Home range, denning behaviour and microhabitat use of the carnivorous marsupial Dasyurus maculatus in eastern Australia

Radio-tracking of spotted-tailed quolls Dasyurus maculatus (Marsupialia: Dasyuridae) in the forested ranges of north-eastern New South Wales revealed that home ranges were extensive, with males occupying large, overlapping ranges [minimum convex polygon (MCP) up to 757 ha] and females occupying smaller, non-overlapping territories (MCP up to 175 ha). Quolls were partly arboreal, although most activity occurred on the ground or on fallen logs. Hollow logs were most frequently used as dens, but rock crevices, burrows, tree hollows and artificial structures were also used. Individual quolls were located in up to nine different dens and, with the exception of maternal dens, rarely sheltered in the same location on successive days. The large home ranges of the spotted-tailed quoll and the non-overlapping nature of female ranges necessitate very large areas of habitat to support viable populations. Fallen timber, used extensively for shelter and in travelling, may serve to enhance the quality of habitat for the species, and should be retained by forest and wildlife managers.     

Who's your daddy? Paternity testing reveals promiscuity and multiple paternity in the carnivorous marsupial Dasyurus maculatus (Marsupialia: Dasyuridae)

Female promiscuity is common among mammals but its advantages, particularly for marsupials, remain unclear. Using microsatellite DNA from pouch young of known mothers, we identified the most likely fathers of 25 wild spotted-tailed quolls ( Dasyurus maculatus ) from six litters. We aimed to determine whether young within the same litter had different fathers, and whether breeding success of males was associated with large body mass (consistent with inter-male competition) or scrotal width (consistent with sperm competition). We also explored the possible influence of promiscuity on relatedness within litters. Finally, we used data on paternity and relatedness to make inferences regarding movement and dispersal.
Four litters were sired by more than one male, and three males sired offspring in more than one litter. Known fathers had higher body mass, but not scrotal width, than males of unknown paternity status, suggesting that males may compete for access to females. Sires were less related to dams than expected by chance, and litters with multiple paternity had lower relatedness than litters sired by a single male.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 1–7.     

Cross‐species amplification at microsatellite loci in Australian quolls including the description of five new markers from the Chuditch (Dasyurus geoffroii)

The quolls are the largest native predators remaining on mainland Australia. We describe the cross‐species testing of all available microsatellite loci for representative across the entire distribution of quolls, with the additional characterization of five new microsatellite loci from the Chuditch. All primers produced clear and polymorphic amplification patterns containing between nine and 17 alleles and with high levels of diagnostic variability. These highly polymorphic primers make them useful additional tools in planning conservation strategies across related conspecifics, many of which are under threat.     

Out of the frying pan: Reintroduction of toad‐smart northern quolls to southern Kakadu National Park

Invasive species are a leading cause of native biodiversity loss. In Australia, the toxic, invasive cane toad Rhinella marina has caused massive and widespread declines of northern quolls Dasyurus hallucatus. Quolls are fatally poisoned if they mistakenly prey on adult toads. To prevent the extinction of this native dasyurid from the Top End, an insurance population was set up in 2003 on two toad‐free islands in Arnhem Land. In 2015, quolls were collected from one of these islands (Astell) for reintroduction. We used conditioned taste aversion to render 22 of these toad‐naïve quolls toad averse. Seven quolls received no taste aversion training. The source island was also predator‐free, so all quolls received very basic predator‐aversion training. In an attempt to re‐establish the mainland population, we reintroduced these 29 northern quolls into Kakadu National Park in northern Australia where cane toads have been established for 13 years. The difference in survival between toad‐averse and toad‐naive quolls was immediately apparent. Toad‐naive quolls were almost all killed by toads within 3 days. Toad‐averse quolls, on the other hand, not only survived longer but also were recorded mating. Our predator training, however, was far less effective. Dingo predation accounted for a significant proportion of toad‐smart quoll mortality. In Kakadu, dingoes have been responsible for high levels of quoll predation in the past and reintroduced animals are often vulnerable to predation‐mediated population extinction. Dingoes may also be more effective predators in fire degraded landscapes. Together, these factors could explain the extreme predation mortality that we witnessed. In addition, predator aversion may have been lost from the predator‐free island populations. These possibilities are not mutually exclusive but need to be investigated because they have clear bearing on the long‐term recovery of the endangered northern quoll.     

PCR-based sex test for Xiphophorus maculatus

A simple reliable PCR-based sex test for the platyfish Xiphophorus maculatus is described using sex chromosome-linked molecular markers. The test can distinguish sexes prior to dimorphic differentiation without killing the fish. The method also has potential in identification of male and female embryos prior to birth.     

Aspects of the biology of Galaxias maculatus

The biology of three landlocked and a riverine population of Galaxias maculatus were examined in western Victoria, Australia. All systems supported reproducing populations of these fish, including Lake Corangamite which had salinities that on occasion reached 82. Spawning sites in Lake Corangamite were located in adjacent tributaries and not in the main lake as was the case for other populations. The smallest fish were found in the fresh water Lake Purrumbete and the largest in the hypersaline Lake Corangamite. The size at which 50% of the population attained sexual maturity varied across sites, with fish maturing at a smaller size in Lake Purrumbete, followed by the Merri River, Lake Bullen Merri and Lake Corangamite. Condition was higher in the freshwater Lake Purrumbete and there was no relationship between condition and temperature, conductivity, turbidity and pH; but there was a positive relationship between condition and dissolved oxygen. Length frequency analysis suggested that the majority of fishes live for a year.     

Acoustic homogeneity in the piranha Serrasalmus maculatus

Different studies suggest some social calls could be used in fish identification if their specificity is unambiguously assessed. Sounds of different populations of piranhas Serrasalmus maculatus Kner, 1858 were recorded to determine their homogeneity between rivers inside a single basin (Araguari and Grande River, upper Paraná River basin) and between separated basins (Amazon and Paraná basins). All fish from the different populations produced sounds with similar acoustic features. Consequently, the populations were not discernible based on individual sound characteristics. This high homogeneity between sounds from different populations indicates their usefulness for conservation projects using passive acoustic monitoring in piranhas. Moreover, it supports the use of acoustic features as complementary key characteristics in taxonomic studies.     

Ground dwelling mammal response to fire: A case study from Monga National Park after the 2019/2020 Clyde Mountain fire

Ground dwelling mammal communities are documented six months before and after the Clyde Mountain Wildfire of 2019/2020 in Monga National Park. Across eight sites before fire, approximately 12 ground dwelling mammal species were recorded. Survey effort post-fire increased to 40 sites, spanning three fire severity classes (low, moderate and extreme), revealed 16 ground dwelling mammal species. Species consist of small, medium and large native (one threatened species) and introduced mammals, though consistent with previous findings of ground dwelling mammal diversity in the area. Overall a greater number of species were found in low, compared to moderate and severe fire severity classes. Recovery and detection of mammals occurred in a shorter time period, again, in sites that experienced low, followed by moderate and extreme fire severity.     

Space use and temporal partitioning of sympatric Tasmanian devils and spotted‐tailed quolls

Sympatric species can minimise interspecific competition by spatial avoidance or by altering their temporal activity to reduce encounter rates. The Tasmanian devil (Sarcophilus harrisii), the largest carnivorous marsupial, coexists with the smaller spotted‐tailed quoll (Dasyurus maculatus) in Tasmania, Australia. Quolls may be susceptible to interspecific competition from devils, because they utilise similar habitats, consume similar prey species and are displaced by devils at food sources. Such competition might cause quolls to spatially or temporally avoid devils. To investigate whether spatial or temporal avoidance occurred, we deployed GPS collars on sympatric devils and quolls and conducted a camera survey at a site in northwest Tasmania where the devil population was not affected by devil facial tumour disease. GPS tracking coincided with the lactation period when devils and quolls had young in dens and continued until weaning occurred. We found little spatial segregation of home range and core area placement between devils and quolls and among devils. Quolls showed more spatial segregation within the sexes than between them. Devils had larger home ranges than quolls. Male devils had larger home ranges than females, but there was no difference in home range size between the sexes of quolls. Females of both species travelled significantly further per night than did males. There was moderate temporal partitioning between the two species: devil activity peaked after dusk and devils remained active until the early morning, while quoll activity showed distinct peaks around dusk and dawn. In conclusion, quolls did not spatially avoid devils but moderate temporal partitioning occurred. It is plausible that quolls are active at different times of the diel cycle to reduce encountering devils, but further studies are needed to resolve the cause of this temporal partitioning.     

敌百虫对中国花鲈的毒性效应

为了给中国花鲈(Lateolabrax maculatus)病害防治提供根据,研究了不同浓度的敌百虫对中国花鲈鱼苗和幼鱼的急性毒性,检测了幼鱼肝脏的谷胱甘肽(GSH)、丙二醛(MDA)含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)和乙酰胆碱酯酶(AChE)活力,测定了暴露在不同浓度敌百虫中幼鱼的红细胞总核异率和微核率.结果表明:敌百虫对中国花鲈鱼苗24、48、72和96h的半致死浓度分别为7.76、3.02、1.74和1.58 mg·L-1,安全浓度为0.14 mg·L-1;对幼鱼24、48、72和96 h的半致死浓度分别为10.96、6.15、3.98和2.89 mg·L-1,安全浓度为0.58 mg·L-1.濒死的中国花鲈肝脏组织有溶解性坏死灶.幼鱼在不同浓度的敌百虫中暴露48 h,随着敌百虫浓度的升高GSH含量先下降后恢复再下降;MDA含量先上升后恢复;各组SOD活力与对照组比较无显著的差异;CAT活力先下降后恢复;GPT活力维持在低水平;GOT活力在1.35和2.70 mg·L-1实验组下降;AChE活力先下降后略回升.GSH和MDA含量以及CAT、GPT、GOT和AChE活力对敌百虫胁迫敏感而SOD活力则不敏感;幼鱼在敌百虫浓度为1.45mg·L-1的实验组中暴露96 h,其红细胞的总核异率与对照组比较显著升高(P＜0.05);在0.73 mg·L-1实验组中暴露96 h,红细胞的微核率与对照组比较显著升高(P＜0.05).     

Fragment chromosomes in Myrmeleotettix maculatus (Thunb.)

Structural changes involving fragmentation and the deletion of chromosome material have resulted in the production of morphological variants of the standard B chromosomes of Myrmeleotettix maculatus. Three distinct types are described — a considerably reduced B^st chromosome with a sub-terminal centromere and a large and small telocentric fragment. In addition, the B^st chromosome can itself give rise to a small telocentric fragment. The fact that such telocentric fragments have been found only in mosaic germ lines implies a lack of stability and an inability to perpetuate themselves between generations. The non-reciprocal translocation of one such fragment onto the short arm of a metacentric autosome does little to improve the efficiency of its transmission from one generation to another. The behaviour of autosomal fragments, discovered in both the M₆ and S₈ chromosomes of this species, parallels that of B fragments. Only the B^st chromosomes appear both mitotically and meiotically stable.     

Growth and reproduction of the highfin grouper Epinephelus maculatus

Highfin grouper Epinephelus maculatus sampled in Chuuk, Micronesia, exhibited a moderate growth rate and a relatively short life span compared to other epinephelids of a similar size. Combined gonad and otolith analysis provide preliminary evidence that the species conforms to a protogynous sexual pattern. Mean total length at maturity for females was 308 mm with first age at maturity 2·8 years for females and 4 years for males, which differs from other regional studies. Based on the gonado‐somatic index and microscopic analysis of gonads, E. maculatus in Chuuk have a 4 month spawning season (January to April) that corresponds with seasonal lows in sea surface water temperature and overlaps with that of other aggregating epinephelids. The estimated von Bertalanffy growth factor (K) was 0·51 year^?1, while total mortality was 0·34 year^?1. Current management for E. maculatus in Chuuk includes a January to May catch, sale and export ban, which overlaps with its reproductive season. The effectiveness of these arrangements will require on‐going monitoring to determine whether alternative management strategies are required to ensure population persistence.     

Egg dumping and life history strategy of Callosobruchus maculatus

Abstract.  Previous studies have demonstrated that female Callosobruchus maculatus adjust oviposition rates to cope with changes in host availability. A female lays fewer eggs when host availability is low, and hence decreases larval competition. However, females will also dump eggs on unsuitable substrates under conditions of host deprivation. Because the female does not feed as an adult, egg dumping possibly wastes energy and may thus be a maladaptive behaviour. In this study, the effect of mating and age on the egg-dumping behaviour and the life history strategy of the female are explored. Under host-deprived conditions, mating is seen to trigger egg-dumping behaviour. Also, females mated at 6 days dump significantly fewer eggs and live longer than females mated at 0 or 3 days. Thus, a trade-off between fecundity and longevity is seen among females subjected to different manipulations. In addition, 6-day-old virgin females contain more mature eggs than females mated at 6 days can produce when deprived of hosts. This finding indicates that the female reallocates internal energy resources by oosorption in a resource-limited environment. To test the maladaptive hypothesis, mated females were deprived of a host for 6 days and then given sufficient hosts each day. The results show that the more eggs dumped by a female in the first 6 days, the more eggs are laid later on beans. Egg dumping is thus not maladaptive.     

Vocalization of the tree frogPolypedates maculatus (Rhacophoridae)

The period of calling activity ofPolypedates maculatus lies between April and October. Males possess an indistinct subgular vocal sac which turns yellow during the breeding season. Mating calls type I, type II and distress calls have been identified. Mating calls type I and type II consist of a single pulse group. Type I call comprises of 7–22 pulses, whereas type II call consists of 4–6 pulses. Pulses are short. The frequency spectrum is broad and continuous. Distress calls, with 6 hormonics, are given by the females with their mouth open.