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The "Arthropods" observatory was founded for TEMPO, and aims to standardize, sustain and develop monitoring approaches that have only been conducted on a local scale by a few laboratories until now. The observatory is broken down into two separate taxons, but problems, methods and challenges remain similar.

Forest insects

• Which species?

The insects section focuses on forest Lepidoptera. The main species is the pine processionary moth Thaumetopoea pityocampa, since it has become a model species for studying responses to climate change because of its geographical expansion and its phenology. Other species are considered but monitored more opportunistically, such as the boxtree moth Cydalima perspectalis (the only invasive species of this section), the larch budmoth Zeiraphera diniana and the oak processionary moth Thaumetopoea processionea. The pine and oak processionary moths, in addition to the defoliation of forestland, create important public health issues with their irritating hairs that cause skin and respiratory reactions.

The pine processionary moth completes one generation per year with larval colonies developing in winter, therefore the species is particularly sensitive to climate change. ONERC regards its range expansion as a bio-indicator of climate change, and the IPCC acknowledged it as one of the few undisputed distribution changes causally related to winter warming.

•  Why studying their phenology?

Marked phenological shifts have been observed more frequently in recent years among populations of the pine processionary moth, between climatically different regions as well as between years. More recently, an increase in local and intra-annual variability has also appeared, with populations of the same generation able to complete their larval development in autumn (early phenology) or spring (typical phenology). These changes extend the period of health hazards related to Lepidopterism, as exposure to irritating caterpillar hairs occurs particularly during pupation processions at the end of the larval development. The increased variability also makes the planning and use of control treatments more complex since those methods are often specific to different life stages. Understanding the phenological response of this species to climate change therefore represents major academic and applied challenges. It is therefore the subject of several ongoing research projects, some of which aim to standardise and automate methods for phenological monitoring of the larval and adult stages.

Mites - Ticks

• Which species?

The section on mites focuses on ticks, primarily Ixodes ricinus, which is most commonly found in woody environments and whose role in animal and human public health is important. It vectors many pathogens (parasites such as Babesia sp., bacteria such as the Borrelia sp. (Lyme), and viruses such as tick-borne encephalitis). The growth in high latitude and altitude of Ixodes ricinus and its American cousin (Ixodes scapularis) highlights the effects of climate change. Other new species in mainland France are starting to appear in monitoring, such as Hyalomma marginatum, another tick in the Ixodidae family, vector of Crimean-Congo hemorrhagic fever.

The Ixodes ricinus tick has a very variable generation period between two to five years depending on the weather. Its development and its activity are particularly dependent on temperature and moisture conditions.

• Why studying their phenology?

Ticks have an activity that varies a lot within a season because of changing weather conditions. Similarly, phenological variations between years are being observed. To better understand the phenology of Ixodes ricinus, we have standardized drag-based collection methods. Furthermore, temperature and moisture conditions are monitored and statistical models have been developed. A model was chosen to describe the activity of ticks based on previous weather sequences. Maps of weekly favourability for the activity of ticks can then be produced.

The knowledge and forecasting of tick activity help improve information and prevent the health risks associated with ticks.

Our current research is centred on improving the quality of forecasts and adapting the message according to the target audiences. 

Managers :

• Maurane BURADINO, Animatrice Insectes forestiers, UEFM, INRAE, Avignon, maurane.buradino@inrae.fr

• Mathieu LAPARIE, Animateur Insectes forestiers, URZF, INRAE, Orléans, mathieu.laparie@inrae.fr

• Karine CHALVET-MONFRAY, Animatrice Acariens/Tiques, UMR EPIA, VetAgro Sup, Marcy l’Étoile, karine.chalvet-monfray@vetagro-sup.fr