Solitary Parasitoid Research Articles

Hymenopteran Parasitoids of Leucotaraxis argenticollis (Diptera: Chamaemyiidae) and Leucotaraxis piniperda: Implications for Biological Control of Hemlock Woolly Adelgid (Hemiptera: Adelgidae).

The hemlock woolly adelgid (Adelges tsugae (Annand)) is a serious invasive pest of hemlock trees in eastern North America. Multiple biological control agents have been the focus of research aimed at pest management and conserving hemlock communities. Three promising A. tsugae specialist predators are the beetle Laricobius nigrinus (Fender) (Coleoptera: Derodontidae) and flies in the genus Leucotaraxis (Diptera: Chamaemyiidae), Leucotaraxis argenticollis (Zetterstedt), and Leucotaraxis piniperda (Malloch). However, these flies are vulnerable to parasitism by wasps in the genera Pachyneuron (Walker) (Hymenoptera: Pteromalidae) and Melanips (Walker) (Hymenoptera: Figitidae). This study explores parasitoid wasp interactions with these Leucotaraxis species in their native western North American range and potential impacts on the biological control program in the East. Leucotaraxis, La. nigrinus, and parasitoid emergences were observed from adelgid-infested foliage collected from Washington State and British Columbia in 2018, 2019, and 2020. Undescribed species of Pachyneuron and Melanips emerged from puparia as solitary parasitoids. Parasitoid emergence was positively correlated with Leucotaraxis emergence. Percent parasitism increased between February and July, with the months of June and July experiencing higher parasitoid emergence than Leucotaraxis. Differences in emergence patterns suggest that Pachyneuron may be more closely associated with Le. argenticollis as a host, and that Melanips may be associated with Le. piniperda. High parasitism in Leucotaraxis had no effect on La. nigrinus larval abundance, whereas the combined emergence of parasitoids and Leucotaraxis was positively correlated with La. nigrinus. This suggests that there is limited competition among these predators.

Parasites of Leucinodes orbonalis Guenee from Manipur

Leucinodes orbonalis Guenée (Lepidoptera: Crambidae) is a serious pest of brinjal. During the field observations, a solitary larval parasitoid of L. orbonalis viz., Trathala flavoorbitalis (Cameron) (Hymenoptera: Ichneumonidae) was osberved. The present study reports larval parasitism of L. orbonalis with 6% field parasitism by T. flavoorbitalis in Manipur.

Sympiesis notata (Hymenoptera: Chalcidoidea: Eulophidae), a gregarious parasitoid of Hesperiidae (Lepidoptera), and some records of other Chalcidoidea associated with skipper butterflies in the Western Palaearctic

Sympiesis notata is a gregarious ectoparasitoid of skipper butterfly caterpillars. Other Lepidoptera larvae in leaf mines and leaf folds are attacked by the same morphospecies, but on these smaller hosts S. notata is usually a solitary parasitoid. Other Chalcidoidea recorded as reared from hesperiid hosts are mostly species of Brachymeria (Chalcididae) and Elasmus (Eulophidae), which are primary parasitoids, and Catolaccus (Pteromalidae) which are pseudohyperparasitoids attacking cocooned ichneumonoid primary parasitoids. Species of Pteromalus, Baryscapus and Tetrastichus are also reported as secondary parasitoids from hesperiid hosts.

Echoentomography for Assessing Braconid Parasitization on Soft-Bodied Tephritid Hosts.

Simple SummaryHost parasitization by an endoparasitoid insect can be evaluated relying on three main methods, i.e., dissection under a stereomicroscope, polymerase chain reaction (PCR), or waiting for adult emergence. These approaches show limitations related to the time required for the detection of parasitization and/or the destruction of the sample. In this research, an innovative approach using ultra-high frequency ultrasound (UHFUS) technology was employed to evaluate braconid parasitization of Ceratitis capitata larvae. The UHFUS approach was compared with classic stereomicroscopic dissection, showing that both methods provide comparable diagnostic reliability. Our results support the application of echoentomography as a useful tool for fine, fast, and non-invasive evaluation of the ability of parasitoids to parasitize soft-bodied hosts.Entomological approaches currently available for assessing host parasitization require dissection, polymerase chain reaction (PCR), or waiting for adult emergence. The first two methods are relatively fast but destructive, whereas the third one allows the emergence of the parasitoid but it is time consuming. In this framework, new diagnostic imaging tools may contribute to solve the lack of an accurate, rapid, and non-invasive approach to evaluate the parasitization of soft-bodied insects by their endoparasitoids. In this study, ultra-high frequency ultrasound (UHFUS) technology, which is currently used in medical and preclinical fields, was adopted to assess the parasitization of the invasive polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), testing 2nd and 3rd instar larvae. Parasitization assays were carried out with the solitary koinobiont endophagous parasitoid Psyttalia concolor (Hymenoptera: Braconidae: Opiinae). The efficacy of UHFUS-based echoentomography was compared with the classical method of dissecting the larval host under a stereomicroscope. Our results showed that the UHFUS diagnostic capability was statistically comparable with that of dissection, both on C. capitata 2nd and 3rd larvae. Overall, UHFUS-based echoentomography may be further considered as a fast, non-invasive, and effective approach to evaluate the parasitoid’s ability to successfully oviposit in soft-bodied hosts.

Microhabitats Utilization by Solitary Parasitoids and Predatory Insects as Indicators of Oil Palm Agroecosystem’s Capacity to Support Insect Species Diversity

Microhabitats capacity to support insect species diversity and persistence were evaluated implementing solitary parasitoids and predatory insects according to different phases of herbicide and chemical fertilizer applications. Two species of the genus Xanthopimpla (Ichneumonidae) and one species of the genus Pompilus (Pompilidae) showed relationships on vegetation-type microhabitats, notably natural weeds, leguminous cover crops, and the beneficial plant Turnera subulata, while two species of the genus Evania (Evaniidae) showed relationships with chipped oil palm trunks. One species from the genus Odontomachus (Formicidae) as an exclusive predatory ant was related to both chipped oil palm trunks and the beneficial plant T. subulata. Xanthopimpla parasitoids exhibited abundance fluctuations difference around natural weeds during herbicide application phases between three- and six-years old oil palm stands, with decreased and increased abundance patterns of the former and the latter, respectively. 18 years old oil palm stand showed increased abundance patterns only along with the different phases of chemical fertilizer applications. The importance of natural weeds diversity, restrictions of leguminous cover crops, frequency of herbicide applications, and the arrangements between beneficial plants and wood-based microhabitats that benefited insect parasitoids and predators were discussed.

FIRST RECORD OF Brachymeria podagrica (HYMENOPTERA: CHALCIDIDAE) AS PARASITOID OF Peckia collusor (DIPTERA: SARCOPHAGIDAE)

In this work, the wasp Brachymeria podagrica is recorded for the first time for Colombia, a solitary parasitoid of larvae of the Peckia collusor fly. Third instar larvae of P. collusor were exposed to outdoor ambient conditions for 6 hours in the garden of the Tecnológico de Antioquia (Medellín, Colombia). 29 B. podagrica adults were obtained from the host pupae. Prevalence of parasitism was 14.5 %.

Parasitoid Species Associated with Immature Stages <i>pieris rapae</i> (L.) Inhabiting Cabbage Plantations in Assiut Governorate, Upper Egypt

This work was initiated for the first time to identify parasitoid species associated with the immature stages of <i>Pieris rapae</i> (L.) inhabiting cabbage plantations in Assiut governorate, Upper Egypt during the 2018 and 2019 cabbage growing seasons. Attacking periods and parasitism percentages (PPs) of the identified parasitoid species were calculated. One solitary parasitoid species, <i>Hyposoter ebeninus</i> was found to attack <i>P. rapae</i> larvae in the field 110 days after transplantation. However, one hyperparasitoid species <i>Baryscapus galactopus</i> was recorded as an internal gregarious hyperparasitoid of <i>H. ebeninus</i>. The solitary larval parasitoid <i>H. ebeninus</i> strikes were recorded throughout the last five weeks of the season with a marked decline before harvesting. Although <i>H. ebeninus</i> revealed 42.00% abundance, it presented 21.69% PP on <i>P. rapae</i> larvae during the entire period of study. One solitary, <i>Brachymeria femorata</i> and two gregarious parasitoid species [<i>Pteromalus puparum</i> (L) and <i>Tetrastichus</i> sp. (Haliday) were recorded as <i>P. rapae</i> pupae parasitoids on October, 2^nd. Parasitism peak was recorded on October, 16^th with an average of 56.25%. The first appearance of the gregarious pupal parasitoid <i>P. puparum</i> was recorded on October, 9^th. Four weeks later, the second gregarious parasitoid (<i>Tetrastichus</i> sp.) was recorded on November, 6^th. Both pupal gregarious parasitoid species were found to be active until harvesting. The gregarious parasitoid <i>P. puparum</i> presented high PP (23.73%) as compared with <i>Tetrastichus</i> sp. which exhibited 6.96% PP during the entire period of study. In conclusion, two solitaries, one hyperparasitoid, and two gregarious parasitoid species were identified. Pupal gregarious parasitoid species together reduced <i>P. rapae</i> pupae populations by 30.69%. These parasitoids could be used in the IPM programs for this pest in the future. At the same time, the effect of hyperparsitoides must be taken into consideration.

Asymmetries affecting aggressive contests between solitary parasitoids: the effect of host species

Abstract Conflicts in animals are usually resolved based on asymmetries, where contest winners are often those that value a resource the most and/or those who have the greatest potential to retain it. In parasitoid wasps, contests between females determine which individual exploits hosts for offspring production. Previous studies on solitary parasitoids rarely considered the role of biotic factors generating phenotypic variation that could influence the strength of asymmetries. Some parasitoid species parasitize host species of various sizes, producing offspring that vary considerably in size and potentially fighting ability. In this study, we reared the egg endoparasitoid Telenomus podisi (Hymenoptera: Scelionidae) on two host species to measure the effect of body size on contest resolution and how it interacts with ownership and resource value (RV) asymmetries. Our results showed that ownership status best predicts the final contest outcome when similar-sized wasps fight over hosts. The frequency and outcomes of individual fights structuring contests were better explained by the difference in the number of eggs laid in the hosts by each female at a given time. When contestants varied in body size, larger intruders frequently dislodged small owners regardless of ownership and RV asymmetries. These results imply that body size is an important factor to consider in solitary parasitoid contests and that it can overshadow the effects of other asymmetries. Our study suggests that host community diversity could have a direct effect on parasitoid contests and that biotic communities, through their effects on animal phenotypes, may play an underrated role in contest resolution.

Mechanism and consequences for avoidance of superparasitism in the solitary parasitoid Cotesia vestalis

A parasitoid’s decision to reject or accept a potential host is fundamental to its fitness. Superparasitism, in which more than one egg of a given parasitoid species can deposit in a single host, is usually considered sub-optimal in systems where the host is able to support the development of only a single parasitoid. It follows that selection pressure may drive the capacity for parasitoids to recognize parasitized hosts, especially if there is a fitness cost of superparasitism. Here, we used microsatellite studies of two distinct populations of Cotesia vestalis to demonstrate that an egg laid into a diamondback moth (Plutella xylostella) larva that was parasitized by a conspecific parasitoid 10 min, 2 or 6 h previously was as likely to develop and emerge successfully as was the first-laid egg. Consistent with this, a naive parasitoid encountering its first host was equally likely to accept a healthy larva as one parasitized 10 min prior, though handling time of parasitized hosts was extended. For second and third host encounters, parasitized hosts were less readily accepted than healthy larvae. If 12 h elapsed between parasitism events, the second-laid egg was much less likely to develop. Discrimination between parasitized and healthy hosts was evident when females were allowed physical contact with hosts, and healthy hosts were rendered less acceptable by manual injection of parasitoid venom into their hemolymph. Collectively, these results show a limited capacity to discriminate parasitized from healthy larvae despite a viability cost associated with failing to avoid superparasitism.

Revisiting the host use and phylogeny of Colastomion Baker (Hymenoptera, Braconidae, Rogadinae), with a new host record from Japan

We report the solitary parasitism by Colastomion formosanum (Watanabe) (Hymenoptera, Braconidae, Rogadinae) on the larva of Nevrina procopia (Stoll) (Lepidoptera, Crambidae) feeding on Turpinia ternata Nakai (Staphyleaceae) in Amami Ôshima Is., Japan. This is the first host record for the genus Colastomion Baker outside of Papua New Guinea. We have also inferred the phylogenetic relationships of Colastomion species using Bayesian and maximum likelihood approaches, based on the mitochondrial cytochrome oxidase 1 gene. The results indicate two major clades–solitary and gregarious parasitoids–within Colastomion. Colastomion formosanum belongs to the clade of solitary parasitoids that specifically parasitize the crambid subfamily Spilomelinae. Plant-host-parasitoid associations and the evolutionary scenario of the host use of Colastomion are discussed.

Host plants alter their volatiles to help a solitary egg parasitoid distinguish habitats with parasitized hosts from those without

Host plants alter their volatiles to help a solitary egg parasitoid distinguish habitats with parasitized hosts from those without

Who wins? Ray spiders (Theridiosoma gemmosum) (Araneae: Theridiosomatidae) versus egg sac parasitoids

This is the first report on the parasitoids of egg sacs of Theridiosoma gemmosum (L. Koch, 1877) (Theridiosomatidae). The parasitic wasps Gelis melanocephalus (Schrank, 1781), Gelis mangeri (Gravenhorst, 1815) (Ichneumonidae) and Pachyneuron solitarium (Hartig, 1838) (Pteromalidae) were recorded as solitary parasitoids of egg sacs of T. gemmosum in Poland. The degree of parasitism of T. gemmosum egg sacs in three different years was 21.4–42.9%, and the reproductive fitness of female spiders in all cases of parasitized cocoons was zero. It seems that the suspension system of the egg sacs of ray spiders is not a barrier against egg sac parasitoids, including apterous species. We hypothesize that, at least in the case of G. melanocephalus, the size of the spider's egg sac is implicated in the ovipositional decision of the female parasitoid.

Effects of parental diapause status and release time on field reproductive biology of the introduced egg parasitoid, Oobius agrili (Hymenoptera: Encyrtidae) in the Mid-Atlantic: Implications for biocontrol of the emerald ash borer (Coleoptera: Buprestidae)

Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae), a solitary egg parasitoid native to China, was introduced to the United States for biocontrol of the invasive emerald ash borer (EAB) Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in 2007. To help develop effective biocontrol-release strategies, we evaluated the effect of parental diapause and release time of the adult parasitoids on their longevity, realized fecundity, and progeny diapause rate under field conditions in the U.S. Mid-Atlantic region in 2016 and 2017. Results from two years of the study showed that both non-diapaused and diapaused O. agrili adults released in rearing containers exposed to field conditions in late spring to early summer (from May 26 to July 20th) successfully survived and reproduced on emerald ash borer eggs provided throughout the study period. The parental parasitoid diapause status and release time did not significantly affect the longevity and life-time fecundity of the released adult parasitoids except that both diapaused and non-diapaused parasitoids released on May 26th of 2017 produced significantly fewer progeny than those from later releases (June 14th and July 20th) of the same year. In both 2016 and 2017, non-diapaused parasitoids consistently produced a higher proportion of diapaused progeny than diapaused parasitoids, regardless of release times. These findings indicate that releases of O. agrili with different diapause status from late spring to early summer may cause variations in establishing overwintering parasitoid populations for biological control of emerald ash borer in the field.

Pre‐release packing and chilling reduce host‐searching ability of the parasitoid Diachasmimorpha longicaudata used in the augmentative control of tephritid flies

AbstractDiachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is a solitary parasitoid used in augmentative releases to control Tephritidae (Diptera) fruit flies of economic importance. Pre‐release process includes packing adult parasitoids in cages at high densities and expose them to a temperature of 2 ± 2 °C during 105 min. In this process, females’ antennae may be damaged resulting in a reduction in their host‐searching ability and fecundity. Here we measured, for five consecutive days after chilling, the searching ability and fecundity of parasitoids with damaged (D) and undamaged (ND) antennae compared with parasitoids that were not chilled. Female individual responses to fruit infested by Anastrepha spp. was determined in an olfactometer. Latency in the response and latency in making a choice were recorded. Additionally, groups of 30 females were used to measure their ability to find hosts in infested fruit in the laboratory. Fecundity was determined by using artificial oviposition units with Anastrepha ludens (Loew) larvae. In the olfactometer test, ND had lower response than control females during the 1st and 2nd days after chilling. However, no difference in the response was observed between ND and D and the control females on the 5th day. Additionally, chilled females showed a longer latency of response to infested fruit than females of the control treatment when tested in groups. However, after a 24–48 h period, no difference between D and ND and control females was observed. Our results showed similar searching ability and fecundity among parasitoids of the three tested conditions at individual and at group levels. We conclude that pre‐release chilling reduces female searching ability only for the first 1–2 days after chilling.

Redescriptions of two parasitoids, Metapelma beijingense Yang (Hymenoptera, Eupelmidae) and Spathius ochus Nixon (Hymenoptera, Braconidae), parasitizing Coraebus cavifrons Descarpentries & Villiers (Coleoptera, Buprestidae) in China with keys to genera or species groups.

Two parasitoids, Metapelma beijingense Yang (Hymenoptera, Eupelmidae) and Spathius ochus Nixon (Hymenoptera, Braconidae) are redescribed and illustrated. Both were reared from Coraebus cavifrons Descarpentries & Villiers (Coleoptera, Buprestidae) boring in Symplocos stellaris Brand (Symplocaceae). Metapelma beijingense is a solitary parasitoid with a parasitism rate of about 13.5% and S. ochus is a gregarious parasitoid with a parasitism rate of about 21.2%. A revised key to Oriental and Palaearctic species of Metapelma Westwood and a key to the species of the Spathius labdacus-group are provided.

Does the solitary parasitoid Microplitis pennatulae use a combinatorial approach to manipulate its host?

AbstractHost manipulation is a strategy used by some parasites to enhance their transmission. These parasites use a combination of neuropharmacological, psychoneuroimmunological, genomic/proteomic, or symbiont‐mediated mechanisms to manipulate their hosts. Bodyguard manipulation occurs when parasitized hosts guard parasitoid pupae to protect them from their natural enemies. Bodyguard‐manipulated hosts exhibit altered behaviours only after the egression of parasitoid prepupae. Behavioural changes in post‐parasitoid egressed hosts could have resulted from their altered physiology. Previous studies have shown that gregarious manipulative parasitoids induce multiple physiological changes in their host, but the physiological changes induced by solitary manipulative parasitoids are unknown. Microplitis pennatulae Ranjith &amp; Rajesh (Hymenoptera: Braconidae) is a larval parasitoid of Psalis pennatula Fabricius (Lepidoptera: Erebidae). After the egression of parasitoid prepupae, P. pennatula stops its routine activities and protects the parasitoid pupa from hyperparasitoids by body thrashes. In this study, we looked into the physiological changes induced by the solitary manipulative parasitoid, M. pennatulae, in its host, P. pennatula, during various stages of parasitization. We considered octopamine concentration and phenoloxidase (PO) activity as biomarkers of physiological change. We also examined whether M. pennatulae has a symbiotic virus and whether the wasp transfers it to the host during parasitization. We found that octopamine concentration was low in the pre‐parasitoid egressed host, but it was elevated after the parasitoid egressed. Phenoloxidase activity was lower in the pre‐ and post‐parasitoid egressed host than in the unparasitized host. We also detected symbiotic bracovirus (BV) in the wasp ovaries and isolated the BV virulence gene from the parasitised host. Our study suggests that solitary parasitoids also induce multiple physiological changes to influence the host behaviour to their advantage, as is the case with the gregarious parasitoids.

Host plants alter their volatiles to help a solitary egg parasitoid distinguish habitats with parasitized hosts from those without.

When attacked by herbivores, plants emit volatiles to attract parasitoids and predators of herbivores. However, our understanding of the effect of plant volatiles on the subsequent behaviour of conspecific parasitoids when herbivores on plants are parasitized is limited. In this study, rice plants were infested with gravid females of the brown planthopper (BPH) Nilaparvata lugens for 24 hr followed by another 24 hr in which the BPH eggs on plants were permitted to be parasitized by their egg parasitoid, Anagrus nilaparvatae; volatiles from rice plants that underwent such treatment were less attractive to subsequent conspecific parasitoids compared to the volatiles from plants infested with gravid BPH females alone. Chemical analysis revealed that levels of JA and JA-Ile as well as of four volatile compounds-linalool, MeSA, α-zingiberene and an unknown compound-from plants infested with BPH and parasitized by wasps were significantly higher than levels of these compounds from BPH-infested plants. Laboratory and field bioassays revealed that one of the four increased chemicals-α-zingiberene-reduced the plant's attractiveness to the parasitoid. These results suggest that host plants can fine-tune their volatiles to help egg parasitoids distinguish host habitats with parasitized hosts from those without.

Discovery of the genus Venanides Mason 1981 (Hymenoptera: Braconidae, Microgastrinae) in Europe, with description of a new species parasitizing Carcina quercana (Fabricius) (Lepidoptera: Peleopodidae)

The small Microgastrinae genus Venanides is recorded from Europe (Netherlands, Germany and Czech Republic) for the first time, where one species, Venanides carcinae sp. nov., described here, proves to be a regular solitary parasitoid of Carcina quercana. Outline notes on its biology, phenology and abundance are given.

Distinct Roles of Cuticular Aldehydes as Pheromonal Cues in Two Cotesia Parasitoids.

Cuticular compounds (CCs) that cover the surface of insects primarily serve as protection against entomopathogens, harmful substances, and desiccation. However, CCs may also have secondary signaling functions. By studying the role of CCs in intraspecific interactions, we may advance our understanding of the evolution of pheromonal communication in insects. We previously found that the gregarious parasitoid, Cotesia glomerata (L.), uses heptanal as a repellent pheromone to help avoid mate competition among sibling males, whereas another cuticular aldehyde, nonanal, is part of the female-produced attractive sex pheromone. Here, we show that the same aldehydes have different pheromonal functions in a related solitary parasitoid, Cotesia marginiventris (Cresson). Heptanal enhances the attractiveness of the female's sex pheromone, whereas nonanal does not affect a female's attractiveness. Hence, these common aldehydes are differentially used by the two Cotesia species to mediate, synergistically, the attractiveness of the main constituents of their respective sex pheromones. The specificity of the complete sex pheromone blend is apparently regulated by two specific, less volatile compounds, which evoke strong electroantennographic (EAG) responses. This is the first demonstration that volatile CCs have evolved distinct pheromonal functions to aid divergent mating strategies in closely related species. We discuss the possibility that additional compounds are involved in attraction and that, like the aldehydes, they are likely oxidative products of unsaturated cuticular hydrocarbons.

Faunistic analysis of Ichneumonidae (Hymenoptera) in Guarana (Paullinia cupana) crop, with new records of genera for the Brazilian Amazon

ABSTRACT: Ichneumonidae are solitary parasitoids that mainly attack larvae and pupae of Lepidoptera, Coleoptera and Hymenoptera, which constitute important agricultural pests. The objective of the present paper was to characterize the assemblage of Ichneumonidae associated to the conventional and organic cultivation of Guarana (Paullinia cupana) crop in Manaus City (Amazonas State, Brazil) with faunistic analysis. The samples were collected at Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), using Malaise and Moericke traps, between September 2012 and February 2013. We collected 296 specimens of Ichneumonidae, represented by 14 subfamilies, 41 genera and 63 morphospecies. The faunistic analysis revealed the predominance of rare and less frequent genera (54.2% in conventional and 47.1% in organic crop management). Venturia Schrottky was highlighted as superabundant, super frequent and constant (46.4% of the specimens) in conventional cultivation. In organic cultivation, Eiphosoma Cresson (15.6% of the specimens), Venturia (15.1%), Polycyrtidea Viereck (7%), Stethantyx Townes (6%), Enicospilus Stephens and Diapetimorpha Viereck (both 5.5%), Polycyrtus Spinola and Podogaster Brullé (both 5%) were more abundant, more frequent and constant. The observed differences reflect the type of crop management. Considering that organic crop management do not use agrochemicals, there is a greater diversification of the landscape. On the other hand, a reduction in richness and abundance has been observed in conventional crop management, due to its greater alteration and uniformity of the landscape. This study evidences a high number of rare, less frequent and accidental genera, and reveals the predominant groups in each crop cultivation system.