Insect collections can be seriously damaged or destroyed by dust, biotic pests (insects, moulds, etc.) and climatically unsuitable environments. In addition to this, depository areas with collections should also be secured against intrusion by unauthorised persons and against natural disasters. The set of measures ensuring such protection of the collection is called the depository regime.

Protection against dust

The collection objects (here insect specimens) are protected against dust by storage in sealed entomological boxes and in sealed collection cabinets. Ideally, the boxes should be placed in airtight compactor shelving systems.

Recommendations:

• Use sealed display cases or entomological cabinets with sealed doors (e.g. rubber or felt seals).
• Use filters or cover glass - display cabinets should be made of materials that minimize static electricity (e.g., glass instead of Plexiglas).
• Regular cleaning around the collection, preferably with a damp cloth, not a duster, to keep dust from stirring up.
• Do not display the collection in an open space, e.g. on shelves without a cover.

Protection against biological pests

It is important to protect against harmful insects attacking dry preparations, such as various species of disturbers and skin-eaters (Anthrenus, Attagenus, Dermestes), Tribolium sweat beetles, pantry worms (Stegobium paniceum), some moths and moth moths, pine beetles, etc. If the access of these insects to the depositories cannot be prevented, the collections must be chemically treated regularly. This is the so-called disinfestation, which can be carried out, for example, by aerosol gassing the entire (closed) premises with a mixture of insecticides (it is advisable to change the mixture after a certain period of time) at least once a year, ideally at the time of the greatest pest infestation, i.e. at the turn of April and May. This should be done by a professional company, but for smaller collections it can also be done with smoke bombs (Coopex, Actellic, etc.) or sprays (Detmol, etc.). New acquisitions (acquisitions obtained by own collection or entire purchased collections) must be treated before they are placed in the depository, because of the possibility of introducing pests. New collection materials are best treated by freezing at very low temperatures (below -30°C) or by short-term heating to more than 60°C while lowering the humidity (below 30%), or by gassing with a highly poisonous gas (e.g. phosphine), but such treatment can only be carried out by a professional disinfestation company.

Against moulds, which like to attack the chitinous surface skeleton of insects, it is necessary to keep the relative humidity below 50% at all times, ideally in the range of 30 - 50%. Although prepared insects in collections can tolerate higher relative humidity (up to 80%), the risk of fouling of the slides increases significantly at humidity levels above 50%.

Recommendation:

• Quarantine new specimens by wrapping them in double bags and sealing them in a -20°C/72 h (or -30°C/48 h) freezer for several days before adding them to the collection. Then thaw in closed packaging. The cycle can be repeated if necessary.
• Carry out regular monitoring by setting glue traps in cabinets and in the room. Carry out regular monthly checks and record in a logbook.
• Typical pests: Dermestidae (leatherjackets), Tineola bisselliella (clothes moth), psocids (piscivores), fish moths.
• Use closed and tight enclosures (e.g. entomological cabinets with foam seals).
• Use repellents and preservatives
  • Thymol, Naftalen, paradichlorobenzene or modern substitutes (e.g. ethyl acetate capsules or silica-gel with repellent component).
  • Natural alternatives: lavender, cedarwood (must be renewed regularly).
• Maintain low humidity (up to 50%) to reduce the risk of mould.
• Regularly inspect collections at least 2 - 4 times a year, including visual inspection for signs of infestation.

Protection against adverse climatic conditions

The deposit regime for insect collections requires:

• dryness (low relative humidity between 30 and 50%),
• temperature (between 18 and 25°C),
• avoidance of light.
  Light (both daylight and artificial) irreversibly damages the colouration of many insects (especially non-metallic colours fade), so it is important to keep glazed collection boxes in well-closed cabinets. If insects are on display, it is necessary to limit the time they are exposed to light (i.e. short-term exhibitions only) or to allow them to deteriorate over longer periods (long-term exhibitions, permanent displays).

Recommendation:

• Maintain a stable environment: temperature 18 - 25 °C, relative humidity 30 - 50%, without rapid fluctuations.
• Place Silica gel/Art-Sorb in drawers and cabinets and regenerate it regularly (indicator variant changes colour).
• Do not expose collections to direct light. UV light causes colour fading, artificial lighting with UV filter (≤ 50 - 150 lux) is recommended.
• Ventilate regularly, but without draughts. Keep the collection away from heaters and the sun.
• Limit emissions from wood and glue: line the inside of cabinets with barrier film and archival cardboard.

Recommended routine maintenance schedule

• Weekly: damp wiping of surroundings, brief ventilation without drafts.
  
  
• Monthly: check glue traps + write-up, quick visual inspection (grit, maggots).
  
  
• Quarterly: regeneration of silica gel, verification of gauges.
  
  
• Semi-annually: detailed inspection of all cabinets and drawers, seal test, desinfestation recovery (e.g. thymol).
  
  
• Annually: review of furniture, replenishment of barriers, relabeling of faded labels.

Actions when pests enter our collection

• Insulate infested boxes (place them in PE bags).
  
  
• Freeze infested boxes according to protocol (-20°C/72 h or -30°C/48 h).
  
  
• Clean the infested boxes and check their seals.
  
  
• Increase monitoring of the collection to 6 - 8 weeks.