Natural Parasite Research Articles

New host plant record, first report of natural parasitisation, report of ‘parasitoid guarding’ behaviour with notes on biology and identification of Thyrassia virescens (Hampson, 1892) (Insecta: Lepidoptera: Zygaenidae)

ABSTRACT Caterpillars of Thyrassia virescens (Hampson, 1892) were collected from a newly recorded host plant Cissus quadrangularis Linnaeus, 1767 (Vitaceae) in Chikaballapura district of Karnataka State in India from June to September 2021. Larvae were reared in room condition to study the life cycle. The total larval period was found to be 18–22 days with four instars. The pupal period was found to be 10–12 days. Parasitisation by Cotesia sp. (Braconidae: Hymenoptera) on the caterpillars of T. virescens has been documented for the first time. While there was no parasitisation occurred during the first generation, the second and third generations showed 93.3% and 18.18% parasitisation respectively. Notes on the identification features such as the male and female genitalia have been described. An interesting ‘parasitoid-guarding’ behaviour has been documented, in which the caterpillars seem to protect the parasitoid cocoon from hyper-parasitoids and other enemies until the emergence of parasitoid adult.

Natural Parasitism Influences Biological Control Strategies Against Both Global Invasive Pests Ceratitis capitata (Diptera: Tephritidae) and Drosophila suzukii (Diptera: Drosophilidae), and the Neotropical-Native Pest Anastrepha fraterculus (Diptera: Tephritidae).

Ceratitis capitata (Wiedemann) and Drosophila suzukii (Matsumura) are two severe invasive pests widespread in all Argentinean fruit-producing regions. Both coexist with the Neotropical pest Anastrepha fraterculus (Wiedemann) in northern Argentina. The northwestern region shelters major soft fruit and Citrus producing and exporting industries, which are heavily affected by these dipterans. Eco-friendly strategies are under assessment in Argentina. This study mainly assessed D. suzukii, C. capitata, and A. fraterculus temporal abundance variations and their natural parasitism levels on a 1.5-ha-patch of feral peach trees within a disturbed secondary subtropical rainforest of northwestern Argentina. Fly puparia were mainly collected from the soil under fallen peach. Sampling was performed over three peach fruiting seasons. The most abundant pest species was C. capitata. Drosophila suzukii was only found in the last collecting period, but outnumbered A. fraterculus. Natural parasitism distinctly affected the temporal abundance of these dipterans: it significantly depressed C. capitata abundance in last sampling weeks, it did not substantially affect D. suzukii abundance, but it increased synchronously with the increase in the A. fraterculus abundance. Parasitism on C. capitata was mostly exerted by a combination of both a cosmopolitan pupal and a native larval parasitoid, while A. fraterculus was mainly parasitized by two indigenous larval parasitoids. Only three resident pupal parasitoids were associated with D. suzukii, of which the cosmopolitan Pachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) was the most significant. Data on the resident parasitoid impact are relevant for designing biocontrol strategies in noncrop habitats.

What we know and don't know about the invasive zebra (Dreissena polymorpha) and quagga (Dreissena rostriformis bugensis) mussels.

We summarized existing knowledge on Dreissena polymorpha (the zebra mussel) and D. r. bugensis (the quagga mussel), including data on their taxonomy, systematics, evolution, life cycle, reproduction, feeding, growth and longevity, population dynamics, interspecific competition, habitat requirements, and distribution within and among waterbodies. We analyzed the history of spread of both species and the major pathways and vectors of their spread in Europe and North America. Special consideration was given to their ecological and economic impacts and their natural enemies, like waterfowl, fishes, and parasites, as well as the prevention of their introduction, early detection, control, and containment. We also outlined the most salient ecosystem services provided by zebra and quagga mussels, including water purification, nutrient recycling, culling the effects of eutrophication, biomonitoring, and their role as a food resource for fish and waterfowl. Finally, we identified major knowledge gaps and key studies needed to better understand the biology, ecology, and impacts of these aggressive freshwater invaders. Our review indicates that much crucial information on the quagga mussel is still missing, including key life history parameters, like spawning cues, fecundity, and longevity, particularly for the profundal zone of deep lakes.

Serodiagnosis and therapeutic monitoring of New-World tegumentary leishmaniasis using synthetic type-2 glycoinositolphospholipid-based neoglycoproteins

ABSTRACT American tegumentary leishmaniasis (TL) caused by Leishmania braziliensis is characterized by a spectrum of clinical presentations, ranging from localized cutaneous ulcers (CL), mucosal (ML), or disseminated (DL) disease, to a subclinical (SC) asymptomatic form. Current diagnosis based on parasite culture and/or microscopy lacks sensitivity and specificity. Previous studies showed that patients with CL and ML have very high levels of Leishmania-specific anti-α-Gal antibodies. However, the native parasite α-Gal glycotope(s) is(are) still elusive, thus they have not yet been explored for a more accurate TL diagnosis. Using a chemiluminescent immunoassay, we evaluated the seroreactivity of TL patients across its clinical spectrum, and of endemic (EC) and nonendemic healthy controls (NEC) against three synthetic neoglycoproteins (NGP29b, NGP30b, and NGP28b), respectively comprising the L. major-derived type-2 glycoinositolphospholipid (GIPL)-1 (Galfβ1,3Manα), GIPL-2 (Galα1,3Galfβ1,3Manα), and GIPL-3 (Galα1,6Galα1,3Galfβ) glycotopes. Contrary to NGP29b and NGP30b, NGP28b exhibited high sensitivity and specificity to a CL serum pool. More importantly, NGP28b reacted strongly and specifically with individual sera from distinct clinical forms of TL, especially with SC sera, with 94% sensitivity and 97% specificity, by post-two-graph receiver-operating characteristic curve analysis. Contrary to NGP29b, NGP28b showed low cross-reactivity with Chagas disease and control (NEC/EC) sera. Additionally, seroreactivity of CL patients against NGP28b was significantly decreased after successful chemotherapy, indicating that L. braziliensis-specific anti-α-Gal antibodies may serve as an early biomarker of cure in CL. Our data also points towards the applicability of L. major type-2 GIPL-3-derived Galα1,6Galα1,3Galfβ glycotope for the serological diagnosis of American TL, particularly of the subclinical form.

Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) in Minho (Northern Portugal): Bioecology, Native Parasitoid Communities and Biological Control with Torymus sinensis Kamijo (Hymenoptera: Torymidae)

The Asian chestnut gall wasp Dryocosmus kuriphilus Yasumatsu, native to China, was first detected in Europe in Italy in 2002. In Portugal it was declared in 2014, and it has since affected the Portuguese chestnut production. The introduction of its natural parasitoid Torymus sinensis Kamijo started through inoculative releases according to the National Action Plan for the Control of Dryocosmus kuriphilus, established by the Direção Geral de Alimentação e Veterinária (DGAV), in 2015. This research was carried out during 2018 and 2019, in five chestnut orchards in the Minho region (Northern Portugal). Between January and March 2018, at each location, three monthly harvests of 100 buds were carried out to determine the infestation level. Between April and June 2018, 240 galls were harvested every two weeks, with the purpose of studying the bioecology of D. kuriphilus. In each sampling site, 160 galls were placed in emergence boxes to follow adults of the D. kuriphilus population, and 80 galls were dissected with a binocular magnifying glass, to count and record the evolution of the larval stages of D. kuriphilus and of the parasitoids. The identification of T. sinensis and native parasitoids was carried out. The parasitism rates and Simpson diversity indices were determined. The percentage of buds infested by D. kuriphilus was high in all studied places, varying between 67% and 80%, regardless of the number of T. sinensis releases made and of the chestnut cultivars present in each orchard. The highest rate of parasitism by T. sinensis was 0.5044% and it was recorded in an orchard where there were two releases of T. sinensis in 2016 and 2017 (Arcos de Valdevez—Rio Cabrão—P1). Considering that the exotic parasitoid has already been released in the region since 2016, its establishment in all the chestnut orchards studied was confirmed, although with very low parasitism rates. The natural parasitism associated with the native parasitoid species of D. kuriphilus was confirmed in this work, recording values between 34% and 51% of the parasitized chestnut galls, with 11 species of native parasitoids having been identified: Eupelmus azureos, Eupelmus uruzonus, Eurytoma brunnivientris, Eurytoma pistaciae, Megastigmus dorsalis, Mesopolobus sp., Ormyrus pomaceus, Sycophila biguttata, Sycophila iracemae, Sycophila variegatta and Torymus flavipes.

The honey bees immune memory

Invertebrates' immune priming or innate immune memory is an analogous response to the vertebrates' adaptive memory. We investigated if honey bees have immune memory. We compared survival and immune response between bees that were: 1) manipulated (Naïve), 2) challenged twice with the same pathogen Escherichia coli (Memory), 3) challenged twice with different pathogens (Staphylococcus aureus versus E. coli, Micrococcus lysodeikticus versus E. coli), or 4) with PBS (the diluent of bacteria) versus E. coli (heterologous challenge; Control). Results indicate better survival in the Memory than the Control group, and the Memory group showed a similar survival than Naïve insects. The Memory group had higher lytic activity but lower prophenoloxidase, phenoloxidase activity, and hemocyte count than the Control and Naïve groups. No differences were found in relative expression of defensin-1. This first demonstration of immune memory opens the questions about its molecular mechanisms and whether, immune memory could be used against natural parasites that affect honey bees, hence, if they could be “vaccinated” against some natural parasites.

Artifices of Anastrepha obliqua (Macquart, 1835) (Diptera: Tephritidae) for survival in umbu, endemic fruit from Brazil

We studied the interaction involving umbu, fruit flies and parasitoids in the Brazilian cerrado biome in Piauí state. The fruits were collected in Baixa Grande do Ribeiro and Uruçuí in the period from February to April 2013 and were analyzed in Laboratory. In this study is being published the first occurrence of Anastrepha obliqua (Macquart, 1835) in umbu fruits and two parasitoids, Aganaspis pelleranoi (Brèthes, 1924) and Opius bellus (Gahan, 1930), in Piauí. Where 77.8 % of the fruits were infested by A. obliqua, with 149.4 pupae / kg (2.4 pupae / fruit) and the parasitism rate was 2.7 %. Natural parasitism is not very significant, however, less pupae were found in fruits with parasitized larvae, suggesting that the fly avoids oviposition. Additionally , it was found that the A. obliqua performs multiple oviposition in umbu during host selection and multiple infestations is a factor that increases the likelihood of emergence of A. obliqua during the colonization of umbu. The tritrophic interaction among S. tuberosa, A. obliqua and O. bellus was discussed.

Spillover and spillback risks of ectoparasites by an invasive squirrel Callosciurus erythraeus in Kanto region of Japan.

Invasive organisms can alter host-parasite relationships in a given ecosystem by spreading exotic parasites and/or becoming a new reservoir for native ones. Since these problems affect management programs of the invasive host organisms, it is necessary to monitor them individually. The Pallas's squirrel Callosciurus erythraeus is an invasive arboreal mammal introduced into Japan that threatens to exacerbate ecological and public health problems by spreading native and exotic parasites. However, only limited surveys have been available especially for ectoparasites, using the traditional combing method in which the possibility of oversight is inherent. Here, we evaluated the ectoparasite occurrences in Kanto region of Japan, using the whole-shaving method as an alternative approach. As a result of examining 52 hosts from two invaded districts (Yokohama and Yokosuka), chigger mites (Leptotrombidium spp.) and fleas (Ceratophyllus anisus and Ceratophyllus indages indages) were newly recovered in addition to the previously reported tick (Haemaphysalis flava) and exotic lice (Enderleinellus kumadai and Neophaematoponis callosciuri). The parasite burdens were higher in Yokosuka and in male host individuals, affecting infracommunity richness and composition. Our findings on the variety of native and exotic ectoparasites, at higher abundances in some cases than previously known, may suggest that both the spillover and spillback risks need to be adjusted upwards.

Recruitment and Seasonal Occurrence of Parasites in Juvenile Invasive Round Gobies (Neogobius melanostomus) in the St. Lawrence River, Quebec, Canada

The round goby (Neogobius melanostomus) is an invasive species that has become one of the most abundant fish in the St. Lawrence River, Quebec, Canada over the past 15 yr. Since its introduction, the round goby has acquired a number of native parasites, yet little is known about the dynamics of parasite recruitment. To examine this question, young-of-the-year and juvenile round gobies were collected monthly from 2 localities in the river (Îles de la Paix, Île Dorval) from June through November 2012. At Îles de la Paix, round gobies (n = 180) were infected with 3 species of parasites, all larval stages (Diplostomum spp., Tylodelphys scheuringi, Neoechinorhynchus tenellus). Prevalence of the digenean Diplostomum spp. varied from 3.3 to 13.3%, and mean abundance from 0.03 to 0.53 from June through September, with a maximum in August. The digenean T. scheuringi was seen only in August, at a prevalence of 10.0% and a mean abundance of 0.53. The acanthocephalan N. tenellus was observed in June, August, and September, prevalence ranging from 3.3 to 10.0% and mean abundance from 0.03 to 0.27. Maximum infection for all 3 species occurred in August. All infected fish were ≥44 mm in total length (TL). Fish infected with more than 1 parasite species were >60 mm TL. No round goby (n = 178) was infected at Île Dorval. This study demonstrated that the invasive round goby starts to acquire parasite infections in the St. Lawrence River in the first year of life and may contribute to the transmission of some parasites within this ecosystem.

Irrigation Scheduling and Weed Management: A Sustainable Approach for Managing Broomrape and Other Weeds in Tomato Crop

Broomrape (Orobanche cernua L.) is an obligate root parasitic weed that significantly reduces the qualitative and yield attributes of tomatoes globally. The efficient management of broomrape is challenging because of its complicated parasitic nature. Field trials were conducted to assess the influence of various irrigation scheduling and weed control strategies on broomrape, weed presence, and tomato productivity. The experiment was conducted with a randomized complete block design (RCBD) with a split-plot arrangement and was replicated three times. Three irrigation intervals (3, 6, and 9 days) were assigned to the main block, while sub-blocks including treatments and year were taken as the source of variance (year × irrigation timing × treatments). The experiment comprised sixteen treatments, including transparent polythene, black polythene, weedy check (Control), sole weeding of broomrape only, weeding of all weeds, weeding except broomrape, humic acid 25 kg ha−1+ copper oxychloride in single and split doses, copper oxychloride (1.5 kg a.i ha−1 in single and split doses), ammonium sulphate 200 kg ha−1 in single and split doses, copper sulfate (2 kg ha−1 in single/split doses), and glyphosate 48 SL (1.5 kg a.i ha−1) and pendimethalin 33 EC (1.44 kg a.i ha−1). The results revealed that among the various irrigation intervals, the highest broomrape intensity (4.34 plant−1) was observed with a9-day irrigation interval. Similarly, the highest weed density (35 m−2) resulted in a3-day irrigation interval. Furthermore, irrigation at a 6-day interval increased the plant height by 11%, fruit yield tons ha−1 by 24.9 %, and produced the highest cost/benefit ratio (CBR) of (1:4). Black polythene, transparent polythene, and pendimethalin reduced the weed density by 92%, 89%, and 84%;weed dry biomass by 97%, 95%, and 91%; and broomrape intensity by 67%, 77%, and 28%. Conversely, the plant height increased by 24%, 23%, and 23.6%; and fruit yield by 286%, 270%, and 191%; and had the highest CBR of 1:5, 1:4, and 1:4, respectively, as compared to the weedy check. Consequently, an increase in irrigation frequency increases other weed densities and decreases the broomrape intensity plant−1 of tomato. Therefore, black polythene could be recommended in a severely broomrape-infested field. Moreover, irrigation at 6-day intervals combined with pendimethalin and ammonium sulfate fertilizers revealed the lowest incidence of broomrape and other weeds and produced an economic yield.

Human-Borne Pathogens: Are They Threatening Wild Great Ape Populations?

Simple SummaryHuman-driven activities, including agriculture, forestry, and mining, are destroying the natural habitats of wild great ape (bonobo, chimpanzee, gorilla, and orangutan) populations in Africa and Southeast Asia. The reduction in and fragmentation of wild great ape environments lead to (i) a decrease in population numbers, (ii) the isolation of current populations, and (iii) increased exposure to humans and their livestock. Consequently, the spatial overlap between humans and wild great apes might facilitate the transmission of infectious agents between them. Historically, animal-to-human pathogen transmission has attracted most of the attention of researchers and public health authorities. Only in recent years has the human-to-animal transmission pathway acquired notoriety, mainly due to conservation concerns. In this review, we examine and appraise literature-based evidence reporting wild great ape infections with viral, bacterial, parasitic, and fungal pathogens of potential anthropic nature. We select and further discuss two viral (Human Metapneumovirus and Respiratory Syncytial Virus), one bacterial (diarrhoeagenic Escherichia coli), and two parasitic (Cryptosporidium spp. and Giardia duodenalis) pathogens causing infections in wild great ape populations for which a human origin is most likely. Gaps in knowledge and future research directions are also identified.Climate change and anthropic activities are the two main factors explaining wild great ape habitat reduction and population decline. The extent to which human-borne infectious diseases are contributing to this trend is still poorly understood. This is due to insufficient or fragmented knowledge on the abundance and distribution of current wild great ape populations, the difficulty obtaining optimal biological samples for diagnostic testing, and the scarcity of pathogen typing data of sufficient quality. This review summarises current information on the most clinically relevant pathogens of viral, bacterial, parasitic, and fungal nature for which transmission from humans to wild great apes is suspected. After appraising the robustness of available epidemiological and/or molecular typing evidence, we attempt to categorise each pathogen according to its likelihood of truly being of human origin. We further discuss those agents for which anthroponotic transmission is more likely. These include two viral (Human Metapneumovirus and Respiratory Syncytial Virus), one bacterial (diarrhoeagenic Escherichia coli), and two parasitic (Cryptosporidium spp. and Giardia duodenalis) pathogens. Finally, we identify the main drawbacks impairing research on anthroponotic pathogen transmission in wild great apes and propose research lines that may contribute to bridging current knowledge gaps.

Avoiding the Delusions of Today’s Capitalism with a Thorough Understanding of Marxism as the Key

ABSTRACT Between the early 1970s, when neoliberalism was in full swing and became the dominant rhetoric of the time, and the 2008 global economic crisis, capitalism as a result of its inherent nature entered a fundamental crisis with unavoidable consequences. Many in-depth analyses of the economic crisis from a Marxist viewpoint have revealed that in the area of wealth appropriation, capitalism has now exacerbated inequality to absurd levels. This is not to mention other challenging issues such as the parasitic nature of increasingly digitized finance capital, uncontrolled inflation leading to rampant financial deficits, the worsening ecological crisis with mounting environmental costs that erode profits, escalating political manipulation by monopoly capitalists, and the mounting by developed countries of inappropriate military interventions in the developing world, to name just a few. Today, the fundamental characteristics and specific manifestations of contemporary capitalism are exerting significant impacts on the process of building socialism worldwide. Faced with today’s capitalism, China and Vietnam while exercising due caution must put forward and consistently highlight the need to examine the direction the system is taking. Thorough research on this subject is critical for a correct scientific understanding.

New record of aphanogmus clavicornis Thomson (Hymenoptera: Ceraphronidae) as a larval parasitoid of tomato leaf miner Tuta absoluta (Meyrick) in Syria

Tomato (Solanum lycopersicum L.) is an important edible and nutritious fruit regarded by nutritionist as a vegetable. It is an important source of vitamins and significantly contributes to economic development. However, the production of tomatoes is heavily affected by climate change, insect pests, disease and the new devastating pest of tomatoes, the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). This study includes a description of Aphanogmus clavicornis Thomson, 1858 (Hymenoptera: Ceraphronoidea), a primary parasitoid of T. absoluta whose larvae feed on all parts of the tomato plant. It is the first record of T. absoluta as a host of genus Aphanogmus worldwide and a first record of A. clavicornis in both Syria and the Middle East. Description, biology and the taxonomic characters of the new species were provided. The new record of natural parasitism of T. absoluta by A. clavicornis would add knowledge on biological control of the pest and could become an additional option for the integrated pest management of those crops where T. absoluta is a key pest. This finding will be baseline for future research. It would be interesting to investigate if A. clavicornis can be produced in large scale under laboratory conditions and test its potential use as a biological control agent within integrated pest management programs.

Behavioural responses of wild anadromous Arctic char experimentally infested in situ with salmon lice

Abstract Salmon lice can impact the marine behaviour, growth, and survival of salmonids, but little is known about their effects on Arctic char. We present behavioural responses from the first dose-response experiment with wild anadromous Arctic char (n = 50) infested in situ with salmon lice (0.0–1.2 lice g−1 fish) in an area with low natural infestations. Infested fish spent less time at sea (mean ± SD = 22 ± 6 d) than non-infested fish (mean ±SD = 33 ± 5 d), and a significant dose response was evident, with even very low louse burdens (<0.05 lice g−1 fish) reducing the marine feeding time. Furthermore, a negative correlation was present between time spent close to their native watercourse and parasite burden, suggesting that salmon lice influence the marine habitat use of Arctic char. No impact of salmon lice was evident on the return probability, i.e. marine survival. However, the presence of louse-induced mortality cannot be excluded as the modest sample size was only sufficient to detect extreme effects. Reduced marine feeding time and altered marine habitat use will likely have substantial negative effects on growth and fitness, suggesting that impacts of salmon lice must be considered in the conservation of anadromous Arctic char.

Contrasting parasite-mediated reductions in fitness within versus between patches of a nematode host.

Host and parasites interact across spatial scales, but parasite‐mediated fitness effects are typically measured only at local scales. Recent work suggests that parasites can reduce host fitness during dispersal between patches, highlighting the potential for both within‐ and between‐patch effects to contribute to the net fitness consequences of parasitism. Building on this work, we measured the contribution of the dispersal phase to parasite‐mediated reductions in host fitness. We used the nematode Caenorhabditis elegans and its natural microsporidian parasite Nematocida parisii to quantify the fitness consequences of parasitism at the individual, population, and metapopulation level. Nematocida parisii reduced individual fecundity and population growth but had its greatest fitness impact at the dispersal stage: parasitism reduced the fitness of dispersing larvae by 62%–100%. These results indicate that the cost of parasitism in this system is greatly underestimated if the metapopulation level is not taken into account. We also found that the effects of N. parisii vary with host genotype, and the relative advantage of the most resistant genotype increases with inclusion of the dispersal stage. Taken together, our findings demonstrate that host‐parasite interactions at the dispersal stage can magnify selection for parasite resistance.

Myxozoan Diversity Infecting Ornamental Fishes Imported to Australia

The ornamental fish trade provides a pathway for the global translocation of aquatic parasites. Myxozoa is comprised of highly specialized metazoan parasites of aquatic hosts with a wide host range. Interest in the group has intensified along with the development of aquaculture due to emergent pathogenic myxozoan species in both freshwater and marine environments. However, little is known on myxozoan diversity in the ornamental fish trade. We examined 630 ornamental fish imported from Asia to Australia (representing 24 fish populations, including freshwater and wild caught marine fish species) for myxozoan parasites during 2015. Fish were sampled under Australian quarantine following veterinary certification that they showed no clinical signs of pests and diseases from the exporting country and visual inspection at Australian border control. Myxozoan parasites infected 8 of 12 freshwater populations and 8 of 12 marine fish populations. A total of 12 morphologically distinct Myxobolus spores were detected amongst all goldfish, Carassius auratus populations. Myxidium spores were detected in kissing gourami, Helostoma temminckii, and Ceratomyxa sp. spores were detected in cardinal fishes, Cheilodipterus quinquelineatus, Pterapogon kauderni, and Zoramia leptocantha. Kudoa sp. spores were detected in C. quinquelineatus, Sphaeramia nematoptera and Z. leptocantha. Results of this study show that Australian pre-export health requirements and visual inspections do not reliably detect myxozoan infections. Inspection prior to exportation and at border control should account for the highly cryptic nature of myxozoan parasites and consider alternative detection methods to complement inspections at border control.

Parasites of Selected Freshwater Snails in the Eastern Murray Darling Basin, Australia.

Aquatic snails serve an important role in the ecosystem. They also play an essential role in the life cycle of many parasites as hosts and may pose risks to animal and human health. In Australia, the role of snails in the transmission of parasites of livestock is well studied. However, despite the country’s unique biodiversity and wildlife, little is known about the role of snails in the transmission and survival of parasites in other ecosystems, including aquatic and aquaculture systems. This study aimed to determine the occurrence of parasites in freshwater snails in the eastern Murray Darling Basin. A total of 275 snails were collected from various localities, including aquaculture fishery ponds and natural creeks during the summer and autumn months in the southern hemisphere. Three different species of freshwater snails, all common to the area, were found, including Bullastra lessoni (n = 11), Isidorella hainesii (n = 157), and Haitia acuta (n = 107), of which 9.1%, 1.3%, and 4.7%, respectively, were found to be harboring various developmental stages of Trematoda. No other parasite was found in the examined snails. Parasites were identified as Choanocotyle hobbsi, Plagiorchis sp. and Petasiger sp. based on the sequences of their ITS2, 18S, and 28S ribosomal DNA region. Herein, we report a native parasite Choanocotyle hobbsi in an introduced snail, Haitia acuta, from both natural and aquaculture ponds. As there are no genetic sequences for adult specimens of Petasiger spp. and Plagiorchis spp. collected in Australia for comparison, whether the specimens collected in this study are the larval stage of one of the previously described species or are a new, undescribed species cannot yet be determined. Our results also suggest snails collected from aquaculture ponds may be infected with considerably more parasites.

Natural Egg Parasitism by Scelionidae on a Phycitine Cactus Moth in Mexico

La detección de enemigos naturales nativos que pueden utilizar a Cactoblastis cactorum como hospedero, es relevante tras su invasión a Norteamérica. Detectamos avispas (Scelionidae) parasitando huevos de Melitara cf. junctolineella (una polilla del cactus en Phycitini estrechamente relacionada con C. cactorum) en Bustamante, Nuevo Leon, noreste de México. Este es el primer reporte de Scelionidae parasitando huevos de polillas del cactus (Phycitini). Debe investigarse la capaci-dad de esta avispa para parasitar los huevos de C. cactorum.

Interacting host modifier systems control Wolbachia-induced cytoplasmic incompatibility in a haplodiploid mite.

Reproductive parasites such as Wolbachia spread within host populations by inducing cytoplasmic incompatibility (CI). CI occurs when parasite‐modified sperm fertilizes uninfected eggs and is typified by great variation in strength across biological systems. In haplodiploid hosts, CI has different phenotypic outcomes depending on whether the fertilized eggs die or develop into males. Genetic conflict theories predict the evolution of host modulation of CI, which in turn influences the stability of reproductive parasitism. However, despite the ubiquity of CI‐inducing parasites in nature, there is scarce evidence for intraspecific host modulation of CI strength and phenotype. Here, we tested for intraspecific host modulation of Wolbachia‐induced CI in haplodiploid Tetranychus urticae mites. Using a single CI‐inducing Wolbachia variant and mitochondrion, a nuclear panel was created that consisted of infected and cured near‐isogenic lines. We performed a highly replicated age‐synchronized full diallel cross composed of incompatible and compatible control crosses. We uncovered host modifier systems that cause striking variation in CI strength when carried by infected T. urticae males. We observed a continuum of CI phenotypes in our crosses and identified strong intraspecific female modulation of the CI phenotype. Crosses established a recessive genetic basis for the maternal effect and were consistent with polygenic Mendelian inheritance. Both male and female modulation interacted with the genotype of the mating partner. Our findings identify spermatogenesis as an important target of selection for host modulation of CI strength and underscore the importance of maternal genetic effects for the CI phenotype. Our findings reveal that intraspecific host modulation of CI is underpinned by complex genetic architectures and confirm that the evolution of reproductive parasitism is contingent on host genetics.

The potential impacts of invasions on native symbionts

Symbionts, including parasites, pathogens, and mutualists, can play important roles in determining whether or not invasions by host species will be successful. Loss of enemies from the native habitat, such as parasites and pathogens, can allow for higher invader fitness in the invaded habitat. The presence of mutualists (e.g., pollinators, seed dispersers, mycorrhizae, and rhizobial bacteria) in the invaded habitat can facilitate invasion success. Although there has been a great deal of research focusing on how invading hosts may benefit from enemy losses or mutualist gains, far less attention has focused on how native symbiont populations and communities respond to invasion by non‐indigenous hosts and symbionts. In this paper, we present a conceptual framework examining how symbionts such as parasites, pathogens, commensals, and mutualists can influence invader success and whether these native symbionts will benefit or decline during invasion. The first major factor in this framework is the competence of the invading host relative to the native hosts. Low‐ or non‐competent hosts that support few if any native symbionts could cause declines in native symbiont taxa. Competent invading hosts could potentially support native parasites, pathogens, commensals, and mutualists, especially if there is a closely related or similar host in the invaded range. These symbionts could inhibit or facilitate invasion or have no discernible effect on the invading host. An understanding of how native symbionts interact with competent versus non‐competent invading hosts as well as various invading symbionts is critical to our understanding of invasion success, its consequences for invaded communities and how native symbionts in these communities will fare in the face of invasion.