Stiretrus

Laporte, 1833

anchor stink bugs

Species Guides

Stiretrus anchorago(anchor stink bug)

Stiretrus is a of predatory stink bugs in the Asopinae, Pentatomidae. occur in the Americas, with records from North America (USA, Canada) and South America (Brazil, Suriname). The genus includes at least eight described species, with S. anchorago (anchor ) being among the better known. Members are of other insects, with documented specialization on cassidine beetles (Chrysomelidae) in some species. Some species exhibit striking color and possible mimicry with their prey.

Stiretrus anchorago by (c) Healthy Yards, some rights reserved (CC BY), uploaded by Healthy Yards. Used under a CC-BY license.

Stiretrus anchorago by (c) skitterbug, some rights reserved (CC BY), uploaded by skitterbug. Used under a CC-BY license.

Pronunciation

How to pronounce Stiretrus: /ˈstaɪ.rɛ.trʊs/

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Identification

Asopinae placement distinguishes Stiretrus from phytophagous pentatomid ; however, -level identification within the genus requires examination of specific morphological characters not detailed in available sources. of S. decemguttatus show up to 17 color pattern variations based on three basic marking sets, which may complicate visual identification.

Images

Habitat

Vacant lots and vegetation patches in urban and semi-urban areas; specifically recorded from areas with Ipomoea asarifolia (Convolvulaceae) on Marajó Island, Brazil. Activity appears concentrated during rainy season in tropical regions.

Distribution

Americas: USA (including Vermont), Canada, Brazil (Pará State—Marajó Island, Maranhão State—São Luis Island), and Suriname.

Seasonality

In tropical regions (Brazil), and nymphs observed mainly during rainy season; temperate (S. fimbriatus) overwinter as adults.

Diet

Predatory; documented prey includes cassidine beetles (Chrysomelidae: Cassidinae), specifically late-instar larvae of Botanochara sedecimpustulata and Zatrephina lineata. Attacks all developmental stages of prey (, larvae, pupae, ), with preference for late-instar larvae. No laboratory preference shown between cassidine when both offered.

Host Associations

Botanochara sedecimpustulata - preyCassidine , late-instar larvae preferred
Zatrephina lineata - preyCassidine , late-instar larvae preferred
Ipomoea asarifolia - associated vegetation plant of prey beetles; site of -prey interactions
Sida sp. - oviposition siteDry calyxes used for clutch deposition and camouflage
Cylindromyia fumipennis - Tachinid fly of S. fimbriatus

Life Cycle

, five nymphal instars, . S. decemguttatus: egg incubation 6 days; nymph stage ~16 days; adult stage ~22 days; total ~44 days. S. fimbriatus: egg development ~9.5 days; nymphal instars average 5.1, 4.3, 4.1, 4.3, and 8.2 days respectively. Nymphal instars separable by width or pronotal width with no overlap.

Behavior

Deposits clutches in dry calyxes of Sida sp. for camouflage. Attacks all prey life stages but preferentially targets late-instar larvae. Exhibits color : S. decemguttatus display up to 17 color patterns from three basic marking sets; nymphs show three color patterns independent of adult patterns. Possible mimicry with chrysomelid beetles associated with Ipomoea asarifolia.

Ecological Role

of cassidine beetles; potentially plays fundamental role in coexistence patterns of prey . increase follows seasonal abundance of prey larvae. May contribute to of cassidine populations.

Human Relevance

Potential agent for cassidine beetles (Chrysomelidae), which include some agricultural pests. No direct economic importance documented.

Similar Taxa

PodisusAlso in Pentatomidae:Asopinae; both are predatory stink bugs with similar and nymphal development patterns. S. fimbriatus and P. placidus have been studied together, sharing similar nymphal instar duration and .
PerillusAnother Asopinae with predatory habits; some show similar color patterns and prey on chrysomelid beetles, potentially causing confusion in field identification.

More Details

Color polymorphism and mimicry

S. decemguttatus exhibits extensive color with up to 17 color patterns. Some patterns resemble cassidine beetles (Botanochara, Zatrephina) that feed on Ipomoea asarifolia, suggesting possible participation in a mimetic ring. This polymorphism may complicate field identification and could represent an anti- or hunting strategy.

Population dynamics

time (T) of 12.65 days and intrinsic growth rate (r) of 0.25 reported for S. decemguttatus under laboratory conditions. increase in the field follows seasonal increase in prey larval abundance.