Student Research Projects

Comparative Study of Ovipositor Morphology among Harvestmen (Gonyleptidae: Manaosbiinae)

Student Elizabeth Allen, '15 (Biology)
Emily Brooks '15 (Biology)
Margaret Tuthill '16 (Biology)
Faculty Mentor(s)
Department Biology
Course Biology 400: Scanning Electron Microscopy (SEM)

Abstract

The penis of laniatorean harvestmen represents an important source for taxonomic characters that are used to diagnose genera and species. Surprisingly, little is known about the external features of the female genitalia (ovipositor), especially for members of the gonyleptid subfamily Manaosbiinae. Thus, the general usefulness of features associated with the ovipositor for identifying species of harvestmen has yet to be determined. The purpose of this project was to compare the reproductive morphology of females representing 8 manaosbiin species. We dissected 27 ovipositors and prepared them for scanning electron microscopy. Ovipositors were dried, mounted on aluminum stubs, sputter-coated with gold, and examined with the Hitachi S3400N SEM at accelerating voltages of 5-20 kV. Our results indicate that species in this subfamily have ovipositors with four external lobes and 8-10 peripheral setae on the distal tip. Peripheral setae were cylindrical, consistently striated on the shaft, and curved at the end, terminating in a single, undivided distal tip. Peripheral setae inserted into sockets that were apart and undivided. Interspecific variation was observed with respect to the numbers and types of surface spines on the external surface of the lobes, varying from single spines with or without a split tip (usually associated with an adjacent pore) to double or triple spines. Overall, the ovipositors of harvestmen in the subfamily Manaosbiinae harvestmen were remarkably similar in external morphology, indicating that ovipositor morphology may be a good character for identifying the subfamily Manaosbiinae, but not for distinguishing genera or species.