Volume 1

Report of the Committee on Bed-Bug Infestation : 1935-1940.

Date:
1942
Catalogue details

Licence: Public Domain Mark

Credit: Report of the Committee on Bed-Bug Infestation : 1935-1940. Source: Wellcome Collection.

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    GENERAL SUMMARY AND CONCLUSIONS (For earlier knowledge on the subject reference should be made to the © *“ Report on the Bed-Bug’”’ prepared by a departmental committee of the - Ministry of Health and published in 1934 (Reports on Public Health and Medical Subjects, No. 72, H.M. Stationery Office, London). Section I (Buxton & JOHNSON) :— 1. Provided a source of blood is available, temperature is the most important factor in the bed-bug’s environment. At the end of winter, the bug population in an unheated room will consist mainly of adults and large nymphs; there will be few small nymphs and a large proportion of the adult females will be unfertile. It is unlikely that many bugs will feed until the temperature rises to 16° C., in the middle of May. They may be supposed to feed, on the average, once a fortnight in the early summer, once a week in August, and then once a fortnight in September and October; after that feeding ceases, owing to the low temperature. 2. From the temperature and the number of feeds the production of eggs by a given bed-bug population may be calculated. The first egg will be laid in the latter part of May, and the production rises to a peak in August. The first adults of the next generation are not mature until the second week in August ; the number attaining maturity reaches a peak early in October, and thereafter rapidly declines owing to falling temperature. 3. In November, when feeding and egg-laying have ceased in an unheated room, there will be large numbers of nymphs and adults, of generations F, and F, together. Nearly all the small nymphs, however, will die of starvation during the winter, and calculations indicate that the natural winter mortality in the bug population may be as high as 80 per cent. This emphasises the practical desirability of concentrating on the destruction of bugs at the end of winter and in early spring, when the numbers are lowest ; at that time of year there are no live eggs (which are more resistant to some fumigants than are nymphs and adults). 4. The conditions described above are modified in centrally-heated flats or in warmed living rooms. While even here a considerable winter mortality among eggs is probable, fasting bugs could survive very well and some feeding might occur throughout the year. It follows that the bug population in warmed rooms tends to increase enormously from year to year. 5. Besides the egg there are five nymphal stages of the bed-bug, the fifth and last moulting into the adult. An individual in each stage must take one full meal of blood before it can pass into the next stage. The rate of development depends both upon environmental temperature and upon accessibility of host. 6. Environmental temperature has an important influence upon the activity of bugs—the higher the temperature of a summer night, the greater the numbers active. Slight fluctuations of temperature have a marked effect on activity. The threshold of activity may be as low as 7° to 10° C. 7. A temperature of 13-14° C. is most favourable to long life of the bugs without food; both above and below this level life is materially shorter at comparable humidities ; for long life humidity must be high, so as to prevent loss of water by evaporation. Adult virgin females and mated males live the longest. The period of survival of fasting adults may exceed one year under climatic conditions close to the optimum. At 13° C. eggs develop and hatch, the mean period being 49 days; they develop very slowly at temperatures even as low as 4° C., but they are unlikely
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