Blaptica dubia (Blattodea, Blaberidae): Damage to photographs

Abstract: Insects, micro-organisms and rodents can degrade cultural heritage kept in museums,archives and libraries by provoking aesthetic and structural damage of various kinds and degrees.Damage to cultural heritage caused by insects varies greatly depending on the kind of pestresponsible, to the extent that, in some cases, by examining the type of degradation and tell-talesigns left by the causative organism, it is possible to identify the kind of insect species involved.Photographic patrimony is a category of heritage that only for the last ten years or so has beensubject to the norms which govern the management and safeguarding of cultural heritage. In thisstudy, cockroaches (Blattodea), which figure among the insects considered particularly harmfulto photographic patrimony, have been investigated. These omnivorous insects, which are quitewidely distributed in museum environments, and above all in archives, can provoke public healthproblems such as allergies, and sometimes even transmit infectious diseases to cultural heritagepersonnel, in addition to damaging heritage.In this paper, we present the results of a study carried out to investigate the damage causedby Blaptica dubia, a cockroach belonging to the Blaberidae family, to sacrificable samples ofphotographic prints of various kinds, drawn from a range of historical periods, including:albumen photographic paper; black and white gelatin silver bromide photographic paper; gelatinsilver chloride photographic paper – Velox black and white; non-resin coated gelatin colourprocess photographic paper and resin coated gelatin colour process photographic paper. Thesample photographs were exposed to live specimens of Blaptica dubia and monitored for a periodof four weeks. The results obtained demonstrated various degrees of palatability among thephotographic materials tested, and confirmed that Blattoids represent a serious cause ofbiodeterioration to photographic heritage, since they are able to cause serious erosion of materialsand their excrement and/or regurgitations leave damaging and unsightly stains.Beyond seeking to assess types of damage and the length of time needed for them to becaused, our experiments were aimed at carrying out a preliminary investigation in order toidentify the materials that are the most palatable to these insects, and hence the photographicsupports which are most vulnerable to this kind of degradation.