University of Kentucky Entomology/Kentucky Critter Files/Kentucky Insects/True Bugs/Assassin Bugs & Ambush Bugs
    University of Kentucky Department of Entomology - Kentucky Critter Files
Critter Files HOME»

ARTHROPODS:

Insects»

Spiders»

Centipedes»

Millipedes»

Sowbugs»

Harvestmen»

Mites & Ticks»

Scorpions»

GUEST CRITTERS:
Slugs»
SEARCH:
THUMBNAILS:
A-E»|F-M»|N-Z»

Identification Tips»

About the Critter Files»

Links»

Assassin Bug ASSASSIN BUGS & AMBUSH BUGS
Critter Files/Insects/True Bugs/Assassin & Ambush Bugs
By Blake Newton
University of Kentucky Department of Entomology
   
Common Kentucky Assassin Bugs & Ambush Bugs:
 
TAXONOMY

KINGDOM: Animalia | PHYLUM: Arthropoda | CLASS: Insecta | ORDER: Hemiptera | FAMILY: Reduviidae (assassin bugs & ambush bugs)

 
Other Names: Reduviids
 
WHAT IS AN ASSASSIN BUG?
LIFE CYCLE
ECOLOGY
PEST STATUS
COMMON KENTUCKY ASSASSIN & AMBUSH BUGS
COLLECTING & PHOTOGRAPHY
ASSASSIN BUG FACTS
MYTHS, LEGENDS, AND FOLKLORE
 
WHAT IS AN ASSASSIN BUG?

Assassin Bugs and Ambush Bugs are in the order Hemiptera which also includes stinks bugs, leaf-footed bugs, and other insects.  All insects in Hemiptera share a few characteristics, including piercing and sucking mouthparts, and wings which are membranous and clear at the tips, but hardened at the base.

Assassin bugs and ambush bugs are in the family Reduviidae.  Insects in this family are distinguished from other members of Hemiptera by their short, 3-segmented beaks (most Hemiptera have 4-segmented beaks).

WHAT IS AN AMBUSH BUG?
Technically, ambush bugs are a type of assassin bug, but there are a few differences.  Assassin bugs are usually dark-colored, with combinations of gray, green, and black.  Assassin bugs also have long, narrow heads compared to ambush bugs.  Ambush bugs are usually stoutly built and typically have bright colors: yellow, red, or orange.  Ambush bugs have thickened front legs which are used to capture prey.  Assassin bugs will also use their front legs to capture prey, but their front legs are not as thickened as those of ambush bugs.

 
COMPARISON: Assassin Bug vs. Ambush Bug
Assassin Bug
Assassin Bug (R. Bessin 2000)
Ambush Bug
Ambush Bug (B. Newton, 2004)
SIZE: Assassin bugs up to 1 1/2", ambush bugs up to 1/2"
 
LIFE CYCLE

Like all members of the order Hemiptera, assassin bugs and ambush bugs go through a simple metamorphosis with egg, nymph, and adult stages.  In warm months, females lay eggs which are stuck in clusters to leaves and stems.  After hatching, the wingless nymphs grow and molt 4 times (some species molt 7 times) before becoming full-sized, winged adults.  Adults are usually the overwintering stage.

 
Wheel Bug Nymph
Wheel Bug Nymph (R. Bessin, 2000)
Assassin bug nymph, Zelus sp.
Assassin bug nymph, Zelus sp.
(B. Newton, 2004)
 
ECOLOGY
Most members of the family Reduviidae are predators.  The nymphs and adults capture insects and other arthropods in their raptoral (prey-grabbing) front legs, then use their sharp beaks to suck fluids from their victim.  They also inject a small amount of poison that paralyzes their prey, making it easier to handle.  Assassin bugs actively hunt for prey, but ambush bugs wait motionless for prey to come to them.
Wheel Bug feeding on a caterpillar
Wheel Bug feeding on a caterpillar
(Image courtesy USDA Photo Set)
 

In general, assassin bugs hunt on various types of vegetation, including trees, weeds, and bushes.  Ambush bugs usually hunt on flowers.  Assassin and ambush bugs are able to fly, but they are poor fliers.

Although assassin bugs and ambush bugs are fierce predators, they are sometimes eaten by birds, rodents, and large predatory arthropods, such as spiders, praying mantids, and even other assassin and ambush bugs.  Assassin bug and ambush bugs are especially vulnerable to predation when they are in the nymph stage.

PARASITIC REDUVIIDS: A few species in this family are parasites that feed on the blood of mammals.  The Bloodsucking Conenose, Triatoma sanguisuga, is a common example.  It normally feeds on rodents, but will sometimes bite humans that sleep near rodent nests.

 
PEST STATUS

Bugs in the family Reduviidae are considered pests when they bite humans.  Common predatory assassin bugs, like the Wheel Bug, will occasionally inflict painful bites.  For the most part, however, assassin and ambush bugs have reputations as beneficial insects because they feed on other arthropods.

Only the parasitic reduviids, such as the conenose bugs, are true pests.  Their bites sometimes cause severe allergic reactions.  However, they are not frequently encountered in Kentucky.  Read more about conenose bugs and other biting bugs at this Texas A&M Extension website:
http://citybugs.tamu.edu/FastSheets/Ent-1018.html

 
 
COMMON KENTUCKY ASSASSIN & AMBUSH BUGS

WHEEL BUG
GENUS and SPECIES: Arilus cristatus
The most commonly seen assassin bug in Kentucky is probably the Wheel Bug, Arilus cristatus, pictured below.  At 1 1/2", this silver-gray insect is the largest assassin bug that lives in Kentucky.  It gets its name from the structure on its thorax which resembles a gear or saw blade.  The wheel bug is notorious for its painful bite, but it only bites on accident or if handled carelessly.  The nymph of the wheel bug is pictured above.

 
Wheel Bug
Wheel Bug (R. Bessin, 2000)

SPINED ASSASSIN BUG
GENUS and SPECIES: Sinea diadema
Sinea diadema, pictured below, is usually called the Spined Assassin Bug.  It is often found on goldenrod and other wildflowers.  Because it is smaller than the wheel bug (at about 3/4") it is not noticed as often, but the spined assassin bug is just as common, if not more so.

 
Spined Assassin Bug
Spined Assassin Bug (R. Bessin, 2000)
BEE ASSASSIN
GENUS: Apiomerus crassipes
As its name suggests, the Bee Assassin, Apiomerus crassipes, is well-known for feeding on bees.  Bee assassins are good fliers, and will patrol flowering plants that are visited by bees, flies, and other pollinating insects.  Bee assassins are usually dark in color with yellow or red markings on the sides of the abdomen, and are about 3/4" long.  The one below was photographed in Rowan County.
 
Bee Assassin, Apiomerus crassipes
Bee Assassin, Apiomerus crassipes (B. Newton, 2004)
ZELUS spp.
GENUS: Zelus
Pictured below is an assassin bug in the Zelus genus, probably Z. exsanguis or Z. luridus.  These assassin bugs are commonly found in trees and shrubs.  They are about 3/4" long and have bright green bodies with dark highlights.  A Zelus nymph is pictured above.
 
Zelus exsanguis
Zelus sp. (B. Newton, 2002)
PSELLIOPUS spp.
GENUS: Pselliopus
Common assassin bugs in the Pselliopus genus are distinguished by their black-banded, bright orange bodies.  Adults are apx 1" long.
 
Pselliopus sp. nymph
Pselliopus sp. nymph (B. Newton, 2004)
Pselliopus sp. adult
Pselliopus sp. adult (B. Newton, 2005)

CORSAIR
GENUS: Melanolestes
Corsairs are unusual assassin bugs in the Melanolestes genus.  Male corsairs have full-sized wings and are sometimes found hunting on leaves and flowers.  Female corsairs, like the one pictured below, have stunted, non-functional wings.  They hunt under rocks, logs, and fallen leaves for ground-dwelling prey like caterpillars, crickets, and earthworms.  Corsairs are about 1" long.  Visit this page at BugGuide.net for a picture of winged male corsair:
http://bugguide.net/node/view/7334/bgimage

 
Female corsair, Melanolestes sp.
Female corsair, Melanolestes sp. (B. Newton, 2004)
AMBUSH BUGS
GENUS: Phymata
Ambush Bugs, like the one below, look different from other bugs in the Reduviidae family.  In fact, some scientists place ambush bugs in their own family, Phymatidae.  Ambush bugs are short and stout compared to assassin bugs, and their front legs are thicker and shaped like praying-mantis legs.  Ambush bugs are commonly found on a variety of wildflowers where they wait in ambush for bees, flies, and other prey.  
 
Ambush Bug in the Phymata genus
Ambush Bug in the Phymata genus (R, Bessin, 2000)
Ambush Bug nymph
Ambush Bug nymph (B. Newton, 2005)
 
COLLECTING & PHOTOGRAPHY

Assassin bugs and ambush bugs are always an interesting addition to an insect collection.  Look for assassin bugs in any weedy or bushy area during warm months, especially in hedge rows, along roadsides and fence rows, in gardens, or along trails.  Ambush bugs are commonly found on wildflowers during the summer, but they are especially common on goldenrod in late summer and early fall.  Most assassin bugs and ambush bugs are slow moving: if you find them, they are usually easy to catch.  They will also usually stay still for a photograph.  If you are patient, you may be able to snap a picture of one as it slowly consumes its prey.  Although assassin bugs and ambush bugs are not considered dangerous, most can bite, and should not be handled.

Assassin bugs can also make great pets, and usually do well in captivity, although most species only live for a year or two (and they can't be handled!).  For more information about keeping pet assassin bugs, visit our Pet Bugs page: Assassin Bugs.

 
ASSASSIN BUG FACTS

Because assassin bugs are such good predators, scientists are interested in using them as natural control agents of crop pests.  Read about an important assassin bug predator from California:
http://www.ipm.ucdavis.edu/PMG/NE/assassin_bugs.html

 
MYTHS - LEGENDS - FOLKLORE

Do you know any myths, legends, or folklore about assassin bugs or ambush bugs?  Let us know if you do!


Original document: 25 May 2004
Last updated: 19Oct 2006

Photos courtesy R. Bessin and B. Newton, University of Kentucky, except Wheel Bug Feeding on Caterpillar, USDA Photo Set; used with permission.
The Kentucky Critter Files are maintained by Blake Newton, Department of Entomology, University of Kentucky.
Contact: blaken@uky.edu

 

University of Kentucky Entomology/Kentucky Critter Files/Kentucky Insects/True Bugs/Assassin Bugs & Ambush Bugs