Paratelenomus anu Rajmohana, Sachin & Talamas, 2019

Rajmohana, Keloth, Sachin, James P., Talamas, Elijah J., Shamyasree, Mukundan S., Jalali, S. K. & Rakshit, Ojha, 2019, Paratelenomus anu Rajmohana, Sachin & Talamas (Hymenoptera, Scelionidae): description and biology of a new species of phoretic egg parasitoid of Megacopta cribraria (Fab.) (Hemiptera, Plataspidae), Journal of Hymenoptera Research 73, pp. 103-123 : 103

Paratelenomus anu Rajmohana, Sachin & Talamas sp. nov.

Figures 1-3 , 4-8

Description.

Body length. Female: 0.65-0.71mm. Male: 0.66-0.68mm.

Color. Body black to honey brown; first metasomal tergite slightly xanthic, weakly contrasting with posterior metasomal segments; antenna and legs yellow to brown; wings hyaline; wing venation brown.

Head. Frons mostly smooth with coriaceous sculpture dorsally; central keel attenuated dorsally, not bifurcating around median ocellus; submedian carina absent; orbital carina present; a single row of equidistant setae present along orbital carina; gena dorsally coriaceous, as on vertex, but smooth toward mandibular articulation; occipital carina incomplete medially; crenulae arising from occipital carina short; labrum pentagonal, slightly more than 2 × wider than long, apex bidentate medially; antennal clava 4-merous; claval formula A11-A8: 1-2-2-1; A5 in males with tyloid.

Mesosoma. Notauli absent to weakly present posteriorly; mesoscutum with coriaceous sculpture; parapsidal lines present; mesoscutal humeral sulcus and mesoscutal suprahumeral sulcus indicated by cells; transscutellar articulation narrowed medially, wider and crenulate laterally; foveae of posterior mesoscutellar sulcus of uniform size; mesoscutellum abutting mesoscutum medially; disc of mesoscutellum semicircular, with coriaceous sculpture; setal bases on mesoscutellum simple, not pustulate; metascutellum rugulose; mesopleural carina absent; intercoxal space narrow, not completely occluded by postacetabular and mesopleural epicoxal sulci; acetabular field small, finely setose, and coriaceous; episternal fovea present; femoral depression weakly indicated; prespecular sulcus present; metapleural triangle present; metapleural carina present; paracoxal sulcus absent; posterodorsal metapleural sulcus present.

Metasoma. T1 longitudinally costate, with two lateral setae; T2 striate, striae absent in lateral and posterior portions of tergite.

Male. Similar to female, except antennae filiform and metasoma with 8 external tergites and 7 external sternites.

Diagnosis.

Paratelenomus anu does not fully follow either lead of the first couplet in the key to species of Paratelenomus by Johnson (1996) because the notauli are weakly present at the posterior margin of the metasoma (best seen in anterodorsal view) and may appear absent. Otherwise, P. anu matches the second lead based on the medially narrowed transscutal articulation and the presence of just two lateral setae on T1. By following the second lead of the couplet one would arrive at P. saccharalis , which is morphologically very similar to P. anu . They can be separated by the notaulus, which is well developed in P. saccharalis and extends for more than half the length of the mesoscutum; the central keel, which does not bifurcate around the median ocellus in P. anu ; and the interorbital space, which in P. anu is 1.25 × eye height and in P. saccharalis is slightly less than eye height.

Etymology.

The species is named ' Paratelenomus anu ' because of its small size. (In Sanskrit ' Paratelenomus anu ' is the equivalent for the smallest unit of matter). The name is treated as a noun in apposition.

Material examined.

Holotype, female: INDIA: Kerala St., Malapparamba, near Providence College , 9.VI.2015, J. Sachin, ZSI/WGRS/I.R-INV.5069 (deposited in ZSIC) . Paratypes: INDIA: 17 females, 2 males, CNC494969-494970 (CNCI); 21987/H3-21999/H3 (ZSIC); ZSI/WGRS/I.R-INV.5070-5073 (ZSIC) .

Comments.

A central keel that dorsally bifurcates around the medial ocellus was listed by Johnson (1996) as a generic character for Paratelenomus and was used to distinguish it from Psix Kozlov & Lê. In P. anu , the central keel dorsally attenuates and does not bifurcate around the median ocellus and thus this character does not unambiguously separate Psix from Paratelenomus , although it remains useful for identifying other species of Paratelenomus . The other characters presented by Johnson (1996) remain valid for Paratelenomus and it is based on these that we are confident in the generic placement of P. anu : head and mesosoma without rugose-reticulate sculpture; mandibles narrow, sicklelike, unidentate and broadly overlapping; paracoxal and metapleural sulci absent.

Sequence analysis.

The CO1 sequence of Paratelenomus anu (KT896660.1) was analyzed using the online BLAST tool of NCBI for comparison with other sequences in the GenBank database. We found P. anu showed 85% sequence identity with P. saccharalis (KC778442.1) with 520/628 identities, and 7 gaps that accounted for about 1% of the total alignment length. This degree of sequence divergence is congruent with treatment of P. saccharalis and P. anu as separate species.

Parasitism.

The host eggs collected from all locations contained both parasitized and unparasitized eggs. In the laboratory, M. cribraria nymphs emerged from almost all unparasitized eggs within five days of collection, while the parasitoids emerged within 11-13 days. Male wasps were usually the first to emerge and remained on the egg mass for emergence of the females, with which they immediately mated for 12-15 sec. Following copulation, males continued waiting for the emergence of additional females. Among all the egg batches collected, the maximum number of males that emerged from an egg mass was four. Each egg mass had an average of 22.97 ± 6.41 eggs. The percent emergence of male and female parasitoids was 10.3 % and 63.2 % whereas the remainder (26.4%) were nymphs. This female-biased sex ratio enhances the potential of this parasitoid to be developed as a biocontrol agent against M. cribraria ( Ode and Hardy 2008) (Table 2 ). It was also observed in the laboratory that, immediately after mating, the parasitoid females mounted the dorsal abdomen of M. cribraria in the vicinity and remained phoretic.

Parasitoid efficiency.

The parasitism rate was 73.7 ± 7.3% for field-collected egg masses and 75.9 ± 3.5% for egg masses reared in the laboratory. Among the parasitized egg masses, nymph emergence was 10.39% for field-collected eggs and 7.58% in the laboratory (Table 2 ).

Figures

Figures 1 - 3. 1 Megacopta cribraria with phoretic Paratelenomus anu 2 female of P. anu on eggs of M. cribraria 3 individuals of P. anu prior to emergence from eggs of M. cribraria.

Figures 4 - 8. Paratelenomus anu 4 female (FSCA 00090272) mesosoma, dorsal view 5 holotype female (ZSI / WGRS / I. R-INV. 5069) lateral habitus 6 female paratype (CNC 494970), head, mesosoma, metasoma, dorsal view 7 female paratype (FSCA 00090272), head, anterior view 8 female paratype (CNC 494969), head and mesosoma, lateral view. Scale bars: in millimeters.