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Alydidae
Alydidae
Alydidae
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Alydidae
Alydus calcaratus
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Heteroptera
Superfamily: Coreoidea
Family: Alydidae
Amyot & Serville, 1843
Subfamilies

Alydinae
Micrelytrinae
and see text

Synonyms

Coriscidae Stichel, 1925

Alydidae, commonly known as broad-headed bugs, is a family of true bugs very similar to the closely related Coreidae (leaf-footed bugs and relatives). There are at least 60 genera and 300 species altogether. Distributed in the temperate and warmer regions of the Earth, most are tropical and subtropical animals; for example Europe has a mere 10 species, and only 2 of these occur outside the Mediterranean region.[1]

Names

[edit]

Broad-headed bugs are known as knobe in the Meto and Funai Helong languages of West Timor, Indonesia.[2]

Description

[edit]

Broad-headed bugs are up to 10–12 millimetres (0.4–0.5 in) long, and have slender bodies. Some have long and very thin legs. The most notable characteristics of the family are that the head is broad, often similar in length and width to the pronotum and the scutellum, and that the last antennal segments are elongated and curved. The compound eyes are globular and protruding, and they also have ocelli. The femora of the hindlegs bear several strong spines; the tarsus has three segments. Most species have well-developed hemelytra (forewings), allowing them to fly well, but in some the hemelytra are vestigial. The membranous part of the hemelytra have several closely spaced long veins.

Alydidae are generally of dusky or blackish coloration. The upperside of the abdomen is usually bright orange-red. this color patch is normally not visible as it is covered by the wings; it can be exposed, perhaps to warn would-be predators of these animals' noxiousness: They frequently have scent glands that produce a stink considered to be worse than that of true stink bugs (Pentatomidae). The stink is said to smell similar to a bad case of halitosis.

Sometimes the adults have reduced wings. Both, nymphs and adults of some species, such as Dulichius inflatus and Hyalymenus spp. are ant mimics and live in ant nests.[3]

Ecology

[edit]

These bugs mainly inhabit fairly arid and sandy habitat, like seashores, heathland, steppe and savannas. Their main food is seeds, which they pierce with their proboscis to drink the nutritious fluids contained within. Some are economically significant pests, for example Leptocorisa oratoria on rice.

Systematics

[edit]

Two major lineages are generally accepted as subfamilies; a third (the Leptocorisinae[4]) is now placed as a tribe Leptocorisini of the Micrelytrinae.[5]

Genera

[edit]

These 60 genera belong to the family Alydidae:[1][6]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Alydidae

View on Grokipedia
from Grokipedia
Alydidae, commonly known as broad-headed bugs, is a of true bugs belonging to the order , suborder , and superfamily Coreoidea. This encompasses approximately 250 distributed across about 53 genera worldwide, divided into two main subfamilies: Alydinae (further split into tribes Alydini and Daclerini) and Micrelytrinae (split into tribes Micrelytrini and Leptocorisini). Members are typically slender measuring 8–20 mm in length, featuring a distinctive broad, triangular head that is nearly as wide as the pronotum, along with elongate bodies that often appear wasp-like in adults and ant-mimicking in nymphs. These bugs are predominantly phytophagous, with Alydinae species feeding primarily on plants in the family (), often targeting seeds, while Micrelytrinae tend to feed on grasses or have less specialized host plants. Nymphs exhibit myrmecomorphy, resembling in form and behavior for protection, and both nymphs and adults may aggregate using pheromones produced by females. The life cycle typically involves overwintering as eggs laid singly on the ground near host plants, with five nymphal instars hatching in spring, followed by adult emergence in late spring or early summer; multiple generations (2–3) can occur annually in warmer climates. Alydidae are found worldwide but achieve greatest diversity in tropical and subtropical regions, including the Neotropics (from about 24°N to 30°S ), with notable Holarctic genera such as Alydus and Megalotomus. They inhabit vegetation along roadsides, in wooded areas, and near crop fields, often in association with nitrogen-rich substrates like decaying matter. Economically, most species are of minor significance, though some, like Neomegalotomus parvus in the Neotropics, can damage crops such as soybeans by feeding on seeds, causing yield reductions, dark marks, and inhibited germination, or even transmitting diseases like yeast spot.

Nomenclature and Description

Common and Scientific Names

The family Alydidae is commonly known as the broad-headed bugs, a name primarily referring to the distinctive head shape in the Alydinae. In certain regions, such as in , these insects are referred to as "knobe" in the Meto and Helong languages, where the term denotes the rice ear bug. The scientific name Alydidae was formally established by the French entomologists Charles Jean Baptiste Amyot and Jean Guillaume Audinet-Serville in their 1843 work Histoire naturelle des insectes Hémiptères, with the Alydus (originally described by in 1803). The etymology of Alydidae derives from this , Alydus; its origin is unclear. Historically, the of Alydidae has seen revisions; initially recognized as a distinct family in 1843, it was later classified by some authors as a (Alydinae) within or even as a , before being reinstated as a separate family in modern . Synonyms for the family include Coriscidae, proposed by Hermann Stichel in 1925, reflecting earlier taxonomic groupings of related coreoid bugs.

Morphological Characteristics

Alydids exhibit a slender, elongate body form, typically measuring 7–20 mm in length. The overall coloration is dusky or blackish, though the upperside of the features a bright orange-red patch that is usually concealed beneath the wings. The head is notably broad and triangular, often nearly as wide as the , giving the family its of broad-headed bugs. It bears globular, protruding compound eyes and three ocelli positioned behind them. The antennae are four-segmented and elongated, with the fourth segment distinctly curved. The thorax includes a trapezoidal pronotum that is less than twice the width of the head (including eyes), and a broad scutellum. The legs are generally slender, with the hind femora armed with several strong spines and the tarsi three-segmented. The wings consist of well-developed hemelytra in most , enabling flight, though some taxa in the subfamily Micrelytrinae possess vestigial wings; the forewing membrane displays numerous longitudinal veins. The abdomen is elongate and typically hidden under the folded wings, with metathoracic that produce a noxious when disturbed. A piercing (rostrum) is present for feeding. is minimal.

Distribution and Habitat

Global Distribution

Alydidae, commonly known as broad-headed bugs, are predominantly distributed in tropical and subtropical regions across all major zoogeographic zones, with limited extensions into temperate areas and complete absence from polar regions. The family encompasses approximately 250 in about 53 genera globally, reflecting a cosmopolitan but uneven presence shaped by climatic preferences. Highest diversity occurs in warmer climates, where the majority of thrive, underscoring their adaptation to non-arid, vegetated environments. In the Neotropics, spanning Central and from approximately 24°N to 30°S, Alydidae exhibit high diversity with 21 genera and numerous species, including notable representatives in legume-associated habitats. In , Alydidae are widespread, with notable concentrations in ; for instance, species in the genus are prevalent from the through to , often linked to agricultural landscapes. Africa supports a substantial portion of the family's range, spanning West and Central regions where genera like Riptortus occur on crops. features several representatives, including endemic taxa such as Daclera rufescens, restricted to tropical coastal . North America hosts about 30 species across 13 genera, ranging from to via Holarctic lineages like Alydus and Megalotomus. A 2016 checklist confirmed 8 in 6 genera within , all representing new state records and highlighting underdocumented regional diversity. In , the family is sparsely represented with roughly 10 , primarily confined to Mediterranean areas, and only 2 extending northward into cooler temperate zones; the Palearctic region overall includes 8 genera. Endemism is evident in certain genera and tied to specific landmasses, such as Australian endemics, while broader patterns suggest an ancient tropical origin with subsequent dispersals facilitated by historical climatic shifts. Recent distributional checklists, including those from onward, continue to refine these estimates, revealing ongoing discoveries in understudied areas.

Habitat Preferences

Alydidae species inhabit a variety of open and disturbed environments, including semiarid and sandy areas such as seashores, heathlands, steppes, and savannas, as well as roadsides, agricultural fields, and edges of wooded areas, often in association with their host plants in well-drained soils. These bugs show a preference for open or disturbed habitats, though some occur in more vegetated settings. Their slender, elongate bodies are adapted for navigating through low vegetation, enabling efficient movement in these settings while minimizing exposure to predators. Within these environments, Alydidae are commonly associated with monocotyledonous plants such as grasses and weeds, particularly members of the subfamily Micrelytrinae, which feed primarily on graminaceous hosts. Pest species like those in the genus Leptocorisa are frequently found in agricultural fields, including rice paddies, where they exploit monocot crops and associated weeds. Microhabitats typically include ground-level zones or low vegetation layers, with some nymphs, such as those of Alydus calcaratus, developing in ant nests, leveraging myrmecomorphic traits for protection. These demonstrate tolerance to dry conditions, a key reflected in their distribution across various zones and their ability to persist in habitats with limited moisture. However, agricultural intensification poses potential threats by altering preferred open habitats, though comprehensive data on climate-induced shifts remain limited as of recent assessments.

Ecology and Behavior

Diet and Feeding

Members of the Alydidae family are predominantly phytophagous , with feeding habits varying by subfamily; Alydinae species primarily target seeds of in the family, while Micrelytrinae often feed on seeds of grasses () and weeds, using their piercing-sucking mouthparts to extract nutrient-rich contents. Some Alydinae may occasionally scavenge high-nitrogen substrates like carrion, vertebrate fecal matter, or ammonia-rich materials, though feeding predominates; no predatory behavior is observed across the family. In Micrelytrinae, host plants include monocotyledons such as (Oryza sativa), where feeding causes significant damage known as "pecky rice," characterized by chalky spots and reduced grain quality. Alternative hosts include grassy weeds like Echinochloa crus-galli, Digitaria ciliaris, and , which serve as important resources for population buildup outside of crop seasons. Species such as , L. acuta, and L. chinensis are major pests of in , with spatial distribution patterns influenced by climatic factors that align with rice-growing regions, leading to yield losses of up to 50% in affected fields. The feeding mechanism involves inserting a stylet into the to inject salivary enzymes that liquefy the , allowing the bugs to suck up the predigested fluids without consuming tissues like or . This process targets developing grains during the soft , enhancing nutrient extraction efficiency while avoiding broader damage.

Life Cycle and Reproduction

Alydidae, like other members of the , exhibit hemimetabolous development, characterized by incomplete consisting of three primary life stages: , , and . Oviposition varies by and region, with eggs laid singly on the ground near host plants in many temperate Alydinae or in small clusters or rows of 10–20 on host plant foliage (e.g., grasses or ) in some Micrelytrinae; the stage typically lasts 6–9 days (averaging 7.5 days) under temperatures ranging from 20.5–34.3°C. These eggs are oval, shiny, and reddish-brown, with females capable of producing 100–300 eggs in total, though some like Stenocoris elegans average 135.1 eggs over 33.5 days of oviposition. In temperate regions, eggs may enter to overwinter, hatching in early spring. Nymphs emerge and undergo five instars, resembling smaller, wingless versions of adults with pale yellow-green coloration; wing pads appear from the third instar onward. Nymphal development generally spans 19–22 days but can extend to 4–6 weeks depending on and food availability, during which they feed primarily on shortly after hatching—often within 3–4 hours. Each in species like Alydus eurinus lasts approximately 2.78 days on average, progressing through ant-like morphologies in early stages to more bug-like forms later. The overall egg-to-adult cycle in tropical environments takes 35–70 days, influenced by environmental factors such as during drier periods, when individuals migrate to shaded areas. Adults emerge fully winged and sexually mature, with lifespans ranging from 62–89 days under optimal conditions of 27–28°C and 80–82% relative humidity, though some species like Alydus eurinus can live up to 180 days for females (average 66.8 days) and 176 days for males (average 76.1 days). is sexual, with occurring on shortly after adult emergence for males and after about 9 days for females; oviposition begins 3–4 days post-mating, following a preoviposition period averaging 21 days (range 18–24). Females deposit eggs near suitable food sources to ensure nymphal survival. In cooler climates, populations are often univoltine with one generation per year due to , while tropical regions support multivoltine cycles with multiple generations. Population dynamics of Alydidae are closely tied to warm seasons and host availability, with peaks typically occurring from to November in regions like the , driven by abundant or grains. Nymphal and adult densities fluctuate with seed maturation cycles, and short-day conditions can induce reproductive in adults, limiting generations in temperate zones. Overall, these patterns ensure with ephemeral resources like ripening seeds, which nymphs exploit for development.

Defensive Mechanisms and Interactions

Alydidae employ a combination of morphological and behavioral adaptations for defense, with myrmecomorphy serving as a primary strategy in many species. Nymphs and adults of several alydid species mimic through resemblances in body shape, coloration, and movement, deterring predators that avoid stinging or aggressive via . For instance, nymphs of Hyalymenus tarsatus exhibit ontogenetic changes in color and size across instars, allowing them to progressively resemble differently sized and colored such as those in the Ectatomma, enhancing their protective during development. Studies on European alydids, such as Alydus calcaratus mimicking Formica pratensis , indicate that mimicry accuracy is highest in color and behavior but lower in size and overall shape, with mimics often matching ant appendage proportions to replicate gait effectively. In addition to , chemical defenses provide a secondary line of protection against predators. Adults of Alydidae possess metathoracic that release noxious volatile compounds, such as butyric and hexanoic acids in Alydus eurinus, when threatened, producing an odor that repels attackers. These secretions are particularly effective against avian predators, though less so against spiders in some , highlighting stage-specific variations in defense efficacy. Nymphs also utilize similar glandular mechanisms, contributing to rapid by reducing predation pressure. Both nymphs and adults may aggregate using pheromones produced by females, further aiding protection. Ecological interactions further shape alydid survival strategies, including occasional where some inhabit ant nests for protection without true integration or eusocial behavior. Alydids face predation from birds, spiders, and other , as documented in A. eurinus, alongside by egg parasitoids such as Ooencyrtus nezarae and Gryon japonicum in like Riptortus pedestris. In agricultural contexts, alydids are targeted by insecticides like for in and fields, which inadvertently reduce populations of their natural enemies and disrupt biocontrol potential. Recent research on alydid remains limited post-2020, with most studies focusing on pest like R. pedestris rather than broader defensive interactions.

Systematics and Diversity

Classification and Phylogeny

Alydidae belongs to the order , suborder , and superfamily Coreoidea, where it is closely related to , though phylogenomic analyses indicate both families are non-monophyletic. The family was formally established by Amyot and Serville in 1843 under the name Alydides, initially encompassing a broader assemblage of coreoid taxa that included elements later segregated into separate subfamilies or even families due to evolving morphological and molecular criteria. Early classifications often merged Alydidae with at the subfamily or tribal level, reflecting shared traits like slender bodies and plant-feeding habits, but subsequent revisions affirmed its distinct familial status. Phylogenetic studies have identified two major lineages within Alydidae: the Alydinae (including tribes Alydini and Dacleri) and the Micrelytrinae (including tribes Micrelytrini and Leptocorisini). A phylogenomic investigation by Forthman et al. (2019) utilized hundreds of ultraconserved element loci across Coreoidea taxa, recovering a monophyletic Coreoidea with Rhopalidae as sister to Alydidae + . The analysis found both Alydidae and non-monophyletic, with the Coreidae subfamily Pseudophloeinae sister to Alydinae, supported by synapomorphies such as a simple ostiolar peritreme. Subsequent studies, including Forthman et al. (2022), have confirmed these findings, suggesting ongoing taxonomic revisions for Coreoidea, though traditional classifications within Alydidae persist. The evolutionary history of Alydidae traces back to an ancient lineage within Coreoidea, with the superfamily's origins likely in the era, as evidenced by fossil representatives from the and periods. However, no fossils definitively attributable to Alydidae have been described, representing a notable gap in the paleontological record that hinders precise dating of family-level divergences. Recent taxonomic revisions, including the reclassification of the former subfamily Leptocorisinae as the tribe Leptocorisini within Micrelytrinae, stem from integrated morphological and molecular evidence, with ongoing phylogenomic efforts continuing to refine internal relationships and broader Coreoidea .

Subfamilies and Genera

The family Alydidae is classified into two subfamilies: the predominant Alydinae and the less diverse Micrelytrinae, the latter comprising the tribes Micrelytrini and Leptocorisini. Alydidae encompass approximately 300 species across about 60 genera worldwide, as of 2025, with the majority concentrated in tropical and subtropical regions. Diversity peaks in the tropics, notably Asia, where genera like Leptocorisa include economically significant pest species targeting rice crops. Key genera illustrate the family's taxonomic breadth. The type genus Alydus is primarily Holarctic, with species adapted to temperate environments. In the Indo-Pacific, Dulichius (Micrelytrinae: Micrelytrini) features ant-mimetic species. Neotropical representatives include Hyalymenus (Alydinae), with around 20 species exhibiting specialized leg morphology. Regional patterns highlight uneven distribution. supports only about 10 species across a few genera, reflecting low temperate diversity. hosts 13 genera and 30 species, including 6 genera and 8 species in . Australia features endemic Alydinae genera such as Hamedius, Melanacanthus, and Riptortus, totaling 8 species. Taxonomic checklists are incomplete in regions like parts of the Neotropics and , with no major new genera described after 2020 despite ongoing revisions.

References

  1. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&anchorLocation=SubordinateTaxa&credibilitySort=TWG%2520standards%2520met&rankName=ALL&search_value=108249&print_version=SCR&source=from_print
  2. https://www.alice.cnptia.embrapa.br/alice/bitstream/doc/1055106/1/ID438122015LVcap18panizzi.pdf
  3. https://bugguide.net/node/view/97
  4. https://www.pubs.ext.vt.edu/content/pubs_ext_vt_edu/en/ENTO/ENTO-457/ENTO-457.html
  5. http://www.brisbaneinsects.com/brisbane_coreidbugs/Alydidae.htm
  6. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=108249
  7. https://core.ac.uk/download/pdf/195718833.pdf
  8. http://coreoidea.speciesfile.org/common/basic/Taxa.aspx?TaxonNameID=1186237
  9. https://bugguide.net/node/view/13648
  10. https://brill.com/edcollchap/book/9789004590601/B9789004590601_s004.xml
  11. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/alydidae
  12. https://uwm.edu/field-station/bug-of-the-week/lupine-bug/
  13. https://genent.cals.ncsu.edu/insect-identification/order-hemiptera-suborder-heteroptera/family-alydidae/
  14. https://sown.com.au/alydidae-broad-headed-bugs/
  15. https://www.britishbugs.org.uk/heteroptera/Alydidae/alydus_calcaratus.html
  16. https://academic.oup.com/aesa/article/103/5/706/10618
  17. https://www.vmnh.net/content/vmnh/uploads/PDFs/research_and_collections/the_insects_of_virginia/the_insects_of_virginia_no_9.pdf
  18. https://www.researchgate.net/publication/283641470_Broad-Headed_Bugs_Alydidae
  19. https://www.mdpi.com/2075-4450/13/8/750
  20. https://biodiversity.org.au/afd/taxa/ALYDIDAE
  21. https://doi.org/10.15560/12.5.1974
  22. https://www.aemnp.eu/data/article-1289/1270-50_2_425.pdf
  23. https://www.researchgate.net/publication/281450603_Leptocorisa_rice_seed_bugs_Hemiptera_Alydidae_in_Asia_A_review
  24. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1984&context=insectamundi
  25. https://academic.oup.com/aesa/article/101/3/558/8472
  26. https://www.mvtimes.com/2018/08/08/wild-side-broad-headed-bugs/
  27. https://www.cabidigitallibrary.org/doi/full/10.1079/cabicompendium.30366
  28. http://delphacid.s3.amazonaws.com/2022.pdf
  29. https://www.sciencedirect.com/science/article/pii/B9780128186213000057
  30. https://www.sciencedirect.com/science/article/pii/S0065280620300023
  31. https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/ENTO/ENTO-457/ENTO-457.pdf
  32. https://pmc.ncbi.nlm.nih.gov/articles/PMC8848042/
  33. https://animaldiversity.org/accounts/Alydus_eurinus/
  34. https://www.mdpi.com/2075-4450/11/6/347
  35. https://academic.oup.com/zoolinnean/article/83/4/371/2648652
  36. https://pmc.ncbi.nlm.nih.gov/articles/PMC9515603/
  37. https://www.researchgate.net/publication/43265898_Attractant_pheromone_and_allomone_from_the_metathoracic_scent_gland_of_a_broad-headed_bug_Hemiptera_Alydidae
  38. https://onlinelibrary.wiley.com/doi/10.1111/jeb.14195
  39. https://www.tandfonline.com/doi/full/10.1080/19768354.2023.2272989
  40. https://pubmed.ncbi.nlm.nih.gov/28961730/
  41. https://onlinelibrary.wiley.com/doi/10.1111/1748-5967.12113
  42. https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2021.760368/full
  43. https://doi.org/10.1111/zsc.12353
  44. http://www.millerlab.net/uploads/5/0/8/9/50897145/forthman_et_al._2022.pdf
  45. https://pje-journal.com/api/files/view/1287423.pdf
  46. https://www.researchgate.net/publication/298871675_Key_to_the_genera_of_New_World_Alydidae_Hemiptera_Heteroptera
  47. https://www.mindat.org/taxon-7875.html
  48. https://pmc.ncbi.nlm.nih.gov/articles/PMC9409444/
  49. http://coreoidea.speciesfile.org/common/basic/Taxa.aspx?TaxonNameID=1186693
  50. https://www.researchgate.net/publication/363019903_First_record_of_the_bow-legged_bug_Hyalymenus_subinermis_Van_Duzee_1923_Hemiptera_Heteroptera_Alydidae_in_California_with_description_of_the_mimetic_immature_stages
  51. https://www.biotaxa.org/cl/article/view/12.5.1974
  52. https://www.researchgate.net/publication/335751881_Illustrated_identification_key_to_the_genera_of_New_World_Micrelytrini_Hemiptera_Alydidae_Micrelytrinae_with_description_of_two_new_genera_one_new_species_and_new_distributional_records
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