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Title: Copula duration, insemination and sperm allocation in Anastrepha ludens (Diptera: Tephritidae)

item Thomas, Donald
item LEAL, SANDRA - Animal And Plant Health Inspection Service (APHIS)
item CONWAY, HUGH - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2014
Publication Date: 8/1/2014
Publication URL:
Citation: Thomas, D.B., Leal, S.N., Conway, H.E. 2014. Copula duration, insemination and sperm allocation in Anastrepha ludens (Diptera: Tephritidae). Annals of the Entomological Society of America. 107(4):858-865.

Interpretive Summary: Infestations of Mexican fruit flies in the USA are controlled by massive releases of sterile fruit flies that are produced at a production facility in south Texas. The effectiveness of the releases is monitored by close examination of all captured wild flies to determine their reproductive status: fertile or sterile, mature or immature, mated or not. Female fruit flies store semen in different organs within their bodies for insemination of their eggs just before laying. Organs called "spermatheca" are designed for long-term storage of semen so that a female can remain fertile for several weeks. However, another organ, called the seminal receptacle or ventral receptacle, is the organ directly involved in insemination. As such it is the first organ to receive semen during copulation, and the last to contain semen after weeks of egg-laying and the supply becomes depleted from the spermatheca. Therefore, examination of the seminal receptacle, rather than the spermatheca, is the most reliable way to determine if semen is present, and therefore the female has mated and is fertile. This information is important to program managers who must assure that the sterile factory flies are compatible with the invasive pest flies, and that adequate coverage and sufficient numbers of sterile flies are being released.

Technical Abstract: The juxtaposition and functional relationship of the sperm storage organs in Anastrepha ludens is described. The spermatheca squash technique has been used to determine mated status in tephritid fruit flies and thus as a measure of compatability and coverage for SIT programs. Female Anastrepha ludens have four seminal storage organs: three spermathecae and a ventral receptacle. By interrupting coitus at set intervals it is shown that the ventral receptacle fills first and after 15-30 min the spermathecae begin to fill. Among wild captured flies, all mature (gravid) females had semen in the ventral receptacle, but only 40-60% had sperm in at least one spermatheca. Therefore, examination of the ventral receptacle rather than the spermathecae alone is the more reliable method for determining mated status.