A reproducible, host-free feeding system for adult Haemaphysalis longicornis

Haemaphysalis longicornis is a parthenogenetic three-host tick that has expanded from East Asia into Australasia and the Americas, where it poses increasing veterinary and public-health concern. Yet, laboratory research has been constrained partly by the absence of a reliable artificial feeding system. Here, we establish and optimise an artificial, host-free in vitro feeding platform for adult H. longicornis, utilising a thin silicone membrane that overcomes the species' short hypostome and limited mouthpart mobility. Across six independent experiments using field-collected parthenogenetic adult females from Australia, 67 % (35/52) of ticks attached and 74.3 % (26/35) engorged, achieving a mean engorgement weight of 161 mg (range: 44.8-275 mg), a mean egg mass of 67 mg (11.4-137 mg) and mean bloodmeal-to-egg conversion efficiency of 40 % (range: 16.7-59.9 %). All engorged females oviposited and produced viable larvae, with egg hatchability exceeding 92 % (mean ∼98 %) and engorgement weight strongly associating with fecundity (r = 0.82). Feeding was completed within 2-7 days, comparable to, or shorter than, feeding on live hosts; hair extract treatment did not enhance feeding or reproductive performance. This host-free system essentially replicates natural feeding performance under controlled laboratory conditions and supports the complete reproductive cycle of adult H. longicornis without an animal host. It provides a reproducible and ethical platform for acaricide and vaccine discovery and studies of tick physiology and pathogen-vector interactions, establishing a foundation for standardised, scalable and welfare-compliant tick research within a One Health framework.