Macrosiagon

Hentz, 1830

wedge-shaped beetles

Species Guides

9

Macrosiagon is a of wedge-shaped beetles ( Ripiphoridae) containing more than 20 described . Species in this genus are of and bees. First-instar larvae (triungulinids) exhibit phoretic , attaching to insects for transport. The genus has a broad distribution spanning the Nearctic, Neotropical, Palaearctic, Oriental, and Afrotropical regions.

Macrosiagon by (c) Louise Woodrich, some rights reserved (CC BY), uploaded by Louise Woodrich. Used under a CC-BY license.Macrosiagon pectinata by (c) skitterbug, some rights reserved (CC BY), uploaded by skitterbug. Used under a CC-BY license.Macrosiagon limbata by (c) Louise Woodrich, some rights reserved (CC BY), uploaded by Louise Woodrich. Used under a CC-BY license.

Pronunciation

How to pronounce Macrosiagon: //ˌmækroʊsiˈæɡən//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Habitat

Restinga has been documented for M. octomaculata in Brazil. M. flavipennis has been recorded in urban areas in Chile. Specific habitat preferences for most remain poorly documented.

Distribution

Palaearctic, Oriental, and Afrotropical regions (including Azerbaijan, Nepal, Laos, Malaysia, Yemen, Eritrea, Saudi Arabia, Kenya). Nearctic region (United States, southern Canada). Neotropical region (Brazil, Chile).

Host Associations

  • Thynnidae wasp - phoretic triungulinid observed attached to wing
  • Ancistrocerus campestris - M. cruentum larvae reported to prey on larvae in nest

Life Cycle

Hypermetamorphic development with distinct larval stages. First-instar larvae (triungulinids) are active, mobile, and phoretic. and triungulinids have been found on plants (e.g., Paepalanthus polyanthus, Eriocaulaceae). Triungulinids attach to wings for to nests where later instars develop as .

Behavior

First-instar larvae (triungulinids) exhibit , actively seeking and attaching to winged Hymenoptera for transport to nests. This facilitates access to the stages of and bees that serve as hosts.

Ecological Role

of solitary and bees. Macrosiagon larvae develop within nests, consuming host larvae and provisions. of host Hymenoptera.

Similar Taxa

  • RipiphorusAlso in Ripiphoridae with wedge-shaped body form; distinguished by taxonomic characters in wing venation and genitalia

More Details

Nomenclatural note

Under ICZN rules, the name is feminine in gender (based on Greek 'siagon', jaw, feminine), though some recent publications have erroneously treated it as neuter.

Host plant association

First record of Eriocaulaceae (Paepalanthus polyanthus) playing a role in Macrosiagon bionomics; and triungulinids found on this plant in Brazil.

Tags

Sources and further reading