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The authors have investigated Dermacentor variabilis. They present the description of D. variabilis internal mycoflora carried out via the use of topical application of the fungal inoculum.

Adult mites Balaustium murorum collected from a wild population died in laboratory storage containers and became mouldy. The fungus was identified as Purpureocillium lilacinum (predominate isolate) by 98% internal transcribed spacer (ITS) and beta-tubulin (Bt2a/Bt2b) BLAST match to authentic strains from soil. Larvae, deutonymphs, and adults could be artificially infected by topical application with a 107/ml spore inoculum, resulting in rapid dehydration and an increased mortality. This strain of P. lilacinum was more virulent to larvae than post-larval stages. Post-treatment, P. lilacinum was re-isolated internally with high frequency from cadavers. This P. lilacinum has a 25°C optimal growth temperature, 20-35°C thermal growth range, 0.997 aw optimal water activity (aw), and a minimum 0.96 aw to produce spores. Results indicate that infection with P. lilacinum can occur for population control, most likely during periods of moderate temperature and frequent rainfall. Because P. lilacinum is commercially available as a nematocide, application of P. lilacinum may reduce the effectiveness of Balaustium for plant pest control. This strain P. lilacinum UAMH 11932 is pathogenic to B. murorum and it has been deposited at the University of Alberta Microfungus Collection and Herbarium, Toronto, CAN. [ABSTRACT FROM AUTHOR]

Xeric-suitability and heat tolerance by having a low water loss rate (3%/h) and high upper lethal temperature (48°C) are reported for adults of aBalaustiumsp., which match typical hot, dryBalaustiumhabitat where pollen and arthropod prey on landscape plants are available. They do not have the capacity for water vapour absorption; i.e. the critical equilibrium humidity ≥100% relative humidity with body water losses in unsaturated air. They drink water from droplets, occurring only on occasion and by chance. Prey is their primary source of water. This mite has several features: (1) the inability to recover from heat shock, (2) little heat shock resistance, and (3) no acclimatizing effects by conditioning at a sublethal temperature. In absence of a heat stress-survival mechanism, cooler, shady refuges are sought and used more often that simultaneously help to minimize desiccation risks. This selection for shady spots permits niche differentiation from the bright-redB. murorum, a more desiccation- and heat-resistant species, that coexists in the same habitat and is active in well-lit, sunny locations. [ABSTRACT FROM AUTHOR]