THE REPRODUCTIVE CYCLES OF THREE VIVIPAROUS TELEOSTS, ALLOOPHORUS ROBUSTUS, GOODEA LUITPOLDII AND NEOOPHORUS DIAZI

¹ Biology Department, Grinnell College, Grinnell, Iowa

1. The reproductive cycles were determined for three goodeids: Alloophorus robustus, Goodea luitpoldii, and Neoophorus diazi. The study is based on a yearlong series of collections in the field; over 3000 females were examined.

2. Alloophorus and Goodea are shown to have a single cycle; young are born from June through August. Neoophorus probably has a multiple cycle and young are born continuously from April through January or February of the next year.

3. Brood size varies as follows: there are approximately 20 embryos per brood in both Goodea and Alloophorus but the average is about 40 in Neoophorus. Younger females have smaller broods although the difference is small.

4. Eggs are discharged from the follicle about time of fertilization and undergo all development within the ovarian lumen. On birth, young are able to swim actively.

5. There is no evidence of sperm storage or superfetation.

6. Embryos in any one brood exhibit much uniformity of size.

7. Abnormal development of embryos is at a minimum; runts constituted less than 1% of all embryos examined.

8. Neoophorus is believed to mature in one year whereas Alloophorus and Goodea are thought to take two years to develop to sexual maturity.

9. Major differences in the reproductive cycle between the three goodeids are believed to be primarily genetic in character.