LUKER, L.A.*; HATLE, J.D.; JULIANO, S.A.: The effects of photoperiod on the length of the oviposition cycle of the grasshopper, Romalea microptera
The reproductive tactics of many insects are affected by photoperiod because short-day photoperiods serve as a cue of the onset of winter. We tested several hypotheses regarding the effects of photoperiod on the length of the ovipositioncycle of the Eastern lubber grasshopper. We predicted that oviposition would occur sooner in short-day (11.5L:12.5D) animals versus long-day (13.75L:10.25D) animals because the short-day animals would be in a photoperiod associated with the Fall season. We also predicted that costs associated with earlier oviposition may be expressed as smaller size at the time of oviposition, fewer eggs, or smaller eggs for females on the short-day photoperiod. Two different diets (low and high food quantity) were tested at each photoperiod. The results indicate that the photoperiod did not have a significant effect on the timing of oviposition within either diet treatment. Females in the two photoperiod groups did not differ significantly in size at the time of oviposition in either diet treatment. In the high food treatment, there was no significant difference in the number of eggs between the two photoperiods. However, in the low food treatment, the short-day animals produced significantly fewer eggs than did the long-day animals. This suggests that shorter photoperiod can alter reproductive tactics when food is limited.