RESUMO
Termites are eusocial cockroaches, which have received great attention due to their diversity of reproductive strategies. Although these novelties allow new interpretations concerning the mating biology of these insects, studies highlighting the structure of the reproductive system are limited to some termite lineages. Here we provide the first comparative analysis of the reproductive system of a drywood termite, using different aged males of Cryptotermes brevis as models. This species represents an important structural pest in tropical regions, and most aspects of its reproductive biology remain unknown, especially on males. The reproductive apparatus of C. brevis is equipped with paired testes, composed of seven testicular lobes, in which developing spermatozoa are located. The basal portion of the lobes connects to the vasa deferentia and transport spermatozoa to a pair of enlarged chambers, the seminal vesicles. These structures join in a median ejaculatory duct, which opens to the external region through a retractile penis. Spermatozoa were observed in all C. brevis males, exhibiting elongated morphology and measuring about 10 µm in length/4 µm in width. Compared with last-instar nymphs and alates, functional kings showed enlarged testes and seminal vesicles, as well as an intense secretory activity towards the lumen of the latter structures. Histochemical tests evidenced strongly PAS and xylidine Ponceau positive reactions of the secretion only in functional kings, indicating the occurrence of glycoproteins. Thus, we suggest that morphophysiological changes establish during the maturation of the reproductive system in C. brevis.
Assuntos
Envelhecimento/fisiologia , Genitália/anatomia & histologia , Genitália/crescimento & desenvolvimento , Isópteros/anatomia & histologia , Isópteros/crescimento & desenvolvimento , Animais , Genitália/citologia , Genitália/ultraestrutura , MasculinoRESUMO
The functions of the fat body in the different castes of termites, and accumulation of energy reserves, proteins 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: adipocytes, 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.
Assuntos
Corpo Adiposo/metabolismo , Proteínas de Insetos/metabolismo , Isópteros/metabolismo , Animais , Corpo Adiposo/citologia , Glicogênio/metabolismo , Isópteros/citologia , Isópteros/crescimento & desenvolvimento , Metabolismo dos LipídeosRESUMO
The subfamily Syntermitinae comprises 14 genera of termites that are exclusively neotropical. The present study reports morphological data about mandibulate nasute soldiers from termite species belonging to three different genera within this subfamily. We describe tergal glands that were present under all tergites of soldiers of the following species: Cornitermes cumulans, Procornitermes araujoi, Syntermes nanus, and Syntermes wheeleri. The tergal glands were composed of class 2 and class 3 cells. Class 2 cells never reached the cuticle and were located below a flat layer of epidermal cells. Class 3 cells, composed of secretory cells and canal cells, were sporadic, whereas class 2 secretory cells were abundant. Secretory cells of class 3 were narrow and their cytoplasms were filled with several clear, oval-shaped vesicles with limiting membranes. The ultrastructure of class 2 cells showed well-developed smooth endoplasmic reticulum, Golgi apparatus, elongated mitochondria, several electron-lucent vesicles, and electron-dense granules that contain paracrystalline structures in S. nanus. Scanning electron micrographs displayed pores, campaniform sensilla and hairs in the outer cuticle of the soldier tergites. We hypothesize that soldier tergal glands may be involved in the production of defensive compounds, which occur in similar glands of certain cockroaches, or of primer pheromones, that might act in the regulation of soldier differentiation in the termite colony. To date, tergal glands have only been described in termite imagoes, and their occurrence in these soldiers of basal Syntermitinae implies a specific role in this caste that is still speculative and needs to be clarified.