Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 75
Filter
Add more filters

Publication year range
1.
Parasitol Res ; 120(7): 2333-2342, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33956214

ABSTRACT

The costs parasites impose on hosts can lead to reductions in survival and fecundity, but few studies have evaluated the impacts after infection. Hairworms are parasites of terrestrial arthropods that are free-living in aquatic systems as adults. As parasitic juveniles, hairworms acquire nutrients from their definitive hosts, shifting resources away from host development to parasite growth. However, until now, only one study has examined survivorship of naturally infected hosts with hairworms. Using a different hairworm and host system, we conducted experimental infections to examine growth, survivorship, and egg production in virgin female Acheta domesticus infected with the hairworm, Paragordius varius. We found that infected crickets grew significantly less during hairworm development compared to sham-infected control crickets. After releasing their worms, infected crickets survived for 73 ± 32 days but had significantly shorter life spans by an average of 13 days compared to sham-infected control crickets. However, we found that 50% of previously infected crickets produced eggs after releasing their worms. Taken together, these observations suggest that female crickets infected with hairworms may experience less mortality than previous anecdotal evidence suggests. Finally, we discuss the definition of parasitoid and how it relates to nematomorphs, and we suggest that more field and laboratory research is required before suggesting hairworms are parasitoids.


Subject(s)
Gryllidae/physiology , Gryllidae/parasitology , Helminths/physiology , Animals , Female , Fertility , Gryllidae/growth & development , Helminths/growth & development , Linear Models , Longevity , Male , Oogenesis
2.
J Invertebr Pathol ; 160: 54-60, 2019 01.
Article in English | MEDLINE | ID: mdl-30528638

ABSTRACT

The entomopathogenic nematode, Steinernema scapterisci, a specialist parasite of crickets, has been successfully used to combat the southern mole cricket, Neoscapteriscus borellii, which is an invasive pest of turf grass. As an entomopathogenic nematode, S. scapterisci causes rapid death of the insects it infects and uses bacteria to facilitate its parasitism. However, our understanding of the relative contributions of the nematode, S. scapterisci, and its bacterial symbiont, Xenorhabdus innexi, to parasitism remains limited. Here we utilized the sand cricket, Gryllus firmus, as a model host to evaluate the contributions of the EPNs S. scapterisci and S. carpocapsae, as well as their symbiotic bacteria, X. innexi and X. nematophila, respectively, to the virulence of the nematode-bacterial complex. We found that G. firmus has reduced susceptibility to infection from both S. scapterisci and the closely related generalist parasite S. carpocapsae, but that S. scapterisci is much more virulent than S. carpocapsae. Further, we found that N. borellii has reduced susceptibility to X. nematophila, and that G. firmus has reduced susceptibility to X. nematophila, X. innexi, and Serratia marcescens, much more so than other insects that have been studied. We found that the reduced susceptibility of G. firmus to bacterial infection is dependent on development, with adults being less susceptible to infection than nymphs. Our data provide evidence that unlike other EPNs, the virulence of S. scapterisci to crickets is dependent on the nematode rather than the bacterial symbiont that it carries and we speculate that S. scapterisci may be evolving independence from X. innexi.


Subject(s)
Bacterial Infections/parasitology , Gryllidae/parasitology , Nematode Infections , Rhabditida/pathogenicity , Xenorhabdus/pathogenicity , Animals , Biological Control Agents , Disease Susceptibility/parasitology , Gryllidae/microbiology , Nematode Infections/parasitology , Serratia/pathogenicity , Virulence
3.
An Acad Bras Cienc ; 91(2): e20180408, 2019 Jun 19.
Article in English | MEDLINE | ID: mdl-31241698

ABSTRACT

Oxyurid nematodes parasitizing the mole cricket Neoscapteriscus vicinus were isolated in the framework of sampling fields of mole-crickets from the pampean region, in Argentina. In this work, molecular characterization of the 18S rRNA partial sequence of nematodes belonging to the families Thelastomatidae (Cameronia arecoensis Marchissio and Miralles 1987) and Travassosinematidae (Binema korsakowi Sergiev 1923 and Binema klossae, Marchissio and Miralles 1993) were carried out. This is the first world report of sequences belonging to B. klossae and C. arecoensis and first Argentinian report of B. korsakowi sequence. Also, morphological and morphometric features of B. klossae, B. korsakowi and C. arecoensis from Argentinian populations are reported.


Subject(s)
Gryllidae/parasitology , Oxyurida/genetics , RNA, Ribosomal, 18S/genetics , Animals , Argentina , Female , Gryllidae/classification , Male , Oxyurida/classification , Oxyurida/isolation & purification
4.
Parasitol Res ; 117(3): 819-823, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29372319

ABSTRACT

To determine potential intermediate hosts of Oxyspirura petrowi, a common nematode eyeworm of wild gallinaceous birds, various arthropod species including red harvester ants, beetles, wood cockroaches, crickets, grasshoppers, katydids, and desert termites were screened for the presence of O. petrowi using specific polymerase chain reaction (PCR) primers targeting the internal transcribed spacer 2 region (ITS2) of the eyeworm ribosomal deoxyribonucleic acid (rDNA). This is the first study to investigate the intermediate hosts of O. petrowi utilizing molecular techniques. We determined 38% (13/34) of the cockroaches, 27% (3/11) of the crickets, and 23% (68/289) of the grasshoppers which were positive for O. petrowi. Identifying potential intermediate hosts of O. petrowi is essential to better understanding the epizoology of the eyeworm's transmission mechanics and to controlling infections in wild gallinaceous birds.


Subject(s)
Arthropods/parasitology , Thelazioidea/isolation & purification , Animals , Bird Diseases/parasitology , Birds/parasitology , Cockroaches/parasitology , DNA, Ribosomal Spacer/genetics , Grasshoppers/parasitology , Gryllidae/parasitology , Larva , Molecular Typing , Oklahoma , Polymerase Chain Reaction , Texas , Thelazioidea/classification , Thelazioidea/genetics
5.
Am Nat ; 185(4): 469-90, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25811083

ABSTRACT

Alternative reproductive tactics may arise when natural enemies use sexual signals to locate the signaler. In field crickets, elevated costs to male calling due to acoustically orienting parasitoid flies create opportunity for an alternative tactic, satellite behavior, where noncalling males intercept females attracted to callers. Although the caller-satellite system in crickets that risk detection by parasitoids resembles distinct behavioral phenotypes, a male's propensity to behave as caller or satellite can be a continuously variable trait over several temporal scales, and an individual may pursue alternate tactics at different times. We modeled a caller-satellite-parasitoid system as a spatially explicit interaction among male and female crickets using individual-based simulation. Males varied in their propensity to call versus behave as a satellite from one night to the next. We varied mortality, density, sex ratio, and female mating behavior, and recorded lifetime number of mates as a function of a male's probability of calling (vs. acting as a satellite) along a gradient in parasitism risk. Frequently, the optimal behavior switched abruptly from being pure caller (call every night) to pure satellite (never call) as parasitism rate increased. However, mixed strategies prevailed even with high parasitism risk under conditions of higher background mortality rate, decreasing density, increasing female-biased sex ratio, and increasing female choosiness. In natural populations, high parasitoid pressure alone would be unlikely to yield fixation of pure satellite behavior.


Subject(s)
Gryllidae/physiology , Adaptation, Physiological , Animal Communication , Animals , Computer Simulation , Diptera/physiology , Female , Gryllidae/parasitology , Male , Sex Ratio , Sexual Behavior, Animal , Vocalization, Animal
6.
Proc Natl Acad Sci U S A ; 109(35): E2324-33, 2012 Aug 28.
Article in English | MEDLINE | ID: mdl-22851767

ABSTRACT

Many parasitic nematodes actively seek out hosts in which to complete their lifecycles. Olfaction is thought to play an important role in the host-seeking process, with parasites following a chemical trail toward host-associated odors. However, little is known about the olfactory cues that attract parasitic nematodes to hosts or the behavioral responses these cues elicit. Moreover, what little is known focuses on easily obtainable laboratory hosts rather than on natural or other ecologically relevant hosts. Here we investigate the olfactory responses of six diverse species of entomopathogenic nematodes (EPNs) to seven ecologically relevant potential invertebrate hosts, including one known natural host and other potential hosts collected from the environment. We show that EPNs respond differentially to the odor blends emitted by live potential hosts as well as to individual host-derived odorants. In addition, we show that EPNs use the universal host cue CO(2) as well as host-specific odorants for host location, but the relative importance of CO(2) versus host-specific odorants varies for different parasite-host combinations and for different host-seeking behaviors. We also identified host-derived odorants by gas chromatography-mass spectrometry and found that many of these odorants stimulate host-seeking behaviors in a species-specific manner. Taken together, our results demonstrate that parasitic nematodes have evolved specialized olfactory systems that likely contribute to appropriate host selection.


Subject(s)
Gastropoda/parasitology , Gryllidae/parasitology , Host-Parasite Interactions/physiology , Nematoda/physiology , Nematode Infections/physiopathology , Smell/physiology , Acetoin/pharmacology , Aldehydes/pharmacology , Animals , Behavior, Animal/drug effects , Behavior, Animal/physiology , Calcium Compounds/pharmacology , Carbon Dioxide/pharmacology , Chemotaxis/drug effects , Chlorobenzenes/pharmacology , Cresols/pharmacology , Cyclohexane Monoterpenes , Monoterpenes/pharmacology , Nematoda/pathogenicity , Odorants , Oxides/pharmacology , Sodium Hydroxide/pharmacology , Virulence
7.
Commun Agric Appl Biol Sci ; 79(2): 331-4, 2014.
Article in English | MEDLINE | ID: mdl-26084111

ABSTRACT

Common European mole cricket (CEML) Grillotalpa grillotalpa L causes damage to field, vegetable crops, and small fruits growing at commercial plantations and nurseries. Chemical control if insecticides are used in poison bates, soil application or seedling/bulbs treatment is not environmentally friendly. Inundative and innoculative release of CTVL biocontrol agents, in particularly, Entomopathogenic nematode is a reliable alternative to chemical control. At the laboratory study the comparison of the ability of commercial strain (Nemastar) and local Ukrainian isolate of Steinernema carpocapsae in various concentrations to parasite in last instar nymph and adults of G. grillotalpa was investigated. Grillotalpa grillotalpa was found as a susceptible host for both commercial and local strains of S. carpocapsae. The life cycle of S. carpocapsae both strains in the adults of G. grillotapla with concentration 50 IJs per larva has been completed 12-15 days at t=25 C. Two generations of S. carpocapsae were able to develop in mole cricket for both strains. Two strains of S. carpocapsae nematode species tested were pathogenic to adults of G. grillotalpa. The mortalities of G. grillotapla last last instars' larva caused by S. carpocapsae were recorded in every concentration tested at least 20 to 150 IJs per larva. Mean larval mortality ranged from 48% to 95% depending upon nematode strain and rate of application. Larval mortality generally increased with increasing of nematode rates. It was significant for both S. carpocapsae strains (Ukr. Isolate F = 26 > 2,86) and commercial strain (Nemastar F = 102,95 > 2,86). Ukrainian local isolate caused a greater percentage of mortality of G. grillotapla adult than commercial strain of S. carpocapsae tested but interactions between nematode strains, application rates were not significant. This study presents new data on effect of S. carpocapsae isolated for Ukraine to key agricultural polyphagous pest G. grillotalpa susceptibility screening under controlled conditions, as presented in this paper is the first step towards the development of a biological control program of G. grillotaplpa by using of entomopathogenic nematodes.


Subject(s)
Gryllidae/parasitology , Pest Control, Biological/methods , Rhabditida/pathogenicity , Animals , Female , Gryllidae/physiology , Male , Rhabditida/growth & development , Rhabditida/physiology , Ukraine , Virulence
8.
Mol Ecol ; 22(1): 239-48, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23110593

ABSTRACT

Parasite transmission is determined by the rate of contact between a susceptible host and an infective stage and susceptibility to infection given an exposure event. Attempts to measure levels of variation in exposure in natural populations can be especially challenging. The level of exposure to a major class of parasites, trophically transmitted parasites, can be estimated by investigating the host's feeding behaviour. Since the parasites rely on the ingestion of infective intermediate hosts for transmission, the potential for exposure to infection is inherently linked to the definitive host's feeding ecology. Here, we combined epidemiological data and molecular analyses (polymerase chain reaction) of the diet of the definitive host, the white-footed mouse (Peromyscus leucopus), to investigate temporal and individual heterogeneities in exposure to infection. Our results show that the consumption of cricket intermediate hosts accounted for much of the variation in infection; mice that had consumed crickets were four times more likely to become infected than animals that tested negative for cricket DNA. In particular, pregnant female hosts were three times more likely to consume crickets, which corresponded to a threefold increase in infection compared with nonpregnant females. Interestingly, males in breeding condition had a higher rate of infection even though breeding males were just as likely to test positive for cricket consumption as nonbreeding males. These results suggest that while heterogeneity in host diet served as a strong predictor of exposure risk, differential susceptibility to infection may also play a key role, particularly among male hosts. By combining PCR analyses with epidemiological data, we revealed temporal variation in exposure through prey consumption and identified potentially important individual heterogeneities in parasite transmission.


Subject(s)
Diet , Gryllidae/parasitology , Helminthiasis, Animal/transmission , Peromyscus/parasitology , Predatory Behavior , Animals , Female , Intestinal Diseases, Parasitic/transmission , Male , Polymerase Chain Reaction , Pregnancy , Time Factors
9.
Biol Lett ; 9(1): 20121002, 2013 Feb 23.
Article in English | MEDLINE | ID: mdl-23234864

ABSTRACT

Females prefer dominant males as mating partners in numerous species. Male dominance rank is considered as an honest signal of male quality, because only healthy males in good condition are thought to be able to win fights with other males. Here, we tested whether activation of the immune system influences the success of males in male-male competition and mating in the field cricket, Gryllus integer. We activated the immune system of males with a nylon monofilament (to mimic a parasitoid larva), and arranged fights between male pairs to assess male dominance and associated mating success. Activation of the immune system with nylon monofilament substantially enhanced the fighting success of males during male-male competition but had no effect on mating success. However, sham-manipulation (a wound only) did not have any effect on fighting success although females mated more often with dominant males. Our study suggests that when male crickets meet an apparent survival threat they may behave more dominantly, probably owing to terminal investment. Male success during male-male competition is not always an honest signal of males' quality, but females may be able to detect this dishonesty.


Subject(s)
Animal Communication , Gryllidae/physiology , Gryllidae/parasitology , Mating Preference, Animal , Animals , Competitive Behavior , Female , Gryllidae/immunology , Male , Social Dominance
10.
Ecol Lett ; 15(8): 786-93, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22583960

ABSTRACT

Nematomorph parasites manipulate crickets to enter streams where the parasites reproduce. These manipulated crickets become a substantial food subsidy for stream fishes. We used a field experiment to investigate how this subsidy affects the stream community and ecosystem function. When crickets were available, predatory fish ate fewer benthic invertebrates. The resulting release of the benthic invertebrate community from fish predation indirectly decreased the biomass of benthic algae and slightly increased leaf break-down rate. This is the first experimental demonstration that host manipulation by a parasite can reorganise a community and alter ecosystem function. Nematomorphs are common, and many other parasites have dramatic effects on host phenotypes, suggesting that similar effects of parasites on ecosystems might be widespread.


Subject(s)
Food Chain , Gryllidae/parasitology , Helminthiasis, Animal , Helminths/parasitology , Animals , Behavior, Animal , Biomass , Ecosystem , Fishes , Invertebrates , Population Dynamics , Predatory Behavior , Rivers
11.
Nature ; 440(7085): 756, 2006 Apr 06.
Article in English | MEDLINE | ID: mdl-16598248

ABSTRACT

As prisoners in their living habitat, parasites should be vulnerable to destruction by the predators of their hosts. But we show here that the parasitic gordian worm Paragordius tricuspidatus is able to escape not only from its insect host after ingestion by a fish or frog but also from the digestive tract of the predator. This remarkable tactic enables the worm to continue its life cycle.


Subject(s)
Eating/physiology , Fishes/physiology , Gryllidae/physiology , Gryllidae/parasitology , Parasites/physiology , Predatory Behavior/physiology , Ranidae/physiology , Animals , Fishes/anatomy & histology , Host-Parasite Interactions , Motor Activity/physiology , Parasites/pathogenicity , Ranidae/anatomy & histology , Time Factors , Virulence
12.
Parasitol Res ; 110(1): 483-7, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21766236

ABSTRACT

The aim of this study is to experimentally verify the intermediate host of a common gastrointestinal nematode, Pterygodermatites peromysci, infecting the white-footed mouse (Peromyscus leucopus) and describe the complex life cycle. As with other nematodes in the family Rictulariidae, adult worms reside in the small intestine of the host, and infective eggs are shed into the environment where they are ingested by scavenger insects. A field survey of common nocturnal insects on the forest floors of central Pennsylvania was conducted to identify the putative intermediate host. Encysted nematode larvae were recovered from the hemocoel of three species of camel cricket, Ceuthophilus pallidipes, Ceuthophilus guttulosus, and Ceuthophilus gracilipes. The mean prevalence of infection was 11-17%, and the intensity of infection ranged from 1 to 41 cysts per cricket. Laboratory white-footed mice were infected with cysts harvested from the three species of crickets. Cysts taken from the C. pallidipes produced the highest level of infection (41%); the adult worms recovered from the mice were confirmed as P. peromysci. Laboratory infections of naive C. pallidipes with P. peromysci eggs yielded a 70% infection rate, further verifying that the cricket C. pallidipes is a suitable intermediate host for P. peromysci. We discuss the importance of identifying the intermediate host for understanding the transmission dynamics of a trophically transmitted parasite.


Subject(s)
Life Cycle Stages , Nematoda/growth & development , Peromyscus/parasitology , Animals , Gryllidae/parasitology , Intestine, Small/parasitology , Mice , Nematoda/pathogenicity , Pennsylvania
13.
Nat Commun ; 12(1): 797, 2021 02 04.
Article in English | MEDLINE | ID: mdl-33542210

ABSTRACT

Inadvertent cues can be refined into signals through coevolution between signalers and receivers, yet the earliest steps in this process remain elusive. In Hawaiian populations of the Pacific field cricket, a new morph producing a novel and incredibly variable song (purring) has spread across islands. Here we characterize the current sexual and natural selection landscape acting on the novel signal by (1) determining fitness advantages of purring through attraction to mates and protection from a prominent deadly natural enemy, and (2) testing alternative hypotheses about the strength and form of selection acting on the novel signal. In field studies, female crickets respond positively to purrs, but eavesdropping parasitoid flies do not, suggesting purring may allow private communication among crickets. Contrary to the sensory bias and preference for novelty hypotheses, preference functions (selective pressure) are nearly flat, driven by extreme inter-individual variation in function shape. Our study offers a rare empirical test of the roles of natural and sexual selection in the earliest stages of signal evolution.


Subject(s)
Gryllidae/physiology , Mating Preference, Animal/physiology , Selection, Genetic/physiology , Vocalization, Animal/physiology , Animals , Diptera/physiology , Female , Genetic Fitness , Gryllidae/parasitology , Hawaii , Male , Wings, Animal/physiology
14.
J Helminthol ; 84(4): 369-74, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20132587

ABSTRACT

Gongylonema ingluvicola and Spirocerca lupi are spirurid nematodes that require arthropod intermediate hosts in order to complete their life cycle. Beetles of the family Scarabaeidae are reported to serve as intermediate hosts for both these parasites. In this study selected species of beetles of the family Scarabaeidae as well as other groups of arthropods were screened for susceptibility to infection with S. lupi and G. ingluvicola. Arthropods were exposed to infective eggs of both parasites for a determined period of time and dissected/digested to determine the presence or absence of pre-infective and infective larvae. All the five species of dung beetles exposed to infection with S. lupi, namely, Pachylomerus femoralis, Scarabaeus rugosus, Gymnopleurus humanus, Kheper nigroaeneus and Anachalcos convexus were susceptible and, of the two species exposed to G. ingluvicola, only Gy. humanus was susceptible. Spirocerca lupi eggs developed in millipede species, Daratoagonus cristulatus, and remained as encysted larvae, while in Orthoporoides kyrhocephalus no development was observed. Spirocerca lupi larvae were not detected in the cricket species Gryllus assimilis, or the cockroach species Periplaneta americana, and, similarly, G. ingluvicola larvae were not detected in the millipede species O. kyrhocephalus. The difference in the susceptibility of the arthropods to the two parasite species may depend on their feeding biology.


Subject(s)
Arthropods/parasitology , Host-Parasite Interactions , Spiruroidea/pathogenicity , Thelazioidea/pathogenicity , Animals , Arthropods/classification , Cockroaches/parasitology , Coleoptera/parasitology , Gryllidae/parasitology , Larva/pathogenicity , South Africa , Species Specificity , Spiruroidea/classification , Thelazioidea/classification , Thelazioidea/growth & development , Thelazioidea/isolation & purification
15.
J Parasitol ; 106(1): 46-52, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31990623

ABSTRACT

Recently, the heteroxenous eyeworm, Oxyspirura petrowi, has gained attention due to its prevalence in the declining game bird, Northern bobwhite (Colinus virginianus), but the intermediate hosts of many nematodes remain unknown. However, identifying the intermediate host of O. petrowi with traditional techniques would be difficult and time-consuming, especially considering there are more than 80 potential orthopteran hosts just in Texas. To screen a large number of samples quickly and effectively, primers for nested PCR (nPCR) were developed using the internal transcribed spacer 1 (ITS1) region. Then the nPCR was used to identify which of the 35 species collected from the Order Orthoptera were potential intermediate hosts of O. petrowi. With this technique, 18 potential intermediate hosts were identified. Later, we collected live specimens of species that tested positive to confirm the presence of larvae, but larvae were not found in the live specimens, nor in the extra tissue of the species that had tested positive for O. petrowi DNA. Despite this, this study demonstrated that nPCR is more sensitive than traditional techniques and can be a valuable tool in determining the intermediate hosts of parasites.


Subject(s)
Bird Diseases/transmission , Insect Vectors/parasitology , Orthoptera/parasitology , Spirurida Infections/veterinary , Thelazioidea/genetics , Animals , Base Sequence , Bird Diseases/parasitology , Colinus/parasitology , DNA, Helminth/chemistry , DNA, Helminth/isolation & purification , Grasshoppers/classification , Grasshoppers/genetics , Grasshoppers/parasitology , Gryllidae/classification , Gryllidae/genetics , Gryllidae/parasitology , Larva/classification , Larva/genetics , Orthoptera/classification , Orthoptera/genetics , Polymerase Chain Reaction , Spirurida Infections/parasitology , Spirurida Infections/transmission , Thelazioidea/classification , Thelazioidea/isolation & purification
16.
Science ; 258(5085): 1135-7, 1992 Nov 13.
Article in English | MEDLINE | ID: mdl-1439820

ABSTRACT

Parasitism is a widespread and diverse life strategy that connects species throughout the animal kingdom. Female parasitoid flies of the genus Ormia must find a specific cricket host on which to deposit their parasitic maggots. To reproduce, female flies must perform the same task as female crickets: find a singing male cricket. These flies have evolved a unique hearing organ that allows them to detect and locate singing male crickets. Through evolutionary convergence, these flies possess a hearing organ that much more resembles a cricket's ear than a typical fly's ear, allowing these parasitoids to take advantage of the sensory ecological niche of their host.


Subject(s)
Biological Evolution , Diptera/physiology , Gryllidae/parasitology , Hearing , Acoustic Stimulation , Animals , Diptera/anatomy & histology , Ear/anatomy & histology , Female , Male , Sex Characteristics , Sound , Vocalization, Animal
17.
J Exp Biol ; 212(Pt 24): 4056-64, 2009 Dec.
Article in English | MEDLINE | ID: mdl-19946084

ABSTRACT

In the obligatory reproductive dependence of a parasite on its host, the parasite must trade the benefit of 'outsourcing' functions like reproduction for the risk of assuming hazards associated with the host. In the present study, we report behavioral adaptations of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females home in on the male cricket's songs and deposit larvae, which burrow into the cricket, feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in search of hosts are subject to bat predation, in much the same way as female crickets are when responding to male song. We show that Ormia has evolved the same evasive behavior as have crickets: an acoustic startle response to bat-like ultrasound that manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp response boundary between the frequencies of song and bat cries, resembling categorical perception first described in the context of human speech.


Subject(s)
Acoustics , Diptera/physiology , Gryllidae/growth & development , Gryllidae/parasitology , Life Cycle Stages/physiology , Parasites/physiology , Reflex, Startle/physiology , Animals , Auditory Perception/physiology , Female , Flight, Animal/physiology , Male , Ultrasonics , Vocalization, Animal/physiology , Walking/physiology
18.
Parasitology ; 136(2): 211-8, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19102794

ABSTRACT

SUMMARY: Extreme variation in reproductive success (VRS) has been reported as a common feature of populations. Few individuals producing most of the offspring for the next generation has potential consequences for the population dynamics, genetics, and evolution of a group of organisms. High VRS has been described as a normal feature of helminth populations, although studies have focused largely on parasites of vertebrate hosts. Paragordius varius, a parasite of crickets, was used as a model system to study VRS. In this life cycle, worms absorb and store resources for reproduction from their hosts before being released into water. Egg output varied significantly with worm length, indicating that female length is an excellent predictor of fecundity. Analyses using the Lorenz curve and Gini coefficient suggest that there were no marked fecundity differences. This result was supported by data collected from a natural gordiid population, Gordius difficilis, suggesting that within gordiid populations the offspring of the next generation are contributed nearly equally by females. In addition, male body length appeared to be limited by intensity, whereas females showed no length limitation by crowding. These results contrast previous studies of parasites.


Subject(s)
Helminths/physiology , Animals , Crowding , Female , Fertility , Gryllidae/parasitology , Helminths/anatomy & histology , Male , Population Density , Reproduction
19.
Parasit Vectors ; 12(1): 555, 2019 Nov 21.
Article in English | MEDLINE | ID: mdl-31752968

ABSTRACT

BACKGROUND: Oxyspirura petrowi (Spirurida: Thelaziidae), a heteroxenous nematode of birds across the USA, may play a role in the decline of the northern bobwhite (Colinus virginianus) in the Rolling Plains Ecoregion of West Texas. Previous molecular studies suggest that crickets, grasshoppers and cockroaches serve as potential intermediate hosts of O. petrowi, although a complete study on the life-cycle of this nematode has not been conducted thus far. Consequently, this study aims to improve our understanding of the O. petrowi life-cycle by experimentally infecting house crickets (Acheta domesticus) with O. petrowi eggs, feeding infected crickets to bobwhite and assessing the life-cycle of this nematode in both the definitive and intermediate hosts. METHODS: Oxyspirura petrowi eggs were collected from gravid worms recovered from wild bobwhite and fed to house crickets. The development of O. petrowi within crickets was monitored by dissection of crickets at specified intervals. When infective larvae were found inside crickets, parasite-free pen-raised bobwhite were fed four infected crickets each. The maturation of O. petrowi in bobwhite was monitored through fecal floats and bobwhite necropsies at specified intervals. RESULTS: In this study, we were able to infect both crickets (n = 45) and bobwhite (n = 25) with O. petrowi at a rate of 96%. We successfully replicated and monitored the complete O. petrowi life-cycle in vivo, recovering embryonated O. petrowi eggs from the feces of bobwhite 51 days after consumption of infected crickets. All life-cycle stages of O. petrowi were confirmed in both the house cricket and the bobwhite using morphological and molecular techniques. CONCLUSIONS: This study provides a better understanding of the infection mechanism and life-cycle of O. petrowi by tracking the developmental progress within both the intermediate and definitive host. To our knowledge, this study is the first to fully monitor the complete life-cycle of O. petrowi and may allow for better estimates into the potential for future epizootics of O. petrowi in bobwhite. Finally, this study provides a model for experimental infection that may be used in research examining the effects of O. petrowi infection in bobwhite.


Subject(s)
Colinus/parasitology , Gryllidae/parasitology , Life Cycle Stages , Thelazioidea/growth & development , Animals , Feces/parasitology , Texas , Time
20.
PLoS One ; 14(7): e0219303, 2019.
Article in English | MEDLINE | ID: mdl-31283777

ABSTRACT

From 1 January 2018 came into force Regulation (EU) 2015/2238 of the European Parliament and of the Council of 25 November 2015, introducing the concept of "novel foods", including insects and their parts. One of the most commonly used species of insects are: mealworms (Tenebrio molitor), house crickets (Acheta domesticus), cockroaches (Blattodea) and migratory locusts (Locusta migrans). In this context, the unfathomable issue is the role of edible insects in transmitting parasitic diseases that can cause significant losses in their breeding and may pose a threat to humans and animals. The aim of this study was to identify and evaluate the developmental forms of parasites colonizing edible insects in household farms and pet stores in Central Europe and to determine the potential risk of parasitic infections for humans and animals. The experimental material comprised samples of live insects (imagines) from 300 household farms and pet stores, including 75 mealworm farms, 75 house cricket farms, 75 Madagascar hissing cockroach farms and 75 migrating locust farms. Parasites were detected in 244 (81.33%) out of 300 (100%) examined insect farms. In 206 (68.67%) of the cases, the identified parasites were pathogenic for insects only; in 106 (35.33%) cases, parasites were potentially parasitic for animals; and in 91 (30.33%) cases, parasites were potentially pathogenic for humans. Edible insects are an underestimated reservoir of human and animal parasites. Our research indicates the important role of these insects in the epidemiology of parasites pathogenic to vertebrates. Conducted parasitological examination suggests that edible insects may be the most important parasite vector for domestic insectivorous animals. According to our studies the future research should focus on the need for constant monitoring of studied insect farms for pathogens, thus increasing food and feed safety.


Subject(s)
Edible Insects/parasitology , Insecta/parasitology , Parasitic Diseases/etiology , Animals , Cockroaches/parasitology , Europe , Food , Food Safety , Grasshoppers/parasitology , Gryllidae/parasitology , Humans , Parasitic Diseases, Animal/etiology , Tenebrio/parasitology
SELECTION OF CITATIONS
SEARCH DETAIL