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common name: waterlily leafcutter
scientific name: Synclita obliteralis (Walker) (Insecta: Lepidoptera: Crambidae: Acentropinae)

Introduction - Distribution - Description - Life Cycle and Biology - Hosts - Economic Importance - Related Species - Selected References

Introduction (Back to Top)

Hygrophila polysperma (Roxb.) T. Anderson (Polemoniales: Acanthaceae) is a rooted submersed or emersed aquatic plant in shallow water areas and saturated shorelines throughout Florida. This invasive aquatic plant also is known as hygrophila, hygro, East Indian hygro, green hygro, Miramar weed, oriental ludwigia, and Indian swampweed (hereafter referred to as hygrophila).

Hygrophila is a federal listed noxious weed (USDA 1983), a Florida state listed Category II prohibited plant (FLDEP 1993), and a Florida Exotic Pest Plant Council Category I invasive species (FLEPPC 2007). The submersed growth habit displaces native vegetation in many canals and drainage ditches in south Florida. The plant forms dense stands that occupy the entire water column, clogging irrigation and flood-control systems (Schmitz and Nall 1984, Sutton 1995) and interfering with navigation (Woolfe 1995). Hygrophila also creates problems as an emergent plant in some shoreline areas, including rice fields (Krombholz 1996).

In October 2007, we received a report from researchers at the UF/IFAS Center for Aquatic and Invasive Plants of an insect feeding on hygrophila. Samples of the insect were collected and it was identified as the waterlily leafcutter Synclita obliteralis (Walker). Of the more than twenty Acentropinae species occurring in Florida, Synclita obliteralis (Walker) is the most common. Although its common name implies that it is a pest of waterlilies, it actually has a wide host range. Most of the damage caused by the larvae usually is superficial and rarely endangers the plant, but the damage observed on the hygrophila plants was severe.

Hygophila showing feeding damage caused by the waterlily leafcutter, Synclita obliteralis (Walker).

Figure 1. Hygrophila showing feeding damage caused by the waterlily leafcutter, Synclita obliteralis (Walker). Photograph by J.P. Cuda, University of Florida.

Caterpillar of the waterlily leafcutter, Synclita obliteralis (Walker), attacking hygrophila.

Figure 2. Caterpillar of the waterlily leafcutter, Synclita obliteralis (Walker), attacking hygrophila. Photograph by J.P. Cuda, University of Florida.

Distribution (Back to Top)

This common moth occurs throughout Florida, westward to Texas and northward to western Nova Scotia and southern Manitoba (Munroe 1972). It also has been introduced into Hawaii (Williams 1944), England (Shaffer 1968), and British Columbia (Munroe 1972).

Description (Back to Top)

Eggs: The eggs are whitish in color, and appear domelike (oval and flattened). They are deposited singly or in overlapping, ribbon-like masses near the edges of submersed leaf surfaces.

Larvae: Most members of the crambid subfamily Acentropinae have aquatic larvae with tracheal gills. However, the larva of this moth lacks gills, and is sometimes referred to as "the sandwich man" due to its habit of living between two pieces of leaf (leaf case) it cuts from its host plant.

Waterlily leafcutter, Synclita obliteralis (Walker), leaf case.

Figure 3. Waterlily leafcutter, Synclita obliteralis (Walker), leaf case. Photograph by Lyle J. Buss, University of Florida.

The epidermis (skin) is covered with minute papillae (bumps), with body creamy-white, but increasingly brownish from abdominal segment four forward to the prothorax. The prothoracic coxae (proximal leg segments) are touching while the mesothoracic coxae are nearly touching. The head is yellowish-brown with a faint brown genal (cheek) stripe. The prothoracic spiracle (respiratory opening) is vestigial while spiracles on abdominal segments three and four are distinctly larger than others. The crochets (gripping hooks) are arranged in two biordinal (sometimes partially triordinal) transverse bands, with the anterior band distinctly larger than the posterior band.

Larva of the waterlily leafcutter, Synclita obliteralis (Walker), with opened leaf case.

Figure 4. Larva of the waterlily leafcutter, Synclita obliteralis (Walker), with opened leaf case. Photograph by Lyle J. Buss, University of Florida.

Pupae: No information is available about the pupae except that pupation occurs within the leaf cases.

Adults: Adults are sexually dimorphic and readily distinguishable. Females have a 15 to 19 mm wingspan, and the female's wings are paler in color appearing grayish-brown with orange-brown markings. The wingspan of the male is only about 11 to 13 mm, and the male's wings are grayish-brown interspersed with brownish and white markings.

Adult female waterlily leafcutter, Synclita obliteralis (Walker).

Figure 5. Adult female waterlily leafcutter, Synclita obliteralis (Walker). Photograph by J. Lotz, Division of Plant Industry.

Adult male waterlily leafcutter, Synclita obliteralis (Walker). Wingspan of this specimen is 11 mm.

Figure 6. Adult male waterlily leafcutter, Synclita obliteralis (Walker). Wingspan of this specimen is 11 mm. Photograph by L. J. Buss, University of Florida.

Adult male waterlily leafcutter, Synclita obliteralis (Walker).

Figure 7. Adult male waterlily leafcutter, Synclita obliteralis (Walker). Photograph by Lyle J. Buss, University of Florida.

Life Cycle and Biology (Back to Top)

Upon hatching, the larvae enclose themselves inside cut leaf pieces. Cases made by young larvae are water-filled and oxygen uptake occurs cutaneously (presumably via the epidermal papillae) whereas cases of older larvae are air filled. Larvae abandon smaller cases as they mature and construct larger cases from new leaves. The case may consist of two entire leaves, parts of leaves, or of parts of many plants tied together with silk. Prior to pupation, the larvae attach their cases to petioles or leaf blades of their host plants above or below the water surface, and spin their cocoons inside their cases.

Hosts (Back to Top)

Synclita obliteralis has a wide host range and is known to feed on nearly 60 plant species. The following plants arranged by families and genera are known to be hosts. The number of species, if more than one within each genus, is in parenthesis.

 

Acanthaceae: Hygrophila, Nomophila, Synema;

Alismataceae: Enchinodorus (3), Sagittaria;

Amaranthaceae: Amaranthus;

Apiaceae: Hydrocotyle (3);

Aponogetonaceae: Aponogeton (3);

Araceae: Orontium, Pistia;

Brassicaceae: Cardamine, Nasturtium;

Cyperaceae: Eleocharis;

Gentianaceae: Nymphoides (2);

Haloragaceae: Myriophyllum (2);

Hydrocharitaceae: Egeria, Elodea, Hydrilla, Limnobium;

Lemnaceae: Lemna, Spirodela;

Lythraceae: Rotala;

Marsileaceae: Marsilea;

Nymphaeaceae: Brasenia, Nelumbo, Nuphar, Nymphaea (7);

Onagraceae: Ludwigia (2);

Poaceae: Hydrochloa;

Polygonaceae: Polygonum (3);

Pontederiaceae: Eichhornia, Pontederia;

Potamogetonaceae: Potamogeton (3);

Salicaceae: Salix;

Salviniaceae: Azolla, Salvinia;

Scrophulariaceae: Ambulia, Bacopa, Lindernia, Micranthemum.

Economic Importance (Back to Top)

This insect frequently is a pest in aquatic plant nurseries, especially on waterlilies, Nymphaea spp.

Related Species (Back to Top)

Three other species of Synclita occur in the United States with one, S. tinealis Munroe, in Florida. The adult of S. tinealis is much smaller than that of the waterlily leafcutter and has longer, narrower and darker wings. The larvae of S. tinealis are not well known, but seem to feed on and most often make their cases of duckweed, Lemna sp.

The larvae of Munroessa gyralis (Hulst) and M. icciusalis (Walker) are similar to those of the waterlily leafcutter, but the anterior and posterior transverse bands of crochets are the same size. Munroessa adults are more brightly colored than Synclita and are yellowish-orange and white or brownish in color. Although Munroessa larvae may make portable cases, they usually cut only one leaf piece and attach it to a whole leaf and live between.

Selected References (Back to Top)