Signiphora aleyrodis Ashmead, 1900

Woolley, J. B. & Dal Molin, A., 2017, Taxonomic revision of the flavopalliata species group of Signiphora (Hymenoptera: Signiphoridae), Zootaxa 4315 (1), pp. 1-150: 11-15

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Signiphora aleyrodis Ashmead, 1900


Signiphora aleyrodis Ashmead, 1900  

Figures 1–16 View FIGURES 1 – 4 View FIGURES 5 – 10 View FIGURES 11 – 16

Signiphora aleyrodis Ashmead, 1900: 412   . Female. Signiphora townsendi Ashmead, 1900: 412   . Female, male. NEW SYNONYMY Thysanus townsendi: Dozier (1933)   .

Thysanus aleyrodis: Peck (1951   , 1963).

Signiphora aleyrodis   : Nikol'skaya (1952); Rozanov (1965). Signiphora townsendi   : Nikol'skaya (1952).

Diagnosis. Fore wing marginal vein with seta M1 present; scutellum with 4 setae, antennal clava uniformly tan or light brown; Mt8 anterodorsal margin with a rounded medial incision; Mt1 length:Mt2 length usually 1.0.

This species is very similar to S. coquilletti   and although the two species are difficult to differentiate on the basis of structural characters or coloration, they appear to have different biologies and distinct allopatric distributions. Signiphora coquilletti   is known to occur in California, Texas, Florida, Baja California, and the Mexican states of Queretaro and Morelos. Signiphora aleyrodis   has been collected from Central America, the West Indies, and states in Mexico that can be considered Neotropical or at least southern coastal: Colima, Michoacan, Guerrero, Oaxaca, Chiapas, and Veracruz. Signiphora coquilletti   is uniparental (males are very rare); whereas S. aleyrodis   is biparental (males are common). As noted above, postovipositional web-spinning behavior has been observed only in S. coquilletti   , despite extensive collections of S. aleyrodis   (see below). Signiphora aleyrodis   typically has a longer Mt1 (Mt1:Mt2 = 1.00) than S. coquilletti   (Mt1:Mt2 = 0.50). The antennal clava of S. coquilletti   is often longer than for S. aleyrodis   , the ratio of clava length to scape length is 1.52–1.82 (mean = 1.64) in S. coquilletti   females and 1.15–1.75 (mean=1.47) in S. aleyrodis   females. The frons of S. aleyrodis   (between the ocelli and above the scrobes) is evenly and distinctly reticulate, whereas the frons of S. coquilletti   is transversely striate or imbricate, occasionally very weakly reticulate.

Description. Female. Length, anterior margin of pronotum to apex of epiproct, 0.37–0.74 mm (n=30). Vertex and frons red-orange, yellow-tan, or light brown, face and gena brown, clypeus dark brown. Antennomeres uniformly light brown or tan, antennal clava occasionally dusky brown in distal 1/2. Pronotum light brown, often yellow in lateral 1/4 or 1/6. Mesoscutum brown or light brown in anterior 1/2–2/3, lateral quarters often yellow.

Remainder of mesoscutum, scutellum, metanotum and propodeum light or pale yellow. Mt1 pale yellow, sometimes slightly darker than propodeum or light brown in posterior 1/2. Mt2 and Mt3 brown, Mt4 brown or occasionally yellow or brown in anterior 1/2. Mt5 and Mt6 yellow. Mt7 yellow, occasionally dusky brown in medial 1/3 or posterior 1/2 or entirely dusky brown. Mt8, epiproct and ovipositor sheaths dusky brown. Fore wing infuscated from base to distal end stigmal vein with usual hyaline areas at wing base ( Figs 5, 6 View FIGURES 5 – 10 ).

Head. Mandibular ducts enlarged apically; pedicel length:scape length 0.56–0.90; funicle with 3 anelli, the second 1.5–3× length of the first, the third 1.5–4× length of the first; clava length:scape length 1.15–1.75. Vertex posterior to ocelli finely and transversely striate or imbricate; frons (between ocelli and scrobes) finely but distinctly reticulate.

Mesosoma. Pronotum and mesoscutum transversely imbricate. Scutellum, metanotum, and medial sclerite of propodeum weakly imbricate. Scutellum with 4 setae (rarely 5) and 2 campaniform sensilla, medial propodeal sclerite rounded, the process on medial sclerite rounded or pointed apically. Fore wing length:width 2.8–4.3; fore wing LMS:fore wing width 1.2–1.9; marginal vein length:stigmal vein length 2.1–2.9; marginal vein with 6 dorsal setae and without ventral setae; seta M3 length:marginal vein length 0.44–0.74; apical end of costal cell between seta M1 and M2 or at seta M2. Hind wing with subparallel margins, length:width 6.9–9.8; hind wing width:fore wing width 0.33–0.54; LMS hind wing:hind wing width 2.3–3.8. Mesofemur with 1 long spine and 1 short spine on posteroapical margin; mesotibial spur with 3–7 teeth; mesotibial spur length:basitarsus length 0.81–1.10; basitarsus length:mesotibia length 0.41–0.58.

Metasoma. Mt1 strongly bilobed with medial portion transverse, rarely bilobed with medial portion rounded; Mt1 length:Mt2 length 0.5–1.0 (see discussion). Ovipositor with anterior-most portion lying under Mt3 or Mt4, occasionally under propodeum, Mt1 or Mt2; ovipositor length:metasoma length 0.50–0.98; ovipositor sheath length:ovipositor length 0.24–0.29; Ms3–Ms6 with anterior projections short to long; metasoma with Ms 6 in posterior 1/4 and with 6–10 setae; Mt8 with anterodorsal margin with a rounded medial emargination (sometimes with anterolateral margins produced medially, forming a closed or partially closed cell); Mt8 margin lateral to medial emargination transverse or produced slightly anteriorly.

Male. Length, anterior margin of pronotum to apex of epiproct, 0.32–0.63 mm (n=16). As described for female except as follows: antennal clava uniformly tan, not dusky in distal 1/2. Apex of metasoma yellow or pale yellow, without dusky brown areas. Clava length:scape length 1.17–1.64. Genitalia normal for flavopalliata   group, digitus without medial denticle but with a denticle at apex and a single seta at midpoint; digitus length approximately twice its width; Ms8 a transverse strip, without an anteromedial projection, extending to cerci laterally.

Discussion. In the lectotype and paralectotypes of S. aleyrodis   and the majority of specimens examined of both sexes Mt1 is strongly bilobed with medial portion transverse; however, rarely Mt1 is bilobed with the medial portion rounded. The lengths of Mt1 and Mt2 are generally subequal in both sexes, rarely Mt1:Mt2 = 0.5.

This species is best known from the extensive collections made by DeBach and Rose during exploration for natural enemies of Aleurothrixus floccosus (Maskell)   . Both of Ashmead's names S. aleyrodis   and S. townsendi   are available for this species; we choose S. aleyrodis   because the types are in better condition and because the name is descriptive of host relationships. It is quite possible that the species we are treating as S. coquilletti   , S. aleyrodis   and S. xanthographa   actually represent a complex containing additional cryptic species. Our concept of S. aleyrodis   includes material reared from whitefly in the Caribbean, Mexico and Central America, but it also includes several series from Brazil that fit our diagnosis for this species. However, other material from Brazil largely fits the diagnosis of S. xanthographa   (see redescription of S. xanthographa   for a list).

Type material. Signiphora aleyrodis   —LECTOTYPE ♀ [here designated]: in balsam, USNM Type 4855, TRINIDAD, West Indies, "bred from Aleurodes   [sic, Aleyrodes Latreille   ] on orange etc., w/6162". PARALECTOTYPES: 1 ♀ and 1 ♂, data as lectotype. Ashmead's type specimens are on one slide, USNM Type 4855, which was relabeled by Girault. The specimens are intact and in reasonably good condition for a balsam mount of this age. The female specimen to the left (slide oriented with red USNM type label to left and species name label to right) is here designated lectotype and the slide is labeled accordingly. Signiphora townsendi   — LECTOTYPE ♀ [here designated]: in balsam, USNM Type 4856, MEXICO, Tabasco, coll. T. Townsend, 19-VI- 1897, ex Aleyrodes   sp., on coarse grass. PARALECTOTYPES: 2 ♀, 1 ♂ in balsam, data as lectotype (USNM Type 4856). S. townsendi   was described by Ashmead (1900) from three female and one male specimen in Canada balsam on one slide, USNM Type 4856. The bottom center female on this slide (slide oriented with red USNM type label to the right) is here designated lectotype and the slide has been labeled accordingly.

Other material examined. BAHAMAS: 1 ♀, UCRC ENT 299149 View Materials ( UCR)   . BRAZIL: Amazonas: 1 ♂, 4 ♀, TAMU-ENTO X0460250, X0460251, X0460252, X0460254, X0460256 ( FSCA)   . BRAZIL: Distrito Federal: 2 ♀, TAMU-ENTO X0460239, X0460240 ( FSCA)   . BRAZIL: Sao Paulo: 1 ♂, 2 ♀, TAMU-ENTO X0616133, X0616134, X0616137 ( FSCA)   . COSTA RICA: San José: 1 ♀, TAMU-ENTO X0460245 ( FSCA)   . EL SALVADOR: 1 mixed series, 2 ♀, UCRC ENT 299160   -299162 (UCR). FRANCE: Guadeloupe: 2 ♀, TAMU- ENTO X0460253, X0460244 ( FSCA)   . HAITI: 1 ♂, 4 ♀, USNM ENT 763000, 763004-763007 ( USNM)   . HONDURAS: 6 ♀, TAMU-ENTO X0424826–X0424829, X0460242 ( TAMU)   ; TAMU-ENTO X0460243 (FSCA). MEXICO: Chiapas: 1 ♀, UCRC ENT 299151 View Materials ( UCR)   . MEXICO: Colima: 1 ♂, 3 mixed series, 3 ♀, UCRC ENT 299154–299156, 299159, 299171–299173 ( UCR)   . MEXICO: Guerrero: 8 mixed series, 3 ♀, UCRC ENT 299158, 299165, 299174–299182 ( UCR)   . MEXICO: Michoacán: 2 ♀, 1 host remains. UCRC ENT 299153, 299157, 299163 ( UCR)   . MEXICO: Oaxaca: 2 mixed series, 1 ♀, UCRC ENT 299166   –299168 (UCR). MEXICO: Veracruz: 4 ♀, UCRC ENT 299150, 299152, 299169–299170 ( UCR)   . PUERTO RICO: 8 ♀, TAMU- ENTO X0460237, X0460247, X0460248, X0460249 ( FSCA)   ; USNM ENT 763001–763003, 763009 (USNM).

Biology. This species is biparental and is commonly reared from whitefly of a variety of genera. Material collected by DeBach and Rose from Playa Azul, Michoacan, and Valle Nacional, Oaxaca, Mexico provides good evidence that S. aleyrodis   is hyperparasitic through Eretmocerus Haldeman   ( Aphelinidae   ) and Amitus Haldeman   ( Hymenoptera   : Platygastridae   ). In addition, DeBach and Rose collected this species in Mexico only in high-density whitefly populations in which several other parasitoid species were present (Rose, personal communication), a pattern typical of hyperparasitoids. Post-ovipositional web-spinning behavior such as described for S. coquilletti ( Woolley & Vet 1981)   has not been observed for this species, in spite of extensive observations of its behavior and of parasitized host material by DeBach and Rose on citrus in Mexico and in quarantine laboratories.


University of Newcastle


Carolina Biological Supply Company


University of California, Riverside


University of California


Florida State Collection of Arthropods, The Museum of Entomology


Ministry of Natural Resources


Smithsonian Institution, National Museum of Natural History


Texas A&M University














Signiphora aleyrodis Ashmead, 1900

Woolley, J. B. & Dal Molin, A. 2017

Signiphora aleyrodis

Ashmead 1900: 412