. Morphological variability between populations of Echinorhynchus spp. in different lakes was greater than could be accounted for by host species and the environment. It is hypothesized that this geographic variability may be a consequence of restricted gene flow between isolated populations causing geographic isolation of morphological variants.
Natal nest location and small mammal tracking with a spool and line technique
Authors: Boonstra Rudy , Craine Ian T. M.
Published: August 2008

We describe a simple, inexpensive method for tracking small mammals accurately for distances up to 180 m. A small spool of thread is attached to the back of the animal with srgical glue. As the animal moves along, it leaves behind it a trail of thread that can be followed along the route taken and to nest sites. Of 157 lactating meadow voles spooled, we found 62 nests with young. This success rate can probably be doubled by reducing two sources of spooling failure and by spooling a second time within the same trapping session.
Vision is not necessary for size-selective zooplanktivory in aquatic salamanders
Authors: Lannoo Michael J.
Published: August 2008

Vision is usually implicated as the sensory modality employed in size-selective zooplanktivory by aquatic vertebrates. I tested this generalization for nocturnally active salamanders by offering sighted and enucleated Ambystoma maculatum larvae a choice of large vs. small, or normally coloured vs. artificially darkened Daphnia, a natural prey. Salamanders in all treatments took the largest Daphnia and exhibited similar high feeding rates. There was no preference for artificially darkened Daphnia, as would be expected if visual cues predominate. Together these results indicate that vision is not exclusively responsible for size-selective predation by nocturnal salamanders. The often stated or implied assumption that size selectivity indicates visual predation in aquatic vertebrates should thus be questioned.
The influence of roost closure on the roosting and foraging behaviour of Eptesicus fuscus (Chiroptera: Vespertilionidae)
Authors: Brigham R. Mark , Fenton M. Brock
Published: August 2008

We used radio tracking and direct observation to determine the effect of roost closure on the roosting and foraging behaviour of big brown bats (Eptesicus fuscus) in maternity colonies near Ottawa. Individuals were site loyal, but after eviction they moved short distances to new roosts where they tended to produce fewer offspring. The time spent on the first foraging flight, the maximum distance travelled, and the use of feeding areas did not change with exclusion. The results suggest that bats roost to take advantage of site-specific factors that may increase reproductive success.
Annual variations in reproductive characteristics of painted turtles (Chrysemys picta)
Authors: Schwarzkopf Lin , Brooks Ronald J.
Published: August 2008

In Algonquin Park, Ontario, body size and clutch characteristics were recorded for 51 female painted turtles (Chrysemyspicta) in 1983, 61 in 1984, and 24 in 1985. Clutch size, clutch mass, and egg width correlated significantly with body size (carapace length) in all 3 years. Egg length and egg mass were significantly related to body size in 1984 and 1985, but not in 1983. There were no significant correlations of egg width or egg mass to clutch size. For a group of the same individuals compared by repeated-measures ANOVA, mean clutch mass and mean egg size, but not mean clutch size, varied significantly among years. Correlation of egg size with body size, lack of correlation between egg size and clutch size, and annual variation in egg size, but not clutch size, all fail to support current versions of optimal egg size theory. Twenty-six females nested in both 1983 and 1984 and 11 females nested in both 1984 and 1985. Fourteen females nested twice in 1 year: six in 1983 and eight in 1984. Between 43 and 73% of adult females nested in a given year and 12–13% nested twice in a single season. These estimates are similar to those reported for other populations of this species. It appears that variations in both clutch size (frequency) and egg size are important sources of variation in reproductive output.
A key to the Mysidacea of the Pacific Northwest
Authors: Daly Kendra L. , Holmquist Charlotte
Published: August 2008

A key to 28 species of Mysidacea of the coastal and inland waters of Oregon, Washington, and British Columbia is presented. The literature on taxonomic revisions, continuing taxonomic problems, and recently described species is reviewed. Diagnostic illustrations and an annotated species list containing the geographic distribution and general ecology of each mysid are also included.
Effects of extra food on small rodents in a south temperate zone habitat: demographic responses
Authors: Young Brenda L. , Stout Jack
Published: August 2008

Demography of Peromyscus gossypinus, Ochrotomys nuttalli, Peromyseus floridanus, and Glaucomys volans was studied for 2 years on replicate grids in sand pine scrub habitat in central Florida. After 1 year, sunflower seeds were provided to the rodent on one grid. Minimum numbers of P. gossypinus increased an average of 46% on the food supplement grid, whereas numbers on the control grid declined 27%. The population increase was due to immigration. Abundance of O. nuttalli was not increased by the supplemental food; however, survival was enhanced and within-grid movements were reduced. Peromyscus floridanus appeared on the study area during the experiment, but failed to establish a resident population. Because the supplemental food was not directly accessible to G. volans, no response to its presence was observed. Ochrotomys nuttalli appeared not to be food limited under the conditions of the experiment, whereas P. gossypinus appeared to be food limited.
Ecology of the sagebrush vole (Lemmiscus curtatus) in southeastern Idaho
Authors: Mullican Tim R. , Keller Barry L.
Published: August 2008

Populations of Lemmiscus curtatus were monitored on three study plots in sagebrush steppe of southeastern Idaho over a 13-month period. Average densities of Lemmiscus ranged from 4 to 16/ha. Sagebrush voles bred during winter after a period of population decline and prior to a population increase. Summer median weights at sexual maturity were 14.6 g for males, 16.4 g for females, and did not differ significantly. Tagging with 182Ta showed that sagebrush voles occurred singly or in pairs during the summer rather than in colonies as suggested by previous investigators. Food habit analysis revealed that the most common food items in June and August were Castelleja sp. and Lupinus sp., respectively.
Effects of a short-term experimental acidification on a microinvertebrate community: Rhizopoda, Testacea
Authors: Costan Georges , Planas Dolors
Published: August 2008

The effects of a short-term acidification on the density and diversity of testate Amoebae (Protozoa: Rhizopoda, Testacea) were investigated in seminatural conditions using an experimental set-up simulating a lotic ecosystem. Decreases in density were observed during sulfuric and nitric acid treatments (highly significant differences in the acidified channels compared with the nonacidified control channel). Diversity fluctuates with regard to variations in its two components, evenness and number of species. The reponse is qualitatively different (specific richness) but quantitatively nonsignificant (density), depending to the type of acid used.
Influence of water temperature on behavioural interactions between juvenile brook charr, Salvelinus fontinalis, and rainbow trout, Salmo gairdneri
Authors: Cunjak Richard A. , Green John M.
Published: August 2008

Interspecific behavioural interactions between paired brook char (Salvelinus fontinalis) and rainbow trout (Salmo gairdneri) were compared at different water temperatures to test the hypothesis that a species realizes a competitive advantage within its optimal thermal range. Three test temperatures were used: 19 °C (optimal temperature for rainbow trout), 13 °C (optimal temperature for brook charr), and 8 °C (below the optima for both species). Brook charr dominated rainbow trout at both 8 and 13 °C. At 19 °C, neither species displayed an obvious competitive advantage. The time (days) to the establishment of a dominance hierarchy reflected specific optimal temperatures; it was shortest for rainbow trout and brook charr at 19 and 13 °C, respectively. The implications of optimal temperatures and competitive ability are discussed in relation to habitat partitioning in the stream environment.
Factors affecting roost departure and entry by wintering merlins
Authors: Warkentin Ian G.
Published: August 2008

Merlins (Falco columbarius) overwintering in Saskatoon, Saskatchewan, depended upon mature spruce trees, planted in residential areas of the city, for roosting sites. Variation in entry times at the roost by radio-tagged Merlins was accounted for by sunset time, total daily solar radiation, and temperature. To a lesser extent the variation in departure times was explained by sunrise time and temperature. Merlins left the roost significantly earlier as the days became shorter in the period leading up to the winter solstice, but returned at the same time relative to sunset resulting in a longer active phase than that provided by natural day length.
A new species of Phyllodistomum Braun, 1899 (Digenea: Gorgoderidae) in a Neotropical catfish, with discussion of the generic relationships of the Gorgoderidae
Authors: Brooks Daniel R. , Macdonald Cheryl A.
Published: August 2008

A new species of Phyllodistomum is described. Collected from the doradid catfish Trachycorystes insignis in western Colombia, Phyllodistomum mayesi sp. n. resembles P. spatula, P. spatulaeforme, and P. symmetrorchis by having postovarian vitellaria but differs by possessing an acetabulum significantly smaller than the oral sucker. The phylogenetic relationships of 14 genera of gorgoderids are analyzed using a suite of 19 homologous series derived from comparative morphology. The resulting phylogenetic tree has a consistency index of 77%, comparable to those found in studies at the familial and subfamilial level among digeneans. The genus Phyllodistomum has no autapomorphies and thus no support as a natural group. A classification of the Gorgoderidae is proposed. A key to the 14 genera is provided.
Laboratory observations on emergent patterns of juvenile Atlantic salmon, Salmo salar, relative to sediment loadings of test substrate
Authors: MacCrimmon Hugh R. , Gots Barra L.
Published: August 2008

Effects of various loadings of a test gravel incubation substrate (32- to >4-mm pebble) with a single sediment mix (<0.25- to 4-mm sand) were examined in vertical flow incubators at a constant temperature (9.9 °C) and flow rate (200 mL min−1). Mean survival (75%) from ova burial to juvenile emergence was not influenced significantly by different sediment loadings. However, time to first and median emergence, duration of emergence, stage of development at emergence, and within-substrate behaviour were each correlated positively with mean particle size (r ≥ 0.72) and negatively with sediment loading rates (r ≥ −0.68).
Sex ratio regulation in Brachymeria intermedia, a pupal gypsy moth parasitoid
Authors: Mohamed M. A. , Coppel H. C.
Published: August 2008

The solitary pupal gypsy moth endoparasitoid, Brachymeria intermedia (Nees) (Hymenoptera: Chalcididae), regulates the sex ratio of its progeny such that the ratio is generally female skewed. Parents with a male-skewed sex ratio produce progeny that are female biased more than parents with a female-skewed sex ratio. Variables such as host size, host density, and intraspecific competition played no role in determining the sex ratio of the progeny. We conclude that sex ratio regulation of the progeny in this species is a function of male density.
Interference of copulation in a colony of marked black-legged kittiwakes
Authors: Chardine John W.
Published: August 2008

During behavioural observations (1979–1981) at a colony of black-legged kittiwakes (Rissa tridactyla) nesting on the window ledges of a warehouse, some breeding and nonbreeding males interfered with the copulations of conspecific colony members. The proportion of copulations interfered with varied from 15 to 27% depending upon year. Four types of interference were identified. Interference stopped 51% of copulations and temporarily halted another 37%. Some interfering birds were individually identified by colour bands or other unique features. Identified males seen to interfere at least once did not differ significantly with respect to breeding experience from those never seen to interfere, but the former group had paired with their mates for significantly fewer years than the latter. The majority of interferences by breeding males were performed during the 2-week period before their mates laid eggs: a period coincident with peak rates of copulation for these pairs. The results are used in an evaluation of hypotheses for the adaptive function of interference behaviour.
The effect of oxygen availability on the osmoregulatory contribution of free amino acids in Acanthamoeba castellanii
Authors: Geoffrion Yves , Guderley Helga , Larochelle Jacques
Published: August 2008

In Acanthamoeba, the availability of oxygen markedly affects the response to hyperosmotic (250 to 500 mosmol/kg water) or hypoosmotic (250 to 125 mosmol/kg water) stress. The short-term recovery of cell hydration after hyperosmotic shock was more rapid at a [Formula: see text] of 54 Torr (1 Torr = 133.322 Pa) than at 5 Torr, despite similar increases in the free amino acid content of the cell (2.3- to 2.4-fold). Under anoxia, the early response to both hyper- and hypo-osmotic stress resulted in osmometer-like cells and the osmoregulatory contribution of the free amino acid pool following hyperosmotic shock was totally abolished. After a hypoosmotic shock under anoxia, however, the decrease of the free amino acid pool, though much slower, was of the same magnitude as under aerobic conditions (1.8- to 2.5-fold). This was apparently the only osmoregulatory mechanism operative in the absence of oxygen. The free amino acid pool was qualitatively affected by the oxygenation level, with proline being more abundant at high [Formula: see text] and alanine being more important under low [Formula: see text] and anoxia. The oxygen consumption of the cells was essentially unaffected by osmotic stress and by the [Formula: see text] level. The osmotically induced changes in the free amino acid content of the cell involve flows of energy into and out of the free amino acid pool that appear considerable when compared with the energy available from oxidative metabolism. This suggests that de novo synthesis and complete oxidation have only a limited role in the supply and disposal of the free amino acids involved in osmotic regulation.
Ecology and coexistence of two species of Brachycentrus (Trichoptera) in a Rocky Mountain river
Authors: Hauer F. Richard , Stanford Jack A.
Published: August 2008

Life-cycle dynamics, growth rates, and relative abundance of Brachycentrus occidentalis and Brachycentrus americanus were studied over a 3-year period in the Flathead River, Montana. Brachycentrus occidentalis appeared as early instar larvae in mid to late summer, grew rapidly during autumn, and reached fourth and fifth instars prior to winter conditions. Most larvae remained active until mid-spring and the onset of spring runoff. Individuals pupated during late April through May and adults emerged after peak runoff in mid-June. Brachycentrus americanus larvae appeared as first instar larvae in autumn and overwintered as early instars. Larvae grew rapidly during spring as temperatures began to rise, but growth was discontinued during spring runoff. Larvae completed growth during summer after the runoff period and emerged in late August and early September. Growth patterns and emergence of both species occurred primarily during fall or spring and late summer, with little growth during winter or spring freshet. Thus growth was associated with quantitatively similar but temporally different periods of organic seston, temperature, and moderate flow.
Length of breeding life of coho salmon (Oncorhynchus kisutch)
Authors: Berghe Eric P. van Den , Gross Mart R.
Published: August 2008

Since Pacific salmon (Oncorhynchus spp.) die on the breeding grounds after spawning, duration of individual life may affect survival of deposited eggs. In addition, breeding life of both sexes has implications for estimates of size of spawning populations. We therefore examined the contributions of body size, population density, water level, season, and year to length of breeding life in individual coho salmon (O. kisutch). Age 3 breeding males and females lived an average of 9 days (range, 2–30 days), and 2-year-old "jack" males averaged 8 days (range, 2–21 days). Sixteen percent of the variance among age 3 males and 44% of the variance among females could be explained by the variables examined. Density of adults made a significant negative contribution to life-span, while water level, season, and year were insignificant. Body size was the most important variable in explaining breeding life-span, being positively related and accounting for 10% and 36% of the variance in 3-year-old males and females, respectively. In contrast, none of these variables explained the observed variation in jack male breeding life. The differences between the sexes and between 2- and 3-year-old males are consistent with levels of competition on the breeding grounds. We show that the results on individual body size and breeding life span can be used to offset biases in population estimates.
Terrestrial and freshwater invertebrates in the neuston of the Bay of Fundy, Canada
Authors: Locke A. , Corey S.
Published: August 2008

More than 106 families of insects representing 12 orders, spiders, mites, and millipedes were collected in the neuston of the Bay of Fundy in spring, summer, and autumn. Homoptera, Diptera, and Hymenoptera were dominant in number of families and (or) number of individuals. Seasonal and annual variations in taxonomic composition and in abundance were considerable. The abundant detritus of terrestrial and fluvial origin in the neuston, especially in summer, may be a potentially important food source for surface-feeding animals.
Genetic variation in all-or-none life-history traits of the lacewing Chrysoperla carnea
Authors: Tauber Catherine A. , Tauber Maurice J.
Published: August 2008

Aestival reproduction varies qualitatively within many western North American populations of the Chrysoperla carnea species complex; during the summer, individuals either reproduce or enter reproductive diapause. The expression of this all-or-none phenotypic trait is determined by two ecophysiological response patterns: response to photoperiod and response to prey. These response patterns also vary qualitatively. Artificial selection on the reproductive phenotype significantly altered both the pattern of reproduction and the ecophysiological responses that control reproduction. In populations from western North America, the propensity for aestival reproduction is polygenically inherited, and the trait has considerable genetic variability. This variation occurs in two forms: (i) some is expressed currently and is immediately subject to natural selection (actual variation), and (ii) some is expressed in later generations and therefore is subject to natural selection only after recombination (hidden variation). Both forms of variation are important in the evolution of polymorphic seasonal cycles and seasonally diversified geographical populations.