Author(s):
Branco, Manuela 
; Santos, Márcia ; Calvão, Teresa ; Telfer, Gillian ; Paiva, Maria Rosa
Date: 2008
Persistent ID: http://hdl.handle.net/10400.5/5587
Origin: Repositório da UTL
Subject(s): araneae; arthropod diversity; larval nests; pines; Thaumetopoea pityocampa; understorey diversity
Description
1. In pine ecosystems, the role of the larval nests of the Mediterranean
defoliator Thaumetopoea pityocampa as shelter of other arthropods, was studied for the
first time. In Portugal, Pinus stands which differed in understorey plant diversity and
level of attack by T. pityocampa were compared.
2. The arthropod fauna found sheltering inside the nests consisted of 60 species,
representing 12 foraging types. Both arthropod richness and abundance were positively
correlated with nest size, expressed as larval biomass. Arthropod richness was further
positively correlated with understorey plant diversity, while no correlation was detected
between arthropod richness and nest density.
3. Spiders accounted for up to 50% of the species richness, while 80% of the individuals
collected were either juveniles, or females with brood, implying that T. pityocampa nests
are used for overwintering and brood care. Seventy-six per cent of the Araneae were
nocturnal ground foragers and specialised cryptic hunters, demonstrating the occurrence
of indirect interactions among species belonging to different communities, namely
ground vegetation layers and forest pine coppice.
4. It was concluded that, in Mediterranean pine ecosystems, T. pityocampa nests (i)
create habitat diversification and contribute to improve overwintering survival of a wide
range of arthropod species; (ii) play a functional role in the food web of pine ecosystems,
by promoting indirectly mediated interactions among species from different communities;
and (iii) do not contribute to create habitat for symtopic phytophagous arthropods,
since contrary to literature references for different types of shelters, 98% of the associated
species belonged to foraging types other than T. pityocampa.
