Tuesday, August 13, 2013

The Story of Bed Bugs – Biology and Behaviour, Implications for Control


Breeding
  • Females can lay 200 eggs a year
  • Eggs hatch as nymph (tiny versions of adults) just visible to naked eye
  • 5 nymph stages (instars)
  • Need blood feed to move to next stage (instar)
  • Adults – size of apple pip
  • Only adults are sexually mature
  • Cycle as short as 5-6 weeks
Bed bugs can breed quickly. One pregnant adult can become thousands of biting nymphs and adults in a few months.
Early control, when numbers are low, is easiest. Development through many nymphal stages gives opportunity to break life cycle – Insect Growth Regulator (IGR) such as pyriproxyfen stops nymphs being able to moult and grown new chitin skin.

Hiding places
  • Flat body shape to fit in narrow spaces.
  • Cracks, crevices, seams, voids, skirting, under carpet edges, electric sockets, furniture, curtains, ………..
  • …..and, of course the bed.
  • High and low.
  • Usually within 5 metres of bed.
  • Adjacent rooms.
  • Smell when heavy infestation.
Hard to find. Need to be VERY thorough. Treat all possible hiding places, not just where insects are found. Spray with long lasting spray containing insecticide to kill adults and nymphs and IGR to break life cycle. Fumigator to get to places that are hard to find/treat.

Feeding habits and bites
  • Blood suckers – hypodermic proboscis
  • Feed on people and pets
  • Feed at night (usually ~2am)
  • Inject proteins - anaesthetic and anti-coagulant- don’t feel bite and to stop blood blocking proboscis
  • These proteins cause allergic reactions in some people (not all) causing red itchy swelling.
  • Bites are often made in a straight line as bug walks across skin.
  • Ankles, wrists, torso, legs and arms are most common bite sites.
  • Fill up like balloon with blood – flat translucent to round and dark red
  • Small drop of blood on end of proboscis leaves +like mark on bed linen.
  • Excreta like tick made with black Biro.
  • One feed can be enough to keep bug alive for months
  • No evidence of causing disease but very unpleasant
  • Not all bites or skin reactions are caused by bed bugs or other biting insects. Other environmental factors can cause similar reactions. Even thinking about fleas and bed bugs tends to cause psychological feeling of itchiness, scratching and skin reactions.
Treatment must be long lasting and continue past last sighting. No bites (reactions) may not mean no bed bugs.
Bed bug infestations can only be confirmed by finding bed bugs.

Spread
  • Bed bugs do not fly
  • Bed bugs will not crawl far from the bed of their host
  • May choose luggage, boxes, furniture etc. as hiding places and are carried with these items from place to place.
  • Increased world travel has made them more common again
  • Numbers dropped dramatically when powerful insecticides used (e.g. DDT). Now the powerful insecticides are banned so numbers have grown.
Travel and moving hose are common ways for bed bugs to spread. Treat luggage before travel. Check accommodation for evidence of bed bugs before staying.
Kiwicare products work but more effort is required than when using the like of DDT.

Species
  • Just one that causes problems for people. - Cimex lectularius
  • Other species specific to other animals e.g. bat bed bugs
Safe products
  • US EPA approve product ingredients for use in bedrooms
  • Include permethin and pyriproxyfen in NO Bed Bugs and cyphenothin in NO Bugs Borafume.
Kiwicare NO Bed Bugs Box is safe to use in bedrooms. Can be used on beds but recommend only underside and seams of mattresses. Do not use on bed linen.
Bed linen and clothes can be put in hot wash, tumble dried on high heat or placed in freezer (24hrs) to kill bugs and eggs.

Have you heard about the lady pregnant bed bug? She gave birth in the spring.

1 comment:

  1. We were literally worried of the tiny little bed bugs, as they kept biting all night, so we had to call the pest exterminators at Pretoria. It was definitely a fair decision, as our beds are clean again, and we do not have to spend the sleepless nights.

    ReplyDelete

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