Macromia illinoiensis

Walsh, 1862

swift river cruiser, Illinois river cruiser

Species Guides

Macromia illinoiensis georgina(Georgia river cruiser)
Macromia illinoiensis illinoiensis(Illinois River Cruiser)

Macromia illinoiensis, commonly known as the swift river cruiser or Illinois river cruiser, is a in the Macromiidae. The aquatic larval stage has been extensively studied due to its interactions with the zebra mussel (Dreissena polymorpha), which frequently colonizes larval bodies. Research demonstrates that zebra mussel attachment impairs larval foraging , reducing prey capture and altering burying behavior. Mussel creates a positive feedback loop where colonized larvae bury more shallowly, increasing further colonization risk. These effects are -dependent and reversible when mussels are lost, typically at molting. The species' spans aquatic and terrestrial , making impacts from mussel colonization potentially significant for dynamics.

Macromia illinoiensis illinoiensis by (c) Nick Block, some rights reserved (CC BY), uploaded by Nick Block. Used under a CC-BY license.

Macromia illinoiensis by (c) Matt Muir, some rights reserved (CC BY), uploaded by Matt Muir. Used under a CC-BY license.

Macromia illinoiensis by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Macromia illinoiensis: /məˈkroʊ.mi.ə ɪˌlɪ.nɔɪˈɛnsɪs/

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

Images

Habitat

Aquatic freshwater ; larval stage occupies lakes and rivers where burying in sandy or soft substrates occurs. Habitat specifically includes water bodies invaded by zebra mussels (Dreissena polymorpha), which colonize larval .

Distribution

North America; specifically recorded from Vermont and broadly across the United States. Global presence indicated but primary distribution centered in North America.

Diet

Predatory; larval stage captures aquatic prey including mayflies (Hexagenia limbata documented as prey item). Prey capture occurs via sit-and-wait ambush strategy when buried with exposed, or active sprawling above substrate during night foraging.

Host Associations

Dreissena polymorpha - epizoic Zebra mussels attach to larval body; not in strict sense but physical attachment with negative consequences. Mussel loads lost at larval molting but accumulate quickly over final larval stadium.

Life Cycle

Hemimetabolous development with aquatic larval (naiad) stage and terrestrial stage. and final larval stadia described in behavioral studies. Larvae multiple times; attached zebra mussels are shed at molting events. Final larval stadium duration allows significant mussel accumulation.

Behavior

Larval burying involves burying into substrate with only exposed for and ambush . Bury time and depth are plastic traits: slower-burying individuals have higher mussel rates, and colonized individuals subsequently bury more shallowly. Night foraging involves sprawling above substrate with higher prey capture rates than daytime. Behavioral changes are reversible when mussel attachment is lost.