BIOL 1101 Lecture Notes - Lecture 12: Hemimetabolism, Myriapoda, Parthenogenesis
10 May 2016
School
Department
Course
Professor
Document Summary
All insects and myriapods are dioecious, many groups have parthenogenetic members (in which an unfertilized egg can develop), and most species lay eggs. Myriapods, like many of the chelicerates, rely on indirect fertilization (in which a sperm packet is handed from male to female). Insects use copulation, or direct fertilization, to achieve internal fertilization. Myriapods and primitive insects have incomplete metamorphosis, in which the young insect looks like a smaller version of the parent. These immature stages are called nymphs, and each nymph is a different instar. Advanced insects like the flies, beetles, wasps and butterflies undergo complete metamorphosis, with radically different larval, pupal, and adult forms. Because the larvae and the adult often feed on different resources (and the pupae usually don"t feed at all), the different life stages do not compete with one another. The sequence below shows a fruit fly egg, and then the first, second and third instar larvae, the pupa, and a newly emerged adult.
