The effects of temperature on the microbiome of the ectoparasite Amblyomma americanum

Ticks are the second leading vector of disease transmission to humans. Though observations of the bacteria carried by ticks started almost a century ago there are still unanswered questions, not least among those being ‘what external factors shape the composition of bacteria within the tick’. The answer to this question is integral to our understanding of the viability and virulence of the diseases ticks carry, and may have implications on how to control them and limit their transmission. There are many instances where distribution of diseases carried by ectoparasites do not mimic the vector’s habitat range, and given that there has been little research looking specifically at external effects on the microbiome of ticks, we proposed to investigate if temperature influenced the microbiome composition of the ectoparasite A. americanum under controlled laboratory conditions. We hypothesized that there would be statistically significant differences among the bacterial community compositions within the microbiomes of A. americanum based on the incubation temperature. In order to test this, colony-reared ticks were exposed to environments with several different incubation temperatures for 15 or 30-days. DNA was then collected and sequenced from these ticks and subsequent metagenomic analysis was conducted to investigate the bacterial composition of their microbiomes. Results indicated that there was no significant difference in microbial communities with respect to temperature, but there was in terms of length of incubation.