Female Parasites Research Articles

The use of fish parasitic isopods as element accumulation indicators in marine pollution monitoring

Marine ecosystems are continuously under threat due to pollutants, which endanger marine biodiversity. The present study determines the potential use of the parasitic isopod, Cinusa tetrodontis Schjödte et Meinert, 1884, together with its fish host, Amblyrhynchotes honckenii (Bloch) for marine bioaccumulation monitoring. The concentrations of As, Cd, Cu, Mn, Ni, Pb, Se, and Zn were determined in muscle and liver tissues of infested and uninfested fish, and male and female parasites on the South African temperate south coast. The concentrations of Cu and Ni in C. tetrodontis differed significantly between two sampling sites, a near-pristine (Breede River Estuary, Witsand) and a more polluted site (harbour area in Mossel Bay). Mossel Bay isopods had higher concentrations of Ni, while Witsand isopods had higher concentrations of Cu. In contrast to fish hosts, parasitic isopods accumulated significantly higher levels of all elements except Cd. Most significant relationships between elements accumulated by C. tetrodontis and an increase of elements in fish tissues were seen in liver, rather than muscle tissue samples. Specimens of C. tetrodontis can be defined as good bioindicators for elements such as As, Cu, Mn, Ni, Pb, Se, and Zn, as they possess high bioaccumulation capabilities. This study addresses one of several future directions needed within environmental parasitology and highlights the importance of studying and utilising this host-ectoparasite model system.

Proliferative strongyloidiasis in a colony of colubrid snakes.

Strongyloides are small rhabditid nematodes primarily associated with enteric disease in a variety of animal species, including reptiles. Strongyloides spp life stages were associated with a disease outbreak in a large breeding colony of snakes. Multiple Pantherophis and Lampropeltis colubrids exhibited respiratory distress, anorexia, stomatitis, facial deformation, and waning body condition that resulted in death or necessitated euthanasia. Postmortem examinations of 13 snakes revealed epithelial hyperplasia and inflammation of the alimentary and respiratory tracts associated with varying numbers of adult and larval nematodes and embryonated or larvated ova. In a subset of snakes, aberrant nematode migration was also observed in the eye, genitourinary system, coelom, and vasculature. Histomorphology and gross examination of parasitic adult female nematodes from host tissues were consistent with a Strongyloides spp. Sedimented fecal material from 101/160 (63%) snakes housed in the affected facility was positive for nematodes and/or larvated ova. Polymerase chain reaction amplification and sequencing of portions of the 18S and 28S ribosomal ribonucleic acid (RNA) genes and the internal transcribed spacer region of adult female parasites and positive fecal samples supported the diagnosis of strongyloidiasis. Strongyloides spp possess a unique life cycle capable of alternating between parasitic (homogonic) and free-living (heterogonic) stages, resulting in the production of directly infective larvae. Commonly utilized husbandry practices in reptile collections can amplify the numbers of infective larvae generated in the captive environment, increasing the risk for rhabditid hyperinfections. This report documents morbidity, mortality, and non-enteric disease manifestations due to Strongyloides hyperinfections in a captive colubrid snake colony.

Multiparasitism and repeated parasitism by the great spotted cuckoo Clamator glandarius on its main host, the magpie Pica pica: effects on reproductive success, nest desertion and nest predation

Brood parasites are expected to lay only one egg per parasitized nest, as the existence of several parasitic nestlings in a brood increases competition and can lead the starvation of some of them. However, multiparasitism (laying of two or more eggs by one or more parasitic females in a single host nest) is surprisingly frequent. Here, we study multiparasitism by different females or by the same female (repeated parasitism) in the great spotted cuckoo Clamator glandarius, a non‐evictor brood parasite that mainly parasitizes the magpie Pica pica, and whose chicks may be raised together with host nestlings in the same nest. We used a total of 262 magpie nests found during four breeding seasons. Multiparasitism and repeated parasitism are very frequent because this brood parasite is less virulent than other cuckoo species and magpie hosts can successfully raise more than one parasitic nestling per nest. The total number of cuckoo chicks fledged was higher in multiparasitized nests than in single‐ or double‐parasitized magpie nests. Magpie breeding success (i.e. the proportion of eggs that produce young that leave the nest) did not differ between single‐, double‐, and multiparasitized magpie nests. These results suggest that multiparasitism is an adaptation in the great spotted cuckoo. The intensity of parasitism (number of cuckoo eggs per nest), after controlling for the potential effect of year, did not affect nest desertion or nest predation rate, neither during the incubation nor the nestling periods. This implies that nest concealment does not affect the susceptibility of one nest being parasitized and predated, as nest predation rate was similar regardless of the intensity of parasitism. Predation rate during the nestling phase did not vary according to intensity of parasitism, which does not support either the ‘mutualism' hypothesis or the ‘predation cost of begging' hypothesis.

Route of dexamethasone administration influences parasite burden in Strongyloides hyperinfection model.

Rodents infected with Strongyloides venezuelensis are experimental models applied to strongyloidiasis research. This study evaluated oral and subcutaneous dexamethasone (DEX) treatments to establish immunosuppression in an experimental model of Strongyloides hyperinfection. Rattus norvegicus Wistar were divided: G I (-): untreated and uninfected animals, G II (+): untreated and infected, G III (o -) orally treated and uninfected, G IV (o +) orally treated and infected, G V (sc -) subcutaneously treated and uninfected, G VI (sc +) subcutaneously treated and infected. For oral administration, DEX was diluted in sterile water (5µg/ml) and made available to the animals on intervals in experimental days - 5-0, 8-13 and 21-26. For subcutaneous administration, animals received daily injections of DEX disodium phosphate (2mg/kg). Infection was established by the subcutaneous inoculation of 3000 S. venezuelensis filarioid larvae. Groups were evaluated by egg per gram of feces and parasite females counts and IgG, IgG1 and IgG2a detection. GIV (o +) had egg peaks count on days 13 and 26 and maintained egg elimination until the last experimental day. Parasitic females recovery at day 30 was significantly higher in G IV (o +) when compared to G VI (sc +). Levels of IgG, IgG1 and IgG2a of all groups, except the positive control GII (+), were below the detection threshold. Pharmacological immunosuppression induced by oral administration of DEX produced high parasitic burden, and is a noninvasive method, useful to establish immunosuppression in strongyloidiasis hyperinfection model in rats.

The perks of being in good conditions: How does female parasitism affect male mate choice in an orb‐web spider?

AbstractIt is assumed that males increase their reproductive performance by mating with the highest number of females. However, in some species males are reproductively constrained, being able to mate only a few times. In these cases, it is expected that males choose the highest quality females available. One factor that can change female quality is parasitism, however, many empirical studies fail to find conclusive support for a non‐parasitized female preference. This might be due to the fact that behavioral tests in many studies are made in a controlled environment or use indirect measures of mate choice. Using a natural‐environment approach, we tested whether the mate choice of the golden orb‐web spiderTrichonephila clavipesmale is affected by the presence of the parasite in the female. We hypothesize that males will prefer to establish on webs of non‐parasitized females and will attempt to mate and copulate more with non‐parasitized females over parasitized ones. For this, we conducted field observations for 76 h. We found that males prefer to establish on non‐parasitized female webs than on parasitized ones. However, there was no difference between the number of attempts to mate and copulations of parasitized and non‐parasitized females. It seems that males can distinguish between parasitized and non‐parasitized females, but once they establish on a female web, they are resistant to leave. One possible explanation is that some males stay on a parasitized female web to avoid competition with other males. Therefore, it is possible that mating with parasitized females represents a “making the best of a bad job” mating tactic inT. clavipes.

Studies on the Efficacy of Heterogeneously Produced Pasteuria Penetrans (PP3) Isolate over Individual Pasteuria Isolates in the Spore Attachment, and Pathogenic Potential on Three Meloidogyne Species

The aim of the present test was to develop a Pasteuria penetrans isolate (Pp3) on a Meloidogyne blend and compare the attachment and pathogenic potential of this heterogeneously produced isolate with other Pp3 isolates produced on individual Meloidogyne species (Meloidogyne javanica, M. incognita and M. arenaria). Number of spores attached varied among Meloidogyne spp. Pp3 isolate originally multiplied on M. javanica showed greater attachment level with second stage juveniles (J2s) of M. javanica (13.8) than other Meloidogyne spp. tested and lesser attachment was observed on J2s of a M. arenaria. The Pp3 isolate showed variable influence on the Meloidogyne spp. in suppressing root-knot disease. There was a significant difference in numbers of eggmasses produced by females of Meloidogyne spp. Higher numbers of eggmasses were recorded with females of M. arenaria (370) while fewer numbers of eggmasses were observed in treatment where M. javanica (245) was present. Root galling differed significantly among treatments (P0.01) and higher gall infestation was recorded in M. arenaria treatment (6.2) while lesser galling was observed in M. javanica treatment (4.4). Final female population also varied among treatments (P0.05) showing higher numbers of females in M. arenaria treatment (456) and fewer with M. javanica (398). Parasitism of females of Meloidogyne spp. by Pp3 differed significantly among treatments. Higher numbers of females infected with Pp3 spores were recorded among females of M. javanica (14.4) while lesser numbers of parasitized females were observed in M. arenaria treatment (9.8). There were significant variations in numbers of endospores/female produced by females of Meloidogyne spp. however egg set data did not differ in the treatments. The results showed that the Pp3 isolate was more pathogenic on M. javanica compared with other Meloidogyne spp. (M. incognita, M. arenaria and M blend). The Pp3 isolate was found compatible with different Meloidogyne spp. while M. arenaria proved the least good host to bacterial parasite

First Report of Natural Infection of Phlebotomus mongolensis to Leishmania major and Leishmania turanica in the Endemic Foci of Zoonotic Cutaneous Leishmaniasis in Iran.

The primary aim of this study is to determine infection to Leishmania parasites in the wild population of Phlebotomus caucasicus and Phlebotomus mongolensis using molecular methods in some important zoonotic cutaneous leishmaniasis foci in Iran. Sand flies were collected from active colonies of rodent burrows from 16 trapping sites using sticky trap paper. In order to detect and identify of Leishmania parasites in females Ph. caucasicus and Ph. mongolensis, the Nested-PCR amplification of ITS2-rDNA region was performed to generate amplicon with 245bp for Leishmania major, 206bp for L. gerbilli and 141bp for L. turanica. In the current study we found DNA of different gerbil parasites such as L. major and L. turanica, and mixed infection of L. major/L. turanica in Ph. caucasicus and Ph. mongolensis. It should be noted that, in Iran, natural infection with Leishmania parasites is recorded for the first time in this study in Ph. mongolensis. Both species of Ph. caucasicus and Ph. mongolensis not only may participate in the ZCL transmission cycle between reservoir hosts, but also results of this study support the role of these species as secondary vectors in the transmission of leishmaniasis to humans.

A case of natural infection with Dirofilaria immitis in a coati (Nasua narica) from Mexico.

This paper aims to describe the natural infection with Dirofilaria immitis in Nasua narica (white-nosed coati) from Yucatán, Mexico. Two carcasses of N. narica were collected on a highway that crosses through a dense forest with patches used for agriculture and livestock activities. We performed necropsies, and two female adult nematode parasites from the heart of one specimen were collected and preserved for their molecular identification using a conventional PCR directed at a fragment of the small subunit (18S) ribosomal RNA (18S-rRNA) gene. Bioinformatic analysis showed a similarity of 99 % with three sequences from D. immitis (two from Japan). Additionally, we performed a phylogenetic tree with the recovered sequence. All these analyses showed that D. immitis is present in N. narica from Mexico. The transmission of D. immitis toward populations of Nasua sp. may be due to indirect and accidental contact with domestic dogs or wild canids that share the same environment.

First report of the root-knot nematode Meloidogyne incognita on Salvia miltiorrhiza Bunge in Henan Province, China.

First report of the root-knot nematode Meloidogyne incognita on Salvia miltiorrhiza Bunge in Henan Province, China.

The Infestation of Fleas of the Long-Tailed Souslik with Entomoparasitic Nematodes in Tuva Mountain Natural Plague Focus

Entomoparasitic nematodes are supposed to be a link between parts of Yersinia pestis population in the environment and the flea vector. The aim of the study was to assess the prevalence and intensity of infestation in the fleas of the long-tailed souslik with entomoparasitic nematodes on the territory of Mongun-Taiginsky station in the Tuva natural plague focus. Materials and methods. Fleas were collected during the scheduled epizootiological surveys in 2019–2021. In the course of taxonomic identification the presence of parasitic nematodes was registered. In order to evaluate the intensity of nematode invasion, a total of 190 fleas were dissected. The number of adult parasitizing females and presence of larvae was recorded. Statistical processing of the data was performed with the help of conventional methods using the Excel software. The criterion χ2 was applied; the influence of various factors (species, gender of fleas) on the studied parameters was assessed through single- and two-factor analysis of variance. Results and discussion. During three years of observations, entomoparasitic nematodes were found in six species of fleas: Citellophilus tesquorum, Frontopsylla elatoides, Rhadinopsylla li transbaikalica, Frontopsylla hetera, Oropsylla alaskensis, and Neopsylla mana. The differences in infestation with nematodes between the species are presented. The highest invasion rate – 25.1–25.6 % – is observed in Rh. li transbaikalica. The gender of leas does not influence their infestation. It is established that invaded fleas are more often found in the nest than in the fur of animals, they are less actively migrate to the burrow entrance compared to not invaded ones. Evaluation of infestation prevalence has revealed that fleas Rh. li transbaikalica are the hosts for nematodes of mono- or oligoxenic species, which do not occur in other fleas.

Hatchability and Survival of Lamproglena clariae Fryer, 1956 Exposed to Increasing Concentrations of Aqueous Aluminium

The effect of increased aluminium concentration on the hatchability and survival of Lamproglena clariae is unknown. During October 2019 and October 2020, infected C. gariepinus were collected from the Vaal River and transferred to a controlled aquarium room. Parasite infection was established on acclimated C. gariepinus. Adult female parasites (F2 and F3 generation) on live fish were inspected for egg strings. Viable egg strings were removed, leaving females attached to produce more eggs. Bioassays were performed in varying concentrations of Al (control, 5 µg/L, 30 µg/L, 60 µg/L, and 120 µg/L). Egg development was monitored. In situ physical and chemical water quality parameters were measured, and water samples were collected every 24 h for metal analysis using inductively coupled mass spectrometry. The experiment terminated when all juveniles perished. Five percent of exposed eggs did not hatch in the control solution, compared to 26% in 120 µg/L Al. Hatchability and survival of L. clariae were negatively affected by increased Al concentrations. By removing this ectoparasite from living fish, the need to euthanise the host organism is eliminated, emphasising the usefulness of L. clariae as a bioindicator for metal pollution.

New drugs to squash the spread of malaria

The human-infecting malaria parasite, Plasmodium falciparum (green), is depicted erupting from human red blood cells (red). Eight sexually mature parasites (male gametes, green) emerge from the human cell (red), with their replicating DNA shown in blue. This image is courtesy of Dr Sabrina Yahiya and Prof. Jake Baum. For permission to reuse, contact Jake Baum at jake.baum@unsw.edu.au.Malaria is a devastating disease, with 247 million cases and 619,000 deaths reported in 2021 alone. Drugs to treat malaria symptoms and insecticides to kill the mosquito vector have improved in recent decades, but the parasite – Plasmodium falciparum - and the mosquitoes are evolving to become resistant to these strategies. Therefore, there is an urgent need for new antimalarial drugs with new modes of action. An attractive target is to prevent P. falciparum transmission to the mosquito vector, a process that depends on sexual maturation of male and female parasites from their dormant gametocyte form into gametes, known as gametogenesis.With this aim, the Baum laboratory have been investigating the mode of action of a new class of antimalarial sulphonamides – known as N-[(4-hydroxychroman-4-yl)methyl]-sulphonamide (N-4HCS) compounds – which have previously been shown to potently block male gametogenesis. The authors cultured gametocytes in human erythrocytes and treated them with one of the N-4HCS compounds to identify potential targets. Using photo-affinity labelling and mass spectrometry, the authors identified the gametocyte-specific parasitophorous vacuole membrane (PVM) protein Pfs16 as having the most significant interaction with this N-4HCS compound. The team then used complementary techniques to confirm that this N-4HCS compound binds and blocks Pfs16 function, which is known to be indispensable for male gametogenesis.The authors proceeded to explore the activity window of this N-4HCS compound in male gametocytes. They activated the process of gametogenesis, and then treated the male gametocytes with the N-4HCS compound at staggered time points up to 25 minutes, which is the point of male gamete maturation. Impressively, the N-4HCS compound was able to traverse the erythrocyte membrane and act within zero to six minutes of male gametogenesis initiation to prevent completion of the process. Probing further, the team used immunofluorescence imaging to show that the N-4HCS compound blocked P. falciparum cytoskeleton rearrangements and prevented Pfs16-dependent breakdown of the PVM, both of which are essential for male gametogenesis.Overall, Baum and colleagues have identified how this new class of antimalarials block male gamete formation and, therefore, malaria transmission. Once thoroughly developed and tested, there is potential for N-4HCS compounds to be given to malaria patients alongside existing symptomatic therapies, or even delivered directly to mosquitoes by coating nets or sugar baits – both of which could diminish subsequent infection of humans. More research is under way to explore and refine the activity of this class of sulphonamides, but, nevertheless, this study expands the breadth of strategies available to be used in the fight against malaria.

Reproductive behaviour of the branchial ectoparasite Bopyrus crangorum (Isopoda: Bopyridae) following ecdysis of the host Palaemon serrifer (Caridea: Palaemonidae)

Abstract The reproduction of bopyrid isopod parasites is thought to occur immediately following host ecdysis, but direct observations supporting this hypothesis are limited. The aim of this study was to describe the reproductive behaviour of the bopyrid isopod Bopyrus crangorum relative to host ecdysis based on video recordings. Several hours after host ecdysis, biphasic moulting of female parasites was observed. The cuticle of the posterior body was shed before that of the anterior body at an interval of 1 h. Two hours after female moulting, the male repeatedly moved from its initial position between the female pleopods and stopped at the anterior end of the fifth oostegite, immediately above the gonopore. To our knowledge, this repeated visiting behaviour by males has not been previously observed in bopyrid isopods. Oviposition through the female gonopore occurred 33 min later. The male-removal experiment showed that females with their males removed after visits to the gonopore oviposited eggs, whereas females with their males removed before visits did not. We propose that repeated visits by males to the gonopore are attempts to inseminate the female. We hypothesised that sperm are released onto the external surface of each gonopore and that the eggs are fertilised as they pass through the opening, which would explain the synchronous development of fertilised eggs inside the marsupium. The present study provides new information on the life history of bopyrid isopods, which allows for a better understanding of the host–parasite relationship.

A Novel Rhabdovirus Associated with the Idaho Population of Potato Cyst Nematode Globodera pallida.

Globodera pallida, a potato cyst nematode (PCN), is a quarantine endoparasitic pest of potato (Solanum tuberosum) in the US due to its effects on yield and quality of potato tubers. A new rhabdovirus, named potato cyst nematode rhabdovirus (PcRV), was revealed and characterized in the G. pallida populations collected in Idaho through use of high-throughput sequencing (HTS) and RT-PCR and found to be most closely related to soybean cyst nematode rhabdovirus (ScRV). PcRV has a 13,604 bp long, single-stranded RNA genome encoding five open reading frames, including four rhabdovirus-specific genes, N, P, G, and L, and one unknown gene. PcRV was found present in eggs, invasive second-stage juveniles, and parasitic females of G. pallida, implying a vertical transmission mode. RT-PCR and partial sequencing of PcRV in laboratory-reared G. pallida populations maintained over five years suggested that the virus is highly persistent and genetically stable. Two other Globodera spp. reproducing on potato and reported in the US, G. rostochiensis and G. ellingtonae, tested negative for PcRV presence. To the best of our knowledge, PcRV is the first virus experimentally found infecting G. pallida. Based on their similar genome organizations, the phylogeny of their RNA-dependent RNA polymerase domains (L gene), and relatively high identity levels in their protein products, PcRV and ScRV are proposed to form a new genus, provisionally named "Gammanemrhavirus", within the family Rhabdoviridae.

Mate choice is affected by parasite infestation rate of the choosing individual as well as of potential mating partners.

Parasites are known to be a key driving force in mate choice and are important for the expression and evolution of ornaments and behavioral traits being used. However, there is little experimental evidence on how the parasite's burden of the choosing individual is integrated into the mate-choice process and how it affects decision-making, especially in relation to parasite infestation of potential mates. Thus, the aim of our study was to determine whether female house sparrows Passer domesticus adjust their mate preference according to their own as well as the parasite load of prospective partners. To do this, we experimentally manipulated female parasite load and determined their mate preferences prior to and after parasite treatment. We manipulated the chronic coccidian parasite burden of females either by initiating the acute infection phase via re-infecting them with coccidian or by temporally reducing the parasite load of coccidia. We then measured the effect of this manipulation on mate preference by presenting females with a choice of four stimuli: three males with similar ornaments, but unmanipulated, naturally varying chronic coccidiosis levels, and an unmanipulated control female. Additionally, we recorded some males' behavior in relation to their infection status pointing toward an increased or reduced interest in mating. We found that females preferred highly infested males prior to manipulation, regardless of their own infestation level. However, after manipulation, infested females avoided highly infested males probably in response to the deterioration of their health condition by parasites. Our study suggests that mate-choice decisions are more complex when they are mediated by parasites. The implications of parasites for evolutionary theories of sexual signaling and mate choice are discussed.

Status of Intestinal Schistosomiasis in Buffaloes and Cattle in Rajshahi, Bangladesh

Schistosoma infection causes serious health impediment in livestock with poor productive and reproductive performances. This study was carried out to know the status of Schistosoma infection in buffaloes and cattle in Rajshahi, Bangladesh. The adult schistosomes were collected from mesenteries of buffaloes and cattle of Rajshahi. Out of 240 mesenteries (120 from each species) examined, 113 (47.08%) were found infected. The infection rate in buffaloes and cattle were 54.16% and 40%, respectively. Female buffalo and cattle (57.69% and 46%) were more prone to the infection than male (51.47% and 36.71%) although the differences were not statistically significant. Significant variations (p<0.05) were observed in infection rate in different season. The highest infection rate was observed in rainy season (85% and 65%) followed by summer (52.5% and 40%) and winter (25% and 15%) in both the animals. Intensity of the infection greatly varied. Mostly, half of the infected animal (55% buffalo and 46% cattle) showed moderate infection intensity (51 to 100 parasites/animal). High degree of infection (>100 parasites/animal) was found in 25% and 33% infected buffalo and cattle, respectively. Two species of intestinal schistosomes (S. indicum and S. spindale) were identified microscopically by observing egg of female parasites. S. indicum was present in all the infected mesenteries whereas only 29% buffaloes and 35% cattle samples contained S. spindale. The study determined the current scenario of intestinal schistosome infection in buffaloes and cattle of Rajshahi. The findings might be helpful to develop effective strategic plan to overcome the harmful effects of schistosomes in livestock of Bangladesh.
 Vol. 9, No. 2, August 2022: 201-211

The scale of competition impacts parasite virulence evolution

The structure of parasite populations can have important consequences for virulence evolution. Both the scale of competition, whether it is more intense in the within versus between host environment, and the mode of transmission, whether parasites transmit alone or in groups between hosts, influence population structure and can select for changes in virulence.In a selection experiment, we evolved metapopulations of the spider mite parasite Tetranychus urticae, under local (fixed sampling per host patch) or global (sampling determined by host patch productivity) competition, with either co- (with a female parasite from the same host patch) or random (with parasites from different host patches) transmission. After 33 generations of evolution, the fecundity and virulence of each replicate population was measured.Females from the ‘local-random’ regime were more virulent with higher fecundity than females from the ‘global-random’ regime. There was no difference in virulence or fecundity between females from the ‘global-random’ or ‘global co-transmission’ selection regimes.These results show that the scale of competition, and not the type of transmission, impacted virulence evolution for T. urticae. Local competition may maintain higher levels of genetic diversity at the level of the metapopulation. As such, intense local, within-host, competition selected for more productive individuals better able to exploit their environment and be the one to transmit to a new host.

STUDIES ON THE POSSIBLE ROLE OF PLANT HOST ON THE DEVELOPMENT OF ROOT-KNOT NEMATODE, MELOIDOGYNE JAVANICA AND PASTEURIA PENETRANS AS AFFECTED BY DIFFERENT HARVESTING DATES

There were strong interactions between plant-hosts and Pasteuria (P0.01) on numbers of eggmasses, root galling and numbers of eggs/eggmass produced by females of Meloidogyne javanica after 422, 595 and 767 degree days after first, second and third harvests. The presence and absence of the biocontrol agent (Pasteuria penetrans) in the treatments influenced these parameters and it was also influenced by plant hosts. After the first harvest, there were significant differences in the above-mentioned parameters between P. penetrans and control treatments (P0.01). There was lesser root galling (3.13) in the treatments where P. penetrans was applied compared with untreated control (5.53). Plant hosts also differed significantly in root galling (P0.01) and the interaction between plant-host and Pasteuria was non-significant (P0.05). After the second harvest, there were significant differences between Pasteuria and control treatments in these parameters. Plant-hosts differed significantly in numbers of eggmasses and root galling (P0.01) and there was no interaction between plant-host and Pasteuria (P0.05) regarding eggmasses and root galling. After the third harvest, there were significant differences between Pasteuria and control treatments in the production of eggmasses (P0.01), root galling, and the number of eggs/eggmass (P0.01). There were fewer eggmasses (379) and lesser galling (5.1) in the treatments where P. penetrans was applied. Plant-hosts differed significantly in numbers of eggmasses and root galling (P0.01). However, there was no interaction between plant-host and Pasteuria (P0.05) regarding eggmasses and root galling. Contrarily, a significant interaction between plant-hosts and Pasteuria (P0.01) and greater numbers of eggs were observed among females developed on tomato in the presence (385) and absence (629) of Pasteuria. The rate of parasitism of M. javanica was very low and there was no P. penetrans infection after 422-degree days as neither vegetative stages nor mature endospores were observed in females. After 595-degree days, few females were observed having vegetative stages of the bacterium. The parasitism of females was only observed though very low after 767-degree days and females reared on okra were infected in greater numbers than those reared on tomato and eggplant.

Have female twisted-wing parasites (Insecta: Strepsiptera) evolved tolerance traits as response to traumatic penetration?

Traumatic insemination describes an unusual form of mating during which a male penetrates the body wall of its female partner to inject sperm. Females unable to prevent traumatic insemination have been predicted to develop either traits of tolerance or of resistance, both reducing the fitness costs associated with the male-inflicted injury. The evolution of tolerance traits has previously been suggested for the bed bug. Here we present data suggesting that tolerance traits also evolved in females of the twisted-wing parasite species Stylops ovinae and Xenos vesparum. Using micro-indentation experiments and confocal laser scanning microscopy, we found that females of both investigated species possess a uniform resilin-rich integument that is notably thicker at penetration sites than at control sites. As the thickened cuticle does not seem to hamper penetration by males, we hypothesise that thickening of the cuticle resulted in reduced penetration damage and loss of haemolymph and in improved wound sealing. To evaluate the evolutionary relevance of the Stylops-specific paragenital organ and penis shape variation in the context of inter- and intraspecific competition, we conducted attraction and interspecific mating experiments, as well as a geometric-morphometric analysis of S. ovinae and X. vesparum penises. We found that S. ovinae females indeed attract sympatrically distributed congeneric males. However, only conspecific males were able to mate. In contrast, we did not observe any heterospecific male attraction by Xenos females. We therefore hypothesise that the paragenital organ in the genus Stylops represents a prezygotic mating barrier that prevents heterospecific matings.

Experimental removal of nematode parasites increases growth, sprint speed, and mating success in brown anole lizards.

Parasites interact with nearly all free-living organisms and can impose substantial fitness costs by reducing host survival, mating success, and fecundity. Parasites may also indirectly affect host fitness by reducing growth and performance. However, experimentally characterizing these costs of parasitism is challenging in the wild because common antiparasite drug formulations require repeated dosing that is difficult to implement in free-living populations, and because the extended-release formulations that are commercially available for livestock and pets are not suitable for smaller animals. To address these challenges, we developed a method for the long-term removal of nematode parasites from brown anole lizards (Anolis sagrei) using an extended-release formulation of the antiparasite drug ivermectin. This treatment eliminated two common nematode parasites in captive adult males and dramatically reduced the prevalence and intensity of infection by these parasites in wild adult males and females. Experimental parasite removal significantly increased the sprint speed of captive adult males, the mating success of wild adult males, and the growth of wild juveniles of both sexes. Although parasite removal did not have any effect on survival in wild anoles, parasites may influence fitness directly through reduced mating success and indirectly through reduced growth and performance. Our method of long-term parasite manipulation via an extended-release formulation of ivermectin should be readily adaptable to many other small vertebrates, facilitating experimental tests of the extent to which parasites affect host phenotypes, fitness, and eco-evolutionary dynamics in the wild.