Pseudococcyx tessulatana: an additional obstacle to the reproduction of thousand-year-old cypress trees in the Sahara?

The Saharan cypress (Cupressus dupreziana), endemic to the Tassili n’Ajjer plateau (Algeria), shows extremely low seed viability and a unique reproductive system (androgenesis), resulting in minimal recruitment. This study assessed whether cone-feeding insects represent an additional biotic constraint by identifying the causal agent and quantifying damage to cones and seeds. In November 2024, 147 mature cones were collected from 10 trees at three sites (Ingharohane, Ibendaraje, Amazar). Cones showing holes were individually caged to monitor adult emergence, then disarticulated to count insect-undamaged (apparently healthy) seeds; cones with black sporulation were also analysed to identify the associated fungus. Adults emerging from damaged cones were identified as Pseudococcyx tessulatana (Tortricidae). Overall infestation reached 30.61% of cones and differed significantly among sites, peaking at 55% in Amazar. Infested cones contained far fewer apparently healthy seeds (mean 54.36% in uninfested cones vs 17.98% in infested cones). In addition, 46.6% of insect-damaged cones showed a black mould identified as Aspergillus niger. This is the first confirmed record of P. tessulatana on C. dupreziana cones in its natural environment and documents substantial seed losses, with frequent association of A. niger, adding a further obstacle to reproduction.