Identification and Spread of the Ghost Silverfish (Ctenolepisma calvum) among Museums and Homes in Europe

Insect Distribution in a Vacant Multi-Level Office Building

The webbing clothes moth (Tineola bisselliella) causes extensive and costly damage to fabrics, furnishings, and museum objects. It is best known from its presence in homes, museums, and historic properties, while infestations in office buildings are not as well understood. Offices typically have more frequent cleaning, fewer quiet habitats, less food availability, and fewer breeding environments for moths, which may explain the lower abundance. Nevertheless, they can be introduced with materials or by employees whose homes have a moth infestation. This study examines the distribution of different insect pests determined from pheromone traps set out in an unoccupied multi-floor office building in Switzerland. Tineola bisselliella dominated the insect catch but was mostly found in the aisles on the lower floors. The larger rooms tended to have a greater insect catch. Carpet beetles (Attagenus smirnovi) and silverfish (Zygentoma) were also found, although in smaller numbers, and often preferred the basement floors. The ghost silverfish (Ctenolepisma calvum) dominated the Zygentoma, even though it has been rare until recently in Switzerland. The study suggests the need for Integrated Pest Management within office buildings. In addition, in unoccupied buildings under renovation, with no obvious sources of food, insect pests still need monitoring.

Development and Reproduction of a Japanese Strain of Ctenolepisma calvum (Ritter, 1910) at Room Temperature

Ctenolepisma calvum (Ritter, 1910) (Zygentoma: Lepismatidae) is a primitive wingless insect that causes damage to paper, and it is regarded as a pest of collections in museums, archives, and libraries. This species was recently discovered in Japan for the first time and may have already spread over large areas of Japan, but, currently, no information is available on the biological characteristics of C. calvum in Japan. In this study, we observed the processes of development and reproduction of C. calvum found in Japan at room temperature. Oviposition was observed from April to November, with a peak in early June. The average egg period was 56.9 days at average temperatures above 24.0 °C, and was 72.4 days at average temperatures below 24.0 °C. The 1st, 2nd, and 3rd instars lasted 4.7 days, 13.2 days, and 26.1 days on average, respectively, at average temperatures above 22.0 °C. Average instar periods were 23-28 days in 4th-7th instars and tended to increase in later instars. Instar periods also increased when the average temperature was 22.0 °C or lower. In individual rearing, the longest-living individual lived for approximately two years, up to the 15th instar. The head width grew at an approximate ratio of 1.1 per molt. First oviposition occurred at the 10th or 11th instar. Individually observed females oviposited once or twice a year, laying 6-16 eggs at one time, but females at least two years old laid 78.2 eggs per year on average in a mass-culture cage. Through this study, only females were found, and the mature females produced their progenies parthenogenetically.

New records of Ctenolepismacalvum (Ritter,1910) (Zygentoma, Lepismatidae) from Japan

Background

Silverfish are known as one of the major pests which feed on paper and starch-based materials and can cause serious problems in museums, libraries and archives.Ctenolepismacalvum (Ritter, 1910) was first recorded from Ceylon (now Sri Lanka) and has also been known from Central American countries including Guyana and Cuba. Recently, its rapid spread to European countries, including Austria, Czech, Germany and Norway, has been reported. In addition, there are unverified records of C.calvum from 17 more countries in the on-line citizen-science platforms iNaturalist.

New information

We report C.calvum in Japan for the first time, from Hokkaido, Miyagi, Tokyo, Fukuoka and Nagasaki Prefectures. The specimens in Japan were observed in detail by stereomicroscope, optical microscope and scanning electron microscope. The occurrence of this species is a serious problem from the viewpoint of protection of cultural properties. We also registered their mitochondrial cytochrome oxidase I (COI) gene in EMBL/GenBank/DDBJ.