Haller’s organ functionality is critical for ticks to prevent dehydration and starvation

Sunday, November 13, 2022

9:12 AM – 9:24 AM PT

Location: Vancouver Convention Centre, Meeting Room 111/112

Presenting Author(s)

JB

Joshua B. Benoit

Professor
University of Cincinnati
Cincinnati, Ohio

Co-Author(s)

JK

Jasmine Kennedy

University of Cincinnati
Cincinnati, Ohio
MU

Melissa R. Uhran

University of Cincinnati
Cincinnati, Ohio
MK

Melissa Kelley

University of Cincinnati
Cincinnati, Ohio
ES

Evan S. Smith

University of Cincinnati
Cincinnati, Ohio
TA

Thomas Arya

University of Cincinnati
Cincinnati, Ohio
KO

Kennan J. Oyen

Postdoctoral Researcher
University of Cincinnati
Cincinnati, Ohio
AB

Ayesha Benton-Anderson

University of Cincinnati
Cincinnati, Ohio
SC

Shyh-Chi Chen

Postdoc Fellow
University of Cincinnati
Cincinnati, Ohio
Pia Olafson

USDA-ARS
Kerrville, Texas

Off-host periods between bouts of blood-feeding are critical for ticks as this represents a period when environmental stress, particularly dehydration, can impact tick survival. To prevent dehydration, ticks must be able to move into high humidities for water vapor uptake. This allows ticks to remain hydrated and conserve energy. If their humidity sensing is impaired, it would prevent the ticks from being able to move to high humidities, prompting more frequent dehydration/rehydration and nutrient reserve breakdown. Here, we examined the ability of ticks to sense humidity by manipulating the Haller’s organ (located on their first set of legs) and how altered humidity detection impacts tick survival. The adult Dermacentor variabilis (American dog tick) and adult female Amblyomma americanum (lone star tick) were used to observe humidity preference, survival, and field studies after the manipulation of Haller’s organs. Either permanent (cutting or heat ablation) or temporary blocking (silicone covering) impairs the ability of ticks to rest in areas with high humidity that are necessary to maintain hydration. Impaired detection of humidity did not impact tick survival when individuals were held under stable, humid conditions, but conditions with variable conditions (wet and dry areas) resulted in reduced tick survival. This increased mortality is likely a combination of increased dehydration stress and more rapid utilization of energy reserves required for water vapor uptake. These studies confirm that the Haller’s organ is essential for humidity sensing in ticks and a lack of humidity detection reduced tick survival.