Miniopterus australis, Tomes, 1858

Don E. Wilson & Russell A. Mittermeier, 2019, Miniopteridae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 674-709 : 696-697

11.

Little Long-fingered Bat

Miniopterus australis

French: Minioptére australasien / German: Kleine Australische Langfligelfledermaus / Spanish: Miniéptero australiano

Other common names: Little Bent-winged Bat

Taxonomy. Miniopteris [sic] australis Tomes, 1858 ,

Lifu Island, Loyalty Islands, New Caledonia .

Miniopterus australis is in the australis complex, which once grouped all small species of Miniopterus from Asia, Australia, and Melanesia. This complex is now split, and most of taxa considered as subspecies of M. australis are now considered valid species ( M. macrocneme , M. paululus , M. pusillus , and M. shortridger). Taxonomic status of the complex is still not completely resolved and requires an in-depth genetic study of its components. Placement of populations from Borneo, Sulawesi, and Ambon in relation to M. paululus and M. pusillus is especially confusing. Available mtDNA sequences indicate that populations of Vanuatu and Australia are quite differentiated from each other, and several subspecies will probably be recognized in the future. Monotypic.

Distribution. Borneo, Sulawesi, Moluccas (Bacan, Seram, and Ambon Is), Aru Is, New Guinea (including Waigeo I), Admiralty Is (Manus I), Bismarck Archipelago (New Britain I), Louisiade Archipelago (Trobriand and Woodlark Is), Solomon Is, Vanuatu, New Caledonia (including Loyalty Is), and E coast of Australia from Cape York to N New South Wales (including Possession, Magnetic, and Bribie Is).

Descriptive notes. Head-body 36-48 mm, tail 38-50 mm, ear 8-5-12 mm, hindfoot 6-5-9 mm, forearm 35-41 mm; weight 5-6-5 g. Pelage of the Little Long-fingered Bat is uniform chocolate-brown to dark brown on dorsum,slightly lighter on venter. It occasionally has large reddish patches due to ammonia effect on pelage in large nursery colonies. Ears are short, and tragus (3-2—-6-3 mm) has parallel edges on basal one-half, strong forward curvature on distal one-half, and serrated upper margin. Skin of muzzle, ears, wings, forearms, and hindfeet is dark brown. The Little Long-fingered Bat is smaller than the Small Melanesian Long-fingered Bat ( M. macrocneme ) and the Small Long-fingered Bat ( M. pusillus ) and somewhat larger than the Philippine Longfingered Bat ( M. paululus ) and Shortridge’s Long-fingered Bat (M. shortridger). Diploid number is 2n = 46 (Sabah, Borneo).

Habitat. Subtropical rainforests, wet and dry sclerophyllous forests, coastal forests, river and coastal scrubs, and human settlements from sea level to elevations of ¢. 1500 m. The Little Long-fingered Bat is cave dwelling, and although it is more common in limestone areas, it is less strict than other species of Miniopterus in terms of roost selection. In Australia, it roosts near extensive areas of relatively dense vegetation. A colony of ¢.30 individuals was found in a large hollow in a 30m soapy box tree ( Citronella moorei, Cardiopteridaceae ) in Australia.

Food and Feeding. The Little Long-fingered Bat is an aerial hawker, foraging mainly in open spaces. Nevertheless, it has a relatively low wing loading (5-8 N/m?) that allows it to fly rapidly and with considerable maneuverability between shrub and canopy layers of densely wooded areas. Nematoceranflies, ants, moths, and wasps were found in three stomachs from specimens in Papua New Guinea and Australia.

Breeding. Reproductive cycle ofthe Little Long-fingered Bat has been studied in several areas within its wide distribution. It was always seasonally monoestrous, with only one young per pregnancy and synchronization of births within each population. Delayed implantation has not been found at any latitude, but in different places, reproductive cycle has some peculiarities. In northern New South Wales at the southern limit ofits distribution (28°30 °-31° S), a silent heat (ovulation without fertilization and prior to behavioral estrus and insemination) occurs in April. Males have spermatogenesis from April to the end ofJuly and store sperm in epididymides from mid-May to mid-September. Copulatory behavioris first noted at the end ofJuly with conception occurring in mid-August, and implantation occurs within a month. Births occur in December. In Espiritu Santo Island, Vanuatu (15°15 S), copulation takes place from mid-August to the beginning of September, and gestation lasts c.4 months until mid-December. In New Caledonia (21° S), cycle is delayed c.1 month with respect to Vanuatu. In all these cases, cycle is adjusted to austral seasonality. In Borneo (4° N), with little variation in daylength but already in the Northern Hemisphere, apparently the cycle is boreal, with ovulation in the first one-half of December and births in late April and early May after a pregnancy of c.5 months. In this case, gestation and births of Little Long-fingered Bats coincide with nesting of most birds that feed their young with insects. It has been suggested that a period of post-implantation delay is responsible for extended gestation in Borneo compared with other places. In Sulawesi (Mangolo Reserve, 4° S) in the Southern Hemisphere, two of three females were pregnant in November, suggesting a southern cycle. In New South Wales, Little Long-fingered Bats share maternity colonies and cluster with much greater numbers of the Australian Long-fingered Bat ( Miniopterus orianae oceanensis), benefitting from this larger species’ ability to increase roost temperatures from metabolic heat. Temperature at the roost can be as high as 39°C, which favors growth of altricial young. As in other Miniopterus , young Little Longfingered Bats are born naked and blind, and they fledge at c.7 weeks of age. Females do not get pregnantin their first year of life in New South Wales, but in Borneo, they can breed in the first year.

Activity patterns. The Little Long-fingered Bat begins activity ¢.20 minutes before sunset in Vanuatu, flying inside the roost first. Emergence begins c.10 minutes before sunset and lasts ¢.20 minutes, leaving at a rate of ¢.120-150 ind/minute. Large numbers of individuals return to the roost at ¢.02:00 h. In Vanuatu, Little Long-fingered Bats are active year-round, but in subtropical habitats at the southern limit of the distribution in New South Wales, they decrease activity significantly during austral winter (July-August) and are torpid only on the coldest days. In contrast, other less tropical species—like the Australian Long-fingered Bat—in the same area, with which they share roosts, show a more intense hibernation. In addition to caves, mines, and tunnels, Little Long-fingered Bats use tree cavities as roosts. Little Long-fingered Bats are occasionally found in houses and other artificial roosts (not totally dark) and culverts in New Caledonia. Echolocation calls have downward FM signals, with end frequency slightly above 50 kHz in New Caledonia.

Movements, Home range and Social organization. It is said that the Little Long-fingered Bat can migrate, but the longest movement recorded—made by two females between nursery roost and another secondary roost—was 60 km in New South Wales. Very large maternity colonies with ¢.100,000 individuals are known in Borneo and Queensland (Mount Etna Cave), but figures ofless than 10,000 females are more common. After the breeding season, a colony disperses to secondary roosts located within its territory. In Borneo, another type of social organization has been described. Little Long-fingered Bats are distributed inside the cave in small groups of less than ten individuals in erosion holes. These groups are considered harems because they are composed of one male and up to six females. This structure is maintained throughout the year, from the breeding period to reproductive inactivity. Groups are not stable in terms of composition or in their use of particular erosion holes in the cave. Little Long-fingered Bats often share roost with other cave-dwelling bats such as species of Rhinolophus, Hipposideros, or other Miniopterus .

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Bonaccorso (1998), Churchill (2008), Dwyer (1968), Furman, Oztung & Coraman (2010), Harada & Kobayashi (1980), Hughes etal. (2011), Kirsch et al. (2002), Kitchener & Suyanto (2002), Medway (1971), Payne et al. (2007), Phillipps & Phillipps (2016), Revilliod (1914), Rhodes (2002), Richardson (1977), Rosell-Ambal, Tabaranza, Pennay et al. (2008), Sanborn & Nicholson (1950), Schulz (1997b), Sramek etal. (2013), Suyanto & Struebig (2007), Tomes (1858a), Vestjens & Hall (1977), Wiantoro et al. (2017).

Figures

1. Asian Long-fingered Bat (Miniopterus fuliginosus), 2. Large Long-fingered Bat (Miniopterus magnater), 3. Small Long-fingered Bat (Miniopterus pusillus), 4. Intermediate Long-fingered Bat (Miniopterus meduius), 5. Ryukyu Long-fingered Bat (Miniopterus fuscus), 6. Eschscholtz’s Long-fingered Bat (Miniopterus eschscholtzii), 7. Philippine Long-fingered Bat (Miniopterus paululus), 8. Great Long-fingered Bat (Miniopterus tristis), 9. Shortridge’s Long-fingered Bat (Miniopterus shortridgei), 10. Javanese Long-fingered Bat (Miniopterus blepotis), 11. Little Long-fingered Bat (Miniopterus australis), 12. Small Melanesian Long-fingered Bat (Miniopterus macrocneme), 13. Loyalty Long-fingered Bat (Miniopterus robustior), 14. Australian Long-fingered Bat (Miniopterus orianae), 15. Pallid Long-fingered Bat (Miniopterus pallidus), 16. Schreibers’s Long-fingered Bat (Miniopterus schreibersu), 17. Neghrohion Long-fingered Bat (Miniopterus maghrebensis)

Distribution. Borneo, Sulawesi, Moluccas (Bacan, Seram, and Ambon Is), Aru Is, New Guinea (including Waigeo I), Admiralty Is (Manus I), Bismarck Archipelago (New Britain I), Louisiade Archipelago (Trobriand and Woodlark Is), Solomon Is, Vanuatu , New Caledonia (including Loyalty Is), and E coast of Australia from Cape York to N New South Wales (including Possession, Magnetic, and Bribie Is).