Morphological and ecological traits promoting aphid colonization of the Hawaiian Islands

Abstract

Species introductions into novel habitats, especially island ecosystems, can have devastating effects on ecosystem function and stability. Though none are native, at least 96 aphid species can now be found on one or more of the Hawaiian Islands. As aphids cause direct feeding damage and transmit plant viruses, it is important to identify the traits that have enabled these particular species to successfully colonize the archipelago. To address this question, nine morphological and ecological traits that may contribute to successful colonization were assessed for aphids present in Hawaii. As a comparative null model, we assessed the same traits for heterospecific congeners which are not present in the archipelago, but are present elsewhere in the world. Here we report that traits with higher frequencies among colonizing aphid species are: small apterae size, broad host range, anholocycly (i.e., permanent parthenogenesis), and presence in continental USA. Small aphids arriving from the mainland US and capable of feeding on numerous plant species may be intercepted less often by plant protection agents. It is also likely that asexually reproducing species are well suited to the Hawaiian subtropical climate, thereby eliminating the need for sexual phases and egg-laying for overwintering. By understanding the traits that enable aphids to successfully colonize remote islands, it is our hope that plant protection efforts may be enhanced, thereby reducing damage to native ecosystems.

Taxonomy, time and geographic patterns. Chapter 2

“…More synthetic studies have been carried out at guild level (e.g., bark beetles; Brockerhoff et al 2005) or at ecosystem level, especially for forest insects (Liebhold et al 1995, Mattson et al 1996, Niemelä and Mattson 1996, Langor et al 2009). However, continental inventories of alien arthropod species, or even of alien insects, are still lacking in most regions, although such studies are needed to assess which taxonomic or bio-ecological groups of alien species are better invaders or more harmful to the economy or environment, and which ecosystems or habitats are at greater risk (Mondor et al, 2007).…”

Characteristics of exotic ants in North America

“…We can, however, speculate to which extend observed differences between ex- otic and native ant species are influenced by an introduction bias (Blackburn and Duncan 2001;Cassey et al 2004;Jeschke and Strayer 2006;Blackburn and Jeschke 2009;van Kleunen et al 2010). An introduction bias with respect to body size seems likely: Introductions of ants and other invertebrates are typically unintentional (Hulme et al 2008), and since it is easier for small organisms than for large ones to remain undetected by the human eye, small ant species are probably more frequently introduced to North America than large species (see Mondor et al (2007) and Šefrová and Laštůvka (2009) for similar arguments on aphids and lepidopterans, respectively). It is thus possible that observed differences between exotic and native ant species in body size are at least partly attributable to an introduction bias.…”

“…What separates such species from those that have not established populations in exotic ranges? Most studies focusing on this question investigated plants and vertebrates (reviewed in Kolar and Lodge 2001;Jeschke and Strayer 2006;Richardson and Pyšek 2006), whereas only a few studies have looked at invertebrates (Mondor et al 2007;Statzner et al 2008;Šefrová and Laštůvka 2009). Here, we investigate this question for ants (Hymenoptera: Formicidae).…”

Traits related to biological invasion: A note on the applicability of risk assessment tools across taxa

“…Life history and environmental traits related to invasion, highlighting the suggested differences between invasive and native insects that were found through an extensive literature review. Parasitoids more likely to establish than predators (Kimberling 2004) A, C Taxon Diptera and Lepidoptera fastest to disperse, Coleoptera slowest (Paynter and Bellgard 2011) Invasive species predominantly Hemiptera (56.4 %), Lepidoptera (14.9 %), and Hymenoptera (12.9 %) (Matosevic and Zivkovic 2013); Invasive species predominantly Homoptera (39 %), Coleoptera (19 %), Lepidoptera (13 %), and Hymentoptera (13 %) (Mattson et al 2007); Invasive species predominantly Coleoptera, Sternorrhyncha, and Psocoptera (Kenis et al 2007); Homoptera and Lepidoptera most likely to establish (Peacock and Worner 2008) C Feeding method Miners, borers, and leaf-rollers disperse faster than external feeders, and root-, rosette-, and seed-feeders (Paynter and Bellgard 2011) Internal feeders more likely to establish than external feeders (Kimberling 2004) Insects that use single host species are more likely to establish than those that use multiple hosts (Mondor et al 2007) C Diet breadth Diet breadth or Host specificity Invasive insects have a wide diet breadth (generalist) compared to natives (Moller 1996, Cervo et al 2000, Kasper et al 2004, Kimberling 2004, Moeser and Vidal 2005, Snyder and Evans 2006, Mondor et al 2006, Ward and Masters 2007…”