Pteromalus tethys Gijswijt, 1999

Delvare, G., Escolà, A. Ribes, Stojanova, A. M., Benoit, L., Lecomte, J. & Askew, R. R., 2019, Exploring insect biodiversity: the parasitic Hymenoptera, chiefly Chalcidoidea, associated with seeds of asphodels (Xanthorrhoeaceae), with the description of nine new species belonging to Eurytomidae and Torymidae, Zootaxa 4597 (1), pp. 1-90 : 73-75

Pteromalus tethys Gijswijt, 1999

( Fig. 32 )

Material examined. Type material. Paratypes (n = 4) (in ITZ).

Other material. FRANCE: Bouches-du-Rhône, La Ciotat , 36 m, 43.19861°N 5.63138°E, ex seeds of A. cerasiferus , 12.vi.2010, 13.vi.2011 and 28.v.2011 (H. Dumas) (7 ♀ 11 ♂, 3 ♀ 3 ♂ in RAPC) ; Corse, Aléria, Vaccaja , 20 m, 42.12861°N 9.46556°E, ex seeds of A. ramosus , 22.ix.2011, adults emerged 25.iv/ 15.v.2012, (J. Balajas) (51 ♀ 13 ♂, in GDPC) ; Dordogne, Belvès, Forêt de la Bessède , 232 m, 44.79361°N 0.90555°E, ex seeds of A. a. albus , 24.vi,2011 (R.R. Askew) (10 ♀ 7 ♂, 8 ♀ 3 ♂ in RAPC) ; La Douze, Forêt Domaniale de la Barade , 235 m, 45.03416°N 0.86028°E, 19.vi.2011, ex seed of the same asphodel and same collector, (73 ♀ 79 ♂, 13 ♀ 11♂ in RAPC) and collected on fruits, (11 ♀, in RAPC) ; La Jemaye , 52–131 m, 45.17°N 0.25666°E, 21.vii.2009, ex seed of the same asphodel (D. Simpson) (6 ♀ 4 ♂, in RAPC) ; Mouleydier, Forêt de Liorac , 127 m, 44.87778°N 0.62861°E, 17.vi.2011, (R.R. Askew) ex seeds of same asphodel, (1 ♀, in RAPC) ; Vergt, Le Lavadour , 212 m, 45.06111°N 0.71694°E, 25.vi.2011, same asphodel and collector, (7 ♀ 7 ♂, some in capsule with 34 ♀ 22 ♂ labelled ‘Dordogne, seeds collected vi.2011 R.R. Askew’) ; Pyrénées Orientales, Banyuls-sur-Mer, E Col de la Créu , 240 m, 42.46278°N 3.14222°E, ex seeds of A. ramosus ,. 6.vi.2011, adult emergence v.2012 (J. Lecomte) (3 ♀, in GDPC) ; Vienne, Châtellerault, Aire de Chagnats on A10, 131 m, 48.81778°N 0.54611°E; ex seeds of A. a. albus (R.R. Askew), 28.vii.2007, 4.x.2007, 22.vi.2008, 26.ix.2009, 14.xi.2009, 2.vii.2010 and 11.ix.2013, (24 ♀ 15 ♂, 4 ♀ 6 ♂ in RAPC) ; ITALY: Sicilia, San Fratello, Monte Nebrodi, N Casello Volpe , 1150 m, 37.94402°N 14.62579°E, on maturing flowers of A. ramosus (G. Delvare) (2 ♀, in GDPC) ; Vizzini, Monte Iblei, SE Lago Dirillo , contrado Rubalé , 350 m, 37.12103°N 14.72166°E, 22.vi.2014, on maturing flowers and from seeds of the same asphodel (G. Delvare) (46 ♀ 74 ♂, in GDPC) ; same locality, asphodel and collector, 420 m, 37.10778°N 14.72578°E (14 ♀ 33 ♂) ; same locality and collector, 350 m, 37.12103°N 14.72166°E, ex seeds of A. lutea , 19.vi.2014 (9 ♀ 12 ♂, in GDPC) ; same locality, asphodel and collector, SE Vizzini, Valle Paradiso , 600 m, 37.14727°N 14.80591°E, 21.vi.2014 (1 ♀ 2 ♂, in GDPC) ; GREECE: Peloponnese, Haraûgi , ex seeds of A. ramosus , 14.iv.2008 (H. Schnee) (2 ♂) ; SPAIN: Lleida, Tunel Viella , 1390 m, 42.67278°N 0.77333°E, ex seeds of A. a delphinensis, 18.viii.2008 (A. Ribes) (61 ♀ 42 ♂, probably in BMNH) ; TURKEY: Aegean sea Gökçe Ada Island, Şirinköy village , 62 m, 40.12944°N 25.73805°E, ex Asphodelus sp., 8.vi.2011 (A. Stojanova) (3 ♀ 2 ♂, in RAPC) ; Muğla, Milas, Bafa Lake , 28 m, 37.47644°N 27.48282°E, ex Asphodelus sp., 19.ix.2010 (A. Stojanova) (3 ♀ 1 ♂, in RAPC) .

Taxonomy. Pteromalus tethys was described from adults collected in the field in Cyprus, Corse, Greece and Spain ( Gijswijt 1999).

Recognition. Pteromalus tethys is close to P. vibulenus (Walker, 1839) from which it differs principally in having a relatively longer gaster, 1.7–1.9× as long as the mesosoma (1.2–1.5× in P. vibulenus ) with the last tergite rather variable in air dried material but at least 1.2×, up to about 2.0×, as long as its basal breadth. In the original description of the female of P. tethys , the fore wing is described as at least reaching the apex of the gaster, but in specimens examined, including two paratypes, the wings when folded back do not reach the base of the ovipositor sheath; in contrast, the folded wings of most female P. vibulenus reach or extend beyond the apex of the ovipositor sheaths.

Distribution and associated asphodels ( Figs 38 , 39–42 ). Pteromalus tethys is locally quite plentiful, emerging from samples of fruits and seeds of A. albus albus ( France: Vienne, Dordogne), A. albus delphinensis ( Spain: Lleida), A. cerasiferus ( France: Bouches-du-Rhône and Pyrénées-Orientales), A. ramosus ( Italy: Sicilia; Greece: Peloponnese) and Asphodelus sp. ( Turkey: Muğla). It was absent from large samples of A. cerasiferus fruits from Spain, our only Spanish records being from A. albus delphinensis high in the Pyrénées.

Biology ( Figs 39–42 ). Trophic relationships. Dissection of A. a. albus seeds revealed P. tethys to be an ectoparasitoid. Dead adult or pupal P. tethys were twice cut from seeds of A. albus containing, respectively, the remains of a larval eurytomid and a small lepidopteran larva (probably Cochylis epilinana ). Pteromalus tethys is itself attacked by E. confusus (see above).

Phenology. The life cycle of P. tethys is variable. On A. albus albus it is bivoltine. Fresh fruits collected in early summer, when still green, produce adult P. tethys after a short time, ripe fruits gathered late in July may soon yield a few adult P. tethys but most overwinter to emerge the following May, and dry fruits collected after mid-August produce P. tethys only in spring of the second year. In early June a few females, probably of the first generation, have been found with ovipositors inserted into green fruits of A. albus albus , but at the end of the month females presumed to be of the second generation occurred in numbers on the exposed seeds in brown, dehiscent seed capsules. P. tethys developing in fruits of A. albus delphinensis in the Spanish Pyrénées have a rather different phenology. A total of 49 adult P. tethys emerged in the first year from a sample of fruits collected in mid-August, 43 emerged the following May having overwintered once, 10 emerged in the third year and one in the fourth. This temporal spread of P. tethys emergence has been recorded only from A. albus delphinensis . Three males were collected on this plant on 6.vii.2007.

Sex ratio. Of a total of 363 Pteromalus tethys reared from all sources, 195 (54%) were females.

Figures

FIGURE 32. Pteromalus tethys Gijswijt, ♀ ex A. ramosus, Vizzini, Monte Iblei, Sicilia, Italy.

FIGURE 38. Distribution map of Eupelmus confusus, E. microzonus (only the occurrence of these two Eupelmus species on asphodels shown), Idiomacromerus asphodeli, Pteromalus tethys and Puklina depilata.

FIGURE 39. Trophic web of A. albus albus. Horizontal scale bars proportional to the numbers of reared specimens examined that are indicated in the bars. Arrows pointing out the direction of the trophic relationships: from phytophagous Bruchophagus spp. to the asphodel and from parasitoids to chalcid hosts.

FIGURE 40. Trophic web of A. albus delphinensis. Horizontal scale bars proportional to the numbers of reared specimens examined that are indicated in the bars. Arrows pointing out the direction of the trophic relationships: from phytophagous Bruchophagus spp. to the asphodel and from parasitoids to chalcid hosts.

FIGURE 41. Trophic web of A. cerasiferus. Horizontal scale bars proportional to the numbers of reared specimens examined that are indicated in the bars. Arrows pointing out the direction of the trophic relationships: from phytophagous Bruchophagus spp. to the asphodel and from parasitoids to chalcid hosts.The estimated number of Bruchophagus abscedus parasitized by P. depilata was estimated considering that a mean of 10 Puklina emerge from a larva of Bruchophagus.

FIGURE 42. Trophic web of A. ramosus. Horizontal scale bars proportional to the numbers of reared specimens examined that are indicated in the bars. Arrows pointing out the direction of the trophic relationships: from phytophagous Bruchophagus spp. to the asphodel and from parasitoids to chalcid hosts. The estimated number of Bruchophagus abscedus parasitized by P. depilata was estimated considering that a mean of 10 Puklina emerge from a larva of Bruchophagus.