Poecilia Latipinna Research Articles

Prevalence of Centrocestus formosanus Metacercariae in Ornamental Fish from Chiang Mai, Thailand, with Molecular Approach Using ITS2.

The prevalence of Centrocestus formosanus metacercariae was investigated in ornamental fish purchased from a pet shop in Chiang Mai, Thailand, including Carassius auratus (goldfish), Cyprinus carpio (Koi), Poecilia latipinna (Sailfin Molly), Danio rerio (Zebrafish), and Puntigrus tetrazona (Tiger barb). The parasite species was identified by the morphology of worms as well as by a molecular approach using ITS2. The results showed that 50 (33.3%) of 150 fish examined were infected with the metacercariae. The highest prevalence was found in C. auratus (83.3%), and the highest intensity was noted in C. carpio (70.8 metacercariae/fish). The most important morphological character was the presence of 32–34 circumoral spines on the oral sucker. The phylogenetic studies using the rRNA ITS2 region revealed that all the specimens of C. formosanus in this study were grouped together with C. formosanus in GenBank database. This is the first report on ornamental fish, C. carpio, P. latipinna, D. rerio, and P. tetrazona, taking the role of second intermediate hosts of C. formosanus in Thailand. Prevention and control of metacercarial infection in ornamental fish is urgently needed.

Avoidance of oil contaminated sediments by estuarine fishes

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 576:125-134 (2017) - DOI: https://doi.org/10.3354/meps12084 Theme Section: Response of nearshore ecosystems to the Deepwater Horizon oil spill Avoidance of oil contaminated sediments by estuarine fishes Charles W. Martin* Department of Oceanography Coastal Sciences, Louisiana State University, Baton Rouge, LA 70803, USA Present address: University of Florida Institute of Food and Agricultural Sciences Nature Coast Biological Station, Cedar Key, FL 32625, USA *Corresponding author: martin.charles.w@gmail.comAdvance View was available online March 8, 2017; subsequently updated May 2, 2017 ABSTRACT: The explosion of the Deepwater Horizon drilling platform and subsequent discharge of hydrocarbons into the Gulf of Mexico is the largest oil spill that has affected US waters. To date, studies of ecological effects on coastal fishes have produced complex results. While laboratory studies indicate that oil has widespread, pervasive impacts on fish physiology, field assessments often document few impacts to fish abundance and biomass following a spill. The dichotomy of such results suggests that negative individual-level effects do not translate to population/community-level consequences. One explanation for this discrepancy is that mobile organisms may avoid oil, which was very patchily distributed. Here, I present the results of experiments using 3 estuarine fishes (gulf killifish Fundulus grandis, sailfin molly Poecilia latipinna, and sheepshead minnow Cyprinodon variegatus) to determine whether behavioral avoidance occurs at a range of concentrations (0, 10, 20, and 40 ml oil l-1 of sediment) and weathering (fresh or weathered oil) scenarios. All 3 species avoided medium (35, 18, 10% of trial time, respectively) and high concentrations of fresh oil (30, 20, and 15%, respectively), while time spent over contaminated sediments at low concentrations of fresh oil was higher (30, 40, and 40%, respectively). Weathered crude elicited no significant avoidance behavior, with fish occupying between 40 and 60% of the trial period over these sediments, regardless of concentration. This research highlights the heretofore unrecognized role of behavior in fish resilience, as well as the need for future studies to incorporate ecologically relevant weathering rates. Such results are critical to the successful management of motile resources, such as estuarine fishes, in response to anthropogenic disasters such as oil spills. KEY WORDS: Salt marsh · Gulf of Mexico · Fish ecology · Experiment · Avoidance behavior · Oil contamination · Oil spill · Deepwater Horizon · Macondo Full text in pdf format PreviousNextCite this article as: Martin CW (2017) Avoidance of oil contaminated sediments by estuarine fishes. Mar Ecol Prog Ser 576:125-134. https://doi.org/10.3354/meps12084 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 576. Online publication date: August 03, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

Temporal Expression Pattern of Peptides in the Regenerating Caudal Fin of Teleost Fish Poecilia latipinna With Special Emphasis on krt15 and myl-1

Amongst several vertebrates, caudal fin of teleost fish has been emerged as an excellent model to understand the mechanism of regeneration. By now it is well perceived that proper coordination of different regulatory signals are needed to facilitate the progression of successive stages of regeneration. Therefore, in the current study protein expression profile for caudal fin regeneration in Poecilia latipnna was brought into the focus. The pattern of protein turnover and variation in the expression level were observed across the stages of regeneration. Data from twodimensional gel electrophoresis revealed the differential expression of proteins for wound epithelium, blastema and differentiation stages when compared to resting stage. Based on the computational analysis, of the peptide expression profile and subsequent sequencing, two peptides namely Keratin type I cytoskeletal 15 and Myosin light chain-1 were studied further at transcript level. keratin-15 was found to be up regulated at wound epithelium stage while its expression waned significantly in the blastema and differentiation stages of regeneration indicating its role in the formation of a functional wound epithelium. Western blot analysis of keratin-15 also concurred with transcript levels of krt15. However, myl-1 transcript levels was observed to be dispensable for initial phase of regeneration whereas its elevated level in differentiation stage at both mRNA and protein level marks its noteworthy role in achieving the structural integrity of a regenerating caudal fin. This is the first observation of the involvement of keratin-15 and Myosin light chain-1 in the regulation of regenerative process in Poecilia latipinna.

Differential sensitivity to estrogen-induced opsin expression in two poeciliid freshwater fish species

The sensory system shapes an individual’s perception of the world, including social interactions with conspecifics, habitat selection, predator detection, and foraging behavior. Sensory signaling can be modulated by steroid hormones, making these processes particularly vulnerable to environmental perturbations. Here we examine the influence of exogenous estrogen manipulation on the visual physiology of female western mosquitofish (Gambusia affinis) and sailfin mollies (Poecilia latipinna), two poeciliid species that inhabit freshwater environments across the southern United States. We conducted two experiments to address this aim. First, we exposed females from both species to a one-week dose response experiment with three treatments of waterborne β-estradiol. Next, we conducted a one-week estrogen manipulation experiment with a waterborne estrogen (β-Estradiol), a selective estrogen receptor modulator (tamoxifen), or combination estrogen and tamoxifen treatment. We used quantitative PCR (qPCR) to examine the expression of cone opsins (SWS1, SWS2b, SWS2a, Rh2, LWS), rhodopsin (Rh1), and steroid receptor genes (ARα, ARβ, ERα, ERβ2, GPER) in the eyes of individual females from each species. Results from the dose response experiment revealed estradiol-sensitivity in opsin (SWS2a, Rh2, Rh1) and androgen receptor (ARα, ARβ) gene expression in mosquitofish females, but not sailfins. Meanwhile, our estrogen receptor modulation experiments revealed estrogen sensitivity in LWS opsin expression in both species, along with sensitivity in SWS1, SWS2b, and Rh2 opsins in mosquitofish. Comparisons of control females across experiments reveal species-level differences in opsin expression, with mosquitofish retinas dominated by short-wavelength sensitive opsins (SWS2b) and sailfins retinas dominated by medium- and long-wavelength sensitive opsins (Rh2 and LWS). Our research suggests that variation in exogenous levels of sex hormones within freshwater environments can modify the visual physiology of fishes in a species-specific manner.

The virtual lover: variable and easily guided 3D fish animations as an innovative tool in mate-choice experiments with sailfin mollies-I. Design and implementation.

Animal behavior researchers often face problems regarding standardization and reproducibility of their experiments. This has led to the partial substitution of live animals with artificial virtual stimuli. In addition to standardization and reproducibility, virtual stimuli open new options for researchers since they are easily changeable in morphology and appearance, and their behavior can be defined. In this article, a novel toolchain to conduct behavior experiments with fish is presented by a case study in sailfin mollies Poecilia latipinna. As the toolchain holds many different and novel features, it offers new possibilities for studies in behavioral animal research and promotes the standardization of experiments. The presented method includes options to design, animate, and present virtual stimuli to live fish. The designing tool offers an easy and user-friendly way to define size, coloration, and morphology of stimuli and moreover it is able to configure virtual stimuli randomly without any user influence. Furthermore, the toolchain brings a novel method to animate stimuli in a semiautomatic way with the help of a game controller. These created swimming paths can be applied to different stimuli in real time. A presentation tool combines models and swimming paths regarding formerly defined playlists, and presents the stimuli onto 2 screens. Experiments with live sailfin mollies validated the usage of the created virtual 3D fish models in mate-choice experiments.

The virtual lover: variable and easily guided 3D fish animations as an innovative tool in mate-choice experiments with sailfin mollies-II. Validation.

The use of computer animation in behavioral research is a state-of-the-art method for designing and presenting animated animals to live test animals. The major advantages of computer animations are: (1) the creation of animated animal stimuli with high variability of morphology and even behavior; (2) animated stimuli provide highly standardized, controlled and repeatable testing procedures; and (3) they allow a reduction in the number of live test animals regarding the 3Rs principle. But the use of animated animals should be attended by a thorough validation for each test species to verify that behavior measured with live animals toward virtual animals can also be expected with natural stimuli. Here we present results on the validation of a custom-made simulation for animated 3D sailfin mollies Poecilia latipinna and show that responses of live test females were as strong to an animated fish as to a video or a live male fish. Movement of an animated stimulus was important but female response was stronger toward a swimming 3D fish stimulus than to a “swimming” box. Moreover, male test fish were able to discriminate between animated male and female stimuli; hence, rendering the animated 3D fish a useful tool in mate-choice experiments with sailfin mollies.

Effects of macrophyte-specific olfactory cues on fish preference patterns

Vegetated habitats provide numerous benefits to nekton, including structural refuge from predators and food sources. However, the sensory mechanisms by which fishes locate these habitats remain unclear for many species, especially when environmental conditions (such as increased turbidity) are unfavorable for visual identification of habitats. Here, a series of laboratory experiments test whether three species of adult fish (golden topminnow Fundulus chrysotus Gunther 1866, sailfin molly Poecilia latipinna Lesueur 1821, and western mosquitofish Gambusia affinis Baird and Girard 1853) use plant chemical cues to orient to one of two habitats [hydrilla Hydrilla verticillata (L.f.) Royle or water hyacinth Eichhornia crassipes (Mart.) Solms]. First, experiments in aquaria were conducted offering fish a choice of the two habitats to determine preference patterns. Next, a two-channel flume, with each side containing flow originating in one of the two habitats, was used to determine whether preferences were still exhibited when fish could only detect habitats through olfactory means. While patterns among the three fish species tested here were variable, results did indicate consistent habitat preferences despite the lack of cues other than olfactory, suggesting that these organisms are capable of discriminating habitats via chemical exudates from plants. As such, olfactory mechanisms likely provide vital information about the surrounding environment and future work should be directed at determining how anthropogenic inputs such as eutrophication and sediment runoff affect the physiology of these sensory capabilities.

Assays to Detect UV-reflecting Structures and Determine their Importance in Mate Preference using the Sailfin Molly <em>Poecilia latipinna</em>

Many organisms use cues and signals beyond human sensitivity during social interactions. It is important to take into account how organisms perceive their worlds when trying to understand their behavior and ecology. Sensitivity to the ultraviolet spectrum (UV; 300 - 400 nm) is found across multiple genera of birds, fish, reptiles, amphibians, and even mammals. This protocol describes a technique for examining organisms for the presence of UV-reflecting structures and a method for testing whether these cues are used as social signals in the context of mate choice. A spectrophotometer is used to detect the presence of UV reflectance and variation in reflective intensity between individuals and sexes. An example of this technique is presented in which a dichotomous mate choice test exposes sexually receptive individuals to opposite sex individuals whose visual appearance can be manipulated by filters that either transmit full spectrum or block UV wavelengths. This system allowed for the determination that female, but not male, sailfin mollies (Poecilia latipinna) were using UV markings as part of their mating decisions. These types of studies serve to expand our knowledge of the range of organisms that utilize UV and provide insight into how UV plays a role in their lives.

Assays to Detect UV-reflecting Structures and Determine their Importance in Mate Preference using the Sailfin Molly Poecilia latipinna.

Many organisms use cues and signals beyond human sensitivity during social interactions. It is important to take into account how organisms perceive their worlds when trying to understand their behavior and ecology. Sensitivity to the ultraviolet spectrum (UV; 300 - 400 nm) is found across multiple genera of birds, fish, reptiles, amphibians, and even mammals. This protocol describes a technique for examining organisms for the presence of UV-reflecting structures and a method for testing whether these cues are used as social signals in the context of mate choice. A spectrophotometer is used to detect the presence of UV reflectance and variation in reflective intensity between individuals and sexes. An example of this technique is presented in which a dichotomous mate choice test exposes sexually receptive individuals to opposite sex individuals whose visual appearance can be manipulated by filters that either transmit full spectrum or block UV wavelengths. This system allowed for the determination that female, but not male, sailfin mollies (Poecilia latipinna) were using UV markings as part of their mating decisions. These types of studies serve to expand our knowledge of the range of organisms that utilize UV and provide insight into how UV plays a role in their lives.

Social environment affects female preference for male body color during development in artificially selected varieties of Poecilia latipinna

This study provides evidence for an effect of social environment on color morph preference during development in two artificially selected varieties of the live-bearing fish Poecilia latipinna. Black-colored females reared exclusively in the presence of white-colored adults preferred to associate with white vs black males when tested using a standard dichotomous choice design. Similarly, white females reared exclusively in the presence of black adults showed a preference for black males in identical dichotomous choice tests. However, both black and white females when reared separately in the presence of a mix of black and white adults showed no preference for either male color variety. A second round of testing revealed that their preferences (or lack thereof), although significantly weaker, persisted for at least a week after the initial tests during which the model groups were altered; groups reared in the presence of opposite-colored adults were exposed to mixed-color adults, while groups reared in the presence of mixed-color adults were exposed to opposite-color models. Taken together, these data indicate that the females’ social environment during the first 2 months of life affected the development of preferences for male body color and further suggest such social learning could potentially influence mate and/or shoaling preferences for color and perhaps other traits in natural populations of P. latipinna.

Sequence Evolution and Expression of the Androgen Receptor and Other Pathway-Related Genes in a Unisexual Fish, the Amazon Molly, Poecilia formosa, and Its Bisexual Ancestors.

The all-female Amazon molly (Poecilia formosa) originated from a single hybridization of two bisexual ancestors, Atlantic molly (Poecilia mexicana) and sailfin molly (Poecilia latipinna). As a gynogenetic species, the Amazon molly needs to copulate with a heterospecific male, but the genetic information of the sperm-donor does not contribute to the next generation, as the sperm only acts as the trigger for the diploid eggs’ embryogenesis. Here, we study the sequence evolution and gene expression of the duplicated genes coding for androgen receptors (ars) and other pathway-related genes, i.e., the estrogen receptors (ers) and cytochrome P450, family19, subfamily A, aromatase genes (cyp19as), in the Amazon molly, in comparison to its bisexual ancestors. Mollies possess–as most other teleost fish—two copies of the ar, er, and cyp19a genes, i.e., arα/arβ, erα/erβ1, and cyp19a1 (also referred as cyp19a1a)/cyp19a2 (also referred to as cyp19a1b), respectively. Non-synonymous single nucleotide polymorphisms (SNPs) among the ancestral bisexual species were generally predicted not to alter protein function. Some derived substitutions in the P. mexicana and one in P. formosa are predicted to impact protein function. We also describe the gene expression pattern of the ars and pathway-related genes in various tissues (i.e., brain, gill, and ovary) and provide SNP markers for allele specific expression research. As a general tendency, the levels of gene expression were lowest in gill and highest in ovarian tissues, while expression levels in the brain were intermediate in most cases. Expression levels in P. formosa were conserved where expression did not differ between the two bisexual ancestors. In those cases where gene expression levels significantly differed between the bisexual species, P. formosa expression was always comparable to the higher expression level among the two ancestors. Interestingly, erβ1 was expressed neither in brain nor in gill in the analyzed three molly species, which implies a more important role of erα in the estradiol synthesis pathway in these tissues. Furthermore, our data suggest that interactions of steroid-signaling pathway genes differ across tissues, in particular the interactions of ars and cyp19as.

Trade-offs between salinity preference and antipredator behaviour in the euryhaline sailfin molly Poecilia latipinna.

Salinity preference and responses to predatory chemical cues were examined both separately and simultaneously in freshwater (FW) and saltwater (SW)-acclimated sailfin mollies Poecilia latipinna, a euryhaline species. It was hypothesized that P. latipinna would prefer FW over SW, move away from chemical cues from a crayfish predator, and favour predator avoidance over osmoregulation when presented with both demands. Both FW and SW-acclimated P. latipinna preferred FW and actively avoided predator cues. When presented with FW plus predator cues v. SW with no cues, P. latipinna were more often found in FW plus predator cues. These results raise questions pertaining to the potential osmoregulatory stress of salinity transitions in euryhaline fishes relative to the potential fitness benefits and whether euryhalinity is utilized for predator avoidance. This study sheds light on the potential benefits and consequences of being salt tolerant or intolerant and complicates the understanding of the selection pressures that have favoured the different osmoregulatory mechanisms among fishes.

Development of Cost Effective Nutritionally Balanced Food for Freshwater Ornamental Fish Black Molly (Poecilia latipinna)

Fishery is one of the oldest professions of man and even today, it helps in food security and poverty alleviation, in many parts of the world. Fish culturing is major part of aquaculture. When natural fishery does not suffice the need of the society, world has gone for aquaculture to increase the productivity. On the same lines, in ornamental fishery too, man’s interference in deciding the breed, formulating the feed, bringing changes in living conditions of the fishes, etc., is very much in vogue. To improve the health of the fishes, and their productivity of ornamental fisheries, nutrition plays a major role. In this direction, several attempts have been made by various workers, to alter the food and other environmental conditions. However, as there are hardly any attempt to develop low cost balanced food for ornamental fishes, present paper deals with formulating low cost nutritionally balanced food for Black Molly (Poecilia latipinna), a popular freshwater ornamental fishes has been attempted, by using locally available `waste material’ like Groundnut oil cake, Fish meal, Wheat bran, Snail, Marine Fish waste, Freshwater Fish waste, Chicken waste, Earthworms, Squids, Mussel, Chicken liver, Prawn meal, etc., The results obtained on growth and nutrition utilization indicated by weight gain and specific growth rate of Black Molly was highest, in fish fed with diet containing Snail meal, Prawn meal, Mussel meal and Chicken liver. The studies indicate that, these ornamental fishes can be reared well with animal based products, replacing agro based products, which can replace high cost commercial Fish meal

Cognitive evidence of fish sentience

Cognitive evidence of fish sentience

Inhibition of BMP signaling reduces MMP-2 and MMP-9 expression and obstructs wound healing in regenerating fin of teleost fish Poecilia latipinna.

The tail fin of teleost fish responds to amputation by expressing few putative factors that promote scar-free wound healing, which paves the way for restoration of the lost part. Among the factors playing a role in this initial response, bone morphogenetic proteins (BMPs) are crucial. In the current study, we have analyzed the effect of BMP inhibition on wound healing in sailfin molly Poecilia latipinna. The study involved histological assessment of wound epithelium formation, an expression profile of proteins, and gelatinase activity as well as expression in response to BMP signal inhibition. LDN193189, a pharmacological inhibitor of BMP receptor, was administered to experimental fish. Our observations include incomplete wound healing and a significant reduction in the expression of a number of proteins as a result of LDN treatment at 24 h post-amputation. A pronounced effect was also seen on the gelatinases MMP-9 and MMP-2, which showed significantly reduced activities on a zymogram. Reduced expression of these MMPs after inhibitor treatment was also confirmed by western blot and real-time PCR analyses. In view of these results, we confirm that BMP signaling has a definitive role in the early stages of fin regeneration in P. latipinna. The effect of BMP inhibition is especially seen on the expression of MMP-9 and MMP-2, which are very important effectors of tissue remodeling immediately following amputation.

Prevalence and Histopathologic Study of Lernaea cyprinacea in Two Species of Ornamental Fish (Poecilia latipinna and Xiphophorus helleri) in Kerman, South-East Iran.

Lernaeids are crustacean parasites that are globally distributed among freshwater and marine fish. Approximately 110 species of Lernaeids have been divided into 14 genera. The most common species of Lernaeids is Lernaea cyprinacea, which has been transmitted to ornamental fish worldwide. The economic importance of L. cyprinacea is increasing because of the epidemic caused by the parasite in most of the ornamental fish breeding centers in different parts of the world. The parasite affects its host's health, decreases growth rate, and causes abnormal metabolic activity. Accumulation of these parasites in some parts of the body causes painful points and has harmful outcomes for the functioning and survival of the host. The present study was conducted to examine the prevalence of L. cyprinacea among ornamental fish within 1 year from September-October 2011 to September-October 2012. In total, 3520 fish [3380 mollies (Poecilia latipinna) and 140 swordtails (Xiphophorus helleri)] were collected from 10 fish maintenance and breeding centers in Kerman, Iran. Of 3520 fish, only 186 fish (5.3%) were infected with L. cyprinacea, and the remaining fish (94.7%) were not infected. The swordtails (X. helleri) and mollies (P. latipinna) showed the highest (10.7%) and the lowest (5.1%) level of infection, respectively. In other words, there was a significant correlation between species of fish and L. cyprinacea infection (p<0.05). The highest prevalence (39.4%) and the lowest prevalence (0%) of L. cyprinacea were observed during summer and winter, respectively, which can be attributed to the temperature difference between the two seasons. Also, the histopathologic examination of sections revealed some lesions in the epidermis, dermis, and muscles. Considering the existing L. cyprinacea infection in ornamental fish reproduction and breeding centers in Kerman, public knowledge should increase through management methods; physical and chemical treatments should also be applied to inform the public regarding the risk of infection and other internal diseases that may be associated with ornamental fish.

Population Genomics of the Euryhaline Teleost Poecilia latipinna.

Global climate change and increases in sea levels will affect coastal marine communities. The conservation of these ecologically important areas will be a challenge because of their wide geographic distribution, ecological diversity and species richness. To address this problem, we need to better understand how the genetic variation of the species in these communities is distributed within local populations, among populations and between distant regions. In this study we apply genotyping by sequencing (GBS) and examine 955 SNPs to determine Sailfin molly (Poecilia latipinna) genetic diversity among three geographically close mangrove salt marsh flats in the Florida Keys compared to populations in southern and northern Florida. The questions we are asking are whether there is sufficient genetic variation among isolated estuarine fish within populations and whether there are significant divergences among populations. Additionally, we want to know if GBS approaches agree with previous studies using more traditional molecular approaches. We are able to identify large genetic diversity within each saltmarsh community (π ≈ 36%). Additionally, among the Florida Key populations and the mainland or between southern and northern Florida regions, there are significant differences in allele frequencies seen in population structure and evolutionary relationships among individuals. Surprisingly, even though the cumulative FST value using all 955 SNPs within the three Florida Key populations is small, there are 29 loci with significant FST values, and 11 of these were outliers suggestive of adaptive divergence. These data suggest that among the salt marsh flats surveyed here, there is significant genetic diversity within each population and small but significant differences among populations. Much of the genetic variation within and among populations found here with GBS is very similar to previous studies using allozymes and microsatellites. However, the meaningful difference between GBS and these previous measures of genetic diversity is the number of loci examined, which allows more precise delineations of population structure as well as facilitates identifying loci with excessive FST values that could indicate adaptive divergence.

Pre-existing biases for swords in mollies (Poecilia)

Pre-existing female biases are female preferences for a particular trait that evolved prior to the evolution of that trait. Phylogenies are needed to show when the preference and trait have originated. In several live-bearing fishes (Poeciliidae), females show pre-existing biases for male swords, a colorful extension of the caudal fin. Here, we investigated the pre-existing bias hypothesis by predicting preferences for a sword in several molly species, including 2 unusual species in the monophyletic subclade Mollienesia: the Amazon molly, Poecilia formosa, a sperm-dependent hybrid form, and the Tamesi molly, Poecilia latipunctata, a species in the long-fin molly clade, that has a short-fin morphology. Using published sequence data available for this family, behavioral approaches, robust phylogenetic analyses, and Bayesian ancestral state reconstructions, we tested whether the hybrid P. formosa has a preference similar to the maternal ancestor, Poecilia mexicana, or the paternal ancestor, Poecilia latipinna. Surprisingly, the preference shown by P. formosa was variable between populations and matched the preference found in the co-occurring host species. In P. latipunctata, we found a pre-existing bias for sworded males, suggesting that this represents an ancestral trait for the long-fin molly clade. On the basis of the combined evidence from multiple studies, it seems as if pre-existing biases for sworded males are relatively basal to poeciliids and that existing phylogenetic relationships allow us to predict sensory biases.

Effects of Female‐Female Aggression in a Sexual/Unisexual Species Complex

AbstractThe maintenance of sexual reproduction is still a largely unresolved question in evolutionary biology, and one of the most puzzling aspects of this is the coexistence of sexual and asexual females. This often leads to widespread niche overlap, posing an interesting challenge to competitive exclusion theory. In this study, we investigate how the aggressive behaviors between females in a sexual/unisexual mating complex of mollies (Poecilia latipinna and P. formosa) differ, and the effects these behaviors have on both the performer and receiver of aggressive acts. We exposed females to five treatments: (1) alone (control); (2) a large and small sexual female; (3) a large sexual female and a small unisexual female; (4) a small sexual female and a large unisexual female; and (5) a large and small unisexual female. We found that P. formosa females were on average more aggressive over time when compared to their sexual hosts, P. latipinna. The females of P. formosa, however, incurred a higher cost of being aggressive. Large, aggressor females of this species had a lower body fat content than their conspecific recipients. By contrast, P. latipinna females showed no differentiation between aggressors and recipients. Here, we combine life history methodology and behavioral observations to show that female competition can in fact be quantitatively measured and that these aggressive behaviors are costly to perform. The adaptive value of this interspecies aggression is not yet completely understood, but sexual competition, access to resources, and position within the shoal are all possible functions.

Evaluating the Effects of Urban Land Use on the Condition of Resident Salt Marsh Fish

Urbanization can impact coastal fisheries by reducing the quality of important habitats, including salt marshes. Similarly, increased urban land use surrounding tidal creeks can impact the health of fish by changing salinities, altering habitat structure, and increasing exposure to pollution. In this study, we investigated the effects of residential urban land use on the condition of salt marsh resident fish along the northern Gulf of Mexico. Fish were sampled seasonally using minnow traps along salt marshes near the mouth of six second-order tidal creeks (three surrounded by residential development and three surrounded primarily by forest) in Alabama and west Florida. Fundulus grandis and Poecilia latipinna were the dominant species representing 65 % (n = 3588) and 15 % (n = 777) of the total number of fish caught, respectively. All F. grandis and P. latipinna were evaluated for mass, length, and length-weight relationship. A subset (745 and 367, respectively) was further analyzed for conditional measures of caloric density and liver somatic index (LSI). The mass per length relationships did not differ between urban and reference creeks for either F. grandis or P. latipinna; however, reference creeks yielded F. grandis and P. latipinna that were significantly larger. Further, F. grandis and P. latipinna had significantly lower LSI and caloric density in urban creeks compared to reference. Both species showed seasonal patterns of conditional measures that were likely related to reproduction and annual fattening cycles. Differences in fish condition between urban and reference creeks may reflect differences in food availability/quality, creek salinity regimes, and salt marsh structure.