Ecological and morphological characteristics of endoparasitoids on Elcysma westwoodii (Vollenhoven) (Lepidoptera: Zygaenidae)

Six species of insect endoparasitoids were identified from Elcysma westwoodii, which is the most damaging lepidopteran pest of Prunus yedoensis. From Hymenoptera, two species were identified: a species in Braconidae and Charops striatus in Ichneumonidae. From Diptera, there were four species in Tachinidae: Compsilura concinnata, Exorista sp., Pales sp. and Tachinidae spp. The parasitic ratio was 4.86% (45 of 926 larvae). The hymenopterans were parasitic on 31 individuals of E. westwoodii (68.9%) and the dipterans were parasitic on 14 individuals (31.1%). It was found that parasitoids from the larvae of E. westwoodii were all either endoparasitoids or larval parasitoids. However, Exorista sp. of Tachinidae was found to be either a larval parasitoid or larval-pupal parasitoid. Additionally, all the identified parasitoids were solitary parasitoids, as only one parasite occurred in a larva of E. westwoodii. Because the larva of E. westwoodii eats and molts after it is parasitized, all the parasitoids were identified as koinobionts. There were no big differences in morphological characteristics and life histories between C. striatus and C. concinnata. However, for Exorista sp. and Pales sp., males took 3–5 days longer to emerge from their pupae and had remarkably longer body lengths than females.     

Effect of host age on life cycle and morphological characteristics of Glyptapanteles liparidis (Hymenoptera: Braconidae), a parasitoid of Acronicta rumicis (Lepidoptera: Noctuidae)

The life cycle of Glyptapanteles liparidis was 23.75 ± 1.26, 21.95 ± 2.44 and 20.83 ± 0.78 days when fed on the first, second and third instar larvae of Acronicta rumicis, respectively. Although insufficient numbers hindered statistical analysis, the life cycle of G. liparidis appeared to be shortest, 19 days, when fed on fourth instar larvae. The life cycle of G. liparidis tends to shorten as the larvae of A. rumicis fed upon are more advanced. The body length, forewing length and head capsule width of female G. liparidis fed on first instar larvae of A. rumicis were greater than those of males, while the antennae of males were longer than those of females. When fed on second instar larvae, there was no difference in body length and head capsule width between males and females, but the male antennae were longer than the female, and the female forewings were longer than the male. When fed on third instar larvae, there was no significant difference in head capsule width between the sexes, but female body length and forewing length were greater than the male, and the male antennae were longer than the female. On the whole, females were bigger than males in terms of body length and forewing length, while antennae of the males were longer than those of the females. There was no difference in head capsule width between males and females. Body length, antenna length, forewing length and head capsule width of male and female G. liparidis were relatively larger when fed on first instar larvae of A. rumicis than when fed on second and third instar larvae.     

Interaction of Acronicta rumicis (Lepidoptera: Noctuidae) and its larval parasitoid, Glyptapanteles liparidis (Hymenoptera: Ichneumonidae)

As a result of parasitism by Glyptapanteles liparidis in the first, second, third and fourth instar larvae of Acronicta rumicis, the mortality of each larval stage was found to be 46.67, 90, 71 and 16.67%, respectively. The mortality was highest when G. liparidis parasitized the second and third instar larvae. The difference in mortality between the parasitized group and the control group was 72.14% in the second instar larvae. With regards to the food consumption of the parasitized larvae, the first and second instar larvae consumed 6495.58 ± 646.52 mm² (leaf surface) and 7951.12 ± 4167.36 mm², respectively, while the third and fourth larvae consumed 13 826.77 ± 3396.66 mm² and 18 599.85 mm², respectively, showing that food consumption increased with instar stages of the host larvae. The clutch size of G. liparidis increased in relation to the instar stages of the host: it was 25.25 ± 7.89, 48.65 ± 53.75, 91.09 ± 44.52 and 114 individuals when they were fed with the first, second, third and the fourth instar larvae of the host, respectively.     

Endoparasitoids of larval Anomis privata (Lepidoptera: Noctuidae), major pest of Hibiscus syriacus (Columniferae: Malvaceae)

Endoparasitoids of Anomis privata larvae include five species in three families of two orders. In this work, two species of Hymenoptera Braconidae (Cotesia sp., Microplitis sp.), one species of Ichneumonidae (Mesochorus vittator) and two species of Diptera Tachinidae (Exorista (Podotachina) sorbillans, Timavia amoena) were investigated. Of the 261 larvae of A. privata examined, 32 had a parasite, so the rate of parasitism was 12.26%. Parasitism by taxon was the highest, at 10.35% (27 individuals), in Cotesia sp. in Hymenoptera Braconidae. Parasitoids of Braconidae and Ichneumonidae were larval parasitoids. A parasitic insect of Tachinidae was a larva–pupal parasitoid. Solitary parasitoids included Microplitis sp. in Braconidae and E. sorbillans in Tachinidae. Gregarious parasitoids included Cotesia sp. in Braconidae, M. vittator in Ichneumonidae and T. amoena in Tachinidae. There was also a multiparasitoid (T. amoena) and two superparasitoids (Cotesia sp., M. vittator). A larva of A. privata sought feed even after it was parasitized every parasitoid investigated in this study, so five species of parasitoids were all koinobiont.     

Convergence and Divergence in Direct and Indirect Life-History Traits of Closely Related Parasitoids (Braconidae: Microgastrinae)

Closely related species in nature often show similarities in suites of direct and indirect traits that reveal aspects of their phylogenetic history. Here we tested how common descent affects trait evolution in several closely related parasitoid species in the genera Cotesia and Microplitis (Hymenoptera: Braconidae: Microgastrinae) by comparing development, resource use and allocation into reproduction and maintenance. Parasitoids in these genera exhibit traits, like haemolymph feeding as larvae and external pupation that are rare in most parasitoid lineages. The growth of parasitized hosts was reduced by 90 % compared with healthy hosts, and maximum host size depended to a large extent on adult parasitoid size. Development time was longer in the more generalist parasitoids than in the specialists. Adult body mass was sexually dimorphic in all Cotesia species, with females being larger, but not in Microplitis spp. In contrast, in one of the Microplitis species males were found to be the larger sex. Egg load dynamics during the first 6 days after emergence were highly variable but egg number was typically higher in Cotesia spp. compared to Microplitis spp. Longevity in the various species was only greater in female than in male wasps in two Microplitis sp. There was a clear inverse relationship between resource use and allocation, e.g. maximum egg load and longevity, in these parasitoids. Our results reveal that adaptation to constraints imposed by host quality and availability has resulted in trait convergence and divergence at the species, genus and subfamily level.     

Sex ratio of Nysius huttoni White (Hemiptera: Lygaeidae) in field and laboratory populations

Abstract

We studied the parasitoids of three insect seed predators of the mast-seeding genus Chionochloa spp. (snow tussocks) at Mt Hutt, New Zealand. Megacraspedus calamogonus (Lepidoptera: Gelechiidae) is parasitised by four species, three Hymenoptera (Zealachertus tortriciphaga [Eulophidae], Diadegma sp. [Ichneumonidae] and Dolichogenidea sp. [Braconidae]) and one Diptera (Uclesiella sp. [Tachinidae]). Diplotoxa similis (Diptera: Chloropidae) is parasitised by Callitula sp. (Hymenoptera: Pteromalidae). Eucalyptodiplosis chionochloae (Diptera: Cecidomyiidae) is parasitised by two Hymenoptera, Gastrancistrus sp. (Pteromalidae) and Zelostemma chionochloae (Platygastridae); all three species have extended diapause. Overall parasitism was 68.5% in M. calamogonus, 1% in D. similis, and 41% in E. chionochloae. Such parasitism in M. calamogonus and E. chionochloae may reduce seed predation in Chionochloa and alter the selective benefit of mast seeding (predator satiation) to the plant. However, seed predation is still high at many sites, so some of the seed predators and parasitoids may be food-limited (bottom-up regulation).     

Overwintering strategy of endoparasitoids in Chilo suppressalis: a perspective from the cold hardiness of a host

Although parasitoids ultimately kill their host, koinobiont parasitoids must protect not only themselves but also their hosts against extreme environments. In this study, the parasitism rate of Chilo suppressalis Walker (Lepidoptera: Pyralidae) was investigated, and the average body weights, supercooling points, and concentrations of glycerol (acting as a cryoprotectant) in the hemolymph were compared between parasitized and non‐parasitized larvae. Five species of koinobiont endoparasitoids parasitized the overwintering C. suppressalis larvae and the total parasitism rate was 47.6% (n = 1 537). Average body weight of parasitized larvae was significantly lower than that of non‐parasitized larvae, and the parasitism rate of the lighter group (20–30 mg) was highest. The supercooling point of parasitized C. suppressalis larvae (?15.7 ± 0.3 °C) was significantly lower than that of the non‐parasitized larvae (?14.3 ± 0.2 °C). In addition, supercooling points were not correlated with body weights between parasitized and non‐parasitized larvae, indicating that cold hardiness of parasitized larvae was enhanced by endoparasitoids. Furthermore, the concentration of glycerol in the hemolymph was significantly higher in parasitized larvae (205.0 ± 7.1 μmol ml^?1) than in non‐parasitized larvae (169.8 ± 14.4 μmol ml^?1), which suggests that the mechanism that decreases the supercooling point of parasitized larvae was associated with glycerol. All these results indicated that the cold hardiness of parasitized C. suppressalis larvae was enhanced by their endoparasitoids, which benefitted overwintering endoparasitoids.     

Feeding by common heterotrophic protists on the mixotrophic alga Gymnodinium smaydae (Dinophyceae), one of the fastest growing dinoflagellates

Gymnodinium smaydae is one of the fastest growing dinoflagellates. However, its population dynamics are affected by both growth and mortality due to predation. Thus, feeding by common heterotrophic dinoflagellates Gyrodinium dominans , Gyrodinium moestrupii , Oblea rotunda , Oxyrrhis marina , and Polykrikos kofoidii , and the naked ciliate Pelagostrobilidium sp. on G. smaydae was investigated in the laboratory. Furthermore, growth and ingestion rates of O. marina , G. dominans , and Pelagostrobilidium sp. on G. smaydae in response to prey concentration were also determined. Oxyrrhis marina , G. dominans , G. moestrupii , and Pelagostrobilidium sp. were able to feed on G. smaydae , but P. kofoidii and O. rotunda did not feed on this dinoflagellate. The maximum growth rate of O. marina on G. smaydae was 0.411 per day. However, G. smaydae did not support the positive growth of Pelagostrobilidium sp. The maximum ingestion rates of O. marina and Pelagostrobilidium sp. on G. smaydae were 0.27 and 6.91 ng C · predator^?1 · d^?1, respectively. At the given mean prey concentrations, the highest growth and ingestion rates of G. dominans on G. smaydae were 0.114 per day and 0.04 ng C · predator^?1 · d^?1, respectively. The maximum growth and ingestion rates of O. marina on G. smaydae are lower than those on most of the other algal prey species. Therefore, O. marina may be an effective predator of G. smaydae , but G. smaydae may not be the preferred prey for supporting high growth of the predator in comparison to other species as inferred from a literature survey.     

Larval and pupal parasites ofLymantria dispar and notes on parasites of otherLymantriidae [Lep.] in Poland 1975

Larvae and pupae ofLymantria dispar (L.) were collected periodically from infestations on Linden trees at Nieborów near Skierniewice and at Alexandrowa, south of Poznan, Poland during May–July 1975. The following parasites were recovered:Braconidae: Apanteles liparidis (Bouché),A. melanoscelus (Ratzeburg),A. porthetriae Muesebeck,Meteorus pulchricornis (Wesmael);Ichneumonidae: Coccygomimus instigator (F.),Hyposoter tricoloripes (Viereck),Phobocampe n. sp.,P. disparis (Viereck);Tachinidae: Blepharipa pratensis (Meigen),Blondelia nigripes (Fallén),Carcelia separata (Rondani),Compsilura concinnata (Meigen),Parasetigena silvestris (Robineau-Desvoidy),Palexorista sp. Similar but less extensive collections were made of larvae ofOrgyia antiqua (L.). These yieldedApanteles sp.,A. melanoscelus, Tramosema rostrale (Brischke),Meloborus sp.,B. nigripes andP. silvestris; larvae ofLeucoma salicis (L.) yieldedA. melanoscelus andMeteorus versicolor (Wesmael). OnlyBlondelia sp. was recovered from the few larvae ofPorthesia similis (Fuessly) collected.

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Résumé Des chenilles et des chrysalides deLymantria dispar (L.) ont été ramassées périodiquement en Pologne de mai à juillet 1975 dans les peuplements de tilleuls infestés, à Nieboróv près de Skierniewice et à Alexandrowa, au sud de Poznan. Les parasites obtenus ont été les suivants: lesBraconidae: Apanteles liparidis (Bouché),A. melanoscelus (Ratzeburg),A. porthetriae Muesebeck,Meteorus pulchricornis (Wesmael); lesIchneumonidae: Coccygomimus instigator (F.),Hyposoter tricoloripes (Viereck),Phobocampe n. sp.,P. disparis (Viereck); lesTachinidae: Blepharipa pratensis (Meigen),Blondelia nigripes (Fallén),Carcelia separata (Rondani),Compsilura concinnata (Meigen),Parasetigena silvestris (Robineau-Desvoidy), etPalexorista sp. Des collectes du même type mais moins importantes de chenilles d’Orgyia antiqua (L.) ont permis d’obtenir les parasites suivants:Apanteles sp.,A. melanoscelus. Tranosema rostrale (Brischke),Meloborus sp.,B. nigripes, etP. silvestris. Des chenilles deLeucoma salicis (L.) ont donnéA. melanoscelus etMeteorus versicolor (Wesmael). SeulBlondelia sp. a été obtenu à partir de quelques chenilles dePorthesia similis (Fuessly).

     

Optimization of diet and culture environment for larvae and juvenile freshwater pearl mussels,Hyriopsis (Limnoscapha) myersiana Lea, 1856

Summary

Culture of the freshwater pearl mussel, Hyriopsis (Limnoscapha) myersiana, was carried out in three consecutive steps: (1) culture of glochidia larvae in artificial media, (2) rearing the early juveniles (0–120 days old) in a nursery, and (3) rearing the juveniles (120–360 days old) in an earthen pond. The percentage survival of glochidia in standard tissue culture medium (M199) supplemented with common carp plasma was 95±2.5. All surviving larvae (100%) transformed to juveniles, the duration of transformation being 8 days. The early juveniles (0–60 days old) were fed with a mixture of four selected phytoplankton species (Chlorella sp., Kirchneriella incurvata, Navicula sp. and Coccomyxa sp.). The survival rate of juveniles was 8±0.2%. The average length of these juveniles increased from 0.13±0.01 mm to 1.41±0.16 mm and the average height from 0.16±0.01 mm to 0.98±0.09 mm. Subsequently, 60–120-day juveniles were fed with one of the same four phytoplankton species or a combination of the four. Feeding the juveniles with K. incurvata resulted in the highest survival rate (65±8.32%), with an average length of 3.46±0.04 mm and an average height of 1.94±0.04 mm. Finally, the 120–360-day juveniles were cultured in an earthen pond. There were progressive changes in average weight (0.0037±0.002 g to 11.24±5.02 g), length (3.48±0.39 mm to 54.08±6.21 mm), height (1.97±0.24 mm to 25.09±2.48 mm) and width (0.98±0.06 mm to 12.28±3.21 mm) from 120 to 360 days. The average growth rates per day of these parameters were 0.0497±0.01 g, 0.2414±0.15 mm, 0.0975±0.08 mm and 0.0493±0.03 mm, respectively. H. (L.) myersiana juveniles developed the complete structural composition of the adult by 160 days, and at 360 days, gametogenesis was complete.     

Association of leptin genotypes with beef cattle characteristics

A single nucleotide polymorphism (C/T) in bovine leptin, resulting in an arginine to cysteine amino acid substitution (p.Arg25Cys), has previously been shown to have an impact on carcass characteristics. Given the significant energetic relationship between fat and animal efficiency, further evaluation of this SNP across larger animal populations is warranted. Of the total number of 136 286 genotyped cattle in this study, 92 112 and 53 189 were analysed for backfat and body weight measurements, respectively. Results showed a significant positive relationship (P < 0.0001) between the T allele frequency and animal backfat, with TT, CT and CC animals having estimates of 6.79 ± 0.02, 6.49 ± 0.01 and 6.28 ± 0.01 mm, respectively. Calculations using rate of backfat accretion showed that animals with CC genotypes would require more days to reach 12 mm of backfat (45 days) than animals with CT (42 days) and TT (38 days) genotypes. Animal weight was also shown to be positively associated (P < 0.0001) with genotype, as animals of the TT, CT and CC genotypes weighed 484.2 ± 0.7, 488.0 ± 0.5 and 487.3 ± 0.6 kg, respectively, further underscoring the effects of this SNP on key market cattle characteristics.     

Life table parameters of the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae) on different tomato cultivars

The tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato plants originating from South America. In this study, the effect of three tomato cultivars on the life table parameters of T. absoluta was investigated. Data were analysed based on age‐stage, two‐sex life table theory. The net reproduction rate (R₀) of T. absoluta on Falkato, Isabella and Grandella cultivars was determined as 15.73 ± 3.35, 17.66 ± 3.33 and 10.03 ± 4.10 eggs, respectively. The intrinsic rate of increase (r) value on those cultivars was 0.09 ± 0.007, 0.095 ± 0.006 and 0.074 ± 0.017 day^?1, respectively. Finite population rates of increase (λ) were 1.095 ± 0.008, 1.099 ± 0.007 and 1.076 ± 0.018 day^?1, and mean generation times (T) on the three cultivars were 30.09 ± 0.29, 30.22 ± 0.27 and 31.12 ± 0.65 days, respectively. The egg incubation period, pre‐adult duration and fecundity on these tomato cultivars was also calculated. The results showed no significant differences between r, R₀, and T on the three tested tomato cultivars. These findings can be useful for developing an integrated pest management strategy against this noxious pest.     

Effects of cyanobacteria,fish kairomones,and the presence of ostracods on the demography of Simocephalus vetulus (Cladocera)

Simocephalus vetulus is a large (2.0–4.0 mm at maturity) cladoceran often found in the littoral region of lakes and ponds, and capable of moderate growth rates even on poor‐quality cyanobacterial diets. It frequently co‐occurs with fishes and similar sized ostracods such as Heterocypris incongruens, but little is known of its response to fish kairomones or its interactions with potential competitors. We studied the demographic responses of S. vetulus fed the green alga Scenedesmus acutus, Microcystis cf. aeruginosa strain A, Microcystis cf. aeruginosa strain B, or Limnothrix sp. Experiments were conducted separately and together in the presence of Heterocypris incongruens and cichlid fish (Oreochromis) kairomones. A diet of Limnothrix sp. resulted in the lowest population growth rate (0.21±0.023 d^?1), while on diets of S. acutus or Microcystis, population growth was higher (0.30±0.009 d^?1). The presence of ostracods resulted in significantly higher growth rates of S. vetulus fed Limnothrix (0.33±0.01 d^?1), but not Microcystis or S. acutus. Regardless of the diet, the presence of fish kairomones resulted in significantly higher growth rates as compared with controls, particularly when ostracods were also present. Coexistence with ostracods may be beneficial to S. vetulus, particularly when food quality is poor.     

Flexible larval development and the timing of destructive feeding by a solitary endoparasitoid: an optimal foraging problem in evolutionary perspective

1. In studying the evolution of life-history strategies in parasitoids, considerable attention has been paid to the relationship between host quality and parasitoid fitness. Various workers have reported that host quality influences parasitoid size, development time, and survival. Because body size is frequently correlated with fecundity, longevity, and host-finding ability in parasitoids, this parameter is usually considered to be the main target of selection. 2. In koinobiont parasitoids that consume the entire host before pupation, adult parasitoid size and development time are often strongly correlated with host size at the time when it is developmentally arrested through destructive feeding by the parasitoid larva. 3. Here, a mathematical model is proposed to describe the larval feeding behaviour of the solitary koinobiont endoparasitoid Venturia canescens in four larval stadia of its host Plodia interpunctella. In particular, the model describes how adult size, represented by an exponential growth rate, and development time are traded off when the parasitoid develops in nutritionally suboptimal second stadium hosts. 4. Using a graphical model, the different conditions faced by V. canescens during development in various host species of greatly differing mass are illustrated. 5. It is argued that the relative importance of size and development time on parasitoid fitness is determined by ecological and biological characteristics of both host and parasitoid, and it is suggested that there may be correlations between life-history traits and host-utilisation strategies among koinobionts.     

Bio‐priming seeds with cyanobacteria: effects on native plant growth and soil properties

Cyanobacteria are photosynthetic bacteria that form a fundamental part of soil biocrusts, enhance soil function and structure, and can promote plant growth. We assessed the potential of cyanobacteria as a seed bio‐primer for mine‐site restoration in an arid region in Western Australia, examining its effects on native plant growth and the characteristics of mine soil substrates used in dryland restoration. Cyanobacteria strains indigenous to the study region (Leptolyngbya sp., Microcoleus sp., Nostoc sp., and Scytonema sp.) were used to create an inoculant. Seeds of seven native plant species were bio‐primed with the inoculant, and their germination and growth assessed in a laboratory experiment. Seedling growth after bio‐priming was assessed in a glasshouse experiment for a subset of three species, in two different substrates (topsoil and mine waste). Soil properties related to soil function, e.g. total organic carbon, total nitrogen, and microbial activity, were also measured. Minor effects on germination were recorded with only significantly higher germination rates reported in E. gamophylla. Soil parameters were generally higher in topsoil than in mine waste, regardless of bio‐priming treatment. However, bio‐priming resulted in seedlings of four species producing longer radicles and/or shoots. For example, seedling root lengths of bio‐primed G. wickhamii were 57% larger than the control treatment (30.1 ± 4.3 and 13.0 ± 1.6 mm, respectively); and shoots of T. wiseana were 54% longer in the bio‐primed treatment (18.6 ± 1.6 mm) compared to the control (8.53 ± 1.4 mm). Overall, our results highlight that bio‐priming with cyanobacteria may improve plant growth for some species commonly used in dryland restoration.     

Parasitism and oviposition of Melittobia acasta on Bombus terrestris: Impact of larval overwintering and host status on pupation and adult emergence

Melittobia acasta (Walker) are microhymenopteran ectoparasitoids of the pupae and prepupae of the commercially‐used pollinator bumblebee species Bombus terrestris L. The female parasitoids puncture the host cuticle with their sting and feed oozing hemolymph. This study shows that M. acasta parasitize 100% pupae and 84% prepupae of B. terrestris but are ineffective on the larvae of the bees. The female parasitoids lay a significantly higher number of eggs on pupae (67.7 ± 16.2 female^?1) compared to prepupae (20.5 ± 14.5 female^?1). The parasitoids differ in their choice for oviposition sites and fecundity on different locations of B. terrestris pupae, and they show most preference for oviposition (32%) as well as fecundity (34.9 ± 15.1 female^?1) on the petiole of the host. Larvae of the parasitoids overwinter at low temperatures but larval overwintering duration and post‐diapause rearing on original or new hosts do not affect their pupation and adult emergence. Larvae have a higher percentage of pupation (88.0–94.4%) and adult emergence (84.4–92.9%) both on the original and the new host, thus indicate that the parasitoids are highly capable of reproduction in B. terrestris colonies.     

Intraspecific size variation in polyphagous parasitoids (Hym.: Parasitica), of leaf miners and its relation to host size

Wing and body lengths of polyphagous parasitoids of leafminers are analyzed in order to understand the relationship between host and parasitoid sizes. A distinct positive relationship was observed: within each parasitoid species, smaller individuals were reared from smaller hosts. There was no difference between idio-and koinobionts in sexual dimorphism, with females being significantly larger than males in both groups.     

Effect of Body Size on Toxicity of Zinc in Neonates of Four Differently Sized <Emphasis Type="Italic">Daphnia</Emphasis> Species

The sensitivity of neonates of four Daphnia species to zinc was tested in relation to their mean body size. These mean sizes of these four Daphnia spp were: D. magna, 0.813 ± 0.055 mm, D.␣pulicaria, 0.745 ± 0.063 mm, D. pulex, 0.645 ± 0.044 mm and D. galeata, 0.611 ± 0.058 mm. A positive relationship between EC₅₀ (24, 48) values and neonates size was found. The smaller the size of the daphnid the higher was the sensitivity to heavy metal toxicity. For all tested species did the EC₅₀ values decrease with time; the decrease was most marked for D. magna and the least for D. galeata. The EC₅₀ values of D. magna were higher than would be expected on basis of its body size.     

Laboratory studies ofTetrastichus sokolowskii

Under laboratory conditions,Tetrastichus sokolowskii Kurdj. attacksPlutella xylostella larvae of all ages. Development time took from 13 to 19 days. The number of adult parasitoids that emerged per pupa was 8.6±0.2, of which 17.3%±1.2% were ✗. Males were smaller (1.11±0.04 mm) than ♀ ♀ (1.38±0.04 mm). About 62.7±16.9 offspring could be produced per ♀ ♀ and 48% of the eggs were laid on the 1 st day. Both sexes lived longer when fed on sugar or honey solution. When fed on honey, the longevity of ✗ ✗ and ♀ ♀ were 4.8±0.7 and 11.1±1.1 respectively. Despite multiple oviposition attacks, there was no significant difference in the number of offspring produced.      

Situation deLymantria dispar [Lep.: Lymantriidae] et de son complexe parasitaire en Iran,en 1976

Résumé Lymantria dispar (L.) est réparti en Iran dans la région la plus septentrionale du pays, le long de la mer Caspienne. Son aire recouvre le versant nord du massif de l'Elbourz, du nord de Tabriz à l'ouest jusqu'à Bojnurd à l'est. Ses plantes-h?tes sont très variées et comprennent les genres suivant:Alnus, Populus. Gleditschia. Quercus, Carpinus. Prunus. L'inventaire des ennemis naturels deL. dispar, parasites, prédateurs et maladies a été établi. Ces ennemis sont représentés pour la plupart par des espèces connues en Europe. Mais en Iran ils suffisent à maintenir les populations à un niveau très bas. Aucune gradation catastrophique n'a jamais été enregistrée. En 1976, les ravages ont été négligeables. Le taux global de mortalité par les maladies (virose et surtout nosémose) chez les chenilles et les nymphes échantillonnées a atteint 85% et le taux de parasitisme apparent 7%. Le taux de survie deL. dispar a été de 8% seulement. Les insectes parasites les plus efficaces appartiennent à 2 groupes: lesApanteles, avec essentiellementA. melanoscelus (Ratzeburg) et les tachinairesExorista larvarum (L.),Carcelia separata (Rondani) etCompsilura concinnata (Meigen). Les insectes suivants ont eu un impact faible: II s'agit des parasites larvairesBraconidae, Apanteles lacteicolor Viereck,Apanteles liparidis (Bouché),Meteorus pulchricornis (Wesmael);Ichneumonidae Phobocampe sp.,Casinaria tenuiventris (Gravenhorst),Coccygomimus instigator (F.),Lymantrichneumon disparis Poda, des prédateurs larvairesCarabidae. Calosoma sycophanta (L.) etPentatomidae, Picromerus conformis (Herrich-Sch?ffer) et du parasite oophageEupelmidae, Anastatus disparis Ruschka.

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Summary Lymantria dispar (L.) occurs in Iran in the most northern part of the country, bordering the Caspian sea. It is distributed throughout the northern slopes of the Elborz mountains, from the region north of Tabriz in the west to Bojnurd in the east. The host plants are quite varied and include the following genera:Alnus, Populus, Gleditschia, Quercus, Carpinus andPrunus. An inventory was made of the parasites, predators and pathogens ofL. dispar. In general these natural enemies are represented by species also present in Europe. However, in Iran they are able to maintain the population of the host at a very low level and no serious outbreak has ever been recorded. In 1976 the damage was negligible. The total mortality caused by the pathogens (virus and especiallyNosema) reached 85% and the apparent percentage was 7%. Only 8% of the host survived. The most effective insect parasites belonged to 2 groups:Apanteles, primarilyA. melanoscelus (Ratzeburg) and the tachinids,Exorista larvarum (L.),Carcelia separata (Rondani) andCompsilura concinnata (Meigen). The following insects had a minor efficacy: The were the larval parasitesBraconidae: Apanteles lacteicolor Viereck,Apanteles liparidis (Bouché),Meteorus pulchricornis (Wesmael);Ichneumonidae: Phobocampe sp.,Casinaria tenuiventris (Gravenhorst),Coccygominus instigator (F.),Lymantrichneumon disparis Poda; the larval predatorsCarabidae Calosoma sycophanta (L.) andPentatomidae Asopinae Picromerus conformis (Herrich-Sch?ffer) and the oophagous parasiteEupelmidae Anastatus disparis Ruschka.