PLANT-INSECT INTERACTIONS ON DICOTS AND FERNS FROM THE MIOCENE OF ARGENTINA

GNAEDINGER SILVIA C.; ROBLEDO, JUAN MANUEL; WAPPLER TORSTEN; PINHEIRO ESTHER

PALAIOS

SEPM-SOC SEDIMENTARY GEOLOGY

Lugar: Lawrence; Año: 2018 vol. 33 p. 338 - 352

0883-1351

The study of plant-insect interactions provides valuable information about the ecology of feeding behavior and the relationships between the host plant and the producer insect. Records of feeding traces are relatively rare for Miocene from South America. Here, we presented new records of plant-insect interactions on dicots leaves and fern fronds from Middle and Late Miocene of Argentina. We analyzed 1204 impressions corresponding with dicots and ferns were, 384 from San José Formation and 856 from Palo Pintado Formation. Traces of arthropod herbivory are found in 303 foliar impressions, 288 from Palo Pintado Formation and just 15 from San José Formation. We identified 44% of the traces on Thelypteris interrupta (Willd.) Iwatsuki 1963 (Thelypteridaceae), followed by Cedrela fissiliformis Anzótegui and Horn 2011 (Meliaceae) (15.1%) and Schinus herbstii Anzótegui 1998 (Anacardiaceae) (11.3%). T. interrupta presents a low diversity of Damage Types, indicating a monospecific relationship with the trace maker. On the other hand, the high abundance and diversity of Damage Types found on C. fissiliformis and S. herbstii denote that these plants were hosting a more diverse group of arthropods. Likewise, the lower number of traces identified in San José Formation would correspond to the xeric conditions established during the Middle Miocene in northwestern Argentina. These conditions changed at the Late Miocene, at least in some regions, to a humid climate, promoting an increase in phytophagy that is evidenced by the abundance recorded at Palo Pintado Formation.