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The Biological bulletin (20374801235)

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The Biological bulletin (20374801235)

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Title: The Biological bulletin
Identifier: biologicalbullet91mari (find matches)
Year: [1] (s)
Authors: Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983
Subjects: Biology; Zoology; Biology; Marine Biology
Publisher: Woods Hole, Mass. : Marine Biological Laboratory
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library



Text Appearing Before Image:
Vol. 91, No. 3 December, 1946 THE BIOLOGICAL BULLETIN PUBLISHED BY THE MARINE BIOLOGICAL LABORATORY
Text Appearing After Image:
A STRONGLY INTERSEXUAL FEMALE IX HABROBRACON P. W. WHITING University of Pcmisyk-ania, Philadelphia, and the Marine Biological Laboratory, Woods Hole In the parasitic wasp Habrobracon fuglandis (Ashmead), diploid males have never shown any tendency toward intersexuality; they are as definitely male as their normal haploid brothers. When a "diploid male with female genitalia" was- found, it was therefore regarded with especial interest. The specimen, designated freak 994, developing from a heavily x-rayed (29,300 r) egg, occurred among the offspring of a treated wild type (stock 33) female crossed with an untreated lemon honey male (Experiment by A. R. Whiting. 1945). Freak 994 shows the heterozygous condition of the semidominant body color gene lemon inherited from its father. (Note light base of antennae in Figure 1.) The number of its antennal segments and its large ocelli are male characteristics. It was to be expected, therefore, that male reproductive reactions would occur. Several tests at different times failed to evince any response toward females although the specimen appeared healthy, drank honey water and lived for several days until fixed in Carnoy fluid. Since- it likewise failed to give any response (female) to caterpillars, its indifference was probably not due to its sex type but to some un- known factor. Because of the small "feminized" genitalia on the "male" body, freak 994 was at first recorded as a "diploid gynandroid male." (1\ nandroids, however, have always been haploids. They are mosaic males in which the two sexually different types of male tissue react in a complementary way to feminize the external genitalia (Whiting, Greb, and Speicher, 1934). Their mosaicism is shown by their asym- metry, not only in body color, in number of antennal segments, in mutant traits, and often in wing length, but especially in the external genitalia which are a mixture of normal male and feminized male structures with much reduplication and irregu- larity. In freak 994 there are no male genital structures and the female genitalia, consisting of a pair of sensory gonapophyses with no visible sting, are symmetrical and larger than in gynandroids. They are much smaller, however, than the female genitalia found in gynanders which are male-female mosaics with clearly separated male and female regions. That freak 994 is not a sex mosaic is shown by its symmetry in body coloration, in antennal flagella with nineteen segments in each and in length of wings and legs. Two types of intersexes have hitherto been reported in Habrobracon. (1) Gynoid, dependent upon a single mutant gene, is a weakly intersexual male, func- tioning normally as a male, but having certain external traits, including antennae, feminized. (2) Nine intersexual females were reported (Whiting. 1943) occurring in a single fraternity. "Superficially, these appear to be the reverse of the gynoid 243

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1825
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the biological bulletin
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