Student Research Projects

The Morphology of the Ovipositors of Cosmetid Harvestman

Student Kandace Gates ‘15 (Biology)
Faculty Mentor(s)
Department Biology
Course Biology 489: Research in the Natural Sciences

Abstract

The morphology of the ovipositors of cosmetid harvestman has only recently been explored using scanning electron microscopy (SEM). Results of several studies have indicated that the microscopic anatomy of ovipositors may represent a rich source for informative phylogenetic characters. This semester, I used SEM to observe the morphology of ovipositors for 16 species of cosmetid harvestmen from Central America. I dissected the ovipositors with the aid of a Leica stereomicroscope, ultrasonicated them for 1-2 min, and dehydrated them in a graded ethanol series. Specimens were dried using hexamethyldisilazane and sputter-coated with gold. Observations of the ovipositors revealed that most species had ovipositors with four external lobes (lacking surface denticles). The distal tips generally had 10 peripheral setae, with 8 in the ventral position and two located slightly more dorsally. Ovipositors exhibited significant interspecific variation with respect to the numbers and shapes of the distal tips of the peripheral setae. The results of my study will be incorporated into a much larger, comprehensive survey of the male and female reproductive anatomy of cosmetid harvestmen from Central America.