Original Release Site Research Articles

Update on the establishment of Thripoctenus javae in New Zealand and new locality records in Bay of Plenty kiwifruit orchards

The larval parasitoid, Thripoctenus javae (Hymenoptera: Eulopidae), was introduced into New Zealand in 2001 as a biological control agent for greenhouse thrips, Heliothrips haemorrhoidalis. We have re-evaluated the establishment of T. javae at the release sites from Kerikeri to Gisborne and surveyed kiwifruit orchards in the Bay of Plenty to determine how widespread the parasitoid has become. Release sites were surveyed in autumn 2017 for greenhouse thrips. Foliage samples were collected from numerous host plants, where greenhouse thrips were found, and the number of T. javae pupae on each leaf were recorded. In 2018, a second survey for T. javae was conducted in Bay of Plenty; samples of cryptomeria (Cryptomeria japonica) shelterbelt foliage were collected from 65 kiwifruit orchards. Foliage samples were washed and pupae of T. javae were counted. Thripoctenus javae were recorded at 80% of the original release sites from Kerikeri to Gisborne. The parasitoid was found at all sites in Whangarei and Bay of Plenty, 50% of sites in Kerikeri, 33% of revisited sites in Gisborne as well as the single site in Auckland. No host populations of greenhouse thrips were found at four release sites (Kerikeri =2 and Gisborne =2). In Bay of Plenty, T. javae were found at 32 kiwifruit orchards (49% of the total surveyed). All of these orchards are new locality records for T. javae. The furthest distance T. javae was found from a release site was 55.4 km. The introduction of T. javae into New Zealand has been successful with the parasitoid recorded at 80% of the original release sites after 17 years. Dispersal is evident in the Bay of Plenty where we have detected T. javae at 32 new locations on kiwifruit orchards.

Captive sentinel hosts efficiently measure the establishment, seasonality and dispersal of a parasitoid biological control agent

Introduced biological control agents are used to suppress populations and reduce the damage caused by many exotic herbivorous insects in New Zealand pasture. Understanding the dispersal behaviour of a recently introduced biocontrol agent in its new environment is important as it helps biocontrol practitioners make decisions on the number and location of future releases. In this study, a monitoring device which contained sentinel hosts was developed to monitor the establishment and dispersal of the Irish strain of Microctonus aethiopoides (Hymenoptera, Braconidae) into areas of the South Island of New Zealand where the clover pest Sitona obsoletus Gmelin (Coleoptera, Curculionidae) had recently become established. Field tests of the monitoring device at five sites in Marlborough confirmed that M. aethiopoides would enter the device through a 900 µm mesh and parasitise the sentinel weevils within. In a further trial conducted over 4 years at four sites in North Canterbury, monitoring devices successfully tracked the dispersal and establishment of M. aethiopoides at sites up to 27 km from the original release site. Monitoring devices containing sentinel hosts may help reduce the cost of classical biological control programmes as they enable rapid sampling of numerous sites and largely eliminate the time consuming practice of dissecting field collected hosts to determine the presence of the parasitoid.

The impacts of biological control on the performance of Lythrum salicaria 20 years post-release

Biological control has the potential to be an effective tool in the control of invasive plants. However, because it involves the introduction of a novel species to an ecosystem, predicting the potential impacts and overall effectiveness can be difficult, especially at the outset. For this reason, long term follow up of programs is essential. Unfortunately, few programs include official follow up, and those that do are often not collecting all the information necessary to assess the benefits and risks. Here we describe a study where we performed plant population surveys to estimate the impacts of a large scale release of two species of chrysomelid beetles, Neogalerucella calmariensis and N. pusilla on the control of the invasive wetland plant, Lythrum salicaria in Ontario, Canada. We surveyed 18 populations that varied in their colonization history, including a set that are among the original sites of the Ontario government’s planned release program initiated in 1992. We discovered that L. salicaria plants at the original release sites exhibited more herbivore damage and fewer primary inflorescences relative to those at naïve (never colonized) or recent (those apparently colonized via migration) sites. We also discovered that, across sites, quadrats with a heavier load of Neogalerucella spp. tended to have lower overall plant species richness, which was likely due to the fact that beetles tend to congregate in areas with high target plant density. Surprisingly, many of the factors associated with a successful release program, such as reduced target plant density, reduced target plant fruit production, and reduced above- and/or belowground plant biomass at release sites were not detected in our study. We discuss the potential reasons for our findings and make recommendations for the application of biocontrol and follow up programs.

Translocation, genetic structure and homing ability confirm geographic barriers disrupt saltwater crocodile movement and dispersal.

Translocated saltwater crocodiles (Crocodylus porosus) in the Northern Territory (NT) of Australia often return to their original capture sites, which complicates management interventions aimed at reducing human-crocodile conflict. We examined the spatial events implicated in this homing ability, using ARGOS satellite tracking devices. Five large male C. porosus (3.03 m to 4.02 m TL) were shifted and released 100–320 km from their capture sites, and 3 additional ones (3.67 m to 4.23 m TL) were released at their site of capture as controls. Translocated crocodiles were more mobile than the controls, and moved at sea in the direction of their original capture site. However, they were unable or unwilling to swim around a geographic structure, Cobourg Peninsula, which prevented homing being achieved in all five cases. Two control crocodiles remained near their capture sites, but one, after the first year, made a 900km journey for six months, before returning to its original capture and release site. Genetic analysis of tissue samples from nests across the NT coast demonstrated significant genetic structure across the coast, and confirmed that Cobourg Peninsula contributes to genetic differentiation among populations along the NT coast. These results provide new insights into C. porosus movements, which have management significance for the maintenance of public safety.

Harmonic radar tracking reveals random dispersal pattern of bumblebee (Bombus terrestris) queens after hibernation

The dispersal of animals from their birth place has profound effects on the immediate survival and longer-term persistence of populations. Molecular studies have estimated that bumblebee colonies can be established many kilometers from their queens’ natal nest site. However, little is known about when and how queens disperse during their lifespan. One possible life stage when dispersal may occur, is directly after emerging from hibernation. Here, harmonic radar tracking of artificially over-wintered Bombus terrestris queens shows that they spend most of their time resting on the ground with intermittent very short flights (duration and distance). We corroborate these behaviors with observations of wild queen bees, which show similar prolonged resting periods between short flights, indicating that the behavior of our radar-monitored bees was not due to the attachment of transponders nor an artifact of the bees being commercially reared. Radar-monitored flights were not continuously directed away from the origin, suggesting that bees were not intentionally trying to disperse from their artificial emergence site. Flights did not loop back to the origin suggesting bees were not trying to remember or get back to the original release site. Most individuals dispersed from the range of the harmonic radar within less than two days and did not return. Flight directions were not different from a uniform distribution and flight lengths followed an exponential distribution, both suggesting random dispersal. A random walk model based on our observed data estimates a positive net dispersal from the origin over many flights, indicating a biased random dispersal, and estimates the net displacement of queens to be within the range of those estimated in genetic studies. We suggest that a distinct post-hibernation life history stage consisting mostly of rest with intermittent short flights and infrequent foraging fulfils the dual purpose of ovary development and dispersal prior to nest searching.

The Distribution and Abundance of the Stem-Galling Fly,Cecidochares connexa(Macquart) (Diptera: Tephritidae), a Biological Control Agent ofChromolaena odorata(L.) (Asteraceae), in Ghana

Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae: Eupatorieae) is one of the worst invasive weeds in West Africa, and a serious biotic threat to food security. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), a biological control agent for C. odorata, was released in the Ivory Coast in 2003 and first detected in Ghana in 2014. The spatiotemporal distribution and abundance of C. connexa in Ghana was determined by country-wide surveys from 2015 to 2016. Galls were found in varying densities across Ghana but gall densities were consistently low east of Lake Volta. A limited survey conducted in the extreme west of Togo in 2016, found the gall fly also in low numbers. There was a significant correlation between C. connexa gall densities and the distance from the release sites in the Ivory Coast. The distribution and abundance of the gall fly in Ghana could be explained by its spread from the original release sites over time and/or the much drier conditions east of Lak...

Spatial and temporal variation of biological control agents associated with Eichhornia crassipes in the Sacramento-San Joaquin River Delta, California

The invasive water hyacinth (Eichhornia crassipes) severely limits the ecosystem services provided by the Sacramento-San Joaquin River Delta in California, USA. As part of the biological control program in the Delta, two weevils, Neochetina bruchi and N. eichhorniae (Coleoptera: Curculionidae) and a moth, Niphograpta albiguttalis (Lepidoptera: Pyralidae), were released in the 1980s. Additionally, a planthopper, Megamelus scutellaris (Hemiptera: Delphacidae) was released in 2011. We conducted monthly surveys for one year at 16 sites throughout 1667km2 of the Delta to determine the resulting establishment, abundance and distribution of these introduced herbivores. Morphological identifications, and partial sequencing of the mitochondrial cytochrome oxidase subunit 1 gene determined that 96.6% of the examined weevils were N. bruchi. N. eichhorniae was only recovered from two sites in the southern Delta tributaries. Densities (larvae and adult weevils per destructively sampled plant) varied spatially and temporally. Peak mean densities (averaged across August–November) decreased with increasing distance from the original release sites. Peak mean densities ranged from 0.31 to 6.31 weevils per plant. Densities averaged across sites were the lowest in June 2015 (0.54 weevils), increasing in August to 5.35 weevils, and peaking in November at 6.22 weevils. The proportion of damaged leaf area from weevil feeding increased concomitantly with weevil densities. Although N. albiguttalis was not recovered, M. scutellaris remained established at its original release site but has not dispersed into the other surveyed regions. We propose hypotheses to explain patterns in species establishment and distribution, with potential mechanisms for improved future biological control.

Establishment, dispersal and impact of the flower-galling mite Aceria lantanae (Acari: Trombidiformes: Eriophyidae) on Lantana camara (Verbenaceae) in South Africa

The flower-galling mite, Aceria lantanae (Cook) (Acari: Trombidiformes: Eriophyidae), was released as a biological control agent of Lantana camara L. (Verbenaceae) in the Limpopo, Mpumalanga, Gauteng and KwaZulu-Natal provinces of South Africa, between 2007 and 2012. Flower galls were subsequently observed at several sites where the mite had not been released, providing evidence of dispersal. This study was therefore conducted to determine the establishment, seasonal performance and dispersal rate of A. lantanae in the aforementioned South African provinces and neighbouring Swaziland. The effect of A. lantanae along with the other previously-established biological control agents on inflorescence and seed production of susceptible L. camara varieties was determined by insecticide exclusion experiments in the field. Aceria lantanae became established at 58.6% of the original release sites located in the four provinces. The mite has also established widely within the geographic range of L. camara in South Africa and Swaziland, with dispersal rates of up to 40.6km per annum. Infestations of inflorescences varied substantially between sites, provinces and seasons and ranged from 2.7% to 97%. Inflorescence and seed production declined significantly by up to 97% and 94%, respectively, on untreated biological control stands compared to the insecticide-treated exclusion stands. Although A. lantanae has become widespread within the geographic range of L. camara in South Africa, different L. camara plants appeared to vary in their susceptibility to A. lantanae, suggesting that genetic differences among plants may have affected the performance of the mite. If this is true, additional mite strains will be required to control resistant varieties.

Dynamics of Reintroduced Populations of Oedipoda caerulescens (Orthoptera, Acrididae) over 21 Years.

Conservation programs increasingly involve the reintroduction of animals which otherwise would not recolonize restored habitats. We assessed the long-term success of a project in which the Blue-winged grasshopper, Oedipoda caerulescens (L., 1758), was reintroduced to a nature reserve in Northwestern Switzerland, an alluvial gravel area where the species went extinct in the 1960s. In summer 1995, we released 110 individuals (50 females and 60 males) and 204 individuals (101 females and 103 males) into two restored gravel patches with sparse vegetation. We used a transect count technique to assess the population size of O. caerulescens in the years 1995–2004 and 2015–2016 and recorded the area occupied by the species. At both release sites, the populations persisted and increased significantly in size. Individuals that followed a newly created corridor established four new subpopulations. Seven years after reintroduction, O. caerulescens had reached a high abundance around the release sites and in the four colonized patches, indicating a successful project. At the same time, the dispersal corridor became increasingly overgrown by dense vegetation. Surveys 20 and 21 yr after introduction showed that the abundance of the Blue-winged grasshopper had strongly declined in the established subpopulations and moderately in the original release sites, owing to natural succession of the habitat and lack of disturbances, which reduced the area suitable for the species by 59%. Our study shows that reintroductions are unlikely to succeed without integration of long-term habitat management (in the present case maintenance of open ground).

Acoustic positioning and movement patterns of red snapper, Lutjanus campechanus, around artificial reefs in the northern Gulf of Mexico

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 553:233-251 (2016) - DOI: https://doi.org/10.3354/meps11778 Acoustic positioning and movement patterns of red snapper Lutjanus campechanus around artificial reefs in the northern Gulf of Mexico Laura Jay Williams-Grove*, Stephen T. Szedlmayer School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, 8300 State Highway 104, Fairhope, Alabama 36532, USA *Corresponding author: laurajaygrove@gmail.com ABSTRACT: Over a 3 yr period fine-scale (m) movements of red snapper Lutjanus campechanus were estimated with the Vemco VR2W Positioning System (VPS) on 3 artificial reefs, and wider scale (km) movements were estimated with surrounding receivers (n = 23). Tagged red snapper (n = 56) were tracked for extended periods (17–1096 d). Residency (23 mo) and site fidelity (82% yr-1) showed that red snapper maintained a close association with the artificial reef structure (34.5 ± 44.0 m). Fine-scale monthly home range (95% kernel density estimates [KDE]) and core areas (50% KDE) were positively correlated with water temperature. In the winter, all red snapper showed less movement, and during the warmer months most (63%, 29 out of 46) fish used a secondary reef site. Over diel periods, fish showed significantly greater movements during day hours on 2 reef sites and during night hours on 1 reef site. The surrounding receiver array validated 88% (15 of 17 fish) of the VPS-determined emigrations. Many (53%, n = 9) fish moved short distances (~1.5 km) to nearby reefs, and some red snappers (n = 3) that emigrated returned to their original release site. Red snapper showed some prey-like behaviors, e.g. close association with reef structure, quick movements over open habitat, and paired emigrations to nearby sites. These behaviors suggested that red snapper are subject to predation by larger apex predators, and as stocks increase, such factors will become increasingly more important for future management. KEY WORDS: Telemetry · Residency · Site fidelity · Emigrations Full text in pdf format PreviousNextCite this article as: Williams-Grove LJ, Szedlmayer ST (2016) Acoustic positioning and movement patterns of red snapper Lutjanus campechanus around artificial reefs in the northern Gulf of Mexico. Mar Ecol Prog Ser 553:233-251. https://doi.org/10.3354/meps11778 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 553. Online publication date: July 14, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

A multiyear year study of three plant communities with purple loosestrife and biological control agents in Virginia

Purple loosestrife (Lythrum salicaria L.) native to Eurasia has become an invasive weed in North America since its introduction in the late eighteenth century. To control L. salicaria; Galerucella calmariensis L., Galerucella pusilla Duftschmidt, and Hylobius transversovittatus Goeze were released at Coeburn (Sites 1 and 2) and Big Island, Virginia in 1992 and 1999, respectively. The biocontrol agents and plant community parameters were studied for 11 and 14years at Big Island and Coeburn, respectively. The Galerucella spp. and H. transversovittatus became established at both sites. After 8years Galerucella spp. at Coeburn dispersed 1768m with a mean of 221m/year from the original release site. H. transversovittatus was found 400m from the original release site at Coeburn after 14years. Both Galerucella spp. were found in similar ratios at Coeburn. At Big Island the biocontrol agents did not spread due to the low L. salicaria density beyond the release site. At Coeburn Site 1 L. salicaria percent cover, May and fall stem density, seed capsules and total inflorescence length per m2 significantly declined by 88%, 98%, 97%, 94%, and 88%, respectively. While L. salicaria declined non-native and invasive species percent cover increased at Coeburn Site 1. Non-invasive species cover also increased but was lower than the invasive species cover. At Coeburn Site 2 L. salicaria was much denser and did not decline after 11years. Invasive species were also lower in density than at Coeburn Site 1, possibly allowing L. salicaria to maintain its competitive advantage over other species at Site 2. No significant reductions occurred in percent cover, stem height, seed capsules or inflorescence length per m2 in any of the L. salicaria metrics at Big Island except the number of stems per m2 which declined. Deer herbivory was high at Big Island and may have reduced Galerucella spp. density and its impact on L. salicaria metrics. Percent cover of native, non-native, and invasive species significantly increased at Big Island with non-native species increasing at a faster rate. The biological control agents had a significant impact on L. salicaria at Coeburn Site 1 but not at Coeburn Site 2 or Big Island. While L. salicaria was reduced by the biocontrol agents at Coeburn Site 1, invasive species became more abundant. Non-native and invasive species increased and the quality of this plant community remained low. Future weed biological control programs should include habit restoration.

Biological Control of Saltcedar (Tamarixspp.) by Saltcedar Leaf Beetles (Diorhabdaspp.): Effects on Small Mammals

Abstract. The spread of introduced saltcedar (Tamarix spp.) throughout many riparian systems across the western United States motivated the introduction of saltcedar leaf beetles (Diorhabda carinulata, D. elongata; Chrysomelidae) as a biological control agent specific to saltcedar. I monitored small mammal populations for up to 12 years as saltcedar defoliation progressed at 3 of the original saltcedar beetle release sites and at an additional site where beetles established through dispersal. There was no evidence of any linear effect of increasing defoliation over time on small mammal species richness. Estimated population sizes of 4 small mammal species, based on mark-release-recapture trapping, showed linear responses to saltcedar defoliation at particular sites, but all of these species were represented by only 3 years of data at those sites. Increases in the abundance of 2 species of desert-adapted heteromyid rodents, Merriam's kangaroo rat (Dipodomys merriami) and Panamint kangaroo rat (D. panaminti...

Current Status of the Biological Control AgentNeomusotima conspurcatalis(Lepidoptera: Crambidae), onLygodium microphyllum(Polypodiales: Lygodiaceae) in Florida

Summary The brown Lygodium defoliating moth, Neomusotima conspurcatalis Warren (Lepidoptera: Crambidae), was released beginning in 2008 to control Old World climbing fern, Lygodium microphyllum (Cav.) R. Br (Polypodiales: Lygodiaceae). The moth readily established in Jonathan Dickinson State Park, but at other sites populations remained at low densities or were locally extirpated. In 2012 and 2013, we recovered N. conspurcatalis populations at all original release sites except Everglades National Park and those treated with herbicide. The original releases of 4,000 or more individuals per site were entirely successful, pointing to a strategy that focuses on numbers at this target level or beyond for future releases in Florida.

Dispersal and Establishment of New Populations of the Biological Control AgentFloracarus perrepae(Acariformes: Eriophyidae) on Old World Climbing Fern,Lygodium microphyllum(Polypodiales: Lygodiaceae)

Summary The mite Floracarus perrepae Knihinicki & Boczek (Acariformes: Eriophyidae), a biological control agent of Lygodium microphyllum (Cav.) R. Br (Polypodiales: Lygodiaceae), Old World climbing fern, was released in south Florida from 2008 to 2010 but did not readily establish in the field. The original release sites were re surveyed in 2013 and the mite has established within Jonathan Dickinson State Park and has dispersed to L. microphyllum patches outside the park at a rate of 3.5 ± 0.6 km/yr. The mite has also dispersed to the Cape Sable region of Everglades National Park.

Post-release dispersal of the introduced lygus bug parasitoid Peristenus relictus in California

Lygus spp. (Heteroptera: Miridae) are serious pests of numerous field and fruit crops in North America. In an effort to reduce crop damage, parasitoids known to attack these species in Europe were introduced into the USA beginning in the 1970s. Permanent populations of the nymphal endoparasitoid Peristenus relictus (Hymenoptera: Braconidae) were established at two locations in California during the 2000s. Both populations are associated with significant reductions in lygus bugs attacking alfalfa, commercially produced strawberries grown organically and in wild vegetation. Beginning in 2009, in an effort to determine the extent to which P. relictus has spread from the Sacramento Valley and Monterey Bay region, populations of lygus bug were sampled at increasing distances from their original release sites. P. relictus has dispersed at least 213 km in the central region of California and 150 km along the coastal mountains. These respective populations have averaged 16.6 km/year and 17.7 km/year since they were released. While not directly examined, the spread of P. relictus south into the central and major growing region of California, the San Joaquin Valley, where previous releases have failed, suggests this population may be evolving greater heat tolerance, relative to the populations originally introduced into California.

Establishment, dispersal, and prevalence of Rhinocyllus conicus (Coleoptera: Curculionidae), a biological control agent of thistles, Carduus species (Asteraceae), in Argentina, with experimental information on its damage

Use of the weevil, Rhinocyllus conicus Froelich, for classical biological control of Carduus species in Argentina has not been controversial, as it has been in Canada and the United States, because there are no native thistle species in the South American release areas. In this study, 30years after its first field release in Argentina, the Pampas region was surveyed to confirm the establishment of R. conicus, covering the original release sites and most of the overall area of distribution of its host thistles, Carduus species. Sites (n=121) were systematically selected and natural populations of thistles were examined to confirm the presence of the weevil. Twenty four sites with R. conicus were selected to record the weevil’s prevalence on Carduus thoermeri Weinman and Carduus acanthoides L. Additional opportunistic surveys were conducted in other regions of Argentina and Uruguay, more distant from the original release sites. Rhinocyllus conicus was found at 81% of the original release sites and at 69% of the total sites surveyed, an area of approximately 370.000km2. On average, 92% of the examined heads had damage in areas where the weevil was present, showing its high prevalence. A pilot study showed that the oviposition period of the weevils lasted 119days and seed production of C. acanthoides was reduced by 15.5%. These results encourage the implementation of an integrated management of thistles in Argentina, and maybe in other parts of South America.

The Large Decapitating FlyPseudacteon litoralis(Diptera: Phoridae): Successfully Established on Fire Ant Populations in Alabama

ABSTRACT The large fire ant decapitating fly, Pseudacteon litoralis Borgmeier, from northeastern Argentina was successfully released as a self-sustaining biocontrol agent of imported fire ants in south central Alabama in 2005. Five years later, this fly is firmly established at the original release site and has expanded outward at least 18 km. Nevertheless, populations remain very low considering P. litoralis is one of the most abundant fire ant decapitating flies in large areas of its range in South America. The reasons for low densities and why we were only able to establish this fly at 1 of 9 release sites in 4 states (2003–2006) are unknown, but problems with host-matching, release procedures, weather conditions, and competition with previously released decapitating flies are discussed as possible factors.

A Review of Recent Efforts at Biological Control ofCaesalpinia decapetala(Roth) Alston (Fabaceae) in South Africa

A seed-feeding beetle, Sulcobruchus subsuturalis (Pic) (Coleoptera: Chrysomelidae: Bruchinae), was released in South Africa in 1999 as a biological control agent against the invasive, leguminous, scrambling shrub Caesalpinia decapetala (Roth) Alston (Fabaceae). Despite being easy to rear in the laboratory and having been released in large numbers (>350 000) and widely distributed at many field sites, the beetle remains scarce where present and has failed to persist at many of the original release sites. Although eggs are oviposited readily on loose seeds in dishes, the few eggs that were found at release sites in the field were always on seeds still attached to pods hanging on plants. High levels of predation and parasitism were recorded in the field, which may be hindering population expansion by the beetle. Clarity about the taxonomic status of S. subsuturalis, and uncertainty as to the centre of origin of the weed, have led to suspicions that C. decapetala may exist as several biotypes, and that the local variety may not be a suitable host for the form of S. subsuturalis that has been imported into South Africa. These uncertainties should be addressed, together with additional efforts to determine what is happening to the agent in the field. Other phytophagous species from different feeding-guilds need to be investigated as potential biological control agents.

Expansion of the introduced wild boar (Sus scrofa) in the Andean region, Argentinean Patagonia

Wild boar (Sus scrofa) from Siberia were introduced into Patagonia (Argentina) between 1904 and the 1920s. Wild boar were first observed in the Lanín National Park in the 1980s. Their invasion pattern follows rivers and lakes, moving vertically from the original release site in the eastern steppes to the western hillsides. During the last 20 years, the area occupied by wild boar has increased throughout the park from 10% in 1985 to nearly 30% two decades later, mainly in Araucaria-Nothofagus forests and scrubland. These landscapes hold 83% of the current wild boar distribution, with a statistically significant three-fold increase (Sr = 0.891, p<0.01). Pine plantations, grassland–steppe and bare ground are less favoured by the species, with only a two-fold increase or less during the last two decades. Its distribution range has increased to over 70000 ha during the last 20 years, with an average increase of about 3500 ha/y. At this rate, the species would need 50-60 years to cover the entire Lanín National Park, but cold winters, years with poor Araucaria-Nothofagus seed production, increasing predation by puma (Puma concolor), and the possible appearance of new parasites and diseases as the population increases could limit wild boar dispersal to a lower rate.

Status ofCoccobiusnr.Fulvus(Hymenoptera: Aphelinidae), a Parasitoid of Euonymus Scale (Hemiptera: Diaspididae), 12–16 Years After Its Release in Massachusetts

From 1990 to 1995, a classical biocontrol pro gram was conducted in New England against an Asian scale, Unaspis euonymi (Comstock) (Hemi ptera: Diaspididae), which attacks landscape Eu onymus plants. Many Euonymus species are of Asian origin (Flint 1983) and widely planted as ornamentals (Gill et al. 1982). Collection of eu onymus scale natural enemies for release in the USA began in Korea (Drea & Hendrickson 1988; Hendrickson et al. 1991), but from 1990-1995 our laboratory collected additional species near Beijing, China (Van Driesche et al. 1998a), includ ing 2 predators (Chilocorus kuwanae Silvestri and Cybocephalus nr. nipponicus Endrody Younga) and 3 parasitoids (Coccobius nr. fulvus (Compere et Annecke), Encarsia nr. diaspidicola (Silvestri) and Aphytis sp.). Impacts of the 2 pred ators have been documented (Van Driesche et al. 1998b; Van Driesche & Nunn 2003). In 1991-1994, 3,862 adult C. nr. fulvus were re leased at 11 sites; 12,966 adults, nr. diaspidicola at 27 sites; and 801 adult Aphytis sp. at 5 sites in New England (mostly Massachusetts) (Van Drie sche et al. 1998a). By 1994, apparent establish ment (recovery in 1 subsequent year following re lease) had occurred for C. nr. fulvus and E. nr. di aspidicola. No next-year recoveries were made for Aphytis sp., the species released last and in small est numbers. No evidence of spread of any parasi toid was observed. In addition, a pre-existing cos mopolitan polyphagous aphelinid, Encarsia cit rina (Crawford), was observed in samples from Massachusetts. In 1991, it was detected at 44% of 79 sites in southern New England. In 1994, para sitism of dissected adult female euonymus scales by E. citrina, pooled by generation across 18 loca tions in Massachusetts, averaged 13.4% (n 2,174 scales) for the overwintered spring adults, 33.6% (n = 1,271 scales) for the summer generation, and 31.2% (n = 933 scales) for the fall generation. Our objectives here were (1) to sample for ex otic parasitoids of euonymus scale in western Massachusetts in 2006 and 2007 at their original release sites, (2) to sample non-release locations to detect parasitoid spread, and (3) to assess ef fects of exotic parasitoids on the pre-existing par asitoid E. citrina.