Little is known regarding pollination webs involving island coastal plants and pollinators, and roles that nonnative flower visitors may play in these interaction networks. Plant-pollinator observations made in March 2008 and 2009 were used to describe the pollination network for Ka'ena Point, one of Hawai'i's best-conserved coastal communities. The network includes 15 native plant species, two native bee species, and 26 nonnative insect taxa, forming 119 interactions. Network connectance is 29.4% and weighted nestedness is 17.9, which are similar to values of other dry-habitat, island networks. The network's structure has a core of generalized pollinators plus several more-specialized pollinators. Nearly all plant species interact with two or more generalist pollinators and a variable number of specialists. Small, nonnative bees (Lasioglossum, Ceratina), wasps (Proconura), and flies (mostly Tachinidae) were responsible for 72.7% of flower visits, and they visit five plant species not visited by native bees. The two native visitors were the bees Hylaeus anthracinus and H. longiceps (both proposed as endangered). Hylaeus spp. (especially females) provided 19.8% of flower visits, foraging at high visitation rates and on many species, including the endangered Scaevola coriacea and Sesbania tomentosa. In Hawai'i's coastal habitat, nonnative insects form novel interactions with native species and may maintain an ecosystem's function following loss of most of the original native pollinators. However, their high visitation rates suggest that the two remaining native Hylaeus species are potentially important pollinators for many of the native plants on which they rely for nectar and pollen resources.

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The parasitoid wasp Woldstedtius flavolineatus (Gravenhorst) (Ichneumoni- dae) attacks the larvae of syrphid flies (Syrphidae). Woldstedtius flavolineatus was collected in Hawaii for the first time during an extensive malaise trap-based survey of parasitoids in Hawaiian forests. Since its initial collection on Hawaii Island in January 2006, it has been collected at five additional sites on Hawaii Island and at one site each on Maui and Oahu. Malaise trap results from Hakalau Forest National Wildlife Refuge showed a strong seasonal pattern of abundance, with peak population levels reached during July-September. Rearing of its host, Allograpta obliqua (Say), collected from koa (Acacia koa Gray) at Hakalau over two days, revealed a parasitism rate of ap- proximately 95%. Broader impacts of this alien wasp are unknown, but a reduction in host syrphid abundance could result in an increase in numbers of psyllids and aphids (Homoptera) that are preyed upon by syrphid larvae. Furthermore, a reduction in adult syrphids could impact the reproductive success of some of the plants they pollinate.

Two hypothesized benefits of delayed dispersal are access to resources and prolonged brood care (or parental nepotism). Resource abundance (mistletoe wealth) is a key factor influencing whether sons stay home in western bluebirds, Sialia mexicana, but nepotism is also observed. Western bluebird sons commonly remain in their family groups throughout the winter, whereas daughters usually disperse before winter. Because pairing often takes place in winter groups, with newly formed pairs settling on exclusive all-purpose territories in spring, selection for sexual competition and nepotism co-occur and may simultaneously influence patterns of aggression within groups. We measured aggression at mealworm feeder stations, finding evidence of (1) intrasexual aggression against unrelated group members by experienced breeders of both sexes and (2) nepotism towards sons and daughters by experienced breeder females but not by experienced breeder males. Females showed much higher levels of aggression towards same-sex immigrants than males did. Experienced breeder males did not evict their sons from the natal territory, but they were 12 times more aggressive towards sons than breeder females were towards daughters. They were also equally aggressive towards sons and immigrant males, suggesting that local breeding competition and the benefits of intrasexual dominance counter the benefits of paternal nepotism towards sons. (C) 2009 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Through intentional and accidental introduction, more than 100 species of alien Ichneumonidae and Braconidae (Hymenoptera) have become established in the Hawaiian Islands. The extent to which these parasitoid wasps have penetrated native wet forests was investigated over a 1,765 m elevation gradient on windward Hawai'i Island. For > 1 year, malaise traps were used to continuously monitor parasitoid abundance and species richness in nine sites over three elevations. A total of 18,996 individuals from 16 subfamilies were collected. Overall, the fauna was dominated by aliens, with 44 of 58 species foreign to the Hawaiian Islands. Ichneumonidae was dominant over Braconidae in terms of both diversity and abundance, comprising 67.5% of individuals and 69.0% of species collected. Parasitoid abundance and species richness varied significantly with elevation: abundance was greater at mid and high elevations compared to low elevation while species richness increased with increasing elevation, with all three elevations differing significantly from each other. Nine species purposely introduced to control pest insects were found, but one braconid, Meteorus laphygmae, comprised 98.0% of this assemblage, or 28.3% of the entire fauna. Endemic species, primarily within the genera Spolas and Enicospilus, were collected almost exclusively at mid- and high-elevation sites, where they made up 22.1% and 36.0% of the total catch, respectively. Overall, 75.9% of species and 96.0% of individuals are inferred to parasitize Lepidoptera larvae and pupae. Our results support previous data indicating that alien parasitoids have deeply penetrated native forest habitats and may have substantial impacts on Hawaiian ecosystems.