Morphology of male reproductive system in three species of Trypoxylon (Trypargilum) Richards (Hymenoptera: Crabronidae)

Abstract

-Variations in the adult male reproductive system among different groups of Hymenoptera offer characteristics that help studies on behavior and phylogenetics. The objective of this study was to describe the adult male reproductive system of three Trypoxylon (Trypargilum) species. For that, tissues were disseced, fi xed in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and postfi xed in 1% osmium tetroxide. The material was dehydratated and embedded for light and electron transmission microscopes. The species have similar reproductive systems, which are formed by a pair of testes, each one with three fusiforme follicles, from which emerges an efferent duct that later joins forming a deferent duct. The deferent duct opens into an ejaculatory duct. The fi rst half of the deferent duct is enlarged and differentiated in a region specialized in sperm storage, the seminal vesicle. The accessory gland fl ows in the post-vesicular region of the deferent duct. The testes and vesicles are both covered with a conjunctive capsule. Sexually mature individuals have all spermatogenesis stages in their follicles. Sperms are released from testes in bundles which are disorganized inside seminal vesicles.KEY WORDS: Histology, testes, spheciform wasp RESUMO -Variações no sistema reprodutor entre os diferentes grupos de Hymenoptera oferecem caracteres que auxiliam nos estudos de comportamento e fi logenia. O objetivo deste trabalho foi descrever o sistema reprodutor masculino de três espécies de Trypoxylon (Trypargilum). Para isso, os tecidos foram dissecados, fi xados em glutaraldeído 2,5% em tampão cacodilato de sódio 0,1 M, pH 7,2 e pós-fi xados em tetróxido de ósmio a 1%. O material foi desidratado e incluído para microscopias de luz e eletrônica de transmissão. As espécies possuem os sistemas reprodutores muito semelhantes, formados por um par de testículos, cada um com três folículos fusiformes, a partir dos quais emerge um ducto eferente que depois se juntam formando o ducto deferente. O ducto deferente termina no ducto ejaculatório. A primeira metade dos ductos deferentes é dilatada e diferenciada em uma região especializada no armazenamento de espermatozóides, a vesícula seminal. A glândula acessória desemboca na região pós-vesicular do ducto deferente. Testículos e vesículas seminais são envoltos por uma única cápsula conjuntiva. Indivíduos maduros sexualmente apresentam todos os estágios da espermatogênese em seus folículos. Os espermatozóides são liberados dos testículos em feixes, os quais estão desorganizados na vesícula seminal.

Morphology of male reproductive system of two solitary bee species (Hymenoptera: Apidae)

“…The epithelium found in the spermatic ducts along the reproductive tract of bees is similar to that described for social bees (Snodgrass 1956, Cruz-Landim & Cruz-Hofl ing 1969a, b, Dallacqua & Cruz-Landim 2003, Araújo et al 2005, Lima et al 2006, ants (Ball & Vison 1984, Wheeler & Krutzsch 1992, and wasps (Dirks & Sternburg 1972, Bushrow et al 2006, Moreira et al 2008. However, some differences are evident, such as the large amount of inclusions in the epithelium of the seminal vesicle and the differences in the epithelium type in the accessory glands found in the two bee species studied.…”

“…The ejaculatory duct is a single, median structure and presents a cuticle that shows its ectodermic origin, as in most insects (Bushrow et al 2006, Moreira et al 2008. The epithelium found in the spermatic ducts along the reproductive tract of bees is similar to that described for social bees (Snodgrass 1956, Cruz-Landim & Cruz-Hofl ing 1969a, b, Dallacqua & Cruz-Landim 2003, Araújo et al 2005, Lima et al 2006, ants (Ball & Vison 1984, Wheeler & Krutzsch 1992, and wasps (Dirks & Sternburg 1972, Bushrow et al 2006, Moreira et al 2008.…”

“…Other subfamilies of bees, such as Mellitinae and some Megachilinae, also present four follicles per testicle (Roig-Alsina & Michener 1993, Ferreira et al 2004 with the exception of Apis mellifera L. which has around 250. The occurrence of three follicles was reported in more basal bees such as Colletinae, Andreninae and Hactinae (Ferreira et al 2004, Araújo et al 2005, and wasps Crabronidae (Moreira et al 2008), considered a sister group to bees. On the other hand, this number varies from one to 11 in Formicidae (Wheeler & Krutzch 1992) and in wasps Chalcidoidea, where only one (Fiorillo et al 2008).…”

“…In these species, the spermatozoa leave the testicle in bundles and when they reach the seminal vesicles, these bundles become undone (Moreira et al 2004). Continuous sperm production is common in species that present long adult life and couple throughout this phase (Buschini 2007, Moreira et al 2008. Males of solitary bees, in general, emerge before the female and patrol the nidifi cation areas and search for newly emerged females (Raw 2002).…”

Morphology of testicular and post-testicular spermatozoa in Microstigmus arlei Richards, 1972 and M. nigrophthalmus Melo, 1992 (Hymenoptera: Apoidea: Pemphredoninae) with phylogenetic consideration

“…The general morphology has been maintained in the order, but the number of testicular follicles varies considerably among minor groups, without obvious phylogenetic indication: in the Aculeata, the occurrence of three testicular follicles, as in Microstigmus, was still reported in other sphecid wasps of the subgenus Trypoxylon (Trypargilum) ( Moreira et al, 2005a) as well as for some bee families (e.g. Andrenidae, Halictidae, some Megachilidae, Apidae sensu stricto Meliponini) ( Ferreira et al, 2004 andAraújo et al, 2005a) and in Vespidae ( Brito et al, 2005 andMoreira et al, 2005b).…”