"This pathway has not been described in any other insect, and it may be a hallmark feature of butterflies that use a time-compensated sun compass," wrote the researchers. They also speculated that another such clock-related pathway of fibers they detected between two regions of the butterfly brain may play a role in regulating the insects' hormonal system, to induce the longevity that enables the butterfly to extend its survival in its overwintering grounds in Mexico.
The researchers include Ivo Sauman of the Czech Academy of Sciences; Adriana D. Briscoe of the University of California, Irvine; Haisun Zhu, Dingding Shi, Quan Yuan, Amy Casselman, and Steven M. Reppert of the University of Massachusetts Medical School; Oren Froy of the University of Massachusetts Medical School (Current Address: The Hebrew University of Jerusalem); and Julia Stalleicken of the University of California, Irvine (Current address: University of Oldenburg). This work was supported in part by grants from the NIH, GAAVCR, NSF and German Academy Exchange Service Grant, as well as the Volkswagenstiftung.
Sauman, I., Briscoe, A.D., Zhu, H., Shi, D., Froy, O., Stalleicken, J., Yuan, Q., Casselman, A., and Reppert, S.M. (2005). Connecting the Navigational Clock to Sun Compass Input in Monarch Butterfly Brain. Neuron 46, 457?67. http://www.neuron.org