Lowered adrenal responsiveness in an island population of Rattus fuscipes (waterhouse), an Australian rodent

1977 ◽  
Vol 32 (2) ◽  
pp. 117-119 ◽  
Author(s):  
J.L. Barnett
1989 ◽  
Vol 16 (1) ◽  
pp. 33 ◽  
Author(s):  
MC Calver ◽  
JC Mcilroy ◽  
DR King ◽  
JS Bradley ◽  
JL Gardner

The susceptibility of eight species of dasyurid marsupials and five species of murid rodents from the pastoral areas of Western Australia to the toxin sodium monofluoroacetate (Compound 1080) was assessed. Both LD*5O tests and an increasing dose procedure to determine the approximate lethal dose (ALD) were used. The results ranged from a low ALD of 1.6 mg kg-1 for an island population of Pseudomys hermannsburgensis to a high of 20 mg kg-1 for a mainland population of Notomys mitchelli. Intraspecific and regional variation in sensitivity was evident: three populations of P. hermannsburgensis showed widely different ALDS, and high ALDS were found in the Millstream area relative to elsewhere in the pastoral regions. Where both ALD and LD*5O were available, the dose response curve was steep; all LDSOS were less than a factor of 1.5 above the ALD. LD*5O values and ALDS were significantly correlated for selected dasyurids and murids, using published data. A computer simulation based on sampling a standard number of animals from 10 theoretical populations differing only in their LD~O confirmed that ALD and LD*5O gave similar rankings of sensitivity, although high variance on the LD~O reduced the strength of the correlation. Actual dosing data from eight populations of Rattus fuscipes were also analysed; both LD*5O and ALD gave similar rankings of population sensitivity. Subject to assumptions about the variability of sensitivity within a population, the ALD offers an alternative to LD~O testing that requires fewer animals, and need not cause more than one death per population tested.


Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.


Heredity ◽  
2006 ◽  
Vol 97 (1) ◽  
pp. 56-65 ◽  
Author(s):  
D H Nussey ◽  
J Pemberton ◽  
A Donald ◽  
L E B Kruuk

Author(s):  
Coby Klein ◽  
Mitchell Baker ◽  
Andrei Alyokhin ◽  
David Mota-Sanchez

Abstract Eastern New York State is frequently the site of Colorado potato beetle (Leptinotarsa decemlineata, Say) populations with the highest observed levels of insecticide resistance to a range of active ingredients. The dominance of a resistant phenotype will affect its rate of increase and the potential for management. On organic farms on Long Island, L. decemlineata evolved high levels of resistance to spinosad in a short period of time and that resistance has spread across the eastern part of the Island. Resistance has also emerged in other parts of the country as well. To clarify the level of dominance or recessiveness of spinosad resistance in different parts of the United States and how resistance differs in separate beetle populations, we sampled in 2010 beetle populations from Maine, Michigan, and Long Island. In addition, a highly resistant Long Island population was assessed in 2012. All populations were hybridized with a laboratory-susceptible strain to determine dominance. None of the populations sampled in 2010 were significantly different from additive resistance, but the Long Island population sampled in 2012 was not significantly different from fully recessive. Recessive inheritance of high-level resistance may help manage its increase.


1986 ◽  
Vol 123 (3) ◽  
pp. 424-430 ◽  
Author(s):  
JEFFREY R. HARRIS ◽  
SCOTT D. HOLMBERG ◽  
ROBERT D. R. PARKER ◽  
DALE E. KAY ◽  
TIMOTHY J. BARRETT ◽  
...  
Keyword(s):  

1987 ◽  
Vol 14 (2) ◽  
pp. 163 ◽  
Author(s):  
D. Lunney ◽  
B. Cullis ◽  
P. Eby

This study of the effects of logging on small mammals in Mumbulla State Forest on the south coast of New South Wales included the effects of a fire in November 1980 and a drought throughout the study period from June 1980 to June 1983. Rattus fuscipes was sensitive to change: logging had a significant impact on its numbers, response to ground cover, and recapture rate; fire had a more severe effect, and drought retarded the post-fire recovery of the population. The three species of dasyurid marsupials differed markedly in their response to ground cover, canopy cover, logging and fire. Antechinus stuartii was distributed evenly through all habitats and was not affected by logging, but fire had an immediate and adverse effect which was sustained by the intense drought. A. swainsonii markedly preferred the regenerating forest, and was not seen again after the fire, the failure of the population being attributed to its dependence on dense ground cover. Sminthopsis leucopus was found in low numbers, appeared to prefer forest with sparse ground cover, and showed no immediate response to logging or fire; its disappearance by the third year post-fire suggests that regenerating forest is inimical to the survival of this species. Mus musculus showed no response to logging. In the first year following the fire its numbers were still very low, but in the next year there was a short-lived plague which coincided with the only respite in the 3-year drought and, importantly, occurred in the intensely burnt parts of the forest. The options for managing this forest for the conservation of small mammals include minimising fire, retaining unlogged forest, extending the time over which alternate coupes are logged and minimising disturbance from heavy machinery.


1995 ◽  
Vol 46 (3) ◽  
pp. 583 ◽  
Author(s):  
RJQ Tarr

Growth rates of a number of Haliotis midae populations around the South African coast were studied by means of tagging. These populations ranged from the cool waters of the western coast to the more temperate environment of the eastern Cape. Standard von Bertalanffy growth curves were fitted and growth parameters derived. These ranged from 0.19 to 0.25 for K, the average rate at which L∞ is approached, and from 156 to 173 for L∞, the average theoretical maximum length. These indicate far higher growth rates than were previously published for this commercially fished species, and the reasons for this difference are discussed. The expectation that growth rates would be fastest in the warmer eastern Cape waters was not realized, there being no significant difference in growth between the Bird Island population on the eastern coast and the Robben Island population on the western coast. These new growth parameters indicate that H. midae in the commercial fishery grounds is attaining sexual maturity some four years earlier, and the minimum legal size some five years earlier, than previously considered. This has considerable significance for modelling studies presently underway. Movement of a small population of adult H. midae was studied over a three-year period, after which 47% of the original abalone were still present on the study site. Of these, 81.5% still occupied exactly the same position on the rocks. This indicates that H. midae that have located an optimum habitat, and that are not disturbed, tend not to move.


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