Pipistrellus pygmaeus

Pipistrellus pygmaeus

The soprano pipistrelle (Pipistrellus pygmaeus Leach, 1825) is a bat belonging to the Vespertilionidae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Animalia,
Phylum Chordata,
Mammalia class,
Superorder Laurasiatheria,
Order Chiroptera,
Suborder Microchiroptera,
Family Vespertilionidae,
Subfamily Vespertilioninae,
Genus Pipistrellus,
Species P. pygmaeus.
The terms are synonymous:
– Vespertilio mediterraneus Cabrera, 1904;
– Vespertilio pygmaeus Leach, 1825.
Within this species, two subspecies are recognised:
P. pygmaeus pygmaeus: present in Portugal, Spain, south-western and central-eastern France, Corsica, Great Britain, Ireland, north-western Switzerland, northern Austria, central Germany, eastern Denmark, Poland, Czech Republic, Slovakia, northern Hungary , Central Italy, Sardinia, Slovenia; Bosnia and Herzegovina, northern Croatia and Serbia, Greece, Rhodes Island, northwestern and central Romania, southern Moldova, eastern Ukraine, northern Belarus, Lithuania, Latvia, Estonia; southern Sweden and Norway, Armenia, Azerbaijan, Georgia and southwestern Russia;
P. pygmaeus cyprius (Benda, 2007): present in Cyprus.
This species has recently been separated from the nominal species in light of molecular differences and echolocation configuration, with frequencies generally lower than the latter.

Geographic Distribution and Habitat –
The Pipistrellus pygmaeus is a bat widespread in Europe and present from Portugal to the Caucasus in the east and the southern part of the Scandinavian peninsula in the north. In Italy it is present in Abruzzo, Lazio, Campania and Sardinia.

Description –
The Pipistrellus pygmaeus is a small bat, with the length of the head and body between 36 and 51 mm, the length of the forearm between 28 and 33 mm, the length of the tail between 23 and 36 mm, the length of the ears between 9 and 13 mm and a weight of up to 8 g.
It is recognized for having dense and silky fur. The dorsal parts vary from brown to reddish-brown, while the ventral parts are yellowish-grey.
The snout is broad, with two glandular masses on the sides and a deep furrow between the nostrils. The eyes are small. The ears are short, triangular, well separated from each other and with a rounded tip. The tragus is short, with the rounded end curved slightly forward. The wing membranes are clear and opaque. The tail is long and is completely included in the large uropatagium, which is densely covered with hair at the base. The calcar is long and has a small lobe. The penis is slightly bulbous.
This bat emits high-duty-cycle ultrasound in the form of short-duration pulses of near-constant frequency initial 50–64.7 kHz, final 52–57 kHz, and maximum energy at 55.5 kHz.

Biology –
The mating of this bat occurs in late summer and autumn.
Pipistrellus pygmaeus females gather in maternity colonies while they are pregnant and nursing their young. This causes a problem for the human population because these colonies can get quite large, in fact much larger than Pipistrellus pipistrellus colonies, which tend to be fewer than 200 bats. This large colony size causes annoyance to humans due to the odor. During the early stages of pregnancy, Pipistrellus pygmaeus emerges later from its roost than at the end of pregnancy or during breastfeeding. This may be due to the large size of this bat’s colonies.
Early pregnancy occurs in May, late pregnancy occurs in June and July, while breastfeeding occurs in August.
At the end of the pregnancy they give birth to one baby, more rarely twins, at the end of June or beginning of July. Life expectancy is approximately 12 years.

Ecological Role –
The Pipistrellus pygmaeus finds its habitat, throughout Europe, on roofs and in houses. One study, conducted by Lourneco and Palmeirim, suggested that the reason for the preference for roofs was due to the thermal differences available across the entire roof. Although these bats can thermoregulate up to 40 degrees Celsius, they prefer not to exceed this temperature. Roofs give maternity colonies access to cooler places on hot days and warmer places at other times. This was discovered by using different colored bat boxes and seeing how commonly each was used.
In a study conducted by Nicholls and Racey, the habitat of this species was found to be small, approximately 487 hectares. It consisted primarily of agricultural land, but also saw a significant increase in woodland edges and grasslands used as habitat. When it came to foraging habitat, however, these bats significantly preferred riparian woodlands over all other habitats. Hunting areas can be 4-10 km away from the roost. Water followed in second place, and these two habitats combined made up “77% of foraging time.” (Nicholls and Racey).
As for its eating habits, this bat uses only a small portion of its territory to obtain food and is generally close to its daytime roost. Perhaps due to the preference for foraging in a riparian habitat, many times these bats are seen overlapping each other’s foraging areas. During reproduction and breastfeeding, foraging occurs with longer flights, with similar flight times, but fewer attacks compared to Pipistrellus pipistrellus. This is likely due to increased colony size of Pipistrellus pygmaeus and decreased energy requirements due to thermoregulation. Furthermore, during the period in which the colony is in the reproductive phase there is a greater amount of wetlands within 2 km. This was also noted by Davidson-Watts and Jones as most likely not random but deliberate. Most bats in a colony used one roost site throughout the period from April to October, most likely due to the need to be close to wetland habitats to acquire their specialized diet.
P. pygmaeus feeds on insects, particularly chironomids and other aquatic insects, caught in flight near bodies of water.
Predatory activity begins 20 minutes after sunset, earlier during the warmest and most humid nights. The flight is agile, fluctuating and erratic and is carried out 5-10 meters above the ground.
As regards its conservation status, the IUCN Red List, considering its vast range and abundance, classifies P. pygmaeus as a species of minimal risk (Least Concern).

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Gordon Corbet, Denys Ovenden, 2012. Guide to the mammals of Europe. Franco Muzzio Editore.
– John Woodward, Kim Dennis-Bryan, 2018. The great encyclopedia of animals. Gribaudo Publisher.

Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/340987956/original.jpg