16 research outputs found

    The Tortricidae (Lepidoptera) of the Galapagos Islands, Ecuador

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    Volume: 115Start Page: 185End Page: 22

    Alien insects: Threats and implications for conservation of Galápagos Islands

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    Alien species are the principal threat to the conservation of the Galápagos Islands, but little is known about the status of nonindigenous Galápagos insects and their effects on the biota. Currently, 463 alien insect species have probably been introduced to the Galápagos, an increase of 186 unintentional species introductions since an inventory in 1998. Alien insects now constitute 23% of the total insect fauna. Six species are known to be invasive and a threat to the biota: two species of fire ant and two wasps, a scale insect, and an ectoparasitic dipteran. The ecological impacts of the remaining species are unknown, making the prioritization of action for conservation management difficult. Thus, a newly developed and simple scoring system is presented to predict their potential invasiveness based on trophic functional role, distribution in Galápagos, and history of invasiveness elsewhere. An additional 52 species are predicted to be highly invasive. The endemic flora is most at risk because the largest proportion (42%) of the introduced species is herbivores. Plant populations are threatened principally by vectors of plant disease and by phloem and leaf feeders. Introduced preda

    Polistes versicolor (Hymenoptera: Vespidae), an Introduced Wasp in the Galapagos Islands: Its Life Cycle and Ecological Impact

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    The yellow paper wasp, Polistes versicolor (Olivier) was first recorded in the Galapagos archipelago in 1988. Its life cycle and ecological impacts were studied on two islands 11 yr after it was first discovered. This invasive wasp adapted quickly and was found in most environments. Colony counts and adult wasp monitoring showed a strong preference for drier habitats. Nest activities were seasonally synchronized, nest building followed the rains in the hot season (typically January-May), when insect prey increases, and peaked as temperature and rains started to decline. Next, the number of adult wasps peaked during the cool season when there is barely any rain in the drier zones. In Galapagos, almost half of the prey loads of P. versicolor were lepidopteran larvae, but wasps also carried spiders, beetles, and flies back to the colonies. An estimated average of 329 mg of fresh insect prey was consumed per day for an average colony of 120-150 wasp larvae. The wasps preyed upon native and introduced insects, but likely also affect insectivorous vertebrates as competitors for food. Wasps may also compete with native pollinators as they regularly visited flowers to collect nectar, and have been recorded visiting at least 93 plant species in Galapagos, including 66 endemic and native plants. Colonies were attacked by a predatory moth, Taygete sphecophila (Meyrick) (Lepidoptera: Autostichidae), but colony development was not arrested. High wasp numbers also affect the activities of residents and tourists. A management program for this invasive species in the archipelago is essential
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