Meligethinae

C.G. Thomson, 1859

Pollen Beetles

Genus Guides

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Meligethinae is a of pollen beetles within the Nitidulidae, comprising approximately 700 described across about 50 . All species are associated with flowers or inflorescences of plants, with the vast majority feeding on dicots and approximately 7% on monocots. The subfamily is widespread in the Palearctic, Afrotropical, and Oriental Regions, but absent from the Neotropics and Antarctica. serve as effective of their host plants, including palms and various flowering crops.

Meligethes.viridescens.-.lindsey by James K. Lindsey. Used under a CC BY-SA 3.0 license.Meligethes-atratus-02-fws by Francisco Welter-Schultes. Used under a CC0 license.Musée entomologique illustré (6008703550) by Bisson-Cottard (Firm); Depuiset, A.; Fischbach, Gustave; Poteau, J.; Quartley, J.; Rothschild, J.; Specht, Friedrich; Vizetelly, Henry. Used under a Public domain license.

Pronunciation

How to pronounce Meligethinae: /ˌmɛlɪˈɡɛθɪˌniː/

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Identification

Meligethinae can be distinguished from other Nitidulidae by their specialized association with flowers and pollen-feeding . within the subfamily are often distinguished by subtle morphological characters including body shape, coloration, and particularly the structure of male and female genitalia. Some exhibit unusual secondary sexual characteristics, such as sinuate hind tibiae in both sexes of Cyclogethes tibialis, a feature rarely seen in the subfamily where tibial modifications typically occur only in males.

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Habitat

Associated with flowers and inflorescences of plants across tropical, subtropical, and temperate regions. Palm-associated inhabit male inflorescences of palms in Paleotropical regions. Other species occupy flowers of diverse plant including Rosaceae, Brassicaceae, Lamiaceae, and Asteraceae.

Distribution

Palearctic, Afrotropical, and Oriental Regions. Absent from the Neotropical Region and Antarctica. Specific records include China (Hubei, Sichuan, Yunnan, Tibet, Shaanxi, Ningxia), Southern Africa (South Africa, Namibia, Botswana), the Mediterranean (Italy, southwestern Alps), and Madagascar.

Diet

Pollen. Both larvae and feed on pollen within flowers or inflorescences of plants. Adults may also consume other floral parts.

Host Associations

  • Arecaceae - primary for palm-associated lineages; male inflorescences used by ~40 in ~10 include Chamaerops humilis, Phoenix reclinata
  • Rosaceae - larval for Meligethes and Odonthogethes Rubus idaeus is main for M. (O.) chinensis
  • Brassicaceae - larval for Brassicogethes; includes crop plants such as oilseed rapeDescurainia tanacetifolia is for B. salvan
  • Cleomaceae - larval for Brassicogethes
  • Lamiaceae - larval for Meligethes lugubris complex and Teucriogethesincludes Mentha, Thymus, Teucrium
  • Hydrangeaceae - unexpected for Lamiogethes acutuspreviously unknown for ; collected from flowers in Shennongjia, China
  • Asteraceae - possible for Cyclogethessuggested by indirect evidence; larval remain unknown
  • Restionaceae - for Restiopria biondiimale flowers of two Restionaceae ; only known for this
  • Sterculiaceae - probable larval for Meligethes pubescens -group Hermannia used by most in this group
  • Montiniaceae - suggested for Jelinekigethes danielssoniimportant clues suggest relationship; remains unconfirmed

Life Cycle

Larval development occurs within flowers or inflorescences of plants. Second instar larvae have been observed in male inflorescences of palms. The intimate association with floral tissues throughout development is a defining feature of the .

Behavior

actively visit flowers of the same , facilitating pollen transfer between plants. Adults have been demonstrated to serve as effective and important of host palms, providing services. Some species exhibit host fidelity, with approximately 80% of known species being monophagous or strictly oligophagous at the larval stage. Host shifts from dicots to monocots appear to have triggered rapid adaptive radiations in some lineages.

Ecological Role

Pollination of wild plants and crops. transfer pollen while feeding, supporting of plants including economically important crops such as oilseed rape. services provided through pollination of palms and other host plants. Some are considered minor agricultural pests when present in high densities on crops, though economic damage is often limited and plants can compensate for moderate bud damage.

Human Relevance

Pollen beetles in this contribute to pollination of agricultural crops, particularly Brassicaceae such as oilseed rape. Some are minor pests of oilseed rape when they feed on buds before flowering, though research indicates that neonicotinoid treatments targeting these beetles are rarely economically justified. The subfamily includes rare and such as Brassicogethes salvan, which has been proposed for IUCN Endangered status.

Similar Taxa

  • Other Nitidulidae subfamiliesMeligethinae is distinguished by obligate flower association and pollen-feeding ; other often associated with sap, fungi, or decaying plant matter
  • Other pollen-feeding beetlesFlower beetles (Scarabaeidae: Cetoniinae) and some longhorn beetles (Cerambycidae) also visit flowers, but differ in and are not confined to pollen as primary food source

More Details

Evolutionary history

Origin debated but likely Paleotropical around the Eocene-Oligocene boundary (approximately 35-40 million years ago). Palm-associated lineages represent more recent radiations (early Miocene-Pleistocene) through sequential evolution on pre-existing diverse palm rather than ancient . The palm-associated Meligethinus appears to be sister to the Meligethes complex based on molecular data.

Taxonomic notes

Recent revisions have described numerous new and , particularly from China and Southern Africa. Several genera erected in 2009 remain taxonomically problematic. The shows complex patterns of association that inform both and plant , as demonstrated by the correlation between Teucriogethes and Teucrium (Lamiaceae) evolution.

Conservation significance

Includes highly localized and rare such as Brassicogethes salvan, known from only a few specimens collected in the southwestern Alps over more than a century. This species has been proposed for Endangered status under IUCN criteria due to its restricted range and specific requirements.

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