Frequency Of Parasitism Research Articles

Ant diversity along elevational gradients in the European Alps: insights for conservation under a changing climate

Due to particular vulnerabilities and environmental constraints, Alpine faunas are exposed to significant threats from climate change. However, baseline diversity and distribution data to monitor the trends of key arthropod groups are often scarce. Ants are highly diversified and key ecological actors across terrestrial ecosystems, including mountain ranges. We investigated ant diversity and distribution in the Southern European Alps to provide detailed data over wide elevational gradients and make a first assessment of potential vulnerabilities in the face of global warming. We detected 40 species from 700 to over 2600 m asl, with progressively less diversity corresponding to higher elevations and lower temperatures. Maximum temperature was weakly related to ant diversity as compared to mean and minimum temperature. In shaping ant diversity, the highest elevation species had wide elevation ranges, consistent with Rapoport’s rule. We documented a fauna characterized by cold-adapted genera, species with wide geographic distributions and presumably high dispersal capabilities, no dietary specializations, and a high frequency of social parasitism. Concerning Bergmann’s rule, average ant species size was not larger in the coldest environments. Red wood ants, characterized by much more populous colonies as compared to the other ant species, had the highest number of ant individuals to be found at intermediate elevations and in woodland habitats. On the other hand, grasslands and shrublands proved to be the most species-rich habitats. Our data lay the groundwork for further investigation on elevational shifts and provide context for the discussion of key aspects of the management and conservation of European alpine ants.Implications for insect conservationThe cold climate of the European Alps has so far protected its ant fauna from the incursion of alien competitors as compared to what is observed in the Mediterranean region. The scarcity of species with restricted distribution ranges or high-elevation specialists, as well as diet specialists, may grant ants of the European Alps more resilience to climate change as compared to other Alpine arthropod groups. On the other hand, many species are highly interconnected by social parasitism relationships that may be vulnerable to ecological cascade effects. While forest habitats host red wood ants, which are often protected for their important ecological role, the importance of grassland must not be overlooked as they support the highest ant species richness.

Alternative mating strategies in Eurasian Reed Warblers: extra-pair paternity and egg dumping

Alternative mating strategies, involving mating outside a social pair bond, have been studied intensively during the last few decades. However, we are still far from understanding what factors affect their frequencies in wild bird populations. In 2006–2011 we studied Eurasian Reed Warblers breeding in the nature reserve “Stawy Milickie” in SW Poland, and analysed the frequency of extra-pair paternity (EPP) and intra-specific brood parasitism (IBP). We genotyped a total of 786 nestlings from 259 nests. EPP offspring constituted 13.40% of all young (from 7.63% to 22.82% in different study years), and they were found in 21.62% of the broods (from 14.6% to 32.7% annually). The mean proportion of females with EPP young was 24.2% (from 16.2 to 41.7% annually). The proportion of EPP young in nests containing any EPP offspring ranged from 25% to 100% (on average 60%) and was not related to brood size. EPP young in one nest were sired usually by one or two males (92% of all cases), but we recorded one brood with three EPP fathers and one brood of four, where each young was sired by a different EPP male, and none by a social male. We found only one case of intra-specific brood parasitism (IBP). The brood with IBP constituted 0.39% of all examined broods, while the nestling that hatched from the dumped egg constituted 0.13% of all young whose parents were genotyped. We conclude that extra-pair paternity is a relatively common and regularly occurring alternative mating strategy in our study population of Reed Warblers, while intra-specific brood parasitism is extremely rare.

Diversity and prevalence of gastrointestinal parasites of Black Bengal goats in Natore, Bangladesh.

The objective of this work was to estimate the diversity of gastrointestinal (GI) parasite species, their prevalence, and risk factors in Black Bengal goats (BBGs) of Natore, Bangladesh. Fecal samples from randomly selected 260 BBGs were processed through Stoll's ova counting method, floatation, and simple sedimentation method. Microscopy-based identification of parasitic eggs, cysts, or oocysts was made. A semi-structured questionnaire-based data on host and management practices were collected from the owner. Data analysis was done using Statistical Package for Social Sciences. The overall prevalence of GI parasites in BBGs was 65.4%, with an individual prevalence of 8.5% for Fasciola gigantica, 21.5% for Paramphistomum spp., 20% for Haemonchus spp., 34.2% for Strongyloides spp., 8.5% for Trichuris spp., and 9.2% for Eimeria spp. No significant effect of host age, gender, body condition, animal rearing system, or housing floor type was observed on parasitism. Animals of young age, female, poorly body-conditioned, living in a free-range system, and housed on a muddy floor had a relatively higher susceptibility to infection. Deworming had a significant impact on reducing the frequency of caprine GI parasitism. Despite the significant effect of anthelmintic, the elevated prevalence of GI parasites in BBGs suggests a critical need for developing effective strategies to prevent caprine parasitoses.

Brood parasitism of Hooded Warblers by Brown-headed Cowbirds: Severe impact on individual nests but modest consequences for seasonal fecundity and conservation

Abstract Brood parasitism by Brown-headed Cowbirds (Molothrus ater) often has pronounced negative effects on host nests. However, the extent to which parasitism reduces annual reproduction and presents conservation challenges for host species is unclear. We address this issue with data from a color-banded population of Hooded Warblers (Setophaga citrina) in Pennsylvania, where Hooded Warblers have increased dramatically despite frequent nest parasitism. Our analysis is based on both an extensive dataset (8 years, 847 nests) on the per-nest impacts of cowbird parasitism and female-based stochastic simulations that accurately reflect the reproductive biology and parasitism rate (30%) of our study population. Cowbird parasitism has multiple negative consequences for Hooded Warbler nests, including (1) reduced host clutch size; (2) increased nest abandonment; (3) increased risk of complete failure due to predation; and (4) in surviving nests increased egg loss, hatching failure, and nestling mortality. We estimate that parasitism reduces success of Hooded Warbler nests 68%, from 1.29 to 0.41 fledglings per nest. For females and populations, however, the consequences of nest parasitism are considerably less extreme; female annual fecundity decreases 25% for each nesting attempt parasitized, and population-level fecundity drops 5.6% for each 10% increase in the frequency of parasitism. These more modest impacts are attributable to (1) steep declines in rates of cowbird parasitism as the nesting season progresses, (2) rapid renesting following abandonment or failure of parasitized nests, and (3) regular double brooding, with second broods initiated in late June and July when the incidence of cowbird parasitism is low. Our results help resolve the paradox of how cowbird parasitism can have both severe consequences for individual host nests but more modest and sustainable conservation impacts on the seasonal fecundity of females and populations. They further underscore the importance of determining population-level effects of brood parasites before investing in costly management efforts.

Different hosts in different lakes: prevalence and population genetic structure of plerocercoids of Ligula intestinalis (Cestoda) in Czech water bodies.

Ligula intestinalis (Linnaeus, 1758) is a tapeworm parasite with a worldwide distribution that uses a wide variety of fish species as its second intermediate host. In the present study, we investigated the prevalence and population genetic structure of plerocercoids of L. intestinalis in five common cyprinoid species, roach Rutilus rutilus (Linnaeus), freshwater bream Abramis brama (Linnaeus), white bream Blicca bjoerkna (Linnaeus), bleak Alburnus alburnus (Linnaeus), and rudd Scardinius erythrophthalmus (Linnaeus), collected in six water bodies of the Czech Republic (Milada, Most, Medard, Jordán, Římov and Lipno). Of the six study sites, the highest frequency of parasitism was recorded in Lake Medard (15%). The overall prevalence rate among the species was as follows: roach > rudd ≥ freshwater bream > bleak > white bream. Two mitochondrial genes (cytb and COI) were used to compare the population genetic structure of parasite populations using selected samples from the five fish species. The results of the phylogenetic analysis indicated that all populations of L. intestinalis were placed in Clade A, previously identified as the most common in Europe. At a finer scale, haplotype network and PCoA analyses indicated the possible emergence of host specificity of several mtDNA haplotypes to the freshwater bream. Moreover, pairwise Fixation indices (FST) revealed a significant genetic structure between the parasite population in freshwater bream and other host species. Parasite populations in roach not only showed the highest rate of prevalence but also depicted a maximum number of shared haplotypes with populations from bleak and rudd. Our results suggest that recent ecological differentiation might have influenced tapeworm populations at a fine evolutionary scale. Thus, the differences in prevalence between fish host species in different lakes might be influenced not only by the parasite's ecology, but also by its genetic diversity.

Sexual and developmental variations of ecto-parasitism in damselflies.

The prevalence and intensity of parasitism can have different fitness costs between sexes, and across species and developmental stages. This variation could arise because of species specific sexual and developmental differences in body condition, immunity, and resistance. Theory predicts that the prevalence of parasitism will be greater in individuals with poor body condition and the intensity of parasitism will be greater in individuals with larger body size. These predictions have been tested and verified in vertebrates. In insects, however, contradictory evidence has been found in different taxa. Here, we tested these predictions on two species of Agriocnemis (Agriocnemis femina and Agriocnemis pygmaea) damselflies, which are parasitized by Arrenurus water mite ectoparasites. We measured body weight, total body length, abdomen area and thorax area of non-parasitized damselflies and found body condition varied between males and females, between immature females and mature females and between A. femina and A. pygmaea. Then, we calculated the parasite prevalence, i.e., the absence or presence of parasites and intensity, i.e., the number of parasites per infected damselfly in eleven natural populations of both species. In line to our predictions, we observed greater prevalence in immature females than mature females but found no difference in parasite prevalence between males and females. Furthermore, we found that parasite intensity was higher in females than males and in immature females than mature females. Our result also showed that the frequency and intensity of parasitism varied between the two studied species, being higher in A. pygmaea than A. femina. Our study provides evidence that parasitism impacts sexes, developmental stages and species differentially and suggests that variation may occur due to sex, developmental stage, and species-specific resistance and tolerance mechanism.

Parasite‐mediated sexual selection in a damselfly

AbstractSexual selection can improve population fitness and purge deleterious mutation from the gene pool by promoting condition‐dependent mate selection. One ecological factor that reduces individual condition is parasitism. Parasitism tends to increase hosts' mutation load and likely indicates inferior host genetic quality. Parasite‐mediated selection, therefore, should favour the mating success of parasite‐resistant individuals over parasitised individuals. We tested this hypothesis in male Agriocnemis pygmaea damselflies, which are parasitised by Arrenurus water mites. We calculated frequency (i.e. the proportion of parasitism) and intensity (i.e. the number of parasites per parasitised individual) of parasitism in free‐flying males and males in copula in seven natural populations. We predicted that males observed mating will be less likely to be parasitised than expected based on the frequency of parasitism in the population. We further predicted that parasite intensity would be lower in males caught in copula than single males. We found that parasitised males were significantly less likely to be found in copula than non‐parasitised males, independent of their occurrence frequency. However, there was no difference in the average parasite load between males captured in copula or free‐flying males. Our study shows that in addition to natural selection, sexual selection is a strong agent against parasitism and implies that it could promote local adaptation to counteract parasite driven extinction risks.

Detection of Cryptosporidium spp. and Giardia duodenalis in small wild mammals in northeastern Brazil.

This study investigated the occurrence of Giardia duodenalis and Cryptosporidium spp. in rodents and marsupials from the Atlantic Forest in southern Bahia, northeastern Brazil. Two hundred and four fecal samples were collected from different forest areas in the municipalities of Ilhéus, Una, Belmonte, and Mascote. Identifications were performed using PCR and nested PCR followed by sequencing of the gdh and tpi genes for G. duodenalis, and the gp60 and Hsp-70 genes for Cryptosporidium. The total frequency of positive PCR samples for both G. duodenalis and Cryptosporidium spp. was 5.4% (11/204). Giardia duodenalis occurred in 2.94% (4/136) of rodents and 2.94% (2/68) of marsupials. The prevalence of Cryptosporidium in rodents and marsupials was 1.47% (2/136) and 4.41% (3/68), respectively. In the areas sampled, the frequency of parasitism was 50% (7/14), while the Mascote region alone had no parasitized animals. The G. duodenalis subgenotype AI was identified in the rodent species Hylaeamys laticeps, Oecomys catherinae, Oligoryzomys nigripes and Akodon cursor, and in the marsupials Gracilinanus agilis and Monodelphis americana. In the rodents Rhipidomys mastacalis, H. laticeps and in the marsupial Marmosa murina the protozoa Cryptosporidium fayeri, Cryptosporidium parvum and Cryptosporidium ubiquitum with subtypes IIa and IVg by the gp60 gene were found. In conclusion, this study provides the genetic characterization of Giardia and Cryptosporidium species and genotypes in rodents and marsupials. And, these findings reinforce that the rodent and marsupial species mentioned above play a role as new hosts for Giardia and Cryptosporidium.

A comparative study of the structural and mechanical properties of avian eggshells among hosts of obligate brood parasitic cowbirds (genusMolothrus)

AbstractObligate avian brood parasites depend on hosts for parental care, which in turn suffer fitness losses as a result of parasitism. Mechanisms by which brood parasitic cowbirds (Molothrus spp.) reduce host breeding success include the puncture (M. rufoaxillaris and M. bonariensis) or removal (M. ater) of the eggs of the host. Our working hypothesis is that the host eggs’ mechanical strength and their size and shape in species with higher frequency of parasitism covaries with the cowbird’s strategy to reduce host clutch size. Our results, obtained through phylogenetic analyses based on egg 2D geometric morphometry and eggshell mechanical and ultrastructural measurements, suggest that egg-puncturer behaviour has led to an increase in the strength of the host’s eggshell, which might make them more difficult to be pierced. We also characterized larger, more rounded and asymmetrical eggs in frequent hosts of M. ater, which might be more difficult to be removed. These interspecific host egg and shell traits were also positively affected by the frequency of parasitism, indicating that species-specific patterns of parasitic costs select for respective anti-parasitic defences in hosts.

Larval Parasitism of the Silver-Spotted Skipper, Epargyreus clarus (Cramer) (Lepidoptera: Hesperiidae), in the Washington, DC Area

Over a 4-year time span (2013–2016), we collected and reared several thousand larvae of the silver-spotted skipper butterfly, Epargyreus clarus (Cramer), from six different commonly used host plants growing at sites in and around the Washington, DC metropolitan area. Of these, more than 1500 survived to pupation or parasitoid emergence, with annual frequencies of parasitism ranging from 1.7–7.6%. More parasitoids tended to emerge from E. clarus larvae collected later in the season, and parasitism varied significantly among host plants. In total we reared six morphologically distinct species of primary parasitoids (all koinobiont endoparasitoids) from E. clarus larvae; these included four species of Braconidae and a single species each of Ichneumonidae and Tachinidae. The braconid Pneumagathis spiracularis (Muesebeck) is reported as a parasitoid of E. clarus for the first time along with the first host plant associations for P. spiracularis. New host plant associations are reported for the ichneumonid Casinaria lamina (Viereck) parasitic on E. clarus. We also report the trigonalid Orthogonalys pulchella (Cresson) as a parasitoid of P. spiracularis along with new host plant associations; P. spiracularis is the first reported host other than a species of Tachinidae and the second record of a trigonalid parasitic on a species of Braconidae. Images of adult parasitoids are provided, and relevant natural history data are presented based on our careful rearing protocol.

Modeling Climatic Influences on Three Parasitoids of Low-Density Spruce Budworm Populations. Part 2: Meteorus trachynotus (Hymenoptera: Braconidae)

This is the second article of a series of three where we develop temperature-driven models to describe the seasonal interactions between parasitoids and their hosts which we use to explore the impact of climate on their spatiotemporal biology. Here, we model the biology of Meteorus trachynotus (Hymenoptera: Braconidae) with an individual-based model of its daily interactions with two host species. This model predicts the performance of the parasitoid in response to temperature affecting its seasonal development and that of the two hosts. We compare model output with an extensive set of field observations from natural host populations. The predicted activity of the first adult parasitoid generation closely matches the seasonal pattern of attack on the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae) within the limitations of available data. The model predicts 1–4 full generations of M. trachynotus per year in eastern North America, with generations well synchronized with larvae of a known overwintering host, the obliquebanded leafroller Choristoneura rosaceana. The model predicts the observed density dependence of parasitism on spruce budworm. Predicted performance exhibits spatial variation caused by complex life-history interactions, especially synchrony with the overwintering host. This leads to a better performance in warm but not hot environments at middle latitudes and elevations. The model’s predicted spatial patterns correspond closely to our field observations on the frequency of parasitism on spruce budworm. Under climate change, the model predicts that the performance of M. trachynotus populations will improve in the northern portion of its range.

Aquatic larval of the genus Arrenurus (Trombidiformes: Parasitengonina: Arrenuridae) associated with Odonata species from Pampa Biome, Brazil

Abstract: Many studies have reported that the interaction between water mite larvae and their Odonata hosts affects mating success, flight, and longevity. Males and females of Odonata species collected in the steppes and coastal plains (Pampa Biome) of Rio Grande do Sul were analyzed. Mites were removed when present and the prevalence and intensity of parasites was calculated. The aim of this study was to search and report new Odonata hosts species that are parasitized by water mite larvae and also to evaluate the prevalence and intensity rates; the differences in mite occurrence and frequency between males and females, and between thorax and abdomen of the dragonflies and damselflies in the southern Pampa biome located in Rio Grande do Sul. A total of 162 larval mites were found associated to two Odonata families: Coenagrionidae (Acanthagrion lancea Selys, 1876, Ischnura capreolus Hagen, 1861 and Ischnura fluviatilis Selys, 1876) and Libelullidae (Micrathyria ocellata Martin, 1897 and Perithemis mooma Kirby, 1889). All mites were identified as Arrenurus (Arrenurus) sp. (Arrenuridae) and showed high numbers when attached to I. capreolus (55.5%), I. fluviatilis (33.3%), followed by low numbers on M. ocellata (6.1%), A. lancea (3.7%), and P. mooma (1.2%). Mites were found on males and females of I. capreolus and I. fluviatilis, females of A. lancea and P. mooma and in M. ocellata only in males. As the parasitized Odonata species are generalist and abundant in all water body types, traits associated with mating and oviposition or larval behavior are believed to explain the frequency of parasitism in these species.

Brood parasitism leads to zero recruitment in the globally endangered Yellow CardinalGubernatrix cristata

SummaryThe Yellow CardinalGubernatrix cristatais an ‘Endangered’ passerine from southern South America. For the past three years a management plan for Yellow Cardinals has been implemented in Argentina, in which rescued individuals from the illegal cage bird trade were released back into suitable habitats within their population of origin. We studied the reproductive success of a mixed population of released and wild Yellow Cardinals in La Pampa province, Argentina, during the reproductive season of 2019. The population was highly parasitized by the brood parasitic Shiny CowbirdMolothrus bonariensis. The frequency of parasitism was 100% and the intensity of parasitism was 4.5 ± 3.4 (mean ± SD) eggs per parasitized nest (range 1–13). No Yellow Cardinal chicks were recruited in the monitored nests, mainly as a consequence of Shiny Cowbird parasitism. The unusually high rate of parasitism led to a poor outcome of the reintroduction programme and indicates the need to update the conservation actions that have been carried out for the Yellow Cardinal so far. Shiny Cowbird abundance varies within the distribution of Yellow Cardinals, related to habitat modification and farming activities. Thus, further research on habitat suitability and assessment of Shiny Cowbird abundance should be incorporated into future strategies for the conservation of the Yellow Cardinal.

Population- and Species-Based Variation of Webworm-Parasitoid Interactions in Hogweeds (Heracelum spp.) in the Netherlands.

In three Dutch populations of the native small hogweed (Heracleum sphondylium L. [Apiales: Apiaceae]), and one of the invasive giant hogweed (H. mantegazzianum Sommeier & Levier [Apiales: Apiaceae]), interactions between a specialist herbivore, the parsnip webworm (Depressaria radiella), and its associated parasitoids were compared during a single growing season. We found host plant species-related differences in the abundance of moth pupae, the specialist polyembryonic endoparasitoid, Copidosoma sosares, the specialist pupal parasitoid, Barichneumon heracliana, and a potential hyperparasitoid of C. sosares, Tyndaricus scaurus Walker (Hymenoptera: Encyrtidae). Adult D. radiella body mass was similar across the three small hogweed populations, but moths and their pupal parasitoid B. heracliana were smaller when developing on giant than on small hogweeds where the two plants grew in the same locality (Heteren). Mixed-sex and all-male broods of C. sosares were generally bigger than all-female broods. Furthermore, adult female C. sosares were larger than males and adult female mass differed among the three small hogweed populations. The frequency of pupal parasitism and hyperparasitism also varied in the different H. sphondylium populations. These results show that short-term (intra-seasonal) effects of plant population on multitrophic insects are variable among different species in a tightly linked food chain.

Weed Hosts of Field Dodder (Cuscuta campestris Yunck.) in Northwestern Marmara Region of Turkey

Dodder (Cuscuta spp.) is a parasitic weed damaging several crop plants. A weed survey covering vegetable fields, orchards and vineyards was conducted from 2015 to 2018 in Northwestern Turkey. During surveys parasitic weed Cuscuta campestris Yunck was found attached to 23 weed species from 15 families. Higher frequency of parasitism of dodder was determined in Polygonum aviculare L., Amaranthus retroflexus L., Chenopodium album L., Ecballium elaterium (L.) A. Rich., Lactuca serriola L., Portulaca oleracea L. and Cichorium intybus L. weed species. The infection intensity was the highest in Lactuca serriola L., Convolvulus arvensis L., Portulaca oleracea L., Tribulus terrestris L., Ecballium elaterium (L.) A. Rich., Rumex crispus L. and Polygonum aviculare L.

Unsuccessful Host Stinging by Aphelinus asychis (Hymenoptera: Aphelinidae) Impacts Population Parameters of the Pea Aphid (Hemiptera: Aphididae).

The biocontrol values of natural enemies are strongly correlated to their ability to regulate the density of their host/prey. For parasitoids, apart from parasitism and host feeding, unsuccessful host stinging (i.e., stings that were aborted, abandoned, or discontinued without oviposition or host feeding) can also negatively affect their hosts and host populations. Although several studies have reported unsuccessful host stinging and its impacts on hosts, the effects of this type of attack on host life table parameters are still unclear. In the present study, we used the parasitoid Aphelinus asychis Walker (Hymenoptera: Aphelinidae) and its host Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) to investigate the influence of unsuccessful host stinging on host populations under laboratory conditions at. Biological parameters of A. pisum were analyzed using an age stage, two-sex life table. The results of this study showed that unsuccessful host stinging was prevalent under laboratory conditions, and the frequency of this type of attack on third- and fourth-instar hosts was higher than the frequencies of parasitism and host feeding. Unsuccessful host stinging adversely impacted aphid populations, by decreasing aphid survival and reproduction, and impacts were greatest in hosts attacked at the first and fourth instars. These results indicate that unsuccessful host stinging enhances the biological control impact of A. asychis attacking A. pisum, and its effect on host populations should also be considered when selecting and mass rearing of parasitoids for biological control.

Egg rejection behavior does not explain the lack of cowbird parasitism on an eastern North American population of Red-winged Blackbirds

BackgroundRed-winged Blackbirds (Agelaius phoeniceus), hereafter red-wings, are much less frequently parasitized by Brown-headed Cowbirds (Molothrus ater) in eastern North America than in central North America and had not been recorded as hosts in our study area in southeastern Pennsylvania. Although hosts of Old World cuckoos (Cuculidae) often show geographic variation in egg rejection behavior, cowbird hosts typically exhibit uniform responses of all acceptance or all rejection of cowbird eggs. Thus, geographic variation in cowbird parasitism frequencies might reflect a different behavioral response to parasitism by hosts where only some populations reject parasitism. In this study, we tested whether egg rejection behavior may explain the lack of parasitism observed in our eastern red-wing population, which may provide insight into low parasitism levels across eastern North America.MethodsWe parasitized red-wing nests with model cowbird eggs to determine their response to parasitism. Nests were tested across three nest stages and compared to control nests with no manipulations. Because rejection differed significantly by stage, we compared responses separately for each nest stage. We also monitored other songbird nests to identify parasitism frequencies on all potential hosts.ResultsRed-wings showed significantly more rejections during the building stage, but not for the laying and incubation stages. Rejections during nest building involved mostly egg burials, which likely represent a continuation of the nest building process rather than true rejection of the cowbird egg. Excluding these responses, red-wings rejected 15% of cowbird eggs, which is similar to rejection levels from other studies and populations. The overall parasitism frequency on 11 species surveyed in our study area was only 7.4%.ConclusionsEgg rejection behavior does not explain the lack of parasitism on red-wings in our eastern population. Alternatively, we suggest that cowbird preference for other hosts and the low abundance of cowbirds in the east might explain the lack of parasitism. Future research should also explore cowbird and host density and the makeup of the host community to explain the low levels of parasitism on red-wings across eastern North America because egg rejection alone is unlikely to explain this broad geographic trend.

Ant–hemipteran association decreases parasitism of Phenacoccus solenopsis by endoparasitoid Aenasius bambawalei

1. Mutualism between ants and honeydew‐excreting hemipterans is ubiquitous in the ecosystem. It is widely accepted that ant tending facilitates the colony growth of hemipterans by protecting them from predators and parasitoids. However, few studies have explored how ant tending helps defend against natural enemies.2. Ghost ant Tapinoma melanocephalum and the invasive mealybug Phenacoccus solenopsis have a close mutual relationship. Previous studies have shown that ghost ant tending can definitely reduce parasitism and visit frequency of Aenasius bambawalei, the dominant endoparasitoid of P. solenopsis. However, the ghost ant workers seldom attack the parasitoids. It is still unclear how the ghost ant adversely affects parasitoids. This study explored the mechanism underlying the impacts of ants on natural enemies of the mealybugs.3. Honeydew produced by P. solenopsis was an attractant to A. bambawalei. Parasitoids exhibited less searching activity, shorter longevity and lower parasitism when supplied with less honeydew. Aenasius bambawalei showed significant avoidance of pygidial gland secretions and visual cues of ghost ants. Parasitism in plants treated with 6‐methyl‐5‐hepten‐2‐one, actinidine, and gland extracts was significantly lower than that in plants treated only with solvents (paraffin oil or double‐distilled water).4. It is concluded that honeydew consumption by ghost ants could negatively influence the performance of parasitoids. The pygidial gland secretions and visual cues of ghost ants also significantly inhibit the parasitism. These results may contribute to a better understanding of the regulation mechanism in ant–hemipteran–enemy interactions.

Parasitism of Rainbow Trout in Hatchery Raceways by Chestnut Lampreys

AbstractOther than anecdotal evidence, parasitism of trout by lampreys in hatcheries has not been characterized. This study investigated the frequency of parasitism on Rainbow Trout Oncorhynchus mykiss by presumptive Chestnut Lampreys Ichthyomyzon castaneus in the raceways of Norfork National Fish Hatchery (northern Arkansas) from January to April 2013. Although no Chestnut Lampreys were collected, 82 wounded trout were identified from 23 of the 54 raceways sampled, with frequencies of parasitism being greatest during April. We also examined attachment site selection; 95% of attachments were dorsal, and most were in the mid‐section of the host fish. Data indicating preference for a dorsal attachment site selection are consistent with observations generated in most studies of Chestnut Lampreys. Although not significant in terms of trout lost to parasitism, efforts should be maintained to minimize lamprey invasion into hatcheries, as the zoonotic transfer of pathogens has been documented in other lampreys.

Криптоспоридіоз собак: особливості перебігу та лікування

The article presents the results of studies of the cryptosporidiosis course in dogs and the effectiveness of specific treatment of sick animals. It is established that gastroenteritis of dogs take the leading place among all internal diseases of animals. Often, diagnosis is based on clinical signs, and laboratory blood tests reflect the picture of metabolic processes in the body and determine the degree of effectiveness of certain organs. Unfortunately, a comprehensive examination to identify all the factors of the disease is extremely rare. Conducting of coprologic studies in the system of comprehensive examination opens up additional opportunities for assessing the activity of the gastrointestinal tract. Definition of the coprogram allows you to find out the state of functioning of individual departments of the gastrointestinal tract. Evaluation of the parasitofauna of the gastrointestinal tract also plays an extremely important role, allowing to determine the degree of influence of its representatives on the pathogenesis of gastroenteritis. Participation of parasites as etiological factors for gastroenteritis in dogs studied enough, especially for certain ecological and epizootic conditions. Given the information about the possibility of resident stay of cryptosporidium in the intestines of dogs, there was a need to study their role in the occurrence of disorders of the gastrointestinal tract of animals. In the structure of etiological factors, cryptosporidiosis-enteral protozoosis caused by intracellular parasites sporozoa and take up to 40%. It was determined that the causative agent is Cryptosporidium parvum , which is widespread and has a very wide species specificity. The main age group with a clinically pronounced course is young at the age of 3–12 months. Disease is inherent in the seasonal distribution – often seen in summer and virtually not recorded in winter. Clinical signs in dogs, patients with cryptosporidiosis were characterized by a pronounced gastroenteritis. Among the specific features is a watery diarrhea of greenish color, with an unpleasant odor and an admixture of mucus and blood veins. Coprological studies showed significant intensity of infestation. Analyzing the obtained laboratory picture, we have established a tendency to anemia, leukocytosis, increased erythrocyte sedimentation rate. Such indicators are a sample of the inflammatory process, which is systemic in nature and is reflected in such parameters of the hematological profile. Erythrocyte sedimentation rate is an indicator of redistribution of protein fractions of blood serum towards globulin. This is also confirmed by biochemical studies. Thus, against the background of the tendency to hypoproteinemia, there is a significant hypoalbuminemia and a tendency to an increase in globulin fraction proteins. The shift in the albumin-globulin ratio also indicates a state of inflammation in the body, a violation of the liver and pancreas. Indicators of the hepatobiliary system is the level of bilirubin pigment and the activity of serum transaminases. Our studies revealed significant hyperbilirubinemia with a significant increase in the level of conjugated bilirubin. Such indicators determine the malfunction of hepatocytes, which reduces the elimination of bilirubin, and certify the process of organic changes in the hepatobiliary system. The activity of transaminases of blood serum also confirms the defeat of the liver parenchyma. The most important and sensitive is the indicator of the activity gammaglutamyltranspeptidase (GGT). Thus, it can be argued about the development of reactive hepatitis. A significant significant increase in ALT and AST activity further confirms this position. We noted a significant increase in the activity of pancreatic enzymes – α-amylase and lipase, which indicates the development of acute-subacute pancreatitis. The increase in creatinine levels is tendentious, but urea levels are significantly increased. This range of indicators of nitrogen metabolism prefers liver damage, in which urea is not able to fully metabolize. Thus, the laboratory tests revealed the development of systemic inflammatory response, functional and organic disorders of the hepatobiliary system and pancreas, which were manifested by reactive hepatitis and acute-subacute pancreatitis. According to the study of the coprogram, the insufficiency of the small intestine digestion, violation of the enzymatic functions of the pancreas, biliary and biliary functions were also established. For specific treatment sick dogs highly effective it turned out the use of drug Brovaseptol in the form of injections according to instructions. After the course of treatment, its intensity was 100%. The results of the study of the efficacy of the drug Brovaseptol® showed its high anti-cryptosporidiosis effect. Given that the animals are well tolerated the drug and adverse reactions have not been identified, we can recommend the use of funds to combat cryptosporidiosis. You also need to pay attention to the fact that the relatively high frequency of parasitism of Cryptosporidium oocysts in young dogs and the presence of other protozoa in the composition pause determines the possibility of using the drug Browsepoll treatment of animals suffering from gastroenteritis of unknown etiology.