Abundant Parasitoid Species Research Articles

Damage and Entomophagy in Natural Infestations of Spodoptera frugiperda (Lepidoptera: Noctuidae) in Maize Landraces in Oaxaca, Mexico1

Abstract The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), seriously damages maize (Zea mays L.) crops in tropical, subtropical, and temperate zones of Mexico and around the world. This study was conducted to evaluate the damage caused by S. frugiperda to six native maize populations and the natural parasites of S. frugiperda in three localities from Oaxaca, Mexico. Two native maize populations each of the Zapalote Chico, Bolita, and Conico-Chalqueño races were used. Plantings were done at Coatecas Altas, Santa Lucia Miahuatlan, and Villa de Zaachila under a randomized complete block design with four replications. The agroecological conditions of cultivation influenced the damage caused by S. frugiperda and influenced its natural parasitism. The ordered weighted mean damage in the localities was Villa de Zaachila (1.40–4.92) > Coatecas Altas (1.33–4.06) > Santa Lucia Miahuatlan (0.53–1.00). The order of parasitism rates in the localities was Villa de Zaachila (56.16%) ≈ Santa Lucia Miahuatlan (37.59%) > Coatecas Altas (14.27%). Zapalote Chico populations were less damaged by S. frugiperda larvae and flowered earlier than did the Conico-Chalqueño and Bolita populations. Thirteen parasitoid species and nematodes were recorded attacking S. frugiperda. Chelonus insularis Cresson was the most abundant parasitoid species across the locations. Members of 17 families of predators and 12 families of parasitoids also were identified as potential natural enemies of S. frugiperda. The population dynamics of this armyworm were determined by the environmental conditions of the location, maize population, transition from the vegetative to the reproductive stage, and presence of natural enemies, whereas natural parasitism was influenced only by location.

Potential Parasitoids for Biocontrol of the Ber Fruit Fly, Carpomya vesuviana Costa (Diptera: Tephritidae).

The ber fruit fly (BFF), Carpomya vesuviana Costa, 1854 (Diptera: Tephritidae), is an important key pest of the jujube, Ziziphus jujuba Miller. The main control measures against this pest are to use chemical control, but the first survey for its natural enemies was performed in Iran. Here, we report eight species of parasitic wasps of the BFF from five different families. The family Eurytomidae with three species, the families Pteromalidae and Mutillidae with two species each, and the families Braconidae and Diapriidae with one species each are associated with different immature stages of the BFF, of which Eurytoma pineticola Zerova (Eurytomidae) and Cyrtoptyx lichtensteini (Masi) (Pteromalidae) were the most abundant parasitoid species. Fopius carpomyiae (Silvestri,) was not reared on BFF on the jujube during this survey, but it was reported on Ziziphus spina-christi (L.) with a high parasitism rate. Therefore, it seems to be the most important parasitoid of BFF in Iran. The parasitoid community of BFF in Khorasan, Eastern Iran, is reviewed, and an identification key to these species is proposed.

Changes in the Parasitism Rate and Parasitoid Community Structure of the Horse Chestnut Leafminer, Cameraria ohridella (Lepidoptera: Gracillariidae), in the Czech Republic

The horse chestnut leafminer, Cameraria ohridella, Deschka and Dimić, is a moth that has invaded most of Europe since it was first recorded in Macedonia near Lake Ohrid in 1985. It attacks horse chestnut trees and causes aesthetic and vitality problems. The parasitism rate, other mortality rates, and parasitoid structure were studied during a five-year survey at six sites in the Czech Republic. The results showed that the total parasitism rates varied from 1.9% to 20.5%, with an average of 7.2%, similar to other those published studies. The parasitism rate was significantly related to year, the developmental stage of C. ohridella, latitude, and greenery maintenance but not to C. ohridella population density, altitude, or area size. In contrast, the total other mortality rates varied from 13.7% to 59.5%, with an average of 31%, but overall temporal changes in the values indicated a declining trend. The parasitoid complex was predominantly polyphagous parasitoids of the family Eulophidae, similar to that found previously in south-eastern Europe. The results further revealed that the most abundant parasitoid species, Minotetrastichus frontalis (Nees), was gradually replaced by Pediobius saulius (Walker). The increasing abundance of P. saulius is thus an interesting adaptation of an autochthonous parasitoid to a new host.

Seasonal Variations of Spodoptera frugiperda Host Plant Diversity and Parasitoid Complex in Southern and Central Benin.

Simple SummaryThe detection of fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) in 2016 attacking maize fields in central and west Africa indicated the need to increase the knowledge on the pest host plants and natural enemies adapting to it. A field survey was conducted for two years (from June 2018 to January 2020) to determine host plant and parasitoid records variations across seasons (maize growing and off-seasons) in selected sites in southern and central Benin. A total of eleven new host plant species were reported for the first time, including grasses. The survey revealed seven parasitoid species belonging to four families, namely Platygastridae, Braconidae, Ichneumonidae and Tachinidae, associated with FAW on maize and alternative host plants. The most abundant parasitoid species found was the egg parasitoid Telenomus remus (Nixon) (Hymenoptera: Platygastridae). The study provides crucial information for understanding the bioecology of the pest and for its long-term management using natural enemies.Fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) was recorded for the first time in 2016 attacking maize fields in central and west Africa. Soon after, several other regions and countries have reported the pest in almost the entire sub-Saharan Africa. In the present study, we assumed that (i) a variety of alternative plant species host FAW, especially during maize off-season, (ii) a wide range of local parasitoids have adapted to FAW and (iii) parasitoid species composition and abundance vary across seasons. During a two-year survey (from June 2018 to January 2020), parasitoids and alternative host plants were identified from maize and vegetable production sites, along streams and lowlands, on garbage dumps and old maize fields in southern and partly in the central part of Benin during both maize growing- and off-season. A total of eleven new host plant species were reported for the first time, including Cymbopogon citratus (de Candolle) Stapf (cultivated lemon grass), Bulbostylis coleotricha (A. Richard) Clarke and Pennisetum macrourum von Trinius (wild). The survey revealed seven parasitoid species belonging to four families, namely Platygastridae, Braconidae, Ichneumonidae, and Tachinidae associated with FAW on maize and alternative host plants. The most abundant parasitoid species across seasons was the egg parasitoid Telenomus remus (Nixon) (Hymenoptera: Platygastridae). These findings demonstrate FAW capability to be active during the maize off-season in the selected agro-ecologies and provide baseline information for classical and augmentative biocontrol efforts.

Influence of the site of oviposition on the level of egg parasitism in the corn leafhopper, Dalbulus maidis (Hemiptera: Cicadellidae).

The corn leafhopper Dalbulus maidis (DeLong) (Hemiptera: Cicadellidae), transmits three important plant pathogens that adversely affect corn crop and ranges from the USA to Argentina. The vector has a rich natural enemy complex that generates high levels of parasitism, but its populations are persistent and prevalent. We characterized the oviposition sites of D. maidis on young corn plants in order to verify the hypothesis that the vector has an oviposition strategy for mitigating parasitism. Oviposition locations on plants were assessed in the laboratory and eggs within corn plants were exposed to natural parasitism in a cornfield. Eggs were located mostly laid in the unfolded leaves and were attacked by five parasitoid species. Parasitism was significantly affected by the class of leaf and the position of the egg in the leaf. Anagrus virlai Triapitsyn was the most abundant parasitoid species, which emerged significantly higher in the basal blade than other species. Our results suggest that leafhoppers minimize egg parasitism by laying their eggs within concealed locations on the plant.

Population dynamics and parasitoid complex of Archips rosana (L.) (Lepidoptera: Tortricidae) in Western Turkey

The rose tortrix moth, Archips rosana (L.) (Lepidoptera: Tortricidae), is a pest that causes serious crop losses in apple orchards throughout the world. In this study, the population dynamics of A. rosana and its associated parasitoids were investigated in two provinces of Western Turkey (Denizli and Usak) in 2018 and 2019. A total of 318 egg masses, 300 larvae, and 129 pupae were collected from the survey areas. Although no parasitoids were detected in egg masses, ten parasitoid species belonging to Braconidae, Chalcididae, and Ichneumonidae (Hymenoptera), and Tachinidae (Diptera), were reared from the samples of larvae and pupae. Phytodietus astutus (Gravenhorst) (Ichneumonidae) was the most abundant parasitoid species, with a relative abundance of 35.1%, followed by Itoplectus maculator (Fabricius) (Ichneumonidae) represented by 27% of the recovered parasitoids. Moreover, P. astutus and Scambus inanis (Schrank) (Ichneumonidae) reared from the samples are the first records from Turkey, while Cotesia glomerata (L.) (Braconidae), Exochus sp.(Ichneumonidae), and Nemorilla maculosa (Meigen) (Tachinidae) are the first records from A. rosana. Using pheromone traps in the apple orchards, the first adult of A. rosana was caught on May 24 in Civril (Denizli) and on May 30 in Sivasli (Usak) in 2019

EKSPLORASI DAN IDENTIFIKASI PARASITOID HAMA Plutella xylostella PADA TANAMAN KUBIS Brassica oleracea

This study aims at exploring and identifying parasitoid Plutella xylostella pest on cabbage plants Brassica oleracea in Nduaria Village and finding out the most dominant parasitoid associated with Plutella xylostella pest. Observation variables used included identification of parasitoid species being parasitic in each stage of Plutella xylostella pest life found in the field, parasitoid species abundance and domination of parasitoid. The result of exploration in three sub-villages of NduariaVillage indicated that there were three species of the parasitoid, namely eggof parasitoid Trichogrammatoidae cojuangcoi, the larva of parasitoid Diadegma semiclausum and Cotesia Plutellae. The dominant parasitoid is Diadegma semiclausumwith the value of 0,11. The most abundance in parasitoid larva Diadegma semiclausum is 5,7%. Damage intensity caused by Plutella xylostella was categorized as medium damage intensity of>25-?50%, and this kept rising along with the age of larva and population as well as supporting environment condition due to Plutella xylostella resistance to the pesticide.

Discovery of Parasitoids of Anoplophora glabripennis (Coleoptera: Cerambycidae) and Their Seasonal Abundance in China Using Sentinel Host Eggs and Larvae.

Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), is a high-risk invasive forest pest worldwide. We surveyed Asian longhorned beetle parasitoid guilds and their seasonal abundance using field-deployed sentinel host logs infested with Asian longhorned beetle eggs or newly hatched (early-instar) larvae in three different sites of China (Beijing City, Shanghai City, and Jilin Province) from 2015 to 2018. Our survey detected 12 species of hymenopteran parasitoids (four Pteromalidae, three Braconidae, two Eupelmidae, one Eurytomidae, one Ichneumonidae, and one Bethylidae) attacking sentinel Asian longhorned beetle larvae or eggs deployed in these sites. Total parasitism by all the parasitoid species varied with different sites and across different years of the survey (averaging 7-16% in Beijing, 4-11% in Shanghai, and 0-0.2% in Jilin Province). In addition, the seasonal pattern of parasitism also differed among different sites, with parasitism peaking in July in the northern site (Beijing, 19%) and June in the southern site (Shanghai, 16%). Among all the parasitoid species recovered, Oxysychus sp. (Hymenoptera: Pteromalidae) was the most abundant parasitoid species in both Beijing and Shanghai (with 42-66% relative abundance and an average of 6% Asian longhorned beetle parasitism). The second most abundant species was Bracon planitibiae Yang, Cao et Gould (Hymenoptera: Braconidae), which accounted for 35% of the species collected and caused an average of 5% Asian longhorned beetle parasitism. Relevance of our findings to Asian longhorned beetle biocontrol is discussed.

Biodiversity and population fluctuations of parasitoids of the white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti) (Hemiptera: Diaspididae), in kiwifruit orchards in Northern Iran

Summary The white peach scale, Pseudaulacaspis pentagona Targioni-Tozzetti (Hemiptera: Diaspididae), is one of the most important and destructive polyphagous pests of the Rosaceae family trees. Population fluctuations and biodiversity of the hymenopteran parasitoid species associated with the pest were studied in six kiwi orchards in Iran, during one-year period. Parasitoid species abundance, species diversity indices and evenness indices were calculated. Most of the parasitoid species were dominant or eudominant. Based on the alpha diversity indices, the Najarkola region had high diversity and the Kharatkola region had low diversity. The Paeendasteh region (based on Simpson’s Diversity on Camargo evenness indices) and the Samnakola region (based on the modified Nee, and on Smith and Wilson evenness indices) were less uniform. Among the recorded parasitoids, Encarsia berlesei Howard (Hymenoptera: Aphelinidae), followed by Aphytis proclia Walker (Hymenoptera: Aphelinidae), had the highest population in all orchards.

Natural Enemy Communities and Biological Control of Parthenolecanium spp. (Hemiptera: Coccidae) in the Southeastern United States.

We documented the species composition, seasonal ecology, and impacts of parasitoids and predators of Parthenolecanium corni (Bouché) and P. quercifex (Fitch) (Hemiptera: Coccidae) in the urban landscapes of Georgia, North Carolina, South Carolina, and Virginia, United States. Twenty-one parasitoid morphospecies and 12 predator species were collected through rearing, beat sheet, and sticky card trapping. Coccophagus lycimnia (Walker) (Hymenoptera: Aphelinidae) was the most abundant parasitoid species in South Carolina, North Carolina, and Virginia, whereas Metaphycus sp. 2 (Hymenoptera: Encyrtidae) was the most abundant species in Georgia. Parasitism rates ranged from 59 to 92% in the nymphal population and 27 to 84% in the adult population in South Carolina. Blastothrix sp. 1 (Hymenoptera: Encyrtidae), C. lycimnia, Encyrtus sp. 1 (Hymenoptera: Encyrtidae), Eunotus sp., and Pachyneuron sp. (both Hymenoptera: Pteromalidae) emerged from adult scale insects and significantly reduced the fecundity of parasitized scale insects. Coccophagus lycimnia was the only parasitoid species emerged from nymphs. Hyperaspis signata (Olivier) species group, Chilocorus stigma Say (both Coleoptera: Coccinellidae), and Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae) were the most abundant predators in South Carolina. The majority of natural enemies (87% of parasitoids and 82% of predators) were active from late March to late August and from late April to late October, respectively.

Seasonal Abundance of the Adventive Chinese Tallowtree HerbivoreCaloptilia triadicae(Lepidoptera: Gracillariidae) and Its Parasitoids

Chinese tallowtree, Triadica sebifera (L.) Small (Malpighiales: Euphorbiaceae), is an invasive weed from southern China that is invasive in the Gulf states of the southeastern USA. One significant factor that contributes to the success of this weed has been the lack of herbivore species attacking it in the invaded range. However, the leafminer species Caloptilia triadicae Davis (Lepidoptera: Gracillariidae) was discovered feeding on Chinese tallowtree in Florida in 2008 and has now been found throughout much of the plant's invaded range. We monitored the seasonal abundance of C. triadicae populations and their associated parasitoids over 2 yr in Florida. Populations of C. triadicae peaked in Jun and Jul in 2013 and 2014. Parasitism averaged about 3.3% of larvae and pupae, with a peak of 12%. The most abundant parasitoid species was Goniozus sp. (Hymenoptera: Bethylidae) (76% of all parasitoid individuals reared) and, second, Brasema sp. (Hymenoptera: Eupelmidae) (18% of parasitoids). Due to specific niche requirements and the apparent exploitation of leaf mines by these parasitoid species, it is doubtful they will attack species being considered for biological control of Chinese tallowtree.

緑肥作物ハゼリソウにおけるハモグリバエ類（ハエ目：ハモグリバエ科）の土着寄生蜂相とネギハモグリバエ防除のためのバンカープランツおよびインセクタリープランツとしての利用の可能性

Phacelia tanacetifolia Bentham is known worldwide as a kind of insectary plant and is used in Japan as a green manure crop before Welsh onion planting. To explore the possibility of using P. tanacetifolia as a banker plant or an insectary plant for parasitoids of Liriomyza chinensis Kato, we investigated the seasonal abundance of agromyzid leafminers and their hymenopterous parasitoids on infested leaves and blooming flowers of P. tanacetifolia collected in Chiba Pref., Japan, in 2009, 2010, and 2012. We also investigated longevity increase in Diglyphus isaea（Walker）adults with a blooming P. tanacetifolia plant in the laboratory. Almost all agromyzid leafminers reared from leaves were Chromatomyia horticola（Goureau）. Twenty-one parasitoid species including seven species reported from L. chinensis mines by different authors in Japan were reared from leaves, and nine species including eight species reared from leaves were caught on flowers. The most abundant parasitoid species was D. isaea. In this study, Diglyphus crassinervis Erdös was reared from C. horticola for the first time in Japan. The longevity of D. isaea adults provided with a blooming plant and water was about 18 days at 24°C with a 16L : 8D photoperiod. The log-rank test, used to compare survival curves from the 2 treatments; with and without blooming P. tanacetifolia plant, showed a statistically significant difference between treatments. These results suggest that P. tanacetifolia has potential as a banker plant or insectary plant for parasitoids to control L. chinensis in Welsh onion fields.

Distributional patterns of fall armyworm parasitoids in a corn field and a pasture field in Florida

An assessment of parasitoids and their selective patterns among Spodoptera frugiperda corn and rice host strains was performed from August 2008 to August 2010 in a corn crop and a grass pasture in northern Florida under different seasonal conditions (spring and fall). Sentinel larvae from our laboratory were placed in both habitats. Results obtained in the corn crop differed from those in the pasture due to poor recovery rate of larvae in the pasture habitat. In corn fields, we found that the parasitoid community was composed of eight species of Hymenoptera and one Diptera species, which represented four families and two guilds. The more abundant parasitoid species in the corn field included Aleiodes laphygmae, Meteorus autographae, Cotesia sp., Euplectrus platyhypenae and Ophion flavidus while the Diptera species constituted the most abundant parasitoid in pastures. Among the parasitoid species collected in pastures were three Diptera species and four hymenoptera species.Parasitoid species did not discriminate among fall armyworm host strains, however they varied among the different habitats in the corn field. The ectoparasitoid Euplectrus platyhypenae and an unknown ichneumonid species were found primarily at the edges of the crop (in areas adjacent to the woods); while the endoparasitoids Cotesia sp. and Meteorus sp. were recovered more often in the main corn crop. Meteorus and Ophion were more abundant in the spring while the unknown ichneumonid was more abundant in the fall. Predator species differ among corn and pasture, which might contribute to the dynamics of parasitoid species in these fields.

Diversity and Abundance of House Fly Pupal Parasitoids in Israel, with First Records of Two Spalangia Species.

Filth flies (Diptera: Muscidae), particularly the house fly, Musca domestica L., are global pests of livestock production. In this study, we characterized the fauna of house fly pupal parasitoids in Israel and identified factors affecting their diversity and abundance. The study, which included one round of sampling during the fall of 2013 and another round of sampling in the spring of 2014, encompassed 26 locations of common fly-breeding habitats: dairy, egg-laying, and goat farms throughout Israel. Nine parasitoid species were found: Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia drosophilae Ashmead, Spalangia gemina Boucek, Spalangia nigroaenea Curtis, Pachycrepoideus vindemmiae Rondani, Muscidifurax raptor Girault and Sanders, Muscidifurax zaraptor Kogan & Legner (all Hymenoptera: Pteromalidae), and Dirhinus giffardii Silvestri (Hymenoptera: Chalcididae). This is the first record of S. gemina from the Palearctic, as well as the first record of S. drosophilae from the Middle East. The composition and relative abundance of parasitoid species varied markedly among localities, climatic regions (Mediterranean vs. desert), habitat types (dairy vs. egg-laying vs. goat farm), and seasons. Overall, parasitoid richness in egg-laying farms was two- and sevenfold higher than in dairy and goat farms, respectively, and three times higher in Mediterranean than desert climate. The significance and implications of our results for inundative biological control programs of filth flies are discussed.

Ecological and morphological characteristics of parasitoids in Phauda flammans (Lepidoptera, Zygaenidae).

Phauda flammans Walker (Lepidoptera, Zygaenidae) is one of the notorious defoliators on Ficus spp. trees. In order to avoid environmental pollution, potential biological control agents for P. flammans need to be investigated instead of chemical control. Four species of insect parasitoids were identified from P. flammans, including three hymenopteran species (i.e., Gotra octocinctus, Apanteles sp. and Eurytoma verticillata) and one dipteran species (i.e., Exorista yunnanica). Parasitoid ratios of G. octocinctus, Apanteles sp., Eu. verticillata and Ex. yunnanica were 7.2%, 4.2%, 1.6% and 0.9%. The four species were all larval endoparasitoids of P. flammans larvae. Time of cocoon (pupa) to adult, life span, major axis of cocoon and body length of females were all longer compared to males for G. octocinctus, Apanteles sp. and Ex. yunnanica. Based on the parasitoid ratios, the most abundant parasitoid species was G. octocinctus.

Distinct parasitoid communities associated with host races of the leaf-mining moth Acrocercops transecta on distantly related host plants (Juglandaceae and Ericaceae)

Differences in host-plant species may affect the structure of parasitoid communities of phytophagous insects. Phytophagous insect species often consist of host races, and comparisons between host races enable us to infer the effects of host-plant differences on parasitoid communities. Here, we compare the parasitoid fauna of two host races of the leaf-mining moth Acrocercops transecta, which are associated with either Juglandaceae or Lyonia ovalifolia (Ericaceae). Field collection and subsequent laboratory rearing revealed a significantly higher parasitization ratio in the Juglandaceae race than in the Lyonia race. In the Juglandaceae race the majority of parasitoids were Braconidae, whereas in the Lyonia race the majority were Eulophidae. Furthermore, even within the same host race the most abundant parasitoid species differed between populations with different host associations. Hence, the present results strongly indicate that different host-plant taxa affect the structure of parasitoid communities even within a single phytophagous insect species.

Multiple ant species tending lac insect Kerria yunnanensis (Hemiptera: Kerriidae) provide asymmetric protection against parasitoids.

This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the first two factors.

Natural Enemies of the LeafminerLiriomyza trifolii(Diptera: Agromyzidae): Challenges and Perspectives for its Biological Control

Abstract. The leafminer Liriomyza trifolii (Burgess) is native to the United States of America and distributed around the world. In the central part of Mexico and Tamaulipas it is considered an economically important pest attacking peppers and chrysanthemums. In addition, in the state of Sinaloa, this pest has been reported in peppers, tomatoes, cucurbits, and other vegetables. Different authors state that L. trifolii becomes a pest when its enemies are eliminated, especially parasites, and also by its resistance to insecticides. In different regions of the world including Mexico, diverse and abundant parasitoid species of the leafminer are considered important options for augmentative and conservation and enhancement biological control. The combined use of low- or reduced-impact insecticides on non-target species and cultural practices might favor populations of parasites. The purpose of this report was to promote the use of developed technologies related to biological control of the leafminer to encoura...

Introduced and native parasitoids of Phyllocnistis citrella Stainton in Greece: short term post-release evaluation

The Citrus Leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is considered an important pest of citrus, damaging mainly nursery plants. In Greece it was first recorded on the island of Rhodes in 1995 and rapidly spread to all citrus growing areas of the country. Due to its wide expansion and damage, efforts were initiated to control this pest with biological control agents. For this purpose, a number of exotic parasitoids, such as Citrostichus phyllocnistoides (Narayanan), Quadrastichus sp. Girault and Semielacher petiolata (Girault) (Hymenoptera: Eulophidae), were introduced, reared in insectaries and released in several regions of Greece. The species composition and the seasonal abundance of the native parasitoids, as well as the recovery of the released parasitoids, were investigated in weekly samplings during 1998 and 1999 in a citrus orchard in Argolis district. Results showed that among the released parasitoids, only C. phyllocnistoides was recovered. Among the native parasitoids, Neochrysocharis formosa (Westwood), Pnigalio pectinicornis (L.) and Cirrospilus sp. Westwood (Hymenoptera: Eulophidae) were identified. The most abundant parasitoid species was the exotic C. phyllocnistoides. The highest percent of parasitism in 1999 increased approximately by 46% compared with that of the previous year. The percent of parasitism increased to its maximum level during November, at the end of the sampling period in both years, when the population density of C. phyllocnistoides was high.

Inconsistent genetic structure among members of a multitrophic system: did bruchid parasitoids (Horismenusspp.) escape the effects of bean domestication?

Anthropogenic range expansion and cultural practices have modified the distribution, abundance and genetic diversity of domesticated organisms, thereby altering multitrophic assemblages through space and time. The putative Mesoamerican domestication centre of the common bean, Phaseolus vulgaris L., in Mexico allows investigating the effects of plant domestication on the genetic structure of members of a multitrophic system. The aim of this study was to compare the evolutionary history of Horismenus parasitoids (Hymenoptera: Eulophidae) to those of their bruchid beetle hosts (Coleoptera: Bruchidae) and their domesticated host plant (P. vulgaris), in the context of traditional agriculture in Mexico. We analyzed the population genetic structure of four Horismenus species in Mexico using mitochondrial COI haplotype data. The two most abundant parasitoid species were Horismenus depressus and Horismenus missouriensis. Horismenus missouriensis were infected by Wolbachia endosymbionts and had little to no population differentiation (F(ST) = 0.06). We suspect the mitochondrial history of H. missouriensis to be blurred by Wolbachia, because differentiation among infected vs. non-infected individuals exists (F(ST) = 0.11). Populations of H. depressus were found to be highly differentiated (F(ST) = 0.34), but the genetic structuring could not be explained by tested spatial components. We then compared the genetic structure observed in this parasitoid species to previously published studies on bruchid beetles and their host plants. Despite extensive human-mediated migration and likely population homogenization of its two Acanthoscelides bruchid beetle hosts, H. depressus populations are structured like its host plant, by a recent dispersal from a diverse ancestral gene pool. Distinct evolutionary dynamics may explain inconsistent patterns among trophic levels. Parasitoids likely migrate from wild bean populations and are poorly adapted to bean storage conditions similar to their bruchid beetle hosts. Integrating several trophic levels to the study of evolutionary history has proven to be fruitful in detecting different ecological responses to human-mediated disturbances and host parasite interactions.