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Contact with the setae of larvae (caterpillars) of pine or oak processionary moths could induce urticarial or allergic reactions in humans. These species are present in France and presently expanding towards highly populated areas due to climate change and/or human-mediated translocations. We aimed to describe the symptomatic cases of exposure to processionary larvae in France. We conducted a retrospective study of symptomatic cases of exposure to processionary larvae registered by the French poison control centres between 1 January 2012 and 31 July 2019. We reviewed all medical records coded with the agent "larvae". Of the 1274 included cases, 59% and 27% corresponded to pine and oak processionary larvae, respectively; the 14% remaining cases concerned unspecified processionary larvae. While the annual number of cases due to pine processionary larvae fluctuated during the study period, cases associated with oak processionary larvae increased steadily. Most of the annual cases occurred between January and May for pine processionary larvae, and April and August for oak processionary larvae (with a peak in March or June, respectively). Among the 1022 cases for which information was available, the sex ratio was 1.2 and the median age was 11 years old. Skin symptoms were reported by 96,3% of the cases, such as pruritus or urticaria. The severity was mild in 96.3% of cases, moderate in 3.5%, and severe in 0.2% (two cases). Ocular or oral exposures led more frequently to severe symptoms than dermal ones (respectively 31% and 18% vs. 2% of cases, p < 10−3). Since processionary moth larvae exposure is a growing health concern, which can cause severe injuries particularly after ocular or oral exposures, the population, and the professionals should be informed of existing recommendations to avoid exposure and measures to be taken after being exposed. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Context: Some forest insect pests are currently extending their range as a consequence of climate warming. However, in most cases, the evidence is mainly based on correlations and the underlying mechanism is not clearly known. Aims: One of the most severe pests of pine forests in Europe, the pine processionary moth, Thaumetopoea pityocampa, is currently expanding its distribution as a result of climate warming and does not occupy entirely its potential habitat. A model describing its spread was developed to simulate its potential range in France under various climate change scenarios. Methods: The spread model was divided into several sub-models to describe the growth, survival and dispersal of the species. The model was validated on the observed change of species distribution, its sensitivity was tested, and spread scenarios were simulated for the future. Results: The model shows that climate warming initiated the species range expansion in France since the early 1990s. The spread is now limited by dispersal capability, but human-mediated dispersal could accelerate the range expansion. Conclusion: Species range expansion is an indicator of climate change. However, time lags can appear due to limited dispersal capabilities, and human-mediated dispersal could create satellite colonies and artificially accelerate the spread. [ABSTRACT FROM AUTHOR]

Aim We investigated whether climate change has affected the potential feeding activity of a winter active larva, the pine processionary moth (PPM), Thaumetopoea pityocampa L., and whether it may explain its range expansion. Location The study area is France and, at a smaller scale, the Paris Basin. Methods We used a statistical model derived from Huchon and Démolin [1970 Revue Forestière Française (special issue: La lutte biologique en forêt), 220–234] to test whether their model, updated with climate change, could explain the observed range expansion. Since Battisti and colleagues have recently shown that climate could affect survival of the PPM through its effect on feeding activity, we also developed a mechanistic model based on larval feeding requirements (night air temperature above 0 °C and temperature inside the nest above 9 °C on the preceding day). We reconstructed the geographical distribution of feeding activity and we compared the resulting change with the PPM range expansion. Results The statistical model did not successfully predict the observed expansion but the mechanistic model showed considerable change in the feeding activity of the PPM. In the Paris Basin, the PPM border coincided with a zone unfavourable for feeding activity in the period 1992–96. Feeding conditions became more favourable in the period 2001–04, and the PPM succeeded in crossing this zone. Over larger temporal and spatial scales improved feeding conditions in the north-western part of France were forecast by the mechanistic model. Main conclusions (1) The range distribution of the PPM in the Paris Basin is no longer limited by unfavourable feeding conditions. (2) The pattern of range expansion of the PPM is now governed mainly by its dispersal capabilities and host tree distribution. (3) At the country scale, this approach gives an approximate prediction of the potential distribution of the PPM, though the model may not be reliable in mountainous regions. [ABSTRACT FROM AUTHOR]

The article analyzes the expansion of geographic range in the pine processionary moth, Thaumetopoea pityocampa, caused by the increased winter temperatures. The winter pine processionary moth, Thaumetopoea pityocampa , provides a classic example of an insect that is active in the winter, usually as a larva in the third and fourth instar. Latitudinal and altitudinal expansion areas for experimental investigations were selected in the Paris Basin, south of Paris, France, and in Venosta/Vinschgau Valley near Boizano/Bozen, northern Italy, respectively. In both France and Italy, natural gradients were utilized to simulate temperature conditions experienced by the insect, as spatial analogues for climate change. Larval activity of T. pityocampa at temperature around 0 degree Celsius was also observed by Fitz-gerald and Bias (2003), who monitored the movement events under field conditions and showed that, in induced colonies, larvae leave the nest with the onset of darkness and come back in the morning as long as the temperature is around 0 degree Celsius. Temperature conditions during both the precold period and the cold period influenced growth and survival of T. pityocampa at the expansion sites. The results indicate that while temperature during the pre-cold period significantly affects colony survival, it may have an even more important role during the cold period.

We present an annotated list of 11 Scolytinae and Platypodinae species newly or recently introduced to France. Four species are recorded for the first time as interceptions: Euplatypus hintzi (Schaufuss), Euplatypus parallelus (Fabricius), Xyleborus affinis Eichhoff and Xyleborus ferrugineus (Fabricius). Two are possibly naturalised: Xyleborus bispinatus Eichhoff and Cryphalus dilutus Eichhoff, while Cyclorhipidion distinguendum (Eggers) and Xyloterinus politus (Say) are confirmed as species newly established in Europe. Moreover, an unidentified species of Amasa Lea, collected previously in Spain, is recorded for the first time in France: Amasa sp. near truncata (Erichson). We point out that literature references to Amasa truncata as an invasive species in New Zealand and South America are incorrect, as the photographs of these non-native populations do not match the holotype of A. truncata. For each species we have updated its global distribution, detailed all French records, and summarized biology, ecology, host trees and potential risks as pests.

Mountain ranges may delimit the distribution of native species as well as constitute potential barriers to the spread of invasive species. The invasive pinewood nematode, Bursaphelenchus xylophilus, is a severe forest pest inducing pine wilt disease. It is vectored in Europe by a native long-horned beetle, Monochamus galloprovincialis. This study explored the potential of the Pyrenean chain to slow or prevent the natural spread of nematode-infested beetles from the Iberian Peninsula, where the nematode is established and is expanding its range, towards France and the rest of Europe. An analysis of the genetic structure and migration patterns of the beetle populations throughout the Pyrenean mountain range was combined with a spread model simulating the potential movements of nematode-infested beetles across it. The central part of the Pyrenees, which corresponds to the highest elevation zone, was shown to prevent gene flow between the French and Spanish populations of M. galloprovincialis on each side of the mountains. Conversely, strong admixture was detected between populations located on both sides of low elevation hills, and especially at the east and west extremities of the mountain range. Simulations of the spread of nematode-infested beetles under various thresholds of beetle survival and pine wilt disease expression gave results consistent with the variation in genetic make-up, suggesting that western and eastern hillsides may represent corridors favoring natural spread of the nematode from the Iberian Peninsula to France. Simulations also showed that temperature rise due to climate change may significantly reduce the extent of the barrier formed by highest elevations. Our results support the hypothesis that the Pyrenean chain represents a partial barrier to the natural spread of nematode-infested beetles. These results, which have to be considered together with potential human-assisted long-distance spread of the nematode, highlight priority zones for future pest monitoring and management programs. More generally, such an integrated approach could be used to assess the role of mountain chains in the potential spread of other invasive pests.

Recent climate change is known to affect the distribution of a number of insect species, resulting in a modification of their range boundaries. In newly colonized areas, novel interactions become apparent between expanding and endemic species sharing the same host. The pine processionary moth is a highly damaging pine defoliator, extending its range northwards and upwards in response to winter warming. Its expansion in the Alps has resulted in an invasion into the range of the Spanish moon moth, a red listed species developing on Scots pine. Pine processionary moth larvae develop during winter, preceding those of the moon moth, which hatch in late spring. Using pine trees planted in a clonal design, we experimentally tested the effect of previous winter defoliation by pine processionary moth larvae upon the survival and development of moon moth larvae. Feeding on foliage of heavily defoliated trees (>50%) resulted in a significant increase in the development time of moon moth larvae and a decrease in relative growth rate compared to feeding on foliage of undefoliated trees. Dry weight of pupae also decreased when larvae were fed with foliage of defoliated trees, and might, therefore, affect imago performances. However, lower defoliation degrees did not result in significant differences in larval performances compared to the control. Because a high degree of defoliation by pine processionary moth is to be expected during the colonization phase, its arrival in subalpine pine stands might affect the populations of the endangered moon moth., (© 2012 ISZS, Blackwell Publishing and IOZ/CAS.)

Many parasitic species of insects complete their entire development in seeds. They feed off storage reserves within the ovule. These reserves only normally accumulate in fertilized ovules. Consequently, female insects that oviposit their eggs directly into the plant ovule need to be able to select correctly, as unfertilized ovules of conifers normally become so-called empty seed. We provide clear evidence that in conifers, seed-parasitizing insects do not need to discriminate between fertilized and unfertilized plant ovules when ovipositing their eggs. A host-specific insect, the chalcid Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), lays its eggs in ovules of Douglas fir (Pseudotsuga menziesii (Mirbel) Franco) before fertilization has taken place in the plant. Oviposition not only prevents the expected degeneration and death of unfertilized ovules, but it induces energy reserve accumulation. Ovules that would otherwise develop as empty seed are redirected in their development by the insect to provide food for the developing larvae. Instead of the insect exploiting normal events during seed development, the insect manipulates seed development for its own reproductive advantage.