First Record of Zaprionus tuberculatus Malloch, 1932 (Diptera: Drosophilidae) in Minas Gerais, Brazil

ABSTRACT The Afrotropical Zaprionus Coquillett, 1902 (Diptera: Drosophilidae) has gained visibility since the 1990s due to the geographic expansion of Zaprionus indianus Gupta, 1970. More recently, a second species, Zaprionus tuberculatus Malloch, 1932, invaded regions outside its original African regions, causing economic concerns, particularly in Europe. In 2021, Z. tuberculatus was captured for the first time in the Americas, specifically in urban parks, and preserved fragments of the Brazilian Cerrado, causing concerns about the competition with native drosophilids. Here we report the occurrence of Z. tuberculatus 900 km from its first record in urban and rural areas of Viçosa, MG, but not in forest fragments. Considering the great capacity for dispersion and the potential of Z. tuberculatus to compete with native drosophilids species, as well as the potential harm to fruit production when co-occurring with Drosophila suzukii (Matsumura, 1931), further studies would be necessary to monitor this invasion and create mechanisms to control it.

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

Bees can form all levels of social organization, from solitary to advanced eusocial societies. Although 80 percent of the species exist as solitary species, most researches emphasize social species. This study focuses on the description of the male reproductive system of the solitary beesThygater analis (Lepeletier) and Melitoma segmentaria (Fabricius) and searches for traits that support behavioral and phylogenetic studies. The reproductive system of males were dissected, fixed in 2.5 percent glutaraldehyde in 0.1 M sodium cacodylate buffer pH 7.2 and post-fixed with 1 percent osmium tetroxide. The tissue was dissected and included for light microscopy. The species presented similar anatomical traits, including paired testicles, seminal vesicles, deferent ducts, accessory glands and an ejaculatory duct. Each testicle was composed of four follicles. In both species, a testicle and a seminal vesicle were surrounded by a joint capsule, forming a seminal vesicle-testicle complex. The two species presented accessory glands with very distinct morphological traits. The anatomic pattern and the histological traits of the reproductive system of the species studied were similar to those described for other bees. In addition, these traits can be used to differentiate species and allow inferences concerning their reproductive biology.

Morphology of male reproductive system in three species of Trypoxylon (Trypargilum) Richards (Hymenoptera: Crabronidae) / Morfologia do sistema reprodutor masculino em três espécies de Trypoxylon (Trypargilum) Richards (Hymenoptera: Crabronidae)

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, fixed in 2.5 percent glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2 and postfixed in 1 percent 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 first half of the deferent duct is enlarged and differentiated in a region specialized in sperm storage, the seminal vesicle. The accessory gland flows 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.

Variações no sistema reprodutor entre os diferentes grupos de Hymenoptera oferecem caracteres que auxiliam nos estudos de comportamento e filogenia. O objetivo deste trabalho foi descrever o sistema reprodutor masculino de três espécies de Trypoxylon (Trypargilum). Para isso, os tecidos foram dissecados, fixados em glutaraldeído 2,5 por cento em tampão cacodilato de sódio 0,1 M, pH 7,2 e pós-fixados em tetróxido de ósmio a 1 por cento. 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.

Ultrastructural, histological and histochemical characteristics of the epithelial wall of the seminal vesicle of mature Scaptotrigona xanthotricha moure males (Hymenoptera, apidae, meliponini)

The seminal vesicles of mature Scaptotrigona xanthotricha males were investigated using light microscopy, histochemistry and transmission electron microscopy. The globular seminal vesicles were ~450 ìm in diameter and consisted of a sperm-filled lumen and a single layer of epithelium surrounded externally by a muscular sheath. The mitochondria-rich epithelial cells had many inclusions in the basal region. These inclusions were relatively large and contained membranous structures similar to myelin figures. The epithelial cells of the seminal vesicle showed none of the features characteristically associated with a secretory function, which suggested that the material in which the spermatozoa were immersed in the vesicle lumen was produced elsewhere along the ducts and/or during sexual maturation of the males. Spermatozoa were occasionally seen inside the inclusions, which suggested a possible spermiophagic activity for this epithelium.

Morphology and ultrastructure of the spermatozoa of Scaptotrigona xanthotricha moure (Hymenoptera, Apidae, Meliponini)

The spermatozoa of Scaptotrigona xanthotricha, a stingless bee under extinction in some Brazilian states, are described. Seminal vesicles of adult males were dissected and processed for light and transmission electron microscopy. The spermatozoa were long (about 90 µm) and slender. The head consisted of an acrosome formed by an acrosomal vesicle covering the perforatorium and the nucleus. The latter was homogeneous, compact and about 11 µm long. The flagellum consisted of an axoneme, with the typical 9+9+2 microtubule arrangement that began just below the nuclear base. The two mitochondrial derivatives were asymmetric in length and diameter, and had two accessory bodies. The nucleus was attached to the flagellum by a centriolar adjunct. These results indicate that the spermatozoa of S. xanthotricha are similar to those of other Meliponini but differ markedly from other insect groups. The ultrastructure of hymenopteran spermatozoa may be a useful character for phylogenetic studies.

Release, behavior and phylogenetic significance of spermatozoa in bundles in the seminal vesicle during sexual maturation in Aculeata (Hymenoptera)

In this report, we describe how spermatozoa are released in the Aculeata Melipona quadrifasciata (Apidae) and Acromyrmex subterraneus (Formicidae). Immature and sexually mature adult males of both species were dissected and their seminal vesicles, vas deferens and testes were processed for light and transmission electron microscopy. At the end of spermatogenesis, the spermatozoa still formed bundles, with the anterior end of their heads inserted into electron dense material. These bundles migrates to the seminal vesicles and, as the adults matured sexuality, the bundles started to disorganize and the spermatozoa became separeted. At the end sexual maturation, the seminal vesicles contained no bundles, but were completely full of free spermatozoa. In the Symphyta, as in the Aculeata studied here, the spermatozoa leave the testis in bundles. But there is no dissociation of spermatozoa from the bundles during sexual maturation. The Aculeata have been suggested to be derived from parasitic wasps that, in turn, derived from the Symphyta. Hence, the release of spermatozoa in bundles in the Aculeata is reverse characteristic or may indicate that this group is derived directly from the Symphyta.

Occurrence of polygyny in Acromyrmex subterraneus molestans Santschi 1925 (Hymenoptera: Formicidae)

O termo poliginia se refere à coexistência de duas ou mais rainhas férteis na colônia. Coletou-se no campus da Universidade Federal de Viçosa uma colônia de Acromyrmex subterraneus molestans Santschi contendo 14 rainhas, com o objetivo de verificar se todas elas eram ovipositoras e férteis. O volume do jardim de fungo no ninho era de 500 ml com grande número de larvas e pupas. Observações do desenvolvimento dos ovários e espermatecas indicaram que 13 rainhas tinham copulado e seus ovários não mostraram diferenças morfológicas. Isto indicaria que a poliginia não é acidental e pode representar uma estratégia adaptativa para otimizar o desenvolvimento inicial de colônias em A. subterraneus molestans.

Preparation of sand fly (Diptera: Psychodidae: Phlebotominae) specimens for histological studies

Phlebotominae sand fly specimens were prepared for histological and physiological studies. Different fixatives were tested on sectioned and whole bodied adult females in order to obtain good fixation and provide satisfactory penetration of the embedding media. All fixed specimens were infiltrated (up to seven days under 5ºC) and embedded in hydroxyethyl metacrylate. Two-three æm sections were stained, mounted in Canada balsam and observed by light microscopy. Best results were achieved when whole bodied insects were double fixed in Bouin's and Carnoy's fluids (4 h/2 h) and stained in Hematoxilin/Eosin or fixed in calcium formaldehyde and stained in mercury bromophenol blue