Identification of the Female-Produced Sex Pheromone of the Leafminer Holocacista capensis Infesting Grapevine in South Africa.

We report the first identification of a sex pheromone in a heliozelid moth, Holocacista capensis van Nieukerken & Geertsema. This leafminer recently infested grapevine in South Africa. Compared to solvent extraction of pheromone glands, solid phase microextraction (SPME) proved to be highly effective for collection of the pheromone from calling females. The volatiles collected by SPME were analyzed by gas chromatography with electroantennographic detection (GC/EAD). Three compounds eliciting electrophysiological activity from the male antenna were identified as (Z)-5-tetradecenal, (Z)-7-tetradecenal, and (Z)-9-hexadecenal by coupled gas chromatography-mass spectrometry (GC/MS). GC/MS analysis of dimethyldisulphide (DMDS) derivatives of fatty acyl moieties in pheromone gland extracts confirmed the presence of the corresponding putative pheromone precursors with double bonds in the same position and with Z geometry. Field trapping experiments in a South African vineyard confirmed that both (Z)-5-tetradecenal and (Z)-7-tetradecenal are essential for the attraction of male H. capensis, whereas addition of (Z)-9-hexadecenal to the blend did not affect the attractiveness. The composition of the pheromone is discussed in relation to the phylogeny of this family of moths.

A new leafminer on grapevine and Rhoicissus (Vitaceae) in South Africa within an expanded generic concept of Holocacista (Insecta, Lepidoptera, Heliozelidae).

A grapevine leafminer found recently in table grape orchards and vineyards in the Paarl region (Western Cape, South Africa) is described as Holocacistacapensis sp. n. It has also been found on native Rhoicissusdigitata and bred on that species in the laboratory. It is closely related to Holocacistasalutans (Meyrick, 1921), comb. n. (from Antispila), described from Durban in KwaZulu-Natal, but widespread in southern Africa and a native leafminer of various Vitaceae: Rhoicissustomentosa, Rhoicissusdigitata, Rhoicissustridentata and Cissuscornifolia. Holocacistacapensis has been found on Vitisvinifera both in Gauteng and Western Cape, the earliest record being from 1950 in Pretoria. The initial host shift from native Vitaceae to Vitis must have occurred much earlier. The species is sometimes present in high densities, but hitherto no sizeable damage to the crops has been noted. The genus Holocacista Walsingham & Durrant, 1909, previously known from the single European grapevine leafminer Holocacistarivillei (Stainton, 1855), is expanded and redescribed and for the first time reported from Africa, East and South-East Asia and Australia. It comprises seven named species and at least 15 unnamed species. The following species are also recombined with Holocacista: transferred from Antispilina: South-African Holocacistavarii (Mey, 2011), comb. n., feeding on Pelargonium, transferred from Antispila: the Indian species Holocacistamicrarcha (Meyrick, 1926), comb. n. and Holocacistapariodelta (Meyrick, 1929), comb. n., both feeding on Lanneacoromandelica, and Holocacistaselastis (Meyrick, 1926), comb. n. on Psychotriadalzelii. We also remove the following from Antispila: Heliozelaanna (Fletcher, 1920), comb. n. and Heliozelaargyrozona (Meyrick, 1918), comb. n., whereas the following Indian Vitaceae feeding species are confirmed to belong in Antispila s. str.: Antispilaargostoma Meyrick, 1916 and Antispilaaristarcha Meyrick, 1916. Holocacistasalutans and Holocacistavarii are redescribed and diagnosed against Holocacistacapensis and other South African Heliozelidae. DNA barcodes are provided for 13 species of Holocacista.

Occurrence and non-detectability of maytansinoids in individual plants of the genera Maytenus and Putterlickia.

Individual plants belonging to different species of the family Celastraceae collected from their natural habitats in South Africa (Putterlickia verrucosa (E. Meyer ex Sonder) Szyszyl., Putterlickia pyracantha (L.) Szyszyl., Putterlickia retrospinosa van Wyk and Mostert) and Brazil (Maytenus ilicifolia Mart. ex Reiss., Maytenus evonymoides Reiss., Maytenus aquifolia Mart.) were investigated for the presence of maytansinoids and of maytansine, an ansamycin of high cytotoxic activity. Maytansinoids were not detectable in plants grown in Brazil. Analysis of plants growing in South Africa, however, showed clearly that maytansinoids were present in some individual plants but were not detectable in others. Molecular biological analysis of a Putterlickia verrucosa cell culture gave no evidence for the presence of the aminohydroxybenzoate synthase gene which is unique to the biosynthesis of aminohydroxybenzoate, a precursor of the ansamycins including maytansinoids. Moreover, this gene was not detectable in DNA extracted from the aerial parts of Putterlickia plants. In contrast, observations indicate that this gene may be present in microbes of the rhizosphere of Putterlickia plants. Our observations are discussed with respect to the possibility that the roots of Putterlickia plants may be associated with microorganisms which are responsible for the biosynthesis of maytansine or maytansinoids.