Book contents
- Frontmatter
- Contents
- Preface
- Acknowledgments
- PART I The Head, Ingestion, Utilization and Distribution of Food
- 1 Head
- 2 Mouthparts and feeding
- 3 Alimentary canal, digestion and absorption
- 4 Nutrition
- 5 Circulatory system, blood and immune systems
- 6 Fat body
- PART II The Thorax and Locomotion
- PART III The Abdomen, Reproduction and Development
- PART IV The Integument, Gas Exchange and Homeostasis
- PART V Communication
- Taxonomic index
- Subject index
2 - Mouthparts and feeding
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Acknowledgments
- PART I The Head, Ingestion, Utilization and Distribution of Food
- 1 Head
- 2 Mouthparts and feeding
- 3 Alimentary canal, digestion and absorption
- 4 Nutrition
- 5 Circulatory system, blood and immune systems
- 6 Fat body
- PART II The Thorax and Locomotion
- PART III The Abdomen, Reproduction and Development
- PART IV The Integument, Gas Exchange and Homeostasis
- PART V Communication
- Taxonomic index
- Subject index
Summary
The mouthparts are the organs concerned with feeding, comprising the unpaired labrum in front, a median hypopharynx behind the mouth, a pair of mandibles and maxillae laterally, and a labium forming the lower lip. In Collembola, Diplura and Protura the mouthparts lie in a cavity of the head produced by the genae, which extend ventrally as oral folds and meet in the ventral midline below the mouthparts (Fig. 2.1). This is the entognathous condition. In the Insecta the mouthparts are not enclosed in this way, but are external to the head, the ectognathous condition.
ECTOGNATHOUS MOUTHPARTS
The form of the mouthparts is related to diet, but two basic types can be recognized: one adapted for biting and chewing solid food, and the other adapted for sucking up fluids.
Biting mouthparts
Labrum The labrum is a broad lobe suspended from the clypeus in front of the mouth and forming the upper lip (Figs. 1.2, 2.2a). On its inner side it is membranous and may be produced into a median lobe, the epipharynx, bearing some sensilla. The labrum is raised away from the mandibles by two muscles arising in the head and inserted medially into the anterior margin of the labrum. It is closed against the mandibles in part by two muscles arising in the head and inserted on the posterior lateral margins on two small sclerites, the tormae, and, at least in some insects, by a resilin spring in the cuticle at the junction of the labrum with the clypeus.
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- Information
- The InsectsStructure and Function, pp. 12 - 37Publisher: Cambridge University PressPrint publication year: 1998
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