Effects of Tepa on the Reproductive Organs and Embryogeny of the German Cockroach12

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Abstract
A rotary microtome was modified to inject precise amounts of tepa into German cockroaches, Blattella germanica (L.). Dosages of 0.9 μg produced sterility in males injected as 7th-instar nymphs, doses of 5 μg reduced the hatching of eggs laid by females as 7th-instar nymphs by 96%, and doses of 10 μg were toxic to nymphs of both sexes. Doses of 4 and 5 μg injected into adult males produced complete sterility but did not prevent the males from mating; the sperm were motile. Doses of 3–10 μg injected into females reduced the number of oöthecae produced, and only 4% of the females injected with 10 μg produced oöthecae; these females died while carrying the oöthecae. Hatch occurred at all dosages except 10 μg. Tepa stopped spermatogenesis and caused the testes to atrophy. Degenerative effects were first observed in the germarium and progressed until the sperm bundles were the only recognizable structures remaining in the sperm tubes. The basal oöcytes from females treated with tepa were significantly smaller than the oöcytes from females injected with solvent only. Tepa also caused abnormal oöcyte development and partial deterioration of the ovaries. Embryonic development was observed in eggs from unmated females, but various degrees of deformity were observed in some embryos. One fully developed embryo removed from an oötheca of an unmated female eventually became an adult female that failed to mate or reproduce. No unaided hatch was observed from oöthecae of unmated females. No hatch occurred from oöthecae formed by females mated with sterilized males. The degrees of embryonic development or deformity were within the range of those observed in eggs from unmated females.

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