Читать книгу Honey Bee Medicine for the Veterinary Practitioner - Группа авторов - Страница 53

It should come as no surprise that the honey bee superorganism can mount a biological “fever” as a direct preventative measure against a heat‐sensitive pathogen. This fever is not mounted in the individual bee but rather in the heart of the colony in the developing brood, and is a remarkable example of convergent evolution between the organism and superorganism. In a fascinating experiment, Starks and colleagues (2000) measured brood comb temperatures in three colonies and one control colony in response to changes in ambient environmental temperatures and following the inoculation of an infective dose of the fungal pathogen for chalkbrood disease (A. apis). Chalkbrood is triggered by chilling of the brood; therefore, it is a seasonal condition most prevalent in the spring of the year or in small colonies that are unable to maintain homeostasis by way of thermoregulation. Normal brood comb temperatures are maintained within a very narrow range from 33 to 36 °C and only vary by small amounts in direct relation to ambient temperature – such a relationship allowed the authors to determine expected brood comb temperatures at each ambient temperature and measure variations from expected results. The brood comb temperature rose 0.56 °C after inoculation with an infectious dose of A. apis (Starks et al. 2000). The authors argue that this small elevation in temperature, representing 20% of the range in normal brood comb temperatures, is sufficient to provide protection against A. apis since only a slight cooling of the bee larvae is needed to cause disease. Of the three treatment‐hives inoculated with A. apis and subjected to the biological fever of the superorganism, only one colony developed minor chalkbrood mummies. Furthermore, the social fever Starks observed in the experimental infection with chalkbrood appears to be preventative as the elevation in brood comb temperature happened before the larvae were killed.