Rutgers School of Environmental and Biological Sciences [Dept. of Entomology]

Wyeomyia smithii (Coquillett) 


by Wayne J. Crans, Rutgers University

 

Subgenus : Wyeomyia

Type of Life Cycle : Model for Wyeomyia smithii Type

Typical Habitat : Liquid within leaves of the Northern Pitcher Plant

Larvae Present : Year round

Head Hairs

Upper: Single

Lower : Single

Antenna

Length: Less than half as long as head

Tuft: Single, inserted on outer 1/4 of shaft

Abdominal Hairs (Segments III-VI) : 2 or more branched

Comb Scales : Single Row

Siphon

Index: 4.0 - 5.0

Tufts: Siphon covered with long single hairs

Pecten: Absent

Anal Segment

Saddle: Incomplete

Precratal tufts: None

Other

1) Tiny size

2) Two gills rather than four

GEOGRAPHIC DISTRIBUTION: Wyeomyia smithii belongs to the tribe Sabethini, a group of 12 mosquito genera that share more biological than taxonomic characteristics. The tribe is well represented in the New World tropics. Wyeomyia is the only sabethine genus that occurs in North America. Wyeomyia smithii has a distribution that extends from Newfoundland south to Delaware, west to northern Illinois and northwest into Saskatchewan. The mosquito's distribution corresponds to the range of the northern pitcher plant, Sarracenia purpurea gibbosa. Another pitcher plant mosquito, Wyeomyia haynei, is found in the southern pitcher plant, Sarracenia purpurea venosa, from Maryland to South Carolina. The range of the two pitcher plant mosquitoes does not appear to overlap. Wyeomyia smithii has been collected from 15 of New Jersey's 21 counties. The mosquito is most common on the outer coastal plain of southern New Jersey where pitcher plant habitat is abundant. The mosquito is less common in the northern counties of Sussex, Warren, Passaic, Bergen and Morris. Neither host plant nor mosquito have been found in Essex, Hudson, Hunterdon, Mercer, Somerset or Union counties.

SEASONAL DISTRIBUTION: Wyeomyia smithii is a multivoltine mosquito that completes its entire life cycle in the immediate vicinity of its predacious host plant. The females deposit their eggs directly on the water within the plant or just above the waterline in older leaves. The larvae live in the liquid of the plant and feed on the carcasses of insects and spiders being digested by the plant enzymes. Multiple generations take place from spring through fall. Late in the season, the females attach eggs to young leaves, before they become filled with water. The species overwinters as a larva frozen in a block of ice within the plant. The overwintering larvae pupate during the month of May and are usually on the wing by June.

LARVAL HABITAT: Wyeomyia smithii is an obligate inhabitant of the predacious pitcher plant and has never been reported from any other larval habitat.

COMMON ASSOCIATE SPECIES: None

LARVAL COLLECTION: Wyeomyia smithii larvae can be collected anywhere pitcher plants are found. Acid water sphagnum bogs in the New Jersey Pine Barrens support concentrations of pitcher plants in areas where the bog meets upland habitat. Virtually any stream that meanders through the pinelands will have scattered patches of pitcher plants along the banks. Larvae can be collected any time of the year. In summer, larvae can be aspirated from mature plants with a dropping pipette. In winter and early spring, larvae are most common in the younger, green leaves of the plant. Bringing a block of ice back from the plant will result in living larvae after the ice block has thawed. Field collected larvae will survive in distilled water but it is best to bring a portion of habitat water back with the specimens to use as an infusion for rearing purposes. Collectors are urged to use common sense and minimize environmental damage when sampling this scientific rarity.

LARVAL IDENTIFICATION: Wyeomyia smithii is an exceptionally small larva that is creamy white in color. The specimens lack pectin teeth and have the air tube covered with long single hairs. Wyeomyia smithii larvae have only 2 anal gills. The southern pitcher plant mosquito, W. haynei has the normal complement of 4. Living larvae obtain their oxygen directly from the water and rarely if ever come to the surface. Larval development is slow and specimens collected in the field during early spring may take many weeks to pupate under laboratory conditions.

REPRESENTATIVE COLLECTION RECORDS

Northern New Jersey

Location: Upper Greenwood Lake, Passaic Co.

Date: May 12

Habitat: Pitcher Plant

Instar : 3rd & 4th

 

Southern New Jersey

Location: Manahawkin Lake, Ocean Co.

Date June 14

Habitat : Pitcher Plant

Instar : All instars

IMPORTANCE: Wyeomyia smithii is a scientific curiosity that represents one of the wonders of the biological world. The tiny adult rests with its legs bent forward over its head in true sabathine fashion. The females even retain this odd posture in flight. The mosquito is autogenous deriving protein from the cadavers in the larval habitat. The mosquito can be used as a novel teaching aid but has no economic or medical importance.

©2008 Rutgers, The State University of New Jersey.
Last modified: 18 March 2013, lreed@rci.rutgers.edu.

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