Nyctophilus bifax, Thomas, 1915

Don E. Wilson & Russell A. Mittermeier, 2019, Vespertilionidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 716-981 : 805

87.

Eastern Long-eared Bat

Nyctophilus bifax

French: Nyctophile du Queensland / German: Queensland-Langohrfledermaus / Spanish: Nictofila de Queensland

Other common names: Bifax Long-eared Bat

Taxonomy. Nyctophilus bifax Thomas, 1915 ,

“Herberton,” Far North Queensland, Australia.

Nyctophilus bifax is in the bifaxspecies group along with N. arnhemensis and tentatively N. shirleyae . The bifax species group might best be included with the macrotis species group based on morphology. Nyctophilusdaedalus generally has been considered a subspecies of N. bifax , but morphological data support their distinction at the species level. Records of N. bifaxin New Guinea likely represent an undescribed species of Nyctophilus rather than N. bifax , but additional studies are needed. Monotypic.

Distribution. E Queensland (including Moa, Prince of Wales, Hinchinbrook, Palm, and Fraser Is) and NE New South Wales, E Australia, and a few scattered records across New Guinea that require validation.

Descriptive notes. Head—body 35-55 mm, tail 39-46 mm, ear 19-2-27-1 mm, forearm 37-5-46-8mm; weight 5-12 g. The Eastern Long-eared Bat has very large ears and unique simple noseleaf consisting of two ridges, one further on muzzle and another immediately above nostrils, with vertical groove in middle and furred trough between them. Dorsal pelage is rich brownish tan; venteris lighter. Face, ears, and wing membranes are dark grayish brown. Rostrum is short and blunt, with ridge across muzzle over nostrils that is poorly developed with only slight medial depression. Ears are very large and broad, with bluntly rounded tips, having horizontal ribbing on inner surfaces, inward curved anterior edges, and smooth posterior edges (ears can fold back at top of thick part of anterior edge); large and furred interauricular band crosses forehead between ears; tragus is small and bluntly rounded attip, being convex on anterior margin. Glans penisis a square-ended cylinder, with flat circular urethral opening on underside near tip. Baculum is 3-3-3-7 mm long, with moderately thin shaft in dorsal view; tip is deeply bifurcated, and base is strongly bifurcated;in lateral view, baculum is curved downward at base, but shaft is straight to pointed tip. Skull is robust and relatively narrower than in the Pallid Long-eared Bat (N. daedalus ), tympanic bullae are small, and M? and lower molars are moderately reduced but less reduced than in the Pallid Long-eared Bat.

Habitat. Preferring wet habitats, including rainforests, monsoon forests, and paperbark ( Melaleuca , Myrtaceae ) riverine forests, and also open woodlands, tall open forests, and dry sclerophyll woodlands from sea level up to elevations of 500 m (in Queensland).

Food and Feeding. Eastern Long-eared Bats rely on perch-hunting to catch prey, hanging 5-10 m aboveground and pivoting their bodies back and forth while echolocating or active listening. When foraging, they make flights of less than 3 m to catch prey. They can catch their prey aerially or by gleaning off the ground orfoliage. They switch perches many times throughout the night and appear to move after 3-5 minutes without detecting prey. New perch is usually within 50 m from the one they just moved from. Eastern Long-eared Bats forage along edges of canopies rather than within foliage. Moths appear to make up large parts of diets based on stomach and fecal samples, but trace amounts of ants and click beetles have also been recorded. In captivity, they readily eat mealworms.

Breeding. Eastern L.ong-eared Bats breed in May and give birth to twins in October; lactation occurs in October-December. Young remain attached to the female for the first couple of days and then are left in the roost while females forage at night. Twins combined weight can be as much as 95% of the mothers’ weight when sheis carrying them.

Activity patterns. Eastern Long-eared Bats spend the day roosting under peeling bark, amongst epiphytes, in tree hollows, in shallow depressions on trunks and branches, in strangler fig roots, among dead fronds of prickly tree ferns, and in various other foliage types. They occasionally roost in buildings. During lactation, females prefer using tree hollows to foliage for roosts, but foliage roosts are used more commonly during mating season. In New South Wales, they switch roosting localities between seasons, moving to cooler interiors of forests in late spring (November) and warmer forest edges in late autumn (May). Roosts are usually within 250 m of one another. Capture rates are highest in the first hour after sunset because they are leaving roosts then and traveling to foraging areas. During times of stress and during the day, Eastern LLong-eared Bats are able to enter torpor to conserve energy. During breeding season, pregnant females entered torporless frequently than males. This might be to prevent as much slowed fetal development as possible because going into torpor delays fetal development, which could cause an energetic disadvantage. During winter, they hibernate by staying in torporfor prolonged periods, although they regularly leave roosts to forage. In a study comparing torpor bouts in tropical and subtropical environments during winter, Eastern Long-eared Bats spent more time in torpor in subtropical environments (mean 26-8 hours; maximum 83-7 hours) than in tropical environments (mean 4-5 hours; maximum 11-4 hours), with minimum daily ambient temperatures of 14-7°C and 20-1°C,respectively. In summerin a subtropical region in Iluka Nature Reserve, they used torpor 85% of the observed days and 38% of nights, ranging in length from 0-7 hours to 21-2 hours. In winter in the same region, torpor was used on 100% of observed days, and torpor duration increased as ambient temperature decreased. There was little correlation between torpor duration and ambient temperature in summer, which were highly negatively correlated in winter. In summer, mean torpor duration was 3-2 hours, but in winter, it was 26-8 hours. Use of torpor might be used to avoid predation in fit individuals because they have the bodily resources to avoid foraging, which decreases overall risk of predation. Basal metabolic rate of Eastern Long-eared Bats in subtropical regions at ambient temperatures of 32:5°C was 1-3 ml O,/g/h in summer and winter. Thermal energetics did not vary seasonally, and individuals from subtropical areas allowed their body temperatures to fall significantly lower than those in tropical areas. Call shape is steep FM sweep, with maximum frequencies of 70-109 kHz (mean 89-1 kHz) and minimum frequencies of 47-55 kHz, which is higher than in other longeared bats butstill similar enough to make identification by echolocation alone difficult.

Movements, Home range and Social organization. The Eastern Long-eared Bat generally roosts in sex-segregated roosts. Females roost in small colonies of 2-7 individuals; males usually roost alone. Both sexes change roosts often but show strong preference for making their roosts in a cluster oftrees.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Eastern Long-eared Bat is widespread and does not seem to face any major threats. It might be locally threatened by roost disturbance and deforestation.

Bibliography. Bonaccorso (1998), Churchill (2008), Churchill et al. (1984), Flannery (1995b), Hutson, Schlitter, Csorba, Hall, McKenzie & Parnaby (2008), Lunney et al. (1995), Parnaby (1987 2009), Parnaby & Churchill (2008), Schulz & Oliveira (1995), Stawski (2010, 2012a, 2012b), Stawski & Geiser (2010a, 2010b, 2011, 2012), Stawski et al. (2009), Woodside & Taylor (1986).

Figures

78. New Guinea Big-eared Bat (Pharotis imogene), 79. Western Long-eared Bat (Nyctophilus major), 80. Corben’s Long-eared Bat (Nyctophilus corbeni), 81. Pallid Long-eared Bat (Nyctophilus daedalus), 82. Gould’s Long-eared Bat (Nyctophilus gouldi), 83. Tasmanian Long-eared Bat (Nyctophilus sherrini), 84. New Caledonian Long-eared Bat (Nyctophilus nebulosus), 85. Papuan Long-eared Bat (Nyctophilus macrotis), 86. Pygmy Long-eared Bat (Nyctophilus walkeri), 87. Eastern Long-eared Bat (Nyctophilus bifax), 88. Northern Long-eared Bat (Nyctophilus arnhemensis), 89. Mount Missim Long-eared Bat (Nyctophilus shirleyae), 90. Small-toothed Long-eared Bat (Nyctophilus microdon), 91. Lesser Long-eared Bat (Nyctophilus geoffroyi), 92. Sunda Long-eared Bat (Nyctophilus heran), 93. Lord Howe Long-eared Bat (Nyctophilus howensis)

Distribution. E Queensland (including Moa, Prince of Wales, Hinchinbrook, Palm, and Fraser Is) and NE New South Wales, E Australia , and a few scattered records across New Guinea that require validation.