Two species of bed bug occur in Australia, Cimex lectularis and Cimex hemipterus. Bed bugs are relatively small insects, about 5 mm in size. The body is dorsoventrally (from back to front) flattened and they have no wings. They have obvious eyes and sucking mouthparts, and are reddish brown in colour. Bed bugs are blood feeders and are most active at night or in the early hours before dawn, but if starved for some time they may be active during the day.
To obtain a blood meal the bed bug pierces the skin of the host and injects saliva. This saliva has anticoagulant properties which makes the blood flow more easily. Bed bugs ingest their meal rapidly only taking 5-10 minutes to engorge themselves. A blood meal is required at each of the five stages of nymphal development. Female bed bugs lay several eggs in small batches, which hatch in about 10 days. Adult bed bugs can live for approximately 6-12 months. Because of their size bed bugs can get into small cracks and crevices.
Reactions to bed bug bites can vary from no reaction at all to severe irritation and localised swelling at the bite site.
Spiders are arachnids not insects, but both spiders and insects belong to the largest group of animals on Earth, the arthropods (Ancient Greek: arthro = joint, podos = footed) – animals with hard external skeletons and jointed limbs .