Southern High-Latitude Plant-Insect Interactions from the Miocene of Tierra del Fuego, Argentina

Abstract

Premise of research. The Miocene Punta Basílica Beds (northeast of Tierra del Fuego, Patagonia, Argentina) preserved a flora rich in insect herbivory traces. Here we document its insect damage and compare it with three Miocene floras from northwestern Argentina (low-latitude San José and Palo Pintado) and New Zealand (high-latitude Hindon Maar). In addition, comparisons are established for insect damage observed on Miocene Nothofagus in the Punta Basílica flora and the New Zealand Hindon Maar, Double Hill, and Kaikorai floras.Methodology. Plant-insect interactions were photographed and determined for 209 fossil leaves collected at the Punta Basílica locality. Leaves were censused for the presence/absence of functional feeding types.Pivotal results. Six functional feeding groups and 26 damage types (DTs) were recognized: hole (seven DTs) and margin (five DTs) feeding, skeletonization (six DTs), piercing and sucking (two DTs), mining (three DTs), and galling (three DTs). Nothofagus spp. are the most affected members of the paleoflora. Both of the low-latitude paleofloras compared have lower percentages of damaged leaves than the high-latitude ones; hole and margin feeding, mining, and skeletonization are recognized at all floras. Hole and margin feeding and skeletonization are recognized on Nothofagus leaves and are the most common functional feeding groups; hole feeding on Nothofagus is more prominent at Hindon Maar and Kaikorai than at Double Hill and Punta Basilíca. Additionally, Nothofagus specimens from Hindon Maar and Punta Basílica have evidence of mining, whereas galling is observed only on the New Zealand leaves. The Punta Basílica Nothofagus specimens are the only ones with piercing and sucking.Conclusions. Southernmost Miocene records of leaf herbivory worldwide and the first record from Argentine Patagonia are rich and comprise several functional feeding groups also observed in other Miocene paleofloras from the Southern Hemisphere. Clearly, multiple biotic and abiotic factors explain differences in the intensity of folivory. This report evidences the need for additional studies on herbivory at high-latitude floras.