Dinner and a show : the role of male copulatory courtship song and female blood-feeding in the reproductive success of Lutzomyia longipalpis from Lapinha, Brazil

The work was supported by CNPq (Science without Borders program) and CAPES.Lutzomyia longipalpis is the main vector of visceral Leishmaniasis in the Americas and is composed of a species complex. Males of this sand-fly produce acoustic signals during copulation and different patterns are observed among Brazilian populations. Such acoustic signals are commonly involved in species recognition. However, since the song is only produced during copulation it is not clear how it affects mating success or contributes to sexual isolation. Another aspect that may affect reproductive success is the presence of food. Since hematophagy is such an important aspect of L. longipalpis biology, we wanted to test if blood-feeding can influence the reproductive behaviour of this insect. We performed crossing experiments removing males' wings (silencing them) and playing back either the homo-specific or the hetero-specific song to either unfed or blood-fed females. Our results showed that both songs and blood-feeding affect insemination success, but not the frequency of copulation. In trials where females were not blood-fed song clearly affected insemination; males with wings, and males with homo-specific song playback had a higher insemination success than wingless males (no song) and trials with hetero-specific song. Blood-feeding females prior to the trials increased insemination in all groups including the control group which suggests that mating happens simultaneously with, or immediately after, the blood meal. Blood-fed females also seemed to discriminate less against the wrong song or the lack of song (wingless) one day after feeding, however trials with the correct song still had higher insemination rates. Altogether, our results show that both the male copulatory courtship songs and female blood-feeding are important for reproductive success and as such are important components of the sexual behaviour of L. longipalpis.PostprintPeer reviewe

Phenotypic differentiation in love song traits among sibling species of the lutzomyia longipalpis complex in Brazil

Brazilian populations of Lutzomyia longipalpis may constitute a complex of cryptic species, and this report investigates the distribution and number of potential sibling species. One of the main differences observed among Brazilian populations is the type of acoustic signal produced by males during copulation. These copulation song differences seem to be evolving faster than neutral molecular markers and have been suggested to contribute to insemination failure observed in crosses between these sibling species. In previous studies, two main types of copulation songs were found, burst-type and pulse-type. The latter type can, in turn, be further subdivided into five different patterns. Methods We recorded male song from 13 new populations of the L. longipalpis complex from Brazil and compared the songs with 12 already available. Results Out of these 25 populations, 16 produce burst-type and 9 produce pulse-type songs. We performed a principal component analysis in these two main groups separately and an additional discriminant analysis in the pulse-type group. The pulse-type populations showed a clear separation between the five known patterns with a high correspondence of individuals to their correct group, confirming the differentiation between them. The distinctiveness of the burst-type subgroups was much lower than that observed among the pulse-type groups and no clear population structure was observed. This suggests that the burst-type populations represent a single species. Conclusion Overall, our results are consistent with the existence in Brazil of at least six species of the L. longipalpis complex, one with a wide distribution comprising all the populations with burst-type songs, and five more closely related allopatric siblings with different pulse-type song patterns and more restricted distribution ranges8CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informaçã

Oviposition but not sex allocation is associated with transcriptomic changes in females of the parasitoid wasp Nasonia vitripennis

This work was supported by Natural Environment Research Council (NERC) grant (NE/J024481/1). DMS was previously funded by a NERC Advanced Research Fellowship.Linking the evolution of the phenotype to the underlying genotype is a key aim of evolutionary genetics and is crucial to our understanding of how natural selection shapes a trait. Here we consider the genetic basis of sex allocation behaviour in the parasitoid wasp Nasonia vitripennis using a transcriptomics approach. Females allocate offspring sex in line with Local Mate Competition (LMC) theory. Female-biased sex ratios are produced when one or few females lay eggs on a patch. As the number of females contributing offspring to a patch increases, less female-biased sex ratios are favoured. We contrasted the transcriptomic responses of females as they oviposit under conditions known to influence sex allocation: foundress number (a social cue) and the state of the host (parasitised or not). We found, that when females encounter other females on a patch, or assess host quality with their ovipositors, the resulting changes in sex allocation is not associated with significant changes in whole-body gene expression. We also found that the gene expression changes produced by females, as they facultatively allocate sex in response to a host cue and a social cue, are very closely correlated. We expanded the list of candidate genes associated with oviposition behaviour in Nasonia, some of which may be involved in fundamental processes underlying the ability to facultatively allocate sex, including sperm storage and utilisation.Publisher PDFPeer reviewe

Differential gene expression is not required for facultative sex allocation:a transcriptome analysis of brain tissue in the parasitoid wasp <i>Nasonia vitripennis</i>

Table S1: Mapping statistics for all sequenced librarie

A decade of stability for wMel Wolbachia in natural Aedes aegypti populations

Mosquitoes carrying Wolbachia endosymbionts are being released in many countries for arbovirus control. The wMel strain of Wolbachia blocks Aedes-borne virus transmission and can spread throughout mosquito populations by inducing cytoplasmic incompatibility. Aedes aegypti mosquitoes carrying wMel were first released into the field in Cairns, Australia, over a decade ago, and with wider releases have resulted in the near elimination of local dengue transmission. The long-term stability of Wolbachia effects is critical for ongoing disease suppression, requiring tracking of phenotypic and genomic changes in Wolbachia infections following releases. We used a combination of field surveys, phenotypic assessments, and Wolbachia genome sequencing to show that wMel has remained stable in its effects for up to a decade in Australian Ae. aegypti populations. Phenotypic comparisons of wMel-infected and uninfected mosquitoes from near-field and long-term laboratory populations suggest limited changes in the effects of wMel on mosquito fitness. Treating mosquitoes with antibiotics used to cure the wMel infection had limited effects on fitness in the next generation, supporting the use of tetracycline for generating uninfected mosquitoes without off-target effects. wMel has a temporally stable within-host density and continues to induce complete cytoplasmic incompatibility. A comparison of wMel genomes from pre-release (2010) and nine years post-release (2020) populations show few genomic differences and little divergence between release locations, consistent with the lack of phenotypic changes. These results indicate that releases of Wolbachia-infected mosquitoes for population replacement are likely to be effective for many years, but ongoing monitoring remains important to track potential evolutionary changes

Counting the bodies: Estimating the numbers and spatial variation of Australian reptiles, birds and mammals killed by two invasive mesopredators

Aim Introduced predators negatively impact biodiversity globally, with insular fauna often most severely affected. Here, we assess spatial variation in the number of terrestrial vertebrates (excluding amphibians) killed by two mammalian mesopredators introduced to Australia, the red fox (Vulpes vulpes) and feral cat (Felis catus). We aim to identify prey groups that suffer especially high rates of predation, and regions where losses to foxes and/or cats are most substantial. Location Australia. Methods We draw information on the spatial variation in tallies of reptiles, birds and mammals killed by cats in Australia from published studies. We derive tallies for fox predation by (i) modelling continental-scale spatial variation in fox density, (ii) modelling spatial variation in the frequency of occurrence of prey groups in fox diet, (iii) analysing the number of prey individuals within dietary samples and (iv) discounting animals taken as carrion. We derive point estimates of the numbers of individuals killed annually by foxes and by cats and map spatial variation in these tallies. Results Foxes kill more reptiles, birds and mammals (peaking at 1071 km−2 year−1) than cats (55 km−2 year−1) across most of the unmodified temperate and forested areas of mainland Australia, reflecting the generally higher density of foxes than cats in these environments. However, across most of the continent – mainly the arid central and tropical northern regions (and on most Australian islands) – cats kill more animals than foxes. We estimate that foxes and cats together kill 697 million reptiles annually in Australia, 510 million birds and 1435 million mammals. Main conclusions This continental-scale analysis demonstrates that predation by two introduced species takes a substantial and ongoing toll on Australian reptiles, birds and mammals. Continuing population declines and potential extinctions of some of these species threatens to further compound Australia's poor contemporary conservation record

The Interaction of N-Acylhomoserine Lactone Quorum Sensing Signaling Molecules with Biological Membranes: Implications for Inter-Kingdom Signaling

The long chain N-acylhomoserine lactone (AHL) quorum sensing signal molecules released by Pseudomonas aeruginosa have long been known to elicit immunomodulatory effects through a process termed inter-kingdom signaling. However, to date very little is known regarding the exact mechanism of action of these compounds on their eukaryotic targets.The use of the membrane dipole fluorescent sensor di-8-ANEPPS to characterise the interactions of AHL quorum sensing signal molecules, N-(3-oxotetradecanoyl)-L-homoserine lactone (3-oxo-C14-HSL), N-(3-oxododecanoyl)homoserine-L-lactone (3-oxo-C12-HSL) and N-(3-oxodecanoyl) homoserine-L-lactone (3-oxo-C10 HSL) produced by Pseudomonas aeruginosa with model and cellular membranes is reported. The interactions of these AHLs with artificial membranes reveal that each of the compounds is capable of membrane interaction in the micromolar concentration range causing significant modulation of the membrane dipole potential. These interactions fit simple hyperbolic binding models with membrane affinity increasing with acyl chain length. Similar results were obtained with T-lymphocytes providing the evidence that AHLs are capable of direct interaction with the plasma membrane. 3-oxo-C12-HSL interacts with lymphocytes via a cooperative binding model therefore implying the existence of an AHL membrane receptor. The role of cholesterol in the interactions of AHLs with membranes, the significance of modulating cellular dipole potential for receptor conformation and the implications for immune modulation are discussed.Our observations support previous findings that increasing AHL lipophilicity increases the immunomodulatory activity of these quorum compounds, while providing evidence to suggest membrane interaction plays an important role in quorum sensing and implies a role for membrane microdomains in this process. Finally, our results suggest the existence of a eukaryotic membrane-located system that acts as an AHL receptor

Conflict and user involvement in drug misuse treatment decision-making: a qualitative study

<p>Abstract</p> <p>Background</p> <p>This paper examines client/staff conflict and user involvement in drug misuse treatment decision-making.</p> <p>Methods</p> <p>Seventy-nine in-depth interviews were conducted with new treatment clients in two residential and two community drug treatment agencies. Fifty-nine of these clients were interviewed again after twelve weeks. Twenty-seven interviews were also conducted with staff, who were the keyworkers for the interviewed clients.</p> <p>Results</p> <p>Drug users did not expect, desire or prepare for conflict at treatment entry. They reported few actual conflicts within the treatment setting, but routinely discussed latent conflicts – that is, negative experiences and problematic aspects of current or previous treatment that could potentially escalate into overt disputes. Conflict resulted in a number of possible outcomes, including the premature termination of treatment; staff deciding on the appropriate outcome; the client appealing to the governance structure of the agency; brokered compromise; and staff skilfully eliciting client consent for staff decisions.</p> <p>Conclusion</p> <p>Although the implementation of user involvement in drug treatment decision-making has the potential to trigger high levels of staff-client conflict, latent conflict is more common than overt conflict and not all conflict is negative. Drug users generally want to be co-operative at treatment entry and often adopt non-confrontational forms of covert resistance to decisions about which they disagree. Staff sometimes deploy user involvement as a strategy for managing conflict and soliciting client compliance to treatment protocols. Suggestions for minimising and avoiding harmful conflict in treatment settings are given.</p