Philolema palanichamyi Narendran

Chuang, Angela, Gates, Michael W., Grinsted, Lena, Askew, Richard & Leppanen, Christy, 2019, Two hymenopteran egg sac associates of the tent-web orbweaving spider, Cyrtophora citricola (Forskal, 1775) (Araneae, Araneidae), ZooKeys 874, pp. 1-18 : 7-11

Philolema palanichamyi Narendran Figs 7 - 16

Re-description.

Based on female holotype ( Fig. 7 ; Fig. 8 : female from specimens reared during this study, not used in re-description). Length 2.2 mm. Body black except the following: scape, pedicel, apex femur, apex and base tibia (yellowish brown to brown), tarsus (golden), flagellum, mid coxa, femur, and tibia (brown). Ovipositor sheaths brown. Wings hyaline, setation pale. Venation golden.

Head ( Fig. 9 ). 1.43 × as broad as long, broader than mesosoma. Eye 1.08 × as long as malar space. POL 2.0 × as large as OOL; the latter 1.88 × as large as POD. Malar space 0.93 × as long as width of oral fossa and equal to height of eyes. Distance between toruli 1.0 × their own diameter. Adscrobal area subequal in width to acarinate antennal scrobes. Lower face striate, clypeus emarginate. Malar space with groove in dorsal half below eye, continuous with striation. Gena striate to umbilicate.

Antenna ( Fig. 10 ). Scape linear, 3.0 × as long as broad. Pedicel short, 1.29 × as long as broad. Funicle 6-segmented, setae decumbent. Fu1 1.30 × as long as broad, Fu2 just longer than broad, Fu3-5 quadrate. Funiculars with single row LS. Clava 2-segmented, 1.80 × as long as broad; bearing also the same pattern of LS as for the funiculars; segments fused, bearing two rows of LS.

Mesosoma ( Figs 11 - 13 ). 1.71 × as long as broad. Pronotal collar 3.60 × as broad as long; mesoscutum 1.25 × as broad as long; mesoscutellum 1.33 × as long as broad. Mesosoma dorsally umbilicate, interstices coriaceous. Notauli shallow, crenulate. Puncturation of mesoscutellum somewhat sparser than that of mid lobe of mesoscutum; mesoscutellum overhanging postscutellum. Axillar grooves crenulate, shallow. Postscutellum punctured mesally. Propodeum sloping at an angle of about 80° with main axis of mesosoma, evidently convex from side to side, with incomplete areolate stripe mesally delimited submedian ridges, on either side irregularly areolate; setation fine, erect and proclinate between the spiracles, dense very long and reclinate laterally; spiracle elliptic at posterior margin of metanotum. Tegula umbilicate. Prepectus with lateral panel glabrous. Mesopectus anteriorly depressed as scrobes to receive forecoxae, mesodiscrimen produced as beak-like prominence ( Fig. 13 , red arrow), scrobes glabrous anteriorly becoming coriaceous, adscrobal area umbilicate dorsally, coriaceous below; mesepisternum with femoral scrobe finely and densely reticulate; mesepimeron reticulate-carinate on ventral 1/3, with longitudinal carinae in dorsal 2/3. Metepimeron umbilicate, setae dense and long. Mesotrochantinal plate entirely sclerotized, its anterior carinate margin emarginate at mesofurcal pit. Metepisternum with lateral lobes anterad metacoxal foramina that overhang metafurcal pits.

Legs ( Fig. 13 ). Procoxa depressed anteriorly with diagonal carina delimiting depression ( Fig. 13 , blue arrow). Mesocoxa without lamella. Metacoxa bare dorsobasally, mostly coriaceous to finely reticulate.

Forewing ( Fig. 14 ). Setation fine and pale making wing appear sparsely setose, MV:PMV:STG as 20:25:19. Stigma with line of four sensilla placodea; parastigma bearing 3 adjacent sensilla placodea forming a triangle. Cubital and basal folds setose; basal cell with 3-6 irregularly distributed setae.

Petiole ( Fig. 15 ). In dorsal view just longer than broad, carinate anteriorly and produced anterolaterally as angulate processes, surface rugulose.

Gaster. Smooth dorsally, very faintly alutaceous laterally, just shorter than mesosoma, Gt4 longest tergum, ~2.0 × as long as Gt3. Gt1 and Gt2 asetose, Gt3 and Gt4 with a few setae dorsolaterally [some appear to have been abraded], Gt5 and Gt6 and syntergum more densely setose.

Male ( Figs 16 - 18 ). Similar to female in color and sculpture, differing in form of antenna and metasoma as below.

Antenna ( Fig. 16 ). Scape 2.11 × as long as broad, with smooth surface on protuberant ventral plaque bearing pores (visible under high magnification only) on apical two thirds. Pedicel 1.50 × as long as broad. Funicle 5-segmented with funiculars progressively shortening, each funicular with two whorls of long setae and a single row of LS visible; F1-3 asymmetric themselves progressively shortening; Fu4-5 symmetric, subquadrate. Clava 2-segmented, 2.30 × as long as broad.

Petiole ( Figs 17 , 18 ). 1.66 × as long as broad, slightly carinate anteriorly, its surface reticulate.

Gaster. Smooth dorsally, very faintly alutaceous laterally, somewhat shorter than mesosoma, Gt4 longest tergum, ~1.25 × as long as Gt3. Gt1 and Gt2 asetose, Gt3 and Gt4 with a few setae dorsolaterally [some appear to have been abraded], Gt5 and Gt6 and syntergum more densely setose.

Variation. Specimens vary greatly in size from approximately 0.8-2.5 mm total length. Prominence and extent of morphological characters diminishes with decreasing body size; for example, general body sculpture is less apparent in small specimens.

Material examined.

Holotype, ♀: INDIA: Timadu, Palani, 1992, coll. Palanichamy, Host Cyrtophora cicatrosa (spider); holotype, Desantisca palanichamyi ♀, sp. nov., det. Narendran 1983; B.M. TYPE HYM 5.3060; NHMUK013455729 (BMNH). Paratype, ♂: INDIA: Timadu, Palani, 1992, coll. Palanichamy, Host Cyrtophora cicatrosa (spider); paratype; Desantisca palanichamyi ♂ sp. nov., det. Narendran 1983 (USNM). Other material, SPAIN: Murcia: Murcia, 5.VI.2016, 37.9176N - 1.20633W, A. Chuang, Lot #593 (88 ♀♀, 15 ♂♂), Lot#971-16 (6 ♀♀); Málaga: Mál aga, 8.VI.2016, 36.73705N - 4.40486W, A. Chuang, Lot #609-1 (108 ♀♀, 25 ♂♂), Lot#956-16 (7 ♀♀), Lot #615 (16 ♀♀, 3 ♂♂); Cádiz: Cádiz, 13.VI.2016, 36.31301N - 5.8865W, A. Chuang, Lot #627-1 (27 ♀♀, 4 ♂♂); Cádiz, 16.VI.2016, 36.29552N - 6.0748W, A. Chuang, Lot #637-4 (14 ♀♀, 2 ♂♂), Lot#926-1 (8 ♀♀, 1 ♂); Tenerife: 28.07608N - 16.6483W, Lot#899-A (15 ♀♀, 4 ♂). All deposited in USNM.

Recognition.

This species can be distinguished from the widespread Philolema latrodecti Fullaway, 1953 by the suberect flagellar setation (females only, adpressed in Ph. palanichamyi ) and smaller ventral plaque (males only, less than half the depth seen in Ph. palanichamyi ). Usually, the sculpture of the tegula is much more distinct in Philolema latrodecti . Also, Ph. palanichamyi is known only from the eggs of Cyrtophora spp. while Ph. latrodecti is known only from the eggs of Latrodectus spp.

Biology.

Egg predator ( Fig. 17 ) of Cyrtophora spp. ( Araneae , Araneidae ).

Pediobius species group pyrgo

We examined 4♀♀ and 3♂♂ of a Pediobius species reared from C. citricola egg sacs collected by AC on Tenerife in the Canary Islands in May 2018. These specimens closely resemble material identified as Pe. pyrgo (Walker) from England and elsewhere in Europe reared from lepidopteran hosts as primary or very often secondary parasitoids. Only small and probably insignificant differences could be found. It seems best to regard the Pediobius material reared from Cyrtophora egg sacs collected in Tenerife as probably Pe. pyrgo until more material is available for morphological and molecular analyses.

As currently understood, Pe. pyrgo has been reported from an unusually broad range of primary hosts ( Noyes 2018) that it attacks directly or as a facultative hyperparasitoid. Lepidoptera are the most frequently recorded hosts, but Dermaptera , Diptera , and Hymenoptera have also been reported. Larvae or pupae from thirteen families of Lepidoptera , including leaf-miners, web spinners, case-bearers, as well as exposed feeders are known as hosts. However, in many instances it is their parasitoids that are attacked by Pe. pyrgo , especially ichneumonoid Hymenoptera but also other chalcidoids ( Eulophidae , Pteromalidae ).

Pediobius pyrgo is a solitary or slightly gregarious endoparasitoid of larvae and pupae, and it has been described as a koinobiont larva/pupal parasitoid of Leucoptera (Lep., Lyonetiidae ) ( Mey 1993). It is widespread in the Palaearctic and Oriental regions with a few New World records from North, South, and Central America. Schoeninger et al. (2015) record Pe. pyrgo as associated with Latrodectus eggs sacs in South America, and Pe. brachycerus (Thomson) and a few other species of Pediobius are known to be associated with spider egg sacs ( Bouček 1965; Noyes 2018), but these do not belong to the species group pyrgo .

Figures

Figures 7 - 8. Philolema palanichamyi 7 female holotype 8 female habitus. Scale bars: 1 mm.

Figures 9 - 16. Philolema palanichamyi 9 female, anterior head 10 female antenna 11 female dorsal mesosoma 12 female mesosoma, lateral 13 female ventral mesosoma 14 female fore wing 15 female petiole 16 male antenna.

Figures 17 - 19. Philolema palanichamyi 17 male petiole, lateral 18 male petiole, dorsal 19 Dissected C. citricola egg sac, blue arrow = dried, consumed spider eggs, red arrow = dead Ph. palanichamyi.