Leptodora

Invisible Water Flea

Species Guides

Leptodora kindtii(Glass Waterflea)

Leptodora is a of large, nearly transparent predatory cladocerans containing two : L. kindtii, widespread in temperate lakes across the Northern Hemisphere, and L. richardii, known only from eastern Russia. are among the largest planktonic cladocerans, reaching up to 21 mm in length, with approximately 98% transparency as a defense against fish . The genus is taxonomically isolated as the sole member of its Leptodoridae and suborder Haplopoda.

Pronunciation

How to pronounce Leptodora: //ˌlɛp.toʊˈdɔː.rə//

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Identification

Distinguished from other cladocerans by its large size (up to 21 mm), extreme transparency (about 98%), elongated , and reduced that covers only the pouch. Possesses six pairs of thoracic appendages forming a feeding basket, two large second for swimming, and a single large with approximately 500 spherically arranged that can move up to 10° in any direction. First antennae are in females but elongated in males.

Habitat

Pelagic zone of temperate lakes; occurs in freshwater environments with salinities below 4 psu. Found in oligohaline, intermediate freshwater, and stagnant freshwater sites in estuarine lagoons.

Distribution

L. kindtii: widespread across northern temperate lakes in North America (as far south as Texas and Oklahoma), Europe, parts of North Africa, northern Arabia, and Asia north of the Himalaya. L. richardii: known only from lakes in the Amur River basin of eastern Russia, including Lake Bolon.

Seasonality

peaks vary with local temperature conditions; in some systems, earlier peaks occur at warmer sites. Males appear only in autumn.

Diet

Voracious of small zooplankton, primarily cladocerans (Daphnia, Bosmina, Ceriodaphnia, Diaphanosoma, Diaphanosoma brachyurum) and copepods (Diaptomus, Cyclops). In some systems, small Diaphanosoma brachyurum (0.6–0.9 mm) are preferred prey. Prey captured through tactile encounter using mechanoreceptive setae on first thoracic limbs; prey is pushed into feeding basket formed by other thoracic limbs, , and .

Life Cycle

Females reproduce parthenogenetically for most of the year, producing a of every 12 hours. Eggs hatch into larvae approximately 2 mm long, progressing through six instars over 3–6 days (temperature dependent) to reach form at 6 mm. In autumn, parthenogenetically produced males appear; produces winter eggs that sink to the bottom and hatch the following spring as nauplius-like larvae.

Behavior

Prey capture initiated by chance encounter triggering a reflex in which the is brought forward to close the feeding basket. rate varies with temperature, prey , and size, ranging from less than one to 12 prey items per predator per day.

Ecological Role

Intrazooplankton capable of regulating prey ; at high densities, daily consumption can reach 100% of daily zooplankton production, substantially shaping grazing zooplankton structure. Important prey for fishes including whitefish, perch, ziege, and bleak. to parasitic Raphidascaris biwakoensis in some systems.

Human Relevance

L. kindtii is probably the only cladoceran ever described in a newspaper (Weser-Zeitung, 1844).

Similar Taxa

Bythotrephes longimanusCoexists with Leptodora in some lakes; both are large predatory cladocerans, but Bythotrephes has a distinctive long caudal spine and different body form.
OnychopodaSister group to Leptodora; differs in having branchial appendages on legs and different development.