68.

Little Forest Bat

Vespadelus vulturnus

French: Vespertilion sylvestre / German: Kleine Waldfledermaus / Spanish: Vespadela silvestre

Other common names: Little Bat, Little Brown Bat, Small Forest Eptesicus, Vulturine Little Bat

Taxonomy. Eptesicus pumilus vulturnus Thomas, 1914,

Tasmania, Australia .

Vespadelus vulturnus previously included V. baverstocki, but their specific status is supported by morphological data. Based on abrupt differences in echolocation calls between different populations, there may be cryptic species included within what 1s currently recognized as V. vulturnus . Monotypic.

Distribution. SE Australia, in SE Queensland, New South Wales, Victoria, and SE South Australia; also Flinders I and Tasmania.

Descriptive notes. Head-body 34-7-48 mm, tail 27-5-34-2 mm, ear 9-1-12: 2 mm, forearm 23-5-32-8 mm; weight 2:6-6-5 g. Pelage is variable; dorsal pelage varies from brown to pale gray (hairs bicolored, darker basally and creamy white to brown or gray on top one-third); ventral pelage is lighter. Ears, membranes, and face are pale brown (membranes can be dark blackish brown), and forearms are lighter than the membranes. Ears are small and rounded triangular with a smoothly convex anterior edge; tragus is narrow, anteriorly straight or slightly concave, posteriorly convex, and with rounded tip and slight posterobasal lobe; tragus is usually distinctly white or pale gray. Uropatagium reaches to tip of tail. Penis is pendulous and glans is distinctly round and bulbous; urethral opening is at anteroventral aspect of glans and covered by a spatulate lobe rising from either side of mid-ventral edge of opening. Baculum is long (mean 4-4 mm), with dorsally rod-shaped shaft and moderately expanded base with deep bifurcation to one-quarter of total length; deflected ventrally a little at base, and sharply at tip in lateral view. Skull is of moderate length; lambdoidal crest is weakly to moderately developed; anterior narial notch is narrow or broad U-shaped or V-shaped; rostrum is comparatively long; I? is bicuspid, I® is unicuspid; P* is much smaller than C' and within tooth row; crista linking base of metacone and hypocone on M' is absent or slight, and absent or slight on M*. Karyotype is 2n = 44.

Habitat. Found in a variety of habitats including wet and dry sclerophyll forest, river red gum ( Eucalyptus camaldulensis, Myrtaceae) forest, montane and dry woodlands, blackwood swamps, brigalow, mulga ( Acacia, Fabaceae), and mallee, typically closer to riverine habitats in more arid regions. Recorded from sea level to 1100 m, although apparently commonest below 400 m.

Food and Feeding. Little Forest Bats forage in upper levels of forest understory or in spaces between trees, and regularly come very close to foliage. They are highly maneuverable and do spirals and gliding arcs when changing direction to catch prey. They almost always catch prey while it is flying, presumably by aerial-hawking. Most prey is eaten on the wing, but larger prey may be taken to a feeding roost to be eaten. Diet is highly variable, based on abundance and diversity of prey in surrounding habitats; this can change over the seasons. A recent study found the species would changeits foraging habitat based on prey availability (particularly that of the mosquito Aedes vigilax), using saltmarsh habitats when mosquito abundance was higher but foraging elsewhere when mosquito abundance was low. Little Forest Bats regularly feed on moths, true bugs, and beetles, which make up most of the diet in most areas, but they also take some flies, wasps, termites, ants, and cockroaches, and rarely spiders, grasshoppers, and lacewings.

Breeding. Breeding occurs during autumn and also winter. Spermatogenesis occurs during summer, and males will continue to store sperm throughout winter, remaining reproductively active. Little Forest Bats will arouse from hibernation to mate. Females also store sperm in the uterus, which is aided by a copulatory plug that forms in the vagina after mating. However, sperm is sometimes lost in the female’s reproductive trap and matings during winter can ensure that it is replaced. During winter, a follicle is present but ovulation is delayed until spring. Litter size is usually one, occasionally two. Births occur in late November or December. Lactating females are commonly found during December and January. Young are left in the roost while the female forages. Volant young are caught foraging with the females by mid-January. Females become sexually mature in their first year, males in their second. In southern Tasmania, births occur c¢.1 month later than in mainland populations.

Activity patterns. Little Forest Bats leave their roosts at dusk to forage through the night. During winter, they hibernate in a torpid state, allowing them to leave hibernation to forage and breed. Their activity is highly dependent on ambient temperature, and during a cold spell they may not leave the roost to forage for weeks at a time. Males arouse from torpor more frequently than females, often to mate. The species roosts in narrow hollows in dead trees or dead branches of live trees, generally with several entrances; these are usually very small or narrow (only slightly larger than the bat itself). Call shape is FM/QCF andis variable across the distribution. There are three starkly different calls: south-eastern and central Queensland (characteristic frequency 43-47 kHz); coastal New South Wales (44-49 kHz); and southern New South Wales (49-53 kHz).

Movements, Home range and Social organization. Little Forest Bats may roost singly or in colonies of up to 120 individuals. Roosts are sexually segregated, although juveniles and occasional adult males can be found in female colonies. The bats typically do not change roosts very often, and may occupy the same roost throughout an entire year. They will travel up to 1-5 km from day roosts to forage at specific locations.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Overall, there are no major threats currently affecting the Little Forest Bat, although land clearing for agriculture is a threat locally (e.g. in northern New South Wales).

Bibliography. Campbell et al. (2005), Churchill (2008), Gonsalves et al. (2013), Kitchener et al. (1987), Law & Chidel (2000), Law et al. (2002), Lumsden & Bennett (1995, 2005), Lumsden & Pennay (2008), O'Neill & Taylor (1986), Rueeggeret al. (2018), Taylor et al. (1987), Tidemann (1982, 1993), Tidemann & Flavel (1987), Tidemann et al. (2008), Volleth & Tidemann (1989), Willis et al. (2005), Young & Ford (1998).