Horismenus

Diverse habitats spanning wild and agricultural systems, including: seed pods of Phaseolus beans (P. vulgaris, P. coccineus, P. lunatus) in Mexican oak woodland, pine-oak woodland, and humid environments from sea level to over 2400 m elevation; seed pods of Pithecellobium dulce in northeastern Brazil; stems of Pereskia aculeata (Cactaceae) and Sechium edule (Cucurbitaceae); citrus groves (Belize); and Atlantic Forest ecosystems (Minas Gerais, Brazil).

Primarily Neotropical, with records from North, Central, and South America. Documented localities include: USA (California, Florida, Georgia, Hawaii, Arizona), Mexico (multiple states across altitudinal gradients), Honduras, Brazil (Amazonas, Minas Gerais, northeastern region), and Ecuador. Some species show narrow altitudinal distributions (e.g., H. missouriensis above 2400 m, H. depressus below 1200 m).

Parasitoids of various insect hosts. Primary parasitoid of bruchid beetles (Acanthoscelides, Zabrotes, Bruchus, Mimosestes, Pseudopachymeria, Stator) within legume seeds; parasitoids of cerambycid larvae (Adetus analis); parasitoid of mantid eggs (Liturgusa maya); hyperparasitoid of braconid wasps (Cotesia invirae) in lepidopteran pupae; and potential hyperparasitoid of congeneric Horismenus species.

• Acanthoscelides obvelatus - hostbruchid beetle host for H. butcheri and H. missouriensis
• Acanthoscelides obtectus - hostbruchid beetle host for H. depressus
• Zabrotes subfasciatus - hostbruchid beetle host for H. depressus
• Adetus analis - hostcerambycid beetle host for two new Brazilian species
• Liturgusa maya - hostmantid host for H. liturgusae
• Cotesia invirae - hostbraconid host for hyperparasitoid H. camobiensis
• Opsiphanes invirae - indirectlepidopteran host of Cotesia invirae, indirect host for H. camobiensis
• Phaseolus vulgaris - host plantcommon bean
• Phaseolus coccineus - host plantscarlet runner bean
• Phaseolus lunatus - host plantlima bean
• Pithecellobium dulce - host plantBrazilian host plant for three new species
• Pereskia aculeata - host plantornamental cactus, invasive in Africa
• Sechium edule - host plantminor crop in Brazil, Argentina, USA

Several species exhibit hyperparasitoid behavior: H. abnormicaulis may act as hyperparasitoid on other Horismenus species; H. camobiensis is a confirmed hyperparasitoid of Cotesia invirae. H. depressus typically dominates parasitoid guilds where present, though shows habitat partitioning (rarely emerges from P. coccineus despite sympatry with P. vulgaris). H. missouriensis shows restricted host plant use, not extending into P. vulgaris populations in sympatry with P. lunatus. Wolbachia endosymbionts detected in H. missouriensis, potentially obscuring mitochondrial population structure.

Biological control agents of agricultural and forest pests, particularly bruchid beetles that damage stored legumes. Natural enemies within multitrophic systems involving wild and domesticated beans, their bruchid herbivores, and higher trophic levels. Hyperparasitoid species contribute to complex food web dynamics in tropical and subtropical ecosystems.

Evaluated as potential biological control agents for Diaprepes abbreviatus and Pachnaeus litus (citrus weevils) in Belize; investigated for control of bruchid pests in bean storage systems; surveyed for biological control of invasive Pereskia aculeata in Africa.

• H. depressus / H. depressoidesH. depressoides described as distinct from H. depressus based on morphological differences, though previously misidentified
• H. missouriensis / H. statorH. stator described as similar to H. missouriensis, requiring careful morphological examination
• H. butcheri / H. dennoi / H. multistriatusH. dennoi and H. multistriatus both similar to H. butcheri, distinguished by subtle morphological characters

• parasitoid
• hyperparasitoid
• bruchid
• Phaseolus
• biological control
• cryptic species
• Wolbachia
• Eulophidae
• Neotropical

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Uncovering Cryptic Parasitoid Diversity in Horismenus (Chalcidoidea, Eulophidae)
• Three new species of Horismenus Walker (Hymenoptera: Eulophidae) associated with seed pods of Pithecellobium dulce (Fabaceae)
• Species of Horismenus Walker (Hymenoptera: Eulophidae) associated with bruchid beetles (Coleoptera: Chrysomelidae: Bruchinae), including five new species
• Microsatellite markers in a complex of Horismenus sp. (Hymenoptera: Eulophidae), parasitoids of bruchid beetles
• Horismenus species (Hymenoptera: Eulophidae) in a bruchid beetle parasitoid guild, including the description of a new species
• New Hosts, Host Plants, and Distribution Records for Horismenus (Hymenoptera: Eulophidae) Species in a Bruchid Beetle Parasitoid Guild Attacking Wild Type Phaseolus Coccineus and P. Vulgaris in Central Mexico
• First Record of the Elusive Ant Parasitoid Horismenus floridensis (Hymenoptera: Eulophidae) in Mexico and New Association with an Ant Host
• Horismenus camobiensis (Hym.: Eulophidae), a new hyperparasitoid of Cotesia invirae (Hym.: Braconidae) in Opsiphanes invirae (Lep.: Nymphalidae) pupae
• Horismenus saturnus n. sp. (Hymenoptera, Eulophidae) a New Parasitoid Wasp from Eggs of Saturniidae (Lepidoptera) from the Atlantic Forest, Minas Gerais, Brazil
• A survey for potential biological control agents of Pereskia aculeata Miller (Cactaceae) in Brazil reveals two new species of Horismenus Walker (Hymenoptera: Eulophidae)
• Inconsistent genetic structure among members of a multitrophic system: did bruchid parasitoids (Horismenusspp.) escape the effects of bean domestication?
• Distributional range expansion and first record of the parasitic wasp Horismenus liturgusae Hansson & Schoeninger, 2014 (Hymenoptera, Eulophidae) on Liturgusa maya Saussure & Zehntner, 1894 (Mantodea, Liturgusidae) from Ecuador
• EXPLORATION IN BELIZE FOR PARASITOIDS ATTACKING EGGS OF CITRUS WEEVILS, AND AN EVALUATION OF PEDIOBIUS IRREGULARIS AND HORISMENUS BENNETTI (HYMENOPTERA: EULOPHIDAE) AS POTENTIAL BIOLOGICAL CONTROL AGENTS OF DIAPREPES ABBREVIATUS AND PACHNAEUS LITUS (COLEOPTERA: CURCULIONIDAE)