Tick Bites Tick Tiny Male Puts the Bite on an Engorged Female

September 21, 2018

Researchers conducting a tick survey in Alaska unexpectedly found themselves seeing an unusual photo of a tick.

A tiny adult female tick taken from a red squirrel was carrying its own parasitic hitchhiker, the adult male tick of the same species, Ixodes angustus, and it appeared to be grabbing the female tick not in passion, but in hunger.

When the scientists examined the blood-filled female tick with a scanning electron microscope (SEM), they found the much smaller male tick clinging to the underside of the female tick’s body, digging deeply into the food with its piercing mouthparts.

The blood-eating ticks belong to the genus Ticks, which are hard-bodied ticks (the other major family of ticks, the Argasidae, are soft-bodied ticks). According to the Department of Entomology and Nematology at the University of California, Davis, hard ticks have three life stages – larvae, nymphs, and adults – and the insects typically take a blood meal from a host at each stage.

In a new study, researchers from Georgia Southern University, the Alaska Department of Environmental Conservation and the Alaska Department of Fish and Game write that the tick species I. angustus has been linked to the spread of Lyme disease and is the most abundant species on rodents and other mammals in British Columbia and Alberta, Canada, and Alaska, describing evidence of tick-to-tick feeding.

By feeding on another tick, the male insects described by the study authors are practicing a behavior known as hyperparasitism – when parasites skip the host animal entirely and feed directly on their bleeding companions, eliminating the middle man.

A second male tick also attached itself to the female and mated with her, but it fell off as the researchers prepared to scan the specimen, they wrote in the study.

The remaining male tick’s mouthpiece penetrated the female’s body area near her head and genital opening, while his palms – a pair of elongated appendages near his mouth – were spread out over her exoskeleton, positioning him in a characteristic feeding position, the scientists noted.

And the male in the image is likely not the only hitchhiker who has fixed himself on the female for a free lunch. Another scar on her body – a small puncture visible just below and to the left of her central genital opening – suggests that another hungry tick is also feeding on the female, the researchers report.

Hyperparasitism is common in soft ticks, but is thought to be less common in their hard-bodied cousins and has not previously been found in the hard tick species I. angustus. However, previous studies have documented not only that male ticks of the genus Ixodes parasitize female ticks, but also evidence of feeding scars on female ticks like those found in the new study. The authors conclude that this evidence, along with the new findings, suggests that male sclerotia ticks may use female ticks as meal tickets more frequently than once thought.