Common insect pests in homes and cultural heritage sites

Bostrichidae

The lesser grain borer (Rhyzopertha dominica) belongs to the Bostrichidae family, which includes over 700 species, many of them wood borers. Some bostrichid beetles, including the lesser grain borer, can reduce bamboo and sapwood timber to a powdery frass. This causes significant economic losses in the forestry and lumber industries. The larvae typically inhabit the sapwood and cambium of dead, injured, or newly cut and stored branches and trunks, facilitating the spread of invasive species across countries. In many parts of the world, particularly tropical and subtropical regions, Rhyzopertha dominica is also a major pest of grain crops. This cosmopolitan, polyphagous insect pest can cause huge economic losses in stored goods (Edde, 2012; Ortega et al., 2021; Shah et al., 2021). This species has been found in botanical remains kept in the Museum of Liverpool in the UK (Panagiotakopulu, 1998).

Powderpost beetles are named after the effect that these bostrichid beetle larvae and adults can have on bamboo and sapwood timber, often turning it into powdery frass. As a result, the forestry industry and lumber-dependent businesses have experienced enormous economic losses (Liu, Leavengood & Bernal, 2022). Like the lesser grain borer, powderpost larvae live in the sapwood and cambium of dead, injured, or newly cut and stored branches and trunks, which has aided the spread of foreign species from one country to another (Toriti, Durand & Fohrer, 2021).

The most common pest species, Dinoderus minutus, has a worldwide spread, poses a danger to maize crops, and attacks bamboo-based structures and structures. Breeding sites include rattan goods and wooden container crates (Liu, Leavengood & Bernal, 2022; Majka, 2007).

Lyctus linearis and Lyctus brunneus are worldwide xylophagous beetles that attack wood. They damage furniture, woodwork, and other materials. The French entomologist Pierre Lesne first discovered these species in a collection of museum woodwork during his research (Lesne, 1922, 1910).

Another significant species that damages furniture is Bostrichus capucinus, which can pierce lead plates with their powerful mandibles (Toriti, Durand & Fohrer, 2021).

Cerambycidae (longhorn beetles or Capricorn beetles)

According to the literature, the family Cerambycidae (longhorn beetles) or Capricorn beetles includes some of the world’s most destructive xylophagous species (Brockerhoff et al., 2006). From an economic standpoint, it is one of the largest groups of insects in the world, affecting forests, timber products, shade trees, and fruit and nut trees (Kariyanna, Mohan & Gupta, 2017). Most damage occurs in the larval stages and affects both softwoods and hardwoods (Raje et al., 2012). Hylotrupes bajulus is one of the principal species in this family and is thought to be responsible for significant economic losses in wood and wood products (Yalcin et al., 2020). This species poses a threat to historical items, attacking any wooden furniture including antique clocks and carved wooden furniture, and it has been demonstrated that it prefers wood kept in long-term storage (Kariyanna, Mohan & Gupta, 2017; Yalcin et al., 2020).

Silvanidae (saw-toothed beetle)

Oryzaephilus surinamensis is a serious pest affecting stored goods (Vendl, Stejskal & Aulicky, 2019) and is an invader of packaged consumer foods worldwide. It enters through improperly sealed openings or tears in packaging and has a significant negative economic impact (Gharsan et al., 2018, 2022). It is considered a very serious devastator, as it poses a threat to dates and other dried fruits (Hashem, Khalifa & Ahmed, 2021). Its rapid reproduction and profusion can cause it to invade many healthy spaces, such as packaging and empty stored bottles, leading to their presence when these are filled (Fig. 2).

Curculionidae (weevils)

This family includes the most destructive tree-killing bark beetles in Europe, including Scolytus multistriatus, Scolytus rugulosus, and Ips typographus. Beetles from the Cossoninae subfamily are a specialist group that generally develops in fresh to rotting wood. Other species include Amaurorhinus brewickianus, Pselactus spadix and Pseudophloeophagus truncorum (Liotta, 2015; Skuhrovec, Hlaváč & Batelka, 2017). Through their feeding activities, these species were responsible for the separation of certain artefact components on display at the museum, causing significant ecological and economic damage (Powell et al., 2021; Jeger et al., 2017; Tanin, Kandasamy & Krokene, 2021).

The most destructive and widespread species, Pentarthrum huttoni, is found in historic buildings and human dwellings. It was first discovered in Austria and was responsible for the irreversible disintegration of 18^th century wooden coffins (Halmschlager et al., 2007; Domenico, 2012). Hexarthrum exiguum has been identified as a harmful species which originates from the external environment and infests historical goods made of wood (Ungurean, 2012). It is known as the “pit-prop beetle” in Central Europe because it damages wet wood, primarily in mines but also in homes (Cebeci, Hellrigl & Whitehead, 2011). Species such as Sitophilus granarius, Sitophilus oryzae, and Sitophilus zeamais colonise and destroy grain, and inflict significant losses on a global scale (Hagstrum, 2017). Sitophilus granarius is the most frequently discovered species in archaeological contexts and may be found in settings ranging from tiny rural warehouses to huge storage silos (Lemic et al., 2020; Pécréaux, 2008).

Ptinidae

The Ptinidae family includes both xylophagous insects, which feed on wood, and polyphagous insects that are pests of stored goods (Toriti, Durand & Fohrer, 2021). Many species previously classified in the Anobiidae family are now included in the Ptinidae family. Some larvae contribute to the deterioration of organic plant and animal matter, with certain species consuming dry excrement or feeding on animal corpses. For instance, Ptinus sexpunctatus, Ptinus pyrenaeus, and Ptinus tectus can be found in the nests of social hymenopterans, where they feed on exuviae and organic waste.

Some species of Ptinidae larvae lead to the deterioration of organic plant and animal matter. While some species consume dry excrement, others feed on animal corpses. Ptinus sexpunctatus, Ptinus pyrenaeus, and Ptinus tectus are examples of larvae that can be found in the nests of social hymenopterans, where they feed on their exuviae and organic waste (Calmont, 2016).

In 1941, the Department of Entomology at the British Museum highlighted 21 species of Ptinidae identified as pests. The majority of them destroy stored goods of all kinds and belong to two sub-families, Gibbinae and Ptininae, represented in the table below (Hinton, 1941). Woodborers such as Anobium punctatum (Coleoptera: Ptinidae, formerly Anobiidae), a widespread species, were common in furniture and historic buildings in the past, but with the rise of modern housing, they are now frequently found in museums and historic buildings. Wood-boring beetles have been found in wooden shipping crates and wooden pallets used to transport and protect works of art, which has resulted in these works becoming infested with these pests and contaminating museums (Fig. 3). Three cases of infestations of newly manufactured picture frames in Austria between 2010 and 2015 and wooden pallets were all associated with the spread of various wood-boring beetles (Child & Pinniger, 2014; Wang, 2021; Biebl & Querner, 2021). This pest is responsible for significant financial losses due to the irreversibly damage it causes (Paul, Prozell & Schöller, 2007; Auer, Opitz & Kassel, 2021). Xestobium rufovillosum, known as the death-watch beetle, is the largest species in terms of size. The larvae prefer aged oak timber rather than softwood and can damage wooden objects in museums and libraries if exposed to fungal decay (Campbell & Bryant, 1940; Crous et al., 2020; Campbell, 1941; Toriti, Durand & Fohrer, 2022). Infestation is favoured when humidity is high. In humid environments, fungus can soften the wood, which allows insect larvae to more easily tunnel through the wood while feeding on cellulose and hemicellulose (Richards & Brimblecombe, 2022). Oligomerus ptilinoides, a species of beetle belonging to the Anobiidae family and native to the Mediterranean region, is renowned for its destructive impact on wood in some southern European countries (Fig. 4). It is particularly notorious for the extensive damage it inflicts on objects made from hardwood, such as furniture and works of art (Halperin, 1992).

Recently, Gibbium psylloides, which belongs to the Ptinidae family, was identified during a survey to determine the biodiversity of insect pests that infest the manuscript library of the Coptic Museum in Egypt (Abu El-Hassan et al., 2021). Lasioderma serricorne (a polyphagous insect), known as the “cigarette beetle”, is a serious pest of museums, books, and dried plants, in addition to being a pest of tobacco storage. Because of the harm it can do to dried herbarium specimens, this beetle is known as the “herbarium beetle” in hotter countries (Edde, 2019; Guarino et al., 2021). Among the polyphagous insects, Mezium affine is known as the “spider beetle” because of its round body shape. The larvae feed on dried meat, dried mushrooms, seeds, wool, hair, feathers, leather, book bindings, insect collections, books, and all kinds of dried animal and plant specimens, leading to their classification among the insects that threaten museums (Dogruer, 2022). Nicobium castaneum poses a threat to all types of wood products, including composite wood, and typically destroys historical artefacts, eating old documents as well as every kind of paper, cardboard, parchment, and leather (Shah et al., 2021). Stegobium paniceum (a polyphagous insect), is known as the “drugstore beetle” and damages dry plants, paper pulp, and starch-rich cardboard. It usually feeds on the bindings of old books that have been coated with starch glue, leaving tunnels (Cao et al., 2022; Abdelghany et al., 2010; Shah et al., 2021).

Dermestidae (hide and carpet beetles)

The term “dermestid” comes from the Greek term “dermestes”, meaning “skin-eater”. This family contains over 1,800 named species (Busvine, 2013). Certain species within this family are of significant economic and cultural concern due to their pest-like behaviour, as they can spread easily through global trade (Querner et al., 2013; Bradshaw et al., 2016). These beetles are found in a variety of biological settings, including human residences, animal carcasses, and bird and spider nests. Recently, they have become prevalent pests in the rapidly growing pet food sector in many wealthy countries (Zeng et al., 2021). Among the species of this family that are considered as pests of historic buildings and homes, are species from the genera Anthrenus, the larvae of which are harmful to different commodities of natural origin. Species from the genera Anthrenus, include Anthrenus flavipes, also known as the “carpet beetle”, a common pest that can cause damage to museums and households (Hava, 2022; Kumar et al., 2013). It damages textiles, clothing, and items made of animal origin, such as wool, fur, feathers, and hide, in addition to carpets (Kumar et al., 2013). Anthrenus verbasci is a cosmopolitan species known as the “museum beetle” and has been detected on old books and ethnographic textiles (Fig. 5) (Pradhan, 1948; Antonie & Teodorescu, 2009; Peace et al., 2022). Also known as the “varied carpet beetle”, it infests items such as carpets, woollen materials, silks, hides, furs, feathers, hair, horn, cereals, red peppers, fishmeal, and any processed animal or plant food. In common with other carpet beetles, this species will feed on cotton, linen, and synthetic fibres if they are contaminated with human excretions (blood, skin, hair) (Faheem & Abduraheem, 2019). Most species of the genera Attagenus spread through infested bird nests, rodent carcasses, and dead birds (Querner, 2015), such as Attagenus pellio, known as the “two-spot carpet beetle” (Bergmann-Hug, Furrer & Helbling, 2007). Other significant pests of organic artefacts in European museums are Attagenus smirnovi, also known as “vodka beetles” or “carpet beetles” (Fig. 6) (Hansen et al., 2012; Schmidt et al., 2023). Attagenus unicolor, known as the “black carpet beetle” is a household pest unique in its ability to digest complex proteins, and is widely recognised as a serious economic pest threatening stored products and museum collections (Keefe & Lei, 2021; Zhou et al., 2022).

Species from the Dermestes genus (Coleoptera: Dermestidae) can be serious pests threatening stored animal products, such as food, silkworm cocoons, leather and other textile items, and museum collections. Both the adult and larval stages are scavengers that favour dry, protein-rich organic matter (Gharsan et al., 2022; Martín-Vega et al., 2017; Kadej et al., 2022). The genus includes species that are of forensic interest, such as Dermestes haemorrhoidalis, Dermestes ater, Dermestes frischii, and Dermestes lardarius (Kadej et al., 2022; Magni et al., 2015; Charabidze et al., 2014).

The Trogoderma genus, containing approximately 130 described species is widely distributed (Castalanelli et al., 2012). Among these species is the khapra beetle, Trogoderma granarium, which originated from India (Busvine, 2013). This species is extremely destructive and is classified as a quarantine pest in the United States. Another significant pest in this genus is the warehouse beetle (Trogoderma variabile), a common and destructive insect found in stored products. It is highly fertile, a strong flyer, and often found in processing facilities and storage warehouses. (Gerken et al., 2021) Additionally, Trogoderma angustum is a notable pest of museums and historic houses. Its larvae are exceptionally polyphagous and are capable of developing on a wide range of plant, grain, and animal-based products (Holloway & Sparks, 2023).

Biology of coleopotera

The biology of beetles is diverse, due to the high number of species, although there are many common characteristics. Anatomically adult beetles (Coleoptera) have four stiffened wings known as “elytra” covering the abdomen and separating them from other insects (Noh et al., 2016). For some families, such as blister and false blister beetles, the body and elytra are soft. The head contains the mouthparts that are adapted for biting or chewing (Busvine, 2013). There are four stages in the lifecycle of beetles, and complete metamorphosis begins with the egg, and moves through the larval and pupal stages before finally becoming, adults (Mullen & Durden, 2018).

Eggs are placed individually or in clusters on or in soil, living or dead plant debris, textiles, water, carrion, and, in rare cases, living animals. They hatch as vigorous larvae containing simple eyes (ocelli) and chewing, mandibulate mouthparts, and an abdomen segmented into between eight and ten parts. Most beetle larvae moult at least three times before becoming pupae (Eldridge & Edman, 2012). Beetle larvae are often responsible for the most damage to different materials (Mullen & Durden, 2018).

In the UK, for example, adult Anobium punctatum beetles emerge between April and July and survive for 20–30 days. Females deposit their eggs in rough wood, end grain, cracks and crevices, as well as old flight holes. The eggs hatch within 15–25 days. Excreta (frass) is abundant in the larval tunnels, and has a gritty texture and barley-grain form. When the larvae are fully developed, the pupal chamber expands. After 2 to 3 weeks, depending on the family to which it belongs, the adults emerge, leaving a distinctive circular exit hole in the case of Ptinidae family and an oval-shaped hole in the case of the Cerambycidae family (Child & Pinniger, 2014).

Damage to and impact on human health

In addition to the significant economic losses that affect a wide range of products, buildings and industry (Hasan et al., 2007; Shah et al., 2021; Jung et al., 2020), these pests also affect human health. Coleoptera do not threaten human life, but some beetle species may have an impact on human health, such as the beetles of genera Anthrenus, Attagenus, Dermestes, and Trogoderma known as “carpet beetles” which can cause a cutaneous pruritic papulovesicular reaction due to the hairs (hastae) on the larval surface, which can lead to an allergic effect (Gumina & Yan, 2021; Ahmed et al., 1981). In Malaysia, a case of Canthariasis intoxication of a 1-year-old infant was thought to be due to Lasioderma serricorne larvae (Mokhtar et al., 2016). The dermestid beetle is known to infest human remains and can cause damage to bones and tissue (Kadej et al., 2022). Other cases of allergies in wool workers and museum staff have been reported as being caused by dermestid beetles (Bergmann-Hug, Furrer & Helbling, 2007). One study has shown that Dermestids can produce chemical allergens (Zeng et al., 2021). Moreover, beetles such as Anobium punctatum play host to Pyemotes ventricosus mites, small arthropods that are tissue-juice feeders responsible for intensely pruritic erythematous maculopapular lesions with central micropustules (Neumayr & Kuenzli, 2019; Hanks et al., 1992; Darles et al., 2013; Giudice et al., 2008). Where the volume of Pyemotes exceeds the available supply of food, they have been known to occasionally bite mammals, including humans, causing dermatitis followed by a “comet sign” lymphangitis, as in the case of one Caucasian woman (Laghi et al., 2021; Berenger & Parola, 2023).

Some research suggests the possibility of isolating probiotic bacteria from the faeces of storage food insects such as Tribolium castaneum, and using it as a model system for screening (Grau, Vilcinskas & Joop, 2017).

Beetles can have a profound impact on human food supplies. One of the major concerns about them is their ability to attack grain reserves, leading to potential famine, particularly in communities which are heavily dependent on grains as their main source of sustenance (Fornari et al., 2013; Yardim et al., 2006; Leidemer et al., 2022). When they infest stored grains, they consume and contaminate the food, resulting in substantial crop losses and reducing the food available for human consumption. Moreover, the damage caused by beetles can compromise the quality and nutritional value of the grains, making them unsuitable for human consumption even if they are not entirely consumed (Stathas et al., 2023).

Biology of Blattodea

Termites and cockroaches are both part of the same order of insects known as Blattodea. While they may look very different on the surface, they share many similarities in terms of their biology and behaviour (Lihoreau, Costa & Rivault, 2012), both being hemimetabolous insects (Inward, Beccaloni & Eggleton, 2007). Their development cycle consists of several stages, including the egg, nymph, and adult stages. Females are ovoviviparous (McGavin, Davranoglou & Lewington, 2023).

Cockroaches have a varied diet and are omnivorous scavengers, eating many organic decaying materials, such as birds. Most species have smooth, flattened bodies that enable them to fit into small spaces, and they tend to live in crevices (McGavin, Davranoglou & Lewington, 2023). After adult cockroaches mate, the female lays an average of between five and 40 eggs, depending on the species of cockroach. The eggs are covered with an ootheca, a protective egg case (Rust & Su, 2012). The female deposits the case in a secret location and uses her saliva to adhere it to a surface. Within a month, immature cockroaches emerge in warm environments. Cockroach juveniles moult between seven and eight times before they reach adulthood (Perrott & Miller, 2010; Guthrie & Tindall, 1968; Tanaka & Uemura, 1996). The time for a nymph to reach the adult stage depends on the species, with an average of between 126 and 365 days, when all the conditions for development are met (Gondhalekar et al., 2021).

Both nymph and adult cockroaches have a mouth part containing strong toothed mandibles which are well developed for biting and chewing. In most cases, the adults have two pair of wings known as the “tegmina” (Eldridge & Edman, 2012).

Termite development includes an incomplete metamorphosis within castes, including nymphs, pseudergates, workers, soldiers, and several types of reproductive termites. Before becoming productive workers, nymphs hatch from eggs and moult at least three times (Resh & Carde, 2009; Bouillon & Mathot, 1965; Lauff, 2004).

Damage to and impact on human health

Termites and cockroaches are related to each other within the Blattodea order. Many species are among the top decomposers of dead wood and pests on the planet. They are valued for their ecological and economic contributions both locally and internationally. They are crucial to the health of many ecosystems, and the decomposition of dead wood has measurable effects on the climate (Inward, Beccaloni & Eggleton, 2007; Evangelista et al., 2019).

Less than one percent of cockroaches species are regarded as pests (Noda et al., 2020), because of their invasive behaviour toward homes, buildings, and other environments, infesting food, clothing, and the surfaces they crawl on. According to recent research, it is believed that cockroaches and humans started living together when people began building dwellings (Obata, Sano & Nishizono, 2022). Their presence can have a significant economic impact on properties and communities. While the exact financial cost of these infestations is difficult to assess, there are several ways in which they can affect property values and local economies (Brune & Dietrich, 2015).

Cockroaches may be implicated in the spread of nosocomial infections, which are the main causes of morbidity in immunocompromised patients (Colombo & Guimarães, 2003; Fotedar & Banerjee, 1992). Several recent studies have demonstrated the capacity of cockroaches to transmit fungi such as Candida spp., Aspergillus spp. (Lemos et al., 2006; Nasirian, 2017), and bacteria including Salmonella, E. coli, Klebsiella, Pseudomonas, Staphylococcus, Enterobacter, Streptococcus, Serratia, Bacillus, and Proteus (Fakoorziba et al., 2010; Kassiri, Kasiri & Quaderi, 2014; Kassiri, Kassiri & Kazemi, 2014; Sharawi, 2023). In the 1950s, one research study indicated the correlation between cockroach infestations and hepatitis A (Kapelinskaya et al., 2011; Tarshis, 1962). Intestinal protozoa and helminth parasites such as Entamoeba coli and Entamoeba histolytica/dispar cysts, as well as Enterobius vermicularis, Trichuris trichiura, Taenia spp, and Ascaris lumbri coidesova cysts were isolated in 2008 in both the bodies and guts of the Blattella germanica, Periplaneta brunnea and Pycnoscelus surinamensis cockroach species (Kinfu & Erko, 2008). Another study showed that the presence of protozoa Blastocystis homnisis was responsible for digestive symptoms in the Periplaneta americana cockroach species (Zaman et al., 1993). Other experimental studies have demonstrated the vectorial potential of cockroaches. Finally, cockroach infestations can cause psychological issues (Porusia, Ratni & Dhesi, 2020; Roth & Willis, 1960).

Many other medically relevant pathogenic agents have been isolated in cockroaches from their body surfaces and in their excrement, in infectious environments such as homes, hospitals, and industrial settings (Hashemi-Aghdam & Oshaghi, 2015; Fakoorziba et al., 2010; Kassiri, Zarrin & Veys-Behbahani, 2018). In 1964, cockroaches were linked for the first time to allergic reactions (Bernton & Brown, 1964; Bell & Adiyodi, 1982). Cockroach infestations may cause asthma, rhinitis, eczema and other allergic diseases, especially given that they are a source of inhalant allergens (Jiang et al., 2008; Do, Zhao & Gao, 2016; Sohn & Kim, 2012).

Termites represent the most troublesome pests for both plants and buildings, and are responsible for more than US $40 billion in economic losses every year (Rust & Su, 2012). People in the United States spend more than US $11 billion each year on preventing, treating and repairing termite damage (Janowiecki et al., 2021). However, although termites cause enormous economic losses, they also perform work as ecosystem engineers, influencing the distribution and aggregation of phosphorus in the soil and increasing water infiltration (Hasnaoui et al., 2022; Lin et al., 2024). Studies have shown that termites are highly rich in proteins, vitamins, and calories and their use in the medical field has been reported to treat various diseases such as asthma and bronchitis. Other investigations have found that water extract of termite might reduce HIV-1 viral activity (Zhang et al., 2023).

Biology of lepidoptera

Adult females lay their eggs separately or in groups, attached to the surface with an adhesive (Trematerra & Fontana, 1996). At around 10 days, the eggs hatch and larvae emerge. There are usually five or six larval instars which develop into the pupae stage. The larval stage can last for 30 months, moderated by the environment conditions (food, temperature, humidity) (Cox & Pinniger, 2007). The larvae stop feeding and usually spin a tough, spindle-shaped, silken cocoon in which they pupate. Adults lack functional mouthparts, their purpose being to reproduce and lay eggs (Medha et al., 2021).

Damage to and impact on human health

Moths are responsible for serious and irreversible damage to fabric, furnishings, textiles, artworks, and other manufactured items involving materials of both animal and plant origin. One study has shown that damage caused by cloth moths is more serious than that caused by beetles (Bry, 1991; Schwabe et al., 2021). The damage can affect stored products, domestic items, and museum artefacts (Querner, 2016). Moth species have been reported to infest stored animal products, and losses of up to 50% of product yields have been reported (Rajendran & Hajira Parveen, 2005).

Many museum pests were reported to have destroyed artefacts made of wood, fabric, fur, feathers, felt, and other animal or plant materials at three major museums in Vienna. The pests included the Tineola bisselliella moth, which has been classed as a species of museum pest (Querner, 2009). According to the literature, the larvae of the brown house moth Hofmannophila pseudospretella occasionally eat the glue from moist books, which causes the condition of the books to deteriorate (Pinniger & Lauder, 2018).

Unlike some other insects, species in the Lepidoptera order do not generally have a direct impact on human health. However, it has previously been shown that insects such as moths and butterflies can exacerbate the symptoms of bronchial asthma. This has been proven in asthmatic Japanese patients, where immunology exams showed the presence of antibodies against midges and moths (Komase et al., 1997). Other cases have reported allergic skin and respiratory reactions caused by bee moths (Asero et al., 2008).

Damage to and impact on human health

Silverfish are seen by homeowners as a nuisance and may have an indirect impact on human life, in both the economic and medical fields (Barletta, Felice & Pini, 2007; Savoldelli et al., 2021), Researchers conducted a study of insect abundance using traps placed in various museums during the COVID-19 pandemic in Vienna. The results showed an increase in the number of common silverfish (Lepisma saccharina), as well as the long-tailed silverfish (Ctenolepisma longicaudatum and Ctenolepisma calva) in some museums. Although other insects were also found, their numbers did not increase significantly over the same period (Brimblecombe, Pachler & Querner, 2021). Research has shown that household dust harbours substantial levels of antigens originating from silverfish. In the early 21^st century, one study suggested that silverfish could be a significant source of indoor inhalant allergens. Scientists subsequently isolated a specific component, rLet s 1, from silverfish and demonstrated its ability to trigger allergic reactions in patients (Barletta et al., 2002). These hypersensitivity reactions occurred through various routes of exposure, including inhalation, ingestion, and parenteral administration (Barletta et al., 2005). Based on these results, further research demonstrated IgE sensitisation to Lepisma saccharina (common silverfish) in children with respiratory allergies. The study revealed a high frequency of IgE binding to specific proteins in the silverfish extract.

Biology of Psocoptera

Psocids have a tropism to wet areas. A temperature of 22 °C to 33 °C, with 70% to 80% relative humidity, is ideal for their growth and multiplication. While a low temperature of 2 °C is undesirable for adult survival, the eggs may survive and hatch as soon as temperature and humidity conditions become favourable (Pinniger & Lauder, 2018; Rees & Rangsi, 2004).

Psocids exhibit a variety of reproductive patterns, with females depositing between 50 and 100 eggs during their lifetime. However, some psocids, such as Archipsocopsis and Phallocaecilius, are viviparous. Eggs can be deposited alone or in clusters and the entire embryonic development takes place within the mother’s ovary (Cano & Cano Ortiz, 2012; Gavrilov-Zimin, 2021).

Typically, nymphal development covers six nymphal instars before reaching adulthood. Egg hatching takes between 1 and 4 weeks, and a nymph emerges in the first stage of development. The psocids have no pupal stage and are the number of stages is occasionally reduced to five, four, or even three. Under optimum conditions, the pest’s life cycle is completed in 21 days (Mockford, 1993).

Parthenogenesis is known to occur in about 15 families of the three Psocoptera suborders (Mockford, 1971). The literature reveals that psocid infestations increase in warmer climates, a fact demonstrated by the installation of 30,000 insect traps in English heritage properties (Brimblecombe & Brimblecombe, 2015).

Damage to and impact on human health: allergies and Rickettsia

The economic impact of psocids on stored products has been estimated as weight loss of between 5% and 10% (Nayak et al., 2014). Psocids, like other insects, have been linked to cases of dust allergies in humans (Turner et al., 1996). There is no evidence in the scientific literature of their role as pathogen vectors. However, many studies have demonstrated the presence of Rickettsia and suggest that they play a role in the early development of the oocyte (Škaljac, 2012; Clemmons & Taylor, 2016). Others have suggested that Rickettsia is an obligate symbiont of L. bostrychophila (Yang et al., 2015, 2013; Li et al., 2011).

Their existence in household dust and museums exacerbates symptoms of dust allergies (conjunctivitis, rhinitis, and dermatitis) (Patil, Niphadkar & Bapat, 2001; Ishibashi et al., 2017; Gautam, Opit & Shakya, 2016; Gautam, Opit & Giles, 2010). This was demonstrated in the description of a patient who began working at an antique bookstore (Veraldi, Brena & Süss, 2019) and developed an allergy.