Sex Determination In Hymenoptera Research Articles

Bracon brevicornis Genome Showcases the Potential of Linked-Read Sequencing in Identifying a Putative Complementary Sex Determiner Gene.

Bracon brevicornis is an ectoparasitoid of a wide range of larval-stage Lepidopterans, including several pests of important crops, such as the corn borer, Ostrinia nubilalis. It is also one of the earliest documented cases of complementary sex determination in Hymenoptera. Here, we present the linked-read-based genome of B. brevicornis, complete with an ab initio-derived annotation and protein comparisons with fellow braconids, Fopius arisanus and Diachasma alloeum. We demonstrate the potential of linked-read assemblies in exploring regions of heterozygosity and search for structural and homology-derived evidence of the complementary sex determiner gene (csd).

Gene copy number and differential gene expression in haploid and diploid males of the stingless bee, Melipona quadrifasciata

Complementary sex determination in Hymenoptera implies that heterozygosity at the sex locus leads to the development of diploid females, whereas hemizygosity results in haploid males. Diploid males can arise through inbreeding. In social species, these pose a double burden on colony fitness, from significant reduction in its worker force and through being less viable and fertile than haploid males. Apart from being “misfits”, diploid males are of interest to assess molecular correlates for possibly ploidy-related bionomic differences. Herein, we generated suppression subtractive cDNA libraries from newly emerged haploid and diploid males of the stingless bee Melipona quadrifasciata to enrich for differentially expressed genes. Gene Ontology classification revealed that in haploid males more DEGs were related to stress responsiveness, biosynthetic processes, reproductive processes and spermatogenesis, whereas in diploid ones differentially expressed genes were associated with cellular organization, nervous system development and amino acid transport were prevalent. Furthermore, both libraries contained over 40 % ESTs representing possibly novel transcripts. Quantitative RT-PCR analyses confirmed the differential expression of a representative DEG set in newly emerged males. Several muscle formation and energy metabolism-related genes were under-expressed in diploid males. On including 5-day-old males in the analysis, changes in transcript abundance during sexual maturation were revealed.

A synthesis of gynandromorphy among wild bees (Hymenoptera: Apoidea), with an annotated description of several new cases

We here describe six new specimens of gynanders (i.e. specimens where male and female phenotypic characters occur on the same individual) from distinct families of wild bees (Hymenoptera, Apoidea). The newly described cases include Melitta haemorrhoidalis (Fabricius 1775) (Melittidae), Dasypoda hirtipes (Fabricius 1775) (Melittidae), Anthophora plumipes (Pallas 1772) (Apidae), Bombus monticola rondoui Vogt 1909 (Apidae), Bombus vestalis vestalis (Fourcroy 1785) (Apidae) and Bombus vestalis sorgonis (Strand 1917) (Apidae). Descriptions are accompanied by behavioural observations of gynanders under natural conditions before their capture for two cases. We also list 109 gynanders already described in bees and we interpret the newly described cases along these previous records. The putative origins of gynandromorphy are then discussed in the light of recent advances in the field of sex determination in Hymenoptera.

Male parentage and queen mating frequency in the bumblebee Bombus ignitus (Hymenoptera: bombinae)

AbstractKin selection theory predicts conflict between queens and workers in the social insect colony with respect to male production. This conflict arises from the haplodiploid system of sex determination in Hymenoptera that creates relatedness asymmetries in which workers are more closely related to the sons of other workers than to those of the queen. In annual hymenopteran societies that are headed by a single queen, the mating frequency of the queen is the only factor that affects the colony kin structure. Therefore, we examined the mating structure of queens and the parentage of males in a monogynous bumblebee, Bombus ignitus, using DNA microsatellites. In the seven colonies that were studied, B. ignitus queens mated once, thereby leading to the prediction of conflict between the queen and workers regarding male production. In each of the five queen‐right colonies, the majority of the males (95%) were produced by the colony's queen. In contrast, workers produced approximately 47% of all the males in two queenless colonies. These results suggest that male production in B. ignitus is a conflict between queen and workers.

Mother's boy or daddy's girl? Sex determination in Hymenoptera

Mother's boy or daddy's girl? Sex determination in Hymenoptera

Sex determination in honey bees (Apinae and Meliponinae) and its consequences

The first experiments on sex determination in bees began with Dzierzon, Meves, Nachtsheim, Paulcke, Petrunkewitsch, Manning. Whiting, (1943) found multiple alleles in Bracon xo that are the Rosetta stone of sex determination in Hymenoptera. Whiting also discovered that some species of microhymenoptera do not possess xo sex alleles. Therefore, Hymenoptera apparently presents two types of sex determination superimposed on haplodiploidy. In the panmictic groups hemizygous (xo1, xo2,... xon) and homozygous (xo1xo1, xo2xo2... xonxon) are males while heterozygous (xo1xo2, ... xon-1xon) are females. There is no such series of xon in endogamous Hymenoptera, since the constant elimination of diploid males would be damaging to the population and the mutation of xo to xon would be quickly eliminated. Besides the Whiting hypothesis, four others are discussed. The new hypothesis of genomic imprinting, of Beukeboom, is eliminated since: a) spermatozoa that develop within the egg produce male tissue; b) telitokous parthenogenesis due to the fusion of two haploid cells develop into females; c) last instar larvae treated with juvenile hormone become queens. The Cunha and Kerr hypothesis (female determining genes are totally or partially additive and male determination is totally or partially nonadditive) explains all known cases. The xo is a female determining gene. Sex determination in social bees led to the gradual evolution of two systems of caste determination: one in which queens and workers are similar and males are very different (Apinae), and another in which workers and males are very similar and both very different from the queens (Meliponinae). This second system in stingless bees implies that many of the mutations that improve worker capacities also affect the males that will carry out some activities that in Apis are clearly female ones. Ten of these activities are described.

Sex determination in Hymenoptera: a need for genetic and molecular studies.

Sex-determining mechanisms appear to be very diverse in invertebrates. Haplodiploidy is a widespread mode of reproduction in insects: males are haploid and females are diploid. Several models have been proposed for the genetic mechanisms of sex determination in haplodiploid Hymenoptera. Although a one-locus multi-allele model is valid for several species, sex determination in other species cannot be explained by any of the existing models. Evidence for and predictions of two recently proposed models are discussed. Some genetic and molecular approaches are proposed to study sex determination in Hymenoptera.

Increased tissue concentrations of histamine in the duodenal mucosa of children with coeliac disease.

Tissue concentrations of histamine have been estimated in peroral duodenal biopsy specimens from five children with coeliac disease while on a gluten-free diet and after a three-month gluten challenge. Histamine concentrations in the patients on a diet did not differ significantly from a group of control children. However after gluten challenge, histological relapse of the duodenal mucosa in each patient was associated with increased tissue concentrations of histamine. The findings suggest that histamine may be involved in the pathogenesis of the small intestinal mucosal changes in children with coeliac disease.

Local Mate Competition and Parental Investment in Social Insects

Efforts to develop formulas for contrasting genetic interests of workers and queens in social Hymenoptera are complicated by many factors, including multiple matings by queens, oviposition by unmated females, and mating rivalry among genetic relatives (Hamilton's "local mate competition"). Because of haplodiploid sex determination in Hymenoptera, when such influences are absent, queens benefit from 1:1 sex ratios of investment (male: female) in reproductive offspring, workers from 1:3 ratios among reproductive siblings. Reports of variable ratios, including many well above 1:3, and female biases in nonsocial Hymenoptera and diplodiploid termites, implicate local mate competition and raises questions about previous interpretations that workers have their way.

Chromosome Numbers of the Red and the Black Imported Fire Ants, Solenopsis invicta1 and S. richteri1, 3

The chromosome number for the red and black imported fire ants, Solenopsis invicta Buren and S. richteri Forel, was determined to be n = 16. A special case of diploidy in S. invicta males has been observed; these diploid males are sterile. The occurrence of diploid males as well as normal haploid males in S. invicta is explicable under the hypothesis that sex determination in Hymenoptera is governed by genotypes at one or more sex loci.

Oögenesis, fertilization and early cleavage in Habrobracon

AbstractSince differential maturation has been used in explaining sex determination in Hymenoptera, the pertinent stages were studied cytologically in Habrobracon by using whole mounts of timed eggs stained by the Feulgen reaction.The egg is laid with the maturation figure in an arrested first anaphase close to the ventral egg surface, and with the spindle horizontal to the latter. Eggs from different stocks show differences in position of maturation figure. A single sperm enters during oviposition, the maturation spindle revolves to a vertical position and normal maturation and change of the sperm ensues. Nuclei of unfertilized eggs behave similarly. Ten chromosomes enter each of the three polar and the one matured egg nuclei, the latter being always the innermost of the four. Unfertilized eggs have ten chromosomes at first and eleventh cleavages; fertilized eggs have around the expected twenty. Chromosomes in maturation divisions are too small and round to show individual differences. There is no good evidence of chromosome elimination.

Selective Fertilization and Sex-Determination in Hymenoptera

Selective Fertilization and Sex-Determination in Hymenoptera

Selective Fertilization and Sex-Determination in Hymenoptera

Selective Fertilization and Sex-Determination in Hymenoptera

Temperature and Other Factors Concerned in Male Biparentalism in Habrobracon

IN the parasitic wasp, H1abrobracon juglandis (Ashmead) crosses of orange-eyed (recessive) females by wild type (black) males produce, according to sex-linkoid inheritance, black heterozygous females from fertilized eggs and orange azygous males from unfertilized eggs. In 1921 (Whiting, P. W., '21) black biparental males were also reported. These anomalous males were called patroclinous because they showed the dominant paternal trait. They were supposed to be haploid mosaics with part of the body derived from the sperm nucleus alone (androgenesis). A few proved such by breeding test, but later genetic evidence indicated that the majority at least are diploid (Whiting, P. MT., and Anna R. Whiting, '25). The genetic and chromosomal constitution of these males is of interest, bearing as it does on the problem of sexdetermination in Hymenoptera. The ratios in which biparental males, females and haploid males occur has likewise excited interest. The two phases of the problem of male biparentalism, ratios and composition, have appeared somewhat separate, but doubtless each has an important relation to the other. As a result of accumulation of several groups of data bearing especially on variation in ratios, it has been planned in the present paper to report such as seem likely to aid in solving the problem. The material is reported here for the first time except for that of Anna