Steven V. Sundberg, My Hanh Luong-Skovmand, Douglas W. Whitman
Journal of Orthoptera Research 10 (1), 39-51, (1 June 2001) https://doi.org/10.1665/1082-6467(2001)010[0039:MADOOA]2.0.CO;2
KEYWORDS: ovary, ovariole, oocyte, resorption body, oviposition, grasshopper, egg pod, fecundity, Acrididae, Romaleidae
We describe the development and appearance of Follicle Resorption Bodies (FRBs) and Oocyte Resorption Bodies (ORBs) in the grasshopper Romalea microptera (= guttata), and demonstrate that these structures can be used to determine the past ovipositional and environmental history of females. In R. microptera, one resorption body is deposited at the base of each ovariole following each gonotropic cycle. These structures are semi-permanent, and remain distinct for at least 8 wks and two additional ovipositions. Ovarioles that ovulate a mature, healthy oocyte, produce a cream-colored FRB. Ovarioles that resorb their oocyte, produce an orange-colored ORB. The number of FRBs equals the number of eggs laid, and the number of ORBs equals the number of oocytes resorbed. Healthy, well-fed R. microptera resorbed about a quarter of their developing oocytes. Starvation or other environmental or physiological stress increased the rate of oocyte resorption and thus increased the number of ORBs. By counting the number and type of resorption bodies in each ovariole, we determined the number of times a female laid, the number of oocytes resorbed, and the clutch size during each oviposition. These data were used to estimate the relative environmental stress experienced by laboratory females during each gonotropic cycle.
Oocyte resorption occurred frequently in 1° oocytes, and rarely in 2° oocytes. In healthy, well-fed females, oocyte resorption was temporally staggered, and thus the number of resorbing oocytes increased toward the end of each gonotrophic cycle. Adult virgin females maintained at low density with no male contact, resorbed fewer oocytes than females maintained at higher densities with males, suggesting that high densities or continual male harassment stressed females. In comparison to locusts, R. microptera were relatively slow to initiate oocyte resorption following starvation, requiring >12 d without food before massive resorption was detected.