91.

Lesser Long-eared Bat

Nyctophilus geoffroyi

French: Nyctophile de Geoffroy / German: Geoffroy-Langohrfledermaus / Spanish: Nictofila de Geoffroy

Taxonomy. Nyctophilus geoffroyi Leach, 1821,

type locality not given.

Nyctophilus geoffroyi is in the geoffroyi group that also tentatively includes N. heran, but this is not well established. Three subspecies are tentatively recognized, but they are not well defined morphologically or geographically.

Subspecies and Distribution.

N.g.geoffroyiLeach,1821—WAustralia.

N.g.pacificusJ.E.Gray,1831—E&SAustraliaandTasmaniaexceptNECoastofQueenslandandapparentlyincludesFraser,Kangaroo,King,andFlindersIs.

N. g. pallescens Thomas, 1913 — N & C Australia.

Descriptive notes. Head-body 38-50-2 mm, tail 31-40-5 mm, ear 17-6-25-3 mm, forearm 30-6—41-7 mm; weight 3-9-14-5 g. The Lesser 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 light gray; venter is white. Face, ears, and wing membranes are dark brown. Rostrum is short and blunt, with ridge across muzzle over nostrils that is well developed and high, with two mounds and elastic membrane of skin between them, giving it a distinctive Y-shaped groove. Ears are very large and broad, with bluntly rounded tips, 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 at tip, being convex on anterior margin. Glans penis has distinctive serrated longitudinal dorsal ridge on distal part. Baculum has moderately thin shaft in dorsal view, tapering to non-bifurcated tip, base being strongly bifurcated; in lateral view, baculum is curved downward at base, but shaftis straight to pointed tip. Skull is comparatively gracile for the genus, tympanic bullae are relatively inflated, and M” and M, are moderately reduced.

Habitat. Various habitats including deserts, tropical to alpine woodlands, mangroves, grasslands, agricultural land, urban areas, wet to dry sclerophyll forests, and rainforests from sea level up to elevations of ¢. 1580 m (in Victoria).

Food and Feeding. The Lesser Long-eared Bat catches prey by gleaning and catching it aerially. It uses shortrange echolocation, which is very efficient in picking up textures of objects rather than distance and direction, adding to the evidence that they are gleaners. It has occasionally been captured in pitfall traps, probably being attracted to sounds of captured insects. Although echolocation is still important for prey detection, it likely uses passive listening and visual cues to detect and capture aerial and gleaned prey. Flight is slow and fluttering but with a high degree of maneuverability. Individuals can make quick gliding changes in direction or drop vertically while flying (sometimes within centimeters from the ground) to catch prey aerially. Flight speeds while foraging are much slower than in nearly any other bat species at only 4 km /h, but speeds of 20 km /h are reached while commuting to foraging areas. The Lesser Long-eared Bat is capable of taking off from the ground by jumping straight horizontally and flying. It feeds on a wide variety of insects, but moths, crickets, and grasshoppers appear to be most commonly eaten. Other prey items include wingless ants, cricket nymphs,spiders, beetles, cockroaches, true bugs,flies, and lacewings. It probably exploits calls of katydids seasonally for hunting by passive listening, which its large ears are well designed for.

Breeding. Lesser Long-eared Bats breed once a year and form maternity colonies during this ime. Spermatogenesis begins in November, peaks in March, and ends in May, but sperm is then stored in epididymides as testes regress. Sperm competition has been observed. Copulation usually starts in April, butthis varies by region. Femalesstore sperm in uterine lining and oviducts over winter until ovulation, fertilization, and implantation take place in late August or September. Gestation lasts 72-93 days and probably changes depending on how much time females spend in torpor. Females usually give birth to twins in late October and November. Births can occur earlier at lowerlatitudes and elevations. By December, young are generally volant, and females are no longer lactating. In Tasmania, lactation was reported for a shorter period of time. Notall females reproduce each year.

Activity patterns. Lesser Long-eared Bats are nocturnal. During warm months, they become active shortly after dark and remain active until dawn; in colder months, they might only be active for c.1 hour/day. They roost in dead trees, under tree bark, under rocks, in bird nests (specifically fairy martins, Petrochelidon ariel), in caves, and in buildings; they are very reluctant to give up roosting sites, even in the face of extreme disturbance—a behavior that accounts in part for their ability to live near humans. Lesser Long-eared Bats can enter torpor during the day and through winter for various durations to deal with excessive heat or cold. Ambient temperature under which they enter torpor decreases at lower latitudes, being ¢.15°C in Tasmania and ¢.25°C on the mainland. As ambient temperature decreases, metabolic rate increases below the thermoneutral zone. Call shape is very steep FM sweep, with peak frequencies of 47-48 kHz (mean 47-7 kHz), and it is very difficult to distinguish it from other long-eared bats.

Movements, Home range and Social organization. Lesser Long-eared Bats generally roost in small colonies of 2-3 bats or alone throughoutthe year, but gender composition varies regionally and seasonally. They form maternity colonies in spring that can have up to 200 individuals, but they generally only form colonies of 10-15 individuals.

As they begin to form maternity colonies, a single male will often roost with females to mate with them.

Status and Conservation. Classified as Least Concern on The [UCN Red List. The Lesser Long-eared Bat is the most widely distributed bat species in Australia, being found nearly throughout the continent, and is found in large numbers in most regions. It is common throughout most ofits distribution but less common in northern parts.

Bibliography. Bailey & Haythornthwaite (1998), Brigham, Francis & Hamdorf (1997), Bullen & McKenzie (2002a), Churchill (2008), Churchill et al. (1984), Dixon & Rose (2003), Fullard et al. (1991), Fuller (2013), Geiser & Brigham (2000), Hosken (1996, 1997b, 1998), Hosken & Withers (1999), Lumsden & Bennet (1995, 1996), Lumsden & Tur bill (2008), Lumsden, Bennett & Silins (2002a, 2002b), Lumsden, Hall et al. (2008), McKenzie et al. (2002), O'Neill & Taylor (1989), Parnaby (2009), Strahan (1983), Tidemann & Flavel (1987), Turbill (2006b), Turbill & Geiser (2006).