Campoplex capitator Aubert, 1960

Scaramozzino, Pier Luigi, Giovanni, Filippo Di, Loni, Augusto, Ricciardi, Renato & Lucchi, Andrea, 2018, Updated list of the insect parasitoids (Insecta, Hymenoptera) associated with Lobesiabotrana (Denis & Schiffermueller, 1775) (Lepidoptera, Tortricidae) in Italy. 2. Hymenoptera, Ichneumonidae, Anomaloninae and Campopleginae, ZooKeys 772, pp. 47-95 : 47

Campoplex capitator Aubert, 1960 Figures 4, 5

Campoplex capitator : Marchesini and Dalla Montà 1992: 10, 1994: 205, 1998: 3; Dalla Montà et al. 1993; Coscollá 1997: 214; Colombera et al. 2001: 94; Marchesini et al. 2006: 12; Bagnoli and Lucchi 2006: 140; Marchesini 2007: 41; Lucchi and Santini 2011: 199; Loni et al. 2016: 131; Scaramozzino et al. 2017b: 132.

Campoplex difformis : Thompson 1946: 484.

Omorgus difformis Gmelin: Catoni 1910: 17, 1914: 250; Silvestri 1912: 295; Schwangart 1913: 6, 1918: 547; Ruschka and Fulmek 1915: 391; Leonardi 1925: 259; Boselli 1928: 189; Stellwaag 1928: 663.

Italian distribution of reared parasitoids.

Trentino-South Tyrol: Catoni 1910, 1914; Silvestri 1912; Schwangart 1913, 1918; Ruschka and Fulmek 1915.

Veneto: Marchesini and Dalla Montà 1992, 1994, 1998; Dalla Montà et al. 1993; Marchesini et al. 2006; Marchesini 2007.

Piedmont: Colombera et al. 2001.

Tuscany: Dalla Montà et al. 1993; Bagnoli and Lucchi 2006; Lucchi and Santini 2011; Loni et al. 2016; Scaramozzino et al. 2017b.

Campania: Silvestri 1912.

Sicily: Alcamo (TP), ex Lobesia botrana on grapes (ZSM new record).

Distribution.

Campoplex capitator is a Mediterranean species, occurring in the Iberian Peninsula, France, Corsica, Italy, Switzerland and Turkey ( Yu et al. 2012; Zwakhals and van Achterberg 2017). It is widespread in most of the southern European wine-growing areas ( Bagnoli and Lucchi 2006), although its presence on EGVM in Southern Italy was not definitely ascertained. Nuzzaci and Triggiani (1982), in Apulia, underline the presence of C. difformis on EGVM feeding on Daphne gnidium and the absence of C. capitator , as already stated by Silvestri (1912). When checking his collection in Naples, we found two series of specimens, both reported as C. difformis from L. botrana . Actually, the two series are composed of at least three different species:

1. Campoplex capitator from Portici (Naples), 5 females and 3 males, and from San Michele all’Adige (Trento), 3 females, 3 males and 1 individual without metasoma. The specimens from San Michele all’Adige have the same origin of those studied and published by Catoni (1910) with the name of C. difformis and identified by O. von Schmiedeknecht.

2. Diadegma stigmatellae Horstmann, 1980 ( Campopleginae), 6 males and 4 females from Portici, a parasitoid of Gracillariidae ( Shaw and Horstmann 1997).

3. Pristomerus vulnerator (Panzer, 1799) ( Cremastinae) 1 male and 1 female from Portici.

We are not sure if the two series of specimens correspond to those actually studied by Silvestri but we think that the Campoplex specimens he had attributed to Omorgus difformis belong to C. capitator .

In the Horstmann collection, as well as in the general collection of ZSM, we found 7 females and 6 males of C. capitator from Sicily (Alcamo, TP), emerged from larvae of L. botrana feeding on grapes in July 2007, August 2009 and late May-June 2010. Also in the Horstmann collection we examined a male and a female of C. capitator from Piacenza (Northern Italy), obtained from E. ambiguella .

Host range.

Campoplex capitator seems to have an extremely limited host range. It was discovered on EGVM for the first time by Coscollá (1980) in Spain. Yu et al. (2012) list only two host species, L. botrana and Ancylis mitterbacheriana (Denis & Schiffermüller, 1775) ( Lepidoptera Tortricidae ). According to Villemant et al. (2011), in French vineyards C. capitator lives mainly at the expenses of L. botrana and E. ambiguella , though it has been obtained occasionally also from S. pilleriana . All the mentioned hosts live mainly on the grapevine, with the exception of A. mitterbacheriana , an univoltine leaf folder which lives on deciduous woodlands and whose larvae feed on the leaves of beech, common hornbeam, oaks, and sweet chestnut ( Alford 2012, Brown et al. 2008).

Ecological role.

Campoplex capitator is a solitary koinobiont larval endoparasitoid. Its development is strongly synchronized with L. botrana : both species overwinter in the same places, and live in close association, the first at the expense of the larvae of all the moth generations. The female oviposits into the body of EGVM larvae of 2nd-4th instar ( Thiéry 2008, Villemant et al. 2011). Endophagous larva kills the host after spinning its own cocoon inside the moth cocoon. The larva of C. capitator builds a delicate elongated semi-transparent cocoon characterized by rounded poles, white color and a thin median opaque transverse line (Figure 4D).

The parasitization rates recorded in Europe (Italy excluded) are shown in Table 5, while those recorded in Italy are shown in Table 6.

Silvestri (1912) frequently found C. capitator on EGVM, both in Trentino (Northern Italy), in spring, and in Portici (Naples), from July to September. In Veneto (Northern Italy) it attacks all the generations of EGVM, with irregular and not particularly high rate of parasitism, often less than 1%, sometimes close to 12% in the first generation and 14% in the second and slightly more than 8% in the third generation ( Marchesini and Dalla Montà 1994, Marchesini et al. 2006); sometimes it is absent. In Piedmont, where EGVM developed 2 generations per year, Colombera et al. (2001) recorded parasitization rates of 7.4% and 5.9%, respectively. In Tuscany (Central Italy), on grapevine, C. capitator is the most frequent species among larval parasitoids, showing a good parasitic activity throughout the region, mostly on larvae of the first two generations of the year ( Bagnoli and Lucchi 2006). In the Natural Reserve of San Rossore (Pisa, Tuscany), it is very frequent on Daphne gnidium , where it represents the dominant species in the parasitoid community of EGVM; attacking larvae of all three generations, it contributed for more than 58% of the total number of parasitoids found in 2014 and more than 73% in 2015, with an overall annual parasitization rate for 2014 next to 10% ( Loni et al. 2016).

In France, the rates of parasitism can be very high, especially in the EGVM first generation ( Villemant et al. 2011). In the vineyards of Valencia (Spain), C. capitator is the only larval parasitoid that plays a significant role in the control of EGVM, even if the total parasitism levels found in that region were low across all the three generations ( Coscollá 1997). In Douro Wine Region (Portugal), C. capitator is the second most abundant parasitoid of EGVM ( Carlos et al. 2013), representing the 11.8% of parasitoids obtained in 10-year surveys. In Turkey, the species is mostly widespread in the Aegean vineyards ( Koclu et al. 2005, Özsemerci et al. 2016).

Despite being considered one of the possible candidates for use in the biological control of EGVM, the knowledge about its behavior and its development are too limited and still some difficulties have to be overcome to develop an efficient mass rearing in bio-factory ( Bagnoli and Lucchi 2006). Nevertheless, a recent cooperation between Italian and Chilean entomologists seems very promising ( Lucchi et al. 2017).

Taxonomic notes.

Horstmann (1985) divided the Western Palaearctic species of the genus Campoplex in four species-groups: melanostictus (including the spurius-group), continuus, discrepans and difformis species-groups; later, the C. borealis species-group was added ( Horstmann 2012). Both Campoplex capitator and C. difformis belong to “difformis” species-group, which is characterized by occipital carina joining hypostomal carina at a right angle at the base of the mandibles (i.e., occipital carina turned outwards ventrally); slender body with apically compressed metasoma; hind tibia with the median outer part from yellowish red to reddish brown, and basal part not clearly brightened; ovipositor sheath relatively long (at least as long as the hind tibia). Horstmann (1985) describes the female of C. capitator as follows in the key: body size approx. 5 mm, face wider than long, temples behind the eyes narrow, the lines (as seen in profile from above) touching the outside of the eyes and temples usually intersecting in or behind the scuto-scutellar groove, antennal segments, in the last quarter, at least as long as wide, prepectal carina medially not significantly broader than ventrolaterally and not clearly notched, hind coxae black with hind femora predominantly red, ovipositor sheath 1.4-1.7 times as long as the hind tibia, second metasomal segment not more than 1.6 times as long as wide.

The females of C. difformis , which are very similar to those of C. capitator , in Horstmann’s keys are distinguished by: body size approx. 8 mm, face longer than wide, antennal segments, in the last quarter, much wider than long, and the area superomedia of propodeum wide, and not clearly separated from the area petiolaris; both areas are clearly depressed.

Villemant et al. (2011) pointed out that C. capitator has often been confused with C. difformis in the past and many reports of this species on EGVM should probably be related to C. capitator . The identifications of C. difformis made by Silvestri as well as those of Catoni are to be referred to C. capitator (see above). The record of Nuzzaci and Triggiani (see C. difformis ), whose specimens were identified by Horstmann, has to be considered correct.

Molecular-based studies indicate that C. capitator could be conspecific of C. formosanae Horstmann, 2012, a species reared on Enarmonia formosana in Germany ( Hunt and Kuhlmann 2007, Hunt et al. 2008). The species was identified as C. dubitator at first, but then recognized as a valid species by Horstmann (2012). Despite molecular differences between the two species were not significant ( Hunt and Kuhlmann 2007, Hunt et al. 2008), laboratory tests showed that C. formosanae was unable to develop on EGVM larvae and small but constant morphological characters have been found that lead to consider C. formosanae as a distinct species from C. capitator ( Hunt et al. 2008, Jenner et al. 2013).