Encarsia mollicellae Polaszek and Luft Albarracin, 2010

Polaszek, Andrew & Albarracin, Erica Luft, 2010, Two new Encarsia species (Hymenoptera: Aphelinidae) reared from eggs of Cicadellidae (Hemiptera: Auchenorrhyncha) in Argentina: an unusual new host association, Journal of Natural History 45 (1 - 4), pp. 55-64 : 60-63

publication ID	https://doi.org/ 10.1080/00222933.2010.520169
persistent identifier	https://treatment.plazi.org/id/EB52171B-1E7D-FFE7-FE9E-FC5BFEA8C760
treatment provided by	Felipe
scientific name	Encarsia mollicellae Polaszek and Luft Albarracin
status	sp. nov.

Treatment

Encarsia mollicellae Polaszek and Luft Albarracin sp. nov.

( Figure 3 View Figure 3 )

Description (holotype)

Male: 0.75 mm.

Colour. Head and body largely brown. Lower occiput and stemmaticum darker than the rest of the head ( Figure 3A View Figure 3 ). Antennae uniformly pale brown. Scutellum and distal side lobes paler than mid-lobe and axillae ( Figure 3B View Figure 3 ). Base of metasoma paler than remainder. Legs (except coxae) pale yellow. Fore wings very slightly infuscate below marginal vein.

Morphology. Antenna ( Figure 3F View Figure 3 ) with seven antennomeres, the flagellum with five, one fewer than is usual for the genus. Scape four times as long as wide. F1 globular, as wide as long. Lengths of F1–F 5 in the following ratios: 1: 1.2: 1.4: 1.4: 1.6. F1–F3 with an array of unusual sensory setae, sensilla and possibly glandular structures, as follows: F1 apically on inner side with several short thick setae, and two basiconic sensilla ( Figure 3E View Figure 3 ); F2 on inner side in apical half with a cluster of four basiconic sensilla in a recessed area of the flagellomere ( Figure 3E View Figure 3 ). Stemmaticum with distinct reticulate sculpture, frons laterally striate. Mandible with socketed peglike structure clearly present ( Figure 3D View Figure 3 ). Mid-lobe of mesoscutum with three pairs of setae and an additional asymmetrically positioned seta, side lobes with two setae each. Axillar setae placed on the suture beween axilla and posterior side lobe ( Figure 3B View Figure 3 ). Scutellum distorted in holotype, therefore relative positions of scutellar sensilla and setae unclear. Fore wing three times maximum width of wing disc, uniformly setose (no asetose area around stigmal vein). Marginal fringe 0.54 times as long as maximum width of disc. Basal cell with three setae arranged in a row. Submarginal vein with two small setae, situated close to the wing base. Marginal vein anteriorly with seven long setae. Tarsal formula 5-5-5. Mid-tibial spur as long as the shorter side of the mid basitarsus. Metasomal terga with the following numbers of setae: T1, 0; T2, 1; T3, 1; T4, 1; T5, 1; T6, 0. T5 and T6 with a pair of setae centrally. T7 with two setae, and with five rows of transverse denticles.

Female

Unknown.

Distribution

Argentina.

Host

Plesiommata mollicella (Fowler) Hemiptera : Cicadellidae .

Material examined

Holotype male. ARGENTINA: Tucumán, El Manantial, (E. Luft Albarracin M ◦ 8) ex eggs of Plesiommata mollicella 9–18 January 2006 ( IMLA).

Comments

Encarsia dalbulae and E. mollicellae are currently known only from male specimens. Male Encarsia are often extremely difficult to identify to species in the absence of conspecific females, and it is possible that both species described here represent previously described species that are known so far from females only.

It is extremely unusual for Encarsia males to be reared from insect eggs, a biology known for only two described species, E. boswelli and E. porteri . As stated earlier, E. porteri males are obligate ooparasitoids of a range of Lepidoptera eggs. Given that virtually all female Encarsia lay unfertilized (male) eggs into already parasitized whitefly hosts, laying an egg into a cicadellid egg, situated more deeply in the plant tissue, could require modifications to the ovipositor, particularly its length. It is probable, but by no means certain, that the hosts of the female E. dalbulae and E. mollicellae are whiteflies ( Aleyrodidae ). Encarsia boswelli develops in eggs of Plataspidae (Heteroptera) , with males emerging alongside their female siblings in the same egg mass ( Polaszek and Hayat 1990).

Biologically and in some morphological aspects, E. dalbulae and E. mollicellae are most similar to E. porteri . The males are certainly similar to males of E. porteri , having flagellomeres F5 and F6 fused, which is quite unusual in the genus. Encarsia porteri males differ, however, in several respects: the two components of the fused F5 and F6 are clearly discernible in E. porteri (and hence the fused antennomere is much longer than the others) whereas they form a single antennomere in E. dalbulae and E. mollicellae ; T6 and T7 have four (occasionally more) setae in E. porteri (two in E. dalbulae and E. mollicellae ). Myartseva and Evans (2007) established the E. porteri species-group for two species: E. porteri and E. neoporteri . The group is defined morphologically by having a short and broad phallobase, and by the presence of basiconic sensilla distributed along flagellomeres 2–5 (i.e. non-apically as in other Encarsia males). The former character does not appear to hold true for the two new species, but basiconic sensilla are present in both species on flagellomeres F1–F3 ( Figures 2A–D View Figure 2 , 3E View Figure 3 ). Hunter et al. (1996) showed conclusively that E. porteri males develop exclusively in Lepidoptera eggs, but according to Myartseva and Evans (2008) at least one male of the closely related E. neoporteri was reared from Bemisia tabaci (Aleyrodidae) . To further confuse the issue, a series of males identified as Encarsia porteri in NHM all bear label data that they have been reared from B. tabaci . It seems probable that there are yet more cryptic species awaiting discovery within this interesting species group.