Epizootiology of the reindeer nose bot fly, Cephenemyia trompe (Modeer) (Diptera: Oestridae), in reindeer, Rangifer tarandus (L.), in Norway

1995 ◽  
Vol 73 (6) ◽  
pp. 1024-1036 ◽  
Author(s):  
Arne C. Nilssen ◽  
Rolf E. Haugerud
Keyword(s):  
Rangifer Tarandus ◽  
Negative Binomial ◽  
First Instar ◽  
High Infection ◽  
Bot Fly ◽  
Two Measures ◽  
Southern Norway ◽  
Major Factors ◽  
Cephenemyia Trompe ◽  
Host Behaviour

First-instar larvae of the reindeer nose bot fly, Cephenemyia trompe (Modeer) (Diptera: Oestridae), were sampled with a rinsing and sieving technique from 571 semidomesticated reindeer, Rangifer tarandus (L.), from different districts in northern Norway in the infection years 1983, 1984, 1985, 1987, and 1988, and from 44 wild reindeer from southern Norway (infection year 1983). This is the first comprehensive epizootiological study of this parasite from Fennoscandia. The first instar was found between 10 September to 25 May, the second instar from 11 February to 17 May, and the third instar from 3 April to 28 June. Old third-instar larvae were sometimes found trapped in the sinuses of the host. The overall prevalence of infection was 65.2% (range 6.7 – 100%) and the abundance (= relative density) was 11.53 (range 6.7 – 62.7). Individual intensities ranged from 0 to 221. There were significant differences in abundance between some districts and years. Distance and timing of the spring migration of the host are thought to be the major factors causing variability in infection levels between districts, whereas the summer climate during infection greatly influenced the differences between years. The frequency distribution was highly overdispersed (aggregated) and could adequately be described by the negative binomial model (overall parameter, k = 0.29, range 0.03 – 2.64). Heterogeneity in host behaviour during infestation is hypothesized to create this parasite distribution. Two measures of aggregation, Morisita's index of aggregation (IM) and1/k, decreased with larval burden, indicating that factors restricting parasite numbers (negative feedback) start to operate at high infection levels.

scholarly journals The timing and departure rate of larvae of the warble fly Hypoderma (= Oedemagena) tarandi (L.) and the nose bot fly Cephenemyia trompe (Modeer) (Diptera: Oestridae) from reindeer

Rangifer ◽  
1994 ◽  
Vol 14 (3) ◽  
pp. 113 ◽  
Author(s):  
Arne C. Nilssen ◽  
Rolf E. Haugerud
Keyword(s):  
Biological Control ◽  
Temporal Pattern ◽  
Rangifer Tarandus ◽  
Spring Migration ◽  
Slight Effect ◽  
Rangifer Tarandus Tarandus ◽  
Departure Time ◽  
Bot Fly ◽  
Cephenemyia Trompe

The emergence of larvae of the reindeer warble fly Hypoderma (= Oedemagena) tarandi (L.) (n = 2205) from 4, 9, 3, 6 and 5 Norwegian semi-domestic reindeer yearlings (Rangifer tarandus tarandus (L.)) was registered in 1988, 1989, 1990, 1991 and 1992, respectively. Larvae of the reindeer nose bot fly Cephenemyia trompe (Moder) (n = 261) were recorded during the years 1990, 1991 and 1992 from the same reindeer. A collection cape technique (only H. tarandi) and a grating technique (both species) were used. In both species, dropping started around 20 Apr and ended 20 June. Peak emergence occurred from 10 May - 10 June, and was usually bimodal. The temperature during the larvae departure period had a slight effect (significant only in 1991) on the dropping rate of H. tarandi larvae, and temperature during infection in the preceding summer is therefore supposed to explain the uneven dropping rate. This appeared to be due to the occurrence of successive periods of infection caused by separate periods of weather that were favourable for mass attacks by the flies. As a result, the temporal pattern of maturation of larvae was divided into distinct pulses. Departure time of the larvae in relation to spring migration of the reindeer influences infection levels. Applied possibilities for biological control by separating the reindeer from the dropping sites are discussed.

scholarly journals The method by which Cephenemyia trompe (Modeer) larvae invade reindeer (Rangifer tarandus)

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 291 ◽  
Author(s):  
John R. Anderson ◽  
Arne C. Nilssen
Keyword(s):  
Experimental Evidence ◽  
Rangifer Tarandus ◽  
Physiological Saline ◽  
First Instar ◽  
Cephenemyia Trompe

Laboratory electrostimulated C. trompe (Modeer) females forcefully expelled (sprayed) larvae for 5-20 cm. The watery spray consisted of about 20 tiny droplets containing two to several larvae. Crawling first-instar larvae exhibited negative geotactic and phototropic responses; they were subject to rapid desiccation and became immobile as the tiny droplets dried within a few seconds. When 5-50 larvae from dissectedfemales were dropped in physiological saline onto different areas of the muzzle of restrained reindeer, only larvae placed deep within the nostrils and on the lips crawled out-of-sight down the nostril passage or into the mouth. Drops of larvae placed elsewhere quickly desiccated and the larvae became immobile. Larvae deposited by wild females onto a COz-baited reindeer model with the muzzle, lips and nostrils coated with insect trapping adhesive all were stuck only along the dorsal lip below the philtrum. All experimental evidence supports a natural per os mode of invasion.

scholarly journals The mating sites of the reindeer nose bot fly: not a practical target for control

Rangifer ◽  
1995 ◽  
Vol 15 (2) ◽  
pp. 55 ◽  
Author(s):  
Arne C. Nilssen ◽  
John R. Anderson
Keyword(s):  
Rangifer Tarandus ◽  
Target Species ◽  
Northern Norway ◽  
Bot Fly ◽  
Grazing Area ◽  
Cephenemyia Trompe ◽  
Number Of Males ◽  
Summer Grazing

The reindeer nose bot fly Cephenemyia trompe aggregates on hilltops/mountaintops to mate. Although active only for brief periods on certain days, males have been collected only from such sites. To evaluate possible suppression of the fly population by killing males (by insecticides or traps) at such sites, the density of sites and the number of males at each site were monitored in a summer grazing area of the semidomestic reindeer host (Rangifer tarandus) in Finnmark, northern Norway. In an area of ca. 20 km2, 19 mating sites were detected and examined during 4 hours on one day. The number of males observed at most sites was 5-16 (range 3-60). Minor hilltops had few males but at some sites >20-60 flies were dispersed over an area of at least 100 m2. It is concluded that mating sites in the study area are too numerous, and also used by many beneficial non-target species, to be practical targets for control of the species.

scholarly journals Development of models to study traffic accidents on the final sections of access roads to the cities: a case study of three major Iranian cities

2021 ◽  
Vol 59 (3) ◽  
pp. 129-148
Author(s):  
Mehdi Fallah Tafti ◽  
Reza Roshani
Keyword(s):  
Traffic Accidents ◽  
Probabilistic Models ◽  
Negative Binomial ◽  
Ann Model ◽  
Lighting Condition ◽  
Traffic Characteristics ◽  
Ann Models ◽  
Accident Rates ◽  
Roadway Lighting ◽  
Major Factors

The final sections of main access roads to the cities require especial attention as the frequency of accidents in these road sections are considerably higher than other parts of interurban roads. These road sections operate as an interface between the rural roads and urban streets. The previous researches available on this subject are limited and they have also mainly focused on a narrow range of factors contributing to the accidents in these areas. The main contribution of this research is to consider a relatively comprehensive range of potential factors , and to examine their impacts through the development and comparison of both conventional probabilistic models and Artificial Neural Network (ANN) models. For this purpose, information related to the main access roads of three major Iranian cities were collected. This information consisted of accident frequency data together with the field observations of traffic characteristics, road-way conditions and roadside features of these roads. Various ANN and probabilistic models were developed. The frequency of accidents, i.e. fatal, injured, or damaged accidents, was considered as the output of the developed models. The results indicated that a hybrid of ANN models, each comprised of 10 input variables representing traffic, roadway and roadside conditions, outperformed several probabilistic models, i.e. Poisson, Negative binomial, Zero-truncated Poisson, and Zero-truncated Negative Binomial models, also developed under similar conditions in this study. Moreo-ver, effective roadway width, roadway lighting condition, the standard deviation of vehicles speed, percentage of drivers violating the speed limit, average annual daily traffic, percentage of heavy goods vehicles, the density of road-side commercial and industrial landuses, the density of median U-turns, the density of local access roads, and the effective width of the left-side shoulder were identified as the most effective factors contributing to the accidents in these areas. The developed ANN model can be used as a tool to predict accident rates in these road sections, and to estimate a potential reduction in the accident rates, following any improvements in the major factors contributing to the traffic accidents in these areas.

Experimental Ascaris suum infection in the pig: worm population kinetics following single inoculations with three doses of infective eggs

Parasitology ◽  
1997 ◽  
Vol 115 (4) ◽  
pp. 443-452 ◽  
Author(s):  
A. ROEPSTORFF ◽  
L. ERIKSEN ◽  
H.-C. SLOTVED ◽  
P. NANSEN
Keyword(s):  
Negative Binomial ◽  
Transmission Rate ◽  
Ascaris Suum ◽  
Tissue Type ◽  
Post Inoculation ◽  
Experimental Conditions ◽  
Population Kinetics ◽  
White Spots ◽  
Host Status ◽  
Host Behaviour

To study population kinetics during primary Ascaris suum infections, 3 groups of 52 pigs each were inoculated with 100, 1000, or 10000 infective eggs. In all groups, the majority of larvae was found in the liver on day 3 post inoculation (p.i.) and in the lungs on day 7 p.i. Liver white spots, caused by migrating larvae, were most numerous at day 7 p.i., whereafter they gradually healed, and only low numbers of granulation-tissue type white spots and lymphonodular white spots persisted at days 21–56 p.i. Independent of dose level, 47–58% of the inoculated eggs were recovered as larvae in the small intestine on day 10 p.i., but most larvae were eliminated at days 17–21 p.i. This elimination started earlier and removed a higher percentage of the worms with increasing inoculation dose, resulting in small strongly aggregated worm populations by day 28 p.i. (k of the negative binomial distribution was low: 0·2–0·4) without significant differences between groups. Thus, overdispersion, which is a characteristic of both porcine and human ascarosis, is found here under experimental conditions where aggregation factors like host behaviour, transmission rate, host status etc have been partly or totally controlled.

Vigilance and fright behaviour in the insular Svalbard reindeer (Rangifer tarandus platyrhynchus)

2011 ◽  
Vol 89 (8) ◽  
pp. 753-764 ◽  
Author(s):  
Eigil Reimers ◽  
Steinar Lund ◽  
Torbjørn Ergon
Keyword(s):  
Human Activities ◽  
Rangifer Tarandus ◽  
Lower Probability ◽  
Supporting Evidence ◽  
Svalbard Archipelago ◽  
Svalbard Reindeer ◽  
Vigilance Behaviour ◽  
Southern Norway ◽  
Wild Reindeer ◽  
Flight Initiation

The insular Svalbard reindeer ( Rangifer tarandus platyrhynchus Vrolik, 1829) provide an opportunity to study vigilance behaviour in the absence of predators and parasitizing insects. We measured vigilance and fright and flight response during summer 2006 in the Svalbard archipelago; in four areas on Nordenskiöld Land on the island Spitzbergen and in one area on the island Edgeøya. Vigilance was higher in reindeer on Edgeøya than in the four Spitzbergen areas. Males were less vigilant than lactating and barren females and vigilance decreased with increasing group size. The relaxed vigilance behaviour in Svalbard reindeer compared with wild reindeer in southern Norway demonstrates a vigilance threshold in the absence of traditional predators of Rangifer Hamilton Smith, 1827. Alert, flight initiation, and escape distances were all shorter in Adventdalen, with Longyearbyen and its considerably higher amounts of human activities and infrastructure than in the other study areas, supporting evidence of habituation towards humans. There were no systematic vigilance or differences in fright and flight responses between reindeer in Colesdalen, Reindalen, and Sassendalen, indicating that a combination of low level of human activities including hunting, recreation, and scientific activities affected the animals differently. Lower probability of assessing before fleeing in Edgeøya (63% vs. 94% in the Nordenskiöld Land areas), along with their higher vigilance, may indicate more frequent interactions with polar bears ( Ursus maritimus Phipps, 1774) in Edgeøya.

scholarly journals Density or Connectivity: What Are the Main Causes of the Spatial Proliferation of COVID-19 in Korea?

2021 ◽  
Vol 18 (10) ◽  
pp. 5084
Author(s):  
Yun Jo ◽  
Andy Hong ◽  
Hyungun Sung
Keyword(s):  
Negative Binomial ◽  
Urban Environments ◽  
Regional Government ◽  
Urban Spatial Structure ◽  
Urban Centers ◽  
Urban Density ◽  
Two Measures ◽  
Government Websites ◽  
Binomial Models

COVID-19 has sparked a debate on the vulnerability of densely populated cities. Some studies argue that high-density urban centers are more vulnerable to infectious diseases due to a higher chance of infection in crowded urban environments. Other studies, however, argue that connectivity rather than population density plays a more significant role in the spread of COVID-19. While several studies have examined the role of urban density and connectivity in Europe and the U.S., few studies have been conducted in Asian countries. This study aims to investigate the role of urban spatial structure on COVID-19 by comparing different measures of urban density and connectivity during the first eight months of the outbreak in Korea. Two measures of density were derived from the Korean census, and four measures of connectivity were computed using social network analysis of the Origin-Destination data from the 2020 Korea Transport Database. We fitted both OLS and negative binomial models to the number of confirmed COVID-19 patients and its infection rates at the county level, collected individually from regional government websites in Korea. Results show that both density and connectivity play an important role in the proliferation of the COVID-19 outbreak in Korea. However, we found that the connectivity measure, particularly a measure of network centrality, was a better indicator of COVID-19 proliferation than the density measures. Our findings imply that policies that take into account different types of connectivity between cities might be necessary to contain the outbreak in the early phase.

scholarly journals Vigilance in reindeer (Rangifer tarandus); evolutionary history, predation and human interference

Polar Biology ◽  
2021 ◽  
Author(s):  
Eigil Reimers ◽  
Sindre Eftestøl ◽  
Jonathan E. Colman
Keyword(s):  
Genetic Variability ◽  
Evolutionary History ◽  
Rangifer Tarandus ◽  
Behavioral Responses ◽  
Low Density ◽  
Anatomy And Physiology ◽  
Vigilance Behaviour ◽  
Key Drivers ◽  
Southern Norway ◽  
Warning Time

AbstractTo elucidate genetic variability in vigilance behaviour for reindeer with historical differences in their interactions with predators and humans, we measured vigilance frequency and duration for grazing reindeer in Southern Norway (Rondane and Norefjell-Reinsjøfjell), Svalbard (Edgeøya and Nordenskiöld Land) and Barf/Royal Bay and Busen in the southern Hemisphere (South Georgia). Averaged for all areas, frequency and duration of vigilance bouts were less than 0.5 and 2.5 s, respectively. Frequency was insignificantly 1.3 times higher in Rondane than Edgeøya, and significantly 2.0, 3.5, 5.2 and 12.4 times higher than Norefjell, Nordenskiöld Land, Barf/Royal Bay and Busen, respectively. Duration per vigilance bout was not different amongst the areas. Thus, while frequency varied considerably, duration remained constant, supporting a hard-wired adaptation to, among other suggestions, an open landscape. Plasticity in frequency allows for flexible behavioral responses to environmental factors with predation, domestication and hunting key drivers for reindeer. Other factors include (1) the open, treeless alpine/Arctic environment inhabited by Rangifer subspecies allowing warning time, (2) grouping behaviour, (3) relative low density of predators and (4) the anatomy and physiology of ungulate vision.

Distribution and specificity of Mermithidae (Nematoda) infecting Simuliidae (Diptera) in Newfoundland

1980 ◽  
Vol 58 (8) ◽  
pp. 1483-1490 ◽  
Author(s):  
M. H. Colbo ◽  
G. N. Porter
Keyword(s):  
Life History ◽  
Final Host ◽  
Extensive Study ◽  
Host Distribution ◽  
Infection Pattern ◽  
Life History Pattern ◽  
Host Instar ◽  
High Infection ◽  
Late Instar ◽  
Host Behaviour

A number of simuliid populations infected with mermithids were studied to elucidate the nematode's life history patterns and the effect of this on the infected host's distribution. Some of the mermithids were very host specific, while others infected all simuliid species exposed to some degree. An extensive study showed that mermithids infecting Prosimulium mixtum failed to infect Stegopterna mutata which may have been due to the preparasites inability to recognize St. mutata as a potential host, or due to host behaviour, rather than microdistribution or physiology.In mermithid species where the majority complete their parasitic phase and emerge from the larval simuliid, the heaviest infections occur towards the downstream end of the host distribution. On the other hand those mermithid species which emerge only from adult simuliids have a high infection rate in the larval simuliids at the upstream end of host distribution. Infection occurs in the early simuliid instars, primarily first and second, with perhaps some in the older larvae. The rate of infection and the number of larvae per host changed between the time of simuliid hatch and the final host instar at most sites. However, the infection pattern in late instar larvae in any one stream appeared to be relatively stable from year to year.In the present study all mermithid infections of adult hosts were confined to the female fly irrespective of the mermithids life history pattern.

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