Review The fat body of termites: Functions and stored materials Ana Maria Costa-Leonardo ⇑ , Lara Teixeira Laranjo, Vanelize Janei, Ives Haifig Laboratório de Cupins, Departamento de Biologia, Instituto de Biociências, Universidade Estadual Paulista – UNESP, Campus Rio Claro. Av. 24A, No. 1515, Bela Vista CEP: 13.506-900, Rio Claro, SP, Brazil article info Article history: Received 28 November 2012 Received in revised form 22 March 2013 Accepted 25 March 2013 Available online 3 April 2013 Keywords: Adipocytes Isoptera Storage proteins Termite queens Ultrastructure Urocytes abstract The functions of the fat body in the different castes of termites, and accumulation of energy reserves, pro- teins and urates within this organ, are reviewed. The termite fat body is involved in multiple metabolic activities, including recycling of nitrogen. Termite fat body showed three different types of cells: adipo- cytes, urocytes and mycetocytes, the latter restricted to the species Mastotermes darwiniensis. Adipocytes synthesize and store lipids, glycogen and several proteins. These cells also elaborate important peptides, including some that act in immune processes. Urocytes are responsible for the storage of spherocrystals of urates, which vary quantitatively among the termite castes. The different metabolic functions of the fat body in the several castes and stages of termites are associated with specific adipocyte morphologies. The synthesis and storage of different compounds modify the structure of the fat body; this differentiation is coordinated by hormones involved with molting and reproductive cycles. Ó 2013 Elsevier Ltd. All rights reserved. Contents 1. Introduction ......................................................................................................... 577 2. Structure and function ................................................................................................. 578 3. Fat body cells ........................................................................................................ 579 3.1. Adipocytes ..................................................................................................... 579 3.2. Urate cells ..................................................................................................... 579 3.3. Mycetocytes .................................................................................................... 579 4. Fat body in larvae and nymphs .......................................................................................... 580 5. Fat body in pseudergates and workers .................................................................................... 580 6. Fat body in presoldiers and soldiers ...................................................................................... 580 7. Fat body in imagos or alate reproductives ................................................................................. 581 8. Fat body in primary and neotenic reproductives ............................................................................ 582 9. Final considerations ................................................................................................... 585 Acknowledgements ................................................................................................... 586 References .......................................................................................................... 586 1. Introduction Colonies of termites have a different organization that of hyme- nopteran eusocial insects. The termites are diploids, sterile castes are present in both sexes, and they exhibit hemimetabolous devel- opment. The latter characteristic allows the engagement of young individuals in reproductive and colonial tasks and influences the caste systems of the different species of Isoptera (Noirot, 1989). Within a termite colony the reproductive pair, the king and the queen, derived from imagos, is solely responsible for reproduction. When the king or queen dies, replacement reproductives arise. These are often neotenic individuals whose reproductive apparatus matures before they reach the adult form. In addition to these indi- viduals, a termite colony also presents apterous castes, the workers and soldiers. The workers constitute the dominant caste and are responsible for most of the colony tasks, such as building, food col- 0022-1910/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jinsphys.2013.03.009 ⇑ Corresponding author. Tel.: +55 19 35264138; fax: +55 19 35340009. E-mail address: amcl@rc.unesp.br (A.M. Costa-Leonardo). Journal of Insect Physiology 59 (2013) 577–587 Contents lists available at SciVerse ScienceDirect Journal of Insect Physiology journal homepage: www.elsevier.com/locate/jinsphys