Opportunistic predation by carnivore mammals on females of pine processionary moths, Thaumetopoea pityocampa

Abstract

The pine processionary moth (Thaumetopoea pityocampa, PPM) is a major defoliator in Mediterranean pine forests, with broad ecological and socioeconomic impacts. While vertebrate predators of its eggs, larvae, pupae, and imagos have been well documented, predation on adult females by mammals has not been previously described. Here, we present the first evidence of opportunistic predation by generalist carnivores on PPM imago females. We collected and analyzed fecal samples of red foxes (Vulpes vulpes), stone martens (Martes foina), common genets (Genetta genetta), and European badgers (Meles meles) in several Spanish mountain ranges between 2022 and 2024. Morphological and molecular analyses revealed PPM eggs and anal scales in 19.1% of red fox and 11.3% of stone marten feces in Cazorla in 2022, with mean counts of 1773 and 680 eggs per feces, respectively. This predation likely results from the limited dispersal and ground activity of ovipositing females, making them accessible prey for opportunistic terrestrial carnivores. Further studies are needed to assess the frequency, spatial extent, and ecological significance of this phenomenon, as well as its potential role in integrated pest management strategies.