Molecular and phenotypic diversity of the Eristalis tenax species (Diptera, Syrphidae)

Sagledavanje ukupnog genetičkog i fenotipskog diverziteta i evolucionog potencijala vrste E. tenax izvršeno je analizom jedinki poreklom sa 42 područja Evrope, Australije, Severne i Južne Amerike i laboratorijske kolonije iz Španije. Analiza intraspecijske varijabilnosti vrste E. tenax izvršena je kvantifikovanjem varijacija u veličini i obliku krila 1653 jedinke i obojenosti abdomena 936 jedinki. Analiza genetičkog diverziteta na nivou polimorfizma nukleotidnih sekvenci mtDNK je izvršena kod 58 jedinki, dok je analiza alozimske varijabilnosti obuhvatila 821 jedinku prirodnih populacija i laboratorijske kolonije vrste E. tenax. Rezultati su ukazali da inbriding i stohastički procesi utiču na redukciju genetičkog diverziteta i da “oslobađaju” skrivenu genetičku varijabilnost koja je povezana sa fenotipskom diferencijacijom. Vremenska distribucija fenotipskog diverziteta vrste E. tenax je kvantifikovana analizom jedinki četiri alohrona uzorka poreklom sa lokaliteta Venac, Fruška gora. Mali stepen genetičke i fenotipske diferencijacije između durmitorskih uzoraka vrste E. tenax ukazuje na odsustvo prostorne substruktuiranosti i njihovu međusobnu povezanost intenzivnim protokom gena. Analiza konspecifičkih populacija vrsta E. tenax ukazala je na odsustvo jasne međupopulacione diferencijacije na osnovu parametrara krila i molekularnih markera (alozimski lokusi i COI mtDNK), te se može zaključiti da postoji intenzivan protok gena koji eliminiše razlike između populacija. Registrovan je polni dimorfizam u veličini i obliku krila i obojenosti abdomena. Uočeno je da mužjaci u proseku imaju manja i uža krila i svetlije obojene abdomene od ženki. Analizom fenotipske diferencijacije u karakterima abdomena na uzorcima vrste E. tenax sakupljenim duž geografskog gradijenta Evrope je utvrđeno odsustvo promena po tipu kline. Dobijeni rezultati omogućavaju preciznije sagledavanje intra- i interpopulacione varijabilnosti ovog takona i ukazuju da vrsta E. tenax ima visok evolucioni potencijal za adaptacije na sredinske promeneThis paper examines molecular and phenotypic variability in the widely spread hoverfly species Eristalis tenax. We compared 42 samples from Europe, Australia North and South America, with the aim of obtaining insights into the temporal and spatial variations and sexual dimorphism in the species. Additionally, wild specimens from Spain were compared with a laboratory colony reared on artificial media. The integrative approach was based on allozyme loci, cytochrome c oxidase I mitochondrial DNA, morphometric wing parameters (shape and size) and abdominal colour patterns. Our results indicate that the fourth and eighth generations of the laboratory colony show a severe lack of genetic diversity compared to the figures observed in natural populations. Reduced genetic diversity in subsequent generations of the laboratory colony was found to be linked with phenotypic divergence. The distribution of genetic diversity at polymorphic loci indicated genetic divergence among collection dates from Fruška Gora Mt, and landmark-based geometric morphometrics revealed significant wing shape variation throughout the year. Phenotypic differentiation in abdominal pattern of the E. tenax populations along latitudinal gradient Europe has not been established. Consistent sexual dimorphism was observed, indicating that male specimens had lighter abdomens and smaller and narrower wings than females. It is reasonable to assume high mobility of the dronefly and high rate of gene flow reflected the similarity of genetic and phenotypic diversity of otherwise geographically distinct populations. Hence, the present study expands our knowledge of the genetic diversity and phenotypic variability of E. tenax. The quantification of such variability represents a step towards the evaluation of the adaptive potential of this species of medical and epidemiological importance

Insects in production:An introduction

Insects have been on the menu of humans for centuries, but only recently we have begun to mass produce them for human food and animal feed. This introduction first paints a synopsis of mass cultured insects and their application. The new insect production industry raises many interesting fundamental and applied questions about insect biology and fitness. The second part of the introduction to this special issue addresses the 13 articles dealing with the improvement of mass-rearing efforts for a range of insects. The various studies focus on the effects of diet and microorganisms on relevant life-history traits and economic value of the insects. They reflect the current rapid developments in the insect production industry

Effect of temperature on egg production in the common housefly

Musca domestica L. (Diptera: Muscidae), better known as the common housefly, is increasingly considered to be a new, alternative protein source for animal nutrition. By transferring low-value organic side streams into high-value protein products, its commercial production contributes to a circular economy. Next to technical innovations for scaling-up the production capacity, efficient egg production has been identified as one of the bottlenecks of housefly production systems. We investigated egg production in two strains, one originally from Spain (SPA) and one from The Netherlands (GK), at 25 and 32 °C. At 25 °C, duration of preoviposition period, laying phase, and adult longevity was longer than at 32 °C. Lifetime egg production was lower at 32 °C, but the number of clutches laid per female was unaffected by temperature. Daily egg production at 32 °C was higher during the first 7 days, revealing a trade-off between higher early-in-life reproductive effort and adult longevity. The combination of shorter sexual maturation period and higher daily egg-laying rate resulted in reaching 50% of total egg production only 6 days after emergence at 32 °C for both strains, compared to 13 and 14 days at 25 °C for SPA and GK, respectively. We conclude that, in the absence of a need for high adult survival rates, houseflies have favourable production performances at higher temperature, and that efficacy and yield of the production process could be maximized by increasing the rearing temperature to 32 °C

Fine scale population structure of hoverfly pollinator, <i>Eristalis arbustorum</i>:An integrative study

Determination of the factors influencing the population structure and adaptive tolerance to environmental pressures of the synanthropic hoverfly Eristalis arbustorum is of essential importance in understanding how pollinator populations could respond to climate change or ecosystem management. We addressed the issue of connectivity among conspecific populations sampled in Bosnia and Herzegovina. Twenty environmental factors, mitochondrial DNA sequences of the cytochrome c oxidase subunit I gene (COI mtDNA), allele frequencies at allozyme loci and wing traits (size and shape) were compared for characterization of population structure and environmental niches. Additionally, patterns of within-individual asymmetry (fluctuating asymmetry; FA) in wing size and shape within and among conspecific populations were studied. In line with the overall similarity of the environmental factors extracted for our study sites, the results of COI mtDNA diversity and STRUCTURE allozyme data provide evidence for shallow differentiation among conspecific populations. In contrast, geo-referenced Bayesian clustering methods (BAPS and GENELAND) and population-based approaches (pairwise F-ST values and AMOVA) indicate that the dispersal potential of E. arbustorum may be limited across the study area. Along with a significant FA in wing size and shape, a consistent level of FA regardless of urban/rural sampling origin is an indication of the great potential of E. arbustorum for local adaptation, because increased FA levels can be considered to be a way of expression of phenotypic variation and, hence, may contribute to adaptive responses in populations facing changing environments. Thus, by using a combined genetic-morphological approach, we significantly contributed to the understanding of the fine-scale genetic structure of the synanthropic generalist pollinator E. arbustorum

Integrative study of population structure of <i>Telestes dabar</i>, the strictly endemic cyprinid species from the Dinaric karst on the Balkan Peninsula

Diversification of the genus Telestes (Cyprinidae), endemic to the Euro-Mediterranean biogeographic subregion, mirrored an evolutionary footprint of complex biogeographical history. Hence, hidden diversity and noticeably high endemicity of freshwater ichthyofauna were discovered in the Dinaric karst on the Balkan Peninsula. One such example includes two steno-endemic Dinaric karst (Bosnia and Herzegovina) cyprinid species, Telestes dabar and T. metohiensis. Although the conservation status of T. metohiensis has been evaluated, T. dabar from Dabarsko Polje has not yet been assessed for the IUCN Red List due to its taxonomically ambiguous position and data deficiencies. Our first aim was to evaluate the resolution of taxonomic ambiguities of the two putative species, T. dabar and T. metohiensis, by the complementary use of two mitochondrial DNA markers (cytb and COI mtDNA). The results clearly demonstrated the evolutionary independence of T. dabar (Dabarsko Polje) and T. metohiensis (Nevesinjsko Polje) and confirmed the usefulness of both markers for assessing the species borders. In addition, population structure of putative T. dabar was analyzed using cytb and COI mtDNA and morphological parameters (linear measurements and landmark-based geometric morphometric data). A high genetic admixture and homogeneity in T. dabar from Dabarsko Polje were found and confirmed using both morphometric approaches as no statistically significant differences were consistently registered between different samples

Adult sex ratios affect mating behaviour in the common housefly <i>Musca domestica</i> L. (Diptera; Muscidae)

Adult sex ratio determines the level of mate availability and intrasexual competition for each sex. Sex ratio biases have been proposed to enhance the productivity of animal rearing procedures. However, behaviour may change in response to sex ratio manipulations that may counteract potential benefits. We investigated how sex ratios affected mating behaviour of the housefly Musca domestica, a species used in the animal feed industry. We hypothesized a reduced courtship effort and mating latency and increased ejaculate allocation (copulation duration) under male-biased sex ratios, whereas female-biased sex ratios would lead to the opposite effects. However, courtship effort was reduced in female-biased groups, implying reduced male harassment. Mating latency was lower and copulation lasted longer in female-biased groups, which may reduce reproduction time and increase female fecundity and lifespan. Our results indicate that in houseflies, female-biased sex ratios cause behavioural changes in both sexes that could positively contribute to reproductive output

Adult sex ratios affect mating behaviour in the common housefly <i>Musca domestica</i> L. (Diptera; Muscidae)

Adult sex ratio determines the level of mate availability and intrasexual competition for each sex. Sex ratio biases have been proposed to enhance the productivity of animal rearing procedures. However, behaviour may change in response to sex ratio manipulations that may counteract potential benefits. We investigated how sex ratios affected mating behaviour of the housefly Musca domestica, a species used in the animal feed industry. We hypothesized a reduced courtship effort and mating latency and increased ejaculate allocation (copulation duration) under male-biased sex ratios, whereas female-biased sex ratios would lead to the opposite effects. However, courtship effort was reduced in female-biased groups, implying reduced male harassment. Mating latency was lower and copulation lasted longer in female-biased groups, which may reduce reproduction time and increase female fecundity and lifespan. Our results indicate that in houseflies, female-biased sex ratios cause behavioural changes in both sexes that could positively contribute to reproductive output

Molecular and phenotypic diversity of the Eristalis tenax species (Diptera, Syrphidae)

Sagledavanje ukupnog genetičkog i fenotipskog diverziteta i evolucionog potencijala vrste E. tenax izvršeno je analizom jedinki poreklom sa 42 područja Evrope, Australije, Severne i Južne Amerike i laboratorijske kolonije iz Španije. Analiza intraspecijske varijabilnosti vrste E. tenax izvršena je kvantifikovanjem varijacija u veličini i obliku krila 1653 jedinke i obojenosti abdomena 936 jedinki. Analiza genetičkog diverziteta na nivou polimorfizma nukleotidnih sekvenci mtDNK je izvršena kod 58 jedinki, dok je analiza alozimske varijabilnosti obuhvatila 821 jedinku prirodnih populacija i laboratorijske kolonije vrste E. tenax. Rezultati su ukazali da inbriding i stohastički procesi utiču na redukciju genetičkog diverziteta i da “oslobađaju” skrivenu genetičku varijabilnost koja je povezana sa fenotipskom diferencijacijom. Vremenska distribucija fenotipskog diverziteta vrste E. tenax je kvantifikovana analizom jedinki četiri alohrona uzorka poreklom sa lokaliteta Venac, Fruška gora. Mali stepen genetičke i fenotipske diferencijacije između durmitorskih uzoraka vrste E. tenax ukazuje na odsustvo prostorne substruktuiranosti i njihovu međusobnu povezanost intenzivnim protokom gena. Analiza konspecifičkih populacija vrsta E. tenax ukazala je na odsustvo jasne međupopulacione diferencijacije na osnovu parametrara krila i molekularnih markera (alozimski lokusi i COI mtDNK), te se može zaključiti da postoji intenzivan protok gena koji eliminiše razlike između populacija. Registrovan je polni dimorfizam u veličini i obliku krila i obojenosti abdomena. Uočeno je da mužjaci u proseku imaju manja i uža krila i svetlije obojene abdomene od ženki. Analizom fenotipske diferencijacije u karakterima abdomena na uzorcima vrste E. tenax sakupljenim duž geografskog gradijenta Evrope je utvrđeno odsustvo promena po tipu kline. Dobijeni rezultati omogućavaju preciznije sagledavanje intra- i interpopulacione varijabilnosti ovog takona i ukazuju da vrsta E. tenax ima visok evolucioni potencijal za adaptacije na sredinske promeneThis paper examines molecular and phenotypic variability in the widely spread hoverfly species Eristalis tenax. We compared 42 samples from Europe, Australia North and South America, with the aim of obtaining insights into the temporal and spatial variations and sexual dimorphism in the species. Additionally, wild specimens from Spain were compared with a laboratory colony reared on artificial media. The integrative approach was based on allozyme loci, cytochrome c oxidase I mitochondrial DNA, morphometric wing parameters (shape and size) and abdominal colour patterns. Our results indicate that the fourth and eighth generations of the laboratory colony show a severe lack of genetic diversity compared to the figures observed in natural populations. Reduced genetic diversity in subsequent generations of the laboratory colony was found to be linked with phenotypic divergence. The distribution of genetic diversity at polymorphic loci indicated genetic divergence among collection dates from Fruška Gora Mt, and landmark-based geometric morphometrics revealed significant wing shape variation throughout the year. Phenotypic differentiation in abdominal pattern of the E. tenax populations along latitudinal gradient Europe has not been established. Consistent sexual dimorphism was observed, indicating that male specimens had lighter abdomens and smaller and narrower wings than females. It is reasonable to assume high mobility of the dronefly and high rate of gene flow reflected the similarity of genetic and phenotypic diversity of otherwise geographically distinct populations. Hence, the present study expands our knowledge of the genetic diversity and phenotypic variability of E. tenax. The quantification of such variability represents a step towards the evaluation of the adaptive potential of this species of medical and epidemiological importance