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Biological control programmes involving Ooencyrtus pityocampae Mercet (Hymenoptera: Encyrtidae) have proved effective at reducing the damage caused by the pine processionary Thaumetopoea pityocampa Denis & Schifferm€ uller (Lepidoptera: Thaumatopoeidae). In this study, the biological variables that influence the parasitism of O. pityocampae on the new laboratory host Philosamia ricini Danovan (Lepidoptera: Saturniidae) have been investigated. Laboratory experiments were conducted under the conditions of 25 AE 1°C, 65 AE 5% R.H (relative humidity) and a photoperiod of 16 : 8 h (L : D = light : dark). The host egg age and parasitoid age are often regarded as being key factors influencing the emergence rate of O. pityocampae. The optimal age of host eggs for parasitization was 1-2 days, and the emergence rate was highest with 5-day-old female parasitoids. Thus, our results define the optimal conditions for the effective and economic rearing of parasitoids as follows: one 5-day-old female parasitoid per 50 (1-2)-day-old host eggs. The development time of O. pityocampae ranged between 19.5 and 22.6 days. Parasitoids that were exposed to bio-honey survived 10.5 times longer than those that did not receive supplemental food. O. pityocampae was reared for more than nine generations on the eggs of P. ricini. Consequently, P. ricini has been found as a suitable new laboratory host for the mass rearing of O. pityocampae for the use of biological control programmes against T. pityocampa in future.

The current climate change has marked impacts on the phenology of species, i.e. the timing of the various stages of their life cycle. Yet, to fully understand how phenological patterns can be modified according to changes in temperature regimes, it is of prime importance to rely on high quality historical data. Here, we propose a very valuable dataset including individual monitoring from pupation to adult emergence of 46 479 individuals of pine processionary moth (Thaumetopoea pityocampa) surveyed between 1970 and 1984 in southern France along an altitudinal gradient. As optional prolonged diapause occurs in this species, i.e. some individuals experience one or more years of diapause before emerging, the caterpillars sampled in any given year were monitored during up to 5 years. The goal was to give precise information about phenology in this species to further analyse its temporal patterns of variation. This dataset is unique by its richness and the type of data it contains. Phenology in the pine processionary moth is often monitored by the use of pheromone traps in the field, which does not provide all the necessary information, because it is then not possible to trace back the exact origin of the moth trapped, nor to characterise other steps of the life cycle. Moreover, as it corresponds to historical data dating back to the 70s and the 80s, the dataset provides a historical baseline of trends in the pre-warming period.

Abstract To investigate enemy pressure across the range of the pine processionary moth (Thaumetopoea pityocampa, Den. & Schiff.) as it spreads northwards in Europe because of climate change, a survey of 206 egg batches from historical and newly colonized areas at both the westernmost and the easternmost ends of the front was carried out in 2016–2018. Out of them, 97 egg batches were collected from nine locations in three regions in France and 109 from four localities in two regions in Bulgaria, both within historical and newly colonized ranges of the pest. The average number of eggs per batch collected in Bulgaria (226.6 ± 43.2) was higher than that in France (194.3 ± 50.1). However, the hatching percentage was higher in French samples, varying from 69.8 to 95.7, vs 49.8 to 85.2 per cent in Bulgarian samples. Four primary parasitoids (Ooencyrtus pityocampae, Baryscapus servadeii, Anastatus bifasciatus, Trichogramma sp.) and a hyperparasitoid (Baryscapus transversalis, found only in two regions of the historical range in Bulgaria) were identified. The oligophagous species B. servadeii was present at all sites within the historical range of the pest. In newly colonized areas, the impact of primary parasitoids on the host was distinctly low, suggesting that they lag behind the range expansion of pine processionary moth. In France, the most abundant species in the T. pityocampa parasitoid complex were B. servadeii in Ré Island and Orléans (97.3 and 87.4 per cent, respectively), and Trichogramma sp. (99.7 per cent) in a newly colonized locality in Fréhel. Ooencyrtus pityocampae prevailed in three of four Bulgarian localities (72.1 per cent in Sandanski, 89.7 per cent in Maglizh and 65.7 per cent in Sladak kladenets), whereas B. servadeii was the most abundant in Gega (75.4 per cent). Mortality of B. servadeii and O. pityocampae caused by the hyperparasitoid B. transversalis amounted to 4.8–6.2 per cent. The impact of predators on the pine processionary moth in the egg stage was negligible at most sites, reaching 12.5 per cent in only one site (Maglizh).

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