Behavioral fever and therapy in a rickettsia-infected Orthoptera.
Gryllus bimaculatus were infected with an intracellular prokaryote, Rickettsiella grylli, then reared either at fixed temperatures or in a temperature gradient (22-36 degrees C) where they could select the temperature they preferred. Only 50% of the infected insects reared at 28 degrees C or less survived after 20 days, against 75% of those reared at 30 degrees C or more and 90% of those in the temperature gradient. Examination of smears of insect tissue showed that all (100%) of the infected insects reared between 23 and 29 degrees C had developed a strong rickettsial infection. Only 20% of the insects reared in a gradient of temperature showed signs of strong infection. Body temperature of crickets in the temperature gradient, recorded using thin thermocouples, was 33 degrees C in infected crickets and 26.6 degrees C in controls. It is concluded that thermoregulatory behavior was used by the insects to produce a fever when infected with Rickettsiella grylli. This protected them and increased survival capacity.
D000822:Animal Husbandry; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001833:Body Temperature Regulation; D005334:Fever / Q000209:etiology* / Q000503:physiopathology; D006135:Gryllidae / Q000502:physiology*; D009987:Orthoptera / Q000502:physiology*; D012282:Rickettsia Infections / Q000503:physiopathology / Q000628:therapy*; D013696:Temperature