The Oxycaryum cubense floating mat as refuge of Cornops aquaticum (Orthoptera: Acrididae), a new control agent of the water hyacinth

Abstract

Cornops aquaticum is a native Neotropic grasshopper frequently associated with Eichhornia (Pontederiaceae) spp. The aims of this research are: (1) to report the presence of this grasshopper on Oxycaryum cubense (Cyperaceae) in relation to climate conditions and microhabitat structure; and (2) to study and compare survivorship and occurrence of feeding and oviposition of C. aquaticum on O. cubense and the host plant (E. azurea). Grasshopper abundance was recorded during all seasons in both plants; field observations and no-choice tests were conducted to analyze the survivorship, feeding and oviposition of C. aquaticum on both plants. Results show that C. aquaticum is not able to feed and oviposit on O. cubense, but rather uses this macrophyte as refuge under specific climate conditions.

Keywords:

• Eichhornia
• Cyperaceae
• grasshopper abundance
• host specificity
• microhabitat selection

Acknowledgments

This research is dedicated to the late Joachim U. Adis, who was involved in coordinating and discussing this study and gave us many ideas for carrying out this manuscript. It is included in the International Project “Host-Insect Co-evolution on Water Hyacinth” (HICWA) initiated by Dr. Adis (Tropical Ecology Group of the Max-Planck Limnology Institute, Plön, Germany). Field trips and laboratory tests were funded by PICT 12755 FONCYT and PIP 6316 of CONICET. The stay at the Museum National d'Histoire Naturelle of the first author was supported by the Max-Planck Limnology Institute, Plön, Germany. We thank the anonymous reviewers and the Editor who improved the manuscript.

Notes

^†In memoriam