Larval development of the parasitic copepod Salmincola edwardsii on brook trout (Salvelinus fontinalis)

1994 ◽  
Vol 72 (1) ◽  
pp. 154-159 ◽  
Author(s):  
David C. Conley ◽  
Mark A. Curtis
Keyword(s):  
Larval Development ◽  
Brook Trout ◽  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Infection Intensity ◽  
Parasitic Copepod ◽  
Developmental Time ◽  
Adult Males ◽  
Pectoral Fins ◽  
Adult Females

We conducted laboratory experiments to determine the developmental time from larva to adult of the parasitic copepod Salmincola edwardsii on brook trout (Salvelinus fontinalis) at 13 °C. Healthy fingerlings were exposed to large doses of recently hatched copepodids for 12 h. Three infected fingerlings were sacrificed at 12-h intervals until day 6 and then at 24-h intervals until day 20 postexposure. The gills, opercula, and pectoral fins were the major sites of attachment. Adult males were detected as early as day 3 and as late as day 8 postexposure, with the greatest number occurring about day 5. Adult males may live for up to 3 days at 13 °C. Adult females were detected as early as day 11 postexposure but not consistently until day 13, indicating that permanent bulla attachment took place between 11 and 16 days postexposure. Infection intensity declined rapidly until day 9 postexposure then less quickly for the rest of the experiment.

Effects of temperature fluctuations and photoperiod on hatching in the parasitic copepod Salmincola edwardsii

1990 ◽  
Vol 68 (6) ◽  
pp. 1330-1332 ◽  
Author(s):  
Robert Poulin ◽  
David C. Conley ◽  
Mark A. Curtis
Keyword(s):  
Brook Trout ◽  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Temperature Fluctuations ◽  
Parasitic Copepod ◽  
The Other ◽  
Hatching Rate ◽  
Experimental Conditions ◽  
Effects Of Temperature ◽  
Daily Changes

In laboratory experiments, we studied the effects of the day–night cycle (photoperiod and temperature fluctuations) on the initiation of hatching and hatching rate in egg sacs of the copepod Salmincola edwardsii, ectoparasitic on brook trout (Salvelinus fontinalis). Pairs of egg sacs were removed from adult female copepods; for each pair, one sac was placed under experimental conditions and the other one was kept under constant conditions, providing an ideal control. Photoperiod had no significant effect on the initiation of hatching or hatching rate. The observed effects of temperature fluctuations were associated with water temperature itself, and appeared independent of whether it was fluctuating or constant. We conclude that hatching in S. edwardsii is not rhythmical but spontaneous, showing no relationship with daily changes in host vulnerability.

Effects of temperature and photoperiod on the duration of hatching, swimming, and copepodid survival of the parasitic copepod Salmincola edwardsii

1993 ◽  
Vol 71 (5) ◽  
pp. 972-976 ◽  
Author(s):  
David C. Conley ◽  
Mark A. Curtis
Keyword(s):  
Water Temperature ◽  
Brook Trout ◽  
Laboratory Experiments ◽  
Hatching Success ◽  
Salvelinus Fontinalis ◽  
Parasitic Copepod ◽  
Swimming Activity ◽  
The Other ◽  
Egg Hatching ◽  
Effects Of Temperature

We conducted laboratory experiments to test whether various temperature and photoperiod regimes had any effect on the duration of egg hatching, swimming activity, and copepodid survival in the parasitic copepod Salmincola edwardsii, commonly found on brook trout (Salvelinus fontinalis). Pairs of egg sacs were removed from adult female copepods; one of each pair was exposed to a different photoperiod than the other, at the same temperature. Experiments were conducted at 8, 12, 16, and 20 °C. Temperature had a significant effect on the duration of copepodid swimming activity and survival, and the onset of egg sac hatching was directly related to increasing water temperature. However, hatching duration and hatching success were not affected by temperature over the range tested. Photoperiod had no effect on hatching duration, hatching success, swimming activity, or copepodid survival. Our findings indicate that S. edwardsii copepodids can swim and survive for more than 2 weeks; much longer than the 2 days customarily reported in the literature. This must be accounted for in the development of strategies to control transmission.

Abundance and Potential Pathology of Parasites Infecting Salmonids in Canadian Maritime Hatcheries

1974 ◽  
Vol 31 (6) ◽  
pp. 1031-1036 ◽  
Author(s):  
G. M. Hare ◽  
C. Frantsi
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brook Trout ◽  
Parasite Species ◽  
Salvelinus Fontinalis ◽  
Infection Intensity ◽  
Salmo Gairdneri ◽  
Host Age ◽  
Intensity Of Infection ◽  
First Time

Seventeen parasite species (3 protozoans, 11 helminths, 2 arthropods, and 1 mollusc) were collected from 317 Atlantic salmon (Salmo salar), 207 brook trout (Salvelinus fontinalis), and 34 rainbow trout (Salmo gairdneri) in the 13 Canadian Maritime hatcheries during 1972. Four parasites, Camallanus oxycephalus, Pomphorhynchus bulbocolli, Hydrachna sp., and a glochidium, were recorded from Atlantic salmon for the first time. Incidence and intensity of infection were high for Trichophyra piscium, Diplostomulum spathaceum, and glochidia infecting salmon and for Acanthocephalus lateralis and Salmincola edwardsii infecting brook trout. Infection intensity of Apophallus imperator, D. spathaceum, S. edwardsii, and glochidia increased with host age. Apophallus imperator and S. edwardsii were host specific to brook trout and the glochidium was host specific to salmon. Sterliadochona tenuissima and A. lateralis were more abundant in brook trout than in salmon. Pathology was associated with infections of Hexamita salmonis, D. spathaceum, A. lateralis, and S. edwardsii.

Responses of the fish ectoparasite Salmincola edwardsii (Copepoda) to stimulation, and their implication for host-finding

Parasitology ◽  
1990 ◽  
Vol 100 (3) ◽  
pp. 417-421 ◽  
Author(s):  
R. Poulin ◽  
M. A. Curtis ◽  
M. E. Rau
Keyword(s):  
Shock Waves ◽  
Mechanical Stimulation ◽  
Strong Evidence ◽  
Brook Trout ◽  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Selective Pressure ◽  
Host Finding ◽  
And Shock Waves ◽  
Energy Stores

SUMMARYThe short-lived infective copepodid stages of the copepod Salmincola edwardsii, ectoparasitic on brook trout, Salvelinus fontinalis, are under strong selective pressure to evolve efficient host-finding mechanisms. In laboratory experiments, we quantified the effects of visual and mechanical stimulation on the activity of the copepodids. We found that shadows passing above the copepodids and shock waves passing through the water generated marked increases in the rate and length of upward swimming bursts, which resulted in more time spent suspended in the water column and greater distances travelled. However, we found no strong evidence for a relationship between the magnitude of the copepodids' response and the intensity of stimulation. Although these responses are not host-specific, they allow the parasites to conserve their limited energy stores by increasing their host-finding activity only when potential hosts are nearby.

Threat-sensitive predator avoidance by slimy sculpins: understanding the importance of visual versus chemical information

2001 ◽  
Vol 79 (5) ◽  
pp. 867-873 ◽  
Author(s):  
Douglas P Chivers ◽  
Reehan S Mirza ◽  
Pamela J Bryer ◽  
Joseph M Kiesecker
Keyword(s):  
Field Experiment ◽  
Brook Trout ◽  
Predator Avoidance ◽  
Visual Cues ◽  
Laboratory Experiments ◽  
Chemical Cues ◽  
Salvelinus Fontinalis ◽  
Chemical Information ◽  
Cottus Cognatus ◽  
Predation Threat

The supposition that prey animals assess and behave flexibly in response to different degrees of predation threat is known as the threat-sensitive predator avoidance hypothesis. We completed a series of field and laboratory experiments to examine whether slimy sculpins (Cottus cognatus) exhibit threat-sensitive predator avoidance when exposed to sympatric predatory brook trout (Salvelinus fontinalis). In a field experiment we caged small and large trout in similar habitats and found that sculpins avoided areas containing trout that were large enough to pose a threat to them, but did not avoid areas containing trout that were small and hence not a threat. In a series of laboratory experiments we found that sculpins showed threat-sensitive predator avoidance when they could assess the predator visually. However, when only chemical cues from the predator were presented, sculpins responded to the predator regardless of its size. Chemical cues seem to function to warn the sculpin that the predator is in the vicinity, but visual cues are needed in order to accurately assess the risk posed by the predator.

Some Factors Regulating Piscivory of Brook Trout, Salvelinus fontinalis, in Lakes of the Laurentian Shield

1991 ◽  
Vol 48 (9) ◽  
pp. 1735-1743 ◽  
Author(s):  
Pierre East ◽  
Pierre Magnan
Keyword(s):  
Brook Trout ◽  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
The Other ◽  
Prey Fish ◽  
Significant Preference ◽  
Prey Refuge ◽  
Semotilus Atromaculatus ◽  
Foraging Pattern ◽  
Creek Chub

A survey of 13 lakes containing brook trout, Salvelinus fontinalis, and northern redbelly dace, Phoxinus eos, five lakes containing trout and creek chub, Semotilus atromaculatus, and six lakes containing trout, dace, and chub indicated that prey-fish could represent up to 30% of trout diet by weight. We observed that trout preyed almost exclusively on dace, predation increased with trout size, predation on dace was significantly higher in the Salvelinus-Phoxinus-Semotilus association than in the Salvelinus-Phoxinus association even though trout were significantly smaller in the former than in the latter association, and predation in the Salvelinus-Phoxinus-Semotilus association was higher in two lakes and nearly always absent in the other four. Laboratory experiments indicated that small trout (150–250 mm total length (TL)) preferred small prey-fish (40–60 mm TL), large trout (250–380 mm TL) showed no significant preference with regard to the size of prey-fish (up to 170 mm TL), trout of both size classes preferred dace when dace and chub were present, presence of refuge (Cassandra calyculata) for prey-fish significantly reduced the number of attacks and captures upon dace, and large trout switched from an active to a sit-and-wait foraging pattern when a prey refuge was present.

Male Mate Choice in a Natural Population of the Parasitic Copepod Lernaeocera Branchialis (Copepoda: Pennellidae)

Behaviour ◽  
1996 ◽  
Vol 133 (3-4) ◽  
pp. 221-239 ◽  
Author(s):  
Thomas A. Schram ◽  
Peter Andreas Heuch
Keyword(s):  
Mate Choice ◽  
Natural Population ◽  
Sex Ratios ◽  
Mate Guarding ◽  
Parasitic Copepod ◽  
Male Mate Choice ◽  
Adult Males ◽  
Larval Stages ◽  
Adult Females ◽  
Male Mate

AbstractVariations in age and sex structure of a natural population of the copepod Lernaeocera branchialis, parasitic on flounder, Platichthys flesus were examined in a 15-month study. Recent laboratory studies and literature on reproductive strategies indicate that male mate choice in this species should depend on the sex ratios of the parasite on its hosts, and on the age and mating status of females. Sex ratios suggested a strong intra-male competition for females. The ratio of chalimus 4 and virgin adult females (preferred stages) to adult males exceeded 1 female: 4 males on 50% of the hosts. In four out of the six sampling periods, more than 50% of hosts harboured more adult males than the total number of females. The males preference for the different female stages was estimated from the number of precopula and copula associations. The data were fitted to a logistic regression model. At most sex ratios, males preferred chalimus 4 and virgin adult females, and discriminated against younger stages. Mated females were about as attractive as the youngest larval stages at female-biased sex ratios, but they were chosen more frequently at strongly male-biased sex ratios. Most adult L. branchialis females had copulated more than once, and some had accommodated at least 5 ejaculates in the their sperm storage organs. The patterns of mate guarding and potential for sperm competition strongly suggest that L. branchialis males take the intrasexual competition into account when choosing mates. On this basis, they minimize guarding time and maximize the possibility of paternity.

scholarly journals Variability in weed biological control : effects of foliar nitrogen on larval development and dispersal of the alligatorweed flea beetle, Agasicles hygrophila

2021 ◽  
Author(s):  
Harms Nathan ◽  
Cronin James
Keyword(s):  
Biological Control ◽  
Larval Development ◽  
Laboratory Experiments ◽  
Biological Control Agent ◽  
Flea Beetle ◽  
Field Measurements ◽  
Developmental Time ◽  
Control Agent ◽  
Weed Biological Control ◽  
Foliar Nitrogen

Host quality can have dramatic effects on performance of biological control agents but its importance is understudied. We used a combination of field measurements and laboratory experiments to determine the range of foliar nitrogen (FN) that larvae of the alligatorweed flea beetle (Agasicles hygrophila) are exposed to in the field and its importance to larval development and dispersal. Seasonal variability in FN was assessed at field sites spanning southern to northern Louisiana every 2–3 weeks during the growing season for four years. In a series of laboratory experiments, alligatorweed FN was manipulated to examine its influence on larval development and survival (under different temperature regimes), adult biomass, and dispersal of the biological control agent, A. hygrophila. Foliar nitrogen and rearing temperature had strong independent effects on larval development rate. We demonstrated that increasing nitrogen in leaf tissues shortens larval A. hygrophila developmental time and increases survival to adulthood, regardless of exposure temperature during development. It also suggests that foliar nitrogen may have important effects on biological control of alligatorweed, particularly as a result of seasonal variation in temperature and plant nutrition at field sites and could contribute to observed variation in A. hygrophila efficacy in the field.

Two new species and taxonomic notes on the Neotropical spiny orb-weaving spi-ders Micrathena and Chaetacis (Araneae: Araneidae), with remarks on the development of Micrathena excavata IVAN L. F. MAGALHÃES & ADALBERTO J. SANTOS (Brazil)

Zootaxa ◽  
2011 ◽  
Vol 2983 (1) ◽  
pp. 39 ◽  
Author(s):  
IVAN L. F. MAGALHÃES ◽  
ADALBERTO J. SANTOS
Keyword(s):  
New Species ◽  
Junior Synonym ◽  
Adult Males ◽  
Development Stages ◽  
Brazilian Amazonia ◽  
Central Brazil ◽  
Adult Females ◽  
Two New Species ◽  
Senior Synonym ◽  
First Time

In this paper, M. yanomami n. sp., from Brazilian Amazonia, Chaetacis bandeirante n. sp., from Central Brazil, and the males of M. gaujoni Simon, 1897 and M. ruschii (Mello-Leitão, 1945) n. comb. , respectively from Ecuador and Brazil, are described and illustrated for the first time. An ontogenetic series of the last development stages of both sexes of Micrathena excavata (C. L. Koch, 1836) is illustrated and briefly described. Adult females are larger and have longer legs and larger abdomens than adult males. Probably females undergo at least one additional moult before adulthood, compared to males. Micrathena ornata Mello-Leitão, 1932 is considered a junior synonym of M. plana (C. L. Koch, 1836), and M. mastonota Mello-Leitão 1940 is synonymized with M. horrida (Taczanowski, 1873). Acrosoma ruschii Mello-Leitão, 1945 is revalidated, transferred to Micrathena and considered a senior synonym of M. cicuta Gonzaga & Santos, 2004. Chaetacis necopinata (Chickering, 1960) is recorded for Brazil for the first time. Chaetacis incisa (Walckenaer, 1841) is considered a nomen dubium.

Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

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