Submitted to: Florida Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/1/2001
Publication Date: 12/1/2001
Citation: Carpenter, J.E., Bloem, S., Bloem, K.A. 2001. Inherited sterility in Cactoblastis cactorum (Lepidoptera: Pyralidae). Florida Entomologist. 84(4):537-542. Interpretive Summary: The unintentional arrival of the cactus moth, in Florida has raised concerns for the safety of native and rare species of cactus in the Florida Keys and the potential spread of the cactus moth to areas of the western U.S. and Mexico. In addition to threatening the biodiversity of these native ecosystems, the negative publicity from such non-target effects could heighten public concern over the use of exotic natural enemies and jeopardize future weed biological control programs. Low doses of radiation can cause treated moths to produce sterile offspring. This type of induce-sterility is called inherited (F1) sterility. In this paper we report initial studies that investigated the response of the cactus moth to a wide range of radiation doses. Radiation-induced inherited sterility was observed at the lower doses. Inherited effects resulting from irradiation of males and females were expressed as reduced egg hatch, increased developmental time for eggs, and increased larval to adult mortality.
Technical Abstract: Newly emerged male and female adult cactus moths, Cactoblastis cactorum (Berg), were treated with increasing doses of gamma radiation and the moths were outcrossed to fertile counterparts. Fecundity of the moth pairs was not affected by increasing doses of radiation. The mimimum dose at which treated females were found to be 100% sterile when mated to untreated males swas 200 Gy. Fertility of treated males declined with increasing doses of radiation to approach 0 near 500 Gy. Inherited effects resulting from irradiation of P1 males and females were expressed in the F1 generation as reduced egg hatch, increased developmental time for the F1 egg, and increased larval to adult mortality. A shift in the F1 sex ratio in favor of males, as noted for other pyralids treated with radiation, was not observed.