1. Insect Reproduction Ch. 4 Introduction to Insect Biology and Diversity Tracey Anderson 12-01-2010

2. Reproductive Organs • Male Organs Courtesy of Dr. Ken Hobson, University of Oklahoma

3. Reproductive Organs cont. • Female Organs Courtesy of Dr. Ken Hobson, University of Oklahoma

4. Reproductive Organs cont. • Do the reproductive organs in insects resemble any other organisms? • What about humans (Homo sapiens)? Courtesy of http://www.1cro.com/Diversity/malerepro_1.gif Courtesy of http://www.health-res.com/EX/07-27-22/internalfemalepelvic.jpg

5. “The Universe is not only queerer than we suppose, but queerer than we can suppose " J.B.S. Haldane • It is not surprising that with the huge numbers of insects, evolution has produced many different reproductive avenues

6. Types of Reproduction • Oviparity • Generally what is thought of when considering insect reproduction • Most common form • Eggs are deposited after fertilization. Eggs’ nutrition comes from yolk • Used by most insect. Ex. Largest order of insect the beetles Information in the next sections are from the textbook and courtesy of Dr. Ken Hobson, University of Oklahoma Courtesy of http://denimpine.com/documents/pine_beetle_web1.jpg

7. Ovoviparity • Fertilized egg is held in reproductive tract of female until completely developed • Nutrition comes from yolk • Used by some beetles and flies Courtesy of Dr. Ken Hobson, Univ. of Oklahoma

8. Viviparity • Analogous to animal reproduction • Egg held in female productive tract like ovoviparity but nourished by mother • Some flies, aphids, earwigs, and some roaches Courtesy of http://www.insectsofalberta.com/images/2006-apr-3_earwig.jpg Courtesy of http://webdocs.cs.ualberta.ca/~games/aphid/gifs/aphids.gif

9. Parthenogenesis • Production of progeny from unfertilized egg • Asexual reproduction • Favorable in constant environment which natural selection is not necessary to help increase fitness • Production of males: bees wasps • Production of females: walking sticks Courtesy of http://www.animalpicturesarchive.com/animal/a7/New_Zealand_Walking_Stick-by_Tom_Pesendorfer.jpg

10. Paedogenesis • Unusual reproductive avenue used when resources are scare • Scarce resources caused larval ovaries to produce eggs which develop parthogenetically • Midge flies Courtesy of http://www.grahamowengallery.com/fishing/midge-2-large.jpg

11. Parthenogenesis • Offspring are genetically identical to parent • This is advantageous in a constant environment. Parent would be fit, so offspring would likely be fit, too • Natural selection would favor genetic diversity (sexual reproduction) in a changing environment

12. Parthenogenesis cont. • Bees (Order Hymenoptera) have a reproductive pattern known as “Haplo-diploidy” • Females are produced “normally” with union of egg and sperm • Males are produced from unfertilized eggs • Males would have 1 parent, 2 grandparents, 3 great-grandparents, 5 great-great-grandparents (interesting pattern, huh?)

13. Haplo-Diploidy and the evolution of sociality • It was once believed that the evolution of sociality in Hymenoptera was due to haplo-diploidy • Females were more closely related to sisters than to offspring • It was thought that it was more advantageous to look after sisters than to reproduce • Recently proven to be false