Predatory Stink Bug
Meed and David B. Richman
predatory stink bug, Euthyrhynchus floridanus (Linnaeus), is considered a beneficial insect because most
of its prey consists of plant-damaging bugs, beetles, and caterpillars. This stink bug is primarily a
Neotropical species that ranges into southeastern quarter of the United States. It seldom plays more than a
minor role in the natural control of insects in Florida, but its prey includes such economic species as
green stink bug ,
Nezara viridula (Linnaeus); orange
Papilio cresphontes Cramer; velvetbean caterpillar, Anticarsia gemmatalis Hübner; Colorado
potato beetle ,
Leptinotarsa decemlineata (Say); Diaprepes
root weevil ,
Diaprepes abbreviatus (Linnaeus), and others.
females lay egg masses with individual eggs somewhat barrel shaped. Eggs and all five nymphal instars were
illustrated and described in detail by Oetting and Yonke (1975). Eggs of E. floridanus are approximately
1 mm in diameter, with short projects around the operculum, and are laid 20 to 90 at a time.
of the nymphs is less certain, particularly the earlier instars. The available keys are based on the last instar
(5th), but key characters often apply to the 4th instar as well. Hart (1919) included a key to nymphs in the
various stink bug subfamilies. DeCoursey and Allen (1968) published a key to the 5th instar nymphs of 25 genera
of eastern U.S. stink bugs. However, four asopine genera (Alcaeorrhynchus, Andrallus,
Mineus, and Oplomus) reported from Florida were not included. Also listed were field recognition
characters of mature nymphs, with Euthyrhynchus summarized as having head, thorax, lateral and medial
plates unicolorous metallic green, abdomen bright red; length 8 to 9 mm. The mature nymphs reared by Oetting and
Yonke were 10 to 12.5 mm in length. An occasional mistake of a few beginners is to confuse Euthyrhynchus
nymphs with beetles. The latter would have elytra forming a suture dorsally, and the mouthparts would be of the
chewing type. Also, the young stink bugs lack wings and have tube-like piercing-sucking
approximately 1.5 mm; head width, including eyes, 0.7 mm; humeral width 1.0 mm. These are difficult to
distinguish from the 1st instar nymphs of Alcaeorrhynchus grandis (Dallas): both have a blue-black head
and thorax and red abdomen with dark central and lateral "stripes" composed of dorsal and lateral dark colored
plates. Nymphs of this age do not stray far from the egg mass and may be distinguished by association with the
form of the mass and the numbers of eggs; A. grandis masses are in multiple rows and contain 100 to 200
instar: Length 2
to 2.5 mm; head width 0.9 mm; humeral width 1.1 mm. As in other asopine stink bugs, E. floridanus begins
to capture insect prey as a 2nd instar nymph. It looks much like the 1st instar and retains the same coloration.
approximately 4 mm; head width 1.2 mm; humeral width 1.7 mm; colored much as in the 1st instar. The iridescence
of the blue-black markings is more noticeable because of the larger size of the nymph.
instar: Length 6
to 7 mm; head width 1.7 mm; humeral width 2.9 mm; much like the earlier stages in appearance.
instar: Length 8
to 9 mm; head width 2.1 mm; humeral width 4.8 mm. The wing pads, which are blue-black, are prominent, but
otherwise the nymph is much like the preceding stages.
length approximately 12 mm; head width 2.3 mm; humeral width 6.4 mm. Female length 12 to 17 mm; head width 2.4
mm; humeral width 7.2 mm. E. floridanus normally can be distinguished from all other stink bugs in the
southeastern U.S. by a reddish spot at each corner of the scutellum outlined against a blue-black to purplish
brown ground color. Variations occur that might cause confusion with somewhat similar stink bugs in several
genera such as Stiretrus, Oplomus, and Perillus, but these other bugs have obtuse humeri or
at least lack the distinct humeral spine that is present in adults of Euthyrhynchus. In addition, species
of these genera known to occur in Florida have a short spine or tubercle situated on the lower surface of the
front femur behind the apex 1/4 to 1/3 of the femoral length. Hayslip et al. (1953) illustrated species
in Stiretrus, Euthyrhynchus, and Podisus, and a prominently marked E. floridanus was
illustrated by Chittenden (1911).
of E. floridanus are often confused with the banded form of Stiretrus anchorago (Fabricius), from
which it differs in size (S. anchorago is less than 10 mm long), shape (S. anchorago is more
globose and resembles a leaf beetle), and scutellum size (S. anchoragoe has a very large scutellum
covering much of the dorsum of the abdomen).
characters of the predatory subfamily Asopinae serve to eliminate the much more common plant feeding stink bugs:
asopines have the first segment of the beak short and thick, free, only its base being between the bucculae
which converge and unite behind or beneath the beak. The base of beak is close to the end of the tylus. Other
groups of stink bugs have the first segment of beak slender, and embedded between the bucculae which are wide
and parallel. The base of the beak is distinctly separated from the end of the tylus. Blatchley (1926) and
Torre-Bueno (1939) remain the basic keys to stink bugs in the eastern U.S.
floridanus has been
reared in the laboratory by Ables (1975), Oetting and Yonke (1975), and Richman and Whitcomb (1978). At 26 to
27°C and with a photoperiod of 14:10 both Ables and Richman and Whitcomb found that the length of time from egg
to adult was 58 days. The egg stage lasted 18 to 19 days.
(1975) reared South Carolina examples of E. floridanus in the laboratory, providing prey of greater wax
moth larvae, Galleria mellonella (L.), all stages of Mexican
bean beetle ,
Epilachna varivestis Mulsant, and larvae of tobacco
Heliothis virescens (F.). The life cycle was about 89 days under the conditions provided. Oetting and
Yonke (1975) reared Missouri stock of E. floridanus in the laboratory, providing black cutworms,
Agrotis ipsilon (Hufnagel) as a food source. Oetting and Yonke (using a temperature of 24 C and a
photoperiod of 13:11) found the length of time from egg to adult was 100 days, with the egg stage lasting 33
papers (Ables 1975, Oetting and Yonke 1975) included comments on the gregarious nature of the nymphs and even
the adults tended to aggregate at night in the cages. Ables (1975) commented that capture of prey and feeding by
early instars often appeared to be a group effort. He added that such behavior would be of a selective advantage
because it would allow feeding on large prey unavailable to a single nymph.
the Florida State Collection of Arthropods show that E. floridanus has been collected during all months
of the year in Florida. There is a peak in the spring and again in the fall. Of 140 habitat records, 25% have
been ornamentals, 17% citrus; 8% in traps, 6% in weeds and turf, and the remainder in miscellaneous fruits,
trees, and random habitats. Prey records include Nezara viridula (L.), Diaprepes abbreviatus (L.),
a leaf beetle, Bassareus brunnipes (Oliv.), and a flatid planthopper, Ormenaria
(=Monoflata) rufifascia (Walker). Prey reported in the literature includes velvetbean
Anticarsia gemmatalis Huebner, Colorado
potato beetle ,
Leptinotarsa decemlineata (Say), walnut caterpillar, Datana integerrima Grote & Robinson,
alfalfa weevil, Hypera postica (Gyllenhal), a ctenuchid, Lymire edwardsii (Grote), "okra" or
"mallow" caterpillar, Cosmophilla erosa Huebner.
been collected during all months of the year in Florida.
can be collected in a wide variety of habitats because the prey is highly variable.
can be collected by hand or net, and submitted for identification in alcohol-filled vials or dry in pill
special effort to submit egg mass associated with young nymphs.
JR. 1975. Notes on the biology of the predacious pentatomid Euthyrhynchus floridanus (L.). Journal
of the Georgia Entomological Society 10: 353-356.
WS. 1926. Heteroptera or True Bugs of North America with Special Reference to the Faunas of Indiana and
Florida. Nature Publishing Company, Indianapolis. 1116 p.
FH. 1911. Notes on various truck-crop insects. United States Department of Agriculture Bureau of Entomology
Bulletin 82, Part VII, 85-93.
RM, Allen RC. 1968. A generic key to the nymphs of the Pentatomidae of the eastern United States
(Hemiptera: Heteroptera). University of Connecticut Occasional Papers 1: 141-151.
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London xx + 462 p.
CA. 1919. The Pentatomoidea of Illinois with keys to the Nearctic genera. Bulletin of the Illinois Natural
History Survey 13: 157-223.
NC, Genung WG, Kelsheimer EG, Wilson JW. 1953. Insects attacking cabbage and other crucifers in Florida.
Florida Agricultural Experiment Station Bulletin 534: 1-57.
RL. 1971. The insects of Virginia: No. 4. Shield bugs (Hemiptera: Scutelleroidea: Scutelleridae,
Corimelaenidae, Cydnidae, Pentatomidae). Virginia Polytechnic Institute and State University, Research
Division Bulletin. 67: 1-61.
FJD. 1966. The genitalia of North American Pentatomoidea (Hemiptera: Heteroptera). Quaestiones
Entomologicae 2: 7-150.
RD, Yonke TR. 1975. Immature stages and notes on the biology of Euthyrhynchus floridanus (L.)
(Hemiptera: Pentatomidae). Annals of the Entomological Society of America 68: 659-662.
DB, Whitcomb WH. 1978. Comparative life cycles of four species of predatory stink bugs (Hemiptera:
Florida Entomologist . 61:
JR. de la. 1939. A synopsis of the Hemiptera: Heteroptera of America north of Mexico. Part 1. Families
Scutelleridae, Cydnidae, Pentatomidae, Aradidae, Dysodiidae and Temitaphididae. Ent. Americana 19: 141-304.
document is EENY-157 (originally published as DPI Entomology Circulars 174 and 242), one of a series of Featured
Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of
Food and Agricultural Sciences, University of Florida. Published: October 2000. Revised: January 2005. This
document is also available on Featured Creatures Website at http://creatures.ifas.ufl.edu. Please visit
the EDIS Website at http://edis.ifas.ufl.edu. Additional information on these organisms, including many
color photographs, is available at the Entomology and Nematology Department website at
W. Meed, Florida Department of Agriculture and Consumer Services, Division of Plant Industry, and David B.
Richman, University of Florida.
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