PARENT SESSION
Poster Session # 19: Insect and Invertebrate Ecology.
Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Preliminary analysis of some sense organs in the oviposition site selection of Sphenarium purpurascens.
Castellanos-Vargas, Iván*,1, Cano-Santana, Zenón *,1, 1 National Autonomus University of México, México City, Coyoacán, México
ABSTRACT- We analyzed the role of the tarsi, the antennae and the ovipositor of the grasshopper Sphenarium purpurascens (Orthoptera: Pyrgomorphidae) in the oviposition site selection related to a gradient of soil particle size and edaphic humidity gradient. We found that the blockade of the sensorial organs (F= 3.52, g.l.= 3, 24, P= 0.015) and the date of oviposition (F= 3.24, g.l.= 8, 24, P= 0.012) but not the interaction dates × treatment (F= 0.85, g.l.= 24, 451, P= 0.673) have a significant effect on the site selection related to the particle size gradient. The females with the blocked ovipositor selected particles with sizes below to 0.1 mm, while the selection made by females with the blocked legs and antennae did not differ from the selection of the control females. In both cases, they selected particles sizes between 0.2 to 0.35 mm. We found that the blockade of the sensorial organs (F= 238.64, g.l.= 3, 24, P<< 0.01) and the interaction dates × treatment (F= 2.47, g.l.= 24, 484, P= 0.00015), but not the date of oviposition (F= 0.29, g.l.= 8, 24, P= 0.959) have a significant effect on the site selection based on the edaphic humidity level. In this case, the selections made by the females with blocked antennae and ovipositor were soils with humidities value >60%, whereas the females of control and those of the blocked tarsi chose humidities below to 30%. We concluded that the antennae and the ovipositor of S. purpurascens have a central role in the oviposition site selection based on the humidity level. On the other hand, the ovipositor also is important on the site selection in a soil texture gradient. Finally, we demonstrated that the tarsi of the legs are the sensorial organ with less importance in the selection based on the texture and humidity soil traits.
Key words: Oviposition, Selection, Sphenarium purpurascens, Site