Scuttle fly Megaselia scalaris (Loew) (Diptera: Phoridae) endoparasitoid as a novel biocontrol agent against adult American cockroaches (Periplaneta americana).

The American cockroach, Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae), is one of the most common pests that thrive in diverse environments and carries various pathogens, causing critical threats to public health and the ecosystem. We thus report in this study the first observation of decapitated American cockroaches as a result of infestation with scuttle fly parasitoids. Interestingly, behavioral alterations in the form of zombification-like behavior could be observed in cockroaches reared in the laboratory before being decapitated, implying that the insect targets cockroach heads. To identify this parasitoid, cockroaches' corpora were isolated in jars, and apodous larvae were observed. Larvae developed into small coarctate pupae, and adults emerged. The scuttle flies were collected and exhibited tiny black, brown, to yellowish bodies. The fly was initially identified based on its morphological properties as a member of the order Diptera, family Phoridae. To provide further insights into the morphological attributes of the phorid species, the fly was examined using a scanning electron microscope (SEM) and then identified as Megaselia scalaris accordingly. SEM analysis revealed the distinctive structure of M. scalaris concerning the head, mouth parts, and legs. Specifically, the mouth parts include the labrum, labellum, rostrum, and maxillary palps. Although further investigations are still required to understand the complicated relationships between M. scalaris and American cockroaches, our findings provide a prominent step in the control of American cockroaches using M. scalaris as an efficient biological control agent.

Gravid Periplaneta americana (Blattodea: Blattidae) Fails to Detect or Respond to the Presence of the Oothecal Parasitoid Aprostocetus hagenowii (Hymenoptera: Eulophidae).

Several families of parasitic Hymenoptera have evolved traits that allow them to exploit cockroach oothecae. Cockroaches may bury and conceal their oothecae to prevent parasitoid attack. However, these protective measures require additional investment by females. We hypothesized that gravid cockroaches would reduce parental care in the absence of oothecal parasitoids and increase care when parasitoids were detected. Behavior bioassays consisted of glass jars containing a gravid American cockroach, Periplaneta americana (L.) (Blattodea: Blattidae), expanded polystyrene (EPS), and a dog food pellet. A fruit fly (Drosophila melanogaster Meigen) (Diptera: Drosophilidae) or parasitoid Aprostocetus hagenowii (Ratzburg) (Hymenoptera: Eulophidae) was added for the fly and parasitoid treatments, respectively. There was no significant difference among treatments in the proportion of oothecae buried or in mean cover of oothecae with EPS particles. Cover had no effect on parasitism success or failure. Electroantennogram (EAG) assays using P. americana antennae were also conducted. The EAG responses to dead parasitoid stimuli (0.111-0.124 mV) were significantly (p < 0.05) greater than the negative control, but responses to living parasitoid stimuli (0.075-0.089 mV) were nonsignificant. These findings suggest that burial and concealment of oothecae is a general defensive behavior employed regardless of the presence or absence of a natural enemy. The results also indicate that gravid P. americana are unable to detect, and therefore, differentiate A. hagenowii from other insects and that A. hagenowii can successfully locate and parasitize oothecae completely concealed with EPS particles.

NEW DEFINITIVE HOST RECORD FOR CHORDODES MORGANI (NEMATOMORPHA) IN NEBRASKA WITH NOTES ON ECOLOGY.

The life cycle and ecology of the horsehair worm Chordodes morgani (Nematomorpha) in Nebraska remain unknown. To identify its definitive host, we installed a series of pitfall traps along 3 first-order streams at 4 sites: Elk Creek, Upper Elk Creek, Maple Creek, and West Oak Creek, all located northwest of Lincoln, Nebraska. In addition, we opportunistically hand-collected insects at these sites, including wood cockroaches (Parcoblatta virginica), and maintained them in the lab until they passed adult worms. Two of these field-collected wood cockroaches each yielded 1 adult worm, which was identified as C. morgani by microscopy, showing that P. virginica serves as a definitive host. Experimental infections of captive-reared Parcoblatta americana supported this result. The wood cockroach was found at all 3 creeks, but C. morgani was not found at West Oak Creek, suggesting that the definitive host does not limit the distribution of C. morgani. Physical properties of the streams were measured to examine how these properties influenced the distribution of the worm. Flow rate and pH differed between the 3 sites where C. morgani was found and the West Oak Creek site, suggesting an important role for these abiotic factors in the distribution of this horsehair worm species.

Complex and Diverse Drivers of Parasite Loads in a Cosmopolitan Insect.

The goal of parasite epidemiologists is to understand the factors that determine host infection levels. Potential infection determinants exist at many scales, including spatial and temporal environmental variation, among-host differences, and interactions between symbionts infecting the same host. All of these factors can impact levels of parasitism, but frequently only a subset is considered in any host-parasite system. We examined several potential determinants of pinworm infection in wild Australian cockroaches (Periplaneta australasiae) from multiple biological scales: (1) habitat; (2) season; (3) cockroach body size, developmental stage, and sex; and (4) interactions between 2 pinworm species (Leidynema appendiculata and Thelastoma sp.). Over 1 yr, we collected 239 cockroaches from 2 separate rooms in an Illinois greenhouse. We used generalized linear mixed-effects models (GLMMs) to evaluate simultaneously the influence of these factors on pinworm abundance, and nearly all had significant effects. Overall, the abundance of L. appendiculata was greater than Thelastoma sp., but the relative abundance of the 2 species was reversed in each room (i.e., a taxon × habitat effect). Abundance varied over 4 trapping seasons and increased with cockroach size. Adult cockroaches had more pinworms than nymphs, and there was also a significant taxon × stage effect: adult cockroaches had fewer pinworms than expected for their larger size, and this reduction was greater in Thelastoma sp. than in L. appendiculata. Cockroach sex had no effect on infection. Although females had more worms than males, this difference could be explained by the larger size of females. Finally, after controlling for all other potential determinants of infection, we found a strong negative association between Thelastoma sp. and L. appendiculata; cockroaches tended to be infected with either 1 pinworm species or the other. Our work underscores the importance of measuring potential determinants of infection from as many scales as possible. Such approaches are necessary to unravel the complexities of host-parasite interactions.

The role of the American cockroach (Periplaneta americana) as transport host of Eimeria tenella to chickens.

The role of the American cockroach, Periplaneta americana as transport host for Eimeria tenella was evaluated. Twenty-four cockroaches were orally fed with sporulated oocysts of E. tenella. Their feces and digestive tract were examined for oocysts by sugar centrifugal flotation technique and PCR. Infectivity of the oocysts recovered from the digestive tract of infected cockroaches as well as from their feces was evaluated by orally inoculating them into Boris Brown chickens. E. tenella oocysts were found in the digestive tract and feces of infected cockroaches up to day 4 after ingestion of oocysts. Furthermore, oocysts that were recovered from the digestive tract and feces of cockroaches remained infective for 4 and 3 days after ingestion of oocysts, respectively. Presence of oocysts in the feces of chicken that had been inoculated with either digestive tract or feces of P. americana demonstrated the infectivity of E. tenella oocysts from digestive tract or feces, suggesting that P. americana may play a role in the transmission of E. tenella among chicken and between chicken flocks.

Molecular cross-talk in a unique parasitoid manipulation strategy.

Envenomation of cockroach cerebral ganglia by the parasitoid Jewel wasp, Ampulex compressa, induces specific, long-lasting behavioural changes. We hypothesized that this prolonged action results from venom-induced changes in brain neurochemistry. Here, we address this issue by first identifying molecular targets of the venom, i.e., proteins to which venom components bind and interact with to mediate altered behaviour. Our results show that venom components bind to synaptic proteins and likely interfere with both pre- and postsynaptic processes. Since behavioural changes induced by the sting are long-lasting and reversible, we hypothesized further that long-term effects of the venom must be mediated by up or down regulation of cerebral ganglia proteins. We therefore characterize changes in cerebral ganglia protein abundance of stung cockroaches at different time points after the sting by quantitative mass spectrometry. Our findings indicate that numerous proteins are differentially expressed in cerebral ganglia of stung cockroaches, many of which are involved in signal transduction, such as the Rho GTPase pathway, which is implicated in synaptic plasticity. Altogether, our data suggest that the Jewel wasp commandeers cockroach behaviour through molecular cross-talk between venom components and molecular targets in the cockroach central nervous system, leading to broad-based alteration of synaptic efficacy and behavioural changes that promote successful development of wasp progeny.

Management of the American cockroach's oothecae: The potential of entomopathogenic fungi control.

The Periplaneta americana species is an annoyance to man, causing allergies and damage to clothes and documents. It has the ability to spread pathogens and requires control measures. Control with natural enemies is less aggressive and can currently be applied with less risk than other techniques, such as chemical control, which is the main method used worldwide to control its post-embryonic stages. The potential microbial control of nymphs and adults of this pest has been shown, but little is known about its oothecae. There are isolates of fungal species that can be used to achieve this aim, but they may have innate differences in their virulence and ability to spread. This study aimed to identify fungal isolates JAB 68 and IBCB 35 through genetic sequencing of the ITS1-5.8S-ITS2 region, analyze their ability to synthesize chitinase, and investigate and compare their aggressiveness against P. americana oothecae and their influence on nymph eclosion. Fungal suspensions were inoculated into minimal medium containing glucose (control) as the sole carbon source and 1% colloidal chitin to determine the chitinolytic activity on the 4th, 7th and 10th days and sporulation on the 10th day. To obtain mortality, extrusion and the compiled number of hatched nymphs, oothecae were sprayed with suspensions of the isolates as follows: T1 - no application; T2 - aqueous solution of Tween 80® 0.1% (vehicle suspension for treatments T3 to T8); T3 - 2 × 109 conidia/mL of the JAB 68 isolate; T4 - 2 × 108 con./mL of the JAB 68 isolate; T5 - 2 × 107 con./mL of the JAB 68 isolate; T6 - 2 × 109 con./mL of the IBCB 35 isolate; T7 - 2 × 108 con./mL of the IBCB 35 isolate; T8 - 2 × 107 con./mL of the IBCB 35 isolate. The JAB 68 and IBCB 35 isolates were identified as belonging to the species Metarhizium anisopliae and Beauveria bassiana, respectively. Chitinolytic activity and extrusion were good parameters for evaluating the fungi's action on oothecal control. The most aggressive entomopathogen was M. anisopliae isolate JAB 68, with shorter time for fungus extrusion at a concentration of 2 × 107 con./mL. B. bassiana reduced the number of hatched nymphs at a concentration of 2 × 108 con./mL. Both fungi are capable of infecting and killing P. americana's oothecae and reducing the number of nymphs hatched.

Experimental transmission of Toxocara canis from Blattella germanica and Periplaneta americana cockroaches to a paratenic host.

The present study assessed the capacity of Blattella germanica and Periplaneta americana to disseminate and transmit infective phases of T. canis to rats, which were used as a model paratenic host. P. americana and B. germanica inoculated orally with T. canis larvated eggs shed eggs and larvae in their fecal matter during the first 6days post-inoculation. Larvae were recovered from the brain, lungs, kidneys and liver of rats that had been inoculated with either infected cockroaches or their feces. ELISAs of serum detected an increase of antibodies anti-T. canis excretion-secretion antigens, whereas Western Blot (WB) showed 4 bands (120, 50, 35 and 28kDa) that were similar to those found in positive control rats. Macroscopically, the liver and kidneys of infected rats had hemorrhagic areas with milk-spot-like lesions. The lungs showed diffuse grey protuberances. Histologically, hemorrhagic areas with leucocytic infiltrate were observed in the liver, lungs and kidneys. Some larvae were found within a granuloma that was surrounded by eosinophils and other leucocytic infiltrates. Larvae were found in the brain, but without inflammatory infiltrate. Both cockroach species that ingested larvated eggs of T. canis may shed viable larvae or eggs in their fecal matter. The induction of specific serum antibodies, presence of larvae in tissues and characteristic lesions associated with larval migration in the organs of rats that had ingested either whole adults or feces of B. germanica or P. americana demonstrate the capacity of these cockroaches to transmit toxocariosis to paratenic hosts.

Cockroach Oothecal Parasitoid, Evania appendigaster (Hymenoptera: Evaniidae) Exhibits Oviposition Preference Towards Oothecal Age Most Vulnerable to Host Cannibalism.

Many female parasitoid wasps optimize host selection to balance the benefits of high-quality hosts and the costs of predator- or hyperparasitoid-induced mortality risks to maximize their fitness. Cannibalism exists in many insect species and affects survival of parasitoid larvae developing in or on parasitized hosts. However, little is known about how parasitoid wasps resolve the fitness consequence of host cannibalism-induced mortality risk during host selection. We examined the effect of oothecal age on cannibalism in the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae) and its effect on host age selection and fitness of its oothecal parasitoid Evania appendigaster (L.) (Hymenoptera: Evaniidae). P. americana differentially cannibalized 1-d-old (30‒60%) versus 10- to 40-d-old oothecae (<9%). However, parasitoid females did not avoid but still preferred to parasitize 1-d-old (45%) over 10- to 40-d-old oothecae (1.6‒20%). The parasitism rate was greater and the handling time was shorter on 1-d-old compared to older oothecae. For parasitoid progeny emerging from different-aged oothecae, regression analysis showed that development time increased and body size (measured as hind tibia length) and longevity decreased with oothecal age. These results demonstrate that reduced parasitoid progeny survival due to host cannibalism did not change the parasitoid's oviposition preference for newly laid oothecae, and that E. appendigaster females traded progeny survival for fitness gains for themselves and their progeny.

The cockroach Periplaneta americana as a potential paratenic host of the lungworm Aelurostrongylus abstrusus.

INTRODUCTION: Aelurostrongylus abstrusus is a well-known nematode affecting the respiratory system of felids worldwide. Snails and slugs act as intermediate hosts of this parasite, whereas rodents, birds and reptiles may serve as paratenic hosts. Periplaneta americana, the American brown cockroach, shares the same habitat and ecological features (e.g. nocturnal activity) with both snails and cats. The aim of this study was to evaluate the capability of P. americana to maintain alive A. abstrusus third stage larvae (L3s) after artificial inoculation. MATERIAL AND METHODS: Twenty-five specimens of P. americana were infected with 100 A. abstrusus L3s collected from experimentally infected Cornu aspersum snails, whereas five specimens were used as control group. After the infection, cockroaches were maintained in individual plastic boxes until dissection for the presence of L3s at 1 (T1), 5 (T5), 10 (T10), 15 (T15), and 20 (T20) days post-infection. RESULTS: Except for T15, alive A. abstrusus L3s (n = 63) were found at all time-points, being 26, 19, 16 and 2 L3s retrieved at T1, T5, T10 and T20, respectively. Eleven (17.4%) L3s were found within the digestive tract, 10 (15.9%) in other-than-digestive organs and 42 (66.7%) in the exoskeleton and associated tissues. Nine out of the twenty-five experimentally inoculated cockroaches (36%) died soon after the artificial infection (T1), while in the control group, two out of the five (40%) died before the end of the study (T15) with no difference in the mortality rate between groups. DISCUSSION: Results of this study suggest that P. americana could act as a paratenic host of A. abstrusus. Periplaneta americana cockroaches, have a ubiquitous distribution and may be preyed by cats, representing a potential source of infection to cats living in endemic areas.

Influences of Temperature and Ootheca Age on the Life History of the Cockroach Ootheca Parasitoid Aprostocetus hagenowii (Hymenoptera: Eulophidae).

The influences of ootheca age and temperature on the life history of Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious ootheca parasitoid of the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae), were evaluated. Oothecae were incubated at 20, 25, and 30 °C to produce oothecae aged 1-60, 1-40, and 1-30 d old, respectively. Fitness traits (development time, percentage emergence, number of progeny, percentage female progeny, and female body size) of A. hagenowii developing in these different-aged oothecae were determined. For oothecae incubated at 20, 25, and 30 °C, parasitoids successfully developed in oothecae aged up to 50, 30, and 20 d old, which represent 72.9%, 65.9%, and 61.9% of the total embryonic development time of P. americana, respectively, without any changes in their fitness traits. When A. hagenowii from oothecae kept at constant temperatures (20, 25, 30, 32, and 35 °C) were compared, the immature development time (71.0-34.0 d) and adult life span decreased with increasing temperature. No parasitoid emerged at 35 °C. The lower, upper, and optimal temperature-dependent developmental thresholds were 9.5, 34.2, and 31.1 °C, respectively. Thermal constant for total immature development was 666.7 degree-days. Temperature did not affect lifetime realized fecundity and number of oothecae parasitized by females but did influence parasitism activities over time. Sugar-fed females sustained longer periods of high parasitism rates (≥70%) at 20-30 °C (15-30 d) than at 32-35 °C (1-5 d). These results are useful for determining the ootheca age and temperature range optimal for parasitoid rearing and for estimating the effectiveness of biological control by the wasps.

First record of Hammerschmidtiella diesingi (Hammerschmidt, 1838) (Oxyuridomorpha: Thelastomatidae) parasite of Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae) in Japan, morphological and molecular characterization.

Nematodes, belonging to the family Thelastomatidae, are parasites of saprophytic terrestrial arthropods, mainly cockroaches. American cockroach Periplaneta americana (Linnaeus, 1758) has high environmental adaptability, and has been spread worldwide by human activity. There are several reports of thelastomatid parasitic nematodes of P americana in the world. Here, the thelastomatid nematode Hammerschmidtiella diesingi (Hammerschmidt, 1838) (Oxyuridomorpha: Thelastomatidae), isolated from P americana is recorded for the first time in Japan. Through morphometrics, DIC and SEM observations, we confirmed that specimens of the present study agree with previous records of H. diesingi. DNA sequencing of the partial D2/D3 LSU expansion segment of the 28S ribosomal RNA gene revealed that H. diesingi from Japan matches with H. diesingi from other countries. Our contributions are very useful and fundamental for further analysis of the cockroach and parasite relations.

Morphological, molecular and developmental characterization of the thelastomatid nematode Thelastoma bulhoesi (de Magalhães, 1900) (Oxyuridomorpha: Thelastomatidae) parasite of Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae) in Japan.

The American cockroach Periplaneta americana (Linnaeus, 1758) (Blattodea: Blattidae) has been spreading worldwide by commerce and has successfully adjusted to living with humans. There are many reports of thelastomatid parasitic nematode isolated from P. americana in many countries including USA, Canada, India, Argentina, Bulgaria, but not in Japan. We have investigated the parasitic nematodes in P. americana lab strain and field-captured individuals in Japan and found that Thelastoma bulhoesi (de Magalhães, 1900) (Oxyuridomorpha: Thelastomatidae) parasitizes with high infection rates. We described morphological, molecular, and developmental characters of the parasitic nematode because such information was missing despite it has been discovered more than one hundred years ago. We described morphometrics with DIC microscopy and fine structure of male and female adult with SEM observation. We also reveal the embryonic and postembryonic development of this nematode. This is the first report of a thelastomatid nematode isolated from American cockroach in Japan, and the data showed here is also very useful and fundamental for further analysis of the cockroach and parasite relations.

Water balance profiles, humidity preference and survival of two sympatric cockroach egg parasitoids Evania appendigaster and Aprostocetus hagenowii (Hymenoptera: Evaniidae; Eulophidae).

The impact of desiccation on habitat selection, foraging and survival has been characterized for many insects. However, limited information is available for parasitic wasps. In this study, water balance, relative humidity (RH) preference, and effect of humidity on survival of solitary Evania appendigaster (L.) (Hymenoptera: Evaniidae) and gregarious Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae) were examined. These species are both oothecal parasitoids of the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae). E. appendigaster had significantly higher cuticular permeability (CP) and a lower surface area to volume ratio but a similar percentage of total body water content compared to A. hagenowii. No differences in these attributes were found between sexes of each parasitoid species. The percentage of total body water loss rates among E. appendigaster males and females and A. hagenowii females were similar but significantly lower than that of A. hagenowii males. All parasitoids except E. appendigaster males exhibited reduced survival times as the RH of their enclosure decreased from 87% to 38%, but this phenomenon did not occur when parasitoids were given a sugar solution. In environmental chambers with a 44-87% RH gradient, both sexes of E. appendigaster resided significantly more often in the 87% RH chamber than in the 44% RH chamber. For A. hagenowii, females preferred both the driest and the wettest chambers and males preferred the driest ones. These results demonstrate the water balance profile and its relationship to life history traits and differential responses to RH in these competing parasitoid wasps, suggesting the role of physiological and behavioral adaptations in shaping their ecological niche.

Tomaculocystis corpulenta n. gen., n. sp. (Apicomplexa: Eugregarinorida) parasitizing the little yellow cockroach, Cariblatta lutea (Blattodea: Ectobiidae), in Alabama and Florida with recognition of Tomaculocystis cylindrosa n. comb. and Tomaculocystis mukundai n. comb. parasitizing ectobiid cockroaches in India.

Tomaculocystis corpulenta n. gen., n. sp. (Apicomplexa: Eugregarinorida: Septatorina: Gregarinidae) is described from populations of the little yellow cockroach, Cariblatta lutea (Blattodea: Ectobiidae), established in laboratory culture from samples collected in Alabama and Florida. Tomaculocystis n. gen. are differentiated from other members of Gregarina by a markedly elliptoid gametocyst inside a persistent, lomentiform hyaline epicyst; developmental organization and growth of the spore tubes from gametocyst surface tumidi; and dehiscence by extrusion of non-chain forming oocysts through spore tubes that barely extend beyond the epicyst wall. Gregarina cylindrosa, Gregarina discocephala, and Gregarina mukundai are recognized as members of Tomaculocystis, and G. cylindrosa is recognized as the senior synonym of G. discocephala. Thus, Tomaculocystis cylindrosa n. comb. and Tomaculocystis mukundai n. comb. are formed. Species of Tomaculocystis are distinguished based on gamont deutomerite and oocyst shape and size. The oocysts of T. corpulenta are broadly dolioform, lack 4 polar knobs, and possess distinct, unique polar plates. Oocysts of all other known species in the genus are more oblong in shape, possess 4 polar knobs, and lack the distinct polar plates observed in the oocysts of T. corpulenta. Host utilization and geographic distribution among gregarine genera parasitizing the cockroach family Ectobiidae reveal a pattern of host-parasite specificity linking gregarine genera with ectobiidid subfamilies. Overall patterns suggest a hypothesis of European endemicy for Gamocystis, but hypotheses for the origin and radiation of Tomaculocystis or species of Gregarina infecting cockroaches are confounded by the cosmopolitan spread of pest cockroach species among humans.

First report of the nematode Leidynema appendiculata from Periplaneta fuliginosa.

The smokybrown cockroach Periplaneta fuliginosa has spread all over the world, and is now one of the most undesired invasive alien pests in Japan. Because cockroaches are generally infected by thelastomatid nematodes, they are being distributed around the world with their parasitic nematodes. Nothing is known about parasitic nematode species in P. fuliginosa differences, or similarity of the parasite's population structures between the different countries of the host cockroaches. Here we investigated the P. fuliginosa invasive to Japan and found that 100% of individuals were infected with one nematode species. According to the morphology and the sequence of the D2/D3 expansion segment of the 28S ribosomal RNA gene, we identified the parasite as Leidynema appendiculata. This nematode reproduced by haplodiploidy and its developmental timing under various conditions is quite divergent. Their population in the hindgut of P. fuliginosa was controlled with a few adult females and a male. This is the first report of the thelastomatid nematode isolated from the smokybrown cockroach, and is the basis for our future research examining the origin, distribution route and immigration history of the cockroach and the impact of L. appendiculata on native Japanese cockroach species.

Molecular characterization of two insect nematode species (Oxyurida: Thelastomatidae) using small subunit (18S) ribosomal DNA sequence and secondary-structure analyses.

Nematodes of the family Thelastomatidae are parasitic in the alimentary tract of many arthropods, including Periplaneta americana L. In Meerut, Uttar Pradesh, India, two nematode species, namely Hammerschmidtiella indicus and Thelastoma icemi, belonging to this family have been reported. In the present study, the molecular phylogeny of these two nematode species was derived using small subunit (18S) sequence and secondary-structure analyses. The small subunit sequence analyses were carried out to explore the validation and systematics of these species. Phylogenetic analyses were performed for primary sequence data as well as using neighbour-joining and maximum-parsimony approaches. In contrast, the inferred secondary structures for the two species, using free-energy modelling, showed structural identities. As well as this, motif sequences were also found to be a promising tool for nematode species identification. The study provides molecular characterization based on primary sequence data of the 18S ribosomal DNA region of the nematodes along with secondary-structure data and motif sequences for inferences at higher taxonomic levels.

Larvae of the parasitoid wasp Ampulex compressa sanitize their host, the American cockroach, with a blend of antimicrobials.

Food resources contaminated with spoilage or pathogenic microorganisms pose severe problems to all higher organisms. Here, we describe a food-hygienic strategy of the emerald cockroach wasp Ampulex compressa. The wasp larvae develop on and inside the American cockroach Periplaneta americana, a host that can harbor various putrefactive microbes, as well as human and insect pathogens. From P. americana, we isolated the Gram-negative bacterium Serratia marcescens, which is a potent entomopathogen that can rapidly kill insect larvae. It is also known as a food contaminant and as an opportunistic human pathogen. Using behavioral observations and chemical analyses, we demonstrated that A. compressa larvae impregnate their cockroach hosts from inside with large amounts of an oral secretion containing a blend of γ-lactones and isocoumarins with (R)-(-)-mellein [(R)-(-)-3,4-diydro-8-hydroxy-3-methylisocoumarin] and micromolide [(4R,9Z)-octadec-9-en-4-olide] as dominant components. We fractionated hexane extracts of the secretion and investigated the antimicrobial properties of the fraction containing the lactones and isocoumarins, as well as of synthetic (R)-(-)-mellein and micromolide, against S. marcescens and a Gram-positive bacterium, Staphylococcus hyicus, in broth microdilution assays. The test fraction inhibited growth of both tested bacteria. The activity of the fraction against S. marcescens was explained by (R)-(-)-mellein alone, and the activity against S. hyicus was explained by the combined action of (R)-(-)-mellein and micromolide. Our data suggest that the specific combination of antimicrobials in the larval secretion provides an effective frontline defense against the unpredictable spectrum of microbes that A. compressa larvae may encounter during their development inside their cockroach hosts.