Signiphora merceti Malenotti, 1916

Woolley, J. B. & Dal Molin, A., 2017, Taxonomic revision of the flavopalliata species group of Signiphora (Hymenoptera: Signiphoridae), Zootaxa 4315 (1), pp. 1-150 : 79-82

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Signiphora merceti Malenotti, 1916


Signiphora merceti Malenotti, 1916 View in CoL

Figures 285–300 View FIGURES 285 – 288 View FIGURES 289 – 294 View FIGURES 295 – 300

Signiphora merceti Malenotti, 1916: 181 View in CoL . Female. Signiphora (Signiphorella) merceti: Mercet (1916) View in CoL . Signiphora merceti: Mercet (1927) View in CoL ; Peck et al. (1964). Thysanus merceti: Peck (1951) View in CoL .

Signiphorella merceti: Ferrière (1953) View in CoL .

Diagnosis. Body uniformly brown; fore wing and hind wing infuscated from wing base to apex; fore wing with demarcation between submarginal and marginal veins not distinct; fore wing marginal vein without setae M1 and M2, setae M3 and M4 small and subequal in length (or M4 slightly longer than M4); M3 length only slightly greater than maximum width of marginal vein.

S. merceti is most similar to S. jojobae , but can easily be distinguished from the latter by the lack of a medial emargination on the anterodorsal margin of Mt8 and by the infuscation on the fore and hind wings.

Description. Female. Length, anterior margin of pronotum to epiproct apex, 0.43–0.83 mm (n=13). Head uniformly light brown from vertex to gena. Antenna uniformly brown with clava dusky in apical 1/4–1/3. Body uniformly brown. Fore wing infuscated from base to apex with hyaline area in posterobasal 1/3. Hind wing lightly infuscated from base to apex.

Head. Mandibular ducts enlarged apically. Pedicel length:scape length 0.56–0.68; 3 anelli, the second from 2.0–3.0× length of first, the third from 3.0–5.0× length of first; clava length:scape length 1.32–1.48. Vertex and frons finely and transversely striate with scattered, minute punctations.

Mesosoma. Pronotum and mesoscutum transversely imbricate; scutellum, metanotum and medial sclerite of propodeum weakly imbricate. Scutellum with 5–8 setae and 0, 1 or 2 campaniform sensilla; medial propodeal sclerite rounded, process on medial sclerite rounded apically. Fore wing length:width 2.4–3.2× as long as wide; fore wing LMS:fore wing width 0.9–1.6; marginal vein length 2.1–2.8× stigmal vein; marginal vein with 4 dorsal setae (setae M1 and M2 absent) and without ventral setae; seta M3 length:marginal vein length 0.23–0.59; apical end of costal cell at seta M3 or proximal to M3. Hind wing with subparallel margins, 5.7–7.2× as long as wide, 0.37–0.50× fore wing width; hind wing LMS:hind wing width 2.14–2.87. Mesofemur with 1 long spine and 1 short spine in posteroapical margin; mesotibial spur:basitarsus 0.78–1.00; mesotibial spur with 3–6 teeth; basitarsus:mesotibia 0.37–0.46.

Metasoma. Mt1 bilobed with medial portion either rounded or transverse, Mt1 length:Mt2 length 2.0–3.0; ovipositor with anterior-most margins lying under Mt2–Mt4; ovipositor length:metasoma length 0.48–0.95; ovipositor sheath length:ovipositor length 0.17–0.22; Ms3–Ms6 with anterior projections short; Ms 6 in posterior 1/ 4 of metasoma and with 8–10 setae; Mt8 with anterodorsal margin transverse, without medial emargination, but often with lateral portions widely convex and produced slightly anterior to medial portion.

Male with coloration and sculpture as female. Length, anterior margin of pronotum to epiproct apex, 0.42–0.51 mm (n=2). Antennal clava length:scape length 1.33–1.41, scutellum with 6 setae and 2 campaniform sensilla, Mt1 strongly bilobed with medial portion transverse. Genitalia normal for flavopalliata group, digitus 2× as long as wide and with a single denticle at the apex (other details not visible in specimens examined); MS8 a transverse strip, extending to cerci laterally.

Discussion. Mercet (1916) erected the subgenus Signiphora (Signiphorella) to hold this species. Ferrière (1953) elevated Signiphorella to genus level. Although this species is distinct and highly autapomorphic, we know of no evidence to suggest that it represents a separate monophyletic clade worthy of subgeneric status.

Type material. In his original description, Malenotti (1916) stated only: "Habitat in Hispania. E Chrysomphalus dictyospermi Morg. exorta tria exempla vidi. Cl. entomologo Richardo Garcia Mercet reverentissime dicata." No further information regarding the repository was provided in the original description or in Malenotti's (1918) subsequent redescription, which may have prevented this specimen from being located so far. We believe that we have located and examined the holotype of this species. HOLOTYPE ♀ [examined]: slidemounted specimen in MNCN, labeled “tipo, Signiphora merceti Mal. [illegible], Santoña, 8-916” (MNCN_Ent No. Cat. 71293).

Other material examined. ALGERIA: 2 ♀, MHNG ENTO 0 0 0 0 9850 ( MHNG) ; BENIN: 1 ♀, BMNH (E) 990190 ( BMNH) . CHILE: 1 mixed series. USNM ENT 763091 View Materials ( USNM) . FRANCE: 1 sex unknown. MHNG 0 0 0 0 9852 ( MHNG) . ISRAEL: 2 ♀, BMNH (E) 990191, 990195 ( BMNH) . KENYA: 1 ♀, BMNH (E) 990192 ( BMNH) . MOROCCO: 1 ♀, MHNG ENTO 0 0 0 0 9851 ( MHNG) ; NEW ZEALAND: 4 ♀, NZAC 4048815, 4048993 ( NZAC) ; BMNH(E) 990193, 990194 (BMNH). SOUTH AFRICA: 1 ♀: UCRC ENT 299397 View Materials ( UCR) ; 4 ♀, 5 sex unknown at Calif. State Insectary : UCRC ENT 299398–299401, 299935–299939 . SOUTH AFRICA: Cape Province: 12 ♀, UCRC ENT 299389–299396, 299402–299405 ( UCR) . PORTUGAL: 1 ♀, USNM ENT 763095 View Materials ( USNM) . SPAIN: 1 ♀, USNM ENT 763094 View Materials ( USNM) . URUGUAY: Montevideo: 3 pinned specimens, 1 mixed series, 1 ♀, USNM ENT 763506–763508, 763089 , 763090 ( USNM) . USA: California: 117 slides with ♀ (number of individuals vary): USNM ENT 763086–763087, 763092–763093 , 763505 ( USNM) ; UCRC ENT 299146–299148, 299385–299388, 299406–299465 (UCR); BMNH(E) 990189, 990196, 990197 (BMNH.). CASENT 2212700–2212701 (CAS). TAMU-ENTO X0827963–X0828004 (TAMU). 6 immatures: TAMU-ENTO X0460315–X0460319, X0827962 (TAMU). USA: Louisiana: 2 ♀, USNM ENT 763085, 763088 ( USNM) .

Biology. Signiphora merceti is known to be uniparental ( Agekyan 1968; DeBach et al. 1958). No males have been observed in the very extensive collections from southern California. In fact, the only male specimens observed are the four from Carrasco, Uruguay (USNM ENT 00763090). This species is known to be a primary parasitoid of Diaspididae , most commonly species of Hemiberlesia , from which it is commonly reared in sympatry with S. flavella . Agekyan (1968) and DeBach et al. (1958) provided details of the biology on H. rapax and H. lataniae : eggs are deposited internally in mature female hosts, the 1 st instar larvae develop initially as internal parasitoids, but after 5 or 6 days the larvae chew through the host integument and continue development as external parasitoids. In spite of the numerous records of this species reared from California red scale, A. aurantii , we were not able to obtain oviposition by females placed on A. aurantii of various ages (2nd instar to adult females) in the laboratory.


Museum d'Histoire Naturelle


Universit� National du B�nin


Smithsonian Institution, National Museum of Natural History


University of Newcastle


New Zealand Arthropod Collection


University of California, Riverside


University of California














Signiphora merceti Malenotti, 1916

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

Signiphora merceti

Malenotti 1916: 181
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