Ecology of the cattle tick (Boophilus microplus) in subtropical Australia. I. Introduction and free-living stages

1988 ◽  
Vol 39 (2) ◽  
pp. 285 ◽  
Author(s):  
RW Sutherst ◽  
ID Sutherland ◽  
AS Bourne ◽  
GF Maywald ◽  
DA Stegeman

An experiment is described which compared the fluctuations in the numbers of cattle tick, Boophilus miicroplus, that resulted from direct climatic effects or from changes in host resistance. Four herds of cattle, matched for tick resistance and with different Bos indicus (zebu) content, were grazed at each of two locations, one in central Queensland (23� S.) and one in southern Queensland (28� S.), from November 1977 to May 1982. Natural tick populations were counted regularly, and host resistance was measured using artificial infestations, either twice or six times a year. Concurrent exposures of engorged ticks in pastures were used to measure the success of the ticks in producing larvae and to partition mortality during development. Two later papers report other aspccts of the experiment. These include observations on the resistance of cattle to ticks and on the relationship between tick numbers on the cattle on one hand, and the availability of larvae on pasture and survival of parasitic stages on the other. Engorged ticks produced more larvae throughout the year in central Queensland, despite laying fewer eggs. The colder and longer winter in southern Queensland greatly reduced tick reproduction. Failure of engorged ticks to survive predation and find a favourable oviposition site, egg mortality and loss of larvae in the pasture accounted for most of the reduction in the potential number of larvae produced. Reduced oviposition was also important in wintcr.

1975 ◽  
Vol 26 (6) ◽  
pp. 1073 ◽  
Author(s):  
BM Wagland

Four purebred Brahman and four beef Shorthorn cattle which had not previously been exposed to Boophilus microplus were infested four times with 20,000 B. microplus larvae. On first infestation, the yield of engorged female ticks on all animals was about 25% of the larvae applied. Aftcr three further infestations, the mean yield of engorged females on the Brahmans decreased to 7.5% whereas there was no decrease in the yield of ticks on the Shorthorns. On the Brahman cattle. development of larvae to engorged females took 1–2 days longer and the engorged females weighed less. However, there was no difference in the reproductive index of female ticks engorged on either Brahmans or Shorthorns. Increases in rectal temperatures occurred in all cattle 15–17 days after the first infestation and in some cattle on days 6–7 as well as on days 15–17 after reinfestation. It was concluded that resistance to B. microplus is an acquired phenomenon in Brahman cattle.


1978 ◽  
Vol 29 (2) ◽  
pp. 395 ◽  
Author(s):  
BM Wagland

The dynamics of host resistance to Boophilus microplus was investigated in previously unexposed and exposed Brahmans, and in previously unexposed Shorthorn cattle. The animals were infested each day with 1000 larvae, and the development of resistance was monitored by counting the number of female ticks which engorged. The previously unexposed cattle showed an initial period of susceptibility (phase I) which was followed by a period in which most animals developed degrees of resistance (phase II), and which stabilized in some animals (phase III). The duration of phase I was shorter in Brahmans, and they developed higher levels of resistance (phase III). In contrast, previously cxposed Brahmans manifested phase III levels of resistance immediately on infestation. The results provide further evidence that resistance to B. microplus in Brahmans, as well as in European breeds, is acquired rather than innate. __________________ *Part I, Aust. J. Agric. Res., 26: 1073 (1975).


1978 ◽  
Vol 29 (2) ◽  
pp. 401 ◽  
Author(s):  
BM Wagland

Length measurements were used to compare the growth of the parasitic stages of Boophilus microplus on previously unexposed Brahman (Bos indicus) and Shorthorn (B. taurus) cattle. Growth curves based on the length measurements were constructed. Growth was slower on Brahmans than on Shorthorns during the first 24 hr of larval and nymphal instars. After the first 24 hr, the growth rates of larvae, and of nymphs, during feeding to engorgement were the same on the rump and belly regions of both species of cattle. Larvae and nymphs engorged more slowly on the brisket than they did on the rump and belly regions of the Brahmans. The surface skin temperature was lower on the brisket of the Brahmans. On the basis of change in the length of the tick during development on Brahmans, 16 age categories were established, so that the length of the tick may be used to estimate the ages of ticks in populations on Brahman cattle. Age categories were also defined for ticks which had been processed in formalin and hot alkali. __________________ *Part II, Aust. J. Agric. Res., 29: 395 (1978).


1979 ◽  
Vol 30 (1) ◽  
pp. 211 ◽  
Author(s):  
BM Wagland

The stages of development of Boophilus microplus against which Brahman (Bos indicus) cattle manifest resistance were investigated by analysing the age distributions of ticks in populations on five steers showing different levels of resistance. The populations of ticks were established by infesting the steers each day with 1000 larvae, until each animal yielded a relatively stable number of engorged female ticks daily. The ticks were recovered by killing the steers and processing their hides in hot caustic soda. Ticks were allocated to age categories on the basis of their lengths. Analyses of the age distributions showed that between 36 and 80% of larvae were rejected in the first 24 h, and losses were greater from hosts with high levels of resistance. Some newly moulted nymphs failed to establish and were lost, and the growth of newly moulted females was retarded but most engorged successfully. The results also indicated that significant numbers of larvae and nymphs were lost either during the final stage of engorgement or after they had engorged. These findings are compared with losses of the tick from European (B. taurus) cattle. __________________ * Part III, Aust. J. Agric. Res., 29: 401 (1978).


1988 ◽  
Vol 39 (2) ◽  
pp. 299 ◽  
Author(s):  
RW Sutherst ◽  
GF Maywald ◽  
AS Bourne ◽  
ID Sutherland ◽  
DA Stegeman

The resistance to the cattle tick, Boophilus mircoplus, of four herds of cattle with different Bos indicus (zebu) content, grazed at each of two locations in the subtropics of Queensland, Australia, was measured using artificial tick infestations at intervals of either 2 or 6 months over periods of up to 4 years. The factors affecting resistance of crossbred herds at each location in order of decreasing importance were the proportion of R. indicus genes, lactation, age interacting with nutritional conditions, a seasonal cycle which differed in timing at the two locations, and rainfall during the week of tick infestation. These variables accounted for 62% of the observed variation and the statistical model explained concurrent changes in resistance of other herds equally well. These findings are combined with data on the survival of freeliving stages of the ticks in a later paper to explain the observed variation in populations of cattle ticks on the untreated herds when grazing in separate pastures.


1988 ◽  
Vol 39 (2) ◽  
pp. 309 ◽  
Author(s):  
AS Bourne ◽  
RW Sutherst ◽  
ID Sutherland ◽  
GF Maywald ◽  
DA Stegeman

The numbers of cattle ticks, Boophi1us microplus, were counted on cattle, with different Bos indicus (zebu) content in central and southern Queensland, from November 1977 to May 1982. Concurrently, measurements were made of the survival rates of parasitic stages of the tick and of the success of free-living stages in producing larval progeny. These measurements were related to the tick burdens on the cattle in order to test current understanding of the ecology of the tick.Tick numbers increased exponentially with decreasing Bos indicus content. Tick numbers built up very rapidly on the Bos taurus cattle and resulted in deaths early in the first season, so the herd was replaced with animals of 25% zebu content. The pure zebu animals carried an average of five ticks per animal per day in central Queensland and only one in southern Queensland. The 50% zebu herds carried 65 ticks per day in central Queensland and 1 l in southern Queensland, compared with 79 and 37 on the 25% zebu herds at the two locations. During their brief time in the experiment the B. taurus animals carried 465 and 302 ticks per day in central and southern Queensland respectively.The observed tick infestation levels were estimated to cause annual losses of liveweight gain of 1, 14 and 17 kg in zebu, 50% zebu and 25% zebu animals respectively in central Queensland. Comparative figures for southern Queensland were 0, 2 and 8 kg. Compensatory liveweight gain would have reduced these losses by up to 6 kg. These data relate to animals which were breeding most of the time and hence were less resistant than dry cattle. The results indicate that B. microplus has been reduced to a marginal problem on animals with 50% zebu genes in the region. It is therefore difficull to justify any control measures in southern areas, particularly when they could increase the risk of babesiosis. Owners of B. taurus cattle will continue to be at risk of major losses in productivity.Changes in the tick burden on the herd5 were explained mostly by changes in survival rates of parasitic ticks in central Queensland and by changes in availability of larvae on the pastures in southern Queensland.


1996 ◽  
Vol 36 (1) ◽  
pp. 9 ◽  
Author(s):  
G Fordyce ◽  
CJ Howitt ◽  
RG Holroyd ◽  
PK O'Rourke ◽  
KW Entwistle

The genetics of growth to 24 months, scrotal circumference (SC) at 24 months and temperaments at 6, 12 and 18 months in 7 year groups of F2 et seq., 1/2 Brahman, 1/2 Sahiwal, 3/4 Brahman and 3/4 Sahiwal bulls were investigated in the dry tropics of northern Queensland. Cattle tick (Boophilus microplus) and buffalo fly (Haematobia irritans exigua) resistance were also assessed at 24 months. Scrotal circumference at 24 months was highest in 1/2 Sahiwal crosses (28 cm v. 26-27 cm; P<0.05) with pronounced variation between years (24-31 cm; P<0.05). Temperaments (TEM score; flight distance) were generally poorest in 3/4 Sahiwal crosses (P<0.05). Bulls of 1/2 Bos indicus content were twice as susceptible as 3/4 crosses to tick infestations (P<0.05). There were no genotype differences in natural buffalo fly infestations. Temperaments, tick resistance and buffalo fly resistance all had no consistent significant relationships with either each other or with weights or growth rates to 24 months. Paternal half-sib estimates of heritabilities across all genotypes were generally moderate for weight (0.20-0.36), growth rates (0.08-0.46), and SC (0.32), low for TEM score (0.08-0.14), and high for flight distance (0.32-0.70). The genetic correlations (rG) between growth rates in both dry and wet seasons after weaning were high (>0.9); however, the rG of weaning weight with postweaning seasonal growth rates to 24 months were consistently negative (-0.09 to -0.71; P>0.05). The rG of SC with post-weaning growth rates were negative (-0.4 to -0.8). The rG of SC with weights up to 18 months were not significantly different to zero, but tended to be negative with weight at 24 months.


2019 ◽  
Vol 39 (11) ◽  
pp. 879-888
Author(s):  
Jaqueline P. Medeiros ◽  
Wanessa C. Bortollucci ◽  
Eloisa S. Silva ◽  
Herika L.M. Oliveira ◽  
Caio F.A.A. Campo ◽  
...  

ABSTRACT: Brazil has one of the largest commercial cattle herds in the world, which naturally coexist with an enormous number of parasitic species. Southern cattle tick, Rhipicephalus (Boophilus) microplus, is among these species, interfering with animal productivity and causing losses to the beef and dairy cattle sector. The use of chemical acaricides in the control of this mite has resulted in the emergence of resistant populations. In this sense, alternative control measures using plants as sources of botanical acaricides have shown to be effective. Eugenia pyriformis Cambess is a Brazilian plant with antioxidant and antimicrobial activity; however, there are no reports on its acaricidal activity in the literature. The present study aimed to evaluate the acaricidal and larvicidal potential of E. pyriformis leaf essential oil (EO) on southern cattle tick at different stages of the reproductive cycle. E. pyriformis leaves were collected and dried, and had their EO extracted by hydrodistillation (3h) using a modified Clevenger apparatus. Chemical analysis was performed by gas chromatography coupled with mass spectrometry (GC/MS), and 32 compounds belonging to the sesquiterpene class were identified: hydrocarbons (17.98%) and oxygenated forms (81.96%), with spathulenol (43.65%) and caryophyllene oxide (12.17%) as the most common. The EO was evaluated by the Adult Immersion Test at the concentrations (500.00 to 3.12mg/mL) in which the following parameters were measured: mortality of females (%), hatchability of eggs (%), and product efficiency (%). Larvae were assessed by the Larval Packet Test at concentrations ranging from 25.00 to 0.00004mg/mL. Lethal concentrations (LC) required for killing 50 and 99.9% of adult females and larvae were determined using Probit analysis. LC50 and LC99.9 of EO were 0.06 and 24.60mg/mL and 1,208.80 and 2,538mg/mL for larvae and adult females, respectively. Action of the EO in the free-living cycle of R. (B.) microplus larvae was another parameter assessed. To this end, the larvae were deposited in pots containing Brachiaria decumbens and, after migration to the leaf apex, a solution containing LC99.9 (24.60mg/mL) of the EO was sprayed. After 24h, 72.25% of the larvae had died, indicating stability of the EO when subjected to uncontrolled temperature and humidity conditions. The mechanism of action through which the EO killed the larvae and adult females was investigated by the Bioautographic Method, which showed inhibition of 3.15mg/mL of the EO on the acetylcholinesterase (AChE) enzyme. The results found in the present experiment indicate that E. pyriformis essential oil is an alternative in the control of southern cattle tick in the larval (parasitic) and free-living cycle (non-parasitic) stages under field conditions.


Parasitology ◽  
1971 ◽  
Vol 63 (2) ◽  
pp. 323-330 ◽  
Author(s):  
D. H. Kemp ◽  
D. Koudstall ◽  
J. D. Kerr

SUMMARYAfter 24 h desiccation at 28–29 °C and approximately 50 % relative humidity about 70 % of B. microplus larvae drank sufficient solution containing 1·5 mCi of 32P per ml for their movements on the host to be followed with a portable G-M counter. Reduced viability of the labelled ticks could not be detected when they were kept for 24 h on the host and either allowed to feed or prevented from doing so. When feeding was continued for 72 h or when larvae were incubated for 3–4 weeks, adverse effects were found, the severity of which could not be directly related to the amount of 32P label. Desiccation, handling of larvae and exposure to radiation in the drinking solution may have contributed to their reduced viability.Since resistance to the tick is manifest within the first 24 h after infestation labelled larvae could be used to compare development on different hosts during this time. Even after feeding for 72 h, larvae were more adversely affected by host resistance than by labelling damage.We would like to thank Mr C. A. Schuntner for helpful advice and Mrs J.Galligan for technical assistance. The financial support of the Australian Meat Research Committee is gratefully acknowledged. Messrs D. Hancox and S. R.Henderson assisted with some of the experiments.


2008 ◽  
Vol 126 (1-2) ◽  
pp. 110-119 ◽  
Author(s):  
Emily K. Piper ◽  
Louise A. Jackson ◽  
Neil H. Bagnall ◽  
Kritaya K. Kongsuwan ◽  
Ala E. Lew ◽  
...  

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