Mycophagy in small mammals: A comparison of the occurrence and diversity of hypogeal fungi in the diet of the long-nosed potoroo Potorous tridactylus and the bush rat Rattus fuscipes from southwestern Victoria,Australia

Abstract Three broad dietary categories—fungus, plant and arthropod—were identified from faecal samples of two species of small terrestrial mammal in forest vegetation in southwestern Victoria. Fungal material formed the major component of the diet of the long-nosed potoroo Potorous tridactylus throughout the year and of the bush rat Rattus fuscipes during autumn and winter. Fungal material was most abundant for both species during autumn and winter and significantly less common in spring and summer. These results confirm previous studies which found P. tridactylus to be highly mycophagous throughout the year and R. fuscipes to be strongly mycophagous seasonally. Particular consideration was given to the composition of fungi in the diet. Fungal spores in faecal material were assigned to spore classes, which represent one or more fungal species that have similar spore morphology. Twenty-four fungal spore classes were recorded, but for both animal species most of the fungi consumed were from seven major spore classes. The proportions of major spore classes in the diet of both animals were generally similar, even though the composition of spore classes differed markedly across seasons. Minor differences between species in the fungi consumed may be related to differences in selectivity, foraging, or microhabitat use. If fungal resources are limiting, competition for such resources may be important in this and other small mammal communities. The amount and diversity of hypogeal fungi consumed by the two animal species makes them both important spore dispersal agents in forest ecosystems. The capacity of R. fuscipes and other seasonally mycophagous mammals in this role may be more important than previously recognized, especially in habitats where species of the Potoroidae are absent.     

Using a species distribution model to guide NSW surveys of the long‐footed potoroo (Potorous longipes)

Knowledge of threatened species’ distributions is essential for effective conservation decision‐making. Species distribution models (SDMs) are widely used to map species’ geographic ranges, identify new areas of suitable habitat and guide field surveys. In New South Wales (NSW), Australia, there are grave doubts about whether populations of the critically endangered long‐footed potoroo (Potorous longipes) remain extant, and identification of occupied sites is a high priority for its conservation. We used an SDM (Maxent) to identify regions in NSW that may have suitable habitat for the potoroo. The SDM was built with seven climate layers and had strong predictive performance (cross‐validated AUC = 0.94). We then combined this information on habitat suitability with vegetation and topography, to identify 58 survey sites across NSW. From April 2016 to May 2017, we undertook six field trips deploying six to eight cameras at each site for 52–63 days, resulting in 25 120 camera trap nights. A total of 215 759 images captured 43 native and feral animal species, but no long‐footed potoroos. Following the survey, newly available, independent presence and absence data were used to validate our model. A Kruskal–Wallis H test indicated that habitat suitability values were significantly higher at presence locations than absence locations (H = 58.66, d.f. = 1, P < 0.001). Finally, we refitted the Maxent model with the new data and identified additional regions that future surveys could explore. We conclude, however, that if the long‐footed potoroo remains extant in NSW, it is extremely rare.     

Further observations on the potoroo (Potorous tridactylus) in captivity

The maintenance and breeding performance of potoroos in captivity over a 7-year period is described. By removing offspring from the pouch and allowing 29 days for completion of embryonic development and birth to occur, pouch young of known ages can be obtained.     

Mycophagy among Australian mammals

Abstract This review provides a synthesis, from published and unpublished sources, of records of mycophagy (fungus-feeding) by Australian mammals. Mycophagy is shown to be widespread among Australian mammals, paralleling the previously well-documented situation in North America. Mycophagy appears to be most prevalent within the Potoroidae (rat-kangaroo family) but has also been recorded for a variety of other mammals. Information is presented on the classification, morphology and ecology of the fungi consumed, on the nutritional benefits (or otherwise) of mycophagy, and on the role of mammals in spore dispersal. Fungi whose sporocarps are hypogeal (truffles, false-truffles and sporocarpic Endogonaceae) and which enter into mycorrhizal relationships with plants predominate among the species recorded in mammal diets.     

Fire and habitat management for a mycophagous marsupial,the Tasmanian bettong Bettongia gaimardi

Abstract The Tasmanian bettong, Bettongia gaimardi, is a mycophagous marsupial that occurs in fire-prone dry sclerophyll forests. Previous studies have demonstrated that some of the hypogeous fungi on which it feeds become abundant soon after fire, and have suggested that it might depend on regular burning of its habitat. The longer-term effects of burning on B. gaimardi and its food supply were evaluated by comparing six sites, matched for soil, vegetation and climate, in southeastern Tasmania that had been left unburnt for periods ranging from 1 to 50 years. At each site, the density of B. gaimardi diggings was measured and sporocarps of hypogeous fungi were surveyed. Abundance of hypogeous sporo-carps was low at sites 2 years or less post-fire, but was high at sites 4 years and more post-fire. Species richness was similarly low at recently burnt sites, an effect that was due to the absence of many shallow-fruiting taxa. All species (with one exception) present at recently burnt sites were also present in long-unburnt sites. Densities of B. gaimardi diggings were highest at a very recently burnt (<1 year) site and at a site left unburnt for 10 years. These trends suggest that a high frequency of burning may be unfavourable to B. gaimardi in the forest type investigated in this study.     

Balanoposthitis, dyspareunia, and treponema in the critically endangered Gilbert's potoroo (Potorous gilbertii)

The Gilbert's potoroo (Potorous gilbertii) is one of Australia's most critically endangered mammals with a current estimated population of 70 individuals. Both the wild and captive populations have a long history of balanoposthitis with associated crusting, ulceration, and preputial discharge. We sought to identify the microbial species found in the discharge, determine their significance in causing balanoposthitis, and correlate these findings with reproductive success and survivorship. Bacteriologic examination revealed the discharge to be a polymicrobial infection involving Treponema spp., Actinobacillus spp., and Pasteurella spp. Preputial histopathology reported a moderate, chronic, erosive inflammatory response with diffuse, moderate to marked secondary epithelial hyperplasia in conjunction with moderate numbers of spirochetes, suggesting a causative relationship. Clinical examination, preputial biopsies, and serologic screening found no evidence of associated systemic disease. The clinical investigation of Treponema is significant with respect to the overall recovery of Gilbert's potoroo, given the clinical and histopathologic similarities to Treponema paraluis-cuniculi found in rabbits, causing dyspareunia, and the severity of the associated balanoposthitis.     

Effect of cadmium on the reproductive organs of the male potoroo Potorous tridactylus (macropodidae)

Low (2.28 mg/kg) or high (4.56 mg/kg) doses of cadmium chloride were administered, either intraperitoneally or subcutaneously, to adult male potoroos (P. tridactylus). After 7 days, the testes, caput epididymis and spermatic cords of the high-dose groups all displayed a degree of cellular damage; however, the damage was not as extensive as that which occurs in some eutherian species after only 24 h. This time differential might be attributed to structural differences between the testicular blood supply in eutherians and marsupials.     

Studies on the Stellaria longipes complex (Caryophyllaceae): relationships among the species based on seed protein profiles

CHINNAPPA, C. C, GIFFORD, D. J. & RAMAMORRTHY, J., 1992. Studies on the Stellaria longipes complex (Caryophyllaceae): relationships among the species based on seed protein profiles. The protein profiles of nine genera of the family Caryophyllaceae show distinct patterns. Within the genus Stellaria , six species were studied. The four North American species show more or less similar profiles, while the two European species have quite different patterns. There are some indications to suggest that the polyploid species, 5. longipes , is closely related to diploid S. longifolia and S. porsildii. The seed protein profiles of these species support the view that 5. longipes might have originated from hybridization between the two diploid species.     

Dietary variation of an endangered mycophagous mammal in novel and remnant habitats in a peri-urban landscape

Understanding how fundamental aspects of species’ ecology, such as diet, are affected in human-dominated landscapes is vital for informing management and conserving biodiversity – particularly where species influence important ecosystem functions. Digging, mycophagous (‘fungus-eating’) mammals play various such roles, including the dispersal of hypogeal (‘truffle-like’) fungi. The endangered, mycophagous southern brown bandicoot (Isoodon obesulus obesulus: Peramelidae) persists in a peri-urban landscape south-east of Melbourne, Australia, where it occupies both ‘novel’ habitats (linear strips of vegetation along roadsides, drains and railway lines) and ‘remnant’ habitats (larger blocks of native vegetation) within dedicated conservation areas. It remains unknown how bandicoot diet, including the diversity of hypogeal fungi, varies between these habitat types, yet this could have important conservation implications. Our study aimed to (i) compare the diet of I. o. obesulus at novel and remnant sites; and (ii) attain knowledge of hypogeal fungal diversity in these different contexts. We collected 133 bandicoot scats over 23 months and examined both broad diet composition and diversity of fungi consumed. Bandicoot diet differed between site types; in particular, ants were more prominent in scats from remnant sites, while millipedes and seeds were more prominent in scats from novel sites. All scats contained fungal spores, with hypogeal taxa comprising at least 35 of the 78 ‘morphotypes’ found at novel sites and 28 of the 59 detected at remnant sites. Fewer samples were collected at remnant sites, but they appeared to contain a greater richness of hypogeal fungi per scat. We did not detect any differences in fungal composition between site types. However, our sampling effort was insufficient to estimate true morphotype richness at either site type. Our study highlights the adaptable generalist diet of the southern brown bandicoot, as well as the likely under-appreciated diversity of hypogeal fungi that can occur in highly modified, novel ecosystems.     

湖南省衡东县发现长指鼠耳蝠

2016年8月27日在湖南省衡阳市衡东县四方山林场仙妃洞（26°58′25″N,113°3′23″E,海拔463 m）采到1只鼠耳蝠标本（1♂）;同年8月29日在金觉峰（26°58′24.4″N,113°3′23.1″E,海拔311 m）采到9只鼠耳蝠标本（4♀,5♂）。上述鼠耳蝠标本形态较小,前臂长33.3 ~ 36.1 mm,其后足长（不包括爪长）长于胫长之半,胫外缘有毛;颅全长13.57 ~ 14.35 mm,头骨粗壮,脑颅圆且较高,明显高过上颌骨。经形态和线粒体Cyt b序列鉴定,确认这10只蝙蝠均为蝙蝠科（Vespertilionidac）鼠耳蝠属（Myotis）的长指鼠耳蝠（M. longipes）,该种为湖南省翼手目分布新记录种,标本（编号,4♀为HUNNU16JJ28、HUNNU16JJ42、HUNNU16JJ43、HUNNU16JJ52,6♂为HUNNU16SF25、HUNNU16JJ05、HUNNU16JJ08、HUNNU16JJ51、HUNNU16JJ58、HUNNU16JJ60）保存于湖南师范大学动物标本室。     

Isolation and characterization of nine polymorphic microsatellite loci in the endangered shrub Disanthus cercidifolius var. longipes (Hamamelidaceae)

Nine polymorphic microsatellite loci were isolated and characterized from an AC-enriched genomic library of Disanthus cercidifolius var. longipes. Microsatellite polymorphism was investigated using 24 individuals from one natural population. The observed number of alleles per locus ranged from two to four. Observed and expected heterozygosities ranged from 0.17 to 0.92 and from 0.16 to 0.72, respectively. These polymorphic microsatellite loci provide useful tools for the ongoing population genetic studies of D. cercidifolius var. longipes.     

Modeling mycorrhizal fungi dispersal by the mycophagous swamp wallaby (Wallabia bicolor)

Despite the importance of mammal‐fungal interactions, tools to estimate the mammal‐assisted dispersal distances of fungi are lacking. Many mammals actively consume fungal fruiting bodies, the spores of which remain viable after passage through their digestive tract. Many of these fungi form symbiotic relationships with trees and provide an array of other key ecosystem functions. We present a flexible, general model to predict the distance a mycophagous mammal would disperse fungal spores. We modeled the probability of spore dispersal by combining animal movement data from GPS telemetry with data on spore gut‐retention time. We test this model using an exemplar generalist mycophagist, the swamp wallaby (Wallabia bicolor). We show that swamp wallabies disperse fungal spores hundreds of meters—and occasionally up to 1,265 m—from the point of consumption, distances that are ecologically significant for many mycorrhizal fungi. In addition to highlighting the ecological importance of swamp wallabies as dispersers of mycorrhizal fungi in eastern Australia, our simple modeling approach provides a novel and effective way of empirically describing spore dispersal by a mycophagous animal. This approach is applicable to the study of other animal‐fungi interactions in other ecosystems.     

Detecting a genetic bottleneck in Gilbert's Potoroo (Potorous gilbertii) (Marsupialia: Potoroidae), inferred from microsatellite and mitochondrial DNA sequence data

Gilbert's Potoroo isAustralia's most critically endangeredmarsupial, known from a single population inthe Two Peoples Bay National Park in WesternAustralia. We present results from a study ofgenetic variation in microsatellite andmitochondrial DNA. Mean heterozygosity at fivemicrosatellite loci was 49.3%, and the amountof mtDNA variation was extremely low ( =0.0004). There was evidence for a bottleneckin both sets of markers, and this wasconsistent with a demographic decline. Effective population size was estimated usingtwo different models of mutation formicrosatellites (N _e = 243 and 362). The results from this study highlight theconcern for the long-term survival of thisspecies.     

Relationships between floral morphology and pollinator fauna in insular and main island populations of Hosta longipes (Liliaceae)

We compared the floral morphologies and pollinator fauna and morphologies of Hosta longipes var. longipes on the main Japanese island of Honshu and var. latifolia on the Izu Islands to examine the differentiation processes of H. longipes in the island system. The corolla length was shorter on the southern Izu Islands than on the main island and northern Izu Islands. However, the size of other flower parts of H. longipes did not simply decrease across main island Honshu and the Izu Islands, unlike other Izu endemic plant species studied previously. Instead, the floral morphology showed a complicated variation pattern. Pollinator fauna of H. longipes on the Izu Islands varied more widely than those on the main island. The diverse pollinator fauna may have influenced the morphological differentiation of H. longipes on these islands.     

广东省发现长指鼠耳蝠及其回声定位声波特征

2013年7月在广东南岭国家级自然保护区阳山县境内(24°48′39.5′′N,112°51′01.3′′E,海拔155 m)捕捉到4只雄性蝙蝠,体型小,前臂长34.1~34.7 mm,颅全长14.3~14.7 mm;体毛浓密,背毛毛基黑色,毛尖灰色,腹毛黑或棕色,毛尖奶油白,靠近肛门处腹毛浅灰色,些许白色;翼膜附着于跖部末端;后足特别延展,长度超过胫骨长之半;鉴定为长指鼠耳蝠[Myotis longipes(Dobson1873)]。同时,基于Cyt b基因序列(1 140 bp)构建的部分鼠耳蝠物种系统进化关系,进一步确认上述标本为长指鼠耳蝠,为广东省翼手目新纪录。该种蝙蝠在我国贵州、广西、重庆有分布记载,但标本和相关资料很少。本文给出了长指鼠耳蝠的外形和头骨特征测量数据,并与印度的标本进行了对比。长指鼠耳蝠的回声定位声波为调频型(FM),主频率为68.2 k Hz;此外,对其分类地位和分布状况进行了讨论。标本保存于广东省生物资源应用研究所。     

Patterns of vegetative growth and gene flow in Rhizopogon vinicolor and R. vesiculosus (Boletales, Basidiomycota)

We have collected sporocarps and tuberculate ectomycorrhizae of both Rhizopogon vinicolor and Rhizopogon vesiculosus from three 50 x 100 m plots located at Mary's Peak in the Oregon Coast Range (USA); linear map distances between plots ranged from c. 1 km to c. 5.5 km. Six and seven previously developed microsatellite markers were used to map the approximate size and distribution of R. vinicolor and R. vesiculosus genets, respectively. Genetic structure within plots was analysed using spatial autocorrelation analyses. No significant clustering of similar genotypes was detected in either species when redundant samples from the same genets were culled from the data sets. In contrast, strong clustering was detected in R. vesiculosus when all samples were analysed, but not in R. vinicolor. These results demonstrate that isolation by distance does not occur in either species at the intraplot sampling scale and that clonal propagation (vegetative growth) is significantly more prevalent in R. vesiculosus than in R. vinicolor. Significant genetic differentiation was detected between some of the plots and appeared greater in the more clonal species R. vesiculosus with Phi(ST) values ranging from 0.010 to 0.078*** than in R. vinicolor with Phi(ST) values ranging from -0.002 to 0.022** (*P < 0.05, **P < 0.01, ***P < 0.001). When tested against the null hypothesis of no relationship between individuals, parentage analysis detected seven likely parent/offspring pairs in R. vinicolor and four in R. vesiculosus (alpha = 0.001). Of these 11 possible parent/offspring pairs, only two R. vinicolor pairs were still supported as parent/offspring when tested against the alternative hypothesis of being full siblings (alpha = 0.05). In the latter two cases, parent and offspring were located at approximately 45 m and 28 m from each other. Challenges to parentage analysis in ectomycorrhizal fungi are discussed.     

Establishment of ectomycorrhizae on the roots of two species of Eucalyptus from fungal spores contained in the faeces of the long-nosed potoroo (Potorous tridactylus)

Abstract The long-nosed potoroo (Potorous tridactylus), a medium-sized, ground-dwelling marsupial, inhabits the foothills and coastal forests of southeastern mainland Australia. Faecal analysis confirmed the mycophagous habit of P. tridactylus at a eucalypt forest site in East Gippsland, Victoria; in one month, the spores of 33 different fungi were identified. The majority of species (27) were hypogeal or subhypogeal gasteromycetes that form ectomycorrhizae with forest trees and shrubs, and included the widespread and common Mesophellia pachytrix. The possible role of mycophagy in establishment of eucalypt-fungal mycorrhizae was investigated in several ways. Fungal spores were viable after passage through the gut of P. tridactylus; application of spore-bearing faeces to seedlings of Eucalyptus sieberi and Eucalyptus globoidea grown in sterile soil produced ectomycorrhizae. Spores of M. pachythrix were among the most common spores in these faeces and some of the resulting ectomycorrhizae were of the type expected from M. pachythrix. In contrast, direct application of M. pachythrix spores from sporocarp tissue to seedlings produced no ectomycorrhizae. Ectomycorrhizae also were established on seedlings grown in unsterilized forest soil, indicating that soil-borne spores had been conditioned, either by passage through the gut of a mammal or some other means, for reaction with the roots of eucalypts. Addition of faeces improved root and shoot growth of seedlings, although we could not determine whether this was primarily due to the formation of ectomycorrhizae, the addition of nutrients in the faeces, or a combination of both. Potorous tridactylus may enhance the re-establishment of mycorrhizal colonies in logged and/or burned forest sites by dispersing in its faeces, the spores of mycorrhizal fungi from sporocarps consumed within the disturbed area, as well as spores from sporocarps eaten in adjacent undisturbed habitat. In performing this function, P. tridactylus may also aid in the recovery of regenerating silvertop ash-stringybark forests.     

The type and time of occurrence of aminopterin-induced chromosome aberrations in cultured Potorous cells

Many inhibitors of DNA synthesis have been found to induce chromosome aberrations. Our kinetic studies indicate that treatment of cellswith 10^?7M aminopterin in the presence of 10^?4M glycine, 10^?4M hypoxanthine, and 10^?4M thymidine allows continued normal cell growth. Omission of thymidine, a treatment which is known to inhibit DNA synthesis while allowing RNA and protein synthesis to continue, leads to cessation of cell growth. Treament of Potorous cell cultures with aminopterin in the presence of hypoxanthine and glycine without thymidine led to the following observations: (1) only non-exchange chromatid aberrations were formed after aminopterin treatment; (2) the aberrations were induced only in cells treated during S, and the breaks were associated with the replicating region of the chromosome; (3) breaks were observed at the first metaphase after the beginning of treatment; and (4) thymidine could reverse the chromosome-breaking action of aminopterin. A model for the molecular mechanism is suggested.