Masked Hunter

Classification

Common name: Masked hunter

Scientific name: Reduvius personatus (Linnaeus, 1758)

Family: Reduviidae (Assassin bugs)

Order: Hemiptera (True bugs)

Description

Adults (Figure 1) are elongate, black or very dark brown color, and somewhat glossy overall and range in size from 17-22 mm (0.686-0.875 inches) in length. The head is relatively small, ovoid with wide-set eyes and a recognizable "neck". The thorax is darker and shinier than the rest of the body. It also has two noticeable protuberances or nubs on the dorsal surface. The wings are held horizontally over the abdomen, have a leathery appearance, and the posterior two-thirds overlap. Upright hairs sparsely cover the body and appendages.

Figure 1. Adult masked hunter. Photograph by allenwoodliffe via iNaturalist, used under a CC BY-NC 4.0 license.

Immature bugs (Figure 2) are typically lighter in color than the adults, although their coloration is not often observed as they usually cover themselves with dust, lint, bits of insect exoskeleton, and various other small items. The materials are glued to the nymph by a sticky, cuticular excretion and can give them the appearance of a living dust ball.

Figure 2. Masked hunter nymph. Note the dust it has covered its exoskeleton with, which gives it a fuzzy appearance. Photograph by carolberney  via iNaturalist, used under a CC BY-NC 4.0 license.

Both the adults and nymphs have short, three-segmented, thickened mouthparts (Figure 3) used to pierce their prey. The mouthparts are curved down and backwards, and when not in use are tucked into a groove between the front pair of legs.

iNaturalist, used under a CC BY-NC 4.0 license.

Range

Masked hunters are native to Europe and western Asia but have been introduced to various places around the world, including Australia, India, South Africa, the Azores, Canary Islands, and North America. In North America, they range throughout the United States and southern Canada. In colder northern areas, they only survive indoors. In southern areas, they can be found indoors and outdoors; outdoors, they prefer dry locations such as under overpasses of divided highways where they feed on bugs that are associated with pigeons and bats. The first specimens were collected in North America in 1905 (Ottawa) and 1917 (Ohio), which suggests they were likely introduced accidentally in the late 1800’s or early 1900’s.

Life History

Masked hunters are nocturnal feeders and spend the daylight hours in protected, dry locations such as under heat registers, under cabinets and cupboards, and inside wall voids and attics. Indoors, they feed on any arthropod they can overpower, including home pests such as silverfish, booklice, house centipedes, millipedes, carpet and hide beetle larvae and adults, bed bugs, and overwintering insects such as multicolored Asian lady beetles, western conifer seed bugs, and cluster flies. They will also feed on any insects that accidentally fly in from outdoors during the warm months (Figure 4).

Figure 4. Masked hunter nymph feeding on a ground beetle that was caught in a spider web. Photograph by gwardenray via iNaturalist, used under a CC BY-NC 4.0 license.

Masked hunters have been reported to have one generation per year in Europe (England, Germany and Ukraine), but two generations per year in Canada. It’s not clear how many generations occur per year further south in North America. Regardless, adults are most common during the summer but have been observed in small numbers during the winter as well. Adults typically survive for 65–90 days but have been recorded to live for as long as 217 days, so individuals observed during the winter may be long-lived specimens.

Medical Importance

Masked hunters do not feed on blood and do not purposefully seek out people or pets to bite or feed on them. However, they will bite in defense when handled or squished (e.g., inside a shoe). The bite is painful, about as painful as a honey bee sting, and takes up to a week to heal. However, there have apparently been no cases of allergic reaction or anaphalyxis associated with a bite reported in the medical literature, so despite the immediate pain there are likely no long-term health issues that arise from masked hunter bites.

Control

Because masked hunters feed on other indoor arthropods, their presence is often an indicator of another underlying pest issue. So the best way to reduce or eliminate the number of masked hunters in a building is to find and eliminate the pests they’re feeding on. Once the prey base is gone, the masked hunters will die out due to lack of food or old age. Broad spectrum insecticides (e.g., pyrethroids) applied to control the underlying pest issue may also help reduce the masked hunter population.

References

iNaturalist. 2023. Masked hunter. Accessed 13 March 2023.

Javahery, M. 2013. Natural history of Reduvius personatus Linnaeus (Hemiptera: Heteroptera: Reduviidae) in North America. Mun. Ent. Zool. 8(2): 685–703.

Scudder, G.G.E. 1992. The distribution and life cycle of Reduvius personatus (L.) (Hemiptera: Reduviidae) in Canada. Journal of the Entomological Society of British Columbia 89: 38–42.

Written by Steve Jacobs, 2006; reviewed 2015. Revised by Michael Skvarla, 2023.