RESUMO

The sperm morphology can provide helpful information about sexual selection, phylogeny, and the evolutionary history of a given animal group. However, there is limited or no knowledge of many taxa, especially those belonging to insects, a vast and highly diverse group. An example is the Miridae, or plant bugs, which belong to the infraorder Cimicomorpha (Heteroptera), where only three out of 17 families have published data on their sperm morphology. Here we described the Miridae sperm structure by analyzing Pycnoderes incurvus sperm under light and transmission electron microscopy. In this species, the spermatozoa were as long and slender as those of most insects. However, the anterior-most region was twisted, a characteristic first reported for Heteroptera. The acrosome was coated with electron-dense material, most likely extra-acrosomal. The centriole adjunct was a notably long, cylindrical and compact structure connecting the nucleus to the flagellar elements, with just clove-like electron-lucent points in cross-section, also features unique to Miridae so far. The flagella exhibited an axoneme of 9 + 9 + 2 microtubules and two symmetrical mitochondrial derivatives. The latter two partially embrace the axoneme, and each exhibits two paracrystalline areas and a bridge connecting it to the axoneme; these are considered Heteroptera synapomorphies that support their monophyly. RESEARCH HIGHLIGHTS: The P. incurvus sperm showed a twisted acrosome, the first reported for Heteroptera. The centriolar adjunct is a sole structure linking the nucleus and flagellum. The flagella presented the synapomorphies supporting Heteroptera monophyly.

RESUMO

The Hemimetabola Collection of the Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, located in Berlin, Germany, holds types of 22 species of Triatominae (Hemiptera: Heteroptera: Reduviidae) belonging to six genera: Belminus Stål, 1859; Eratyrus Stål, 1859; Meccus Stål, 1859; Panstrongylus Berg, 1879; Rhodnius Stål, 1859; and Triatoma Laporte, 1832. We present a detailed list containing nomenclatural, taxonomic and label data, and photographs of specimens and their labels.

Assuntos

RESUMO

The bronze bug, Thaumastocoris peregrinus Carpintero & Dellapé (Heteroptera: Thaumastocoridae), is an exotic emerging pest in Eucalyptus commercial forests in South America, Africa, and southern Europe. Information on the chemical communication system and reproductive ecology of this insect is scant, and it may be relevant for designing management strategies for eucalypt plantations. Males emit large amounts of 3-methyl-2-butenyl butyrate, which attracts conspecific adult males but not females. To learn more about the biological function of this putative male-produced pheromone, we quantified this compound in volatile emissions collected from males, females, and couples, in three 4-h collecting periods during the morning, afternoon, and night of a single 24-h cycle. Our results showed that virgin males emit 3-methyl-2-butenyl butyrate in a diel time pattern, with an almost sevenfold difference between the afternoon emission peak compared to morning or night hours. In addition, we show that in the presence of females, males emit the compound in the same amounts throughout the photocycle. While a definite function cannot yet be attributed to the emission of 3-methyl-2-butenyl butyrate by T. peregrinus males, our findings point to an intraspecific function, possibly one related to male-male competition.

Assuntos

RESUMO

The sperm morphology of two predatory bugs Amphiareus constrictus and Blaptostethus pallescens, representing the tribes Dufouriellini and Blasptostethini, respectively, was described using light and transmission electron microscopy. The spermatozoa of Amphiareus constrictus and Blaptostethus pallescens are fine and long, each measuring 216.6µm and 181.0µm in length, of which 37.0µm and 11.6µm, respectively, comprise the nuclei. When stained with DAPI (for DNA), the posterior half of the nucleus in B. pallescens exhibited low fluorescence, while in A. constrictus this feature was observed only in the last 6µm. In both species, as in Heteroptera in general, the spermatozoa have, in the head region, an acrosome and nucleus, and in the flagellar region, an axoneme with 9 accessory tubules, 9 peripheral doublets and 2 central microtubules (9+9+2 microtubules), 2 mitochondrial derivatives (MDs), and a centriolar adjunct in the nucleus-flagellum transition. However, unlike most Heteroptera, in these species, the MDs are asymmetric, and the centriolar adjunct is quite long and encompasses completely the posterior nuclear end and the anterior tips of the MDs. These features are considered as derived, thus supporting the condition derived of Anthocoridae within Cimicomorpha. In addition, several traits of the spermatozoa of these two species easily distinguish one species (and probably a tribe) from the other; for example, the difference of formats in the MDs, and the long anterior projection of the centriolar adjunct parallel to the nucleus in B. pallescens.

Assuntos

RESUMO

Next-generation sequencing data analysis on Triatoma infestans Klug, 1834 (Heteroptera, Cimicomorpha, Reduviidae) revealed the presence of the ancestral insect (TTAGG)n telomeric motif in its genome. Fluorescence in situ hybridization confirms that chromosomes bear this telomeric sequence in their chromosomal ends. Furthermore, motif amount estimation was about 0.03% of the total genome, so that the average telomere length in each chromosomal end is almost 18 kb long. We also detected the presence of (TTAGG)n telomeric repeat in mitotic and meiotic chromosomes in other three species of Triatominae: Triatoma dimidiata Latreille, 1811, Dipetalogaster maxima Uhler, 1894, and Rhodnius prolixus Ståhl, 1859. This is the first report of the (TTAGG)n telomeric repeat in the infraorder Cimicomorpha, contradicting the currently accepted hypothesis that evolutionarily recent heteropterans lack this ancestral insect telomeric sequence.

RESUMO

Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted meiosis for sex chromosomes and high variation in chromosome number. The family Reduviidae, which belongs to this infraorder, is also recognized by high variability of heterochromatic bands and chromosome location of 18S rDNA loci. We studied here five species of Reduviidae (Harpactorinae) with predator habit, which are especially interesting because individuals are found solitary and dispersed in nature. These species showed striking variation in chromosome number (including sex chromosome systems), inter-chromosomal asymmetry, different number and chromosome location of 18S rDNA loci, dissimilar location and quantity of autosomal C-heterochromatin, and different types of repetitive DNA by fluorochrome banding, probably associated with occurrence of different chromosome rearrangements. Terminal chromosome location of C-heterochromatin seems to reinforce the model of equilocal dispersion of repetitive DNA families based in the "bouquet configuration".