Wild-caught Females Research Articles

Fertility differences between two wild-type Drosophila melanogaster lines correlate with differences in the expression of the Jheh1 gene, which codes for an enzyme degrading juvenile hormone.

Juvenile hormone plays a "status quo" role in Drosophila melanogaster larvae, preventing the untimely metamorphosis, and performs a gonadotropic function in imagoes, ensuring the ovaries' preparedness for vitellogenesis. The decreased level of juvenile hormone results in reproductive disorders in D. melanogaster females including a delay in the oviposition onset and a fertility decrease. Another factor that can affect the insect reproduction is an infection with the maternally inherited symbiotic α-proteobacterium Wolbachia. The present study is devoted to the analysis of the expression of two juvenile hormone metabolism genes encoding enzymes of its synthesis and degradation, juvenile hormone acid O-methyltransferase ( jhamt) and juvenile hormone epoxide hydrase (Jheh1), respectively, in four wild-type D. melanogaster lines, two of them being infected with Wolbachia. Lines w153 and Bi90 were both derived from an individual wild-caught females infected with Wolbachia, while lines w153T and Bi90T were derived from them by tetracycline treatment and are free of infection. Line Bi90 is known to be infected with the Wolbachia strain wMel, and line w153, with the Wolbachia strain wMelPlus belonging to the wMelCS genotype. It was found that infection with either Wolbachia strain does not affect the expression of the studied genes. At the same time, it was shown that the w153 and w153T lines differ from the Bi90 and Bi90T lines by an increased level of the Jheh1 gene expression and do not differ in the jhamt gene expression level. Analysis of the fertility of these four lines showed that it does not depend on Wolbachia infection either, but differs between lines with different nuclear genotypes: in w153 and w153T, it is significantly lower than in lines Bi90 and Bi90T. The data obtained allow us to reasonably propose that the inter-line D. melanogaster polymorphism in the metabolism of the juvenile hormone is determined by its degradation (not by its synthesis) and correlates with the fertility level.

Paternity Analyses for the Planning of SIT Projects against the Red Palm Weevil

The red palm weevil Rhynchophorus ferrugineus is an invasive pest from southeastern Asia and Melanesia that has spread widely across the Middle East and the Mediterranean Basin over the last 30 years. Its endophagous larvae cause huge amounts of damage to several palm tree species from the Arecaceae family. Many of these palms are economically important for agricultural and ornamental purposes. Therefore, a lot of attention has recently been focused on studying this species with the aim of identifying sustainable and effective eradication strategies. Sterile insect techniques are biological control strategies that are currently being investigated for their potential to eradicate this pest in selected invasion areas. Mating system features (e.g., polyandry and related features) can affect the success and suitability of these approaches. The main goal of this research was to assess the performance of a previously developed microsatellite panel in terms of the paternity assignment of progeny from laboratory mating experiments. Using a simulation approach, we evaluated the reliability of the microsatellite markers in the paternity tests both in complex laboratory experiment scenarios and on the progeny of wild-caught gravid females to help future studies on the RPW mating system. As a case study of the simulation results, we performed two double-mating experiments, genotyped the progeny and estimated the P2 values to compare to the expected progeny genotypes according to the crossing scheme of each experiment. The results of our simulations on laboratory experiments showed that it was possible to carry out paternity assignments for all progeny with reliable statistical confidence using our 13 microsatellites set. On the contrary the low genetic variability measured in red palm weevil populations in invaded areas made the resolution power of our loci too low to carry out paternity analyses on natural populations. Results of laboratory crossing were completely congruent with the expectations from the Mendelian laws.

Cryopreservation of sperm in the spotted scat, Scatophagus argus (Linnaeus, 1766) - Conservation and aquaculture perspectives

This study emphasizes the need for sperm quality assessment and cryopreservation strategy in the spotted scat Scatophagus argus as the occurrence of male population of this species is limited. Analyses of sperm quality were made including ionic content and osmolality of seminal plasma and blood serum. Sodium chloride (0.9%) was optimized as the extender with a dilution ratio of 1:3 (milt:cryomedium) for all experiments. Cryoprotectants including dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), glycerol (GLY), propylene glycol (PG), ethylene glycol (EG) and methanol (MeOH) were screened at various concentrations and equilibration times. Cryopreservation was performed using the cryoprotectants DMSO, GLY, EG, and MeOH individually as well as in combinations. Experiment 1 was done with DMSO, GLY, EG and MeOH (5, 10 and 15%); experiment 2 was done with DMSO (5%) + GLY (5%), DMSO (5%) + EG (5%), DMSO (5%) + MeOH (5%). Simultaneously, experiment 3 was done with both cryoprotectants and co-cryoprotectants viz. DMSO (5%) + egg yolk (5%), DMSO (5%) + coconut water (5%), DMSO (5%) + tomato water (5%) and DMSO (5%) + honey (5%). The cooling sample was optimized and performed with a one-step freezing protocol of −5 °C/min from 25 °C to −150 °C. The results indicated that samples subjected to experiment 2 using DMSO (5%) + EG (5%) for 60 days of storage registered maximum motility (82.33 ± 2.51%), duration time of sperm motility (10.45± 1.01 min) and viability (84.14 ± 5.29%) of post-thaw cryopreserved sperm. Morphology and ultrastructure of post-thaw sperm showed smooth surface topography and normal architecture of cellular organelles. Biochemical analysis indicated a reduction in the protein content of post-thaw cryopreserved sperm. DNA integrity (Comet assay) showed 6.30 ± 1.00% of tail DNA in post-thaw sperm, whereas fresh sperm registered 2.41 ± 1.85%. Functional integrity using the HOST of post-thaw sperm showed a maximum of 82.66 ± 1.15% with DMSO (5%) + EG (5%). Finally, fertility of post-thaw sperm using mature eggs of wild-caught females indicated the entry of sperm by breaking the vitelline membrane. Overall it was demonstrated that the DMSO (5%) + EG (5%) was amenable to the long-term preservation of sperm. Therefore, this protocol can be used as an alternative for male broodstock development under captive breeding program.

Short-term artificial incubation before hatching limits vertical transmission of Aphanomyces astaci from chronically infected females of a host species susceptible to crayfish plague

Crayfish plague, caused by the oomycete Aphanomyces astaci and spread primarily by its original crayfish hosts from North America, not only threatens populations of endangered crayfish but also impacts their fisheries and aquaculture. This includes the narrow-clawed crayfish (Pontastacus leptodactylus) in Turkey, where its fishery and export used to grow until the mid-1980s when the accidental introduction of crayfish plague caused stock collapses. Although crayfish densities in some Turkish lakes returned to levels where fishery is feasible, persistent chronic infections by A. astaci prevent full crayfish population recovery and stock exploitation. The establishment of closed culturing systems faces the problem of substantial mortality of both broodstock and juveniles originating from the wild, apparently associated with the stress-induced development of crayfish plague symptoms. In our experiment, we evaluated whether A. astaci is vertically transmitted to juveniles during maternal incubation, and to what extent hatching of crayfish eggs in artificial conditions, coupled with antifungal baths, limits the infection by this pathogen. Egg-carrying (berried) crayfish females were caught from the Lake Eğirdir, Turkey, shortly before juvenile hatching. Eggs stripped from females were assigned into four experimental groups: two groups were treated with antifungal baths (formaldehyde or peracetic acid), the other two groups were controls kept without antifungal treatment but set up in conditions differing in the likelihood of accidental A. astaci transmission. Eggs on five berried females were kept for maternal incubation. The results confirmed that nearly all wild-caught females tested for the presence of A. astaci DNA by quantitative PCR were infected, and A. astaci infections were frequently confirmed in the maternally incubated juveniles. In contrast, we did not confirm unambiguous A. astaci infection in any juvenile from eggs treated by antifungal baths and from one of the control groups, which were all kept on a strictly separated flow-through system. However, juveniles from the control group on a recirculating system, in which also infected crayfish (e.g., maternal incubation group) were present, suffered elevated mortality, likely related to the accidental introduction of the pathogen that was confirmed in this treatment. The separation of the eggs from infected mothers before hatching apparently substantially reduces pathogen vertical transmission, and combination with an antifungal treatment further increases juvenile survival. Although it cannot be guaranteed that the juveniles that hatched and developed in artificial conditions are entirely A. astaci-free, the approach seems suitable for routine aquaculture applications in regions where chronic infections by this pathogen are widespread.

Differential expression of Phlebotomus tobbi Adler, Theodor & Lourie, 1930 (Diptera: Psychodidae) genes under different environmental conditions

Phlebotomus tobbi is a widely distributed sand fly species in Turkey and is the proven vector of Leishmania infantum and several Phleboviruses. Information regarding the genetic basis of phenotypic plasticity is crucial for managing vector-borne diseases, as the changing environmental conditions have consequences for the survival of arthropods and the disease agents they transmit. However, limited data is available on the impacts of environmental conditions on the traits associated with sand fly survival, reproduction, and vectorial competence. The present study aimed to reveal the changes in the expression levels of three selected P. tobbi genes using laboratory-reared and wild-caught populations. A nervous system protein, Cacophony (PtCac), related to the life history traits of sand flies, and two sand fly salivary protein genes, PtSP32 and PtSP38, influence the infection of the vertebrate hosts, were assessed. Sand flies were maintained at 23 °C and 27 °C in the laboratory to evaluate the relationship between temperature and the expressed phenotypes. Field collections were carried out in three climatically distinct regions of Turkey to establish the regional differences in the gene expression levels of natural P. tobbi populations. In the laboratory, PtCac expression increased with the temperature. However, PtCac expression was negatively correlated with local temperature and humidity conditions. No differences were detected in the PtSP32 gene expression levels of both laboratory-reared and wild-caught females, but a negative correlation was observed with relative humidity in natural populations. Although the expression levels of PtSP38 did not differ among the females collected from distinct regions, a positive correlation was detected in the laboratory-reared colony. The findings indicated that changes in environmental conditions could drive the expression levels of P. tobbi genes, which influence population dynamics and the transmission risk of the disease.

Paternity sharing in insects with female competition for nuptial gifts.

Male parental investment is expected to be associated with high confidence of paternity. Studies of species with exclusive male parental care have provided support for this hypothesis because mating typically co-occurs with each oviposition, allowing control over paternity and the allocation of care. However, in systems where males invest by feeding mates (typically arthropods), mating (and thus the investment) is separated from egg-laying, resulting in less control over insemination, as male ejaculates compete with rival sperm stored by females, and a greater risk of investing in unrelated offspring (cuckoldry). As strong selection on males to increase paternity would compromise the fitness of all a female's other mates that make costly nutrient contributions, paternity sharing (males not excluded from siring offspring) is an expected outcome of sperm competition. Using wild-caught females in an orthopteran and a dipteran species, in which sexually selected, ornamented females compete for male nuptial food gifts needed for successful reproduction, we examined paternity patterns and compared them with findings in other insects. We used microsatellite analysis of offspring (lifetime reproduction in the orthopteran) and stored sperm from wild-caught females in both study species. As predicted, there was evidence of shared paternity as few males failed to sire offspring. Further support for paternity sharing is the lack of last-male sperm precedence in our study species. Although paternity was not equal among sires, our estimates of paternity bias were similar to other insects with valuable nuptial gifts and contrasted with the finding that males are frequently excluded from siring offspring in species where males supply little more than sperm. This suggests paternity bias may be reduced in nuptial-gift systems and may help facilitate the evolution of these paternal investments.

Ova lipid profiling and egg quality in wild and captive lumpfish, Cyclopterus lumpus (Linnaeus, 1758)

Lumpfish (Cyclopterus lumpus) serves an important role as cleaner fish for removing salmon lice in salmon aquaculture. For this use, cultivated lumpfish are preferred over wild-caught fish to avoid overexploitation of natural stocks and provide a stable production of good quality eggs and larvae. To support this, high quality eggs containing the necessary building blocks to support high fertilization success, development into a normal embryo and high hatching success is needed. Ova from wild-caught and captive lumpfish females were collected and assessed to identify how wild and domesticated lumpfish differ in terms of ova lipid profiles, egg and larvae quality. Wild-caught lumpfish displayed higher fertilization and hatching success compared to captive lumpfish, whereas other biological variables like egg size, egg/larvae dry weight and respiration, and larval morphometry, were not significantly different between wild and captive lumpfish. Ova lipid profiles (total lipid, lipid classes, fatty acid composition and lipidomics) can separate egg batches based on their geographic origin of wild-caught females and composition of diets used for captive broodstock (lipid and carbohydrate content). Multivariate statistics were applied to identify lipid markers that can be used to predict the quality of lumpfish ova. Lumpfish ova lipidomic profiles covaried with several biological parameters, indicating that the former can be used to predict the latter. Lumpfish eggs were mostly composed of triacylglycerides (TAGs) with some phosphatidylethanolamines (PEs) and phosphatidylcholines (PCs), and their lipid profiles were more sensitive to the different origins, mother weight/size and fertilization success than variables such as eggs size or larvae morphometric measures. PC and PE content of lumpfish eggs were positively correlated to both hatching success and fertilization rates, thus the lipidomic profiles, with some key highlighted lipid species were putative predictors of egg quality.

A high-quality de novo genome assembly based on nanopore sequencing of a wild-caught coconut rhinoceros beetle (Oryctes rhinoceros)

BackgroundAn optimal starting point for relating genome function to organismal biology is a high-quality nuclear genome assembly, and long-read sequencing is revolutionizing the production of this genomic resource in insects. Despite this, nuclear genome assemblies have been under-represented for agricultural insect pests, particularly from the order Coleoptera. Here we present a de novo genome assembly and structural annotation for the coconut rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), based on Oxford Nanopore Technologies (ONT) long-read data generated from a wild-caught female, as well as the assembly process that also led to the recovery of the complete circular genome assemblies of the beetle’s mitochondrial genome and that of the biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). As an invasive pest of palm trees, O. rhinoceros is undergoing an expansion in its range across the Pacific Islands, requiring new approaches to management that may include strategies facilitated by genome assembly and annotation.ResultsHigh-quality DNA isolated from an adult female was used to create four ONT libraries that were sequenced using four MinION flow cells, producing a total of 27.2 Gb of high-quality long-read sequences. We employed an iterative assembly process and polishing with one lane of high-accuracy Illumina reads, obtaining a final size of the assembly of 377.36 Mb that had high contiguity (fragment N50 length = 12 Mb) and accuracy, as evidenced by the exceptionally high completeness of the benchmarked set of conserved single-copy orthologous genes (BUSCO completeness = 99.1%). These quality metrics place our assembly ahead of the published Coleopteran genomes, including that of an insect model, the red flour beetle (Tribolium castaneum). The structural annotation of the nuclear genome assembly contained a highly-accurate set of 16,371 protein-coding genes, with only 2.8% missing BUSCOs, and the expected number of non-coding RNAs. The number and structure of paralogous genes in a gene family like Sigma GST is lower than in another scarab beetle (Onthophagus taurus), but higher than in the red flour beetle (Tribolium castaneum), which suggests expansion of this GST class in Scarabaeidae. The quality of our gene models was also confirmed with the correct placement of O. rhinoceros among other members of the rhinoceros beetles (subfamily Dynastinae) in a phylogeny based on the sequences of 95 protein-coding genes in 373 beetle species from all major lineages of Coleoptera. Finally, we provide a list of 30 candidate dsRNA targets whose orthologs have been experimentally validated as highly effective targets for RNAi-based control of several beetles.ConclusionsThe genomic resources produced in this study form a foundation for further functional genetic research and management programs that may inform the control and surveillance of O. rhinoceros populations, and we demonstrate the efficacy of de novo genome assembly using long-read ONT data from a single field-caught insect.

Microbiota Variation Across Life Stages of European Field-Caught Anopheles atroparvus and During Laboratory Colonization: New Insights for Malaria Research.

The potential use of bacteria for developing novel vector control approaches has awakened new interests in the study of the microbiota associated with vector species. To set a baseline for future malaria research, a high-throughput sequencing of the bacterial 16S ribosomal gene V3-V4 region was used to profile the microbiota associated with late-instar larvae, newly emerged females, and wild-caught females of a sylvan Anopheles atroparvus population from a former malaria transmission area of Spain. Field-acquired microbiota was then assessed in non-blood-fed laboratory-reared females from the second, sixth, and 10th generations. Diversity analyses revealed that bacterial communities varied and clustered differently according to origin with sylvan larvae and newly emerged females distributing closer to laboratory-reared females than to their field counterparts. Inter-sample variation was mostly observed throughout the different developmental stages in the sylvan population. Larvae harbored the most diverse bacterial communities; wild-caught females, the poorest. In the transition from the sylvan environment to the first time point of laboratory breeding, a significant increase in diversity was observed, although this did decline under laboratory conditions. Despite diversity differences between wild-caught and laboratory-reared females, a substantial fraction of the bacterial communities was transferred through transstadial transmission and these persisted over 10 laboratory generations. Differentially abundant bacteria were mostly identified between breeding water and late-instar larvae, and in the transition from wild-caught to laboratory-reared females from the second generation. Our findings confirmed the key role of the breeding environment in shaping the microbiota of An. atroparvus. Gram-negative bacteria governed the microbiota of An. atroparvus with the prevalence of proteobacteria. Pantoea, Thorsellia, Serratia, Asaia, and Pseudomonas dominating the microbiota associated with wild-caught females, with the latter two governing the communities of laboratory-reared females. A core microbiota was identified with Pseudomonas and Serratia being the most abundant core genera shared by all sylvan and laboratory specimens. Overall, understanding the microbiota composition of An. atroparvus and how this varies throughout the mosquito life cycle and laboratory colonization paves the way when selecting potential bacterial candidates for use in microbiota-based intervention strategies against mosquito vectors, thereby improving our knowledge of laboratory-reared An. atroparvus mosquitoes for research purposes.

Social partner cooperativeness influences brain oxytocin transcription in Trinidadian guppies (Poecilia reticulata)

For non-kin cooperation to be maintained, individuals need to respond adaptively to the cooperative behaviour of their social partners. Currently, however, little is known about the biological responses of individuals to experiencing cooperation. Here, we quantify the neuroregulatory response of Trinidadian guppies (Poecilia reticulata) experiencing cooperation or defection by examining the transcriptional response of the oxytocin gene (oxt; also known as isotocin), which has been implicated in cooperative decision-making. We exposed wild-caught females to social environments where partners either cooperated or defected during predator inspection, or to a control (non-predator inspection) context, and quantified the relative transcription of the oxt gene. We tested an experimental group, originating from a site where individuals are under high predation threat and have previous experience of large aquatic predators (HP), and a control group, where individuals are under low predation threat and naïve to large aquatic predators (LP). LP, but not HP, fish showed different behavioural responses to the behaviour of their social environment, cooperating with cooperative partners and defecting when paired with defecting ones. In HP, but not LP, fish brain mid-section oxt relative transcription varied depending on social partner behaviour. HP fish experiencing cooperation during predator inspection had lower oxt transcription than those experiencing defection. This effect was not present in the control population or in the control context, where the behaviour of social partners did not affect oxt transcription. Our findings provide insight into the neuromodulation underpinning behavioural responses to social experiences, and ultimately to the proximate mechanisms underlying social decision-making.

Decision-making at the time of parasitism: cowbirds prefer to peck eggs with weaker shells.

Interspecific avian brood parasites, like cuckoos and cowbirds, lay their eggs in nests of other species, the hosts, which take over the entire parental care of the parasite's eggs and chicks. This breeding strategy requires decisions that may affect the parasite's reproductive success. During the breeding season, cowbirds search for host nests and revisit them to monitor its progress and parasitize at the time host laying begins. When visiting hosts nests, they repeatedly peck the nest contents trying to destroy one or more eggs. This behaviour favours parasite's offspring by reducing the competition for food with nestmates. We evaluated if the egg-pecking behaviour of female shiny (Molothrus bonariensis) and screaming (M. rufoaxillaris) cowbirds is affected by the strength and the size of the eggs they find in the nest. We presented to wild-caught females artificial clutches with two natural eggs that differ in size and shell strength. We found that female shiny and screaming cowbirds adjusted egg-pecking behaviour based on the strength but not on the size of the eggs. When differences in strength between eggs were high, both cowbird species pecked more frequently the egg with the weaker shell, increasing the probability of a successful puncture. Our results indicate that female cowbirds can discriminate eggs through the strength of the shell, and by choosing the weaker egg to peck, they increase the probability of puncturing.

Seasonal changes and endocrine regulation of gonadal development in hatchery-produced Pacific bluefin tuna Thunnus orientalis broodstock in sea cages

We examined the annual reproductive cycle of both female and male hatchery-produced Pacific bluefin tuna (PBT, Thunnus orientalis) broodstock at 3 years of age, including the associated changes in plasma levels of sex steroid hormones and the gene expression of key endocrine factors. The females progressed to vitellogenesis in April, and approximately 50% of the females were observed in late vitellogenesis between June and July at water temperatures between 24.1 °C and 29.0 °C. Approximately 90% of the males were in spermiation for at least 7 months between April and October, which included the period when vitellogenic females were present. Furthermore, the gonadosomatic index of both females and males peaked between June and July. These results indicate that the reproductive season of hatchery-produced PBT peaks between June and July, which is in agreement with the reproductive season reported for PBT broodstock originating from wild-caught juveniles. Furthermore, the percentage of hatchery-reared females that reached late vitellogenesis in the present study was higher than that in wild-caught captive-reared females reported in previous literature. Analysis of plasma sex steroid levels and gene expression profiles suggested that oocyte and ovarian development were associated with 17β-estradiol (E2) control, whereas spermatogonial differentiation towards meiosis seemed to be mediated by 11-ketotestosterone (11-KT). Furthermore, the production of E2 and 11-KT is likely regulated by luteinizing hormone and follicle-stimulating hormone, respectively, via their related receptors. The findings of this study are expected to contribute to improvements of technologies for obtaining fertilized eggs from hatchery-produced PBT broodstock.

Influence of lighting environment on social preferences in sticklebacks from two different photic habitats. I. mate preferences of wild-caught females.

Ultraviolet (UV) A signals (320–400 nm) are important in mate choice in numerous species. The sensitivity for UV signals is not only assumed to be costly, but also expected to be a function of the prevailing ecological conditions. Generally, those signals are favored by selection that efficiently reach the receiver. A decisive factor for color signaling is the lighting environment, especially in aquatic habitats, as the visibility of signals, and thus costs and benefits, are instantaneously influenced by it. Although ecological aspects of color signal evolution are relatively well-studied, there is little data on specific effects of environmental UV-light conditions on signaling at these shorter wavelengths. We studied wild-caught gravid female 3-spined sticklebacks Gasterosteus aculeatus of 2 photic habitat types (tea-stained and clear-water lakes), possessing great variation in their UV transmission. In 2 treatments, tea-stained and clear-water, preferences for males viewed under UV-present (UV+) and UV-absent (UV–) conditions were tested. A preference for males under UV+ conditions was found for females from both habitat types, thus stressing the significance of UV signals in stickleback’s mate choice decisions. However, females from both habitat types showed the most pronounced preferences for males under UV+ conditions under clear-water test conditions. Moreover, reflectance measurements revealed that the carotenoid-based orange-red breeding coloration in wild-caught males of both habitat types differed significantly in color intensity (higher in clear-water males) and hue (more red shifted in clear-water males) while no significant differences in UV coloration were found. The differential reflection patterns in longer wavelengths suggest that sticklebacks of both habitat types have adapted to the respective water conditions. Adaptations of UV signals in a sexual context to ambient light conditions in both behavior and coloration seem less evident.

Fitness characteristics of the malaria vector Anopheles funestus during an attempted laboratory colonization

BackgroundThe malaria vector Anopheles funestus is increasingly recognized as a dominant vector of residual transmission in many African settings. Efforts to better understand its biology and control are significantly impeded by the difficulties of colonizing it under laboratory conditions. To identify key bottlenecks in colonization, this study compared the development and fitness characteristics of wild An. funestus from Tanzania (FUTAZ) and their F1 offspring during colonization attempts. The demography and reproductive success of wild FUTAZ offspring were compared to that of individuals from one of the only An. funestus strains that has been successfully colonized (FUMOZ, from Mozambique) under similar laboratory conditions.MethodsWild An. funestus (FUTAZ) were collected from three Tanzanian villages and maintained inside an insectary at 70–85% RH, 25–27 °C and 12 h:12 h photoperiod. Eggs from these females were used to establish three replicate F1 laboratory generations. Larval development, survival, fecundity, mating success, percentage pupation and wing length were measured in the F1 -FUTAZ offspring and compared with wild FUTAZ and FUMOZ mosquitoes.ResultsWild FUTAZ laid fewer eggs (64.1; 95% CI [63.2, 65.0]) than FUMOZ females (76.1; 95% CI [73.3, 79.1]). Survival of F1-FUTAZ larvae under laboratory conditions was low, with an egg-to-pupae conversion rate of only 5.9% compared to 27.4% in FUMOZ. The median lifespan of F1-FUTAZ females (32 days) and males (33 days) was lower than FUMOZ (52 and 49 for females and males respectively). The proportion of female F1-FUTAZ inseminated under laboratory conditions (9%) was considerably lower than either FUMOZ (72%) or wild-caught FUTAZ females (92%). This resulted in nearly zero viable F2-FUTAZ eggs produced. Wild FUTAZ wings appear to be larger compared to the lab reared F1-FUTAZ and FUMOZ.ConclusionsThis study indicates that poor larval survival, mating success, low fecundity and shorter survival under laboratory conditions all contribute to difficulties in colonizing of An. funestus. Future studies should focus on enhancing these aspects of An. funestus fitness in the laboratory, with the biggest barrier likely to be poor mating.

Conservation genomics reveals low genetic diversity and multiple parentage in the threatened freshwater mussel, Margaritifera hembeli

Margaritifera hembeli is a federally threatened freshwater mussel species restricted to three central Louisiana drainages. Currently, management efforts are being formulated without an understanding of population-level genetic patterns, which could result in sub-optimal conservation outcomes. In particular, information about riverscape genetic patterns is needed to design effective propagation and reintroduction plans. We apply a genomic approach (RADseq) to assess genetic diversity and structure among four wild populations sampled from across the species range. We also assess the genetic diversity of a captively reared cohort produced from a single female. We recovered population differentiation between individuals sampled to the north and south of the Red River. All sites had similarly low levels of heterogeneity and other measures of genetic diversity. The captive cohort displayed higher levels of genetic diversity than expected and likely represents a case of multiple paternity. Future propagation efforts will likely be able to produce genetically diverse cohorts from a small number of wild-caught females, and we recommend future reintroduction efforts utilize brooders within the sub-drainage closest to the reintroduction effort.

An abnormal rostrum in a wild subadult shrimp Farfantepenaeus duorarum (Burkenroad, 1939) (Decapoda, Penaeidae) from the southern Gulf of Mexico

Abstract An abnormal bifid rostrum is reported for the first time for a wild-caught subadult female (carapace length = 22.5 mm) of the pink shrimp Farfantepenaeus duorarum (Burkenroad, 1939) from Celestun lagoon, Yucatan, southern Gulf of Mexico. A review of registers on morphological abnormalities in shrimps of the family Penaeidae is provided.

Structure and Sequence of the Sex Determining Locus in Two Wild Populations of Nile Tilapia.

In domesticated strains of the Nile tilapia, phenotypic sex has been linked to genetic variants on linkage groups 1, 20 and 23. This diversity of sex-loci might reflect a naturally polymorphic sex determination system in Nile tilapia, or it might be an artefact arising from the process of domestication. Here, we searched for sex-determiners in wild populations from Kpandu, Lake Volta (Ghana-West Africa), and from Lake Koka (Ethiopia-East Africa) that have not been subjected to any genetic manipulation. We analysed lab-reared families using double-digest Restriction Associated DNA sequencing (ddRAD) and analysed wild-caught males and females with pooled whole-genome sequencing (WGS). Strong sex-linked signals were found on LG23 in both populations, and sex-linked signals with LG3 were observed in Kpandu samples. WGS uncovered blocks of high sequence coverage, suggesting the presence of B chromosomes. We confirmed the existence of a tandem amh duplication in LG23 in both populations and determined its breakpoints between the oaz1 and dot1l genes. We found two common deletions of ~5 kb in males and confirmed the presence of both amhY and amh∆Y genes. Males from Lake Koka lack both the previously reported 234 bp deletion and the 5 bp frameshift-insertion that creates a premature stop codon in amh∆Y.

Nonlinear maternal effects on personality in a rodent species with fluctuating densities.

Consistent among-individual variation in behavior, or animal personality, is present in a wide variety of species. This behavioral variation is maintained by both genetic and environmental factors. Parental effects are a special case of environmental variation and are expected to evolve in populations experiencing large fluctuations in their environment. They represent a non-genetic pathway by which parents can transmit information to their offspring, by modulating their personality. While it is expected that parental effects contribute to the observed personality variation, this has rarely been studied in wild populations. We used the multimammate mouse Mastomys natalensis as a model system to investigate the potential effects of maternal personality on offspring behavior. We did this by repeatedly recording the behavior of individually housed juveniles which were born and raised in the lab from wild caught females. A linear correlation, between mother and offspring in behavior, would be expected when the personality is only affected by additive genetic variation, while a more complex relationship would suggests the presence of maternal effects. We found that the personality of the mother predicted the behavior of their offspring in a non-linear pattern. Exploration behavior of mother and offspring was positively correlated, but only for slow and average exploring mothers, while this correlation became negative for fast exploring mothers. This may suggests that early maternal effects could affect personality in juvenile M. natalensis, potentially due to density-dependent and negative frequency-dependent mechanisms, and therefore contribute to the maintenance of personality variation.

Effects of essential fatty acids and feeding regimes on egg and offspring quality of European eel: Comparing reproductive success of farm-raised and wild-caught broodstock

Production of high-quality offspring from farm-raised broodstock is fundamental to establish a closed-cycle hatchery production of European eel, Anguilla anguilla. While development of larval culture technologies progresses, the present study focused on effects of essential fatty acid (EFA) composition of eggs on offspring quality. Three reproduction experiments were conducted, two of which included farm-raised broodstock fed different diets for different periods of time and one wild-caught broodstock, using size-matched females. The formulated diets varied in levels and ratios of three essential fatty acids, arachidonic acid (20:4n-6; ARA), eicosapentaenoic acid (20:5n-3; EPA), and docosahexaenoic acid (22:6n-3; DHA), while feeding periods lasted either 55 or 79 weeks. Dietary influences on egg and offspring fatty acid composition and offspring quality were evaluated and results of the most successful dietary regime was compared to those of wild-caught females. Results showed that elevated dietary levels of ARA were reflected in unfertilized eggs, with high ARA diets significantly increasing the amounts of floating eggs, total lipid content in eggs, fertilization success, and embryonic survival. Further EFA enhancements and prolonged feeding resulted in higher ARA and lower EPA levels in the unfertilized eggs, while DHA levels did not change. Females with prolonged feeding produced offspring of higher quality, i.e. higher egg dry weight and larval survival. Overall, offspring of farm-raised females showed higher EFA levels than those of wild-caught females. However, while fertilization success was comparable, offspring of farm-raised females had significantly lower embryonic survival and hatch success as well as higher proportions of cleavage abnormalities. These results identified embryonic development as the main bottleneck in offspring production from farm-raised females. Once hatched, larval survival and quality was comparable between farm-raised and wild-caught females. Notably, enhancement of essential fatty acids in female broodstock diets in combination with a long feeding period improved the production of high quality offspring.

Restored river habitat provides a natural spawning area for a critically endangered landlocked Atlantic salmon population.

Supplementing endangered fish populations with captive bred individuals is a common practice in conservation management. The aim of supplementary releases from hatchery broodstocks is to maintain the viability of populations by maintaining their genetic diversity. Landlocked Lake Saimaa salmon (Salmo salar m. sebago) has been critically endangered for the past half-century. As a result of anthropogenic disturbance, especially construction of hydroelectric power plants, the Lake Saimaa salmon has become completely dependent on hatchery broodstock. Recently, habitat restoration has been done in one of the former spawning rivers with the aim of creating a new natural spawning ground for the critically endangered population. Hatchery fish releases have also been revised so that in addition to juveniles, adult fish from the hatchery and from the wild have been released into the restored river. We assessed here if a restored river stretch can be used as a natural spawning ground and juvenile production area with the aim of improving genetic diversity of the critically endangered Lake Saimaa salmon. By constructing a pedigree of the released adults, and juveniles sampled from the restored river, we found that the majority of the released adults had produced offspring in the river. We also found that wild-caught spawners that were released into the restored river had much higher reproductive success than hatchery-reared parents that were released into the restored river at the same time. We found no significant differences in genetic diversity between the parent and offspring generations. Meanwhile, relatedness among different groups of adults and juveniles varied a lot. For example, while the hatchery-reared females were on average half-siblings, wild-caught females showed no significant relatedness. This highlights the importance of using pedigree information in planning the conservation and management of endangered populations, especially when artificial propagation is involved.