Scapteriscus didactylus (Orthoptera, Gryllotalpidae), predator of leatherback turtle eggs in French Guiana

Abstract

The present study describes the potential role of the insect Scapteriscus didactylus in egg mortality in nests of the leatherback sea turtle Dermochelys coriacea found in the Amana natural reserve in French Guiana. Out of the 3 mole cricket species (Scapteriscus didactylus (Latreille), S. borellii Giglio-Tos, Neocurtilla hexadactyla Perty) observed in the natural reserve, only S. didactylus was encountered on the sandy beaches where 4 species of marine turtles nest. Controlled experi- ments, in which S. didactylus individuals of various age classes and leatherbacks eggs were placed together, revealed that only the last instar nymphs of S. didactylus preyed on the eggs, making a characteristic round hole underneath the eggs in the sand. This same distinctive damage to eggs was seen in natural leatherback nests at Awala-Yalimapo beach in the Amana natural reserve. The pre- dation affected on average 18% (range: 3.6 to 40.0%) of all yolked eggs in the nests. Juvenile S. di- dactylus were present on the beach throughout the nesting season of leatherback turtles, while adult S. didactylus were observed when the nest density on the beach reached its seasonal maximum at the end of July.