The Insects: An Outline of Entomology
P. J. Gullan
Format: PDF / Kindle (mobi) / ePub
Insects represent over half of the planet’s biological diversity. This popular textbook provides a comprehensive introduction to this extraordinary diversity, and places entomology central to the theory and practice of evolutionary and ecological studies.
Fully revised, this fifth edition opens with a chapter concerning the popular side of insect studies, including insects in citizen science, zoos and butterfly houses, and insects as food for humans and animals. Key features of insect
structure, function, behaviour, ecology and classification are integrated with appropriate molecular studies. Much of the book is organized around major biological themes: living on the ground, in water, on plants, in colonies, and as predators, parasites/parasitoids and prey insects. A strong evolutionary theme is maintained throughout.
There is major revision to the chapter on systematics and a new chapter, Insects in a Changing World, includes insect responses to, and the consequences of, both climate change and human-assisted global alterations to distributions. Updated ‘Taxoboxes’ demonstrate topical issues and provide concise information on all aspects of each of the 28 major groupings (orders) of insects, plus the three orders of non-insect hexapods. New boxes describe a worrying increase in insect threats to landscape and commercial trees (including eucalypts, palms and coffee) and explain the value of genetic data, including evolutionary developmental biology and DNA barcoding, in insect biodiversity studies.
The authors maintain the clarity and conciseness of earlier editions, and extend the profuse illustrations with new hand-drawn figures. Over 50 colour photographs, together with the informative text and an accompanying website with links to video clips, appendices, textboxes and further reading lists, encourage a deeper scientific study of insects. The book is intended as the principal text for students studying entomology, as well as a reference text for undergraduate and graduate courses in the fields of ecology, agriculture, fisheries and forestry, palaeontology, zoology, and medical and veterinary science.
overwhelming importance and will be discussed more fully in this context in section 6.3. Here we provide a general picture of the endocrine centers and the hormones that they export. Historically, the implication of hormones in the processes of molting and metamorphosis resulted from simple but elegant experiments. These utilized techniques that removed the influence of the brain (decapitation), isolated the hemolymph of different parts of the body (ligation), or artificially connected the
when they were reared in 21% oxygen (as in normal air) ( ) (after Loudon 1989). Each point on the graph is for a single larva and is the average of the summed areas of the dorsal, ventral, and visceral tracheae for six pairs of abdominal spiracles. This hypertrophy appears to be inconsistent with the widely accepted hypothesis that tracheae contribute an insignificant resistance to net oxygen movement in insect tracheal systems. Alternatively, hypertrophy may simply increase the amount of air
cibarial pump are indicated but not fully labeled. Contraction of the respective dilator muscles causes dilation of the pharynx or cibarium and fluid is drawn into the pump chamber. Relaxation of these muscles results in elastic return of the pharynx or cibarial walls and expels food upwards into the oesophagus. (After Snodgrass 1935.) structurally similar, being columnar with microvilli (finger-like protrusions) covering the inner surface. The distinction between the almost indiscernible
producers. However, obvious anomalies arise when identical or very similar pheromones are synthesized from chemicals derived from identical diets by unrelated insects. Even if individual components are shared by many species, the mixture of pheromones is very often species-specific. It is evident that pheromones, and the stereotyped behaviors that they evoke, are highly significant in maintenance of reproductive isolation between species. The species-specificity of sex pheromones avoids
the burden of ever-increasing deleterious effects on adjacent vital functions, or an upper limit on the volume of new cuticle that can develop sub-epidermally in the pharate pupa within the final-instar larva, under juvenile hormonal control. Size alone may be important in female choice: in some stick-insects (also called walking sticks) larger males often monopolize females. Males fight over their females by boxing at each other with their legs while grasping the female’s abdomen with their