scholarly journals Identification of a queen pheromone mediating the rearing of adult sexuals in the pharaoh ant Monomorium pharaonis

2020 ◽  
Vol 16 (8) ◽  
pp. 20200348
Author(s):  
Ricardo Caliari Oliveira ◽  
Jonas Warson ◽  
David Sillam-Dussès ◽  
Beatriz Herrera-Malaver ◽  
Kevin Verstrepen ◽  
...  
Keyword(s):  
Social Insect ◽  
Division Of Labour ◽  
Queen Pheromone ◽  
Egg Laying ◽  
Fire Ants ◽  
Dual Function ◽  
Monomorium Pharaonis ◽  
Queen Pheromones ◽  
Fertility Status ◽  
First Time

The division of labour between reproductive queens and mostly sterile workers is among the defining characteristics of social insects. Queen-produced chemical signals advertising her presence and fertility status, i.e. queen pheromones, are normally used to assert the queen's reproductive dominance in the colony. Most queen pheromones identified to date are chemicals that stop the daughter workers from reproducing. Nevertheless, it has long been suggested that queen pheromones could also regulate reproduction in different ways. In some multiple-queen ants with obligately sterile workers, for example—such as fire ants and pharaoh ants—queen pheromones are thought to regulate reproduction by inhibiting the rearing of new sexuals. Here, we identify the first such queen pheromone in the pharaoh ant Monomorium pharaonis and demonstrate its mode of action via bioassays with the pure biosynthesized compound. In particular, we show that the monocyclic diterpene neocembrene, which in different Monomorium species is produced solely by fertile, egg-laying queens, strongly inhibits the rearing of new sexuals (queens and males) and also exerts a weakly attractive ‘queen retinue’ effect on the workers. This is the first time that a queen pheromone with such a dual function has been identified in a social insect species with obligately sterile workers.

scholarly journals A conserved class of queen pheromones? Re-evaluating the evidence in bumblebees ( Bombus impatiens )

2015 ◽  
Vol 282 (1817) ◽  
pp. 20151800 ◽  
Author(s):  
Etya Amsalem ◽  
Margarita Orlova ◽  
Christina M. Grozinger
Keyword(s):  
Bombus Terrestris ◽  
Division Of Labour ◽  
Queen Pheromone ◽  
Worker Reproduction ◽  
Egg Laying ◽  
Bombus Impatiens ◽  
Queen Pheromones ◽  
Reproductive Division Of Labour ◽  
Reproductive Division ◽  
Adult Exposure

The regulation of reproductive division of labour is a key component in the evolution of social insects. Chemical signals are important mechanisms to regulate worker reproduction, either as queen-produced pheromones that coercively inhibit worker reproduction or as queen signals that honestly advertise her fecundity. A recent study suggested that a conserved class of hydrocarbons serve as queen pheromones across three independent origins of eusociality. In bumblebees ( Bombus terrestris ), pentacosane ( C 25) was suggested to serve as a queen pheromone. Here, we repeat these studies using a different species of bumblebee ( Bombus impatiens ) with a more controlled experimental design. Instead of dequeened colonies, we used same-aged, three-worker queenless groups comprising either experienced or naive workers (with/without adult exposure to queen pheromone). We quantified three hydrocarbons ( C 23, C 25 and C 27) on the cuticular surfaces of females and tested their effects on the two worker types. Our results indicate differences in responses of naive and experienced workers, genetic effects on worker reproduction, and general effects of hydrocarbons and duration of egg laying on ovary resorption rates. However, we found no evidence to support the theory that a conserved class of hydrocarbons serve as queen pheromones or queen signals in Bombus impatiens .

scholarly journals Conserved queen pheromones in bumblebees: A reply to Amsalem et al.

2016 ◽  
Author(s):  
Luke Holman ◽  
Jelle S van Zweden ◽  
Ricardo Caliari Oliveira ◽  
Annette van Oystaeyen ◽  
Tom Wenseleers
Keyword(s):  
Statistical Tests ◽  
Cuticular Hydrocarbon ◽  
Division Of Labour ◽  
Queen Pheromone ◽  
Worker Reproduction ◽  
Egg Laying ◽  
False Negatives ◽  
Evolutionarily Conserved ◽  
Reproductive Division Of Labour ◽  
Reproductive Division

In a recent study, Amsalem et al. performed experiments with Bombus impatiens bumblebees to test the hypothesis that saturated cuticular hydrocarbons are evolutionarily conserved signals used to regulate reproductive division of labour in many Hymenopteran social insects. They concluded that the cuticular hydrocarbon pentacosane (C25), previously identified as a queen pheromone in a congeneric bumblebee, does not affect worker reproduction in B. impatiens. Here we identify some significant shortcomings of Amsalem et al.’s study that make its conclusions unreliable. In particular, inappropriate statistical tests were used, and a reanalysis of their dataset found that C25 substantially reduced and delayed worker egg laying in B. impatiens. Additionally, the study’s low sample sizes (mean n per treatment = 13.6, range: 4-23) give it low power, not 99% power as claimed, meaning that some its non-significant results may be false negatives. Additionally, several confounding effects may have affected the results of both experimental manipulations in the study

scholarly journals Conserved queen pheromones in bumblebees: a reply to Amsalem et al.

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3332 ◽  
Author(s):  
Luke Holman ◽  
Jelle S. van Zweden ◽  
Ricardo C. Oliveira ◽  
Annette van Oystaeyen ◽  
Tom Wenseleers
Keyword(s):  
Cuticular Hydrocarbons ◽  
Statistical Tests ◽  
Cuticular Hydrocarbon ◽  
Queen Pheromone ◽  
Egg Laying ◽  
False Negatives ◽  
Queen Pheromones ◽  
Evolutionarily Conserved ◽  
Reproductive Division Of Labor ◽  
Reproductive Division

In a recent study, Amsalem, Orlova & Grozinger (2015) performed experiments withBombus impatiensbumblebees to test the hypothesis that saturated cuticular hydrocarbons are evolutionarily conserved signals used to regulate reproductive division of labor in many Hymenopteran social insects. They concluded that the cuticular hydrocarbon pentacosane (C25), previously identified as a queen pheromone in a congeneric bumblebee, does not affect worker reproduction inB. impatiens. Here we discuss some shortcomings of Amsalem et al.’s study that make its conclusions unreliable. In particular, several confounding effects may have affected the results of both experimental manipulations in the study. Additionally, the study’s low sample sizes (mean n per treatment = 13.6, range: 4–23) give it low power, not 96–99% power as claimed, such that its conclusions may be false negatives. Inappropriate statistical tests were also used, and our reanalysis found that C25substantially reduced and delayed worker egg laying inB. impatiens. We review the evidence that cuticular hydrocarbons act as queen pheromones, and offer some recommendations for future queen pheromone experiments.

scholarly journals Ant queens increase their reproductive efforts after pathogen infection

2017 ◽  
Vol 4 (7) ◽  
pp. 170547 ◽  
Author(s):  
Julia Giehr ◽  
Anna V. Grasse ◽  
Sylvia Cremer ◽  
Jürgen Heinze ◽  
Alexandra Schrempf
Keyword(s):  
Social Insect ◽  
Reproductive Effort ◽  
Reproductive Rate ◽  
Egg Laying ◽  
Reproductive Value ◽  
Reproductive Senescence ◽  
Terminal Investment ◽  
Investment In Reproduction ◽  
First Time ◽  
Investment Hypothesis

Infections with potentially lethal pathogens may negatively affect an individual's lifespan and decrease its reproductive value. The terminal investment hypothesis predicts that individuals faced with a reduced survival should invest more into reproduction instead of maintenance and growth. Several studies suggest that individuals are indeed able to estimate their body condition and to increase their reproductive effort with approaching death, while other studies gave ambiguous results. We investigate whether queens of a perennial social insect (ant) are able to boost their reproduction following infection with an obligate killing pathogen. Social insect queens are special with regard to reproduction and aging, as they outlive conspecific non-reproductive workers. Moreover, in the ant Cardiocondyla obscurior , fecundity increases with queen age. However, it remained unclear whether this reflects negative reproductive senescence or terminal investment in response to approaching death. Here, we test whether queens of C. obscurior react to infection with the entomopathogenic fungus Metarhizium brunneum by an increased egg-laying rate. We show that a fungal infection triggers a reinforced investment in reproduction in queens. This adjustment of the reproductive rate by ant queens is consistent with predictions of the terminal investment hypothesis and is reported for the first time in a social insect.

scholarly journals Conserved queen pheromones in bumblebees: A reply to Amsalem et al.

2016 ◽  
Author(s):  
Luke Holman ◽  
Jelle S van Zweden ◽  
Ricardo Caliari Oliveira ◽  
Annette van Oystaeyen ◽  
Tom Wenseleers
Keyword(s):  
Statistical Tests ◽  
Cuticular Hydrocarbon ◽  
Division Of Labour ◽  
Queen Pheromone ◽  
Worker Reproduction ◽  
Egg Laying ◽  
False Negatives ◽  
Evolutionarily Conserved ◽  
Reproductive Division Of Labour ◽  
Reproductive Division

In a recent study, Amsalem et al. performed experiments with Bombus impatiens bumblebees to test the hypothesis that saturated cuticular hydrocarbons are evolutionarily conserved signals used to regulate reproductive division of labour in many Hymenopteran social insects. They concluded that the cuticular hydrocarbon pentacosane (C25), previously identified as a queen pheromone in a congeneric bumblebee, does not affect worker reproduction in B. impatiens. Here we identify some significant shortcomings of Amsalem et al.’s study that make its conclusions unreliable. In particular, inappropriate statistical tests were used, and a reanalysis of their dataset found that C25 substantially reduced and delayed worker egg laying in B. impatiens. Additionally, the study’s low sample sizes (mean n per treatment = 13.6, range: 4-23) give it low power, not 99% power as claimed, meaning that some its non-significant results may be false negatives. Additionally, several confounding effects may have affected the results of both experimental manipulations in the study

Structure-Reactivity Relationships on Substrates and Inhibitors of the Lysine Deacylase Sirtuin 2 from Schistosoma Mansoni (SmSirt2)

2019 ◽  
Author(s):  
Daria Monaldi ◽  
Dante Rotili ◽  
Julien Lancelot ◽  
Martin Marek ◽  
Nathalie Wössner ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Human Cancer ◽  
Egg Laying ◽  
Human Cancer Cells ◽  
Parasite Survival ◽  
Survival And Reproduction ◽  
Emergence Of Resistance ◽  
First Time ◽  
Parasitic Life Cycle

The only drug for treatment of Schistosomiasis is Praziquantel, and the possible emergence of resistance makes research on novel therapeutic agents necessary. Targeting of Schistosoma mansoni epigenetic enzymes, which regulate the parasitic life cycle, emerged as promising approach. Due to the strong effects of human Sirtuin inhibitors on parasite survival and reproduction, Schistosoma sirtuins were postulated as therapeutic targets. In vitro testing of synthetic substrates of S. mansoni Sirtuin 2 (SmSirt2) and kinetic experiments on a myristoylated peptide demonstrated lysine long chain deacylation as an intrinsic SmSirt2 activity for the first time. Focused in vitro screening of the GSK Kinetobox library and structure-activity relationships (SAR) of identified hits, led to the first SmSirt2 inhibitors with activity in the low micromolar range. Several SmSirt2 inhibitors showed potency against both larval schistosomes (viability) and adult worms (pairing, egg laying) in culture without general toxicity to human cancer cells.<br>

scholarly journals Distinct colony boundaries and larval discrimination in polygyne red imported fire ants (Solenopsis invicta)

2021 ◽  
Author(s):  
MacKenzie Kjeldgaard ◽  
Pierre-André Eyer ◽  
Collin McMichael ◽  
Alison Bockoven ◽  
Joanie King ◽  
...  
Keyword(s):  
Solenopsis Invicta ◽  
Sucrose Solution ◽  
Ecological Impact ◽  
Egg Laying ◽  
Fire Ants ◽  
Fire Ant ◽  
Red Imported Fire Ant ◽  
Invasive Ant ◽  
Nestmate Discrimination ◽  
Social Forms

Evaluating the factors that promote invasive ant abundance is critical to assess their ecological impact and inform their management. Many invasive ant species show reduced nestmate recognition and an absence of boundaries between unrelated nests, which allow populations to achieve greater densities due to reduced intraspecific competition. We examined nestmate discrimination and colony boundaries in introduced populations of the red imported fire ant (Solenopsis invicta; hereafter, fire ant). Fire ants occur in two social forms: monogyne (colonies with a single egg-laying queen) and polygyne (colonies with multiple egg-laying queens). In contrast with monogyne nests, polygyne nests are thought to be interconnected due to the reduced antagonism between non-nestmate polygyne workers, perhaps because polygyne workers habituate the colony to an odor unique to Gp-9-carrying adults. However, colony boundaries and nestmate discrimination are poorly documented, particularly for worker-brood interactions. To delimit boundaries between field colonies, we correlated the exchange of a N-glycine tracer dissolved in a sucrose solution with social form. We also evaluated nestmate discrimination between polygyne workers and larvae in the laboratory. Counter to our expectations, polygyne colonies behaved identically to monogyne colonies, suggesting both social forms maintain strict colony boundaries. Polygyne workers also preferentially fed larval nestmates and may have selectively cannibalized non-nestmates. The levels of relatedness among workers in polygyne colonies was higher than those previously reported in North America (mean ±SE: 0.269 ± 0.037). Our study highlights the importance of combining genetic analyses with direct quantification of resource exchange to better understand the factors influencing ant invasions.

scholarly journals Immunoglobulins or Antibodies: IMGT® Bridging Genes, Structures and Functions

Biomedicines ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 319
Author(s):  
Marie-Paule Lefranc ◽  
Gérard Lefranc
Keyword(s):  
Homo Sapiens ◽  
Cell Receptor ◽  
Molecular Data ◽  
Dual Function ◽  
Vertebrate Species ◽  
Genomic Databases ◽  
New Science ◽  
Ig Superfamily ◽  
First Time ◽  
Imgt Unique Numbering

IMGT®, the international ImMunoGeneTics® information system founded in 1989 by Marie-Paule Lefranc (Université de Montpellier and CNRS), marked the advent of immunoinformatics, a new science at the interface between immunogenetics and bioinformatics. For the first time, the immunoglobulin (IG) or antibody and T cell receptor (TR) genes were officially recognized as ‘genes’ as well as were conventional genes. This major breakthrough has allowed the entry, in genomic databases, of the IG and TR variable (V), diversity (D) and joining (J) genes and alleles of Homo sapiens and of other jawed vertebrate species, based on the CLASSIFICATION axiom. The second major breakthrough has been the IMGT unique numbering and the IMGT Collier de Perles for the V and constant (C) domains of the IG and TR and other proteins of the IG superfamily (IgSF), based on the NUMEROTATION axiom. IMGT-ONTOLOGY axioms and concepts bridge genes, sequences, structures and functions, between biological and computational spheres in the IMGT® system (Web resources, databases and tools). They provide the IMGT Scientific chart rules to identify, to describe and to analyse the IG complex molecular data, the huge diversity of repertoires, the genetic (alleles, allotypes, CNV) polymorphisms, the IG dual function (paratope/epitope, effector properties), the antibody humanization and engineering.

Reproductive biology of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus, from the Brazilian Cerrado domain

2010 ◽  
Vol 31 (4) ◽  
pp. 463-473 ◽  
Author(s):  
Roberta Richard Pinto ◽  
Otavio Augusto Vuolo Marques ◽  
Ronaldo Fernandes
Keyword(s):  
Reproductive Biology ◽  
Sexual Maturity ◽  
Egg Production ◽  
Sympatric Species ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Brazilian Cerrado ◽  
Wet Season ◽  
Reproductive Cycles ◽  
First Time

AbstractThe reproductive biology of Chironius flavolineatus and C. quadricarinatus from the Brazilian Cerrado domain is described, including sexual maturity, female fecundity, and reproductive cycles of males and females. Egg-laying is recorded here for the first time for C. quadricarinatus. Males of both species attain sexual maturity with a smaller snout-vent length than females. Females of C. flavolineatus have an extended reproductive cycle with egg production during the wet season, whereas males exhibit year-round sperm production. Chironius quadricarinatus has continuous reproductive cycles in both sexes. Differences in reproductive pattern between these two sympatric species are probably related to phylogenetic constraints on intrageneric lineages of Chironius.

The FcγRIIa polymorphism R/H131, autoantibodies against the platelet receptors GPIbα and FcγRIIa and a risk for thromboembolism in lupus anticoagulant patients

2005 ◽  
Vol 93 (03) ◽  
pp. 544-548 ◽  
Author(s):  
Katharina Schallmoser ◽  
Christiane Rosin ◽  
Regina Knittelfelder ◽  
Thomas Sailer ◽  
Silvia Ulrich ◽  
...  
Keyword(s):  
Exploratory Study ◽  
Lupus Anticoagulant ◽  
Class Ii ◽  
Hla Class Ii ◽  
Thromboembolic Disease ◽  
Dual Function ◽  
Gene Frequencies ◽  
Close Proximity ◽  
First Time ◽  
Hla Class Ii Alleles

SummaryThere is a clear propensity of individuals with lupus anticoagulant (LA) for thromboembolic disease (TE). Yet, it is not clear how individuals at risk for TE can be differentiated from those who are not. The FcγRIIa receptor is the only Fc receptor expressed by platelets. As platelets can be activated via this receptor, we have compared gene frequencies of the FcγRIIa polymorphism R/H131 in 46 and 27 patients with (LA/TE+) and without TE (LA/TE-), respectively, in an exploratory study. Furthermore, we investigated the presence of autoantibodies against FcγRIIa and/or GPIbα, which is in close proximity to the FcγRIIa and interacts with it functionally, and a possible linkage of antibody formation to HLA class II alleles. The FcγRIIa-R/R131 genotype was significantly less frequent in patients with LA compared to controls (p< 0.025). These findings were due to an increased frequency of heterozygous patients in the LA/TE+ cohort (odds ratio 6.76, 95% confidence interval 1.55 – 62.03, p< 0.008). For the first time, heterozygosity, rather than homozygosity, can be linked to disease, which may be explained by the dual function of the FcγRIIa, namely binding of antibodies to platelets and thereby their activation, and, on the other hand, clearance of antibody coated platelets by the phagocyte system. There was no correlation between the presence of anti-FcγRIIa or anti GPIbα autoantibodies and the FcγRIIa -R/H131 polymorphism, nor the incidence of TE, nor HLA class II alleles.

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