Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 2, 2008
Publication Date: N/A
Interpretive Summary: Sapote fruit flies have been reported as occasional pests of citrus and have been found with alarming frequency in south Texas in recent years where the citrus industry is struggling to survive. Programs to control this insect must take into account their natural behavior, including their response to chemicals produced by males of their own species that function to attract females for mating. Identification of these chemicals is the first step toward learning about this behavior and attraction. In this work, we identified three chemicals produced by males during their courtship of females. One of the chemicals was identified for the first time as a natural product. It is hoped that the chemicals we identified can be used to develop an attractant for traps for this pest. The attractant has potential as a stand-alone lure or could be used in conjunction with other known attractants for this species. Traps baited with this lure would not only attract unmated females to their death, but also serve as a tool for detecting flies in areas subject to invasion by this pest.
Emissions from sexually active Anastrepha serpentine males were collected by solid-phase microextraction. Calling behavior of wild-type males showed no clear peak during the day except that calling was less frequent immediately after daybreak and just before dark. Calling by laboratory males was highest between 8-11 h after onset of photophase. Mating by wild flies occurred mostly between 6-10 h after onset of photophase. Two major components of male emissions were identified as 2,5-dimethylpyrazine (DMP) an 3,6-dihydro-2,5-dimethylpyrazine (DHDMP). DHDMP was identified by comparison to a synthetic standard with respect to GC retention and mass spectrum. A synthetic method for DHDMP is given. Emissions of these chemicals were greatest during peak calling behavior when males emitted up to 1.8 and 3.3 ug/h of DMP and DHDMP, respectively. A minor component that varied only slightly during the day was identified as 2,3,5-trimethylpyrazine. To our knowledge, this is the first report of 3,6-dihydro-2,5-dimethylpyrazine in nature.