Sleep: An Essential and Understudied Process in the Biology of Blood-Feeding Arthropods

Abstract

Understanding the biology of blood-feeding arthropods is critical to managing them as vectors of etiological agents. Circadian rhythms act in the regulation of behavioral and physiological aspects such as blood feeding, immunity, and reproduction. However, the impact of sleep on these processes has been largely ignored in blood-feeding arthropods, but recent studies in mosquitoes show that sleep-like states directly impact host landing and blood feeding. Our focus in this review is to discuss the relationship between sleep and circadian rhythms in blood-feeding arthropods along with how unique aspects such as blood gluttony and dormancy can impact sleep-like states. We highlight that sleep-like states are likely to have profound impacts on vector-host interactions but will vary between lineages even though few direct studies have been conducted. A myriad of factors, such as artificial light, could directly impact the time and levels of sleep in blood-feeding arthropods and their roles as vectors. Lastly, we discuss underlying factors that make sleep studies in blood-feeding arthropods difficult and how these can be bypassed. As sleep is a critical factor in the fitness of animal systems, a lack of focus on sleep in blood-feeding arthropods represents a significant oversight in understanding their behavior and its role in pathogen transmission.

Circadian regulation of locomotion, respiration, and arousability in adult blacklegged ticks (Ixodes scapularis)

“…Sleep and sleep dynamics are critical for vector competence, and detailed information about tick sleep is lacking 46 . We provided sleeping ticks with a variety of stimuli to test their daytime state.…”

Aedes albopictuscolonies from different geographic origins differ in their sleep and activity levels but not in the time of peak activity

“…aegypti (Ajayi et al 2022). Sleep-like states in Aedes, Culex, and Anopheles mosquitoes are characterized by stereotypical postural changes, increased arousal thresholds, prolonged immobility during specific periods of the day, and sleep rebound after prior deprivation (Ajayi et al 2020(Ajayi et al , 2022(Ajayi et al , 2023. In the fruit fly, Drosophila melanogaster, even though sleep is a highly conserved physiological function, extensive variations in sleep duration or pattern have been observed both among species and between individuals of the same species (Harbison et al 2013).…”