Introduction

During their postembryonic growth period insects pass through a series of stages (instars) until they become adult, the time interval (stadium) occupied by each instar being terminated by a molt. Apterygotes continue to grow and molt as adults, periods of growth alternating with periods of reproductive activity. In these insects structural differences between juvenile and adult instars are slight, and their method of development is thus described as ametabolous. Among the Pterygota, which with rare exceptions do not molt in the adult stage, two forms of development can be distinguished. In almost all exopterygotes the later juvenile instars broadly resemble the adult, except for their lack of wings and incompletely formed genitalia. Such insects, in which there is some degree of change in the molt from juvenile to adult, are said to undergo partial (incomplete) metamorphosis, and their development is described as hemimetabolous. Endopterygotes and a few exopterygotes have larvae whose form and habits, by and large, are very different from those of the adults. As a result, they undergo striking changes (complete metamorphosis), spread over two molts, in the formation of the adult (holometabolous development). The final juvenile instar has become specialized to facilitate these changes and is known as the pupa (see also Chapter 2, Section 3.3).

In insect evolution increasing functional separation has occurred between the larval phase, which is concerned with growth and accumulation of reserves, and the adult stage, whose functions are reproduction and dispersal. Associated with this trend is a tendency for an insect to spend a greater part of its life as a juvenile, which contrasts with the situation in many other animals. Thus, in apterygotes, the adult stage may be considerably longer than the juvenile stage. Furthermore, feeding (in the adult) serves to provide raw materials both for reproduction and for growth. In exopterygotes and primitive endopterygotes adults may live for a reasonable period, but this is not usually as long as the larval phase. Feeding in the adult stage is primarily associated with reproductive requirements, though in some insects it provides nutrients for an initial, short "somatic growth phase" in which the flight muscles, gut, and cuticle become fully developed. Many endopterygotes live for a relatively short time as adults and may feed little or not at all because sufficient reserves have been acquired during larval life to satisfy the needs of reproduction.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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