Reduced fecundity of Psoroptes ovis (Hering) (Acari: Psoroptidae) on calves treated with ivermectin

1984 ◽  
Vol 74 (4) ◽  
pp. 657-662 ◽  
Author(s):  
Frank S. Guillot ◽  
Fred C. Wright

AbstractIvermectin injected subcutaneously into calves at the rate of 200 μ/kg body weight completely eliminated females of Psoroptes ovis (Her.) in 22 days. Injection of ivermectin also adversely affected the number and hatch of eggs and the proportion of adult males forming attachment pairs. The reduced number of eggs recovered in skin scrapings was apparently the result of a significantly lower fecundity among females that temporarily survived on treated calves. Females that were exposed to ivermectin for only three days did not recover their full reproductive potential even though they were transferred to calves not injected with ivermectin. The proportion of ovigerous females among survivors was not significantly affected five days after injection. Since the number of eggs recovered in skin scrapings was substantially reduced after only three days, the effect of ivermectin on female fecundity was not primarily gonadal. Reduction in the number of P. ovis eggs three days after treatment probably occurred because of a combination of mortality of adult females and reduced oviposition by ovigerous females surviving in the population.

1958 ◽  
Vol 4 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Mary L. Petermann ◽  
Mary G. Hamilton

Rat liver was homogenized in 0.88 M sucrose. The DNA and total RNA were determined, and the homogenate was fractionated by differential centrifugation. The pellets obtained between 30 minutes at 20,000 g and 180 minutes at 105,000 g were analyzed for RNA and nitrogen. The ribonucleoproteins were determined in the analytical ultracentrifuge. The non-pellet RNA was calculated by difference. The results are reported as amounts per 6.7 x 10-9 mg. of DNA. In young, growing male rats the amounts of microsomal protein and ribonucleoprotein B (83S) increased with age. Non-pregnant adult females showed less non-pellet RNA and much more ribonucleoprotein C (63S) than did adult males. During pregnancy both of these cell constituents reverted to levels characteristic for male animals. Starvation for 5 days resulted in a reduction in the mass of liver tissue, the non-pellet RNA, the microsomal protein, and ribonucleoproteins B and C. During recovery from starvation the return of the liver to normal paralleled the rate at which body weight was restored. Treatment with cortisone, 25 mg. per rat per day for 5 days, caused an increase in microsomal protein and a decrease in ribonucleoprotein B. Treatment with 6-mercapto-purine, 50 mg. per kilo per day for 5 days, caused little change in liver composition in either males or females.


1993 ◽  
Vol 20 (3) ◽  
pp. 287 ◽  
Author(s):  
TR Soderquist ◽  
M Serena

A laboratory assessment of the susceptibility of Dasyurus geoffroii to baits used to control foxes and dingoes was conducted using five types of non-poisoned baits: polony, fresh meat, meat dried by 50% and 70% of the original weight, and compressed beef crackle. Trials were designed to simulate the initial encounter of a bait by hungry wild juveniles and adults of both sexes, including lactating females. In overnight trials, juveniles and lactating females ate significantly more fresh meat per body weight (mean consumption: 23.7% for juvenile males, 21.5% for juvenile females, 23.1% for lactating females) than non-lactating adult females and adult males (combined mean, 18.3%). Maximum overnight bait consumption was 43% of body weight. These values greatly exceed those previously reported for other species of Dasyurus. Moist baits were eaten more rapidly and in larger amounts than drier baits. Seasonal factors lead to the prediction that the period when canid baiting can be conducted with the least danger to Dasyurus geoffroii is January-March.


2011 ◽  
Vol 56 (No. 4) ◽  
pp. 180-186 ◽  
Author(s):  
L. Ondruska ◽  
J. Rafay ◽  
AB Okab ◽  
MA Ayoub ◽  
AA Al-Haidary ◽  
...  

This study was conducted to investigate the effect of heat stress (i.e., elevated ambient temperature &ndash; Ta; 36 &deg;C &plusmn; 3 &deg;C) on growth performance, mortality rate, and on some haematological and biochemical parameters in different categories of gender and age of New Zealand White (NZW) rabbits. Animals were divided into two main groups (control and treatment), in each group there were 56 rabbits: adult females (n = 20), adult males (n = 4), growing females (n = 16), and growing males (n = 16). Results revealed that total and daily feed intake, feed conversion ratio, and total and daily gain in body weight for growing NZW rabbits were affected negatively by elevated Ta. Decreases in feed intake led to less protein biosyntheses and less fat deposition, which led to lower body weight gain. These observations were made in growing and adult rabbits of both genders. Analysis showed that red blood cell (RBC) counts showed alterations. Packed cell volume (PCV) (in adult females and males), white blood cell (WBC) counts (in growing females), lymphocytes (in growing males), monocytes (in growing females and adult males), basophils (in growing females and growing and adult males) were significantly (P &lt; 0.05) decreased, and total proteins (TP) (in adult females), glucose (Glu) (in adult females), and calcium (Ca<sup>2+</sup>) (in growing males and females) were significantly (P &lt; 0.01) lower in the experimental group. Furthermore, elevated Ta increased the mortality rate (MR) in both age groups. The mortality rate was 30.36% for growing and adult rabbits of the experimental group, compared with 7.14% for the control group, and was 25% for adult compared with 34.38% for growing experimental rabbits. Exposure of NZW rabbits of both ages and genders to elevated ambient temperature (36&deg;C &plusmn; 3 &deg;C), negatively affected their internal homeostasis which was reflected in their growth rate and various physiological signs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dominika Stygar ◽  
Tomasz Sawczyn ◽  
Agnieszka Dulska ◽  
Elżbieta Chełmecka ◽  
Łukasz Mielańczyk ◽  
...  

AbstractWe studied the long-term effect of ileal transposition (IT) metabolic surgery on the hepatokines: retinol-binding protein-4 (RBP4), α-2-HS-glycoprotein (aHSG/fetuin-A), and fibroblast growth factor 21 (FGF21), C-reactive protein (CRP) plasma levels, glucose metabolism, body weight, liver histology, as well as total lipids concentration in muscle, liver, and fat tissue of obese Zucker (Crl:ZUC(ORL)-Leprfa) rats. 14 adult males were randomly submitted either to IT or SHAM (control) surgery. Pre-operative hepatokines plasma levels were not significantly different in rats submitted to IT or SHAM protocol. Three months after the procedures the plasma levels of RBP4, aHSG, FGF21, and CRP were significantly lower in IT-operated animals when compared to SHAM-operated group. Three and 12 weeks after the IT and SHAM surgery, the AUCOGTT were significantly lower than AUCOGTT before the surgery. HOMA-IR was lower in rats after IT surgery in comparison to the SHAM-operated rats. Muscle and liver total lipids concentration was reduced after the IT procedure when compared to pre-IT conditions. IT had a significant reductive impact on the body weight in comparison to SHAM surgery in the 4th, 6th, 8th, and 10th week after the surgery. We conclude that IT reduces hepatokines’ plasma concentrations, muscle and liver total lipids concentration but not the inflammatory processes in the liver of Zucker (Crl:ZUC(ORL)-Leprfa) rats.


Zootaxa ◽  
2011 ◽  
Vol 2983 (1) ◽  
pp. 39 ◽  
Author(s):  
IVAN L. F. MAGALHÃES ◽  
ADALBERTO J. SANTOS

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.


1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero

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.


1951 ◽  
Vol 42 (2) ◽  
pp. 399-418 ◽  
Author(s):  
S. Pradhan ◽  
S. C. Bhatia

The relationship was studied between susceptibility of a number of different species of insects to HCN fumigation and the recovery of HCN from them immediately after fumigation.The test insects used were Tribolium castaneum, seventh stage caterpillars of Corcyra cephalonica, first-and second-instar nymphs of Drosicha sp., third-and fourthinstar nymphs of Drosicha sp. and adult females of Drosicha sp.The apparatus and methods used in the fumigation and in the recovery of HCN from the fumigated insects are fully described.Preliminary expsriments showed that the processes of distillation and redistillation did not affect the recovery of HCN but that the result obtained for recovery from distillation could be affected if some volatile reducing substance were produced and carried over to the distillate. It was found that this did actually take place in the case of one of the test insects—T. castaneum—but that redistillation got rid of the impurity.In the main experiments it was shown that, on the assumption that the concentration of HCN to which insects are exposed is the effective dosage, the susceptibility of the test insects varied in the following descending order : firstand second-stage nymphs of Drosicha sp. > third- and fourth-stage nymphs of Drosicha sp.>C. cephalonica> T. castaneum>the adult females of Drosicha sp.When the same insects were arranged in descending order of the quantities of HCN recovered per 100 gm. of body weight, the order was identical except for the nymphs of Drosicha sp. which occupied a different relative position. The two categories of nymphs of Drosicha sp. were found to occupy a different relative position again with regard to the other three test insects when exposed to a superlethal concentration and assessed for recovery of HCN per 100 gr. body weight.Parallel batches of T. castaneum and C. cephalonica were fumigated and the HCN was recovered from the dead and survivors. More HCN was recovered from the dead insects than from those that survived.Both recovery and sorption of HCN were estimated separately in parallel batches of insects (adult females of Drosicha sp. and C. cephalonica). Recovery was found to be less than sorption showing that a part of the HCN absorbed is converted into a non-recoverable state. Further, that the weight of HCN sorbed per gram body weight of adult females of Drosicha sp. is much less than in the case of C. cephalonica under similar conditions of fumigation and that the amount of HCN converted into non-recoverable products is less in Drosicha adults than in C. cephalonica.A comparison of the water content of T. castaneum, C. cephalonica and Drosicha sp. (adults) showed that there was a positive correlation between water content and higher susceptibility to HCN and greater recovery of HCN was also indicated. It is suggested that this may be a factor in the “ Surface Resistance ” of an insec to a fumigant.The observations of previous workers that larger amounts are sorbed by or recovered (after fumigation) from more susceptible species than for those less susceptible was corroborated by the results obtained with C. cephalonica, T. castaneum and adult females of Drosicha sp. but not with those from nymphs of Drosicha sp.When dosage-mortality graphs were prepared by taking the amount of HCN recovered per gram body weight as an index of internal dose, the order of resistance of different test insects based on this new criterion was found to be entirely different from that based on the usual criterion of the concentration of HCN in the fumatorium being the index of effective dosage.These apparently anomalous observations may be explained by assuming that the resistance shown by an insect in an actual fumigation operation, i.e., to the concentration of HCN to which it is exposed (external dose) is what may be called the total “ Effective Resistance ” and that this “ Effective Resistance ” is the resultant of (a) “ Surface Resistance ” to the entry of fumigant and (b) “ Internal Resistance ” to the amount of HCN which actually gains entry into the body in some way or other. Thus the “Effective Resistance ” of an insect may be due to a combination either of low “ Surface Resistance ” and high “ Internal Resistance ”, giving a very low “ Effective Resistance ” as in the case of C. cephalonica, or vice versa giving the maximum “ Effective Resistance ” as in adult females of Drosicha sp. The lower recovery of HCN from the nymphs of Drosicha sp., although they were more susceptible to fumigation than C. cephalonica, is explained by their higher “ Surface Resistance ” combined with a very much lower “ Internal Resistance ”, leading to a lower “ Effective Resistance ”.


Behaviour ◽  
1980 ◽  
Vol 72 (1-2) ◽  
pp. 26-48 ◽  
Author(s):  
Patrick Duncan

AbstractTime-budgets of adult and weaned sub-adult horses were studied in a small population of Camargue horses living in semi-liberty. The categories of activities used were: Standing resting, Lying flat, Lying up, Standing alert, Walking, Trotting, Galloping, Rolling and Foraging. The main differences in time-budgets were related to age and to sex : young horses spent more time lying (sleeping), males spent more time standing alert and in rapid movements (trot, gallop), while usually foraging less than did the adult females. During the three years of the study the population increased from 20 to 54 horses and there were considerable changes in social structure as the number of adult males increased. Associated with these developments there were some changes between years in the time-budgets: the most striking of which was a general trend for all horses to spend less time lying. Nonetheless the time-budgets showed a considerable constancy across years and age/sex-classes, especially with regard to time spent foraging. This conclusion may provide a clue as to why horses have an unusual social system based on long term relationships between a male and the females of his harem.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Paul J. Ode ◽  
Dhaval K. Vyas ◽  
Jeffrey A. Harvey

The diverse ecology of parasitoids is shaped by extrinsic competition, i.e., exploitative or interference competition among adult females and males for hosts and mates. Adult females use an array of morphological, chemical, and behavioral mechanisms to engage in competition that may be either intra- or interspecific. Weaker competitors are often excluded or, if they persist, use alternate host habitats, host developmental stages, or host species. Competition among adult males for mates is almost exclusively intraspecific and involves visual displays, chemical signals, and even physical combat. Extrinsic competition influences community structure through its role in competitive displacement and apparent competition. Finally, anthropogenic changes such as habitat loss and fragmentation, invasive species, pollutants, and climate change result in phenological mismatches and range expansions within host–parasitoid communities with consequent changes to the strength of competitive interactions. Such changes have important ramifications not only for the success of managed agroecosystems, but also for natural ecosystem functioning. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.


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