Aroplectrus dimerus (Hymenoptera: Eulophidae), Ectoparasitoid of the Nettle Caterpillar, Oxyplax pallivitta (Lepidoptera: Limacodidae): Evaluation in the Hawaiian Islands

The stinging nettle caterpillar, Oxyplax (syn. Darna) pallivitta (Lepidoptera: Limacodidae), is a serious invasive pest of agricultural products and a health hazard on the Hawaiian Islands first discovered in 2001. Nursery workers and homeowners have been stung by the caterpillars while handling their plants, especially rhapis palms (Rhapis sp.). Throughout its invaded range, it causes widespread damage, including the many cultivated and native palm species that have grown in Hawaii. Larvae contain urticating hairs that secrete a toxin, causing painful skin swelling and irritation on contact. Horticulture and nursery products impacted by the limacodid pest are estimated at $84.3 million (2018 value). Suppression efforts with pesticides and lure traps were ineffective, and the moth population continued to spread to major Hawaiian Islands (Hawaii, Kauai, Maui, Oahu). The introduction of specific biological control agents from the native region was thought to be the long-term solution for this invasive pest. Initial exploration in Indonesia and Thailand resulted in the introduction of a pupal ectoparasitoid, Nesolynx sp. (Hymenoptera: Eulophidae: Tetrastichinae), that was not specific. The oriental wasp, Aroplectrus dimerus Lin (Hymenoptera: Eulophidae: Eulophinae), idiobiont gregarious ectoparasitoid of the stinging nettle caterpillar, was introduced from Taiwan in 2004 for host specificity studies and biocontrol in Hawaii. Host range testing showed the parasitoid attacked only limacodid species, and it was approved for field release in 2010. The parasitoid identity, host specificity under containment facility conditions, reproductive performance, and colonization on the major infested sites were assessed. A total of 13,379 parasitoids were colonized on 162 release sites on four Hawaiian Islands. Evaluations were conducted using field surveys of larvae, pupal counts, and male lure traps. Field parasitism was thoroughly investigated on Oahu Island, averaging 18.9 ± 5.6% of 3923 collected larvae during 2010-2023. The numbers of male moths caught/trap/month were significantly reduced on Oahu Island (p < 0.05). Recently, the hyperparasitoid, Pediobius imbreus Walker (Hymenoptera: Eulophidae: Entedoninae), was detected, reducing the efficiency of A. dimerus in the field. The mean hyperparasitism of A. dimerus pupae was 27.3 ± 7.6% on Oahu Island. There was no detailed biological assessment for A. dimerus or its field evaluation available in scientific literature. Results were discussed regarding the potential use of A. dimerus in biocontrol elsewhere if the stinging nettle caterpillar was invaded in the future.

Hymenopteran parasitoids reared from European gall midges (Diptera, Cecidomyiidae)

We report the results of investigations 2010 through 2023 of hymenopteran parasitoids associated with gall midges in Europe. A total of 242 collections of gall midges were made, from each of which one to several parasitoid species emerged, resulting in ca. 200 recorded parasitoid species and 267 host-parasitoid interaction records. The parasitoid families involved were Eulophidae (63 species), Platygastridae (56 species), Torymidae (34 species), Pteromalidae (31 species), Ceraphronidae (5 species), Eupelmidae (4 species), Eurytomidae (2 species) and Encyrtidae (1 species). As many as 159 interactions are reported for the first time, significantly enlarging our knowledge of gall midge - parasitoid interactions on the species level. Even more interesting, 51 host records are for parasitoid species for which no host was previously known. Similarly, 28 species of gall midge are reported as host to named parasitoids for the first time. Additionally, 91 parasitoid records were the first for the country in question. Differences between the rearing methods applied and their suitability for recording species with contrasting life histories, are discussed.

Reproductive Parameters and Host Specificity of Eurytoma erythrinae (Hymenoptera: Eurytomidae), a Biological Control Agent of the Erythrina Gall Wasp, Quadrastichus erythrinae (Hymenoptera: Eulophidae)

Eurytoma erythrinae Gates & Delvare (Hymenoptera: Eurytomidae) is an important biological control agent of the erythrina gall wasp (EGW), Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae), an invasive species likely originating in eastern Africa that is a threat to Erythrina trees in Hawaii and worldwide. Thousands of Erythrina trees in Hawaii have succumbed to EGW since 2005 and died within a few years of infestation. The endemic wiliwili tree, Erythrina sandwicensis, an important component of Hawaii's dry forests and one of few deciduous native trees, were severely impacted by this wasp. Early during the invasion by EGW it became evident that the endemic species may be driven to extinction, and exploration programs for natural enemies of the EGW started in December 2005. East Africa was selected as the starting point for natural enemy exploration owing to high native Erythina species richness. Several gall formers were found in Tanzania and a putative color variant type of Q. erythrinae was detected in association with three ectoparasitoids. During January 2006, the dominant parasitoid of this gall former was introduced to Hawaii and described as the new species, E. erythrinae. It was found in Ghana and South Africa attacking other gall wasp species on Erythrina. Eurytoma erythrinae was a voracious ectoparasitoid feeding as a predator on 1-5 adjacent EGW immatures to complete its development. Host specificity studies that included seven nontarget gall-forming species showed no evidence of attraction or parasitism by this parasitoid. Mean ± SEM longevity of host-deprived females (40.4 ± 2.2 days) was significantly higher than males (20.5 ± 1.1 days). Host feeding enhanced longevity of ovipositing females (51.3 ± 1.5 days). Female E. erythrinae is synovigenic, with high egg-maturation rate. Peak fecundity (105-239 offspring/female), host feeding biology, short life cycle (18.4 ± 0.1 days), and synchronization with the host were additional desirable attributes of this species. The parasitoid was approved for field release in Hawaii in November 2008. A total of 3998 wasps were distributed on six Hawaiian Islands, with establishment in less than a year. Impacts on high density infestations of EGW were sufficient to prevent tree deaths. Limited rates of parasitism on low-density galled leaves, flowers, and seedpods necessitated the consideration for releasing a second parasitoid, Aprostocetus nitens Prinsloo & Kelly (Hymenoptera: Eulophidae). We report on the reproductive characteristics and host specificity of E. erythinae that could be of importance for classical biocontrol programs in areas with an EGW problem.

Few indirect effects of baculovirus on parasitoids demonstrate high compatibility of biocontrol methods against Tuta absoluta

BACKGROUND

Combining different biocontrol agents, particularly micro- and macroorganisms, can contribute to new and sustainable pest control approaches. Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most destructive pests of solanaceous crops. An emerging management strategy consists of biological control using microbial insecticides such as baculoviruses, but with limited efficacy. Thanks to their high target specificity, baculoviruses can be used simultaneously with natural enemies such as parasitoids for improved control of T. absoluta. However, potential indirect nontarget effects of baculoviruses on parasitoids can result from overlapping resource requirements. We assessed whether ovipositing parasitoid females discriminated against virus-treated hosts and examined the outcome of within-host competition between the hymenopteran parasitoids Necremnus tutae (Reuter) (Eulophidae) and Dolichogenidea gelechiidivoris Marsch (Braconidae), and the Phthorimaea operculella granulovirus (PhopGV, Baculoviridae) that infects T. absoluta larvae.

RESULTS

Female D. gelechiidivoris discriminated against virus-treated hosts, whereas N. tutae did not. We found few indirect virus-related effects depending on the species, the sex, and the time of virus treatment. Effects were ambivalent for D. gelechiidivoris offspring and ranged from increased male longevity when infection occurred before parasitization to reduced emergence and male longevity when infection occurred after parasitization. N. tutae offspring showed a longer development time and shorter male longevity when they developed in virus-treated hosts.

CONCLUSION

The virus had a low impact on parasitoid offspring. In rare cases, adverse effects were detected; however, the low magnitude of these effects is unlikely to reduce the fitness of parasitoid offspring, therefore both parasitoids seem compatible with the baculovirus for control of T. absoluta. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Demographics and host-kill parameters of Diglyphus horticola Khan against Chromatomyia horticola (Goureau)

The pea leafminer, Chromatomyia horticola (Goureau) (Diptera: Agromyzidae) is a polyphagous and serious pest of peas. In India, this pest is attacked by many parasitoids and among them Diglyphus horticola Khan (Hymenoptera: Eulophidae) is an important one, however, demographics and pest-kill potential of this parasitoid has not been studied so far. This study presents the first report on its demographics and pest-kill potential on C. horticola. The parasitoid showed three modes of host-killing behaviour viz. host-feeding, parasitism and host-stinging. The parasitoid females killed more number of hosts by parasitism than host-feeding or host-stinging. The pre-adult survival, net reproductive rate, intrinsic rate of increase (r_m) and finite rate of increase (λ) were higher on the 5-days old host larvae than those reared on the 3-days old larvae. Demographics and pest-kill parameters of D. horticola were also better on 5-days old host larvae than on 3-days old host larvae. Based on the study, D. horticola appeared to be a promising biocontrol agent for the suppression of C. horticola in peas and could be promoted through conservation biological control. Further studies are required to standardize the mass production protocol and release rates to use the parasitoid by augmentation.

Selectivity of Insecticides to a Pupal Parasitoid, Trichospilus diatraeae (Hymenoptera: Eulophidae), of Soybean Caterpillars

Selectivity is an important aspect of modern insecticides to be able to target pests whilst maintaining beneficial entomofauna in the crop. The present objective was to assess the selectivity of different insecticides for the pupal parasitoid of soybean caterpillars, i.e., Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae). Acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin at the highest recommended concentrations for the soybean looper Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), as well as water in the control, were used against the pupal parasitoid T. diatraeae. The insecticides and the control were sprayed on the soybean leaves, which were left to dry naturally and placed in cages with T. diatraeae females in each one. Survival data were submitted to analysis of variance (ANOVA) and the means were compared using Tukey's HSD test (α = 0.05). Survival curves were plotted according to the Kaplan-Meier method, and the pairs of curves were compared using the log-rank test at 5% probability. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival, while deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity and acephate was highly toxic, causing 100% mortality in the parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae and could be used in IPM programs.

Environmental Factors Drive Chalcid Body Size Increases with Altitudinal Gradients for Two Hyper-Diverse Taxa

Body size is the most essential feature that significantly correlates with insects' longevity, fecundity, metabolic rate, and sex ratio. Numerous biogeographical rules have been proposed to illustrate the correlation between the body sizes of different taxa and corresponding geographical or environmental factors. Whether the minute and multifarious chalcids exhibit a similar geographical pattern is still little known. In this research, we analyzed morphological data from 2953 specimens worldwide, including the two most abundant and diverse taxa (Pteromalidae and Eulophidae), which are both composed of field-collected and BOLD system specimens. We examined forewing length as a surrogate of body size and analyzed the average size separately for males and females using two methods (species and assemblage-based method). To verify Bergmann's rule, we included temperature, precipitation, wind speed and solar radiation as explanatory variables in a generalized linear model to analyze the causes of the size variation. We found that there was an increasing trend in the body size of Pteromalidae and Eulophidae with altitude. The optimal Akaike information criterion (AIC) models showed that larger sizes are significantly negatively correlated with temperature and positively correlated with precipitation, and the possible reasons for this variation are discussed and analyzed.

Transcriptome Analysis and Identification of Chemosensory Genes in Baryscapus dioryctriae (Hymenoptera: Eulophidae)

Baryscapus dioryctriae is a pupal endoparasitoid of many Pyralidae pests and has been used as a biocontrol agent against insect pests that heavily damage the cone and seed of the Korean pine. The olfactory system of wasps plays an essential role in sensing the chemical signals during their foraging, mating, host location, etc., and the chemosensory genes are involved in detecting and transducing these signals. Many chemosensory genes have been identified from the antennae of Hymenoptera; however, there are few reports on the chemosensory genes of Eulophidae wasps. In this study, the transcriptome databases based on ten different tissues of B. dioryctriae were first constructed, and 274 putative chemosensory genes, consisting of 27 OBPs, 9 CSPs, 3 NPC2s, 155 ORs, 49 GRs, 23 IRs and 8 SNMPs genes, were identified based on the transcriptomes and manual annotation. Phylogenetic trees of the chemosensory genes were constructed to investigate the orthologs between B. dioryctriae and other insect species. Additionally, twenty-eight chemosensory genes showed female antennae- and ovipositor-biased expression, which was validated by RT-qPCR. These findings not only built a molecular basis for further research on the processes of chemosensory perception in B. dioryctriae, but also enriched the identification of chemosensory genes from various tissues of Eulophidae wasps.

Characterization of the mitochondrial genome of Tetrastichus howardi (Olliff 1893) (Hymenoptera: Eulophidae)

The mitochondrial genome has been widely used in the study of phylogeny and species-level evolution. Here, we sequenced and analyzed the full mitogenome of Tetrastichus howardi, an important natural enemy of many lepidopteran pests. The complete mitochondrial genome has 14,791 nucleotides, containing 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and a partial control region. All the 13 PCGs started with typical ATN (ATA, ATG, and ATT) codon. Among 13 PCGs, nine genes terminated with the stop codon TAA and four genes terminated with T. Our study provides information on comparative mitogenomics of Eulophidae.

Complete mitochondrial genome of a predominant parasitoid, Necremnus tutae (Hymenoptera: Eulophidae) of the South American tomato leafminer Tuta absoluta (Lepidoptera: Gelechiidae)

The complete mitochondrial genome of a predominant parasitoid, Necremnus tutae (Hymenoptera: Eulophidae) (GenBank accession number MT916846) is 15,252 bp in length, and contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes, and an A + T-rich region. The overall base composition is 38.86% for A, 7.14% for C, 8.57% for G, and 45.43% for T, with a high AT bias of 84.29%. ATA, ATT, ATG were initiation codons and TAA and T were termination codons. All the 22 tRNAs displayed a typical cloverleaf secondary structure, except for trnS₁ and trnR which lacked the dihydrouracil (DHU) arm. Phylogenetic analyses were performed using 13 PCGs showed that N. tutae is closely related to Tenthredo tienmushana, which in accordance with the traditional classification.

Female-Produced Sex Pheromone of Tetrastichus planipennisi, a Parasitoid Introduced for Biological Control of the Invasive Emerald Ash Borer, Agrilus planipennis

The Asian eulophid wasp Tetrastichus planipennisi is being released in North America as a biocontrol agent for the emerald ash borer (Agrilus planipennis), a very destructive invasive buprestid beetle that is devastating ash trees (Fraxinus spp.). We identified, synthesized, and tested a female-produced sex pheromone for the wasp. The key component eliciting behavioral responses from male wasps in flight tunnel bioassays was identified as (6S,10S)-(2E,4E,8E)-4,6,8,10-tetramethyltrideca-2,4,8-triene. Female specificity was demonstrated by gas chromatographic (GC) comparison of male and female volatile emissions and whole body extracts. The identification was aided by coupled gas chromatography/mass spectrometry analysis, microchemical reactions, NMR, GC analyses with a chiral stationary phase column, and matching GC retention times and mass spectra with those of synthetic standards. The tetramethyl-triene hydrocarbon was synthesized as a mixture of two enantiomeric pairs of diastereomers, and as the pure insect-produced stereoisomer. In flight-tunnel bioassays, males responded to both the natural pheromone and the chiral synthetic material by upwind flight and landing on the source. In contrast, the mixture of four stereoisomers was not attractive, indicating that one or more of the "unnatural" stereoisomers antagonized attraction. Field trials, using yellow pan traps baited with natural pheromone, captured significantly more male wasps than control traps over a four week trial. The identified pheromone could increase the efficiency and specificity of the current detection methods for Tetrastichus planipennisi and aid in the determination of parasitoid establishment at release sites.

Color Preference of Three Parasitoids Imported to the Americas for the Biological Control of the Coffee Berry Borer (Curculionidae: Scolytinae)

The African parasitoids Cephalonomia stephanoderis Waterston (Bethylidae: Hymenoptera), Prorops nasuta Betrem (Bethylidae: Hymenoptera), and Phymastichus coffea LaSalle (Eulophidae: Hymenoptera) are biological control agents of the coffee berry borer (Coleoptera: Curculionidae). In this study, we investigated in laboratory the female behavioral responses of these parasitoids to 14 different wavelengths (340-670 nm) against a control (570 nm, yellow). When nonchooser females were included in the analysis, none parasitoids species showed a preference between 340, 350, 370, 460, 490, 520, 540, 590, 640, and 650 nm with respect to the control wavelength. In contrast, the three species of parasitoids were more attracted to wavelengths of 380, 400, and 420 nm than the control wavelength. Phymastichus coffea and P. nasuta were more attracted to the wavelength of 400 and 420 nm compared to C. stephanoderis. At 380 nm, P. coffea and C. stephanoderis wasps showed the higher responses in comparison to P. nasuta females. When nonchooser wasps were excluded from the analysis, we observed other differences among the parasitoid species. For instance, P. coffea were more attracted to 490-540 nm than to 570 nm, whereas the bethylids did not discriminate between 490-540 nm or 570 nm. Our results are discussed in relation to possible implications associated with the vision of these parasitoid species.

Mitochondrial genome of Tamarixia radiata (Hymenoptera: Chalcidoidea: Eulophidae) and phylogenetic analysis

Tamarixia radiata plays an important role in biological control of the psyllid Diaphorina citri Kuwayama, vector of the huanglongbing (HLB). In this study, we sequenced and analyzed the mitochondrial genome (mitogenome) of T. radiata, the first mitogenome of species in the family Eulophidae. This mitogenome was 14,752 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA unit genes (rRNAs). All 13 PCGs were initiated by the ATN (ATG, ATT, and ATA) codon. Twelve PCGs terminate with the stop codon TAA or TAG except for nad1 which end with the incomplete codon T-. Phylogenetic analysis showed that T. radiata got together with three Pteromalidae species, indicating the close relationship of Eulophidae and Pteromalidae.

Comparing Potential as Biocontrol Agents of Two Neotropical Parasitoids of Liriomyza sativae

We evaluated the potential of two parasitoids as biocontrol agents of Liriomyza sativae Blanchard in northeastern Brazil. The two species were the koinobiont larval-pupal endoparasitoid Phaedrotoma scabriventris Nixon (Braconidae) and the idiobiont larval endoparasitoid Chrysocharis vonones (Walker) (Eulophidae). The biological parameters evaluated were survivorship, parasitism, and host-feeding, at 25 and 30°C. Differences between the species were observed at 25°C, but not at 30°C. At 25°C, the total parasitism for P. scabriventris (196.1 ± 17.7) and C. vonones (176.6 ± 7.24) was similar and with higher values compared to 30°C, 102.5 ± 8.81 and 89.1 ± 5 66 parasitized larvae, respectively. However, C. vonones showed a 3.97 lower survivorship as well as higher daily parasitism (1.4-fold) and host-feeding means (1.9-fold) than the braconid at 25°C. The results indicate a potential for both natural enemies to be used as biocontrol agents of L. sativae. The differences between species detected at 25°C suggest the best conditions for the application of each parasitoid.

Influence of Density on Interspecific Competition Between Spathius galinae (Hymenoptera: Braconidae) and Tetrastichus planipennisi (Hymenoptera: Eulophidae), Larval Parasitoids of the Invasive Emerald Ash Borer (Coleoptera: Buprestidae)

The outcomes of interspecific interactions between parasitoids depend on a variety of factors. Understanding the influence of these factors is important for classical biological control, where the success of parasitoid releases partly depends on interactions with native and other introduced species. However, results from laboratory experiments may not always reflect those in the field, as densities may be artificially inflated. To mitigate this problem, we examined the effects of multiple densities on interspecific competition between two larval parasitoids of emerald ash borer (Agrilus planipennis Fairmaire): Spathius galinae Belokobylskij and Tetrastichus planipennisi Yang. Parasitoid species were housed individually or together at two different densities, and we measured the effects on percent parasitism and progeny production, before calculating the interaction strengths. We found no significant effects of parasitoid density on percent parasitism, but the effect of competition on parasitism generally was reduced at lower densities. However, there were significant differences in parasitism by species, with S. galinae parasitizing more larvae than T. planipennisi. There were also no significant effects of parasitoid density on the number of progeny produced by each species, though the effect of competition on progeny production was greater at higher densities. Similarly, though, there were significant differences between species in the number of progeny produced. Specifically, T. planipennisi consistently produced larger broods than S. galinae. Our findings complement existing research suggesting that competition between these two species in the field will likely be negligible.

Tetrastischus howardi density and dispersal toward augmentation biological control of sugarcane borer

The number of Tetrastischus howardi (Olliff) females to be released and their dispersion should be known, that way, used D. saccharalis pupae as sentinel host to measure parasitism as function of the release density of the parasitoid and its location in the field. Two sets of trials were run aiming first to define the number of parasitoids to be released and the dispersal of the parasitoid using plots in sugarcane commercial fields, respectively. Pieces of sugarcane stalk holding sentinel pupae were taken to the field and exposed to parasitism in both trials. The parasitoid was released at the rate of 20, 40, 80, and 160 females per sentinel pupa, except for the control plot without releasing. The parasitism rate was calculated based on the recovered pupae after 96 h of exposure time from releasing the parasitoids. The models estimated the best parasitism rate by releasing 102 parasitoids per pupa. In the second trial, sentinel pupae were arranged in five subsequent circles corresponding 4, 8, 12, 16, and 20 m around the central parasitoid releasing point at rate of 4, 8, 12, 16, and 18 pupae per circle. The mean estimated dispersal distance was 7.64 m, with a covering area of 80.07 m². Based on these findings, release of T. howardi is recommended in 125 points per hectare of sugarcane at rate of 102 females per pupa of the pest aiming to achieve homogeneous distribution and parasitism.

Description of a new species of Euderus Haliday from the southeastern United States (Hymenoptera, Chalcidoidea, Eulophidae): the crypt-keeper wasp

A new species of the genus Euderus Haliday, Euderus setsp. n., is described and illustrated from the southeastern United States, where it parasitizes the crypt gall wasp, Bassettia pallida Ashmead, 1896, on live oaks in the genus Quercus (subsection Virentes). This is the 1st species of the genus reported from the southeastern United States to parasitize cynipid gall wasps and the 3rd species of the genus reported to attack cynipids in North America. Modified sections of the identification keys to subgenera and species of Euderus (Yoshimoto, 1971) are included to integrate the new species.

Effects of climate on pine processionary moth fecundity and on its egg parasitoids

Climate change may be affecting the fecundity of phytophagous insects as well as impacting their natural enemies. However, temperature impacts these two insect groups differently, disrupting population regulation mechanisms, and ultimately, possibly culminating in an outbreak of the host. The pine processionary moth (PPM) is one of the most harmful insects of the Mediterranean basin. Not only are PPM larvae harmful to plants, but they are also dangerous to humans because of their urticating hairs. Although some information is available on climate change effects on the PPM, little is known about its potential effects on PPM egg parasitoids, especially on their distribution range or on their role in controlling PPM populations. The aim of this article was to verify the effects of climate on PPM fecundity and on its egg parasitoids. Our results show that climate warming may affect the PPM positively, but not its egg parasitoids. Specifically, during our study mild winters directly favored the PPM, while increasing summer temperatures (over 30°C) also favored the PPM indirectly, by decreasing parasitism rates. We predict that ever‐milder winters will not only favor PPM development, but also encourage it to spread in otherwise previously inhospitable environments.

Karyotypes of parasitic wasps of the family Eulophidae (Hymenoptera) attacking leaf-mining Lepidoptera (Gracillariidae, Gelechiidae)

Karyotypes of eleven parasitoid species of the family Eulophidae were examined, namely, Chrysocharis laomedon (Walker, 1839) (2n = 10), Chrysocharis sp. aff. laomedon (n = 5, 2n = 10), Chrysocharis sp. aff. albipes (Ashmead, 1904) (2n = 12), Mischotetrastichus petiolatus (Erdös, 1961) (n = 6, 2n = 12), Minotetrastichus frontalis (Nees, 1834) (n = 5, 2n = 10), Cirrospilus pictus (Nees, 1834) (2n = 12), Hyssopus geniculatus (Hartig, 1838) (2n = 16), Sympiesis gordius (Walker, 1839) (2n = 12), S. sericeicornis (Nees, 1834) (2n = 12), Pnigalio agraules (Walker, 1839) (2n = 12 + 0-2B) and Pnigalio gyamiensis Myartseva & Kurashev, 1990 (2n = 12 + 0-6B) reared from Phyllonorycter acerifoliella (Zeller, 1839), Ph. apparella (Herrich-Schäffer, 1855), Ph. issikii (Kumata, 1963) (Gracillariidae) and Chrysoesthia sexguttella (Thunberg, 1794) (Gelechiidae). Chromosome sets of all species except P. agraules and P. gyamiensis were studied for the first time. B chromosomes were detected in the two latter species; in P. gyamiensis, the maximum number of B chromosomes represents the highest value known for parasitic wasps to date.

Temperature-dependent development of two neotropical parasitoids of Liriomyza sativae (Diptera: Agromyzidae)

We studied two species of neotropical parasitoids that occur naturally in northeastern Brazil and are associated with Liriomyza sativae (Blanchard): Opius (Gastrosema) scabriventris Nixon (Hymenoptera: Braconidae) and Chrysocharis vonones (Walker) (Hymenoptera: Eulophidae). We evaluated the influence of seven temperatures on the duration of the egg-adult period and on the survivorship of the immature stages of the parasitoids. A temperature increase from 15 to 30°C shortened the egg-adult period of O. scabriventris and C. vonones. However, at 32°C, the developmental time for the braconid was prolonged, and no difference was observed for the eulophid, compared with 30°C. The highest temperature, 35°C, proved to be lethal for both species. At 15°C, C. vonones pupal survivorship was drastically reduced, whereas that of O. scabriventris was unaffected. At most temperatures, the eulophid had an egg-adult period shorter than or similar to the braconid, except at 15°C. The threshold temperature (Tt) of the egg-adult period for O. scabriventris was 7.3°C with a thermal constant (K) of 257.1 degree days (DD). For C. vonones the Tt was 7.4°C for the total cycle and 6.2°C for the pupal stage, with a thermal constant of 246.3 and 140.3 DD, respectively. These data allow an estimate of 29.4 annual generations for O. scabriventris and 30.5 for C. vonones in a melon production region in northeastern Brazil, values that are equivalent to 4.9 and 6.0 more generations than the host. These results demonstrate that both species have potential for application in biological control programs against the leafminer fly L. sativae.

The preimaginal stages of Pnigalio gyamiensis Myartseva & Kurashev, 1990 (Hymenoptera, Eulophidae), a parasitoid associated with Chrysoesthia sexguttella (Thunberg) (Lepidoptera, Gelechiidae)

The larval instars of Pnigalio gyamiensis Myartseva and Kurashev are described in detail for the first time. This species is a larval-pupal ectoparasitoid of Chrysoesthia sexguttella (Thunberg) (Lepidoptera, Gelechiidae), which forms leaf mines in the plant Chenopodium album L. (Caryophyllales: Amaranthaceae). The female of Pnigalio gyamiensis lays a single egg on the skin of the host larva or nearby it, without any significant preference for a particular variant. The presence of long hairs on its body provides the newly-hatched first larval instar with high mobility. Some peculiarities in this parasitoid-host relationship are described.

Comparative cytogenetic study on two species of the genus Entedon Dalman, 1820 (Hymenoptera, Eulophidae) using DNA-binding fluorochromes and molecular and immunofluorescent markers

Karyotypes of Entedon cionobius Thomson, 1878 and Entedon cioni Thomson, 1878 (Hymenoptera: Eulophidae) were studied using DNA-binding ligands with different base specificity (propidium iodide, chromomycin A3, methyl green and DAPI; all these ligands, except for the last one, were used for the first time in parasitic wasps), C-banding, fluorescence in situ hybridization (FISH) with a 45S rDNA probe and 5-methylcytosine immunodetection. Female karyotypes of both species contain five pairs of relatively large metacentric chromosomes and a pair of smaller acrocentric chromosomes (2n = 12). As in many other Hymenoptera, males of both Entedon Dalman, 1820 species have haploid chromosome sets (n = 6). Fluorochrome staining revealed chromosome-specific banding patterns that were similar between the different fluorochromes, except for the CMA3- and PI-positive and DAPI-negative band in the pericentromeric regions of the long arms of both acrocentric chromosomes. The obtained banding patterns were virtually identical in both species and allowed for the identification of each individual chromosome. C-banding revealed a pattern similar to DAPI staining, although centromeric and telomeric regions were stained more intensively using the former technique. FISH detected a single rDNA site in the same position on the acrocentric chromosomes as the bright CMA3-positive band. Immunodetection of 5-methylcytosine that was performed for the first time in the order Hymenoptera revealed 5-methylcytosine-rich sites in the telomeric, centromeric and certain interstitial regions of most of the chromosomes.

Paracrias pluteus (Hymenoptera, Eulophidae) in Brazil: new distribution and host records, and with a new host group for Paracrias

Bruchines damage agricultural crops and trees, reducing the quantity and quality of the seeds. The aim of this study is to record, for the first time, Paracrias pluteus as a parasitoid on the immature stages of Sennius spodiogaster and Sennius cupreatus on seeds of Melanoxylon brauna in Teixeiras, Minas Gerais State, Brazil. Paracrias pluteus is a parasitoid without previous host records and known only from Costa Rica. Specimens obtained in this study add to knowledge of the biology of Paracrias species with a new host group (Chrysomelidae: Bruchinae), and the first host record and a new distribution for Paracrias pluteus.